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1.1 root 1: /* Garbage collection primitives for GNU C++.
2: Copyright (C) 1992, 1993 Free Software Foundation, Inc.
3: Contributed by Michael Tiemann ([email protected])
4:
5: This file is part of GNU CC.
6:
7: GNU CC is free software; you can redistribute it and/or modify
8: it under the terms of the GNU General Public License as published by
9: the Free Software Foundation; either version 2, or (at your option)
10: any later version.
11:
12: GNU CC is distributed in the hope that it will be useful,
13: but WITHOUT ANY WARRANTY; without even the implied warranty of
14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: GNU General Public License for more details.
16:
17: You should have received a copy of the GNU General Public License
18: along with GNU CC; see the file COPYING. If not, write to
19: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
20:
21:
22: #include "config.h"
23: #include "tree.h"
24: #include "cp-tree.h"
25: #include "flags.h"
26:
27: #undef NULL
28: #define NULL 0
29:
30: extern tree define_function ();
31: extern tree build_t_desc_overload ();
32:
33: /* This is the function decl for the (pseudo-builtin) __gc_protect
34: function. Args are (class *value, int index); Returns value. */
35: tree gc_protect_fndecl;
36:
37: /* This is the function decl for the (pseudo-builtin) __gc_unprotect
38: function. Args are (int index); void return. */
39: tree gc_unprotect_fndecl;
40:
41: /* This is the function decl for the (pseudo-builtin) __gc_push
42: function. Args are (int length); void return. */
43: tree gc_push_fndecl;
44:
45: /* This is the function decl for the (pseudo-builtin) __gc_pop
46: function. Args are void; void return. */
47: tree gc_pop_fndecl;
48:
49: /* Special integers that are used to represent bits in gc-safe objects. */
50: tree gc_nonobject;
51: tree gc_visible;
52: tree gc_white;
53: tree gc_offwhite;
54: tree gc_grey;
55: tree gc_black;
56:
57: /* in c-common.c */
58: extern tree combine_strings PROTO((tree));
59:
60: /* Predicate that returns non-zero if TYPE needs some kind of
61: entry for the GC. Returns zero otherwise. */
62: int
63: type_needs_gc_entry (type)
64: tree type;
65: {
66: tree ttype = type;
67:
68: if (! flag_gc || type == error_mark_node)
69: return 0;
70:
71: /* Aggregate types need gc entries if any of their members
72: need gc entries. */
73: if (IS_AGGR_TYPE (type))
74: {
75: tree binfos;
76: tree fields = TYPE_FIELDS (type);
77: int i;
78:
79: /* We don't care about certain pointers. Pointers
80: to virtual baseclasses are always up front. We also
81: cull out virtual function table pointers because it's
82: easy, and it simplifies the logic.*/
83: while (fields
84: && (DECL_NAME (fields) == NULL_TREE
85: || VFIELD_NAME_P (DECL_NAME (fields))
86: || VBASE_NAME_P (DECL_NAME (fields))
87: || !strcmp (IDENTIFIER_POINTER (DECL_NAME (fields)), "__bits")))
88: fields = TREE_CHAIN (fields);
89:
90: while (fields)
91: {
92: if (type_needs_gc_entry (TREE_TYPE (fields)))
93: return 1;
94: fields = TREE_CHAIN (fields);
95: }
96:
97: binfos = TYPE_BINFO_BASETYPES (type);
98: if (binfos)
99: for (i = TREE_VEC_LENGTH (binfos)-1; i >= 0; i--)
100: if (type_needs_gc_entry (BINFO_TYPE (TREE_VEC_ELT (binfos, i))))
101: return 1;
102:
103: return 0;
104: }
105:
106: while (TREE_CODE (ttype) == ARRAY_TYPE
107: && TREE_CODE (TREE_TYPE (ttype)) == ARRAY_TYPE)
108: ttype = TREE_TYPE (ttype);
109: if ((TREE_CODE (ttype) == POINTER_TYPE
110: || TREE_CODE (ttype) == ARRAY_TYPE
111: || TREE_CODE (ttype) == REFERENCE_TYPE)
112: && IS_AGGR_TYPE (TREE_TYPE (ttype))
113: && CLASSTYPE_DOSSIER (TREE_TYPE (ttype)))
114: return 1;
115:
116: return 0;
117: }
118:
119: /* Predicate that returns non-zero iff FROM is safe from the GC.
120:
121: If TO is nonzero, it means we know that FROM is being stored
122: in TO, which make make it safe. */
123: int
124: value_safe_from_gc (to, from)
125: tree to, from;
126: {
127: /* First, return non-zero for easy cases: parameters,
128: static variables. */
129: if (TREE_CODE (from) == PARM_DECL
130: || (TREE_CODE (from) == VAR_DECL
131: && TREE_STATIC (from)))
132: return 1;
133:
134: /* If something has its address taken, it cannot be
135: in the heap, so it doesn't need to be protected. */
136: if (TREE_CODE (from) == ADDR_EXPR || TREE_REFERENCE_EXPR (from))
137: return 1;
138:
139: /* If we are storing into a static variable, then what
140: we store will be safe from the gc. */
141: if (to && TREE_CODE (to) == VAR_DECL
142: && TREE_STATIC (to))
143: return 1;
144:
145: /* Now recurse on structure of FROM. */
146: switch (TREE_CODE (from))
147: {
148: case COMPONENT_REF:
149: /* These guys are special, and safe. */
150: if (TREE_CODE (TREE_OPERAND (from, 1)) == FIELD_DECL
151: && (VFIELD_NAME_P (DECL_NAME (TREE_OPERAND (from, 1)))
152: || VBASE_NAME_P (DECL_NAME (TREE_OPERAND (from, 1)))))
153: return 1;
154: /* fall through... */
155: case NOP_EXPR:
156: case CONVERT_EXPR:
157: case NON_LVALUE_EXPR:
158: case WITH_CLEANUP_EXPR:
159: case SAVE_EXPR:
160: case PREDECREMENT_EXPR:
161: case PREINCREMENT_EXPR:
162: case POSTDECREMENT_EXPR:
163: case POSTINCREMENT_EXPR:
164: if (value_safe_from_gc (to, TREE_OPERAND (from, 0)))
165: return 1;
166: break;
167:
168: case VAR_DECL:
169: case PARM_DECL:
170: /* We can safely pass these things as parameters to functions. */
171: if (to == 0)
172: return 1;
173:
174: case ARRAY_REF:
175: case INDIRECT_REF:
176: case RESULT_DECL:
177: case OFFSET_REF:
178: case CALL_EXPR:
179: case METHOD_CALL_EXPR:
180: break;
181:
182: case COMPOUND_EXPR:
183: case TARGET_EXPR:
184: if (value_safe_from_gc (to, TREE_OPERAND (from, 1)))
185: return 1;
186: break;
187:
188: case COND_EXPR:
189: if (value_safe_from_gc (to, TREE_OPERAND (from, 1))
190: && value_safe_from_gc (to, TREE_OPERAND (from, 2)))
191: return 1;
192: break;
193:
194: case PLUS_EXPR:
195: case MINUS_EXPR:
196: if ((type_needs_gc_entry (TREE_TYPE (TREE_OPERAND (from, 0)))
197: || value_safe_from_gc (to, TREE_OPERAND (from, 0)))
198: && (type_needs_gc_entry (TREE_TYPE (TREE_OPERAND (from, 1))) == 0
199: || value_safe_from_gc (to, TREE_OPERAND (from, 1))))
200: return 1;
201: break;
202:
203: case RTL_EXPR:
204: /* Every time we build an RTL_EXPR in the front-end, we must
205: ensure that everything in it is safe from the garbage collector.
206: ??? This has only been done for `build_new'. */
207: return 1;
208:
209: default:
210: my_friendly_abort (41);
211: }
212:
213: if (to == 0)
214: return 0;
215:
216: /* FROM wasn't safe. But other properties of TO might make it safe. */
217: switch (TREE_CODE (to))
218: {
219: case VAR_DECL:
220: case PARM_DECL:
221: /* We already culled out static VAR_DECLs above. */
222: return 0;
223:
224: case COMPONENT_REF:
225: /* These guys are special, and safe. */
226: if (TREE_CODE (TREE_OPERAND (to, 1)) == FIELD_DECL
227: && (VFIELD_NAME_P (DECL_NAME (TREE_OPERAND (to, 1)))
228: || VBASE_NAME_P (DECL_NAME (TREE_OPERAND (to, 1)))))
229: return 1;
230: /* fall through... */
231:
232: case NOP_EXPR:
233: case NON_LVALUE_EXPR:
234: case WITH_CLEANUP_EXPR:
235: case SAVE_EXPR:
236: case PREDECREMENT_EXPR:
237: case PREINCREMENT_EXPR:
238: case POSTDECREMENT_EXPR:
239: case POSTINCREMENT_EXPR:
240: return value_safe_from_gc (TREE_OPERAND (to, 0), from);
241:
242: case COMPOUND_EXPR:
243: case TARGET_EXPR:
244: return value_safe_from_gc (TREE_OPERAND (to, 1), from);
245:
246: case COND_EXPR:
247: return (value_safe_from_gc (TREE_OPERAND (to, 1), from)
248: && value_safe_from_gc (TREE_OPERAND (to, 2), from));
249:
250: case INDIRECT_REF:
251: case ARRAY_REF:
252: /* This used to be 0, but our current restricted model
253: allows this to be 1. We'll never get arrays this way. */
254: return 1;
255:
256: default:
257: my_friendly_abort (42);
258: }
259:
260: /* Catch-all case is that TO/FROM is not safe. */
261: return 0;
262: }
263:
264: /* Function to build a static GC entry for DECL. TYPE is DECL's type.
265:
266: For objects of type `class *', this is just an entry in the
267: static vector __PTR_LIST__.
268:
269: For objects of type `class[]', this requires building an entry
270: in the static vector __ARR_LIST__.
271:
272: For aggregates, this records all fields of type `class *'
273: and `class[]' in the respective lists above. */
274: void
275: build_static_gc_entry (decl, type)
276: tree decl;
277: tree type;
278: {
279: /* Now, figure out what sort of entry to build. */
280: if (TREE_CODE (type) == POINTER_TYPE
281: || TREE_CODE (type) == REFERENCE_TYPE)
282: assemble_gc_entry (IDENTIFIER_POINTER (DECL_NAME (decl)));
283: else if (TREE_CODE (type) == RECORD_TYPE)
284: {
285: tree ref = get_temp_name (build_reference_type (type), 1);
286: DECL_INITIAL (ref) = build1 (ADDR_EXPR, TREE_TYPE (ref), decl);
287: TREE_CONSTANT (DECL_INITIAL (ref)) = 1;
288: finish_decl (ref, DECL_INITIAL (ref), 0, 0);
289: }
290: else
291: {
292: /* Not yet implemented.
293:
294: Cons up a static variable that holds address and length info
295: and add that to ___ARR_LIST__. */
296: my_friendly_abort (43);
297: }
298: }
299:
300: /* Protect FROM from the GC, assuming FROM is going to be
301: stored into TO. We handle three cases for TO here:
302:
303: case 1: TO is a stack variable.
304: case 2: TO is zero (which means it is a parameter).
305: case 3: TO is a return value. */
306:
307: tree
308: protect_value_from_gc (to, from)
309: tree to, from;
310: {
311: if (to == 0)
312: {
313: tree cleanup;
314:
315: to = get_temp_regvar (TREE_TYPE (from), from);
316:
317: /* Convert from integer to list form since we'll use it twice. */
318: DECL_GC_OFFSET (to) = build_tree_list (NULL_TREE, DECL_GC_OFFSET (to));
319: cleanup = build_function_call (gc_unprotect_fndecl,
320: DECL_GC_OFFSET (to));
321:
322: if (! expand_decl_cleanup (to, cleanup))
323: {
324: compiler_error ("cannot unprotect parameter in this scope");
325: return error_mark_node;
326: }
327: }
328:
329: /* Should never need to protect a value that's headed for static storage. */
330: if (TREE_STATIC (to))
331: my_friendly_abort (44);
332:
333: switch (TREE_CODE (to))
334: {
335: case COMPONENT_REF:
336: case INDIRECT_REF:
337: return protect_value_from_gc (TREE_OPERAND (to, 0), from);
338:
339: case VAR_DECL:
340: case PARM_DECL:
341: {
342: tree rval;
343: if (DECL_GC_OFFSET (to) == NULL_TREE)
344: {
345: /* Because of a cast or a conversion, we might stick
346: a value into a variable that would not normally
347: have a GC entry. */
348: DECL_GC_OFFSET (to) = size_int (++current_function_obstack_index);
349: }
350:
351: if (TREE_CODE (DECL_GC_OFFSET (to)) != TREE_LIST)
352: {
353: DECL_GC_OFFSET (to)
354: = build_tree_list (NULL_TREE, DECL_GC_OFFSET (to));
355: }
356:
357: current_function_obstack_usage = 1;
358: rval = build_function_call (gc_protect_fndecl,
359: tree_cons (NULL_TREE, from,
360: DECL_GC_OFFSET (to)));
361: TREE_TYPE (rval) = TREE_TYPE (from);
362: return rval;
363: }
364: }
365:
366: /* If we fall through the switch, assume we lost. */
367: my_friendly_abort (45);
368: /* NOTREACHED */
369: return NULL_TREE;
370: }
371:
372: /* Given the expression EXP of type `class *', return the head
373: of the object pointed to by EXP. */
374: tree
375: build_headof (exp)
376: tree exp;
377: {
378: tree type = TREE_TYPE (exp);
379: tree vptr, offset;
380:
381: if (TREE_CODE (type) != POINTER_TYPE)
382: {
383: error ("`headof' applied to non-pointer type");
384: return error_mark_node;
385: }
386:
387: vptr = build1 (INDIRECT_REF, TYPE_POINTER_TO (vtable_entry_type), exp);
388: offset = build_component_ref (build_array_ref (vptr, integer_one_node),
389: get_identifier (VTABLE_DELTA_NAME),
390: NULL_TREE, 0);
391: return build (PLUS_EXPR, class_star_type_node, exp,
392: convert (integer_type_node, offset));
393: }
394:
395: /* Given the expression EXP of type `class *', return the
396: type descriptor for the object pointed to by EXP. */
397: tree
398: build_classof (exp)
399: tree exp;
400: {
401: tree type = TREE_TYPE (exp);
402: tree vptr;
403: tree t_desc_entry;
404:
405: if (TREE_CODE (type) != POINTER_TYPE)
406: {
407: error ("`classof' applied to non-pointer type");
408: return error_mark_node;
409: }
410:
411: vptr = build1 (INDIRECT_REF, TYPE_POINTER_TO (vtable_entry_type), exp);
412: t_desc_entry = build_component_ref (build_array_ref (vptr, integer_one_node),
413: get_identifier (VTABLE_PFN_NAME),
414: NULL_TREE, 0);
415: TREE_TYPE (t_desc_entry) = TYPE_POINTER_TO (__t_desc_type_node);
416: return t_desc_entry;
417: }
418:
419: /* Return the Type_info node associated with the expression EXP. If EXP is
420: a reference to a polymorphic class, return the dynamic type; otherwise
421: return the static type of the expression. */
422: tree
423: build_typeid (exp)
424: tree exp;
425: {
426: tree type;
427:
428: if (exp == error_mark_node)
429: return error_mark_node;
430:
431: type = TREE_TYPE (exp);
432:
433: /* if b is an instance of B, typeid(b) == typeid(B). Do this before
434: reference trickiness. */
435: if (TREE_CODE (exp) == VAR_DECL && TREE_CODE (type) == RECORD_TYPE)
436: return get_typeid (type);
437:
438: /* Apply trivial conversion T -> T& for dereferenced ptrs. */
439: if (TREE_CODE (type) == RECORD_TYPE)
440: type = build_reference_type (type);
441:
442: /* If exp is a reference to polymorphic type, get the real Type_info. */
443: if (TREE_CODE (type) == REFERENCE_TYPE && TYPE_VIRTUAL_P (TREE_TYPE (type)))
444: {
445: /* build reference to Type_info from vtable. */
446:
447: sorry ("finding Type_info for an object");
448: return error_mark_node;
449: }
450:
451: /* otherwise return the Type_info for the static type of the expr. */
452: return get_typeid (type);
453: }
454:
455: /* Return the Type_info object for TYPE, creating it if necessary. */
456: tree
457: get_typeid (type)
458: tree type;
459: {
460: if (type == error_mark_node)
461: return error_mark_node;
462:
463: /* Is it useful (and/or correct) to have different typeids for `T &'
464: and `T'? */
465: if (TREE_CODE (type) == REFERENCE_TYPE)
466: type = TREE_TYPE (type);
467:
468: /* build reference to static Type_info */
469: #if 1
470: sorry ("finding Type_info for a type");
471: return error_mark_node;
472: #else
473: register tree t = TYPE_TINFO (type);
474:
475: if (t)
476: return t;
477:
478: /* ... */
479:
480: #endif
481: }
482:
483: /* Execute a dynamic cast, as described in section 5.2.6 of the 9/93 working
484: paper. */
485: tree
486: build_dynamic_cast (type, expr)
487: tree type, expr;
488: {
489: enum tree_code tc = TREE_CODE (type);
490: tree exprtype = TREE_TYPE (expr);
491: enum tree_code ec = TREE_CODE (exprtype);
492: tree retval;
493:
494: if (type == error_mark_node || expr == error_mark_node)
495: return error_mark_node;
496:
497: switch (tc)
498: {
499: case POINTER_TYPE:
500: if (TREE_TYPE (type) == void_type_node)
501: break;
502: /* else fall through */
503: case REFERENCE_TYPE:
504: if (TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
505: && TYPE_SIZE (TREE_TYPE (type)) != NULL_TREE)
506: break;
507: /* else fall through */
508: default:
509: cp_error ("`%#T' is not a valid type argument for dynamic_cast", type);
510: error ("(must be either pointer or reference to defined class or void *)");
511: return error_mark_node;
512: }
513:
514: /* Apply trivial conversion T -> T& for dereferenced ptrs. */
515: if (ec == RECORD_TYPE)
516: {
517: exprtype = build_reference_type (exprtype);
518: ec = REFERENCE_TYPE;
519: }
520:
521: /* the TREE_CODE of exprtype must match that of type. */
522: if (ec != tc)
523: {
524: cp_error ("`%E' (of type `%#T') fails to be of %s type", expr, exprtype,
525: tc == POINTER_TYPE ? "pointer" : "reference");
526: return error_mark_node;
527: }
528:
529: /* If *type is an unambiguous accessible base class of *exprtype,
530: convert statically. */
531: {
532: int distance;
533: tree path;
534:
535: distance = get_base_distance (TREE_TYPE (type), TREE_TYPE (exprtype), 1,
536: &path);
537: if (distance >= 0)
538: return build_vbase_path (PLUS_EXPR, type, expr, path, 0);
539: }
540:
541: /* Otherwise *exprtype must be a polymorphic class (have a vtbl). */
542: if (TYPE_VIRTUAL_P (TREE_TYPE (exprtype)))
543: {
544: /* if TYPE is `void *', return pointer to complete object. */
545: if (tc == POINTER_TYPE && TREE_TYPE (type) == void_type_node)
546: {
547: /* if b is an object, dynamic_cast<void *>(&b) == (void *)&b. */
548: if (TREE_CODE (expr) == ADDR_EXPR
549: && TREE_CODE (TREE_OPERAND (expr, 0)) == VAR_DECL
550: && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE)
551: return build1 (NOP_EXPR, type, expr);
552:
553: sorry ("finding pointer to complete object");
554: return build1 (NOP_EXPR, type, expr);
555: }
556: else
557: {
558: tree retval;
559:
560: /* If we got here, we can't convert statically. Therefore,
561: dynamic_cast<D&>(b) (b an object) cannot succeed. */
562: if (ec == REFERENCE_TYPE)
563: {
564: if (TREE_CODE (expr) == VAR_DECL
565: && TREE_CODE (TREE_TYPE (expr)) == RECORD_TYPE)
566: {
567: cp_warning ("dynamic_cast of `%#D' to `%#T' can never succeed",
568: expr, type);
569: /* cplus_expand_throw (Bad_cast_node); */
570: sorry ("throwing Bad_cast");
571: return error_mark_node;
572: }
573: }
574: /* Ditto for dynamic_cast<D*>(&b). */
575: else if (TREE_CODE (expr) == ADDR_EXPR)
576: {
577: tree op = TREE_OPERAND (expr, 0);
578: if (TREE_CODE (op) == VAR_DECL
579: && TREE_CODE (TREE_TYPE (op)) == RECORD_TYPE)
580: {
581: cp_warning ("dynamic_cast of `%E' to `%#T' can never succeed",
582: expr, type);
583: retval = build_int_2 (0, 0);
584: TREE_TYPE (retval) = type;
585: return retval;
586: }
587: }
588: /* Build run-time conversion. */
589: sorry ("run-time type conversion");
590: retval = build_int_2 (0, 0);
591: TREE_TYPE (retval) = type;
592: return retval;
593: }
594: }
595:
596: cp_error ("cannot dynamic_cast `%E' (of type `%#T') to type `%#T'",
597: expr, exprtype, type);
598: return error_mark_node;
599: }
600:
601: /* Build and initialize various sorts of descriptors. Every descriptor
602: node has a name associated with it (the name created by mangling).
603: For this reason, we use the identifier as our access to the __*_desc
604: nodes, instead of sticking them directly in the types. Otherwise we
605: would burden all built-in types (and pointer types) with slots that
606: we don't necessarily want to use.
607:
608: For each descriptor we build, we build a variable that contains
609: the descriptor's information. When we need this info at runtime,
610: all we need is access to these variables.
611:
612: Note: these constructors always return the address of the descriptor
613: info, since that is simplest for their mutual interaction. */
614:
615: static tree
616: build_generic_desc (decl, elems)
617: tree decl;
618: tree elems;
619: {
620: tree init = build (CONSTRUCTOR, TREE_TYPE (decl), NULL_TREE, elems);
621: TREE_CONSTANT (init) = 1;
622: TREE_STATIC (init) = 1;
623: TREE_READONLY (init) = 1;
624:
625: DECL_INITIAL (decl) = init;
626: TREE_STATIC (decl) = 1;
627: layout_decl (decl, 0);
628: finish_decl (decl, init, 0, 0);
629:
630: return IDENTIFIER_AS_DESC (DECL_NAME (decl));
631: }
632:
633: /* Build an initializer for a __t_desc node. So that we can take advantage
634: of recursion, we accept NULL for TYPE.
635: DEFINITION is greater than zero iff we must define the type descriptor
636: (as opposed to merely referencing it). 1 means treat according to
637: #pragma interface/#pragma implementation rules. 2 means define as
638: global and public, no matter what. */
639: tree
640: build_t_desc (type, definition)
641: tree type;
642: int definition;
643: {
644: tree tdecl;
645: tree tname, name_string;
646: tree elems, fields;
647: tree parents, vbases, offsets, ivars, methods, target_type;
648: int method_count = 0, field_count = 0;
649:
650: if (type == NULL_TREE)
651: return NULL_TREE;
652:
653: tname = build_t_desc_overload (type);
654: if (IDENTIFIER_AS_DESC (tname)
655: && (!definition || TREE_ASM_WRITTEN (IDENTIFIER_AS_DESC (tname))))
656: return IDENTIFIER_AS_DESC (tname);
657:
658: tdecl = lookup_name (tname, 0);
659: if (tdecl == NULL_TREE)
660: {
661: tdecl = build_decl (VAR_DECL, tname, __t_desc_type_node);
662: DECL_EXTERNAL (tdecl) = 1;
663: TREE_PUBLIC (tdecl) = 1;
664: tdecl = pushdecl_top_level (tdecl);
665: }
666: /* If we previously defined it, return the defined result. */
667: else if (definition && DECL_INITIAL (tdecl))
668: return IDENTIFIER_AS_DESC (tname);
669:
670: if (definition)
671: {
672: tree taggr = type;
673: /* Let T* and T& be written only when T is written (if T is an aggr).
674: We do this for const, but not for volatile, since volatile
675: is rare and const is not. */
676: if (!TYPE_VOLATILE (taggr)
677: && (TREE_CODE (taggr) == POINTER_TYPE
678: || TREE_CODE (taggr) == REFERENCE_TYPE)
679: && IS_AGGR_TYPE (TREE_TYPE (taggr)))
680: taggr = TREE_TYPE (taggr);
681:
682: /* If we know that we don't need to write out this type's
683: vtable, then don't write out it's dossier. Somebody
684: else will take care of that. */
685: if (IS_AGGR_TYPE (taggr) && CLASSTYPE_VFIELD (taggr))
686: {
687: if (CLASSTYPE_VTABLE_NEEDS_WRITING (taggr))
688: {
689: TREE_PUBLIC (tdecl) = ! CLASSTYPE_INTERFACE_ONLY (taggr)
690: && CLASSTYPE_INTERFACE_KNOWN (taggr);
691: TREE_STATIC (tdecl) = 1;
692: DECL_EXTERNAL (tdecl) = 0;
693: }
694: else
695: {
696: if (write_virtuals != 0)
697: TREE_PUBLIC (tdecl) = 1;
698: }
699: }
700: else
701: {
702: DECL_EXTERNAL (tdecl) = 0;
703: TREE_STATIC (tdecl) = 1;
704: TREE_PUBLIC (tdecl) = (definition > 1);
705: }
706: }
707: SET_IDENTIFIER_AS_DESC (tname, build_unary_op (ADDR_EXPR, tdecl, 0));
708: if (!definition || DECL_EXTERNAL (tdecl))
709: {
710: /* That's it! */
711: finish_decl (tdecl, 0, 0, 0);
712: return IDENTIFIER_AS_DESC (tname);
713: }
714:
715: /* Show that we are defining the t_desc for this type. */
716: DECL_INITIAL (tdecl) = error_mark_node;
717:
718: parents = build_tree_list (NULL_TREE, integer_zero_node);
719: vbases = build_tree_list (NULL_TREE, integer_zero_node);
720: offsets = build_tree_list (NULL_TREE, integer_zero_node);
721: methods = NULL_TREE;
722: ivars = NULL_TREE;
723:
724: if (TYPE_LANG_SPECIFIC (type))
725: {
726: int i = CLASSTYPE_N_BASECLASSES (type);
727: tree method_vec = CLASSTYPE_METHOD_VEC (type);
728: tree *meth, *end;
729: tree binfos = TYPE_BINFO_BASETYPES (type);
730: tree vb = CLASSTYPE_VBASECLASSES (type);
731:
732: while (--i >= 0)
733: parents = tree_cons (NULL_TREE, build_t_desc (BINFO_TYPE (TREE_VEC_ELT (binfos, i)), 0), parents);
734:
735: while (vb)
736: {
737: vbases = tree_cons (NULL_TREE, build_t_desc (BINFO_TYPE (vb), 0), vbases);
738: offsets = tree_cons (NULL_TREE, BINFO_OFFSET (vb), offsets);
739: vb = TREE_CHAIN (vb);
740: }
741:
742: if (method_vec)
743: for (meth = TREE_VEC_END (method_vec),
744: end = &TREE_VEC_ELT (method_vec, 0); meth-- != end; )
745: if (*meth)
746: {
747: methods = tree_cons (NULL_TREE, build_m_desc (*meth), methods);
748: method_count++;
749: }
750: }
751:
752: if (IS_AGGR_TYPE (type))
753: {
754: for (fields = TYPE_FIELDS (type); fields; fields = TREE_CHAIN (fields))
755: if (TREE_CODE (fields) == FIELD_DECL
756: || TREE_CODE (fields) == VAR_DECL)
757: {
758: ivars = tree_cons (NULL_TREE, build_i_desc (fields), ivars);
759: field_count++;
760: }
761: ivars = nreverse (ivars);
762: }
763:
764: parents = finish_table (0, TYPE_POINTER_TO (__t_desc_type_node), parents, 0);
765: vbases = finish_table (0, TYPE_POINTER_TO (__t_desc_type_node), vbases, 0);
766: offsets = finish_table (0, integer_type_node, offsets, 0);
767: if (methods == NULL_TREE)
768: methods = null_pointer_node;
769: else
770: methods = build_unary_op (ADDR_EXPR,
771: finish_table (0, __m_desc_type_node, methods, 0),
772: 0);
773: if (ivars == NULL_TREE)
774: ivars = null_pointer_node;
775: else
776: ivars = build_unary_op (ADDR_EXPR,
777: finish_table (0, __i_desc_type_node, ivars, 0),
778: 0);
779: if (TREE_TYPE (type))
780: target_type = build_t_desc (TREE_TYPE (type), definition);
781: else
782: target_type = integer_zero_node;
783:
784: name_string = combine_strings (build_string (IDENTIFIER_LENGTH (tname)+1, IDENTIFIER_POINTER (tname)));
785:
786: elems = tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, name_string, 0),
787: tree_cons (NULL_TREE,
788: TYPE_SIZE(type)? size_in_bytes(type) : integer_zero_node,
789: /* really should use bitfield initialization here. */
790: tree_cons (NULL_TREE, integer_zero_node,
791: tree_cons (NULL_TREE, target_type,
792: tree_cons (NULL_TREE, build_int_2 (field_count, 2),
793: tree_cons (NULL_TREE, build_int_2 (method_count, 2),
794: tree_cons (NULL_TREE, ivars,
795: tree_cons (NULL_TREE, methods,
796: tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, parents, 0),
797: tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, vbases, 0),
798: build_tree_list (NULL_TREE, build_unary_op (ADDR_EXPR, offsets, 0))))))))))));
799: return build_generic_desc (tdecl, elems);
800: }
801:
802: /* Build an initializer for a __i_desc node. */
803: tree
804: build_i_desc (decl)
805: tree decl;
806: {
807: tree elems, name_string;
808: tree taggr;
809:
810: name_string = DECL_NAME (decl);
811: name_string = combine_strings (build_string (IDENTIFIER_LENGTH (name_string)+1, IDENTIFIER_POINTER (name_string)));
812:
813: /* Now decide whether this ivar should cause it's type to get
814: def'd or ref'd in this file. If the type we are looking at
815: has a proxy definition, we look at the proxy (i.e., a
816: `foo *' is equivalent to a `foo'). */
817: taggr = TREE_TYPE (decl);
818:
819: if ((TREE_CODE (taggr) == POINTER_TYPE
820: || TREE_CODE (taggr) == REFERENCE_TYPE)
821: && TYPE_VOLATILE (taggr) == 0)
822: taggr = TREE_TYPE (taggr);
823:
824: elems = tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, name_string, 0),
825: tree_cons (NULL_TREE, DECL_FIELD_BITPOS (decl),
826: build_tree_list (NULL_TREE, build_t_desc (TREE_TYPE (decl),
827: ! IS_AGGR_TYPE (taggr)))));
828: taggr = build (CONSTRUCTOR, __i_desc_type_node, NULL_TREE, elems);
829: TREE_CONSTANT (taggr) = 1;
830: TREE_STATIC (taggr) = 1;
831: TREE_READONLY (taggr) = 1;
832: return taggr;
833: }
834:
835: /* Build an initializer for a __m_desc node. */
836: tree
837: build_m_desc (decl)
838: tree decl;
839: {
840: tree taggr, elems, name_string;
841: tree parm_count, req_count, vindex, vcontext;
842: tree parms;
843: int p_count, r_count;
844: tree parm_types = NULL_TREE;
845:
846: for (parms = TYPE_ARG_TYPES (TREE_TYPE (decl)), p_count = 0, r_count = 0;
847: parms != NULL_TREE; parms = TREE_CHAIN (parms), p_count++)
848: {
849: taggr = TREE_VALUE (parms);
850: if ((TREE_CODE (taggr) == POINTER_TYPE
851: || TREE_CODE (taggr) == REFERENCE_TYPE)
852: && TYPE_VOLATILE (taggr) == 0)
853: taggr = TREE_TYPE (taggr);
854:
855: parm_types = tree_cons (NULL_TREE, build_t_desc (TREE_VALUE (parms),
856: ! IS_AGGR_TYPE (taggr)),
857: parm_types);
858: if (TREE_PURPOSE (parms) == NULL_TREE)
859: r_count++;
860: }
861:
862: parm_types = finish_table (0, TYPE_POINTER_TO (__t_desc_type_node),
863: nreverse (parm_types), 0);
864: parm_count = build_int_2 (p_count, 0);
865: req_count = build_int_2 (r_count, 0);
866:
867: if (DECL_VINDEX (decl))
868: vindex = DECL_VINDEX (decl);
869: else
870: vindex = integer_zero_node;
871: if (DECL_CONTEXT (decl)
872: && TREE_CODE_CLASS (TREE_CODE (DECL_CONTEXT (decl))) == 't')
873: vcontext = build_t_desc (DECL_CONTEXT (decl), 0);
874: else
875: vcontext = integer_zero_node;
876: name_string = DECL_NAME (decl);
877: if (name_string == NULL)
878: name_string = DECL_ASSEMBLER_NAME (decl);
879: name_string = combine_strings (build_string (IDENTIFIER_LENGTH (name_string)+1, IDENTIFIER_POINTER (name_string)));
880:
881: /* Now decide whether the return type of this mvar
882: should cause it's type to get def'd or ref'd in this file.
883: If the type we are looking at has a proxy definition,
884: we look at the proxy (i.e., a `foo *' is equivalent to a `foo'). */
885: taggr = TREE_TYPE (TREE_TYPE (decl));
886:
887: if ((TREE_CODE (taggr) == POINTER_TYPE
888: || TREE_CODE (taggr) == REFERENCE_TYPE)
889: && TYPE_VOLATILE (taggr) == 0)
890: taggr = TREE_TYPE (taggr);
891:
892: elems = tree_cons (NULL_TREE, build_unary_op (ADDR_EXPR, name_string, 0),
893: tree_cons (NULL_TREE, vindex,
894: tree_cons (NULL_TREE, vcontext,
895: tree_cons (NULL_TREE, build_t_desc (TREE_TYPE (TREE_TYPE (decl)),
896: ! IS_AGGR_TYPE (taggr)),
897: tree_cons (NULL_TREE, build_c_cast (TYPE_POINTER_TO (default_function_type), build_unary_op (ADDR_EXPR, decl, 0)),
898: tree_cons (NULL_TREE, parm_count,
899: tree_cons (NULL_TREE, req_count,
900: build_tree_list (NULL_TREE, build_unary_op (ADDR_EXPR, parm_types, 0)))))))));
901:
902: taggr = build (CONSTRUCTOR, __m_desc_type_node, NULL_TREE, elems);
903: TREE_CONSTANT (taggr) = 1;
904: TREE_STATIC (taggr) = 1;
905: TREE_READONLY (taggr) = 1;
906: return taggr;
907: }
908:
909: /* Conditionally emit code to set up an unwind-protect for the
910: garbage collector. If this function doesn't do anything that involves
911: the garbage collector, then do nothing. Otherwise, call __gc_push
912: at the beginning and __gc_pop at the end.
913:
914: NOTE! The __gc_pop function must operate transparently, since
915: it comes where the logical return label lies. This means that
916: at runtime *it* must preserve any return value registers. */
917:
918: void
919: expand_gc_prologue_and_epilogue ()
920: {
921: extern tree maybe_gc_cleanup;
922: struct rtx_def *last_parm_insn, *mark;
923: extern struct rtx_def *get_last_insn ();
924: extern struct rtx_def *get_first_nonparm_insn ();
925: extern struct rtx_def *previous_insn ();
926: tree action;
927:
928: /* If we didn't need the obstack, don't cons any space. */
929: if (current_function_obstack_index == 0
930: || current_function_obstack_usage == 0)
931: return;
932:
933: mark = get_last_insn ();
934: last_parm_insn = get_first_nonparm_insn ();
935: if (last_parm_insn == 0) last_parm_insn = mark;
936: else last_parm_insn = previous_insn (last_parm_insn);
937:
938: action = build_function_call (gc_push_fndecl,
939: build_tree_list (NULL_TREE, size_int (++current_function_obstack_index)));
940: expand_expr_stmt (action);
941:
942: reorder_insns (next_insn (mark), get_last_insn (), last_parm_insn);
943:
944: /* This will be expanded as a cleanup. */
945: TREE_VALUE (maybe_gc_cleanup)
946: = build_function_call (gc_pop_fndecl, NULL_TREE);
947: }
948:
949: /* Some day we'll use this function as a call-back and clean
950: up all the unnecessary gc dribble that we otherwise create. */
951: void
952: lang_expand_end_bindings (first, last)
953: struct rtx_def *first, *last;
954: {
955: }
956:
957: void
958: init_gc_processing ()
959: {
960: tree parmtypes = hash_tree_chain (class_star_type_node,
961: hash_tree_chain (integer_type_node, NULL_TREE));
962: gc_protect_fndecl = define_function ("__gc_protect",
963: build_function_type (class_star_type_node, parmtypes),
964: NOT_BUILT_IN, 0, 0);
965:
966: parmtypes = hash_tree_chain (integer_type_node, NULL_TREE);
967: gc_unprotect_fndecl = define_function ("__gc_unprotect",
968: build_function_type (void_type_node, parmtypes),
969: NOT_BUILT_IN, 0, 0);
970:
971: gc_push_fndecl = define_function ("__gc_push",
972: TREE_TYPE (gc_unprotect_fndecl),
973: NOT_BUILT_IN, 0, 0);
974:
975: gc_pop_fndecl = define_function ("__gc_pop",
976: build_function_type (void_type_node,
977: void_list_node),
978: NOT_BUILT_IN, 0, 0);
979: gc_nonobject = build_int_2 (0x80000000, 0);
980: gc_visible = build_int_2 (0x40000000, 0);
981: gc_white = integer_zero_node;
982: gc_offwhite = build_int_2 (0x10000000, 0);
983: gc_grey = build_int_2 (0x20000000, 0);
984: gc_black = build_int_2 (0x30000000, 0);
985: }
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