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1.1 root 1: /* This file contains the definitions and documentation for the
2: tree codes used in the GNU C compiler.
1.1.1.6 ! root 3: Copyright (C) 1987, 1988, 1993, 1995 Free Software Foundation, Inc.
1.1 root 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
1.1.1.6 ! root 19: the Free Software Foundation, 59 Temple Place - Suite 330,
! 20: Boston, MA 02111-1307, USA. */
1.1 root 21:
22:
23: /* The third argument can be:
24: "x" for an exceptional code (fits no category).
25: "t" for a type object code.
1.1.1.2 root 26: "b" for a lexical block.
1.1 root 27: "c" for codes for constants.
28: "d" for codes for declarations (also serving as variable refs).
29: "r" for codes for references to storage.
30: "<" for codes for comparison expressions.
31: "1" for codes for unary arithmetic expressions.
32: "2" for codes for binary arithmetic expressions.
33: "s" for codes for expressions with inherent side effects.
34: "e" for codes for other kinds of expressions. */
35:
36: /* For `r', `e', `<', `1', `2', `s' and `x' nodes,
37: the 4th element is the number of argument slots to allocate.
38: This determines the size of the tree node object. */
39:
40: /* Any erroneous construct is parsed into a node of this type.
41: This type of node is accepted without complaint in all contexts
42: by later parsing activities, to avoid multiple error messages
43: for one error.
44: No fields in these nodes are used except the TREE_CODE. */
45: DEFTREECODE (ERROR_MARK, "error_mark", "x", 0)
46:
47: /* Used to represent a name (such as, in the DECL_NAME of a decl node).
48: Internally it looks like a STRING_CST node.
49: There is only one IDENTIFIER_NODE ever made for any particular name.
50: Use `get_identifier' to get it (or create it, the first time). */
51: DEFTREECODE (IDENTIFIER_NODE, "identifier_node", "x", -1)
52:
53: /* Used to hold information to identify an operator (or combination
54: of two operators) considered as a `noun' rather than a `verb'.
55: The first operand is encoded in the TREE_TYPE field. */
56: DEFTREECODE (OP_IDENTIFIER, "op_identifier", "x", 2)
57:
58: /* Has the TREE_VALUE and TREE_PURPOSE fields. */
59: /* These nodes are made into lists by chaining through the
60: TREE_CHAIN field. The elements of the list live in the
61: TREE_VALUE fields, while TREE_PURPOSE fields are occasionally
62: used as well to get the effect of Lisp association lists. */
63: DEFTREECODE (TREE_LIST, "tree_list", "x", 2)
64:
65: /* These nodes contain an array of tree nodes. */
66: DEFTREECODE (TREE_VEC, "tree_vec", "x", 2)
67:
68: /* A symbol binding block. These are arranged in a tree,
69: where the BLOCK_SUBBLOCKS field contains a chain of subblocks
70: chained through the BLOCK_CHAIN field.
71: BLOCK_SUPERCONTEXT points to the parent block.
1.1.1.2 root 72: For a block which represents the outermost scope of a function, it
73: points to the FUNCTION_DECL node.
1.1 root 74: BLOCK_VARS points to a chain of decl nodes.
75: BLOCK_TYPE_TAGS points to a chain of types which have their own names.
1.1.1.2 root 76: BLOCK_CHAIN points to the next BLOCK at the same level.
77: BLOCK_ABSTRACT_ORIGIN points to the original (abstract) tree node which
78: this block is an instance of, or else is NULL to indicate that this
79: block is not an instance of anything else. When non-NULL, the value
80: could either point to another BLOCK node or it could point to a
81: FUNCTION_DECL node (e.g. in the case of a block representing the
82: outermost scope of a particular inlining of a function).
83: BLOCK_ABSTRACT is non-zero if the block represents an abstract
84: instance of a block (i.e. one which is nested within an abstract
85: instance of a inline function. */
86: DEFTREECODE (BLOCK, "block", "b", 0)
1.1 root 87:
88: /* Each data type is represented by a tree node whose code is one of
89: the following: */
90: /* Each node that represents a data type has a component TYPE_SIZE
91: containing a tree that is an expression for the size in bits.
92: The TYPE_MODE contains the machine mode for values of this type.
93: The TYPE_POINTER_TO field contains a type for a pointer to this type,
94: or zero if no such has been created yet.
95: The TYPE_NEXT_VARIANT field is used to chain together types
96: that are variants made by type modifiers such as "const" and "volatile".
97: The TYPE_MAIN_VARIANT field, in any member of such a chain,
98: points to the start of the chain.
99: The TYPE_NONCOPIED_PARTS field is a list specifying which parts
100: of an object of this type should *not* be copied by assignment.
101: The TREE_PURPOSE of each element is the offset of the part
102: and the TREE_VALUE is the size in bits of the part.
103: The TYPE_NAME field contains info on the name used in the program
104: for this type (for GDB symbol table output). It is either a
105: TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
106: in the case of structs, unions or enums that are known with a tag,
107: or zero for types that have no special name.
1.1.1.2 root 108: The TYPE_CONTEXT for any sort of type which could have a name or
109: which could have named members (e.g. tagged types in C/C++) will
110: point to the node which represents the scope of the given type, or
111: will be NULL_TREE if the type has "file scope". For most types, this
112: will point to a BLOCK node or a FUNCTION_DECL node, but it could also
113: point to a FUNCTION_TYPE node (for types whose scope is limited to the
1.1 root 114: formal parameter list of some function type specification) or it
1.1.1.3 root 115: could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
116: (for C++ "member" types).
1.1 root 117: For non-tagged-types, TYPE_CONTEXT need not be set to anything in
1.1.1.2 root 118: particular, since any type which is of some type category (e.g.
119: an array type or a function type) which cannot either have a name
1.1.1.3 root 120: itself or have named members doesn't really have a "scope" per se.
121: The TREE_CHAIN field is used as a forward-references to names for
122: ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
123: see below. */
1.1 root 124:
125: DEFTREECODE (VOID_TYPE, "void_type", "t", 0) /* The void type in C */
126:
1.1.1.3 root 127: /* Integer types in all languages, including char in C.
128: Also used for sub-ranges of other discrete types.
129: Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
1.1 root 130: and TYPE_PRECISION (number of bits used by this type).
131: In the case of a subrange type in Pascal, the TREE_TYPE
1.1.1.3 root 132: of this will point at the supertype (another INTEGER_TYPE,
133: or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
1.1 root 134: Otherwise, the TREE_TYPE is zero. */
135: DEFTREECODE (INTEGER_TYPE, "integer_type", "t", 0)
136:
137: /* C's float and double. Different floating types are distinguished
138: by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
139: DEFTREECODE (REAL_TYPE, "real_type", "t", 0)
140:
141: /* Complex number types. The TREE_TYPE field is the data type
142: of the real and imaginary parts. */
143: DEFTREECODE (COMPLEX_TYPE, "complex_type", "t", 0)
144:
145: /* C enums. The type node looks just like an INTEGER_TYPE node.
146: The symbols for the values of the enum type are defined by
147: CONST_DECL nodes, but the type does not point to them;
1.1.1.3 root 148: however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
1.1 root 149: is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
150: /* A forward reference `enum foo' when no enum named foo is defined yet
151: has zero (a null pointer) in its TYPE_SIZE. The tag name is in
152: the TYPE_NAME field. If the type is later defined, the normal
153: fields are filled in.
1.1.1.3 root 154: RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
155: treated similarly. */
1.1 root 156: DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", "t", 0)
157:
158: /* Pascal's boolean type (true or false are the only values);
159: no special fields needed. */
160: DEFTREECODE (BOOLEAN_TYPE, "boolean_type", "t", 0)
161:
162: /* CHAR in Pascal; not used in C.
163: No special fields needed. */
164: DEFTREECODE (CHAR_TYPE, "char_type", "t", 0)
165:
166: /* All pointer-to-x types have code POINTER_TYPE.
167: The TREE_TYPE points to the node for the type pointed to. */
168: DEFTREECODE (POINTER_TYPE, "pointer_type", "t", 0)
169:
170: /* An offset is a pointer relative to an object.
171: The TREE_TYPE field is the type of the object at the offset.
172: The TYPE_OFFSET_BASETYPE points to the node for the type of object
173: that the offset is relative to. */
174: DEFTREECODE (OFFSET_TYPE, "offset_type", "t", 0)
175:
176: /* A reference is like a pointer except that it is coerced
177: automatically to the value it points to. Used in C++. */
178: DEFTREECODE (REFERENCE_TYPE, "reference_type", "t", 0)
179:
180: /* METHOD_TYPE is the type of a function which takes an extra first
181: argument for "self", which is not present in the declared argument list.
182: The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
183: is the type of "self". TYPE_ARG_TYPES is the real argument list, which
184: includes the hidden argument for "self". */
185: DEFTREECODE (METHOD_TYPE, "method_type", "t", 0)
186:
187: /* Used for Pascal; details not determined right now. */
188: DEFTREECODE (FILE_TYPE, "file_type", "t", 0)
189:
190: /* Types of arrays. Special fields:
191: TREE_TYPE Type of an array element.
192: TYPE_DOMAIN Type to index by.
193: Its range of values specifies the array length.
194: TYPE_SEP Expression for units from one elt to the next.
195: TYPE_SEP_UNIT Number of bits in a unit for previous.
196: The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
1.1.1.5 root 197: and holds the type to coerce a value of that array type to in C.
198: TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
199: in languages (such as Chill) that make a distinction. */
1.1 root 200: /* Array types in C or Pascal */
201: DEFTREECODE (ARRAY_TYPE, "array_type", "t", 0)
202:
203: /* Types of sets for Pascal. Special fields are the same as
1.1.1.6 ! root 204: in an array type. The target type is always a boolean type.
! 205: Used for both bitstrings and powersets in Chill;
! 206: TYPE_STRING_FLAG indicates a bitstring. */
1.1 root 207: DEFTREECODE (SET_TYPE, "set_type", "t", 0)
208:
209: /* Struct in C, or record in Pascal. */
210: /* Special fields:
211: TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct.
212: A few may need to be added for Pascal. */
213: /* See the comment above, before ENUMERAL_TYPE, for how
214: forward references to struct tags are handled in C. */
215: DEFTREECODE (RECORD_TYPE, "record_type", "t", 0)
216:
217: /* Union in C. Like a struct, except that the offsets of the fields
218: will all be zero. */
219: /* See the comment above, before ENUMERAL_TYPE, for how
220: forward references to union tags are handled in C. */
221: DEFTREECODE (UNION_TYPE, "union_type", "t", 0) /* C union type */
222:
1.1.1.3 root 223: /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
224: in each FIELD_DECL determine what the union contains. The first
225: field whose DECL_QUALIFIER expression is true is deemed to occupy
226: the union. */
227: DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", "t", 0)
228:
1.1 root 229: /* Type of functions. Special fields:
230: TREE_TYPE type of value returned.
231: TYPE_ARG_TYPES list of types of arguments expected.
232: this list is made of TREE_LIST nodes.
233: Types of "Procedures" in languages where they are different from functions
234: have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
235: DEFTREECODE (FUNCTION_TYPE, "function_type", "t", 0)
236:
237: /* This is a language-specific kind of type.
238: Its meaning is defined by the language front end.
239: layout_type does not know how to lay this out,
240: so the front-end must do so manually. */
241: DEFTREECODE (LANG_TYPE, "lang_type", "t", 0)
242:
243: /* Expressions */
244:
245: /* First, the constants. */
246:
247: /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
248: 32 bits each, giving us a 64 bit constant capability.
249: Note: constants of type char in Pascal are INTEGER_CST,
250: and so are pointer constants such as nil in Pascal or NULL in C.
251: `(int *) 1' in C also results in an INTEGER_CST. */
252: DEFTREECODE (INTEGER_CST, "integer_cst", "c", 2)
253:
254: /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
255: DEFTREECODE (REAL_CST, "real_cst", "c", 3)
256:
257: /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
258: whose contents are other constant nodes.
259: Also there is TREE_CST_RTL. */
260: DEFTREECODE (COMPLEX_CST, "complex_cst", "c", 3)
261:
262: /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
263: Also there is TREE_CST_RTL. */
264: DEFTREECODE (STRING_CST, "string_cst", "c", 3)
265:
266: /* Declarations. All references to names are represented as ..._DECL nodes.
267: The decls in one binding context are chained through the TREE_CHAIN field.
268: Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
269: (Some decls, most often labels, may have zero as the DECL_NAME).
270: DECL_CONTEXT points to the node representing the context in which
271: this declaration has its scope. For FIELD_DECLs, this is the
1.1.1.3 root 272: RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
273: is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
274: and CONST_DECL nodes, this points to the FUNCTION_DECL for the
275: containing function, or else yields NULL_TREE if the given decl
276: has "file scope".
1.1.1.2 root 277: DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
278: ..._DECL node of which this decl is an (inlined or template expanded)
279: instance.
1.1 root 280: The TREE_TYPE field holds the data type of the object, when relevant.
281: LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
282: contents are the type whose name is being declared.
283: The DECL_ALIGN, DECL_SIZE,
284: and DECL_MODE fields exist in decl nodes just as in type nodes.
285: They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
286:
287: DECL_OFFSET holds an integer number of bits offset for the location.
288: DECL_VOFFSET holds an expression for a variable offset; it is
289: to be multiplied by DECL_VOFFSET_UNIT (an integer).
290: These fields are relevant only in FIELD_DECLs and PARM_DECLs.
291:
292: DECL_INITIAL holds the value to initialize a variable to,
293: or the value of a constant. For a function, it holds the body
294: (a node of type BLOCK representing the function's binding contour
295: and whose body contains the function's statements.) For a LABEL_DECL
296: in C, it is a flag, nonzero if the label's definition has been seen.
297:
298: PARM_DECLs use a special field:
299: DECL_ARG_TYPE is the type in which the argument is actually
300: passed, which may be different from its type within the function.
301:
302: FUNCTION_DECLs use four special fields:
303: DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
304: DECL_RESULT holds a RESULT_DECL node for the value of a function,
305: or it is 0 for a function that returns no value.
306: (C functions returning void have zero here.)
307: DECL_RESULT_TYPE holds the type in which the result is actually
308: returned. This is usually the same as the type of DECL_RESULT,
309: but (1) it may be a wider integer type and
310: (2) it remains valid, for the sake of inlining, even after the
311: function's compilation is done.
312: DECL_FUNCTION_CODE is a code number that is nonzero for
313: built-in functions. Its value is an enum built_in_function
314: that says which built-in function it is.
315:
316: DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
317: holds a line number. In some cases these can be the location of
1.1.1.2 root 318: a reference, if no definition has been seen.
319:
320: DECL_ABSTRACT is non-zero if the decl represents an abstract instance
321: of a decl (i.e. one which is nested within an abstract instance of a
322: inline function. */
1.1 root 323:
324: DEFTREECODE (FUNCTION_DECL, "function_decl", "d", 0)
325: DEFTREECODE (LABEL_DECL, "label_decl", "d", 0)
326: DEFTREECODE (CONST_DECL, "const_decl", "d", 0)
327: DEFTREECODE (TYPE_DECL, "type_decl", "d", 0)
328: DEFTREECODE (VAR_DECL, "var_decl", "d", 0)
329: DEFTREECODE (PARM_DECL, "parm_decl", "d", 0)
330: DEFTREECODE (RESULT_DECL, "result_decl", "d", 0)
331: DEFTREECODE (FIELD_DECL, "field_decl", "d", 0)
332:
333: /* References to storage. */
334:
335: /* Value is structure or union component.
336: Operand 0 is the structure or union (an expression);
337: operand 1 is the field (a node of type FIELD_DECL). */
338: DEFTREECODE (COMPONENT_REF, "component_ref", "r", 2)
339:
340: /* Reference to a group of bits within an object. Similar to COMPONENT_REF
341: except the position is given explicitly rather than via a FIELD_DECL.
342: Operand 0 is the structure or union expression;
343: operand 1 is a tree giving the number of bits being referenced;
344: operand 2 is a tree giving the position of the first referenced bit.
345: The field can be either a signed or unsigned field;
346: TREE_UNSIGNED says which. */
347: DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", "r", 3)
348:
349: /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
350: DEFTREECODE (INDIRECT_REF, "indirect_ref", "r", 1)
351:
352: /* Reference to the contents of an offset
353: (a value whose type is an OFFSET_TYPE).
354: Operand 0 is the object within which the offset is taken.
355: Operand 1 is the offset. */
356: DEFTREECODE (OFFSET_REF, "offset_ref", "r", 2)
357:
358: /* Pascal `^` on a file. One operand, an expression for the file. */
359: DEFTREECODE (BUFFER_REF, "buffer_ref", "r", 1)
360:
361: /* Array indexing in languages other than C.
362: Operand 0 is the array; operand 1 is a list of indices
363: stored as a chain of TREE_LIST nodes. */
364: DEFTREECODE (ARRAY_REF, "array_ref", "r", 2)
365:
366: /* Constructor: return an aggregate value made from specified components.
367: In C, this is used only for structure and array initializers.
368: The first "operand" is really a pointer to the RTL,
369: for constant constructors only.
370: The second operand is a list of component values
371: made out of a chain of TREE_LIST nodes. */
372: DEFTREECODE (CONSTRUCTOR, "constructor", "e", 2)
373:
374: /* The expression types are mostly straightforward,
375: with the fourth argument of DEFTREECODE saying
376: how many operands there are.
377: Unless otherwise specified, the operands are expressions. */
378:
379: /* Contains two expressions to compute, one followed by the other.
380: the first value is ignored. The second one's value is used. */
381: DEFTREECODE (COMPOUND_EXPR, "compound_expr", "e", 2)
382:
383: /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
384: DEFTREECODE (MODIFY_EXPR, "modify_expr", "e", 2)
385:
386: /* Initialization expression. Operand 0 is the variable to initialize;
387: Operand 1 is the initializer. */
388: DEFTREECODE (INIT_EXPR, "init_expr", "e", 2)
389:
390: /* For TARGET_EXPR, operand 0 is the target of an initialization,
391: operand 1 is the initializer for the target,
392: and operand 2 is the cleanup for this node, if any. */
393: DEFTREECODE (TARGET_EXPR, "target_expr", "e", 3)
394:
395: /* Conditional expression ( ... ? ... : ... in C).
396: Operand 0 is the condition.
397: Operand 1 is the then-value.
398: Operand 2 is the else-value. */
399: DEFTREECODE (COND_EXPR, "cond_expr", "e", 3)
400:
401: /* Declare local variables, including making RTL and allocating space.
402: Operand 0 is a chain of VAR_DECL nodes for the variables.
403: Operand 1 is the body, the expression to be computed using
404: the variables. The value of operand 1 becomes that of the BIND_EXPR.
405: Operand 2 is the BLOCK that corresponds to these bindings
406: for debugging purposes. If this BIND_EXPR is actually expanded,
407: that sets the TREE_USED flag in the BLOCK.
408:
409: The BIND_EXPR is not responsible for informing parsers
410: about these variables. If the body is coming from the input file,
411: then the code that creates the BIND_EXPR is also responsible for
412: informing the parser of the variables.
413:
414: If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
415: This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
416: If the BIND_EXPR should be output for debugging but will not be expanded,
417: set the TREE_USED flag by hand.
418:
419: In order for the BIND_EXPR to be known at all, the code that creates it
420: must also install it as a subblock in the tree of BLOCK
421: nodes for the function. */
422: DEFTREECODE (BIND_EXPR, "bind_expr", "e", 3)
423:
424: /* Function call. Operand 0 is the function.
425: Operand 1 is the argument list, a list of expressions
426: made out of a chain of TREE_LIST nodes.
427: There is no operand 2. That slot is used for the
428: CALL_EXPR_RTL macro (see preexpand_calls). */
429: DEFTREECODE (CALL_EXPR, "call_expr", "e", 3)
430:
431: /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
432: Operand 1 is the expression for "self".
433: Operand 2 is the list of explicit arguments. */
434: DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", "e", 4)
435:
436: /* Specify a value to compute along with its corresponding cleanup.
437: Operand 0 argument is an expression whose value needs a cleanup.
438: Operand 1 is an RTL_EXPR which will eventually represent that value.
439: Operand 2 is the cleanup expression for the object.
440: The RTL_EXPR is used in this expression, which is how the expression
441: manages to act on the proper value.
1.1.1.5 root 442: The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
443: it exists, otherwise it is the responsibility of the caller to manually
444: call expand_cleanups_to, as needed. */
1.1 root 445: DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", "e", 3)
446:
1.1.1.5 root 447: /* Specify a cleanup point.
1.1.1.6 ! root 448: Operand 0 is an expression that may have cleanups. If it does, those
! 449: cleanups are executed after the expression is expanded.
! 450:
! 451: Note that if the expression is a reference to storage, it is forced out
! 452: of memory before the cleanups are run. This is necessary to handle
! 453: cases where the cleanups modify the storage referenced; in the
! 454: expression 't.i', if 't' is a struct with an integer member 'i' and a
! 455: cleanup which modifies 'i', the value of the expression depends on
! 456: whether the cleanup is run before or after 't.i' is evaluated. When
! 457: expand_expr is run on 't.i', it returns a MEM. This is not good enough;
! 458: the value of 't.i' must be forced out of memory.
! 459:
! 460: As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
! 461: BLKmode, because it will not be forced out of memory. */
1.1.1.5 root 462: DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", "e", 1)
463:
1.1.1.4 root 464: /* The following two codes are used in languages that have types where
465: the position and/or sizes of fields vary from object to object of the
466: same type, i.e., where some other field in the object contains a value
467: that is used in the computation of another field's offset or size.
468:
469: For example, a record type with a discriminant in Ada is such a type.
470: This mechanism is also used to create "fat pointers" for unconstrained
471: array types in Ada; the fat pointer is a structure one of whose fields is
472: a pointer to the actual array type and the other field is a pointer to a
473: template, which is a structure containing the bounds of the array. The
474: bounds in the type pointed to by the first field in the fat pointer refer
475: to the values in the template.
476:
477: These "self-references" are doing using a PLACEHOLDER_EXPR. This is a
478: node that will later be replaced with the object being referenced. Its type
479: is that of the object and selects which object to use from a chain of
480: references (see below).
481:
482: When we wish to evaluate a size or offset, we check it is contains a
483: placeholder. If it does, we construct a WITH_RECORD_EXPR that contains
484: both the expression we wish to evaluate and an expression within which the
485: object may be found. The latter expression is the object itself in
486: the simple case of an Ada record with discriminant, but it can be the
487: array in the case of an unconstrained array.
488:
489: In the latter case, we need the fat pointer, because the bounds of the
490: array can only be accessed from it. However, we rely here on the fact that
491: the expression for the array contains the dereference of the fat pointer
492: that obtained the array pointer.
493:
494: Accordingly, when looking for the object to substitute in place of
495: a PLACEHOLDER_EXPR, we look down the first operand of the expression
496: passed as the second operand to WITH_RECORD_EXPR until we find something
497: of the desired type or reach a constant. */
498:
499: /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
500: evaluating this expression. The type of this expression is used to
501: find the record to replace it. */
502: DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", "x", 0)
503:
504: /* Provide an expression that references a record to be used in place
505: of a PLACEHOLDER_EXPR. The record to be used is the record within
506: operand 1 that has the same type as the PLACEHOLDER_EXPR in
507: operand 0. */
508: DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", "e", 2)
509:
1.1 root 510: /* Simple arithmetic. Operands must have the same machine mode
511: and the value shares that mode. */
512: DEFTREECODE (PLUS_EXPR, "plus_expr", "2", 2)
513: DEFTREECODE (MINUS_EXPR, "minus_expr", "2", 2)
514: DEFTREECODE (MULT_EXPR, "mult_expr", "2", 2)
515:
516: /* Division for integer result that rounds the quotient toward zero. */
517: /* Operands must have the same machine mode.
518: In principle they may be real, but that is not currently supported.
519: The result is always fixed point, and it has the same type as the
520: operands if they are fixed point. */
521: DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", "2", 2)
522:
523: /* Division for integer result that rounds the quotient toward infinity. */
524: DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", "2", 2)
525:
526: /* Division for integer result that rounds toward minus infinity. */
527: DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", "2", 2)
528:
529: /* Division for integer result that rounds toward nearest integer. */
530: DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", "2", 2)
531:
532: /* Four kinds of remainder that go with the four kinds of division. */
533: DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", "2", 2)
534: DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", "2", 2)
535: DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", "2", 2)
536: DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", "2", 2)
537:
538: /* Division for real result. The two operands must have the same type.
539: In principle they could be integers, but currently only real
540: operands are supported. The result must have the same type
541: as the operands. */
542: DEFTREECODE (RDIV_EXPR, "rdiv_expr", "2", 2)
543:
544: /* Division which is not supposed to need rounding.
545: Used for pointer subtraction in C. */
546: DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", "2", 2)
547:
548: /* Conversion of real to fixed point: four ways to round,
549: like the four ways to divide.
550: CONVERT_EXPR can also be used to convert a real to an integer,
551: and that is what is used in languages that do not have ways of
552: specifying which of these is wanted. Maybe these are not needed. */
553: DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", "1", 1)
554: DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", "1", 1)
555: DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", "1", 1)
556: DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", "1", 1)
557:
558: /* Conversion of an integer to a real. */
559: DEFTREECODE (FLOAT_EXPR, "float_expr", "1", 1)
560:
561: /* Exponentiation. Operands may have any types;
562: constraints on value type are not known yet. */
563: DEFTREECODE (EXPON_EXPR, "expon_expr", "2", 2)
564:
565: /* Unary negation. Value has same type as operand. */
566: DEFTREECODE (NEGATE_EXPR, "negate_expr", "1", 1)
567:
568: DEFTREECODE (MIN_EXPR, "min_expr", "2", 2)
569: DEFTREECODE (MAX_EXPR, "max_expr", "2", 2)
570: DEFTREECODE (ABS_EXPR, "abs_expr", "1", 1)
571: DEFTREECODE (FFS_EXPR, "ffs_expr", "1", 1)
572:
573: /* Shift operations for shift and rotate.
574: Shift is supposed to mean logical shift if done on an
575: unsigned type, arithmetic shift on a signed type.
576: The second operand is the number of bits to
577: shift by, and must always have mode SImode.
578: The result has the same mode as the first operand. */
579: DEFTREECODE (LSHIFT_EXPR, "alshift_expr", "2", 2)
580: DEFTREECODE (RSHIFT_EXPR, "arshift_expr", "2", 2)
581: DEFTREECODE (LROTATE_EXPR, "lrotate_expr", "2", 2)
582: DEFTREECODE (RROTATE_EXPR, "rrotate_expr", "2", 2)
583:
584: /* Bitwise operations. Operands have same mode as result. */
585: DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", "2", 2)
586: DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", "2", 2)
587: DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", "2", 2)
588: DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", "2", 2)
589: DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", "1", 1)
590:
591: /* Combination of boolean values or of integers considered only
592: as zero or nonzero. ANDIF and ORIF allow the second operand
593: not to be computed if the value of the expression is determined
1.1.1.3 root 594: from the first operand. AND, OR, and XOR always compute the second
1.1 root 595: operand whether its value is needed or not (for side effects). */
596: DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", "e", 2)
597: DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", "e", 2)
1.1.1.4 root 598: DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", "e", 2)
599: DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", "e", 2)
600: DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", "e", 2)
1.1 root 601: DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", "e", 1)
602:
603: /* Relational operators.
604: `EQ_EXPR' and `NE_EXPR' are allowed for any types.
605: The others are allowed only for integer (or pointer or enumeral)
606: or real types.
607: In all cases the operands will have the same type,
608: and the value is always the type used by the language for booleans. */
609: DEFTREECODE (LT_EXPR, "lt_expr", "<", 2)
610: DEFTREECODE (LE_EXPR, "le_expr", "<", 2)
611: DEFTREECODE (GT_EXPR, "gt_expr", "<", 2)
612: DEFTREECODE (GE_EXPR, "ge_expr", "<", 2)
613: DEFTREECODE (EQ_EXPR, "eq_expr", "<", 2)
614: DEFTREECODE (NE_EXPR, "ne_expr", "<", 2)
615:
616: /* Operations for Pascal sets. Not used now. */
617: DEFTREECODE (IN_EXPR, "in_expr", "2", 2)
618: DEFTREECODE (SET_LE_EXPR, "set_le_expr", "<", 2)
619: DEFTREECODE (CARD_EXPR, "card_expr", "1", 1)
620: DEFTREECODE (RANGE_EXPR, "range_expr", "2", 2)
621:
622: /* Represents a conversion of type of a value.
623: All conversions, including implicit ones, must be
624: represented by CONVERT_EXPR nodes. */
625: DEFTREECODE (CONVERT_EXPR, "convert_expr", "1", 1)
626:
627: /* Represents a conversion expected to require no code to be generated. */
628: DEFTREECODE (NOP_EXPR, "nop_expr", "1", 1)
629:
630: /* Value is same as argument, but guaranteed not an lvalue. */
631: DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", "1", 1)
632:
633: /* Represents something we computed once and will use multiple times.
634: First operand is that expression. Second is the function decl
635: in which the SAVE_EXPR was created. The third operand is the RTL,
636: nonzero only after the expression has been computed. */
637: DEFTREECODE (SAVE_EXPR, "save_expr", "e", 3)
638:
639: /* Represents something whose RTL has already been expanded
640: as a sequence which should be emitted when this expression is expanded.
641: The first operand is the RTL to emit. It is the first of a chain of insns.
642: The second is the RTL expression for the result. */
643: DEFTREECODE (RTL_EXPR, "rtl_expr", "e", 2)
644:
645: /* & in C. Value is the address at which the operand's value resides.
646: Operand may have any mode. Result mode is Pmode. */
647: DEFTREECODE (ADDR_EXPR, "addr_expr", "e", 1)
648:
649: /* Non-lvalue reference or pointer to an object. */
650: DEFTREECODE (REFERENCE_EXPR, "reference_expr", "e", 1)
651:
652: /* Operand is a function constant; result is a function variable value
653: of typeEPmode. Used only for languages that need static chains. */
654: DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", "e", 1)
655:
656: /* Given two real or integer operands of the same type,
657: returns a complex value of the corresponding complex type. */
658: DEFTREECODE (COMPLEX_EXPR, "complex_expr", "2", 2)
659:
660: /* Complex conjugate of operand. Used only on complex types.
661: The value has the same type as the operand. */
662: DEFTREECODE (CONJ_EXPR, "conj_expr", "1", 1)
663:
664: /* Used only on an operand of complex type, these return
665: a value of the corresponding component type. */
666: DEFTREECODE (REALPART_EXPR, "realpart_expr", "1", 1)
667: DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", "1", 1)
668:
669: /* Nodes for ++ and -- in C.
670: The second arg is how much to increment or decrement by.
671: For a pointer, it would be the size of the object pointed to. */
672: DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", "e", 2)
673: DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", "e", 2)
674: DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", "e", 2)
675: DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", "e", 2)
676:
677: /* These types of expressions have no useful value,
678: and always have side effects. */
679:
680: /* A label definition, encapsulated as a statement.
681: Operand 0 is the LABEL_DECL node for the label that appears here.
682: The type should be void and the value should be ignored. */
683: DEFTREECODE (LABEL_EXPR, "label_expr", "s", 1)
684:
685: /* GOTO. Operand 0 is a LABEL_DECL node.
686: The type should be void and the value should be ignored. */
687: DEFTREECODE (GOTO_EXPR, "goto_expr", "s", 1)
688:
689: /* RETURN. Evaluates operand 0, then returns from the current function.
690: Presumably that operand is an assignment that stores into the
691: RESULT_DECL that hold the value to be returned.
692: The operand may be null.
693: The type should be void and the value should be ignored. */
694: DEFTREECODE (RETURN_EXPR, "return_expr", "s", 1)
695:
696: /* Exit the inner most loop conditionally. Operand 0 is the condition.
697: The type should be void and the value should be ignored. */
698: DEFTREECODE (EXIT_EXPR, "exit_expr", "s", 1)
699:
700: /* A loop. Operand 0 is the body of the loop.
701: It must contain an EXIT_EXPR or is an infinite loop.
702: The type should be void and the value should be ignored. */
703: DEFTREECODE (LOOP_EXPR, "loop_expr", "s", 1)
704:
705: /*
706: Local variables:
707: mode:c
708: version-control: t
709: End:
710: */
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