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1.1 root 1: /* Expands front end tree to back end RTL for GNU C-Compiler
2: Copyright (C) 1987, 1988, 1989, 1992, 1993 Free Software Foundation, Inc.
3:
4: This file is part of GNU CC.
5:
6: GNU CC is free software; you can redistribute it and/or modify
7: it under the terms of the GNU General Public License as published by
8: the Free Software Foundation; either version 2, or (at your option)
9: any later version.
10:
11: GNU CC is distributed in the hope that it will be useful,
12: but WITHOUT ANY WARRANTY; without even the implied warranty of
13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14: GNU General Public License for more details.
15:
16: You should have received a copy of the GNU General Public License
17: along with GNU CC; see the file COPYING. If not, write to
18: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
19:
20:
21: /* This file handles the generation of rtl code from tree structure
22: above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
23: It also creates the rtl expressions for parameters and auto variables
24: and has full responsibility for allocating stack slots.
25:
26: The functions whose names start with `expand_' are called by the
27: parser to generate RTL instructions for various kinds of constructs.
28:
29: Some control and binding constructs require calling several such
30: functions at different times. For example, a simple if-then
31: is expanded by calling `expand_start_cond' (with the condition-expression
32: as argument) before parsing the then-clause and calling `expand_end_cond'
33: after parsing the then-clause. */
34:
35: #include "config.h"
36:
37: #include <stdio.h>
38: #include <ctype.h>
39:
40: #include "rtl.h"
41: #include "tree.h"
42: #include "flags.h"
43: #include "function.h"
44: #include "insn-flags.h"
45: #include "insn-config.h"
46: #include "insn-codes.h"
47: #include "expr.h"
48: #include "hard-reg-set.h"
49: #include "obstack.h"
50: #include "loop.h"
51: #include "recog.h"
52: #include "machmode.h"
53:
54: #include "bytecode.h"
55: #include "bc-typecd.h"
56: #include "bc-opcode.h"
57: #include "bc-optab.h"
58: #include "bc-emit.h"
59:
60: #define obstack_chunk_alloc xmalloc
61: #define obstack_chunk_free free
62: struct obstack stmt_obstack;
63:
64: /* Filename and line number of last line-number note,
65: whether we actually emitted it or not. */
66: char *emit_filename;
67: int emit_lineno;
68:
69: /* Nonzero if within a ({...}) grouping, in which case we must
70: always compute a value for each expr-stmt in case it is the last one. */
71:
72: int expr_stmts_for_value;
73:
74: /* Each time we expand an expression-statement,
75: record the expr's type and its RTL value here. */
76:
77: static tree last_expr_type;
78: static rtx last_expr_value;
79:
80: /* Each time we expand the end of a binding contour (in `expand_end_bindings')
81: and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
82: This is used by the `remember_end_note' function to record the endpoint
83: of each generated block in its associated BLOCK node. */
84:
85: static rtx last_block_end_note;
86:
87: /* Number of binding contours started so far in this function. */
88:
89: int block_start_count;
90:
91: /* Nonzero if function being compiled needs to
92: return the address of where it has put a structure value. */
93:
94: extern int current_function_returns_pcc_struct;
95:
96: /* Label that will go on parm cleanup code, if any.
97: Jumping to this label runs cleanup code for parameters, if
98: such code must be run. Following this code is the logical return label. */
99:
100: extern rtx cleanup_label;
101:
102: /* Label that will go on function epilogue.
103: Jumping to this label serves as a "return" instruction
104: on machines which require execution of the epilogue on all returns. */
105:
106: extern rtx return_label;
107:
108: /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
109: So we can mark them all live at the end of the function, if nonopt. */
110: extern rtx save_expr_regs;
111:
112: /* Offset to end of allocated area of stack frame.
113: If stack grows down, this is the address of the last stack slot allocated.
114: If stack grows up, this is the address for the next slot. */
115: extern int frame_offset;
116:
117: /* Label to jump back to for tail recursion, or 0 if we have
118: not yet needed one for this function. */
119: extern rtx tail_recursion_label;
120:
121: /* Place after which to insert the tail_recursion_label if we need one. */
122: extern rtx tail_recursion_reentry;
123:
124: /* Location at which to save the argument pointer if it will need to be
125: referenced. There are two cases where this is done: if nonlocal gotos
126: exist, or if vars whose is an offset from the argument pointer will be
127: needed by inner routines. */
128:
129: extern rtx arg_pointer_save_area;
130:
131: /* Chain of all RTL_EXPRs that have insns in them. */
132: extern tree rtl_expr_chain;
133:
134: #if 0 /* Turned off because 0 seems to work just as well. */
135: /* Cleanup lists are required for binding levels regardless of whether
136: that binding level has cleanups or not. This node serves as the
137: cleanup list whenever an empty list is required. */
138: static tree empty_cleanup_list;
139: #endif
140:
141: /* Functions and data structures for expanding case statements. */
142:
143: /* Case label structure, used to hold info on labels within case
144: statements. We handle "range" labels; for a single-value label
145: as in C, the high and low limits are the same.
146:
147: A chain of case nodes is initially maintained via the RIGHT fields
148: in the nodes. Nodes with higher case values are later in the list.
149:
150: Switch statements can be output in one of two forms. A branch table
151: is used if there are more than a few labels and the labels are dense
152: within the range between the smallest and largest case value. If a
153: branch table is used, no further manipulations are done with the case
154: node chain.
155:
156: The alternative to the use of a branch table is to generate a series
157: of compare and jump insns. When that is done, we use the LEFT, RIGHT,
158: and PARENT fields to hold a binary tree. Initially the tree is
159: totally unbalanced, with everything on the right. We balance the tree
160: with nodes on the left having lower case values than the parent
161: and nodes on the right having higher values. We then output the tree
162: in order. */
163:
164: struct case_node
165: {
166: struct case_node *left; /* Left son in binary tree */
167: struct case_node *right; /* Right son in binary tree; also node chain */
168: struct case_node *parent; /* Parent of node in binary tree */
169: tree low; /* Lowest index value for this label */
170: tree high; /* Highest index value for this label */
171: tree code_label; /* Label to jump to when node matches */
172: };
173:
174: typedef struct case_node case_node;
175: typedef struct case_node *case_node_ptr;
176:
177: /* These are used by estimate_case_costs and balance_case_nodes. */
178:
179: /* This must be a signed type, and non-ANSI compilers lack signed char. */
180: static short *cost_table;
181: static int use_cost_table;
182:
183: static int estimate_case_costs ();
184: static void balance_case_nodes ();
185: static void emit_case_nodes ();
186: static void group_case_nodes ();
187: static void emit_jump_if_reachable ();
188:
189: static int warn_if_unused_value ();
190: static void expand_goto_internal ();
191: static void bc_expand_goto_internal ();
192: static int expand_fixup ();
193: static void bc_expand_fixup ();
194: void fixup_gotos ();
195: static void bc_fixup_gotos ();
196: void free_temp_slots ();
197: static void expand_cleanups ();
198: static void expand_null_return_1 ();
199: static int tail_recursion_args ();
200: static void do_jump_if_equal ();
201: int bc_expand_exit_loop_if_false ();
202: void bc_expand_start_cond ();
203: void bc_expand_end_cond ();
204: void bc_expand_start_else ();
205: void bc_expand_end_bindings ();
206: void bc_expand_start_case ();
207: void bc_check_for_full_enumeration_handling ();
208: void bc_expand_end_case ();
209: void bc_expand_decl ();
210:
211: extern rtx bc_allocate_local ();
212: extern rtx bc_allocate_variable_array ();
213:
214: /* Stack of control and binding constructs we are currently inside.
215:
216: These constructs begin when you call `expand_start_WHATEVER'
217: and end when you call `expand_end_WHATEVER'. This stack records
218: info about how the construct began that tells the end-function
219: what to do. It also may provide information about the construct
220: to alter the behavior of other constructs within the body.
221: For example, they may affect the behavior of C `break' and `continue'.
222:
223: Each construct gets one `struct nesting' object.
224: All of these objects are chained through the `all' field.
225: `nesting_stack' points to the first object (innermost construct).
226: The position of an entry on `nesting_stack' is in its `depth' field.
227:
228: Each type of construct has its own individual stack.
229: For example, loops have `loop_stack'. Each object points to the
230: next object of the same type through the `next' field.
231:
232: Some constructs are visible to `break' exit-statements and others
233: are not. Which constructs are visible depends on the language.
234: Therefore, the data structure allows each construct to be visible
235: or not, according to the args given when the construct is started.
236: The construct is visible if the `exit_label' field is non-null.
237: In that case, the value should be a CODE_LABEL rtx. */
238:
239: struct nesting
240: {
241: struct nesting *all;
242: struct nesting *next;
243: int depth;
244: rtx exit_label;
245: union
246: {
247: /* For conds (if-then and if-then-else statements). */
248: struct
249: {
250: /* Label for the end of the if construct.
251: There is none if EXITFLAG was not set
252: and no `else' has been seen yet. */
253: rtx endif_label;
254: /* Label for the end of this alternative.
255: This may be the end of the if or the next else/elseif. */
256: rtx next_label;
257: } cond;
258: /* For loops. */
259: struct
260: {
261: /* Label at the top of the loop; place to loop back to. */
262: rtx start_label;
263: /* Label at the end of the whole construct. */
264: rtx end_label;
265: /* Label for `continue' statement to jump to;
266: this is in front of the stepper of the loop. */
267: rtx continue_label;
268: } loop;
269: /* For variable binding contours. */
270: struct
271: {
272: /* Sequence number of this binding contour within the function,
273: in order of entry. */
274: int block_start_count;
275: /* Nonzero => value to restore stack to on exit. Complemented by
276: bc_stack_level (see below) when generating bytecodes. */
277: rtx stack_level;
278: /* The NOTE that starts this contour.
279: Used by expand_goto to check whether the destination
280: is within each contour or not. */
281: rtx first_insn;
282: /* Innermost containing binding contour that has a stack level. */
283: struct nesting *innermost_stack_block;
284: /* List of cleanups to be run on exit from this contour.
285: This is a list of expressions to be evaluated.
286: The TREE_PURPOSE of each link is the ..._DECL node
287: which the cleanup pertains to. */
288: tree cleanups;
289: /* List of cleanup-lists of blocks containing this block,
290: as they were at the locus where this block appears.
291: There is an element for each containing block,
292: ordered innermost containing block first.
293: The tail of this list can be 0 (was empty_cleanup_list),
294: if all remaining elements would be empty lists.
295: The element's TREE_VALUE is the cleanup-list of that block,
296: which may be null. */
297: tree outer_cleanups;
298: /* Chain of labels defined inside this binding contour.
299: For contours that have stack levels or cleanups. */
300: struct label_chain *label_chain;
301: /* Number of function calls seen, as of start of this block. */
302: int function_call_count;
303: /* Bytecode specific: stack level to restore stack to on exit. */
304: int bc_stack_level;
305: } block;
306: /* For switch (C) or case (Pascal) statements,
307: and also for dummies (see `expand_start_case_dummy'). */
308: struct
309: {
310: /* The insn after which the case dispatch should finally
311: be emitted. Zero for a dummy. */
312: rtx start;
313: /* For bytecodes, the case table is in-lined right in the code.
314: A label is needed for skipping over this block. It is only
315: used when generating bytecodes. */
316: rtx skip_label;
317: /* A list of case labels, kept in ascending order by value
318: as the list is built.
319: During expand_end_case, this list may be rearranged into a
320: nearly balanced binary tree. */
321: struct case_node *case_list;
322: /* Label to jump to if no case matches. */
323: tree default_label;
324: /* The expression to be dispatched on. */
325: tree index_expr;
326: /* Type that INDEX_EXPR should be converted to. */
327: tree nominal_type;
328: /* Number of range exprs in case statement. */
329: int num_ranges;
330: /* Name of this kind of statement, for warnings. */
331: char *printname;
332: /* Nonzero if a case label has been seen in this case stmt. */
333: char seenlabel;
334: } case_stmt;
335: /* For exception contours. */
336: struct
337: {
338: /* List of exceptions raised. This is a TREE_LIST
339: of whatever you want. */
340: tree raised;
341: /* List of exceptions caught. This is also a TREE_LIST
342: of whatever you want. As a special case, it has the
343: value `void_type_node' if it handles default exceptions. */
344: tree handled;
345:
346: /* First insn of TRY block, in case resumptive model is needed. */
347: rtx first_insn;
348: /* Label for the catch clauses. */
349: rtx except_label;
350: /* Label for unhandled exceptions. */
351: rtx unhandled_label;
352: /* Label at the end of whole construct. */
353: rtx after_label;
354: /* Label which "escapes" the exception construct.
355: Like EXIT_LABEL for BREAK construct, but for exceptions. */
356: rtx escape_label;
357: } except_stmt;
358: } data;
359: };
360:
361: /* Chain of all pending binding contours. */
362: struct nesting *block_stack;
363:
364: /* If any new stacks are added here, add them to POPSTACKS too. */
365:
366: /* Chain of all pending binding contours that restore stack levels
367: or have cleanups. */
368: struct nesting *stack_block_stack;
369:
370: /* Chain of all pending conditional statements. */
371: struct nesting *cond_stack;
372:
373: /* Chain of all pending loops. */
374: struct nesting *loop_stack;
375:
376: /* Chain of all pending case or switch statements. */
377: struct nesting *case_stack;
378:
379: /* Chain of all pending exception contours. */
380: struct nesting *except_stack;
381:
382: /* Separate chain including all of the above,
383: chained through the `all' field. */
384: struct nesting *nesting_stack;
385:
386: /* Number of entries on nesting_stack now. */
387: int nesting_depth;
388:
389: /* Allocate and return a new `struct nesting'. */
390:
391: #define ALLOC_NESTING() \
392: (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
393:
394: /* Pop the nesting stack element by element until we pop off
395: the element which is at the top of STACK.
396: Update all the other stacks, popping off elements from them
397: as we pop them from nesting_stack. */
398:
399: #define POPSTACK(STACK) \
400: do { struct nesting *target = STACK; \
401: struct nesting *this; \
402: do { this = nesting_stack; \
403: if (loop_stack == this) \
404: loop_stack = loop_stack->next; \
405: if (cond_stack == this) \
406: cond_stack = cond_stack->next; \
407: if (block_stack == this) \
408: block_stack = block_stack->next; \
409: if (stack_block_stack == this) \
410: stack_block_stack = stack_block_stack->next; \
411: if (case_stack == this) \
412: case_stack = case_stack->next; \
413: if (except_stack == this) \
414: except_stack = except_stack->next; \
415: nesting_depth = nesting_stack->depth - 1; \
416: nesting_stack = this->all; \
417: obstack_free (&stmt_obstack, this); } \
418: while (this != target); } while (0)
419:
420: /* In some cases it is impossible to generate code for a forward goto
421: until the label definition is seen. This happens when it may be necessary
422: for the goto to reset the stack pointer: we don't yet know how to do that.
423: So expand_goto puts an entry on this fixup list.
424: Each time a binding contour that resets the stack is exited,
425: we check each fixup.
426: If the target label has now been defined, we can insert the proper code. */
427:
428: struct goto_fixup
429: {
430: /* Points to following fixup. */
431: struct goto_fixup *next;
432: /* Points to the insn before the jump insn.
433: If more code must be inserted, it goes after this insn. */
434: rtx before_jump;
435: /* The LABEL_DECL that this jump is jumping to, or 0
436: for break, continue or return. */
437: tree target;
438: /* The BLOCK for the place where this goto was found. */
439: tree context;
440: /* The CODE_LABEL rtx that this is jumping to. */
441: rtx target_rtl;
442: /* Number of binding contours started in current function
443: before the label reference. */
444: int block_start_count;
445: /* The outermost stack level that should be restored for this jump.
446: Each time a binding contour that resets the stack is exited,
447: if the target label is *not* yet defined, this slot is updated. */
448: rtx stack_level;
449: /* List of lists of cleanup expressions to be run by this goto.
450: There is one element for each block that this goto is within.
451: The tail of this list can be 0 (was empty_cleanup_list),
452: if all remaining elements would be empty.
453: The TREE_VALUE contains the cleanup list of that block as of the
454: time this goto was seen.
455: The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
456: tree cleanup_list_list;
457:
458: /* Bytecode specific members follow */
459:
460: /* The label that this jump is jumping to, or 0 for break, continue
461: or return. */
462: struct bc_label *bc_target;
463:
464: /* The label we use for the fixup patch */
465: struct bc_label *label;
466:
467: /* True (non-0) if fixup has been handled */
468: int bc_handled:1;
469:
470: /* Like stack_level above, except refers to the interpreter stack */
471: int bc_stack_level;
472: };
473:
474: static struct goto_fixup *goto_fixup_chain;
475:
476: /* Within any binding contour that must restore a stack level,
477: all labels are recorded with a chain of these structures. */
478:
479: struct label_chain
480: {
481: /* Points to following fixup. */
482: struct label_chain *next;
483: tree label;
484: };
485:
486: void
487: init_stmt ()
488: {
489: gcc_obstack_init (&stmt_obstack);
490: #if 0
491: empty_cleanup_list = build_tree_list (NULL_TREE, NULL_TREE);
492: #endif
493: }
494:
495: void
496: init_stmt_for_function ()
497: {
498: /* We are not currently within any block, conditional, loop or case. */
499: block_stack = 0;
500: loop_stack = 0;
501: case_stack = 0;
502: cond_stack = 0;
503: nesting_stack = 0;
504: nesting_depth = 0;
505:
506: block_start_count = 0;
507:
508: /* No gotos have been expanded yet. */
509: goto_fixup_chain = 0;
510:
511: /* We are not processing a ({...}) grouping. */
512: expr_stmts_for_value = 0;
513: last_expr_type = 0;
514: }
515:
516: void
517: save_stmt_status (p)
518: struct function *p;
519: {
520: p->block_stack = block_stack;
521: p->stack_block_stack = stack_block_stack;
522: p->cond_stack = cond_stack;
523: p->loop_stack = loop_stack;
524: p->case_stack = case_stack;
525: p->nesting_stack = nesting_stack;
526: p->nesting_depth = nesting_depth;
527: p->block_start_count = block_start_count;
528: p->last_expr_type = last_expr_type;
529: p->last_expr_value = last_expr_value;
530: p->expr_stmts_for_value = expr_stmts_for_value;
531: p->emit_filename = emit_filename;
532: p->emit_lineno = emit_lineno;
533: p->goto_fixup_chain = goto_fixup_chain;
534: }
535:
536: void
537: restore_stmt_status (p)
538: struct function *p;
539: {
540: block_stack = p->block_stack;
541: stack_block_stack = p->stack_block_stack;
542: cond_stack = p->cond_stack;
543: loop_stack = p->loop_stack;
544: case_stack = p->case_stack;
545: nesting_stack = p->nesting_stack;
546: nesting_depth = p->nesting_depth;
547: block_start_count = p->block_start_count;
548: last_expr_type = p->last_expr_type;
549: last_expr_value = p->last_expr_value;
550: expr_stmts_for_value = p->expr_stmts_for_value;
551: emit_filename = p->emit_filename;
552: emit_lineno = p->emit_lineno;
553: goto_fixup_chain = p->goto_fixup_chain;
554: }
555:
556: /* Emit a no-op instruction. */
557:
558: void
559: emit_nop ()
560: {
561: rtx last_insn;
562:
563: if (!output_bytecode)
564: {
565: last_insn = get_last_insn ();
566: if (!optimize
567: && (GET_CODE (last_insn) == CODE_LABEL
568: || prev_real_insn (last_insn) == 0))
569: emit_insn (gen_nop ());
570: }
571: }
572:
573: /* Return the rtx-label that corresponds to a LABEL_DECL,
574: creating it if necessary. */
575:
576: rtx
577: label_rtx (label)
578: tree label;
579: {
580: if (TREE_CODE (label) != LABEL_DECL)
581: abort ();
582:
583: if (DECL_RTL (label))
584: return DECL_RTL (label);
585:
586: return DECL_RTL (label) = gen_label_rtx ();
587: }
588:
589: /* Add an unconditional jump to LABEL as the next sequential instruction. */
590:
591: void
592: emit_jump (label)
593: rtx label;
594: {
595: do_pending_stack_adjust ();
596: emit_jump_insn (gen_jump (label));
597: emit_barrier ();
598: }
599:
600: /* Emit code to jump to the address
601: specified by the pointer expression EXP. */
602:
603: void
604: expand_computed_goto (exp)
605: tree exp;
606: {
607: if (output_bytecode)
608: {
609: bc_expand_expr (exp);
610: bc_emit_instruction (jumpP);
611: }
612: else
613: {
614: rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
615: emit_queue ();
616: emit_indirect_jump (x);
617: }
618: }
619:
620: /* Handle goto statements and the labels that they can go to. */
621:
622: /* Specify the location in the RTL code of a label LABEL,
623: which is a LABEL_DECL tree node.
624:
625: This is used for the kind of label that the user can jump to with a
626: goto statement, and for alternatives of a switch or case statement.
627: RTL labels generated for loops and conditionals don't go through here;
628: they are generated directly at the RTL level, by other functions below.
629:
630: Note that this has nothing to do with defining label *names*.
631: Languages vary in how they do that and what that even means. */
632:
633: void
634: expand_label (label)
635: tree label;
636: {
637: struct label_chain *p;
638:
639: if (output_bytecode)
640: {
641: if (! DECL_RTL (label))
642: DECL_RTL (label) = bc_gen_rtx ((char *) 0, 0, bc_get_bytecode_label ());
643: if (! bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (DECL_RTL (label))))
644: error ("multiply defined label");
645: return;
646: }
647:
648: do_pending_stack_adjust ();
649: emit_label (label_rtx (label));
650: if (DECL_NAME (label))
651: LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
652:
653: if (stack_block_stack != 0)
654: {
655: p = (struct label_chain *) oballoc (sizeof (struct label_chain));
656: p->next = stack_block_stack->data.block.label_chain;
657: stack_block_stack->data.block.label_chain = p;
658: p->label = label;
659: }
660: }
661:
662: /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
663: from nested functions. */
664:
665: void
666: declare_nonlocal_label (label)
667: tree label;
668: {
669: nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
670: LABEL_PRESERVE_P (label_rtx (label)) = 1;
671: if (nonlocal_goto_handler_slot == 0)
672: {
673: nonlocal_goto_handler_slot
674: = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
675: emit_stack_save (SAVE_NONLOCAL,
676: &nonlocal_goto_stack_level,
677: PREV_INSN (tail_recursion_reentry));
678: }
679: }
680:
681: /* Generate RTL code for a `goto' statement with target label LABEL.
682: LABEL should be a LABEL_DECL tree node that was or will later be
683: defined with `expand_label'. */
684:
685: void
686: expand_goto (label)
687: tree label;
688: {
689: tree context;
690:
691: if (output_bytecode)
692: {
693: expand_goto_internal (label, label_rtx (label), NULL_RTX);
694: return;
695: }
696:
697: /* Check for a nonlocal goto to a containing function. */
698: context = decl_function_context (label);
699: if (context != 0 && context != current_function_decl)
700: {
701: struct function *p = find_function_data (context);
702: rtx label_ref = gen_rtx (LABEL_REF, Pmode, label_rtx (label));
703: rtx temp;
704:
705: p->has_nonlocal_label = 1;
706: current_function_has_nonlocal_goto = 1;
707: LABEL_REF_NONLOCAL_P (label_ref) = 1;
708:
709: /* Copy the rtl for the slots so that they won't be shared in
710: case the virtual stack vars register gets instantiated differently
711: in the parent than in the child. */
712:
713: #if HAVE_nonlocal_goto
714: if (HAVE_nonlocal_goto)
715: emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
716: copy_rtx (p->nonlocal_goto_handler_slot),
717: copy_rtx (p->nonlocal_goto_stack_level),
718: label_ref));
719: else
720: #endif
721: {
722: rtx addr;
723:
724: /* Restore frame pointer for containing function.
725: This sets the actual hard register used for the frame pointer
726: to the location of the function's incoming static chain info.
727: The non-local goto handler will then adjust it to contain the
728: proper value and reload the argument pointer, if needed. */
729: emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
730:
731: /* We have now loaded the frame pointer hardware register with
732: the address of that corresponds to the start of the virtual
733: stack vars. So replace virtual_stack_vars_rtx in all
734: addresses we use with stack_pointer_rtx. */
735:
736: /* Get addr of containing function's current nonlocal goto handler,
737: which will do any cleanups and then jump to the label. */
738: addr = copy_rtx (p->nonlocal_goto_handler_slot);
739: temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
740: hard_frame_pointer_rtx));
741:
742: /* Restore the stack pointer. Note this uses fp just restored. */
743: addr = p->nonlocal_goto_stack_level;
744: if (addr)
745: addr = replace_rtx (copy_rtx (addr),
746: virtual_stack_vars_rtx,
747: hard_frame_pointer_rtx);
748:
749: emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
750:
751: /* Put in the static chain register the nonlocal label address. */
752: emit_move_insn (static_chain_rtx, label_ref);
753: /* USE of hard_frame_pointer_rtx added for consistency; not clear if
754: really needed. */
755: emit_insn (gen_rtx (USE, VOIDmode, hard_frame_pointer_rtx));
756: emit_insn (gen_rtx (USE, VOIDmode, stack_pointer_rtx));
757: emit_insn (gen_rtx (USE, VOIDmode, static_chain_rtx));
758: emit_indirect_jump (temp);
759: }
760: }
761: else
762: expand_goto_internal (label, label_rtx (label), NULL_RTX);
763: }
764:
765: /* Generate RTL code for a `goto' statement with target label BODY.
766: LABEL should be a LABEL_REF.
767: LAST_INSN, if non-0, is the rtx we should consider as the last
768: insn emitted (for the purposes of cleaning up a return). */
769:
770: static void
771: expand_goto_internal (body, label, last_insn)
772: tree body;
773: rtx label;
774: rtx last_insn;
775: {
776: struct nesting *block;
777: rtx stack_level = 0;
778:
779: /* NOTICE! If a bytecode instruction other than `jump' is needed,
780: then the caller has to call bc_expand_goto_internal()
781: directly. This is rather an exceptional case, and there aren't
782: that many places where this is necessary. */
783: if (output_bytecode)
784: {
785: expand_goto_internal (body, label, last_insn);
786: return;
787: }
788:
789: if (GET_CODE (label) != CODE_LABEL)
790: abort ();
791:
792: /* If label has already been defined, we can tell now
793: whether and how we must alter the stack level. */
794:
795: if (PREV_INSN (label) != 0)
796: {
797: /* Find the innermost pending block that contains the label.
798: (Check containment by comparing insn-uids.)
799: Then restore the outermost stack level within that block,
800: and do cleanups of all blocks contained in it. */
801: for (block = block_stack; block; block = block->next)
802: {
803: if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
804: break;
805: if (block->data.block.stack_level != 0)
806: stack_level = block->data.block.stack_level;
807: /* Execute the cleanups for blocks we are exiting. */
808: if (block->data.block.cleanups != 0)
809: {
810: expand_cleanups (block->data.block.cleanups, NULL_TREE);
811: do_pending_stack_adjust ();
812: }
813: }
814:
815: if (stack_level)
816: {
817: /* Ensure stack adjust isn't done by emit_jump, as this would clobber
818: the stack pointer. This one should be deleted as dead by flow. */
819: clear_pending_stack_adjust ();
820: do_pending_stack_adjust ();
821: emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
822: }
823:
824: if (body != 0 && DECL_TOO_LATE (body))
825: error ("jump to `%s' invalidly jumps into binding contour",
826: IDENTIFIER_POINTER (DECL_NAME (body)));
827: }
828: /* Label not yet defined: may need to put this goto
829: on the fixup list. */
830: else if (! expand_fixup (body, label, last_insn))
831: {
832: /* No fixup needed. Record that the label is the target
833: of at least one goto that has no fixup. */
834: if (body != 0)
835: TREE_ADDRESSABLE (body) = 1;
836: }
837:
838: emit_jump (label);
839: }
840:
841: /* Generate a jump with OPCODE to the given bytecode LABEL which is
842: found within BODY. */
843: static void
844: bc_expand_goto_internal (opcode, label, body)
845: enum bytecode_opcode opcode;
846: struct bc_label *label;
847: tree body;
848: {
849: struct nesting *block;
850: int stack_level = -1;
851:
852: /* If the label is defined, adjust the stack as necessary.
853: If it's not defined, we have to push the reference on the
854: fixup list. */
855:
856: if (label->defined)
857: {
858:
859: /* Find the innermost pending block that contains the label.
860: (Check containment by comparing bytecode uids.) Then restore the
861: outermost stack level within that block. */
862:
863: for (block = block_stack; block; block = block->next)
864: {
865: if (BYTECODE_BC_LABEL (block->data.block.first_insn)->uid < label->uid)
866: break;
867: if (block->data.block.bc_stack_level)
868: stack_level = block->data.block.bc_stack_level;
869:
870: /* Execute the cleanups for blocks we are exiting. */
871: if (block->data.block.cleanups != 0)
872: {
873: expand_cleanups (block->data.block.cleanups, NULL_TREE);
874: do_pending_stack_adjust ();
875: }
876: }
877:
878: /* Restore the stack level. If we need to adjust the stack, we
879: must do so after the jump, since the jump may depend on
880: what's on the stack. Thus, any stack-modifying conditional
881: jumps (these are the only ones that rely on what's on the
882: stack) go into the fixup list. */
883:
884: if (stack_level >= 0
885: && stack_depth != stack_level
886: && opcode != jump)
887:
888: bc_expand_fixup (opcode, label, stack_level);
889: else
890: {
891: if (stack_level >= 0)
892: bc_adjust_stack (stack_depth - stack_level);
893:
894: if (body && DECL_BIT_FIELD (body))
895: error ("jump to `%s' invalidly jumps into binding contour",
896: IDENTIFIER_POINTER (DECL_NAME (body)));
897:
898: /* Emit immediate jump */
899: bc_emit_bytecode (opcode);
900: bc_emit_bytecode_labelref (label);
901:
902: #ifdef DEBUG_PRINT_CODE
903: fputc ('\n', stderr);
904: #endif
905: }
906: }
907: else
908: /* Put goto in the fixup list */
909: bc_expand_fixup (opcode, label, stack_level);
910: }
911:
912: /* Generate if necessary a fixup for a goto
913: whose target label in tree structure (if any) is TREE_LABEL
914: and whose target in rtl is RTL_LABEL.
915:
916: If LAST_INSN is nonzero, we pretend that the jump appears
917: after insn LAST_INSN instead of at the current point in the insn stream.
918:
919: The fixup will be used later to insert insns just before the goto.
920: Those insns will restore the stack level as appropriate for the
921: target label, and will (in the case of C++) also invoke any object
922: destructors which have to be invoked when we exit the scopes which
923: are exited by the goto.
924:
925: Value is nonzero if a fixup is made. */
926:
927: static int
928: expand_fixup (tree_label, rtl_label, last_insn)
929: tree tree_label;
930: rtx rtl_label;
931: rtx last_insn;
932: {
933: struct nesting *block, *end_block;
934:
935: /* See if we can recognize which block the label will be output in.
936: This is possible in some very common cases.
937: If we succeed, set END_BLOCK to that block.
938: Otherwise, set it to 0. */
939:
940: if (cond_stack
941: && (rtl_label == cond_stack->data.cond.endif_label
942: || rtl_label == cond_stack->data.cond.next_label))
943: end_block = cond_stack;
944: /* If we are in a loop, recognize certain labels which
945: are likely targets. This reduces the number of fixups
946: we need to create. */
947: else if (loop_stack
948: && (rtl_label == loop_stack->data.loop.start_label
949: || rtl_label == loop_stack->data.loop.end_label
950: || rtl_label == loop_stack->data.loop.continue_label))
951: end_block = loop_stack;
952: else
953: end_block = 0;
954:
955: /* Now set END_BLOCK to the binding level to which we will return. */
956:
957: if (end_block)
958: {
959: struct nesting *next_block = end_block->all;
960: block = block_stack;
961:
962: /* First see if the END_BLOCK is inside the innermost binding level.
963: If so, then no cleanups or stack levels are relevant. */
964: while (next_block && next_block != block)
965: next_block = next_block->all;
966:
967: if (next_block)
968: return 0;
969:
970: /* Otherwise, set END_BLOCK to the innermost binding level
971: which is outside the relevant control-structure nesting. */
972: next_block = block_stack->next;
973: for (block = block_stack; block != end_block; block = block->all)
974: if (block == next_block)
975: next_block = next_block->next;
976: end_block = next_block;
977: }
978:
979: /* Does any containing block have a stack level or cleanups?
980: If not, no fixup is needed, and that is the normal case
981: (the only case, for standard C). */
982: for (block = block_stack; block != end_block; block = block->next)
983: if (block->data.block.stack_level != 0
984: || block->data.block.cleanups != 0)
985: break;
986:
987: if (block != end_block)
988: {
989: /* Ok, a fixup is needed. Add a fixup to the list of such. */
990: struct goto_fixup *fixup
991: = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
992: /* In case an old stack level is restored, make sure that comes
993: after any pending stack adjust. */
994: /* ?? If the fixup isn't to come at the present position,
995: doing the stack adjust here isn't useful. Doing it with our
996: settings at that location isn't useful either. Let's hope
997: someone does it! */
998: if (last_insn == 0)
999: do_pending_stack_adjust ();
1000: fixup->target = tree_label;
1001: fixup->target_rtl = rtl_label;
1002:
1003: /* Create a BLOCK node and a corresponding matched set of
1004: NOTE_INSN_BEGIN_BLOCK and NOTE_INSN_END_BLOCK notes at
1005: this point. The notes will encapsulate any and all fixup
1006: code which we might later insert at this point in the insn
1007: stream. Also, the BLOCK node will be the parent (i.e. the
1008: `SUPERBLOCK') of any other BLOCK nodes which we might create
1009: later on when we are expanding the fixup code. */
1010:
1011: {
1012: register rtx original_before_jump
1013: = last_insn ? last_insn : get_last_insn ();
1014:
1015: start_sequence ();
1016: pushlevel (0);
1017: fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
1018: last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
1019: fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
1020: end_sequence ();
1021: emit_insns_after (fixup->before_jump, original_before_jump);
1022: }
1023:
1024: fixup->block_start_count = block_start_count;
1025: fixup->stack_level = 0;
1026: fixup->cleanup_list_list
1027: = (((block->data.block.outer_cleanups
1028: #if 0
1029: && block->data.block.outer_cleanups != empty_cleanup_list
1030: #endif
1031: )
1032: || block->data.block.cleanups)
1033: ? tree_cons (NULL_TREE, block->data.block.cleanups,
1034: block->data.block.outer_cleanups)
1035: : 0);
1036: fixup->next = goto_fixup_chain;
1037: goto_fixup_chain = fixup;
1038: }
1039:
1040: return block != 0;
1041: }
1042:
1043:
1044: /* Generate bytecode jump with OPCODE to a fixup routine that links to LABEL.
1045: Make the fixup restore the stack level to STACK_LEVEL. */
1046:
1047: static void
1048: bc_expand_fixup (opcode, label, stack_level)
1049: enum bytecode_opcode opcode;
1050: struct bc_label *label;
1051: int stack_level;
1052: {
1053: struct goto_fixup *fixup
1054: = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
1055:
1056: fixup->label = bc_get_bytecode_label ();
1057: fixup->bc_target = label;
1058: fixup->bc_stack_level = stack_level;
1059: fixup->bc_handled = FALSE;
1060:
1061: fixup->next = goto_fixup_chain;
1062: goto_fixup_chain = fixup;
1063:
1064: /* Insert a jump to the fixup code */
1065: bc_emit_bytecode (opcode);
1066: bc_emit_bytecode_labelref (fixup->label);
1067:
1068: #ifdef DEBUG_PRINT_CODE
1069: fputc ('\n', stderr);
1070: #endif
1071: }
1072:
1073:
1074: /* When exiting a binding contour, process all pending gotos requiring fixups.
1075: THISBLOCK is the structure that describes the block being exited.
1076: STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1077: CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1078: FIRST_INSN is the insn that began this contour.
1079:
1080: Gotos that jump out of this contour must restore the
1081: stack level and do the cleanups before actually jumping.
1082:
1083: DONT_JUMP_IN nonzero means report error there is a jump into this
1084: contour from before the beginning of the contour.
1085: This is also done if STACK_LEVEL is nonzero. */
1086:
1087: void
1088: fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1089: struct nesting *thisblock;
1090: rtx stack_level;
1091: tree cleanup_list;
1092: rtx first_insn;
1093: int dont_jump_in;
1094: {
1095: register struct goto_fixup *f, *prev;
1096:
1097: if (output_bytecode)
1098: {
1099: bc_fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in);
1100: return;
1101: }
1102:
1103: /* F is the fixup we are considering; PREV is the previous one. */
1104: /* We run this loop in two passes so that cleanups of exited blocks
1105: are run first, and blocks that are exited are marked so
1106: afterwards. */
1107:
1108: for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1109: {
1110: /* Test for a fixup that is inactive because it is already handled. */
1111: if (f->before_jump == 0)
1112: {
1113: /* Delete inactive fixup from the chain, if that is easy to do. */
1114: if (prev != 0)
1115: prev->next = f->next;
1116: }
1117: /* Has this fixup's target label been defined?
1118: If so, we can finalize it. */
1119: else if (PREV_INSN (f->target_rtl) != 0)
1120: {
1121: register rtx cleanup_insns;
1122:
1123: /* Get the first non-label after the label
1124: this goto jumps to. If that's before this scope begins,
1125: we don't have a jump into the scope. */
1126: rtx after_label = f->target_rtl;
1127: while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
1128: after_label = NEXT_INSN (after_label);
1129:
1130: /* If this fixup jumped into this contour from before the beginning
1131: of this contour, report an error. */
1132: /* ??? Bug: this does not detect jumping in through intermediate
1133: blocks that have stack levels or cleanups.
1134: It detects only a problem with the innermost block
1135: around the label. */
1136: if (f->target != 0
1137: && (dont_jump_in || stack_level || cleanup_list)
1138: /* If AFTER_LABEL is 0, it means the jump goes to the end
1139: of the rtl, which means it jumps into this scope. */
1140: && (after_label == 0
1141: || INSN_UID (first_insn) < INSN_UID (after_label))
1142: && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1143: && ! DECL_REGISTER (f->target))
1144: {
1145: error_with_decl (f->target,
1146: "label `%s' used before containing binding contour");
1147: /* Prevent multiple errors for one label. */
1148: DECL_REGISTER (f->target) = 1;
1149: }
1150:
1151: /* We will expand the cleanups into a sequence of their own and
1152: then later on we will attach this new sequence to the insn
1153: stream just ahead of the actual jump insn. */
1154:
1155: start_sequence ();
1156:
1157: /* Temporarily restore the lexical context where we will
1158: logically be inserting the fixup code. We do this for the
1159: sake of getting the debugging information right. */
1160:
1161: pushlevel (0);
1162: set_block (f->context);
1163:
1164: /* Expand the cleanups for blocks this jump exits. */
1165: if (f->cleanup_list_list)
1166: {
1167: tree lists;
1168: for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1169: /* Marked elements correspond to blocks that have been closed.
1170: Do their cleanups. */
1171: if (TREE_ADDRESSABLE (lists)
1172: && TREE_VALUE (lists) != 0)
1173: {
1174: expand_cleanups (TREE_VALUE (lists), 0);
1175: /* Pop any pushes done in the cleanups,
1176: in case function is about to return. */
1177: do_pending_stack_adjust ();
1178: }
1179: }
1180:
1181: /* Restore stack level for the biggest contour that this
1182: jump jumps out of. */
1183: if (f->stack_level)
1184: emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1185:
1186: /* Finish up the sequence containing the insns which implement the
1187: necessary cleanups, and then attach that whole sequence to the
1188: insn stream just ahead of the actual jump insn. Attaching it
1189: at that point insures that any cleanups which are in fact
1190: implicit C++ object destructions (which must be executed upon
1191: leaving the block) appear (to the debugger) to be taking place
1192: in an area of the generated code where the object(s) being
1193: destructed are still "in scope". */
1194:
1195: cleanup_insns = get_insns ();
1196: poplevel (1, 0, 0);
1197:
1198: end_sequence ();
1199: emit_insns_after (cleanup_insns, f->before_jump);
1200:
1201:
1202: f->before_jump = 0;
1203: }
1204: }
1205:
1206: /* Mark the cleanups of exited blocks so that they are executed
1207: by the code above. */
1208: for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1209: if (f->before_jump != 0
1210: && PREV_INSN (f->target_rtl) == 0
1211: /* Label has still not appeared. If we are exiting a block with
1212: a stack level to restore, that started before the fixup,
1213: mark this stack level as needing restoration
1214: when the fixup is later finalized.
1215: Also mark the cleanup_list_list element for F
1216: that corresponds to this block, so that ultimately
1217: this block's cleanups will be executed by the code above. */
1218: && thisblock != 0
1219: /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared,
1220: it means the label is undefined. That's erroneous, but possible. */
1221: && (thisblock->data.block.block_start_count
1222: <= f->block_start_count))
1223: {
1224: tree lists = f->cleanup_list_list;
1225: for (; lists; lists = TREE_CHAIN (lists))
1226: /* If the following elt. corresponds to our containing block
1227: then the elt. must be for this block. */
1228: if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1229: TREE_ADDRESSABLE (lists) = 1;
1230:
1231: if (stack_level)
1232: f->stack_level = stack_level;
1233: }
1234: }
1235:
1236:
1237: /* When exiting a binding contour, process all pending gotos requiring fixups.
1238: Note: STACK_DEPTH is not altered.
1239:
1240: The arguments are currently not used in the bytecode compiler, but we may need
1241: them one day for languages other than C.
1242:
1243: THISBLOCK is the structure that describes the block being exited.
1244: STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1245: CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1246: FIRST_INSN is the insn that began this contour.
1247:
1248: Gotos that jump out of this contour must restore the
1249: stack level and do the cleanups before actually jumping.
1250:
1251: DONT_JUMP_IN nonzero means report error there is a jump into this
1252: contour from before the beginning of the contour.
1253: This is also done if STACK_LEVEL is nonzero. */
1254:
1255: static void
1256: bc_fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1257: struct nesting *thisblock;
1258: int stack_level;
1259: tree cleanup_list;
1260: rtx first_insn;
1261: int dont_jump_in;
1262: {
1263: register struct goto_fixup *f, *prev;
1264: int saved_stack_depth;
1265:
1266: /* F is the fixup we are considering; PREV is the previous one. */
1267:
1268: for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1269: {
1270: /* Test for a fixup that is inactive because it is already handled. */
1271: if (f->before_jump == 0)
1272: {
1273: /* Delete inactive fixup from the chain, if that is easy to do. */
1274: if (prev)
1275: prev->next = f->next;
1276: }
1277:
1278: /* Emit code to restore the stack and continue */
1279: bc_emit_bytecode_labeldef (f->label);
1280:
1281: /* Save stack_depth across call, since bc_adjust_stack () will alter
1282: the perceived stack depth via the instructions generated. */
1283:
1284: if (f->bc_stack_level >= 0)
1285: {
1286: saved_stack_depth = stack_depth;
1287: bc_adjust_stack (stack_depth - f->bc_stack_level);
1288: stack_depth = saved_stack_depth;
1289: }
1290:
1291: bc_emit_bytecode (jump);
1292: bc_emit_bytecode_labelref (f->bc_target);
1293:
1294: #ifdef DEBUG_PRINT_CODE
1295: fputc ('\n', stderr);
1296: #endif
1297: }
1298:
1299: goto_fixup_chain = NULL;
1300: }
1301:
1302: /* Generate RTL for an asm statement (explicit assembler code).
1303: BODY is a STRING_CST node containing the assembler code text,
1304: or an ADDR_EXPR containing a STRING_CST. */
1305:
1306: void
1307: expand_asm (body)
1308: tree body;
1309: {
1310: if (output_bytecode)
1311: {
1312: error ("`asm' is illegal when generating bytecode");
1313: return;
1314: }
1315:
1316: if (TREE_CODE (body) == ADDR_EXPR)
1317: body = TREE_OPERAND (body, 0);
1318:
1319: emit_insn (gen_rtx (ASM_INPUT, VOIDmode,
1320: TREE_STRING_POINTER (body)));
1321: last_expr_type = 0;
1322: }
1323:
1324: /* Generate RTL for an asm statement with arguments.
1325: STRING is the instruction template.
1326: OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1327: Each output or input has an expression in the TREE_VALUE and
1328: a constraint-string in the TREE_PURPOSE.
1329: CLOBBERS is a list of STRING_CST nodes each naming a hard register
1330: that is clobbered by this insn.
1331:
1332: Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1333: Some elements of OUTPUTS may be replaced with trees representing temporary
1334: values. The caller should copy those temporary values to the originally
1335: specified lvalues.
1336:
1337: VOL nonzero means the insn is volatile; don't optimize it. */
1338:
1339: void
1340: expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1341: tree string, outputs, inputs, clobbers;
1342: int vol;
1343: char *filename;
1344: int line;
1345: {
1346: rtvec argvec, constraints;
1347: rtx body;
1348: int ninputs = list_length (inputs);
1349: int noutputs = list_length (outputs);
1350: int nclobbers;
1351: tree tail;
1352: register int i;
1353: /* Vector of RTX's of evaluated output operands. */
1354: rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1355: /* The insn we have emitted. */
1356: rtx insn;
1357:
1358: if (output_bytecode)
1359: {
1360: error ("`asm' is illegal when generating bytecode");
1361: return;
1362: }
1363:
1364: /* Count the number of meaningful clobbered registers, ignoring what
1365: we would ignore later. */
1366: nclobbers = 0;
1367: for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1368: {
1369: char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1370: i = decode_reg_name (regname);
1371: if (i >= 0 || i == -4)
1372: ++nclobbers;
1373: }
1374:
1375: last_expr_type = 0;
1376:
1377: for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1378: {
1379: tree val = TREE_VALUE (tail);
1380: tree val1;
1381: int j;
1382: int found_equal;
1383:
1384: /* If there's an erroneous arg, emit no insn. */
1385: if (TREE_TYPE (val) == error_mark_node)
1386: return;
1387:
1388: /* Make sure constraint has `=' and does not have `+'. */
1389:
1390: found_equal = 0;
1391: for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1392: {
1393: if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1394: {
1395: error ("output operand constraint contains `+'");
1396: return;
1397: }
1398: if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '=')
1399: found_equal = 1;
1400: }
1401: if (! found_equal)
1402: {
1403: error ("output operand constraint lacks `='");
1404: return;
1405: }
1406:
1407: /* If an output operand is not a variable or indirect ref,
1408: or a part of one,
1409: create a SAVE_EXPR which is a pseudo-reg
1410: to act as an intermediate temporary.
1411: Make the asm insn write into that, then copy it to
1412: the real output operand. */
1413:
1414: while (TREE_CODE (val) == COMPONENT_REF
1415: || TREE_CODE (val) == ARRAY_REF)
1416: val = TREE_OPERAND (val, 0);
1417:
1418: if (TREE_CODE (val) != VAR_DECL
1419: && TREE_CODE (val) != PARM_DECL
1420: && TREE_CODE (val) != INDIRECT_REF)
1421: {
1422: TREE_VALUE (tail) = save_expr (TREE_VALUE (tail));
1423: /* If it's a constant, print error now so don't crash later. */
1424: if (TREE_CODE (TREE_VALUE (tail)) != SAVE_EXPR)
1425: {
1426: error ("invalid output in `asm'");
1427: return;
1428: }
1429: }
1430:
1431: output_rtx[i] = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1432: }
1433:
1434: if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1435: {
1436: error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1437: return;
1438: }
1439:
1440: /* Make vectors for the expression-rtx and constraint strings. */
1441:
1442: argvec = rtvec_alloc (ninputs);
1443: constraints = rtvec_alloc (ninputs);
1444:
1445: body = gen_rtx (ASM_OPERANDS, VOIDmode,
1446: TREE_STRING_POINTER (string), "", 0, argvec, constraints,
1447: filename, line);
1448: MEM_VOLATILE_P (body) = vol;
1449:
1450: /* Eval the inputs and put them into ARGVEC.
1451: Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1452:
1453: i = 0;
1454: for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1455: {
1456: int j;
1457:
1458: /* If there's an erroneous arg, emit no insn,
1459: because the ASM_INPUT would get VOIDmode
1460: and that could cause a crash in reload. */
1461: if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1462: return;
1463: if (TREE_PURPOSE (tail) == NULL_TREE)
1464: {
1465: error ("hard register `%s' listed as input operand to `asm'",
1466: TREE_STRING_POINTER (TREE_VALUE (tail)) );
1467: return;
1468: }
1469:
1470: /* Make sure constraint has neither `=' nor `+'. */
1471:
1472: for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1473: if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '='
1474: || TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1475: {
1476: error ("input operand constraint contains `%c'",
1477: TREE_STRING_POINTER (TREE_PURPOSE (tail))[j]);
1478: return;
1479: }
1480:
1481: XVECEXP (body, 3, i) /* argvec */
1482: = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1483: XVECEXP (body, 4, i) /* constraints */
1484: = gen_rtx (ASM_INPUT, TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1485: TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1486: i++;
1487: }
1488:
1489: /* Protect all the operands from the queue,
1490: now that they have all been evaluated. */
1491:
1492: for (i = 0; i < ninputs; i++)
1493: XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1494:
1495: for (i = 0; i < noutputs; i++)
1496: output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1497:
1498: /* Now, for each output, construct an rtx
1499: (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1500: ARGVEC CONSTRAINTS))
1501: If there is more than one, put them inside a PARALLEL. */
1502:
1503: if (noutputs == 1 && nclobbers == 0)
1504: {
1505: XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1506: insn = emit_insn (gen_rtx (SET, VOIDmode, output_rtx[0], body));
1507: }
1508: else if (noutputs == 0 && nclobbers == 0)
1509: {
1510: /* No output operands: put in a raw ASM_OPERANDS rtx. */
1511: insn = emit_insn (body);
1512: }
1513: else
1514: {
1515: rtx obody = body;
1516: int num = noutputs;
1517: if (num == 0) num = 1;
1518: body = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (num + nclobbers));
1519:
1520: /* For each output operand, store a SET. */
1521:
1522: for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1523: {
1524: XVECEXP (body, 0, i)
1525: = gen_rtx (SET, VOIDmode,
1526: output_rtx[i],
1527: gen_rtx (ASM_OPERANDS, VOIDmode,
1528: TREE_STRING_POINTER (string),
1529: TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1530: i, argvec, constraints,
1531: filename, line));
1532: MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1533: }
1534:
1535: /* If there are no outputs (but there are some clobbers)
1536: store the bare ASM_OPERANDS into the PARALLEL. */
1537:
1538: if (i == 0)
1539: XVECEXP (body, 0, i++) = obody;
1540:
1541: /* Store (clobber REG) for each clobbered register specified. */
1542:
1543: for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1544: {
1545: char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1546: int j = decode_reg_name (regname);
1547:
1548: if (j < 0)
1549: {
1550: if (j == -3) /* `cc', which is not a register */
1551: continue;
1552:
1553: if (j == -4) /* `memory', don't cache memory across asm */
1554: {
1555: XVECEXP (body, 0, i++)
1556: = gen_rtx (CLOBBER, VOIDmode,
1557: gen_rtx (MEM, QImode,
1558: gen_rtx (SCRATCH, VOIDmode, 0)));
1559: continue;
1560: }
1561:
1562: error ("unknown register name `%s' in `asm'", regname);
1563: return;
1564: }
1565:
1566: /* Use QImode since that's guaranteed to clobber just one reg. */
1567: XVECEXP (body, 0, i++)
1568: = gen_rtx (CLOBBER, VOIDmode, gen_rtx (REG, QImode, j));
1569: }
1570:
1571: insn = emit_insn (body);
1572: }
1573:
1574: free_temp_slots ();
1575: }
1576:
1577: /* Generate RTL to evaluate the expression EXP
1578: and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1579:
1580: void
1581: expand_expr_stmt (exp)
1582: tree exp;
1583: {
1584: if (output_bytecode)
1585: {
1586: int org_stack_depth = stack_depth;
1587:
1588: bc_expand_expr (exp);
1589:
1590: /* Restore stack depth */
1591: if (stack_depth < org_stack_depth)
1592: abort ();
1593:
1594: bc_emit_instruction (drop);
1595:
1596: last_expr_type = TREE_TYPE (exp);
1597: return;
1598: }
1599:
1600: /* If -W, warn about statements with no side effects,
1601: except for an explicit cast to void (e.g. for assert()), and
1602: except inside a ({...}) where they may be useful. */
1603: if (expr_stmts_for_value == 0 && exp != error_mark_node)
1604: {
1605: if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1606: && !(TREE_CODE (exp) == CONVERT_EXPR
1607: && TREE_TYPE (exp) == void_type_node))
1608: warning_with_file_and_line (emit_filename, emit_lineno,
1609: "statement with no effect");
1610: else if (warn_unused)
1611: warn_if_unused_value (exp);
1612: }
1613: last_expr_type = TREE_TYPE (exp);
1614: if (! flag_syntax_only)
1615: last_expr_value = expand_expr (exp,
1616: (expr_stmts_for_value
1617: ? NULL_RTX : const0_rtx),
1618: VOIDmode, 0);
1619:
1620: /* If all we do is reference a volatile value in memory,
1621: copy it to a register to be sure it is actually touched. */
1622: if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1623: && TREE_THIS_VOLATILE (exp))
1624: {
1625: if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1626: ;
1627: else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1628: copy_to_reg (last_expr_value);
1629: else
1630: {
1631: rtx lab = gen_label_rtx ();
1632:
1633: /* Compare the value with itself to reference it. */
1634: emit_cmp_insn (last_expr_value, last_expr_value, EQ,
1635: expand_expr (TYPE_SIZE (last_expr_type),
1636: NULL_RTX, VOIDmode, 0),
1637: BLKmode, 0,
1638: TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT);
1639: emit_jump_insn ((*bcc_gen_fctn[(int) EQ]) (lab));
1640: emit_label (lab);
1641: }
1642: }
1643:
1644: /* If this expression is part of a ({...}) and is in memory, we may have
1645: to preserve temporaries. */
1646: preserve_temp_slots (last_expr_value);
1647:
1648: /* Free any temporaries used to evaluate this expression. Any temporary
1649: used as a result of this expression will already have been preserved
1650: above. */
1651: free_temp_slots ();
1652:
1653: emit_queue ();
1654: }
1655:
1656: /* Warn if EXP contains any computations whose results are not used.
1657: Return 1 if a warning is printed; 0 otherwise. */
1658:
1659: static int
1660: warn_if_unused_value (exp)
1661: tree exp;
1662: {
1663: if (TREE_USED (exp))
1664: return 0;
1665:
1666: switch (TREE_CODE (exp))
1667: {
1668: case PREINCREMENT_EXPR:
1669: case POSTINCREMENT_EXPR:
1670: case PREDECREMENT_EXPR:
1671: case POSTDECREMENT_EXPR:
1672: case MODIFY_EXPR:
1673: case INIT_EXPR:
1674: case TARGET_EXPR:
1675: case CALL_EXPR:
1676: case METHOD_CALL_EXPR:
1677: case RTL_EXPR:
1678: case WITH_CLEANUP_EXPR:
1679: case EXIT_EXPR:
1680: /* We don't warn about COND_EXPR because it may be a useful
1681: construct if either arm contains a side effect. */
1682: case COND_EXPR:
1683: return 0;
1684:
1685: case BIND_EXPR:
1686: /* For a binding, warn if no side effect within it. */
1687: return warn_if_unused_value (TREE_OPERAND (exp, 1));
1688:
1689: case TRUTH_ORIF_EXPR:
1690: case TRUTH_ANDIF_EXPR:
1691: /* In && or ||, warn if 2nd operand has no side effect. */
1692: return warn_if_unused_value (TREE_OPERAND (exp, 1));
1693:
1694: case COMPOUND_EXPR:
1695: if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1696: return 1;
1697: /* Let people do `(foo (), 0)' without a warning. */
1698: if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1699: return 0;
1700: return warn_if_unused_value (TREE_OPERAND (exp, 1));
1701:
1702: case NOP_EXPR:
1703: case CONVERT_EXPR:
1704: case NON_LVALUE_EXPR:
1705: /* Don't warn about values cast to void. */
1706: if (TREE_TYPE (exp) == void_type_node)
1707: return 0;
1708: /* Don't warn about conversions not explicit in the user's program. */
1709: if (TREE_NO_UNUSED_WARNING (exp))
1710: return 0;
1711: /* Assignment to a cast usually results in a cast of a modify.
1712: Don't complain about that. There can be an arbitrary number of
1713: casts before the modify, so we must loop until we find the first
1714: non-cast expression and then test to see if that is a modify. */
1715: {
1716: tree tem = TREE_OPERAND (exp, 0);
1717:
1718: while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1719: tem = TREE_OPERAND (tem, 0);
1720:
1721: if (TREE_CODE (tem) == MODIFY_EXPR)
1722: return 0;
1723: }
1724: /* ... fall through ... */
1725:
1726: default:
1727: /* Referencing a volatile value is a side effect, so don't warn. */
1728: if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1729: || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1730: && TREE_THIS_VOLATILE (exp))
1731: return 0;
1732: warning_with_file_and_line (emit_filename, emit_lineno,
1733: "value computed is not used");
1734: return 1;
1735: }
1736: }
1737:
1738: /* Clear out the memory of the last expression evaluated. */
1739:
1740: void
1741: clear_last_expr ()
1742: {
1743: last_expr_type = 0;
1744: }
1745:
1746: /* Begin a statement which will return a value.
1747: Return the RTL_EXPR for this statement expr.
1748: The caller must save that value and pass it to expand_end_stmt_expr. */
1749:
1750: tree
1751: expand_start_stmt_expr ()
1752: {
1753: int momentary;
1754: tree t;
1755:
1756: /* When generating bytecode just note down the stack depth */
1757: if (output_bytecode)
1758: return (build_int_2 (stack_depth, 0));
1759:
1760: /* Make the RTL_EXPR node temporary, not momentary,
1761: so that rtl_expr_chain doesn't become garbage. */
1762: momentary = suspend_momentary ();
1763: t = make_node (RTL_EXPR);
1764: resume_momentary (momentary);
1765: start_sequence_for_rtl_expr (t);
1766: NO_DEFER_POP;
1767: expr_stmts_for_value++;
1768: return t;
1769: }
1770:
1771: /* Restore the previous state at the end of a statement that returns a value.
1772: Returns a tree node representing the statement's value and the
1773: insns to compute the value.
1774:
1775: The nodes of that expression have been freed by now, so we cannot use them.
1776: But we don't want to do that anyway; the expression has already been
1777: evaluated and now we just want to use the value. So generate a RTL_EXPR
1778: with the proper type and RTL value.
1779:
1780: If the last substatement was not an expression,
1781: return something with type `void'. */
1782:
1783: tree
1784: expand_end_stmt_expr (t)
1785: tree t;
1786: {
1787: if (output_bytecode)
1788: {
1789: int i;
1790: tree t;
1791:
1792:
1793: /* At this point, all expressions have been evaluated in order.
1794: However, all expression values have been popped when evaluated,
1795: which means we have to recover the last expression value. This is
1796: the last value removed by means of a `drop' instruction. Instead
1797: of adding code to inhibit dropping the last expression value, it
1798: is here recovered by undoing the `drop'. Since `drop' is
1799: equivalent to `adjustackSI [1]', it can be undone with `adjstackSI
1800: [-1]'. */
1801:
1802: bc_adjust_stack (-1);
1803:
1804: if (!last_expr_type)
1805: last_expr_type = void_type_node;
1806:
1807: t = make_node (RTL_EXPR);
1808: TREE_TYPE (t) = last_expr_type;
1809: RTL_EXPR_RTL (t) = NULL;
1810: RTL_EXPR_SEQUENCE (t) = NULL;
1811:
1812: /* Don't consider deleting this expr or containing exprs at tree level. */
1813: TREE_THIS_VOLATILE (t) = 1;
1814:
1815: last_expr_type = 0;
1816: return t;
1817: }
1818:
1819: OK_DEFER_POP;
1820:
1821: if (last_expr_type == 0)
1822: {
1823: last_expr_type = void_type_node;
1824: last_expr_value = const0_rtx;
1825: }
1826: else if (last_expr_value == 0)
1827: /* There are some cases where this can happen, such as when the
1828: statement is void type. */
1829: last_expr_value = const0_rtx;
1830: else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1831: /* Remove any possible QUEUED. */
1832: last_expr_value = protect_from_queue (last_expr_value, 0);
1833:
1834: emit_queue ();
1835:
1836: TREE_TYPE (t) = last_expr_type;
1837: RTL_EXPR_RTL (t) = last_expr_value;
1838: RTL_EXPR_SEQUENCE (t) = get_insns ();
1839:
1840: rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1841:
1842: end_sequence ();
1843:
1844: /* Don't consider deleting this expr or containing exprs at tree level. */
1845: TREE_SIDE_EFFECTS (t) = 1;
1846: /* Propagate volatility of the actual RTL expr. */
1847: TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1848:
1849: last_expr_type = 0;
1850: expr_stmts_for_value--;
1851:
1852: return t;
1853: }
1854:
1855: /* The exception handling nesting looks like this:
1856:
1857: <-- Level N-1
1858: { <-- exception handler block
1859: <-- Level N
1860: <-- in an exception handler
1861: { <-- try block
1862: : <-- in a TRY block
1863: : <-- in an exception handler
1864: :
1865: }
1866:
1867: { <-- except block
1868: : <-- in an except block
1869: : <-- in an exception handler
1870: :
1871: }
1872:
1873: }
1874: */
1875:
1876: /* Return nonzero iff in a try block at level LEVEL. */
1877:
1878: int
1879: in_try_block (level)
1880: int level;
1881: {
1882: struct nesting *n = except_stack;
1883: while (1)
1884: {
1885: while (n && n->data.except_stmt.after_label != 0)
1886: n = n->next;
1887: if (n == 0)
1888: return 0;
1889: if (level == 0)
1890: return n != 0;
1891: level--;
1892: n = n->next;
1893: }
1894: }
1895:
1896: /* Return nonzero iff in an except block at level LEVEL. */
1897:
1898: int
1899: in_except_block (level)
1900: int level;
1901: {
1902: struct nesting *n = except_stack;
1903: while (1)
1904: {
1905: while (n && n->data.except_stmt.after_label == 0)
1906: n = n->next;
1907: if (n == 0)
1908: return 0;
1909: if (level == 0)
1910: return n != 0;
1911: level--;
1912: n = n->next;
1913: }
1914: }
1915:
1916: /* Return nonzero iff in an exception handler at level LEVEL. */
1917:
1918: int
1919: in_exception_handler (level)
1920: int level;
1921: {
1922: struct nesting *n = except_stack;
1923: while (n && level--)
1924: n = n->next;
1925: return n != 0;
1926: }
1927:
1928: /* Record the fact that the current exception nesting raises
1929: exception EX. If not in an exception handler, return 0. */
1930: int
1931: expand_raise (ex)
1932: tree ex;
1933: {
1934: tree *raises_ptr;
1935:
1936: if (except_stack == 0)
1937: return 0;
1938: raises_ptr = &except_stack->data.except_stmt.raised;
1939: if (! value_member (ex, *raises_ptr))
1940: *raises_ptr = tree_cons (NULL_TREE, ex, *raises_ptr);
1941: return 1;
1942: }
1943:
1944: /* Generate RTL for the start of a try block.
1945:
1946: TRY_CLAUSE is the condition to test to enter the try block. */
1947:
1948: void
1949: expand_start_try (try_clause, exitflag, escapeflag)
1950: tree try_clause;
1951: int exitflag;
1952: int escapeflag;
1953: {
1954: struct nesting *thishandler = ALLOC_NESTING ();
1955:
1956: /* Make an entry on cond_stack for the cond we are entering. */
1957:
1958: thishandler->next = except_stack;
1959: thishandler->all = nesting_stack;
1960: thishandler->depth = ++nesting_depth;
1961: thishandler->data.except_stmt.raised = 0;
1962: thishandler->data.except_stmt.handled = 0;
1963: thishandler->data.except_stmt.first_insn = get_insns ();
1964: thishandler->data.except_stmt.except_label = gen_label_rtx ();
1965: thishandler->data.except_stmt.unhandled_label = 0;
1966: thishandler->data.except_stmt.after_label = 0;
1967: thishandler->data.except_stmt.escape_label
1968: = escapeflag ? thishandler->data.except_stmt.except_label : 0;
1969: thishandler->exit_label = exitflag ? gen_label_rtx () : 0;
1970: except_stack = thishandler;
1971: nesting_stack = thishandler;
1972:
1973: do_jump (try_clause, thishandler->data.except_stmt.except_label, NULL_RTX);
1974: }
1975:
1976: /* End of a TRY block. Nothing to do for now. */
1977:
1978: void
1979: expand_end_try ()
1980: {
1981: except_stack->data.except_stmt.after_label = gen_label_rtx ();
1982: expand_goto_internal (NULL_TREE, except_stack->data.except_stmt.after_label,
1983: NULL_RTX);
1984: }
1985:
1986: /* Start an `except' nesting contour.
1987: EXITFLAG says whether this contour should be able to `exit' something.
1988: ESCAPEFLAG says whether this contour should be escapable. */
1989:
1990: void
1991: expand_start_except (exitflag, escapeflag)
1992: int exitflag;
1993: int escapeflag;
1994: {
1995: if (exitflag)
1996: {
1997: struct nesting *n;
1998: /* An `exit' from catch clauses goes out to next exit level,
1999: if there is one. Otherwise, it just goes to the end
2000: of the construct. */
2001: for (n = except_stack->next; n; n = n->next)
2002: if (n->exit_label != 0)
2003: {
2004: except_stack->exit_label = n->exit_label;
2005: break;
2006: }
2007: if (n == 0)
2008: except_stack->exit_label = except_stack->data.except_stmt.after_label;
2009: }
2010: if (escapeflag)
2011: {
2012: struct nesting *n;
2013: /* An `escape' from catch clauses goes out to next escape level,
2014: if there is one. Otherwise, it just goes to the end
2015: of the construct. */
2016: for (n = except_stack->next; n; n = n->next)
2017: if (n->data.except_stmt.escape_label != 0)
2018: {
2019: except_stack->data.except_stmt.escape_label
2020: = n->data.except_stmt.escape_label;
2021: break;
2022: }
2023: if (n == 0)
2024: except_stack->data.except_stmt.escape_label
2025: = except_stack->data.except_stmt.after_label;
2026: }
2027: do_pending_stack_adjust ();
2028: emit_label (except_stack->data.except_stmt.except_label);
2029: }
2030:
2031: /* Generate code to `escape' from an exception contour. This
2032: is like `exiting', but does not conflict with constructs which
2033: use `exit_label'.
2034:
2035: Return nonzero if this contour is escapable, otherwise
2036: return zero, and language-specific code will emit the
2037: appropriate error message. */
2038: int
2039: expand_escape_except ()
2040: {
2041: struct nesting *n;
2042: last_expr_type = 0;
2043: for (n = except_stack; n; n = n->next)
2044: if (n->data.except_stmt.escape_label != 0)
2045: {
2046: expand_goto_internal (NULL_TREE,
2047: n->data.except_stmt.escape_label, NULL_RTX);
2048: return 1;
2049: }
2050:
2051: return 0;
2052: }
2053:
2054: /* Finish processing and `except' contour.
2055: Culls out all exceptions which might be raise but not
2056: handled, and returns the list to the caller.
2057: Language-specific code is responsible for dealing with these
2058: exceptions. */
2059:
2060: tree
2061: expand_end_except ()
2062: {
2063: struct nesting *n;
2064: tree raised = NULL_TREE;
2065:
2066: do_pending_stack_adjust ();
2067: emit_label (except_stack->data.except_stmt.after_label);
2068:
2069: n = except_stack->next;
2070: if (n)
2071: {
2072: /* Propagate exceptions raised but not handled to next
2073: highest level. */
2074: tree handled = except_stack->data.except_stmt.raised;
2075: if (handled != void_type_node)
2076: {
2077: tree prev = NULL_TREE;
2078: raised = except_stack->data.except_stmt.raised;
2079: while (handled)
2080: {
2081: tree this_raise;
2082: for (this_raise = raised, prev = 0; this_raise;
2083: this_raise = TREE_CHAIN (this_raise))
2084: {
2085: if (value_member (TREE_VALUE (this_raise), handled))
2086: {
2087: if (prev)
2088: TREE_CHAIN (prev) = TREE_CHAIN (this_raise);
2089: else
2090: {
2091: raised = TREE_CHAIN (raised);
2092: if (raised == NULL_TREE)
2093: goto nada;
2094: }
2095: }
2096: else
2097: prev = this_raise;
2098: }
2099: handled = TREE_CHAIN (handled);
2100: }
2101: if (prev == NULL_TREE)
2102: prev = raised;
2103: if (prev)
2104: TREE_CHAIN (prev) = n->data.except_stmt.raised;
2105: nada:
2106: n->data.except_stmt.raised = raised;
2107: }
2108: }
2109:
2110: POPSTACK (except_stack);
2111: last_expr_type = 0;
2112: return raised;
2113: }
2114:
2115: /* Record that exception EX is caught by this exception handler.
2116: Return nonzero if in exception handling construct, otherwise return 0. */
2117: int
2118: expand_catch (ex)
2119: tree ex;
2120: {
2121: tree *raises_ptr;
2122:
2123: if (except_stack == 0)
2124: return 0;
2125: raises_ptr = &except_stack->data.except_stmt.handled;
2126: if (*raises_ptr != void_type_node
2127: && ex != NULL_TREE
2128: && ! value_member (ex, *raises_ptr))
2129: *raises_ptr = tree_cons (NULL_TREE, ex, *raises_ptr);
2130: return 1;
2131: }
2132:
2133: /* Record that this exception handler catches all exceptions.
2134: Return nonzero if in exception handling construct, otherwise return 0. */
2135:
2136: int
2137: expand_catch_default ()
2138: {
2139: if (except_stack == 0)
2140: return 0;
2141: except_stack->data.except_stmt.handled = void_type_node;
2142: return 1;
2143: }
2144:
2145: int
2146: expand_end_catch ()
2147: {
2148: if (except_stack == 0 || except_stack->data.except_stmt.after_label == 0)
2149: return 0;
2150: expand_goto_internal (NULL_TREE, except_stack->data.except_stmt.after_label,
2151: NULL_RTX);
2152: return 1;
2153: }
2154:
2155: /* Generate RTL for the start of an if-then. COND is the expression
2156: whose truth should be tested.
2157:
2158: If EXITFLAG is nonzero, this conditional is visible to
2159: `exit_something'. */
2160:
2161: void
2162: expand_start_cond (cond, exitflag)
2163: tree cond;
2164: int exitflag;
2165: {
2166: struct nesting *thiscond = ALLOC_NESTING ();
2167:
2168: /* Make an entry on cond_stack for the cond we are entering. */
2169:
2170: thiscond->next = cond_stack;
2171: thiscond->all = nesting_stack;
2172: thiscond->depth = ++nesting_depth;
2173: thiscond->data.cond.next_label = gen_label_rtx ();
2174: /* Before we encounter an `else', we don't need a separate exit label
2175: unless there are supposed to be exit statements
2176: to exit this conditional. */
2177: thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2178: thiscond->data.cond.endif_label = thiscond->exit_label;
2179: cond_stack = thiscond;
2180: nesting_stack = thiscond;
2181:
2182: if (output_bytecode)
2183: bc_expand_start_cond (cond, exitflag);
2184: else
2185: do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2186: }
2187:
2188: /* Generate RTL between then-clause and the elseif-clause
2189: of an if-then-elseif-.... */
2190:
2191: void
2192: expand_start_elseif (cond)
2193: tree cond;
2194: {
2195: if (cond_stack->data.cond.endif_label == 0)
2196: cond_stack->data.cond.endif_label = gen_label_rtx ();
2197: emit_jump (cond_stack->data.cond.endif_label);
2198: emit_label (cond_stack->data.cond.next_label);
2199: cond_stack->data.cond.next_label = gen_label_rtx ();
2200: do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2201: }
2202:
2203: /* Generate RTL between the then-clause and the else-clause
2204: of an if-then-else. */
2205:
2206: void
2207: expand_start_else ()
2208: {
2209: if (cond_stack->data.cond.endif_label == 0)
2210: cond_stack->data.cond.endif_label = gen_label_rtx ();
2211:
2212: if (output_bytecode)
2213: {
2214: bc_expand_start_else ();
2215: return;
2216: }
2217:
2218: emit_jump (cond_stack->data.cond.endif_label);
2219: emit_label (cond_stack->data.cond.next_label);
2220: cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2221: }
2222:
2223: /* Generate RTL for the end of an if-then.
2224: Pop the record for it off of cond_stack. */
2225:
2226: void
2227: expand_end_cond ()
2228: {
2229: struct nesting *thiscond = cond_stack;
2230:
2231: if (output_bytecode)
2232: bc_expand_end_cond ();
2233: else
2234: {
2235: do_pending_stack_adjust ();
2236: if (thiscond->data.cond.next_label)
2237: emit_label (thiscond->data.cond.next_label);
2238: if (thiscond->data.cond.endif_label)
2239: emit_label (thiscond->data.cond.endif_label);
2240: }
2241:
2242: POPSTACK (cond_stack);
2243: last_expr_type = 0;
2244: }
2245:
2246:
2247: /* Generate code for the start of an if-then. COND is the expression
2248: whose truth is to be tested; if EXITFLAG is nonzero this conditional
2249: is to be visible to exit_something. It is assumed that the caller
2250: has pushed the previous context on the cond stack. */
2251: void
2252: bc_expand_start_cond (cond, exitflag)
2253: tree cond;
2254: int exitflag;
2255: {
2256: struct nesting *thiscond = cond_stack;
2257:
2258: thiscond->data.case_stmt.nominal_type = cond;
2259: bc_expand_expr (cond);
2260: bc_emit_bytecode (xjumpifnot);
2261: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2262:
2263: #ifdef DEBUG_PRINT_CODE
2264: fputc ('\n', stderr);
2265: #endif
2266: }
2267:
2268: /* Generate the label for the end of an if with
2269: no else- clause. */
2270: void
2271: bc_expand_end_cond ()
2272: {
2273: struct nesting *thiscond = cond_stack;
2274:
2275: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->exit_label));
2276: }
2277:
2278: /* Generate code for the start of the else- clause of
2279: an if-then-else. */
2280: void
2281: bc_expand_start_else ()
2282: {
2283: struct nesting *thiscond = cond_stack;
2284:
2285: thiscond->data.cond.endif_label = thiscond->exit_label;
2286: thiscond->exit_label = gen_label_rtx ();
2287: bc_emit_bytecode (jump);
2288: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2289:
2290: #ifdef DEBUG_PRINT_CODE
2291: fputc ('\n', stderr);
2292: #endif
2293:
2294: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->data.cond.endif_label));
2295: }
2296:
2297: /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2298: loop should be exited by `exit_something'. This is a loop for which
2299: `expand_continue' will jump to the top of the loop.
2300:
2301: Make an entry on loop_stack to record the labels associated with
2302: this loop. */
2303:
2304: struct nesting *
2305: expand_start_loop (exit_flag)
2306: int exit_flag;
2307: {
2308: register struct nesting *thisloop = ALLOC_NESTING ();
2309:
2310: /* Make an entry on loop_stack for the loop we are entering. */
2311:
2312: thisloop->next = loop_stack;
2313: thisloop->all = nesting_stack;
2314: thisloop->depth = ++nesting_depth;
2315: thisloop->data.loop.start_label = gen_label_rtx ();
2316: thisloop->data.loop.end_label = gen_label_rtx ();
2317: thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2318: thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2319: loop_stack = thisloop;
2320: nesting_stack = thisloop;
2321:
2322: if (output_bytecode)
2323: {
2324: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2325: return thisloop;
2326: }
2327:
2328: do_pending_stack_adjust ();
2329: emit_queue ();
2330: emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2331: emit_label (thisloop->data.loop.start_label);
2332:
2333: return thisloop;
2334: }
2335:
2336: /* Like expand_start_loop but for a loop where the continuation point
2337: (for expand_continue_loop) will be specified explicitly. */
2338:
2339: struct nesting *
2340: expand_start_loop_continue_elsewhere (exit_flag)
2341: int exit_flag;
2342: {
2343: struct nesting *thisloop = expand_start_loop (exit_flag);
2344: loop_stack->data.loop.continue_label = gen_label_rtx ();
2345: return thisloop;
2346: }
2347:
2348: /* Specify the continuation point for a loop started with
2349: expand_start_loop_continue_elsewhere.
2350: Use this at the point in the code to which a continue statement
2351: should jump. */
2352:
2353: void
2354: expand_loop_continue_here ()
2355: {
2356: if (output_bytecode)
2357: {
2358: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (loop_stack->data.loop.continue_label));
2359: return;
2360: }
2361: do_pending_stack_adjust ();
2362: emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2363: emit_label (loop_stack->data.loop.continue_label);
2364: }
2365:
2366: /* End a loop. */
2367: static void
2368: bc_expand_end_loop ()
2369: {
2370: struct nesting *thisloop = loop_stack;
2371:
2372: bc_emit_bytecode (jump);
2373: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2374:
2375: #ifdef DEBUG_PRINT_CODE
2376: fputc ('\n', stderr);
2377: #endif
2378:
2379: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->exit_label));
2380: POPSTACK (loop_stack);
2381: last_expr_type = 0;
2382: }
2383:
2384:
2385: /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2386: Pop the block off of loop_stack. */
2387:
2388: void
2389: expand_end_loop ()
2390: {
2391: register rtx insn;
2392: register rtx start_label;
2393: rtx last_test_insn = 0;
2394: int num_insns = 0;
2395:
2396: if (output_bytecode)
2397: {
2398: bc_expand_end_loop ();
2399: return;
2400: }
2401:
2402: insn = get_last_insn ();
2403: start_label = loop_stack->data.loop.start_label;
2404:
2405: /* Mark the continue-point at the top of the loop if none elsewhere. */
2406: if (start_label == loop_stack->data.loop.continue_label)
2407: emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2408:
2409: do_pending_stack_adjust ();
2410:
2411: /* If optimizing, perhaps reorder the loop. If the loop
2412: starts with a conditional exit, roll that to the end
2413: where it will optimize together with the jump back.
2414:
2415: We look for the last conditional branch to the exit that we encounter
2416: before hitting 30 insns or a CALL_INSN. If we see an unconditional
2417: branch to the exit first, use it.
2418:
2419: We must also stop at NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes
2420: because moving them is not valid. */
2421:
2422: if (optimize
2423: &&
2424: ! (GET_CODE (insn) == JUMP_INSN
2425: && GET_CODE (PATTERN (insn)) == SET
2426: && SET_DEST (PATTERN (insn)) == pc_rtx
2427: && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2428: {
2429: /* Scan insns from the top of the loop looking for a qualified
2430: conditional exit. */
2431: for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2432: insn = NEXT_INSN (insn))
2433: {
2434: if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == CODE_LABEL)
2435: break;
2436:
2437: if (GET_CODE (insn) == NOTE
2438: && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2439: || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2440: break;
2441:
2442: if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2443: num_insns++;
2444:
2445: if (last_test_insn && num_insns > 30)
2446: break;
2447:
2448: if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
2449: && SET_DEST (PATTERN (insn)) == pc_rtx
2450: && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
2451: && ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
2452: && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2453: == loop_stack->data.loop.end_label))
2454: || (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
2455: && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2456: == loop_stack->data.loop.end_label))))
2457: last_test_insn = insn;
2458:
2459: if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
2460: && GET_CODE (PATTERN (insn)) == SET
2461: && SET_DEST (PATTERN (insn)) == pc_rtx
2462: && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF
2463: && (XEXP (SET_SRC (PATTERN (insn)), 0)
2464: == loop_stack->data.loop.end_label))
2465: /* Include BARRIER. */
2466: last_test_insn = NEXT_INSN (insn);
2467: }
2468:
2469: if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2470: {
2471: /* We found one. Move everything from there up
2472: to the end of the loop, and add a jump into the loop
2473: to jump to there. */
2474: register rtx newstart_label = gen_label_rtx ();
2475: register rtx start_move = start_label;
2476:
2477: /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2478: then we want to move this note also. */
2479: if (GET_CODE (PREV_INSN (start_move)) == NOTE
2480: && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2481: == NOTE_INSN_LOOP_CONT))
2482: start_move = PREV_INSN (start_move);
2483:
2484: emit_label_after (newstart_label, PREV_INSN (start_move));
2485: reorder_insns (start_move, last_test_insn, get_last_insn ());
2486: emit_jump_insn_after (gen_jump (start_label),
2487: PREV_INSN (newstart_label));
2488: emit_barrier_after (PREV_INSN (newstart_label));
2489: start_label = newstart_label;
2490: }
2491: }
2492:
2493: emit_jump (start_label);
2494: emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2495: emit_label (loop_stack->data.loop.end_label);
2496:
2497: POPSTACK (loop_stack);
2498:
2499: last_expr_type = 0;
2500: }
2501:
2502: /* Generate a jump to the current loop's continue-point.
2503: This is usually the top of the loop, but may be specified
2504: explicitly elsewhere. If not currently inside a loop,
2505: return 0 and do nothing; caller will print an error message. */
2506:
2507: int
2508: expand_continue_loop (whichloop)
2509: struct nesting *whichloop;
2510: {
2511: last_expr_type = 0;
2512: if (whichloop == 0)
2513: whichloop = loop_stack;
2514: if (whichloop == 0)
2515: return 0;
2516: expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2517: NULL_RTX);
2518: return 1;
2519: }
2520:
2521: /* Generate a jump to exit the current loop. If not currently inside a loop,
2522: return 0 and do nothing; caller will print an error message. */
2523:
2524: int
2525: expand_exit_loop (whichloop)
2526: struct nesting *whichloop;
2527: {
2528: last_expr_type = 0;
2529: if (whichloop == 0)
2530: whichloop = loop_stack;
2531: if (whichloop == 0)
2532: return 0;
2533: expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2534: return 1;
2535: }
2536:
2537: /* Generate a conditional jump to exit the current loop if COND
2538: evaluates to zero. If not currently inside a loop,
2539: return 0 and do nothing; caller will print an error message. */
2540:
2541: int
2542: expand_exit_loop_if_false (whichloop, cond)
2543: struct nesting *whichloop;
2544: tree cond;
2545: {
2546: last_expr_type = 0;
2547: if (whichloop == 0)
2548: whichloop = loop_stack;
2549: if (whichloop == 0)
2550: return 0;
2551: if (output_bytecode)
2552: {
2553: bc_expand_expr (cond);
2554: bc_expand_goto_internal (xjumpifnot,
2555: BYTECODE_BC_LABEL (whichloop->exit_label),
2556: NULL_RTX);
2557: }
2558: else
2559: do_jump (cond, whichloop->data.loop.end_label, NULL_RTX);
2560:
2561: return 1;
2562: }
2563:
2564: /* Return non-zero if we should preserve sub-expressions as separate
2565: pseudos. We never do so if we aren't optimizing. We always do so
2566: if -fexpensive-optimizations.
2567:
2568: Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2569: the loop may still be a small one. */
2570:
2571: int
2572: preserve_subexpressions_p ()
2573: {
2574: rtx insn;
2575:
2576: if (flag_expensive_optimizations)
2577: return 1;
2578:
2579: if (optimize == 0 || loop_stack == 0)
2580: return 0;
2581:
2582: insn = get_last_insn_anywhere ();
2583:
2584: return (insn
2585: && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2586: < n_non_fixed_regs * 3));
2587:
2588: }
2589:
2590: /* Generate a jump to exit the current loop, conditional, binding contour
2591: or case statement. Not all such constructs are visible to this function,
2592: only those started with EXIT_FLAG nonzero. Individual languages use
2593: the EXIT_FLAG parameter to control which kinds of constructs you can
2594: exit this way.
2595:
2596: If not currently inside anything that can be exited,
2597: return 0 and do nothing; caller will print an error message. */
2598:
2599: int
2600: expand_exit_something ()
2601: {
2602: struct nesting *n;
2603: last_expr_type = 0;
2604: for (n = nesting_stack; n; n = n->all)
2605: if (n->exit_label != 0)
2606: {
2607: expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2608: return 1;
2609: }
2610:
2611: return 0;
2612: }
2613:
2614: /* Generate RTL to return from the current function, with no value.
2615: (That is, we do not do anything about returning any value.) */
2616:
2617: void
2618: expand_null_return ()
2619: {
2620: struct nesting *block = block_stack;
2621: rtx last_insn = 0;
2622:
2623: if (output_bytecode)
2624: {
2625: bc_emit_instruction (ret);
2626: return;
2627: }
2628:
2629: /* Does any pending block have cleanups? */
2630:
2631: while (block && block->data.block.cleanups == 0)
2632: block = block->next;
2633:
2634: /* If yes, use a goto to return, since that runs cleanups. */
2635:
2636: expand_null_return_1 (last_insn, block != 0);
2637: }
2638:
2639: /* Generate RTL to return from the current function, with value VAL. */
2640:
2641: void
2642: expand_value_return (val)
2643: rtx val;
2644: {
2645: struct nesting *block = block_stack;
2646: rtx last_insn = get_last_insn ();
2647: rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2648:
2649: /* Copy the value to the return location
2650: unless it's already there. */
2651:
2652: if (return_reg != val)
2653: {
2654: #ifdef PROMOTE_FUNCTION_RETURN
2655: enum machine_mode mode = DECL_MODE (DECL_RESULT (current_function_decl));
2656: tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2657: int unsignedp = TREE_UNSIGNED (type);
2658:
2659: if (TREE_CODE (type) == INTEGER_TYPE || TREE_CODE (type) == ENUMERAL_TYPE
2660: || TREE_CODE (type) == BOOLEAN_TYPE || TREE_CODE (type) == CHAR_TYPE
2661: || TREE_CODE (type) == REAL_TYPE || TREE_CODE (type) == POINTER_TYPE
2662: || TREE_CODE (type) == OFFSET_TYPE)
2663: {
2664: PROMOTE_MODE (mode, unsignedp, type);
2665: }
2666:
2667: if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2668: convert_move (return_reg, val, unsignedp);
2669: else
2670: #endif
2671: emit_move_insn (return_reg, val);
2672: }
2673: if (GET_CODE (return_reg) == REG
2674: && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2675: emit_insn (gen_rtx (USE, VOIDmode, return_reg));
2676:
2677: /* Does any pending block have cleanups? */
2678:
2679: while (block && block->data.block.cleanups == 0)
2680: block = block->next;
2681:
2682: /* If yes, use a goto to return, since that runs cleanups.
2683: Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2684:
2685: expand_null_return_1 (last_insn, block != 0);
2686: }
2687:
2688: /* Output a return with no value. If LAST_INSN is nonzero,
2689: pretend that the return takes place after LAST_INSN.
2690: If USE_GOTO is nonzero then don't use a return instruction;
2691: go to the return label instead. This causes any cleanups
2692: of pending blocks to be executed normally. */
2693:
2694: static void
2695: expand_null_return_1 (last_insn, use_goto)
2696: rtx last_insn;
2697: int use_goto;
2698: {
2699: rtx end_label = cleanup_label ? cleanup_label : return_label;
2700:
2701: clear_pending_stack_adjust ();
2702: do_pending_stack_adjust ();
2703: last_expr_type = 0;
2704:
2705: /* PCC-struct return always uses an epilogue. */
2706: if (current_function_returns_pcc_struct || use_goto)
2707: {
2708: if (end_label == 0)
2709: end_label = return_label = gen_label_rtx ();
2710: expand_goto_internal (NULL_TREE, end_label, last_insn);
2711: return;
2712: }
2713:
2714: /* Otherwise output a simple return-insn if one is available,
2715: unless it won't do the job. */
2716: #ifdef HAVE_return
2717: if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2718: {
2719: emit_jump_insn (gen_return ());
2720: emit_barrier ();
2721: return;
2722: }
2723: #endif
2724:
2725: /* Otherwise jump to the epilogue. */
2726: expand_goto_internal (NULL_TREE, end_label, last_insn);
2727: }
2728:
2729: /* Generate RTL to evaluate the expression RETVAL and return it
2730: from the current function. */
2731:
2732: void
2733: expand_return (retval)
2734: tree retval;
2735: {
2736: /* If there are any cleanups to be performed, then they will
2737: be inserted following LAST_INSN. It is desirable
2738: that the last_insn, for such purposes, should be the
2739: last insn before computing the return value. Otherwise, cleanups
2740: which call functions can clobber the return value. */
2741: /* ??? rms: I think that is erroneous, because in C++ it would
2742: run destructors on variables that might be used in the subsequent
2743: computation of the return value. */
2744: rtx last_insn = 0;
2745: register rtx val = 0;
2746: register rtx op0;
2747: tree retval_rhs;
2748: int cleanups;
2749: struct nesting *block;
2750:
2751: /* Bytecode returns are quite simple, just leave the result on the
2752: arithmetic stack. */
2753: if (output_bytecode)
2754: {
2755: bc_expand_expr (retval);
2756: bc_emit_instruction (ret);
2757: return;
2758: }
2759:
2760: /* If function wants no value, give it none. */
2761: if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2762: {
2763: expand_expr (retval, NULL_RTX, VOIDmode, 0);
2764: emit_queue ();
2765: expand_null_return ();
2766: return;
2767: }
2768:
2769: /* Are any cleanups needed? E.g. C++ destructors to be run? */
2770: cleanups = any_pending_cleanups (1);
2771:
2772: if (TREE_CODE (retval) == RESULT_DECL)
2773: retval_rhs = retval;
2774: else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2775: && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2776: retval_rhs = TREE_OPERAND (retval, 1);
2777: else if (TREE_TYPE (retval) == void_type_node)
2778: /* Recognize tail-recursive call to void function. */
2779: retval_rhs = retval;
2780: else
2781: retval_rhs = NULL_TREE;
2782:
2783: /* Only use `last_insn' if there are cleanups which must be run. */
2784: if (cleanups || cleanup_label != 0)
2785: last_insn = get_last_insn ();
2786:
2787: /* Distribute return down conditional expr if either of the sides
2788: may involve tail recursion (see test below). This enhances the number
2789: of tail recursions we see. Don't do this always since it can produce
2790: sub-optimal code in some cases and we distribute assignments into
2791: conditional expressions when it would help. */
2792:
2793: if (optimize && retval_rhs != 0
2794: && frame_offset == 0
2795: && TREE_CODE (retval_rhs) == COND_EXPR
2796: && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2797: || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2798: {
2799: rtx label = gen_label_rtx ();
2800: tree expr;
2801:
2802: do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2803: expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2804: DECL_RESULT (current_function_decl),
2805: TREE_OPERAND (retval_rhs, 1));
2806: TREE_SIDE_EFFECTS (expr) = 1;
2807: expand_return (expr);
2808: emit_label (label);
2809:
2810: expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2811: DECL_RESULT (current_function_decl),
2812: TREE_OPERAND (retval_rhs, 2));
2813: TREE_SIDE_EFFECTS (expr) = 1;
2814: expand_return (expr);
2815: return;
2816: }
2817:
2818: /* For tail-recursive call to current function,
2819: just jump back to the beginning.
2820: It's unsafe if any auto variable in this function
2821: has its address taken; for simplicity,
2822: require stack frame to be empty. */
2823: if (optimize && retval_rhs != 0
2824: && frame_offset == 0
2825: && TREE_CODE (retval_rhs) == CALL_EXPR
2826: && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
2827: && TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == current_function_decl
2828: /* Finish checking validity, and if valid emit code
2829: to set the argument variables for the new call. */
2830: && tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
2831: DECL_ARGUMENTS (current_function_decl)))
2832: {
2833: if (tail_recursion_label == 0)
2834: {
2835: tail_recursion_label = gen_label_rtx ();
2836: emit_label_after (tail_recursion_label,
2837: tail_recursion_reentry);
2838: }
2839: emit_queue ();
2840: expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2841: emit_barrier ();
2842: return;
2843: }
2844: #ifdef HAVE_return
2845: /* This optimization is safe if there are local cleanups
2846: because expand_null_return takes care of them.
2847: ??? I think it should also be safe when there is a cleanup label,
2848: because expand_null_return takes care of them, too.
2849: Any reason why not? */
2850: if (HAVE_return && cleanup_label == 0
2851: && ! current_function_returns_pcc_struct
2852: && BRANCH_COST <= 1)
2853: {
2854: /* If this is return x == y; then generate
2855: if (x == y) return 1; else return 0;
2856: if we can do it with explicit return insns and
2857: branches are cheap. */
2858: if (retval_rhs)
2859: switch (TREE_CODE (retval_rhs))
2860: {
2861: case EQ_EXPR:
2862: case NE_EXPR:
2863: case GT_EXPR:
2864: case GE_EXPR:
2865: case LT_EXPR:
2866: case LE_EXPR:
2867: case TRUTH_ANDIF_EXPR:
2868: case TRUTH_ORIF_EXPR:
2869: case TRUTH_AND_EXPR:
2870: case TRUTH_OR_EXPR:
2871: case TRUTH_NOT_EXPR:
2872: case TRUTH_XOR_EXPR:
2873: op0 = gen_label_rtx ();
2874: jumpifnot (retval_rhs, op0);
2875: expand_value_return (const1_rtx);
2876: emit_label (op0);
2877: expand_value_return (const0_rtx);
2878: return;
2879: }
2880: }
2881: #endif /* HAVE_return */
2882:
2883: if (cleanups
2884: && retval_rhs != 0
2885: && TREE_TYPE (retval_rhs) != void_type_node
2886: && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2887: {
2888: /* Calculate the return value into a pseudo reg. */
2889: val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2890: emit_queue ();
2891: /* All temporaries have now been used. */
2892: free_temp_slots ();
2893: /* Return the calculated value, doing cleanups first. */
2894: expand_value_return (val);
2895: }
2896: else
2897: {
2898: /* No cleanups or no hard reg used;
2899: calculate value into hard return reg. */
2900: expand_expr (retval, const0_rtx, VOIDmode, 0);
2901: emit_queue ();
2902: free_temp_slots ();
2903: expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2904: }
2905: }
2906:
2907: /* Return 1 if the end of the generated RTX is not a barrier.
2908: This means code already compiled can drop through. */
2909:
2910: int
2911: drop_through_at_end_p ()
2912: {
2913: rtx insn = get_last_insn ();
2914: while (insn && GET_CODE (insn) == NOTE)
2915: insn = PREV_INSN (insn);
2916: return insn && GET_CODE (insn) != BARRIER;
2917: }
2918:
2919: /* Emit code to alter this function's formal parms for a tail-recursive call.
2920: ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2921: FORMALS is the chain of decls of formals.
2922: Return 1 if this can be done;
2923: otherwise return 0 and do not emit any code. */
2924:
2925: static int
2926: tail_recursion_args (actuals, formals)
2927: tree actuals, formals;
2928: {
2929: register tree a = actuals, f = formals;
2930: register int i;
2931: register rtx *argvec;
2932:
2933: /* Check that number and types of actuals are compatible
2934: with the formals. This is not always true in valid C code.
2935: Also check that no formal needs to be addressable
2936: and that all formals are scalars. */
2937:
2938: /* Also count the args. */
2939:
2940: for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2941: {
2942: if (TREE_TYPE (TREE_VALUE (a)) != TREE_TYPE (f))
2943: return 0;
2944: if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
2945: return 0;
2946: }
2947: if (a != 0 || f != 0)
2948: return 0;
2949:
2950: /* Compute all the actuals. */
2951:
2952: argvec = (rtx *) alloca (i * sizeof (rtx));
2953:
2954: for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2955: argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
2956:
2957: /* Find which actual values refer to current values of previous formals.
2958: Copy each of them now, before any formal is changed. */
2959:
2960: for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2961: {
2962: int copy = 0;
2963: register int j;
2964: for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
2965: if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
2966: { copy = 1; break; }
2967: if (copy)
2968: argvec[i] = copy_to_reg (argvec[i]);
2969: }
2970:
2971: /* Store the values of the actuals into the formals. */
2972:
2973: for (f = formals, a = actuals, i = 0; f;
2974: f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
2975: {
2976: if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
2977: emit_move_insn (DECL_RTL (f), argvec[i]);
2978: else
2979: convert_move (DECL_RTL (f), argvec[i],
2980: TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
2981: }
2982:
2983: free_temp_slots ();
2984: return 1;
2985: }
2986:
2987: /* Generate the RTL code for entering a binding contour.
2988: The variables are declared one by one, by calls to `expand_decl'.
2989:
2990: EXIT_FLAG is nonzero if this construct should be visible to
2991: `exit_something'. */
2992:
2993: void
2994: expand_start_bindings (exit_flag)
2995: int exit_flag;
2996: {
2997: struct nesting *thisblock = ALLOC_NESTING ();
2998: rtx note;
2999:
3000: if (!output_bytecode)
3001: note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
3002:
3003: /* Make an entry on block_stack for the block we are entering. */
3004:
3005: thisblock->next = block_stack;
3006: thisblock->all = nesting_stack;
3007: thisblock->depth = ++nesting_depth;
3008: thisblock->data.block.stack_level = 0;
3009: thisblock->data.block.cleanups = 0;
3010: thisblock->data.block.function_call_count = 0;
3011: #if 0
3012: if (block_stack)
3013: {
3014: if (block_stack->data.block.cleanups == NULL_TREE
3015: && (block_stack->data.block.outer_cleanups == NULL_TREE
3016: || block_stack->data.block.outer_cleanups == empty_cleanup_list))
3017: thisblock->data.block.outer_cleanups = empty_cleanup_list;
3018: else
3019: thisblock->data.block.outer_cleanups
3020: = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3021: block_stack->data.block.outer_cleanups);
3022: }
3023: else
3024: thisblock->data.block.outer_cleanups = 0;
3025: #endif
3026: #if 1
3027: if (block_stack
3028: && !(block_stack->data.block.cleanups == NULL_TREE
3029: && block_stack->data.block.outer_cleanups == NULL_TREE))
3030: thisblock->data.block.outer_cleanups
3031: = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3032: block_stack->data.block.outer_cleanups);
3033: else
3034: thisblock->data.block.outer_cleanups = 0;
3035: #endif
3036: thisblock->data.block.label_chain = 0;
3037: thisblock->data.block.innermost_stack_block = stack_block_stack;
3038: thisblock->data.block.first_insn = note;
3039: thisblock->data.block.block_start_count = ++block_start_count;
3040: thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3041: block_stack = thisblock;
3042: nesting_stack = thisblock;
3043:
3044: if (!output_bytecode)
3045: {
3046: /* Make a new level for allocating stack slots. */
3047: push_temp_slots ();
3048: }
3049: }
3050:
3051: /* Given a pointer to a BLOCK node, save a pointer to the most recently
3052: generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
3053: BLOCK node. */
3054:
3055: void
3056: remember_end_note (block)
3057: register tree block;
3058: {
3059: BLOCK_END_NOTE (block) = last_block_end_note;
3060: last_block_end_note = NULL_RTX;
3061: }
3062:
3063: /* Generate RTL code to terminate a binding contour.
3064: VARS is the chain of VAR_DECL nodes
3065: for the variables bound in this contour.
3066: MARK_ENDS is nonzero if we should put a note at the beginning
3067: and end of this binding contour.
3068:
3069: DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3070: (That is true automatically if the contour has a saved stack level.) */
3071:
3072: void
3073: expand_end_bindings (vars, mark_ends, dont_jump_in)
3074: tree vars;
3075: int mark_ends;
3076: int dont_jump_in;
3077: {
3078: register struct nesting *thisblock = block_stack;
3079: register tree decl;
3080:
3081: if (output_bytecode)
3082: {
3083: bc_expand_end_bindings (vars, mark_ends, dont_jump_in);
3084: return;
3085: }
3086:
3087: if (warn_unused)
3088: for (decl = vars; decl; decl = TREE_CHAIN (decl))
3089: if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
3090: && ! DECL_IN_SYSTEM_HEADER (decl))
3091: warning_with_decl (decl, "unused variable `%s'");
3092:
3093: if (thisblock->exit_label)
3094: {
3095: do_pending_stack_adjust ();
3096: emit_label (thisblock->exit_label);
3097: }
3098:
3099: /* If necessary, make a handler for nonlocal gotos taking
3100: place in the function calls in this block. */
3101: if (function_call_count != thisblock->data.block.function_call_count
3102: && nonlocal_labels
3103: /* Make handler for outermost block
3104: if there were any nonlocal gotos to this function. */
3105: && (thisblock->next == 0 ? current_function_has_nonlocal_label
3106: /* Make handler for inner block if it has something
3107: special to do when you jump out of it. */
3108: : (thisblock->data.block.cleanups != 0
3109: || thisblock->data.block.stack_level != 0)))
3110: {
3111: tree link;
3112: rtx afterward = gen_label_rtx ();
3113: rtx handler_label = gen_label_rtx ();
3114: rtx save_receiver = gen_reg_rtx (Pmode);
3115: rtx insns;
3116:
3117: /* Don't let jump_optimize delete the handler. */
3118: LABEL_PRESERVE_P (handler_label) = 1;
3119:
3120: /* Record the handler address in the stack slot for that purpose,
3121: during this block, saving and restoring the outer value. */
3122: if (thisblock->next != 0)
3123: {
3124: emit_move_insn (nonlocal_goto_handler_slot, save_receiver);
3125:
3126: start_sequence ();
3127: emit_move_insn (save_receiver, nonlocal_goto_handler_slot);
3128: insns = get_insns ();
3129: end_sequence ();
3130: emit_insns_before (insns, thisblock->data.block.first_insn);
3131: }
3132:
3133: start_sequence ();
3134: emit_move_insn (nonlocal_goto_handler_slot,
3135: gen_rtx (LABEL_REF, Pmode, handler_label));
3136: insns = get_insns ();
3137: end_sequence ();
3138: emit_insns_before (insns, thisblock->data.block.first_insn);
3139:
3140: /* Jump around the handler; it runs only when specially invoked. */
3141: emit_jump (afterward);
3142: emit_label (handler_label);
3143:
3144: #ifdef HAVE_nonlocal_goto
3145: if (! HAVE_nonlocal_goto)
3146: #endif
3147: /* First adjust our frame pointer to its actual value. It was
3148: previously set to the start of the virtual area corresponding to
3149: the stacked variables when we branched here and now needs to be
3150: adjusted to the actual hardware fp value.
3151:
3152: Assignments are to virtual registers are converted by
3153: instantiate_virtual_regs into the corresponding assignment
3154: to the underlying register (fp in this case) that makes
3155: the original assignment true.
3156: So the following insn will actually be
3157: decrementing fp by STARTING_FRAME_OFFSET. */
3158: emit_move_insn (virtual_stack_vars_rtx, frame_pointer_rtx);
3159:
3160: #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3161: if (fixed_regs[ARG_POINTER_REGNUM])
3162: {
3163: #ifdef ELIMINABLE_REGS
3164: /* If the argument pointer can be eliminated in favor of the
3165: frame pointer, we don't need to restore it. We assume here
3166: that if such an elimination is present, it can always be used.
3167: This is the case on all known machines; if we don't make this
3168: assumption, we do unnecessary saving on many machines. */
3169: static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3170: int i;
3171:
3172: for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3173: if (elim_regs[i].from == ARG_POINTER_REGNUM
3174: && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3175: break;
3176:
3177: if (i == sizeof elim_regs / sizeof elim_regs [0])
3178: #endif
3179: {
3180: /* Now restore our arg pointer from the address at which it
3181: was saved in our stack frame.
3182: If there hasn't be space allocated for it yet, make
3183: some now. */
3184: if (arg_pointer_save_area == 0)
3185: arg_pointer_save_area
3186: = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3187: emit_move_insn (virtual_incoming_args_rtx,
3188: /* We need a pseudo here, or else
3189: instantiate_virtual_regs_1 complains. */
3190: copy_to_reg (arg_pointer_save_area));
3191: }
3192: }
3193: #endif
3194:
3195: /* The handler expects the desired label address in the static chain
3196: register. It tests the address and does an appropriate jump
3197: to whatever label is desired. */
3198: for (link = nonlocal_labels; link; link = TREE_CHAIN (link))
3199: /* Skip any labels we shouldn't be able to jump to from here. */
3200: if (! DECL_TOO_LATE (TREE_VALUE (link)))
3201: {
3202: rtx not_this = gen_label_rtx ();
3203: rtx this = gen_label_rtx ();
3204: do_jump_if_equal (static_chain_rtx,
3205: gen_rtx (LABEL_REF, Pmode, DECL_RTL (TREE_VALUE (link))),
3206: this, 0);
3207: emit_jump (not_this);
3208: emit_label (this);
3209: expand_goto (TREE_VALUE (link));
3210: emit_label (not_this);
3211: }
3212: /* If label is not recognized, abort. */
3213: emit_library_call (gen_rtx (SYMBOL_REF, Pmode, "abort"), 0,
3214: VOIDmode, 0);
3215: emit_label (afterward);
3216: }
3217:
3218: /* Don't allow jumping into a block that has cleanups or a stack level. */
3219: if (dont_jump_in
3220: || thisblock->data.block.stack_level != 0
3221: || thisblock->data.block.cleanups != 0)
3222: {
3223: struct label_chain *chain;
3224:
3225: /* Any labels in this block are no longer valid to go to.
3226: Mark them to cause an error message. */
3227: for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3228: {
3229: DECL_TOO_LATE (chain->label) = 1;
3230: /* If any goto without a fixup came to this label,
3231: that must be an error, because gotos without fixups
3232: come from outside all saved stack-levels and all cleanups. */
3233: if (TREE_ADDRESSABLE (chain->label))
3234: error_with_decl (chain->label,
3235: "label `%s' used before containing binding contour");
3236: }
3237: }
3238:
3239: /* Restore stack level in effect before the block
3240: (only if variable-size objects allocated). */
3241: /* Perform any cleanups associated with the block. */
3242:
3243: if (thisblock->data.block.stack_level != 0
3244: || thisblock->data.block.cleanups != 0)
3245: {
3246: /* Don't let cleanups affect ({...}) constructs. */
3247: int old_expr_stmts_for_value = expr_stmts_for_value;
3248: rtx old_last_expr_value = last_expr_value;
3249: tree old_last_expr_type = last_expr_type;
3250: expr_stmts_for_value = 0;
3251:
3252: /* Do the cleanups. */
3253: expand_cleanups (thisblock->data.block.cleanups, NULL_TREE);
3254: do_pending_stack_adjust ();
3255:
3256: expr_stmts_for_value = old_expr_stmts_for_value;
3257: last_expr_value = old_last_expr_value;
3258: last_expr_type = old_last_expr_type;
3259:
3260: /* Restore the stack level. */
3261:
3262: if (thisblock->data.block.stack_level != 0)
3263: {
3264: emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3265: thisblock->data.block.stack_level, NULL_RTX);
3266: if (nonlocal_goto_handler_slot != 0)
3267: emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3268: NULL_RTX);
3269: }
3270:
3271: /* Any gotos out of this block must also do these things.
3272: Also report any gotos with fixups that came to labels in this
3273: level. */
3274: fixup_gotos (thisblock,
3275: thisblock->data.block.stack_level,
3276: thisblock->data.block.cleanups,
3277: thisblock->data.block.first_insn,
3278: dont_jump_in);
3279: }
3280:
3281: /* Mark the beginning and end of the scope if requested.
3282: We do this now, after running cleanups on the variables
3283: just going out of scope, so they are in scope for their cleanups. */
3284:
3285: if (mark_ends)
3286: last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3287: else
3288: /* Get rid of the beginning-mark if we don't make an end-mark. */
3289: NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3290:
3291: /* If doing stupid register allocation, make sure lives of all
3292: register variables declared here extend thru end of scope. */
3293:
3294: if (obey_regdecls)
3295: for (decl = vars; decl; decl = TREE_CHAIN (decl))
3296: {
3297: rtx rtl = DECL_RTL (decl);
3298: if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
3299: use_variable (rtl);
3300: }
3301:
3302: /* Restore block_stack level for containing block. */
3303:
3304: stack_block_stack = thisblock->data.block.innermost_stack_block;
3305: POPSTACK (block_stack);
3306:
3307: /* Pop the stack slot nesting and free any slots at this level. */
3308: pop_temp_slots ();
3309: }
3310:
3311:
3312: /* End a binding contour.
3313: VARS is the chain of VAR_DECL nodes for the variables bound
3314: in this contour. MARK_ENDS is nonzer if we should put a note
3315: at the beginning and end of this binding contour.
3316: DONT_JUMP_IN is nonzero if it is not valid to jump into this
3317: contour. */
3318:
3319: void
3320: bc_expand_end_bindings (vars, mark_ends, dont_jump_in)
3321: tree vars;
3322: int mark_ends;
3323: int dont_jump_in;
3324: {
3325: struct nesting *thisbind = nesting_stack;
3326: tree decl;
3327:
3328: if (warn_unused)
3329: for (decl = vars; decl; decl = TREE_CHAIN (decl))
3330: if (! TREE_USED (TREE_VALUE (decl)) && TREE_CODE (TREE_VALUE (decl)) == VAR_DECL)
3331: warning_with_decl (decl, "unused variable `%s'");
3332:
3333: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisbind->exit_label));
3334:
3335: /* Pop block/bindings off stack */
3336: POPSTACK (nesting_stack);
3337: POPSTACK (block_stack);
3338: }
3339:
3340: /* Generate RTL for the automatic variable declaration DECL.
3341: (Other kinds of declarations are simply ignored if seen here.)
3342: CLEANUP is an expression to be executed at exit from this binding contour;
3343: for example, in C++, it might call the destructor for this variable.
3344:
3345: If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3346: either before or after calling `expand_decl' but before compiling
3347: any subsequent expressions. This is because CLEANUP may be expanded
3348: more than once, on different branches of execution.
3349: For the same reason, CLEANUP may not contain a CALL_EXPR
3350: except as its topmost node--else `preexpand_calls' would get confused.
3351:
3352: If CLEANUP is nonzero and DECL is zero, we record a cleanup
3353: that is not associated with any particular variable.
3354:
3355: There is no special support here for C++ constructors.
3356: They should be handled by the proper code in DECL_INITIAL. */
3357:
3358: void
3359: expand_decl (decl)
3360: register tree decl;
3361: {
3362: struct nesting *thisblock = block_stack;
3363: tree type;
3364:
3365: if (output_bytecode)
3366: {
3367: bc_expand_decl (decl, 0);
3368: return;
3369: }
3370:
3371: type = TREE_TYPE (decl);
3372:
3373: /* Only automatic variables need any expansion done.
3374: Static and external variables, and external functions,
3375: will be handled by `assemble_variable' (called from finish_decl).
3376: TYPE_DECL and CONST_DECL require nothing.
3377: PARM_DECLs are handled in `assign_parms'. */
3378:
3379: if (TREE_CODE (decl) != VAR_DECL)
3380: return;
3381: if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3382: return;
3383:
3384: /* Create the RTL representation for the variable. */
3385:
3386: if (type == error_mark_node)
3387: DECL_RTL (decl) = gen_rtx (MEM, BLKmode, const0_rtx);
3388: else if (DECL_SIZE (decl) == 0)
3389: /* Variable with incomplete type. */
3390: {
3391: if (DECL_INITIAL (decl) == 0)
3392: /* Error message was already done; now avoid a crash. */
3393: DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3394: else
3395: /* An initializer is going to decide the size of this array.
3396: Until we know the size, represent its address with a reg. */
3397: DECL_RTL (decl) = gen_rtx (MEM, BLKmode, gen_reg_rtx (Pmode));
3398: }
3399: else if (DECL_MODE (decl) != BLKmode
3400: /* If -ffloat-store, don't put explicit float vars
3401: into regs. */
3402: && !(flag_float_store
3403: && TREE_CODE (type) == REAL_TYPE)
3404: && ! TREE_THIS_VOLATILE (decl)
3405: && ! TREE_ADDRESSABLE (decl)
3406: && (DECL_REGISTER (decl) || ! obey_regdecls))
3407: {
3408: /* Automatic variable that can go in a register. */
3409: enum machine_mode reg_mode = DECL_MODE (decl);
3410: int unsignedp = TREE_UNSIGNED (type);
3411:
3412: if (TREE_CODE (type) == INTEGER_TYPE || TREE_CODE (type) == ENUMERAL_TYPE
3413: || TREE_CODE (type) == BOOLEAN_TYPE || TREE_CODE (type) == CHAR_TYPE
3414: || TREE_CODE (type) == REAL_TYPE || TREE_CODE (type) == POINTER_TYPE
3415: || TREE_CODE (type) == OFFSET_TYPE)
3416: {
3417: PROMOTE_MODE (reg_mode, unsignedp, type);
3418: }
3419:
3420: if (TREE_CODE (type) == COMPLEX_TYPE)
3421: {
3422: rtx realpart, imagpart;
3423: enum machine_mode partmode = TYPE_MODE (TREE_TYPE (type));
3424:
3425: /* For a complex type variable, make a CONCAT of two pseudos
3426: so that the real and imaginary parts
3427: can be allocated separately. */
3428: realpart = gen_reg_rtx (partmode);
3429: REG_USERVAR_P (realpart) = 1;
3430: imagpart = gen_reg_rtx (partmode);
3431: REG_USERVAR_P (imagpart) = 1;
3432: DECL_RTL (decl) = gen_rtx (CONCAT, reg_mode, realpart, imagpart);
3433: }
3434: else
3435: {
3436: DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3437: if (TREE_CODE (type) == POINTER_TYPE)
3438: mark_reg_pointer (DECL_RTL (decl));
3439: REG_USERVAR_P (DECL_RTL (decl)) = 1;
3440: }
3441: }
3442: else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
3443: {
3444: /* Variable of fixed size that goes on the stack. */
3445: rtx oldaddr = 0;
3446: rtx addr;
3447:
3448: /* If we previously made RTL for this decl, it must be an array
3449: whose size was determined by the initializer.
3450: The old address was a register; set that register now
3451: to the proper address. */
3452: if (DECL_RTL (decl) != 0)
3453: {
3454: if (GET_CODE (DECL_RTL (decl)) != MEM
3455: || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3456: abort ();
3457: oldaddr = XEXP (DECL_RTL (decl), 0);
3458: }
3459:
3460: DECL_RTL (decl)
3461: = assign_stack_temp (DECL_MODE (decl),
3462: ((TREE_INT_CST_LOW (DECL_SIZE (decl))
3463: + BITS_PER_UNIT - 1)
3464: / BITS_PER_UNIT),
3465: 1);
3466:
3467: /* Set alignment we actually gave this decl. */
3468: DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3469: : GET_MODE_BITSIZE (DECL_MODE (decl)));
3470:
3471: if (oldaddr)
3472: {
3473: addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3474: if (addr != oldaddr)
3475: emit_move_insn (oldaddr, addr);
3476: }
3477:
3478: /* If this is a memory ref that contains aggregate components,
3479: mark it as such for cse and loop optimize. */
3480: MEM_IN_STRUCT_P (DECL_RTL (decl))
3481: = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
3482: || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
3483: || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
3484: || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE);
3485: #if 0
3486: /* If this is in memory because of -ffloat-store,
3487: set the volatile bit, to prevent optimizations from
3488: undoing the effects. */
3489: if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3490: MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3491: #endif
3492: }
3493: else
3494: /* Dynamic-size object: must push space on the stack. */
3495: {
3496: rtx address, size;
3497:
3498: /* Record the stack pointer on entry to block, if have
3499: not already done so. */
3500: if (thisblock->data.block.stack_level == 0)
3501: {
3502: do_pending_stack_adjust ();
3503: emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3504: &thisblock->data.block.stack_level,
3505: thisblock->data.block.first_insn);
3506: stack_block_stack = thisblock;
3507: }
3508:
3509: /* Compute the variable's size, in bytes. */
3510: size = expand_expr (size_binop (CEIL_DIV_EXPR,
3511: DECL_SIZE (decl),
3512: size_int (BITS_PER_UNIT)),
3513: NULL_RTX, VOIDmode, 0);
3514: free_temp_slots ();
3515:
3516: /* This is equivalent to calling alloca. */
3517: current_function_calls_alloca = 1;
3518:
3519: /* Allocate space on the stack for the variable. */
3520: address = allocate_dynamic_stack_space (size, NULL_RTX,
3521: DECL_ALIGN (decl));
3522:
3523: if (nonlocal_goto_handler_slot != 0)
3524: emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
3525:
3526: /* Reference the variable indirect through that rtx. */
3527: DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl), address);
3528:
3529: /* If this is a memory ref that contains aggregate components,
3530: mark it as such for cse and loop optimize. */
3531: MEM_IN_STRUCT_P (DECL_RTL (decl))
3532: = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
3533: || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
3534: || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
3535: || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE);
3536:
3537: /* Indicate the alignment we actually gave this variable. */
3538: #ifdef STACK_BOUNDARY
3539: DECL_ALIGN (decl) = STACK_BOUNDARY;
3540: #else
3541: DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3542: #endif
3543: }
3544:
3545: if (TREE_THIS_VOLATILE (decl))
3546: MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3547: #if 0 /* A variable is not necessarily unchanging
3548: just because it is const. RTX_UNCHANGING_P
3549: means no change in the function,
3550: not merely no change in the variable's scope.
3551: It is correct to set RTX_UNCHANGING_P if the variable's scope
3552: is the whole function. There's no convenient way to test that. */
3553: if (TREE_READONLY (decl))
3554: RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3555: #endif
3556:
3557: /* If doing stupid register allocation, make sure life of any
3558: register variable starts here, at the start of its scope. */
3559:
3560: if (obey_regdecls)
3561: use_variable (DECL_RTL (decl));
3562: }
3563:
3564:
3565: /* Generate code for the automatic variable declaration DECL. For
3566: most variables this just means we give it a stack offset. The
3567: compiler sometimes emits cleanups without variables and we will
3568: have to deal with those too. */
3569:
3570: void
3571: bc_expand_decl (decl, cleanup)
3572: tree decl;
3573: tree cleanup;
3574: {
3575: tree type;
3576:
3577: if (!decl)
3578: {
3579: /* A cleanup with no variable. */
3580: if (!cleanup)
3581: abort ();
3582:
3583: return;
3584: }
3585:
3586: /* Only auto variables need any work. */
3587: if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3588: return;
3589:
3590: type = TREE_TYPE (decl);
3591:
3592: if (type == error_mark_node)
3593: DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3594:
3595: else if (DECL_SIZE (decl) == 0)
3596:
3597: /* Variable with incomplete type. The stack offset herein will be
3598: fixed later in expand_decl_init (). */
3599: DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3600:
3601: else if (TREE_CONSTANT (DECL_SIZE (decl)))
3602: {
3603: DECL_RTL (decl) = bc_allocate_local (TREE_INT_CST_LOW (DECL_SIZE (decl)) / BITS_PER_UNIT,
3604: DECL_ALIGN (decl));
3605: }
3606: else
3607: DECL_RTL (decl) = bc_allocate_variable_array (DECL_SIZE (decl));
3608: }
3609:
3610: /* Emit code to perform the initialization of a declaration DECL. */
3611:
3612: void
3613: expand_decl_init (decl)
3614: tree decl;
3615: {
3616: int was_used = TREE_USED (decl);
3617:
3618: /* If this is a CONST_DECL, we don't have to generate any code, but
3619: if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3620: to be set while in the obstack containing the constant. If we don't
3621: do this, we can lose if we have functions nested three deep and the middle
3622: function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3623: the innermost function is the first to expand that STRING_CST. */
3624: if (TREE_CODE (decl) == CONST_DECL)
3625: {
3626: if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3627: expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3628: EXPAND_INITIALIZER);
3629: return;
3630: }
3631:
3632: if (TREE_STATIC (decl))
3633: return;
3634:
3635: /* Compute and store the initial value now. */
3636:
3637: if (DECL_INITIAL (decl) == error_mark_node)
3638: {
3639: enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3640: if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3641: || code == POINTER_TYPE)
3642: expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3643: 0, 0);
3644: emit_queue ();
3645: }
3646: else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3647: {
3648: emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3649: expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3650: emit_queue ();
3651: }
3652:
3653: /* Don't let the initialization count as "using" the variable. */
3654: TREE_USED (decl) = was_used;
3655:
3656: /* Free any temporaries we made while initializing the decl. */
3657: free_temp_slots ();
3658: }
3659:
3660: /* Expand initialization for variable-sized types. Allocate array
3661: using newlocalSI and set local variable, which is a pointer to the
3662: storage. */
3663:
3664: bc_expand_variable_local_init (decl)
3665: tree decl;
3666: {
3667: /* Evaluate size expression and coerce to SI */
3668: bc_expand_expr (DECL_SIZE (decl));
3669:
3670: /* Type sizes are always (?) of TREE_CODE INTEGER_CST, so
3671: no coercion is necessary (?) */
3672:
3673: /* emit_typecode_conversion (preferred_typecode (TYPE_MODE (DECL_SIZE (decl)),
3674: TREE_UNSIGNED (DECL_SIZE (decl))), SIcode); */
3675:
3676: /* Emit code to allocate array */
3677: bc_emit_instruction (newlocalSI);
3678:
3679: /* Store array pointer in local variable. This is the only instance
3680: where we actually want the address of the pointer to the
3681: variable-size block, rather than the pointer itself. We avoid
3682: using expand_address() since that would cause the pointer to be
3683: pushed rather than its address. Hence the hard-coded reference;
3684: notice also that the variable is always local (no global
3685: variable-size type variables). */
3686:
3687: bc_load_localaddr (DECL_RTL (decl));
3688: bc_emit_instruction (storeP);
3689: }
3690:
3691:
3692: /* Emit code to initialize a declaration. */
3693: void
3694: bc_expand_decl_init (decl)
3695: tree decl;
3696: {
3697: int org_stack_depth;
3698:
3699: /* Statical initializers are handled elsewhere */
3700:
3701: if (TREE_STATIC (decl))
3702: return;
3703:
3704: /* Memory original stack depth */
3705: org_stack_depth = stack_depth;
3706:
3707: /* If the type is variable-size, we first create its space (we ASSUME
3708: it CAN'T be static). We do this regardless of whether there's an
3709: initializer assignment or not. */
3710:
3711: if (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
3712: bc_expand_variable_local_init (decl);
3713:
3714: /* Expand initializer assignment */
3715: if (DECL_INITIAL (decl) == error_mark_node)
3716: {
3717: enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3718:
3719: if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3720: || code == POINTER_TYPE)
3721:
3722: expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3723: }
3724: else if (DECL_INITIAL (decl))
3725: expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3726:
3727: /* Restore stack depth */
3728: if (org_stack_depth > stack_depth)
3729: abort ();
3730:
3731: bc_adjust_stack (stack_depth - org_stack_depth);
3732: }
3733:
3734:
3735: /* CLEANUP is an expression to be executed at exit from this binding contour;
3736: for example, in C++, it might call the destructor for this variable.
3737:
3738: If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3739: either before or after calling `expand_decl' but before compiling
3740: any subsequent expressions. This is because CLEANUP may be expanded
3741: more than once, on different branches of execution.
3742: For the same reason, CLEANUP may not contain a CALL_EXPR
3743: except as its topmost node--else `preexpand_calls' would get confused.
3744:
3745: If CLEANUP is nonzero and DECL is zero, we record a cleanup
3746: that is not associated with any particular variable. */
3747:
3748: int
3749: expand_decl_cleanup (decl, cleanup)
3750: tree decl, cleanup;
3751: {
3752: struct nesting *thisblock = block_stack;
3753:
3754: /* Error if we are not in any block. */
3755: if (thisblock == 0)
3756: return 0;
3757:
3758: /* Record the cleanup if there is one. */
3759:
3760: if (cleanup != 0)
3761: {
3762: thisblock->data.block.cleanups
3763: = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3764: /* If this block has a cleanup, it belongs in stack_block_stack. */
3765: stack_block_stack = thisblock;
3766: }
3767: return 1;
3768: }
3769:
3770: /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3771: DECL_ELTS is the list of elements that belong to DECL's type.
3772: In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3773:
3774: void
3775: expand_anon_union_decl (decl, cleanup, decl_elts)
3776: tree decl, cleanup, decl_elts;
3777: {
3778: struct nesting *thisblock = block_stack;
3779: rtx x;
3780:
3781: expand_decl (decl, cleanup);
3782: x = DECL_RTL (decl);
3783:
3784: while (decl_elts)
3785: {
3786: tree decl_elt = TREE_VALUE (decl_elts);
3787: tree cleanup_elt = TREE_PURPOSE (decl_elts);
3788: enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3789:
3790: /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3791: instead create a new MEM rtx with the proper mode. */
3792: if (GET_CODE (x) == MEM)
3793: {
3794: if (mode == GET_MODE (x))
3795: DECL_RTL (decl_elt) = x;
3796: else
3797: {
3798: DECL_RTL (decl_elt) = gen_rtx (MEM, mode, copy_rtx (XEXP (x, 0)));
3799: MEM_IN_STRUCT_P (DECL_RTL (decl_elt)) = MEM_IN_STRUCT_P (x);
3800: RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
3801: }
3802: }
3803: else if (GET_CODE (x) == REG)
3804: {
3805: if (mode == GET_MODE (x))
3806: DECL_RTL (decl_elt) = x;
3807: else
3808: DECL_RTL (decl_elt) = gen_rtx (SUBREG, mode, x, 0);
3809: }
3810: else
3811: abort ();
3812:
3813: /* Record the cleanup if there is one. */
3814:
3815: if (cleanup != 0)
3816: thisblock->data.block.cleanups
3817: = temp_tree_cons (decl_elt, cleanup_elt,
3818: thisblock->data.block.cleanups);
3819:
3820: decl_elts = TREE_CHAIN (decl_elts);
3821: }
3822: }
3823:
3824: /* Expand a list of cleanups LIST.
3825: Elements may be expressions or may be nested lists.
3826:
3827: If DONT_DO is nonnull, then any list-element
3828: whose TREE_PURPOSE matches DONT_DO is omitted.
3829: This is sometimes used to avoid a cleanup associated with
3830: a value that is being returned out of the scope. */
3831:
3832: static void
3833: expand_cleanups (list, dont_do)
3834: tree list;
3835: tree dont_do;
3836: {
3837: tree tail;
3838: for (tail = list; tail; tail = TREE_CHAIN (tail))
3839: if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
3840: {
3841: if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3842: expand_cleanups (TREE_VALUE (tail), dont_do);
3843: else
3844: {
3845: /* Cleanups may be run multiple times. For example,
3846: when exiting a binding contour, we expand the
3847: cleanups associated with that contour. When a goto
3848: within that binding contour has a target outside that
3849: contour, it will expand all cleanups from its scope to
3850: the target. Though the cleanups are expanded multiple
3851: times, the control paths are non-overlapping so the
3852: cleanups will not be executed twice. */
3853: expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3854: free_temp_slots ();
3855: }
3856: }
3857: }
3858:
3859: /* Move all cleanups from the current block_stack
3860: to the containing block_stack, where they are assumed to
3861: have been created. If anything can cause a temporary to
3862: be created, but not expanded for more than one level of
3863: block_stacks, then this code will have to change. */
3864:
3865: void
3866: move_cleanups_up ()
3867: {
3868: struct nesting *block = block_stack;
3869: struct nesting *outer = block->next;
3870:
3871: outer->data.block.cleanups
3872: = chainon (block->data.block.cleanups,
3873: outer->data.block.cleanups);
3874: block->data.block.cleanups = 0;
3875: }
3876:
3877: tree
3878: last_cleanup_this_contour ()
3879: {
3880: if (block_stack == 0)
3881: return 0;
3882:
3883: return block_stack->data.block.cleanups;
3884: }
3885:
3886: /* Return 1 if there are any pending cleanups at this point.
3887: If THIS_CONTOUR is nonzero, check the current contour as well.
3888: Otherwise, look only at the contours that enclose this one. */
3889:
3890: int
3891: any_pending_cleanups (this_contour)
3892: int this_contour;
3893: {
3894: struct nesting *block;
3895:
3896: if (block_stack == 0)
3897: return 0;
3898:
3899: if (this_contour && block_stack->data.block.cleanups != NULL)
3900: return 1;
3901: if (block_stack->data.block.cleanups == 0
3902: && (block_stack->data.block.outer_cleanups == 0
3903: #if 0
3904: || block_stack->data.block.outer_cleanups == empty_cleanup_list
3905: #endif
3906: ))
3907: return 0;
3908:
3909: for (block = block_stack->next; block; block = block->next)
3910: if (block->data.block.cleanups != 0)
3911: return 1;
3912:
3913: return 0;
3914: }
3915:
3916: /* Enter a case (Pascal) or switch (C) statement.
3917: Push a block onto case_stack and nesting_stack
3918: to accumulate the case-labels that are seen
3919: and to record the labels generated for the statement.
3920:
3921: EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3922: Otherwise, this construct is transparent for `exit_something'.
3923:
3924: EXPR is the index-expression to be dispatched on.
3925: TYPE is its nominal type. We could simply convert EXPR to this type,
3926: but instead we take short cuts. */
3927:
3928: void
3929: expand_start_case (exit_flag, expr, type, printname)
3930: int exit_flag;
3931: tree expr;
3932: tree type;
3933: char *printname;
3934: {
3935: register struct nesting *thiscase = ALLOC_NESTING ();
3936:
3937: /* Make an entry on case_stack for the case we are entering. */
3938:
3939: thiscase->next = case_stack;
3940: thiscase->all = nesting_stack;
3941: thiscase->depth = ++nesting_depth;
3942: thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3943: thiscase->data.case_stmt.case_list = 0;
3944: thiscase->data.case_stmt.index_expr = expr;
3945: thiscase->data.case_stmt.nominal_type = type;
3946: thiscase->data.case_stmt.default_label = 0;
3947: thiscase->data.case_stmt.num_ranges = 0;
3948: thiscase->data.case_stmt.printname = printname;
3949: thiscase->data.case_stmt.seenlabel = 0;
3950: case_stack = thiscase;
3951: nesting_stack = thiscase;
3952:
3953: if (output_bytecode)
3954: {
3955: bc_expand_start_case (thiscase, expr, type, printname);
3956: return;
3957: }
3958:
3959: do_pending_stack_adjust ();
3960:
3961: /* Make sure case_stmt.start points to something that won't
3962: need any transformation before expand_end_case. */
3963: if (GET_CODE (get_last_insn ()) != NOTE)
3964: emit_note (NULL_PTR, NOTE_INSN_DELETED);
3965:
3966: thiscase->data.case_stmt.start = get_last_insn ();
3967: }
3968:
3969:
3970: /* Enter a case statement. It is assumed that the caller has pushed
3971: the current context onto the case stack. */
3972: void
3973: bc_expand_start_case (thiscase, expr, type, printname)
3974: struct nesting *thiscase;
3975: tree expr;
3976: tree type;
3977: char *printname;
3978: {
3979: bc_expand_expr (expr);
3980: bc_expand_conversion (TREE_TYPE (expr), type);
3981:
3982: /* For cases, the skip is a place we jump to that's emitted after
3983: the size of the jump table is known. */
3984:
3985: thiscase->data.case_stmt.skip_label = gen_label_rtx ();
3986: bc_emit_bytecode (jump);
3987: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
3988:
3989: #ifdef DEBUG_PRINT_CODE
3990: fputc ('\n', stderr);
3991: #endif
3992: }
3993:
3994:
3995: /* Start a "dummy case statement" within which case labels are invalid
3996: and are not connected to any larger real case statement.
3997: This can be used if you don't want to let a case statement jump
3998: into the middle of certain kinds of constructs. */
3999:
4000: void
4001: expand_start_case_dummy ()
4002: {
4003: register struct nesting *thiscase = ALLOC_NESTING ();
4004:
4005: /* Make an entry on case_stack for the dummy. */
4006:
4007: thiscase->next = case_stack;
4008: thiscase->all = nesting_stack;
4009: thiscase->depth = ++nesting_depth;
4010: thiscase->exit_label = 0;
4011: thiscase->data.case_stmt.case_list = 0;
4012: thiscase->data.case_stmt.start = 0;
4013: thiscase->data.case_stmt.nominal_type = 0;
4014: thiscase->data.case_stmt.default_label = 0;
4015: thiscase->data.case_stmt.num_ranges = 0;
4016: case_stack = thiscase;
4017: nesting_stack = thiscase;
4018: }
4019:
4020: /* End a dummy case statement. */
4021:
4022: void
4023: expand_end_case_dummy ()
4024: {
4025: POPSTACK (case_stack);
4026: }
4027:
4028: /* Return the data type of the index-expression
4029: of the innermost case statement, or null if none. */
4030:
4031: tree
4032: case_index_expr_type ()
4033: {
4034: if (case_stack)
4035: return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4036: return 0;
4037: }
4038:
4039: /* Accumulate one case or default label inside a case or switch statement.
4040: VALUE is the value of the case (a null pointer, for a default label).
4041: The function CONVERTER, when applied to arguments T and V,
4042: converts the value V to the type T.
4043:
4044: If not currently inside a case or switch statement, return 1 and do
4045: nothing. The caller will print a language-specific error message.
4046: If VALUE is a duplicate or overlaps, return 2 and do nothing
4047: except store the (first) duplicate node in *DUPLICATE.
4048: If VALUE is out of range, return 3 and do nothing.
4049: If we are jumping into the scope of a cleaup or var-sized array, return 5.
4050: Return 0 on success.
4051:
4052: Extended to handle range statements. */
4053:
4054: int
4055: pushcase (value, converter, label, duplicate)
4056: register tree value;
4057: tree (*converter) PROTO((tree, tree));
4058: register tree label;
4059: tree *duplicate;
4060: {
4061: register struct case_node **l;
4062: register struct case_node *n;
4063: tree index_type;
4064: tree nominal_type;
4065:
4066: if (output_bytecode)
4067: return bc_pushcase (value, label);
4068:
4069: /* Fail if not inside a real case statement. */
4070: if (! (case_stack && case_stack->data.case_stmt.start))
4071: return 1;
4072:
4073: if (stack_block_stack
4074: && stack_block_stack->depth > case_stack->depth)
4075: return 5;
4076:
4077: index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4078: nominal_type = case_stack->data.case_stmt.nominal_type;
4079:
4080: /* If the index is erroneous, avoid more problems: pretend to succeed. */
4081: if (index_type == error_mark_node)
4082: return 0;
4083:
4084: /* Convert VALUE to the type in which the comparisons are nominally done. */
4085: if (value != 0)
4086: value = (*converter) (nominal_type, value);
4087:
4088: /* If this is the first label, warn if any insns have been emitted. */
4089: if (case_stack->data.case_stmt.seenlabel == 0)
4090: {
4091: rtx insn;
4092: for (insn = case_stack->data.case_stmt.start;
4093: insn;
4094: insn = NEXT_INSN (insn))
4095: {
4096: if (GET_CODE (insn) == CODE_LABEL)
4097: break;
4098: if (GET_CODE (insn) != NOTE
4099: && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4100: {
4101: warning ("unreachable code at beginning of %s",
4102: case_stack->data.case_stmt.printname);
4103: break;
4104: }
4105: }
4106: }
4107: case_stack->data.case_stmt.seenlabel = 1;
4108:
4109: /* Fail if this value is out of range for the actual type of the index
4110: (which may be narrower than NOMINAL_TYPE). */
4111: if (value != 0 && ! int_fits_type_p (value, index_type))
4112: return 3;
4113:
4114: /* Fail if this is a duplicate or overlaps another entry. */
4115: if (value == 0)
4116: {
4117: if (case_stack->data.case_stmt.default_label != 0)
4118: {
4119: *duplicate = case_stack->data.case_stmt.default_label;
4120: return 2;
4121: }
4122: case_stack->data.case_stmt.default_label = label;
4123: }
4124: else
4125: {
4126: /* Find the elt in the chain before which to insert the new value,
4127: to keep the chain sorted in increasing order.
4128: But report an error if this element is a duplicate. */
4129: for (l = &case_stack->data.case_stmt.case_list;
4130: /* Keep going past elements distinctly less than VALUE. */
4131: *l != 0 && tree_int_cst_lt ((*l)->high, value);
4132: l = &(*l)->right)
4133: ;
4134: if (*l)
4135: {
4136: /* Element we will insert before must be distinctly greater;
4137: overlap means error. */
4138: if (! tree_int_cst_lt (value, (*l)->low))
4139: {
4140: *duplicate = (*l)->code_label;
4141: return 2;
4142: }
4143: }
4144:
4145: /* Add this label to the chain, and succeed.
4146: Copy VALUE so it is on temporary rather than momentary
4147: obstack and will thus survive till the end of the case statement. */
4148: n = (struct case_node *) oballoc (sizeof (struct case_node));
4149: n->left = 0;
4150: n->right = *l;
4151: n->high = n->low = copy_node (value);
4152: n->code_label = label;
4153: *l = n;
4154: }
4155:
4156: expand_label (label);
4157: return 0;
4158: }
4159:
4160: /* Like pushcase but this case applies to all values
4161: between VALUE1 and VALUE2 (inclusive).
4162: The return value is the same as that of pushcase
4163: but there is one additional error code:
4164: 4 means the specified range was empty. */
4165:
4166: int
4167: pushcase_range (value1, value2, converter, label, duplicate)
4168: register tree value1, value2;
4169: tree (*converter) PROTO((tree, tree));
4170: register tree label;
4171: tree *duplicate;
4172: {
4173: register struct case_node **l;
4174: register struct case_node *n;
4175: tree index_type;
4176: tree nominal_type;
4177:
4178: /* Fail if not inside a real case statement. */
4179: if (! (case_stack && case_stack->data.case_stmt.start))
4180: return 1;
4181:
4182: if (stack_block_stack
4183: && stack_block_stack->depth > case_stack->depth)
4184: return 5;
4185:
4186: index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4187: nominal_type = case_stack->data.case_stmt.nominal_type;
4188:
4189: /* If the index is erroneous, avoid more problems: pretend to succeed. */
4190: if (index_type == error_mark_node)
4191: return 0;
4192:
4193: /* If this is the first label, warn if any insns have been emitted. */
4194: if (case_stack->data.case_stmt.seenlabel == 0)
4195: {
4196: rtx insn;
4197: for (insn = case_stack->data.case_stmt.start;
4198: insn;
4199: insn = NEXT_INSN (insn))
4200: {
4201: if (GET_CODE (insn) == CODE_LABEL)
4202: break;
4203: if (GET_CODE (insn) != NOTE
4204: && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4205: {
4206: warning ("unreachable code at beginning of %s",
4207: case_stack->data.case_stmt.printname);
4208: break;
4209: }
4210: }
4211: }
4212: case_stack->data.case_stmt.seenlabel = 1;
4213:
4214: /* Convert VALUEs to type in which the comparisons are nominally done. */
4215: if (value1 == 0) /* Negative infinity. */
4216: value1 = TYPE_MIN_VALUE(index_type);
4217: value1 = (*converter) (nominal_type, value1);
4218:
4219: if (value2 == 0) /* Positive infinity. */
4220: value2 = TYPE_MAX_VALUE(index_type);
4221: value2 = (*converter) (nominal_type, value2);
4222:
4223: /* Fail if these values are out of range. */
4224: if (! int_fits_type_p (value1, index_type))
4225: return 3;
4226:
4227: if (! int_fits_type_p (value2, index_type))
4228: return 3;
4229:
4230: /* Fail if the range is empty. */
4231: if (tree_int_cst_lt (value2, value1))
4232: return 4;
4233:
4234: /* If the bounds are equal, turn this into the one-value case. */
4235: if (tree_int_cst_equal (value1, value2))
4236: return pushcase (value1, converter, label, duplicate);
4237:
4238: /* Find the elt in the chain before which to insert the new value,
4239: to keep the chain sorted in increasing order.
4240: But report an error if this element is a duplicate. */
4241: for (l = &case_stack->data.case_stmt.case_list;
4242: /* Keep going past elements distinctly less than this range. */
4243: *l != 0 && tree_int_cst_lt ((*l)->high, value1);
4244: l = &(*l)->right)
4245: ;
4246: if (*l)
4247: {
4248: /* Element we will insert before must be distinctly greater;
4249: overlap means error. */
4250: if (! tree_int_cst_lt (value2, (*l)->low))
4251: {
4252: *duplicate = (*l)->code_label;
4253: return 2;
4254: }
4255: }
4256:
4257: /* Add this label to the chain, and succeed.
4258: Copy VALUE1, VALUE2 so they are on temporary rather than momentary
4259: obstack and will thus survive till the end of the case statement. */
4260:
4261: n = (struct case_node *) oballoc (sizeof (struct case_node));
4262: n->left = 0;
4263: n->right = *l;
4264: n->low = copy_node (value1);
4265: n->high = copy_node (value2);
4266: n->code_label = label;
4267: *l = n;
4268:
4269: expand_label (label);
4270:
4271: case_stack->data.case_stmt.num_ranges++;
4272:
4273: return 0;
4274: }
4275:
4276:
4277: /* Accumulate one case or default label; VALUE is the value of the
4278: case, or nil for a default label. If not currently inside a case,
4279: return 1 and do nothing. If VALUE is a duplicate or overlaps, return
4280: 2 and do nothing. If VALUE is out of range, return 3 and do nothing.
4281: Return 0 on success. This function is a leftover from the earlier
4282: bytecode compiler, which was based on gcc 1.37. It should be
4283: merged into pushcase. */
4284:
4285: int
4286: bc_pushcase (value, label)
4287: tree value;
4288: tree label;
4289: {
4290: struct nesting *thiscase = case_stack;
4291: struct case_node *case_label, *new_label;
4292:
4293: if (! thiscase)
4294: return 1;
4295:
4296: /* Fail if duplicate, overlap, or out of type range. */
4297: if (value)
4298: {
4299: value = convert (thiscase->data.case_stmt.nominal_type, value);
4300: if (! int_fits_type_p (value, thiscase->data.case_stmt.nominal_type))
4301: return 3;
4302:
4303: for (case_label = thiscase->data.case_stmt.case_list;
4304: case_label->left; case_label = case_label->left)
4305: if (! tree_int_cst_lt (case_label->left->high, value))
4306: break;
4307:
4308: if (case_label != thiscase->data.case_stmt.case_list
4309: && ! tree_int_cst_lt (case_label->high, value)
4310: || case_label->left && ! tree_int_cst_lt (value, case_label->left->low))
4311: return 2;
4312:
4313: new_label = (struct case_node *) oballoc (sizeof (struct case_node));
4314: new_label->low = new_label->high = copy_node (value);
4315: new_label->code_label = label;
4316: new_label->left = case_label->left;
4317:
4318: case_label->left = new_label;
4319: thiscase->data.case_stmt.num_ranges++;
4320: }
4321: else
4322: {
4323: if (thiscase->data.case_stmt.default_label)
4324: return 2;
4325: thiscase->data.case_stmt.default_label = label;
4326: }
4327:
4328: expand_label (label);
4329: return 0;
4330: }
4331:
4332: /* Called when the index of a switch statement is an enumerated type
4333: and there is no default label.
4334:
4335: Checks that all enumeration literals are covered by the case
4336: expressions of a switch. Also, warn if there are any extra
4337: switch cases that are *not* elements of the enumerated type.
4338:
4339: If all enumeration literals were covered by the case expressions,
4340: turn one of the expressions into the default expression since it should
4341: not be possible to fall through such a switch. */
4342:
4343: void
4344: check_for_full_enumeration_handling (type)
4345: tree type;
4346: {
4347: register struct case_node *n;
4348: register struct case_node **l;
4349: register tree chain;
4350: int all_values = 1;
4351:
4352: if (output_bytecode)
4353: {
4354: bc_check_for_full_enumeration_handling (type);
4355: return;
4356: }
4357:
4358: /* The time complexity of this loop is currently O(N * M), with
4359: N being the number of members in the enumerated type, and
4360: M being the number of case expressions in the switch. */
4361:
4362: for (chain = TYPE_VALUES (type);
4363: chain;
4364: chain = TREE_CHAIN (chain))
4365: {
4366: /* Find a match between enumeral and case expression, if possible.
4367: Quit looking when we've gone too far (since case expressions
4368: are kept sorted in ascending order). Warn about enumerators not
4369: handled in the switch statement case expression list. */
4370:
4371: for (n = case_stack->data.case_stmt.case_list;
4372: n && tree_int_cst_lt (n->high, TREE_VALUE (chain));
4373: n = n->right)
4374: ;
4375:
4376: if (!n || tree_int_cst_lt (TREE_VALUE (chain), n->low))
4377: {
4378: if (warn_switch)
4379: warning ("enumeration value `%s' not handled in switch",
4380: IDENTIFIER_POINTER (TREE_PURPOSE (chain)));
4381: all_values = 0;
4382: }
4383: }
4384:
4385: /* Now we go the other way around; we warn if there are case
4386: expressions that don't correspond to enumerators. This can
4387: occur since C and C++ don't enforce type-checking of
4388: assignments to enumeration variables. */
4389:
4390: if (warn_switch)
4391: for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
4392: {
4393: for (chain = TYPE_VALUES (type);
4394: chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
4395: chain = TREE_CHAIN (chain))
4396: ;
4397:
4398: if (!chain)
4399: {
4400: if (TYPE_NAME (type) == 0)
4401: warning ("case value `%d' not in enumerated type",
4402: TREE_INT_CST_LOW (n->low));
4403: else
4404: warning ("case value `%d' not in enumerated type `%s'",
4405: TREE_INT_CST_LOW (n->low),
4406: IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4407: == IDENTIFIER_NODE)
4408: ? TYPE_NAME (type)
4409: : DECL_NAME (TYPE_NAME (type))));
4410: }
4411: if (!tree_int_cst_equal (n->low, n->high))
4412: {
4413: for (chain = TYPE_VALUES (type);
4414: chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
4415: chain = TREE_CHAIN (chain))
4416: ;
4417:
4418: if (!chain)
4419: {
4420: if (TYPE_NAME (type) == 0)
4421: warning ("case value `%d' not in enumerated type",
4422: TREE_INT_CST_LOW (n->high));
4423: else
4424: warning ("case value `%d' not in enumerated type `%s'",
4425: TREE_INT_CST_LOW (n->high),
4426: IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4427: == IDENTIFIER_NODE)
4428: ? TYPE_NAME (type)
4429: : DECL_NAME (TYPE_NAME (type))));
4430: }
4431: }
4432: }
4433:
4434: #if 0
4435: /* ??? This optimization is disabled because it causes valid programs to
4436: fail. ANSI C does not guarantee that an expression with enum type
4437: will have a value that is the same as one of the enumation literals. */
4438:
4439: /* If all values were found as case labels, make one of them the default
4440: label. Thus, this switch will never fall through. We arbitrarily pick
4441: the last one to make the default since this is likely the most
4442: efficient choice. */
4443:
4444: if (all_values)
4445: {
4446: for (l = &case_stack->data.case_stmt.case_list;
4447: (*l)->right != 0;
4448: l = &(*l)->right)
4449: ;
4450:
4451: case_stack->data.case_stmt.default_label = (*l)->code_label;
4452: *l = 0;
4453: }
4454: #endif /* 0 */
4455: }
4456:
4457:
4458: /* Check that all enumeration literals are covered by the case
4459: expressions of a switch. Also warn if there are any cases
4460: that are not elements of the enumerated type. */
4461: void
4462: bc_check_for_full_enumeration_handling (type)
4463: tree type;
4464: {
4465: struct nesting *thiscase = case_stack;
4466: struct case_node *c;
4467: tree e;
4468:
4469: /* Check for enums not handled. */
4470: for (e = TYPE_VALUES (type); e; e = TREE_CHAIN (e))
4471: {
4472: for (c = thiscase->data.case_stmt.case_list->left;
4473: c && tree_int_cst_lt (c->high, TREE_VALUE (e));
4474: c = c->left)
4475: ;
4476: if (! (c && tree_int_cst_equal (c->low, TREE_VALUE (e))))
4477: warning ("enumerated value `%s' not handled in switch",
4478: IDENTIFIER_POINTER (TREE_PURPOSE (e)));
4479: }
4480:
4481: /* Check for cases not in the enumeration. */
4482: for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
4483: {
4484: for (e = TYPE_VALUES (type);
4485: e && !tree_int_cst_equal (c->low, TREE_VALUE (e));
4486: e = TREE_CHAIN (e))
4487: ;
4488: if (! e)
4489: warning ("case value `%d' not in enumerated type `%s'",
4490: TREE_INT_CST_LOW (c->low),
4491: IDENTIFIER_POINTER (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE
4492: ? TYPE_NAME (type)
4493: : DECL_NAME (TYPE_NAME (type))));
4494: }
4495: }
4496:
4497: /* Terminate a case (Pascal) or switch (C) statement
4498: in which ORIG_INDEX is the expression to be tested.
4499: Generate the code to test it and jump to the right place. */
4500:
4501: void
4502: expand_end_case (orig_index)
4503: tree orig_index;
4504: {
4505: tree minval, maxval, range, orig_minval;
4506: rtx default_label = 0;
4507: register struct case_node *n;
4508: int count;
4509: rtx index;
4510: rtx table_label;
4511: int ncases;
4512: rtx *labelvec;
4513: register int i;
4514: rtx before_case;
4515: register struct nesting *thiscase = case_stack;
4516: tree index_expr;
4517: int unsignedp;
4518:
4519: if (output_bytecode)
4520: {
4521: bc_expand_end_case (orig_index);
4522: return;
4523: }
4524:
4525: table_label = gen_label_rtx ();
4526: index_expr = thiscase->data.case_stmt.index_expr;
4527: unsignedp = TREE_UNSIGNED (TREE_TYPE (index_expr));
4528:
4529: do_pending_stack_adjust ();
4530:
4531: /* An ERROR_MARK occurs for various reasons including invalid data type. */
4532: if (TREE_TYPE (index_expr) != error_mark_node)
4533: {
4534: /* If switch expression was an enumerated type, check that all
4535: enumeration literals are covered by the cases.
4536: No sense trying this if there's a default case, however. */
4537:
4538: if (!thiscase->data.case_stmt.default_label
4539: && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
4540: && TREE_CODE (index_expr) != INTEGER_CST)
4541: check_for_full_enumeration_handling (TREE_TYPE (orig_index));
4542:
4543: /* If this is the first label, warn if any insns have been emitted. */
4544: if (thiscase->data.case_stmt.seenlabel == 0)
4545: {
4546: rtx insn;
4547: for (insn = get_last_insn ();
4548: insn != case_stack->data.case_stmt.start;
4549: insn = PREV_INSN (insn))
4550: if (GET_CODE (insn) != NOTE
4551: && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn))!= USE))
4552: {
4553: warning ("unreachable code at beginning of %s",
4554: case_stack->data.case_stmt.printname);
4555: break;
4556: }
4557: }
4558:
4559: /* If we don't have a default-label, create one here,
4560: after the body of the switch. */
4561: if (thiscase->data.case_stmt.default_label == 0)
4562: {
4563: thiscase->data.case_stmt.default_label
4564: = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4565: expand_label (thiscase->data.case_stmt.default_label);
4566: }
4567: default_label = label_rtx (thiscase->data.case_stmt.default_label);
4568:
4569: before_case = get_last_insn ();
4570:
4571: /* Simplify the case-list before we count it. */
4572: group_case_nodes (thiscase->data.case_stmt.case_list);
4573:
4574: /* Get upper and lower bounds of case values.
4575: Also convert all the case values to the index expr's data type. */
4576:
4577: count = 0;
4578: for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4579: {
4580: /* Check low and high label values are integers. */
4581: if (TREE_CODE (n->low) != INTEGER_CST)
4582: abort ();
4583: if (TREE_CODE (n->high) != INTEGER_CST)
4584: abort ();
4585:
4586: n->low = convert (TREE_TYPE (index_expr), n->low);
4587: n->high = convert (TREE_TYPE (index_expr), n->high);
4588:
4589: /* Count the elements and track the largest and smallest
4590: of them (treating them as signed even if they are not). */
4591: if (count++ == 0)
4592: {
4593: minval = n->low;
4594: maxval = n->high;
4595: }
4596: else
4597: {
4598: if (INT_CST_LT (n->low, minval))
4599: minval = n->low;
4600: if (INT_CST_LT (maxval, n->high))
4601: maxval = n->high;
4602: }
4603: /* A range counts double, since it requires two compares. */
4604: if (! tree_int_cst_equal (n->low, n->high))
4605: count++;
4606: }
4607:
4608: orig_minval = minval;
4609:
4610: /* Compute span of values. */
4611: if (count != 0)
4612: range = fold (build (MINUS_EXPR, TREE_TYPE (index_expr),
4613: maxval, minval));
4614:
4615: if (count == 0 || TREE_CODE (TREE_TYPE (index_expr)) == ERROR_MARK)
4616: {
4617: expand_expr (index_expr, const0_rtx, VOIDmode, 0);
4618: emit_queue ();
4619: emit_jump (default_label);
4620: }
4621:
4622: /* If range of values is much bigger than number of values,
4623: make a sequence of conditional branches instead of a dispatch.
4624: If the switch-index is a constant, do it this way
4625: because we can optimize it. */
4626:
4627: #ifndef CASE_VALUES_THRESHOLD
4628: #ifdef HAVE_casesi
4629: #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
4630: #else
4631: /* If machine does not have a case insn that compares the
4632: bounds, this means extra overhead for dispatch tables
4633: which raises the threshold for using them. */
4634: #define CASE_VALUES_THRESHOLD 5
4635: #endif /* HAVE_casesi */
4636: #endif /* CASE_VALUES_THRESHOLD */
4637:
4638: else if (TREE_INT_CST_HIGH (range) != 0
4639: || count < CASE_VALUES_THRESHOLD
4640: || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
4641: > 10 * count)
4642: || TREE_CODE (index_expr) == INTEGER_CST
4643: /* These will reduce to a constant. */
4644: || (TREE_CODE (index_expr) == CALL_EXPR
4645: && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
4646: && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
4647: && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
4648: || (TREE_CODE (index_expr) == COMPOUND_EXPR
4649: && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
4650: {
4651: index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4652:
4653: /* If the index is a short or char that we do not have
4654: an insn to handle comparisons directly, convert it to
4655: a full integer now, rather than letting each comparison
4656: generate the conversion. */
4657:
4658: if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
4659: && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
4660: == CODE_FOR_nothing))
4661: {
4662: enum machine_mode wider_mode;
4663: for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
4664: wider_mode = GET_MODE_WIDER_MODE (wider_mode))
4665: if (cmp_optab->handlers[(int) wider_mode].insn_code
4666: != CODE_FOR_nothing)
4667: {
4668: index = convert_to_mode (wider_mode, index, unsignedp);
4669: break;
4670: }
4671: }
4672:
4673: emit_queue ();
4674: do_pending_stack_adjust ();
4675:
4676: index = protect_from_queue (index, 0);
4677: if (GET_CODE (index) == MEM)
4678: index = copy_to_reg (index);
4679: if (GET_CODE (index) == CONST_INT
4680: || TREE_CODE (index_expr) == INTEGER_CST)
4681: {
4682: /* Make a tree node with the proper constant value
4683: if we don't already have one. */
4684: if (TREE_CODE (index_expr) != INTEGER_CST)
4685: {
4686: index_expr
4687: = build_int_2 (INTVAL (index),
4688: !unsignedp && INTVAL (index) >= 0 ? 0 : -1);
4689: index_expr = convert (TREE_TYPE (index_expr), index_expr);
4690: }
4691:
4692: /* For constant index expressions we need only
4693: issue a unconditional branch to the appropriate
4694: target code. The job of removing any unreachable
4695: code is left to the optimisation phase if the
4696: "-O" option is specified. */
4697: for (n = thiscase->data.case_stmt.case_list;
4698: n;
4699: n = n->right)
4700: {
4701: if (! tree_int_cst_lt (index_expr, n->low)
4702: && ! tree_int_cst_lt (n->high, index_expr))
4703: break;
4704: }
4705: if (n)
4706: emit_jump (label_rtx (n->code_label));
4707: else
4708: emit_jump (default_label);
4709: }
4710: else
4711: {
4712: /* If the index expression is not constant we generate
4713: a binary decision tree to select the appropriate
4714: target code. This is done as follows:
4715:
4716: The list of cases is rearranged into a binary tree,
4717: nearly optimal assuming equal probability for each case.
4718:
4719: The tree is transformed into RTL, eliminating
4720: redundant test conditions at the same time.
4721:
4722: If program flow could reach the end of the
4723: decision tree an unconditional jump to the
4724: default code is emitted. */
4725:
4726: use_cost_table
4727: = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
4728: && estimate_case_costs (thiscase->data.case_stmt.case_list));
4729: balance_case_nodes (&thiscase->data.case_stmt.case_list,
4730: NULL_PTR);
4731: emit_case_nodes (index, thiscase->data.case_stmt.case_list,
4732: default_label, TREE_TYPE (index_expr));
4733: emit_jump_if_reachable (default_label);
4734: }
4735: }
4736: else
4737: {
4738: int win = 0;
4739: #ifdef HAVE_casesi
4740: if (HAVE_casesi)
4741: {
4742: enum machine_mode index_mode = SImode;
4743: int index_bits = GET_MODE_BITSIZE (index_mode);
4744:
4745: /* Convert the index to SImode. */
4746: if (GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (index_expr)))
4747: > GET_MODE_BITSIZE (index_mode))
4748: {
4749: enum machine_mode omode = TYPE_MODE (TREE_TYPE (index_expr));
4750: rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
4751:
4752: /* We must handle the endpoints in the original mode. */
4753: index_expr = build (MINUS_EXPR, TREE_TYPE (index_expr),
4754: index_expr, minval);
4755: minval = integer_zero_node;
4756: index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4757: emit_cmp_insn (rangertx, index, LTU, NULL_RTX, omode, 1, 0);
4758: emit_jump_insn (gen_bltu (default_label));
4759: /* Now we can safely truncate. */
4760: index = convert_to_mode (index_mode, index, 0);
4761: }
4762: else
4763: {
4764: if (TYPE_MODE (TREE_TYPE (index_expr)) != index_mode)
4765: index_expr = convert (type_for_size (index_bits, 0),
4766: index_expr);
4767: index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4768: }
4769: emit_queue ();
4770: index = protect_from_queue (index, 0);
4771: do_pending_stack_adjust ();
4772:
4773: emit_jump_insn (gen_casesi (index, expand_expr (minval, NULL_RTX,
4774: VOIDmode, 0),
4775: expand_expr (range, NULL_RTX,
4776: VOIDmode, 0),
4777: table_label, default_label));
4778: win = 1;
4779: }
4780: #endif
4781: #ifdef HAVE_tablejump
4782: if (! win && HAVE_tablejump)
4783: {
4784: index_expr = convert (thiscase->data.case_stmt.nominal_type,
4785: fold (build (MINUS_EXPR,
4786: TREE_TYPE (index_expr),
4787: index_expr, minval)));
4788: index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4789: emit_queue ();
4790: index = protect_from_queue (index, 0);
4791: do_pending_stack_adjust ();
4792:
4793: do_tablejump (index, TYPE_MODE (TREE_TYPE (index_expr)),
4794: expand_expr (range, NULL_RTX, VOIDmode, 0),
4795: table_label, default_label);
4796: win = 1;
4797: }
4798: #endif
4799: if (! win)
4800: abort ();
4801:
4802: /* Get table of labels to jump to, in order of case index. */
4803:
4804: ncases = TREE_INT_CST_LOW (range) + 1;
4805: labelvec = (rtx *) alloca (ncases * sizeof (rtx));
4806: bzero (labelvec, ncases * sizeof (rtx));
4807:
4808: for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4809: {
4810: register HOST_WIDE_INT i
4811: = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
4812:
4813: while (1)
4814: {
4815: labelvec[i]
4816: = gen_rtx (LABEL_REF, Pmode, label_rtx (n->code_label));
4817: if (i + TREE_INT_CST_LOW (orig_minval)
4818: == TREE_INT_CST_LOW (n->high))
4819: break;
4820: i++;
4821: }
4822: }
4823:
4824: /* Fill in the gaps with the default. */
4825: for (i = 0; i < ncases; i++)
4826: if (labelvec[i] == 0)
4827: labelvec[i] = gen_rtx (LABEL_REF, Pmode, default_label);
4828:
4829: /* Output the table */
4830: emit_label (table_label);
4831:
4832: /* This would be a lot nicer if CASE_VECTOR_PC_RELATIVE
4833: were an expression, instead of an #ifdef/#ifndef. */
4834: if (
4835: #ifdef CASE_VECTOR_PC_RELATIVE
4836: 1 ||
4837: #endif
4838: #ifdef MACHO_PURE
4839: MACHOPIC_PURE
4840: #else
4841: flag_pic
4842: #endif
4843: )
4844: emit_jump_insn (gen_rtx (ADDR_DIFF_VEC, CASE_VECTOR_MODE,
4845: gen_rtx (LABEL_REF, Pmode, table_label),
4846: gen_rtvec_v (ncases, labelvec)));
4847: else
4848: emit_jump_insn (gen_rtx (ADDR_VEC, CASE_VECTOR_MODE,
4849: gen_rtvec_v (ncases, labelvec)));
4850:
4851: /* If the case insn drops through the table,
4852: after the table we must jump to the default-label.
4853: Otherwise record no drop-through after the table. */
4854: #ifdef CASE_DROPS_THROUGH
4855: emit_jump (default_label);
4856: #else
4857: emit_barrier ();
4858: #endif
4859: }
4860:
4861: before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
4862: reorder_insns (before_case, get_last_insn (),
4863: thiscase->data.case_stmt.start);
4864: }
4865: if (thiscase->exit_label)
4866: emit_label (thiscase->exit_label);
4867:
4868: POPSTACK (case_stack);
4869:
4870: free_temp_slots ();
4871: }
4872:
4873:
4874: /* Terminate a case statement. EXPR is the original index
4875: expression. */
4876: void
4877: bc_expand_end_case (expr)
4878: tree expr;
4879: {
4880: struct nesting *thiscase = case_stack;
4881: enum bytecode_opcode opcode;
4882: struct bc_label *jump_label;
4883: struct case_node *c;
4884:
4885: bc_emit_bytecode (jump);
4886: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
4887:
4888: #ifdef DEBUG_PRINT_CODE
4889: fputc ('\n', stderr);
4890: #endif
4891:
4892: /* Now that the size of the jump table is known, emit the actual
4893: indexed jump instruction. */
4894: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
4895:
4896: opcode = TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode
4897: ? TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseSU : caseSI
4898: : TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseDU : caseDI;
4899:
4900: bc_emit_bytecode (opcode);
4901:
4902: /* Now emit the case instructions literal arguments, in order.
4903: In addition to the value on the stack, it uses:
4904: 1. The address of the jump table.
4905: 2. The size of the jump table.
4906: 3. The default label. */
4907:
4908: jump_label = bc_get_bytecode_label ();
4909: bc_emit_bytecode_labelref (jump_label);
4910: bc_emit_bytecode_const ((char *) &thiscase->data.case_stmt.num_ranges,
4911: sizeof thiscase->data.case_stmt.num_ranges);
4912:
4913: if (thiscase->data.case_stmt.default_label)
4914: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (thiscase->data.case_stmt.default_label)));
4915: else
4916: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
4917:
4918: /* Output the jump table. */
4919:
4920: bc_align_bytecode (3 /* PTR_ALIGN */);
4921: bc_emit_bytecode_labeldef (jump_label);
4922:
4923: if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode)
4924: for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
4925: {
4926: opcode = TREE_INT_CST_LOW (c->low);
4927: bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
4928:
4929: opcode = TREE_INT_CST_LOW (c->high);
4930: bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
4931:
4932: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
4933: }
4934: else
4935: if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == DImode)
4936: for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
4937: {
4938: bc_emit_bytecode_DI_const (c->low);
4939: bc_emit_bytecode_DI_const (c->high);
4940:
4941: bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
4942: }
4943: else
4944: /* Bad mode */
4945: abort ();
4946:
4947:
4948: bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->exit_label));
4949:
4950: /* Possibly issue enumeration warnings. */
4951:
4952: if (!thiscase->data.case_stmt.default_label
4953: && TREE_CODE (TREE_TYPE (expr)) == ENUMERAL_TYPE
4954: && TREE_CODE (expr) != INTEGER_CST
4955: && warn_switch)
4956: check_for_full_enumeration_handling (TREE_TYPE (expr));
4957:
4958:
4959: #ifdef DEBUG_PRINT_CODE
4960: fputc ('\n', stderr);
4961: #endif
4962:
4963: POPSTACK (case_stack);
4964: }
4965:
4966:
4967: /* Return unique bytecode ID. */
4968: int
4969: bc_new_uid ()
4970: {
4971: static int bc_uid = 0;
4972:
4973: return (++bc_uid);
4974: }
4975:
4976: /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
4977:
4978: static void
4979: do_jump_if_equal (op1, op2, label, unsignedp)
4980: rtx op1, op2, label;
4981: int unsignedp;
4982: {
4983: if (GET_CODE (op1) == CONST_INT
4984: && GET_CODE (op2) == CONST_INT)
4985: {
4986: if (INTVAL (op1) == INTVAL (op2))
4987: emit_jump (label);
4988: }
4989: else
4990: {
4991: enum machine_mode mode = GET_MODE (op1);
4992: if (mode == VOIDmode)
4993: mode = GET_MODE (op2);
4994: emit_cmp_insn (op1, op2, EQ, NULL_RTX, mode, unsignedp, 0);
4995: emit_jump_insn (gen_beq (label));
4996: }
4997: }
4998:
4999: /* Not all case values are encountered equally. This function
5000: uses a heuristic to weight case labels, in cases where that
5001: looks like a reasonable thing to do.
5002:
5003: Right now, all we try to guess is text, and we establish the
5004: following weights:
5005:
5006: chars above space: 16
5007: digits: 16
5008: default: 12
5009: space, punct: 8
5010: tab: 4
5011: newline: 2
5012: other "\" chars: 1
5013: remaining chars: 0
5014:
5015: If we find any cases in the switch that are not either -1 or in the range
5016: of valid ASCII characters, or are control characters other than those
5017: commonly used with "\", don't treat this switch scanning text.
5018:
5019: Return 1 if these nodes are suitable for cost estimation, otherwise
5020: return 0. */
5021:
5022: static int
5023: estimate_case_costs (node)
5024: case_node_ptr node;
5025: {
5026: tree min_ascii = build_int_2 (-1, -1);
5027: tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5028: case_node_ptr n;
5029: int i;
5030:
5031: /* If we haven't already made the cost table, make it now. Note that the
5032: lower bound of the table is -1, not zero. */
5033:
5034: if (cost_table == NULL)
5035: {
5036: cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
5037: bzero (cost_table - 1, 129 * sizeof (short));
5038:
5039: for (i = 0; i < 128; i++)
5040: {
5041: if (isalnum (i))
5042: cost_table[i] = 16;
5043: else if (ispunct (i))
5044: cost_table[i] = 8;
5045: else if (iscntrl (i))
5046: cost_table[i] = -1;
5047: }
5048:
5049: cost_table[' '] = 8;
5050: cost_table['\t'] = 4;
5051: cost_table['\0'] = 4;
5052: cost_table['\n'] = 2;
5053: cost_table['\f'] = 1;
5054: cost_table['\v'] = 1;
5055: cost_table['\b'] = 1;
5056: }
5057:
5058: /* See if all the case expressions look like text. It is text if the
5059: constant is >= -1 and the highest constant is <= 127. Do all comparisons
5060: as signed arithmetic since we don't want to ever access cost_table with a
5061: value less than -1. Also check that none of the constants in a range
5062: are strange control characters. */
5063:
5064: for (n = node; n; n = n->right)
5065: {
5066: if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5067: return 0;
5068:
5069: for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
5070: if (cost_table[i] < 0)
5071: return 0;
5072: }
5073:
5074: /* All interesting values are within the range of interesting
5075: ASCII characters. */
5076: return 1;
5077: }
5078:
5079: /* Scan an ordered list of case nodes
5080: combining those with consecutive values or ranges.
5081:
5082: Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5083:
5084: static void
5085: group_case_nodes (head)
5086: case_node_ptr head;
5087: {
5088: case_node_ptr node = head;
5089:
5090: while (node)
5091: {
5092: rtx lb = next_real_insn (label_rtx (node->code_label));
5093: case_node_ptr np = node;
5094:
5095: /* Try to group the successors of NODE with NODE. */
5096: while (((np = np->right) != 0)
5097: /* Do they jump to the same place? */
5098: && next_real_insn (label_rtx (np->code_label)) == lb
5099: /* Are their ranges consecutive? */
5100: && tree_int_cst_equal (np->low,
5101: fold (build (PLUS_EXPR,
5102: TREE_TYPE (node->high),
5103: node->high,
5104: integer_one_node)))
5105: /* An overflow is not consecutive. */
5106: && tree_int_cst_lt (node->high,
5107: fold (build (PLUS_EXPR,
5108: TREE_TYPE (node->high),
5109: node->high,
5110: integer_one_node))))
5111: {
5112: node->high = np->high;
5113: }
5114: /* NP is the first node after NODE which can't be grouped with it.
5115: Delete the nodes in between, and move on to that node. */
5116: node->right = np;
5117: node = np;
5118: }
5119: }
5120:
5121: /* Take an ordered list of case nodes
5122: and transform them into a near optimal binary tree,
5123: on the assumption that any target code selection value is as
5124: likely as any other.
5125:
5126: The transformation is performed by splitting the ordered
5127: list into two equal sections plus a pivot. The parts are
5128: then attached to the pivot as left and right branches. Each
5129: branch is is then transformed recursively. */
5130:
5131: static void
5132: balance_case_nodes (head, parent)
5133: case_node_ptr *head;
5134: case_node_ptr parent;
5135: {
5136: register case_node_ptr np;
5137:
5138: np = *head;
5139: if (np)
5140: {
5141: int cost = 0;
5142: int i = 0;
5143: int ranges = 0;
5144: register case_node_ptr *npp;
5145: case_node_ptr left;
5146:
5147: /* Count the number of entries on branch. Also count the ranges. */
5148:
5149: while (np)
5150: {
5151: if (!tree_int_cst_equal (np->low, np->high))
5152: {
5153: ranges++;
5154: if (use_cost_table)
5155: cost += cost_table[TREE_INT_CST_LOW (np->high)];
5156: }
5157:
5158: if (use_cost_table)
5159: cost += cost_table[TREE_INT_CST_LOW (np->low)];
5160:
5161: i++;
5162: np = np->right;
5163: }
5164:
5165: if (i > 2)
5166: {
5167: /* Split this list if it is long enough for that to help. */
5168: npp = head;
5169: left = *npp;
5170: if (use_cost_table)
5171: {
5172: /* Find the place in the list that bisects the list's total cost,
5173: Here I gets half the total cost. */
5174: int n_moved = 0;
5175: i = (cost + 1) / 2;
5176: while (1)
5177: {
5178: /* Skip nodes while their cost does not reach that amount. */
5179: if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5180: i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5181: i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5182: if (i <= 0)
5183: break;
5184: npp = &(*npp)->right;
5185: n_moved += 1;
5186: }
5187: if (n_moved == 0)
5188: {
5189: /* Leave this branch lopsided, but optimize left-hand
5190: side and fill in `parent' fields for right-hand side. */
5191: np = *head;
5192: np->parent = parent;
5193: balance_case_nodes (&np->left, np);
5194: for (; np->right; np = np->right)
5195: np->right->parent = np;
5196: return;
5197: }
5198: }
5199: /* If there are just three nodes, split at the middle one. */
5200: else if (i == 3)
5201: npp = &(*npp)->right;
5202: else
5203: {
5204: /* Find the place in the list that bisects the list's total cost,
5205: where ranges count as 2.
5206: Here I gets half the total cost. */
5207: i = (i + ranges + 1) / 2;
5208: while (1)
5209: {
5210: /* Skip nodes while their cost does not reach that amount. */
5211: if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5212: i--;
5213: i--;
5214: if (i <= 0)
5215: break;
5216: npp = &(*npp)->right;
5217: }
5218: }
5219: *head = np = *npp;
5220: *npp = 0;
5221: np->parent = parent;
5222: np->left = left;
5223:
5224: /* Optimize each of the two split parts. */
5225: balance_case_nodes (&np->left, np);
5226: balance_case_nodes (&np->right, np);
5227: }
5228: else
5229: {
5230: /* Else leave this branch as one level,
5231: but fill in `parent' fields. */
5232: np = *head;
5233: np->parent = parent;
5234: for (; np->right; np = np->right)
5235: np->right->parent = np;
5236: }
5237: }
5238: }
5239:
5240: /* Search the parent sections of the case node tree
5241: to see if a test for the lower bound of NODE would be redundant.
5242: INDEX_TYPE is the type of the index expression.
5243:
5244: The instructions to generate the case decision tree are
5245: output in the same order as nodes are processed so it is
5246: known that if a parent node checks the range of the current
5247: node minus one that the current node is bounded at its lower
5248: span. Thus the test would be redundant. */
5249:
5250: static int
5251: node_has_low_bound (node, index_type)
5252: case_node_ptr node;
5253: tree index_type;
5254: {
5255: tree low_minus_one;
5256: case_node_ptr pnode;
5257:
5258: /* If the lower bound of this node is the lowest value in the index type,
5259: we need not test it. */
5260:
5261: if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5262: return 1;
5263:
5264: /* If this node has a left branch, the value at the left must be less
5265: than that at this node, so it cannot be bounded at the bottom and
5266: we need not bother testing any further. */
5267:
5268: if (node->left)
5269: return 0;
5270:
5271: low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5272: node->low, integer_one_node));
5273:
5274: /* If the subtraction above overflowed, we can't verify anything.
5275: Otherwise, look for a parent that tests our value - 1. */
5276:
5277: if (! tree_int_cst_lt (low_minus_one, node->low))
5278: return 0;
5279:
5280: for (pnode = node->parent; pnode; pnode = pnode->parent)
5281: if (tree_int_cst_equal (low_minus_one, pnode->high))
5282: return 1;
5283:
5284: return 0;
5285: }
5286:
5287: /* Search the parent sections of the case node tree
5288: to see if a test for the upper bound of NODE would be redundant.
5289: INDEX_TYPE is the type of the index expression.
5290:
5291: The instructions to generate the case decision tree are
5292: output in the same order as nodes are processed so it is
5293: known that if a parent node checks the range of the current
5294: node plus one that the current node is bounded at its upper
5295: span. Thus the test would be redundant. */
5296:
5297: static int
5298: node_has_high_bound (node, index_type)
5299: case_node_ptr node;
5300: tree index_type;
5301: {
5302: tree high_plus_one;
5303: case_node_ptr pnode;
5304:
5305: /* If the upper bound of this node is the highest value in the type
5306: of the index expression, we need not test against it. */
5307:
5308: if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5309: return 1;
5310:
5311: /* If this node has a right branch, the value at the right must be greater
5312: than that at this node, so it cannot be bounded at the top and
5313: we need not bother testing any further. */
5314:
5315: if (node->right)
5316: return 0;
5317:
5318: high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5319: node->high, integer_one_node));
5320:
5321: /* If the addition above overflowed, we can't verify anything.
5322: Otherwise, look for a parent that tests our value + 1. */
5323:
5324: if (! tree_int_cst_lt (node->high, high_plus_one))
5325: return 0;
5326:
5327: for (pnode = node->parent; pnode; pnode = pnode->parent)
5328: if (tree_int_cst_equal (high_plus_one, pnode->low))
5329: return 1;
5330:
5331: return 0;
5332: }
5333:
5334: /* Search the parent sections of the
5335: case node tree to see if both tests for the upper and lower
5336: bounds of NODE would be redundant. */
5337:
5338: static int
5339: node_is_bounded (node, index_type)
5340: case_node_ptr node;
5341: tree index_type;
5342: {
5343: return (node_has_low_bound (node, index_type)
5344: && node_has_high_bound (node, index_type));
5345: }
5346:
5347: /* Emit an unconditional jump to LABEL unless it would be dead code. */
5348:
5349: static void
5350: emit_jump_if_reachable (label)
5351: rtx label;
5352: {
5353: if (GET_CODE (get_last_insn ()) != BARRIER)
5354: emit_jump (label);
5355: }
5356:
5357: /* Emit step-by-step code to select a case for the value of INDEX.
5358: The thus generated decision tree follows the form of the
5359: case-node binary tree NODE, whose nodes represent test conditions.
5360: INDEX_TYPE is the type of the index of the switch.
5361:
5362: Care is taken to prune redundant tests from the decision tree
5363: by detecting any boundary conditions already checked by
5364: emitted rtx. (See node_has_high_bound, node_has_low_bound
5365: and node_is_bounded, above.)
5366:
5367: Where the test conditions can be shown to be redundant we emit
5368: an unconditional jump to the target code. As a further
5369: optimization, the subordinates of a tree node are examined to
5370: check for bounded nodes. In this case conditional and/or
5371: unconditional jumps as a result of the boundary check for the
5372: current node are arranged to target the subordinates associated
5373: code for out of bound conditions on the current node node.
5374:
5375: We can assume that when control reaches the code generated here,
5376: the index value has already been compared with the parents
5377: of this node, and determined to be on the same side of each parent
5378: as this node is. Thus, if this node tests for the value 51,
5379: and a parent tested for 52, we don't need to consider
5380: the possibility of a value greater than 51. If another parent
5381: tests for the value 50, then this node need not test anything. */
5382:
5383: static void
5384: emit_case_nodes (index, node, default_label, index_type)
5385: rtx index;
5386: case_node_ptr node;
5387: rtx default_label;
5388: tree index_type;
5389: {
5390: /* If INDEX has an unsigned type, we must make unsigned branches. */
5391: int unsignedp = TREE_UNSIGNED (index_type);
5392: typedef rtx rtx_function ();
5393: rtx_function *gen_bgt_pat = unsignedp ? gen_bgtu : gen_bgt;
5394: rtx_function *gen_bge_pat = unsignedp ? gen_bgeu : gen_bge;
5395: rtx_function *gen_blt_pat = unsignedp ? gen_bltu : gen_blt;
5396: rtx_function *gen_ble_pat = unsignedp ? gen_bleu : gen_ble;
5397: enum machine_mode mode = GET_MODE (index);
5398:
5399: /* See if our parents have already tested everything for us.
5400: If they have, emit an unconditional jump for this node. */
5401: if (node_is_bounded (node, index_type))
5402: emit_jump (label_rtx (node->code_label));
5403:
5404: else if (tree_int_cst_equal (node->low, node->high))
5405: {
5406: /* Node is single valued. First see if the index expression matches
5407: this node and then check our children, if any. */
5408:
5409: do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5410: label_rtx (node->code_label), unsignedp);
5411:
5412: if (node->right != 0 && node->left != 0)
5413: {
5414: /* This node has children on both sides.
5415: Dispatch to one side or the other
5416: by comparing the index value with this node's value.
5417: If one subtree is bounded, check that one first,
5418: so we can avoid real branches in the tree. */
5419:
5420: if (node_is_bounded (node->right, index_type))
5421: {
5422: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5423: VOIDmode, 0),
5424: GT, NULL_RTX, mode, unsignedp, 0);
5425:
5426: emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5427: emit_case_nodes (index, node->left, default_label, index_type);
5428: }
5429:
5430: else if (node_is_bounded (node->left, index_type))
5431: {
5432: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5433: VOIDmode, 0),
5434: LT, NULL_RTX, mode, unsignedp, 0);
5435: emit_jump_insn ((*gen_blt_pat) (label_rtx (node->left->code_label)));
5436: emit_case_nodes (index, node->right, default_label, index_type);
5437: }
5438:
5439: else
5440: {
5441: /* Neither node is bounded. First distinguish the two sides;
5442: then emit the code for one side at a time. */
5443:
5444: tree test_label
5445: = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5446:
5447: /* See if the value is on the right. */
5448: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5449: VOIDmode, 0),
5450: GT, NULL_RTX, mode, unsignedp, 0);
5451: emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5452:
5453: /* Value must be on the left.
5454: Handle the left-hand subtree. */
5455: emit_case_nodes (index, node->left, default_label, index_type);
5456: /* If left-hand subtree does nothing,
5457: go to default. */
5458: emit_jump_if_reachable (default_label);
5459:
5460: /* Code branches here for the right-hand subtree. */
5461: expand_label (test_label);
5462: emit_case_nodes (index, node->right, default_label, index_type);
5463: }
5464: }
5465:
5466: else if (node->right != 0 && node->left == 0)
5467: {
5468: /* Here we have a right child but no left so we issue conditional
5469: branch to default and process the right child.
5470:
5471: Omit the conditional branch to default if we it avoid only one
5472: right child; it costs too much space to save so little time. */
5473:
5474: if (node->right->right || node->right->left
5475: || !tree_int_cst_equal (node->right->low, node->right->high))
5476: {
5477: if (!node_has_low_bound (node, index_type))
5478: {
5479: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5480: VOIDmode, 0),
5481: LT, NULL_RTX, mode, unsignedp, 0);
5482: emit_jump_insn ((*gen_blt_pat) (default_label));
5483: }
5484:
5485: emit_case_nodes (index, node->right, default_label, index_type);
5486: }
5487: else
5488: /* We cannot process node->right normally
5489: since we haven't ruled out the numbers less than
5490: this node's value. So handle node->right explicitly. */
5491: do_jump_if_equal (index,
5492: expand_expr (node->right->low, NULL_RTX,
5493: VOIDmode, 0),
5494: label_rtx (node->right->code_label), unsignedp);
5495: }
5496:
5497: else if (node->right == 0 && node->left != 0)
5498: {
5499: /* Just one subtree, on the left. */
5500:
5501: #if 0 /* The following code and comment were formerly part
5502: of the condition here, but they didn't work
5503: and I don't understand what the idea was. -- rms. */
5504: /* If our "most probable entry" is less probable
5505: than the default label, emit a jump to
5506: the default label using condition codes
5507: already lying around. With no right branch,
5508: a branch-greater-than will get us to the default
5509: label correctly. */
5510: if (use_cost_table
5511: && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
5512: ;
5513: #endif /* 0 */
5514: if (node->left->left || node->left->right
5515: || !tree_int_cst_equal (node->left->low, node->left->high))
5516: {
5517: if (!node_has_high_bound (node, index_type))
5518: {
5519: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5520: VOIDmode, 0),
5521: GT, NULL_RTX, mode, unsignedp, 0);
5522: emit_jump_insn ((*gen_bgt_pat) (default_label));
5523: }
5524:
5525: emit_case_nodes (index, node->left, default_label, index_type);
5526: }
5527: else
5528: /* We cannot process node->left normally
5529: since we haven't ruled out the numbers less than
5530: this node's value. So handle node->left explicitly. */
5531: do_jump_if_equal (index,
5532: expand_expr (node->left->low, NULL_RTX,
5533: VOIDmode, 0),
5534: label_rtx (node->left->code_label), unsignedp);
5535: }
5536: }
5537: else
5538: {
5539: /* Node is a range. These cases are very similar to those for a single
5540: value, except that we do not start by testing whether this node
5541: is the one to branch to. */
5542:
5543: if (node->right != 0 && node->left != 0)
5544: {
5545: /* Node has subtrees on both sides.
5546: If the right-hand subtree is bounded,
5547: test for it first, since we can go straight there.
5548: Otherwise, we need to make a branch in the control structure,
5549: then handle the two subtrees. */
5550: tree test_label = 0;
5551:
5552: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5553: VOIDmode, 0),
5554: GT, NULL_RTX, mode, unsignedp, 0);
5555:
5556: if (node_is_bounded (node->right, index_type))
5557: /* Right hand node is fully bounded so we can eliminate any
5558: testing and branch directly to the target code. */
5559: emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5560: else
5561: {
5562: /* Right hand node requires testing.
5563: Branch to a label where we will handle it later. */
5564:
5565: test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5566: emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5567: }
5568:
5569: /* Value belongs to this node or to the left-hand subtree. */
5570:
5571: emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5572: GE, NULL_RTX, mode, unsignedp, 0);
5573: emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5574:
5575: /* Handle the left-hand subtree. */
5576: emit_case_nodes (index, node->left, default_label, index_type);
5577:
5578: /* If right node had to be handled later, do that now. */
5579:
5580: if (test_label)
5581: {
5582: /* If the left-hand subtree fell through,
5583: don't let it fall into the right-hand subtree. */
5584: emit_jump_if_reachable (default_label);
5585:
5586: expand_label (test_label);
5587: emit_case_nodes (index, node->right, default_label, index_type);
5588: }
5589: }
5590:
5591: else if (node->right != 0 && node->left == 0)
5592: {
5593: /* Deal with values to the left of this node,
5594: if they are possible. */
5595: if (!node_has_low_bound (node, index_type))
5596: {
5597: emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5598: VOIDmode, 0),
5599: LT, NULL_RTX, mode, unsignedp, 0);
5600: emit_jump_insn ((*gen_blt_pat) (default_label));
5601: }
5602:
5603: /* Value belongs to this node or to the right-hand subtree. */
5604:
5605: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5606: VOIDmode, 0),
5607: LE, NULL_RTX, mode, unsignedp, 0);
5608: emit_jump_insn ((*gen_ble_pat) (label_rtx (node->code_label)));
5609:
5610: emit_case_nodes (index, node->right, default_label, index_type);
5611: }
5612:
5613: else if (node->right == 0 && node->left != 0)
5614: {
5615: /* Deal with values to the right of this node,
5616: if they are possible. */
5617: if (!node_has_high_bound (node, index_type))
5618: {
5619: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5620: VOIDmode, 0),
5621: GT, NULL_RTX, mode, unsignedp, 0);
5622: emit_jump_insn ((*gen_bgt_pat) (default_label));
5623: }
5624:
5625: /* Value belongs to this node or to the left-hand subtree. */
5626:
5627: emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5628: GE, NULL_RTX, mode, unsignedp, 0);
5629: emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5630:
5631: emit_case_nodes (index, node->left, default_label, index_type);
5632: }
5633:
5634: else
5635: {
5636: /* Node has no children so we check low and high bounds to remove
5637: redundant tests. Only one of the bounds can exist,
5638: since otherwise this node is bounded--a case tested already. */
5639:
5640: if (!node_has_high_bound (node, index_type))
5641: {
5642: emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5643: VOIDmode, 0),
5644: GT, NULL_RTX, mode, unsignedp, 0);
5645: emit_jump_insn ((*gen_bgt_pat) (default_label));
5646: }
5647:
5648: if (!node_has_low_bound (node, index_type))
5649: {
5650: emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5651: VOIDmode, 0),
5652: LT, NULL_RTX, mode, unsignedp, 0);
5653: emit_jump_insn ((*gen_blt_pat) (default_label));
5654: }
5655:
5656: emit_jump (label_rtx (node->code_label));
5657: }
5658: }
5659: }
5660:
5661: /* These routines are used by the loop unrolling code. They copy BLOCK trees
5662: so that the debugging info will be correct for the unrolled loop. */
5663:
5664: /* Indexed by block number, contains a pointer to the N'th block node. */
5665:
5666: static tree *block_vector;
5667:
5668: void
5669: find_loop_tree_blocks ()
5670: {
5671: tree block = DECL_INITIAL (current_function_decl);
5672:
5673: /* There first block is for the function body, and does not have
5674: corresponding block notes. Don't include it in the block vector. */
5675: block = BLOCK_SUBBLOCKS (block);
5676:
5677: block_vector = identify_blocks (block, get_insns ());
5678: }
5679:
5680: void
5681: unroll_block_trees ()
5682: {
5683: tree block = DECL_INITIAL (current_function_decl);
5684:
5685: reorder_blocks (block_vector, block, get_insns ());
5686: }
5687:
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