1 /* This file contains the definitions and documentation for the
2 tree codes used in GCC.
3 Copyright (C) 1987, 1988, 1993, 1995, 1997, 1998, 2000, 2001
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
24 /* The third argument can be:
25 'x' for an exceptional code (fits no category).
26 't' for a type object code.
27 'b' for a lexical block.
28 'c' for codes for constants.
29 'd' for codes for declarations (also serving as variable refs).
30 'r' for codes for references to storage.
31 '<' for codes for comparison expressions.
32 '1' for codes for unary arithmetic expressions.
33 '2' for codes for binary arithmetic expressions.
34 's' for codes for "statement" expressions, which have side-effects,
35 but usually no interesting value.
36 'e' for codes for other kinds of expressions. */
38 /* For `r', `e', `<', `1', `2', and `s' nodes, which use struct
39 tree_exp, the 4th element is the number of argument slots to
40 allocate. This determines the size of the tree node object.
41 Other nodes use different structures, and the size is determined
42 by the tree_union member structure; the 4th element should be
43 zero. Languages that define language-specific 'x' or 'c' codes
44 must define the tree_size langhook to say how big they are. */
46 /* Any erroneous construct is parsed into a node of this type.
47 This type of node is accepted without complaint in all contexts
48 by later parsing activities, to avoid multiple error messages
50 No fields in these nodes are used except the TREE_CODE. */
51 DEFTREECODE (ERROR_MARK, "error_mark", 'x', 0)
53 /* Used to represent a name (such as, in the DECL_NAME of a decl node).
54 Internally it looks like a STRING_CST node.
55 There is only one IDENTIFIER_NODE ever made for any particular name.
56 Use `get_identifier' to get it (or create it, the first time). */
57 DEFTREECODE (IDENTIFIER_NODE, "identifier_node", 'x', 0)
59 /* Has the TREE_VALUE and TREE_PURPOSE fields. */
60 /* These nodes are made into lists by chaining through the
61 TREE_CHAIN field. The elements of the list live in the
62 TREE_VALUE fields, while TREE_PURPOSE fields are occasionally
63 used as well to get the effect of Lisp association lists. */
64 DEFTREECODE (TREE_LIST, "tree_list", 'x', 0)
66 /* These nodes contain an array of tree nodes. */
67 DEFTREECODE (TREE_VEC, "tree_vec", 'x', 0)
69 /* A symbol binding block. These are arranged in a tree,
70 where the BLOCK_SUBBLOCKS field contains a chain of subblocks
71 chained through the BLOCK_CHAIN field.
72 BLOCK_SUPERCONTEXT points to the parent block.
73 For a block which represents the outermost scope of a function, it
74 points to the FUNCTION_DECL node.
75 BLOCK_VARS points to a chain of decl nodes.
76 BLOCK_TYPE_TAGS points to a chain of types which have their own names.
77 BLOCK_CHAIN points to the next BLOCK at the same level.
78 BLOCK_ABSTRACT_ORIGIN points to the original (abstract) tree node which
79 this block is an instance of, or else is NULL to indicate that this
80 block is not an instance of anything else. When non-NULL, the value
81 could either point to another BLOCK node or it could point to a
82 FUNCTION_DECL node (e.g. in the case of a block representing the
83 outermost scope of a particular inlining of a function).
84 BLOCK_ABSTRACT is nonzero if the block represents an abstract
85 instance of a block (i.e. one which is nested within an abstract
86 instance of an inline function).
87 TREE_ASM_WRITTEN is nonzero if the block was actually referenced
88 in the generated assembly. */
89 DEFTREECODE (BLOCK, "block", 'b', 0)
91 /* Each data type is represented by a tree node whose code is one of
93 /* Each node that represents a data type has a component TYPE_SIZE
94 containing a tree that is an expression for the size in bits.
95 The TYPE_MODE contains the machine mode for values of this type.
96 The TYPE_POINTER_TO field contains a type for a pointer to this type,
97 or zero if no such has been created yet.
98 The TYPE_NEXT_VARIANT field is used to chain together types
99 that are variants made by type modifiers such as "const" and "volatile".
100 The TYPE_MAIN_VARIANT field, in any member of such a chain,
101 points to the start of the chain.
102 The TYPE_NONCOPIED_PARTS field is a list specifying which parts
103 of an object of this type should *not* be copied by assignment.
104 The TREE_VALUE of each is a FIELD_DECL that should not be
105 copied. The TREE_PURPOSE is an initial value for that field when
106 an object of this type is initialized via an INIT_EXPR. It may
107 be NULL if no special value is required. Even the things in this
108 list are copied if the right-hand side of an assignment is known
109 to be a complete object (rather than being, perhaps, a subobject
110 of some other object.) The determination of what constitutes a
111 complete object is done by fixed_type_p.
112 The TYPE_NAME field contains info on the name used in the program
113 for this type (for GDB symbol table output). It is either a
114 TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
115 in the case of structs, unions or enums that are known with a tag,
116 or zero for types that have no special name.
117 The TYPE_CONTEXT for any sort of type which could have a name or
118 which could have named members (e.g. tagged types in C/C++) will
119 point to the node which represents the scope of the given type, or
120 will be NULL_TREE if the type has "file scope". For most types, this
121 will point to a BLOCK node or a FUNCTION_DECL node, but it could also
122 point to a FUNCTION_TYPE node (for types whose scope is limited to the
123 formal parameter list of some function type specification) or it
124 could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
125 (for C++ "member" types).
126 For non-tagged-types, TYPE_CONTEXT need not be set to anything in
127 particular, since any type which is of some type category (e.g.
128 an array type or a function type) which cannot either have a name
129 itself or have named members doesn't really have a "scope" per se.
130 The TREE_CHAIN field is used as a forward-references to names for
131 ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
134 DEFTREECODE (VOID_TYPE, "void_type", 't', 0) /* The void type in C */
136 /* Integer types in all languages, including char in C.
137 Also used for sub-ranges of other discrete types.
138 Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
139 and TYPE_PRECISION (number of bits used by this type).
140 In the case of a subrange type in Pascal, the TREE_TYPE
141 of this will point at the supertype (another INTEGER_TYPE,
142 or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
143 Otherwise, the TREE_TYPE is zero. */
144 DEFTREECODE (INTEGER_TYPE, "integer_type", 't', 0)
146 /* C's float and double. Different floating types are distinguished
147 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
148 DEFTREECODE (REAL_TYPE, "real_type", 't', 0)
150 /* Complex number types. The TREE_TYPE field is the data type
151 of the real and imaginary parts. */
152 DEFTREECODE (COMPLEX_TYPE, "complex_type", 't', 0)
154 /* Vector types. The TREE_TYPE field is the data type of the vector
156 DEFTREECODE (VECTOR_TYPE, "vector_type", 't', 0)
158 /* C enums. The type node looks just like an INTEGER_TYPE node.
159 The symbols for the values of the enum type are defined by
160 CONST_DECL nodes, but the type does not point to them;
161 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
162 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
163 /* A forward reference `enum foo' when no enum named foo is defined yet
164 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
165 the TYPE_NAME field. If the type is later defined, the normal
166 fields are filled in.
167 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
168 treated similarly. */
169 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", 't', 0)
171 /* Pascal's boolean type (true or false are the only values);
172 no special fields needed. */
173 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", 't', 0)
175 /* CHAR in Pascal; not used in C.
176 No special fields needed. */
177 DEFTREECODE (CHAR_TYPE, "char_type", 't', 0)
179 /* All pointer-to-x types have code POINTER_TYPE.
180 The TREE_TYPE points to the node for the type pointed to. */
181 DEFTREECODE (POINTER_TYPE, "pointer_type", 't', 0)
183 /* An offset is a pointer relative to an object.
184 The TREE_TYPE field is the type of the object at the offset.
185 The TYPE_OFFSET_BASETYPE points to the node for the type of object
186 that the offset is relative to. */
187 DEFTREECODE (OFFSET_TYPE, "offset_type", 't', 0)
189 /* A reference is like a pointer except that it is coerced
190 automatically to the value it points to. Used in C++. */
191 DEFTREECODE (REFERENCE_TYPE, "reference_type", 't', 0)
193 /* METHOD_TYPE is the type of a function which takes an extra first
194 argument for "self", which is not present in the declared argument list.
195 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
196 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
197 includes the hidden argument for "self". */
198 DEFTREECODE (METHOD_TYPE, "method_type", 't', 0)
200 /* Used for Pascal; details not determined right now. */
201 DEFTREECODE (FILE_TYPE, "file_type", 't', 0)
203 /* Types of arrays. Special fields:
204 TREE_TYPE Type of an array element.
205 TYPE_DOMAIN Type to index by.
206 Its range of values specifies the array length.
207 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
208 and holds the type to coerce a value of that array type to in C.
209 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
210 in languages (such as Chill) that make a distinction. */
211 /* Array types in C or Pascal */
212 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
214 /* Types of sets for Pascal. Special fields are the same as
215 in an array type. The target type is always a boolean type.
216 Used for both bitstrings and powersets in Chill;
217 TYPE_STRING_FLAG indicates a bitstring. */
218 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
220 /* Struct in C, or record in Pascal. */
222 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
223 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
224 types and enumerators.
225 A few may need to be added for Pascal. */
226 /* See the comment above, before ENUMERAL_TYPE, for how
227 forward references to struct tags are handled in C. */
228 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
230 /* Union in C. Like a struct, except that the offsets of the fields
232 /* See the comment above, before ENUMERAL_TYPE, for how
233 forward references to union tags are handled in C. */
234 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
236 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
237 in each FIELD_DECL determine what the union contains. The first
238 field whose DECL_QUALIFIER expression is true is deemed to occupy
240 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
242 /* Type of functions. Special fields:
243 TREE_TYPE type of value returned.
244 TYPE_ARG_TYPES list of types of arguments expected.
245 this list is made of TREE_LIST nodes.
246 Types of "Procedures" in languages where they are different from functions
247 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
248 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
250 /* This is a language-specific kind of type.
251 Its meaning is defined by the language front end.
252 layout_type does not know how to lay this out,
253 so the front-end must do so manually. */
254 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
258 /* First, the constants. */
260 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
261 32 bits each, giving us a 64 bit constant capability.
262 Note: constants of type char in Pascal are INTEGER_CST,
263 and so are pointer constants such as nil in Pascal or NULL in C.
264 `(int *) 1' in C also results in an INTEGER_CST. */
265 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 0)
267 /* Contents are in TREE_REAL_CST field. */
268 DEFTREECODE (REAL_CST, "real_cst", 'c', 0)
270 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
271 whose contents are other constant nodes. */
272 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 0)
274 /* Contents are in TREE_VECTOR_CST_ELTS field. */
275 DEFTREECODE (VECTOR_CST, "vector_cst", 'c', 0)
277 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields. */
278 DEFTREECODE (STRING_CST, "string_cst", 'c', 0)
280 /* Declarations. All references to names are represented as ..._DECL
281 nodes. The decls in one binding context are chained through the
282 TREE_CHAIN field. Each DECL has a DECL_NAME field which contains
283 an IDENTIFIER_NODE. (Some decls, most often labels, may have zero
284 as the DECL_NAME). DECL_CONTEXT points to the node representing
285 the context in which this declaration has its scope. For
286 FIELD_DECLs, this is the RECORD_TYPE, UNION_TYPE, or
287 QUAL_UNION_TYPE node that the field is a member of. For VAR_DECL,
288 PARM_DECL, FUNCTION_DECL, LABEL_DECL, and CONST_DECL nodes, this
289 points to either the FUNCTION_DECL for the containing function, the
290 RECORD_TYPE or UNION_TYPE for the containing type, or NULL_TREE or
291 a TRANSLATION_UNIT_DECL if the given decl has "file scope".
292 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
293 ..._DECL node of which this decl is an (inlined or template expanded)
295 The TREE_TYPE field holds the data type of the object, when relevant.
296 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
297 contents are the type whose name is being declared.
298 The DECL_ALIGN, DECL_SIZE,
299 and DECL_MODE fields exist in decl nodes just as in type nodes.
300 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
302 DECL_FIELD_BIT_OFFSET holds an integer number of bits offset for
303 the location. DECL_VOFFSET holds an expression for a variable
304 offset; it is to be multiplied by DECL_VOFFSET_UNIT (an integer).
305 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
307 DECL_INITIAL holds the value to initialize a variable to,
308 or the value of a constant. For a function, it holds the body
309 (a node of type BLOCK representing the function's binding contour
310 and whose body contains the function's statements.) For a LABEL_DECL
311 in C, it is a flag, nonzero if the label's definition has been seen.
313 PARM_DECLs use a special field:
314 DECL_ARG_TYPE is the type in which the argument is actually
315 passed, which may be different from its type within the function.
317 FUNCTION_DECLs use four special fields:
318 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
319 DECL_RESULT holds a RESULT_DECL node for the value of a function,
320 or it is 0 for a function that returns no value.
321 (C functions returning void have zero here.)
322 The TREE_TYPE field is the type in which the result is actually
323 returned. This is usually the same as the return type of the
324 FUNCTION_DECL, but it may be a wider integer type because of
326 DECL_FUNCTION_CODE is a code number that is nonzero for
327 built-in functions. Its value is an enum built_in_function
328 that says which built-in function it is.
330 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
331 holds a line number. In some cases these can be the location of
332 a reference, if no definition has been seen.
334 DECL_ABSTRACT is nonzero if the decl represents an abstract instance
335 of a decl (i.e. one which is nested within an abstract instance of a
338 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
339 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
340 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
341 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
342 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
343 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
344 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
345 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
347 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
348 _DECLs, providing a hierarchy of names. */
349 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
351 /* A translation unit. This is not technically a declaration, since it
352 can't be looked up, but it's close enough. */
353 DEFTREECODE (TRANSLATION_UNIT_DECL, "translation_unit_decl", 'd', 0)
355 /* References to storage. */
357 /* Value is structure or union component.
358 Operand 0 is the structure or union (an expression);
359 operand 1 is the field (a node of type FIELD_DECL). */
360 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
362 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
363 except the position is given explicitly rather than via a FIELD_DECL.
364 Operand 0 is the structure or union expression;
365 operand 1 is a tree giving the number of bits being referenced;
366 operand 2 is a tree giving the position of the first referenced bit.
367 The field can be either a signed or unsigned field;
368 TREE_UNSIGNED says which. */
369 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
371 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
372 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
374 /* Pascal `^` on a file. One operand, an expression for the file. */
375 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
378 Operand 0 is the array; operand 1 is a (single) array index. */
379 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
381 /* Likewise, except that the result is a range ("slice") of the array. The
382 starting index of the resulting array is taken from operand 1 and the size
383 of the range is taken from the type of the expression. */
384 DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", 'r', 2)
386 /* Vtable indexing. Carries data useful for emitting information
387 for vtable garbage collection.
388 Operand 0: an array_ref (or equivalent expression)
389 Operand 1: the vtable base (must be a var_decl)
390 Operand 2: index into vtable (must be an integer_cst). */
391 DEFTREECODE (VTABLE_REF, "vtable_ref", 'r', 3)
393 /* Constructor: return an aggregate value made from specified components.
394 In C, this is used only for structure and array initializers.
395 Also used for SET_TYPE in Chill (and potentially Pascal).
396 The operand is a list of component values made out of a chain of
400 The TREE_PURPOSE of each node is the corresponding index.
401 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
402 one for each index in the range. (If the corresponding TREE_VALUE
403 has side-effects, they are evaluated once for each element. Wrap the
404 value in a SAVE_EXPR if you want to evaluate side effects only once.)
406 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
407 The TREE_PURPOSE of each node is a FIELD_DECL.
410 The TREE_VALUE specifies a value (index) in the set that is true.
411 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
412 range of true values. Elements not listed are false (not in the set). */
413 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 1)
415 /* The expression types are mostly straightforward, with the fourth argument
416 of DEFTREECODE saying how many operands there are.
417 Unless otherwise specified, the operands are expressions and the
418 types of all the operands and the expression must all be the same. */
420 /* Contains two expressions to compute, one followed by the other.
421 the first value is ignored. The second one's value is used. The
422 type of the first expression need not agree with the other types. */
423 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
425 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
426 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
428 /* Initialization expression. Operand 0 is the variable to initialize;
429 Operand 1 is the initializer. */
430 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
432 /* For TARGET_EXPR, operand 0 is the target of an initialization,
433 operand 1 is the initializer for the target,
434 and operand 2 is the cleanup for this node, if any.
435 and operand 3 is the saved initializer after this node has been
436 expanded once, this is so we can re-expand the tree later. */
437 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
439 /* Conditional expression ( ... ? ... : ... in C).
440 Operand 0 is the condition.
441 Operand 1 is the then-value.
442 Operand 2 is the else-value.
443 Operand 0 may be of any type.
444 Operand 1 must have the same type as the entire expression, unless
445 it unconditionally throws an exception, in which case it should
446 have VOID_TYPE. The same constraints apply to operand 2. */
447 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
449 /* Declare local variables, including making RTL and allocating space.
450 Operand 0 is a chain of VAR_DECL nodes for the variables.
451 Operand 1 is the body, the expression to be computed using
452 the variables. The value of operand 1 becomes that of the BIND_EXPR.
453 Operand 2 is the BLOCK that corresponds to these bindings
454 for debugging purposes. If this BIND_EXPR is actually expanded,
455 that sets the TREE_USED flag in the BLOCK.
457 The BIND_EXPR is not responsible for informing parsers
458 about these variables. If the body is coming from the input file,
459 then the code that creates the BIND_EXPR is also responsible for
460 informing the parser of the variables.
462 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
463 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
464 If the BIND_EXPR should be output for debugging but will not be expanded,
465 set the TREE_USED flag by hand.
467 In order for the BIND_EXPR to be known at all, the code that creates it
468 must also install it as a subblock in the tree of BLOCK
469 nodes for the function. */
470 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
472 /* Function call. Operand 0 is the function.
473 Operand 1 is the argument list, a list of expressions
474 made out of a chain of TREE_LIST nodes. */
475 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 2)
477 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
478 Operand 1 is the expression for "self".
479 Operand 2 is the list of explicit arguments. */
480 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
482 /* Specify a value to compute along with its corresponding cleanup.
483 Operand 0 argument is an expression whose value needs a cleanup.
484 Operand 1 is the cleanup expression for the object.
485 Operand 2 is an RTL_EXPR which will eventually represent that value.
486 The RTL_EXPR is used in this expression, which is how the expression
487 manages to act on the proper value.
488 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
489 it exists, otherwise it is the responsibility of the caller to manually
490 call expand_start_target_temps/expand_end_target_temps, as needed.
492 This differs from TRY_CATCH_EXPR in that operand 2 is always
493 evaluated when an exception isn't thrown when cleanups are run. */
494 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
496 /* Specify a cleanup point.
497 Operand 0 is an expression that may have cleanups. If it does, those
498 cleanups are executed after the expression is expanded.
500 Note that if the expression is a reference to storage, it is forced out
501 of memory before the cleanups are run. This is necessary to handle
502 cases where the cleanups modify the storage referenced; in the
503 expression 't.i', if 't' is a struct with an integer member 'i' and a
504 cleanup which modifies 'i', the value of the expression depends on
505 whether the cleanup is run before or after 't.i' is evaluated. When
506 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
507 the value of 't.i' must be forced out of memory.
509 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
510 BLKmode, because it will not be forced out of memory. */
511 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
513 /* The following two codes are used in languages that have types where
514 some field in an object of the type contains a value that is used in
515 the computation of another field's offset or size and/or the size of
516 the type. The positions and/or sizes of fields can vary from object
517 to object of the same type.
519 Record types with discriminants in Ada or schema types in Pascal are
520 examples of such types. This mechanism is also used to create "fat
521 pointers" for unconstrained array types in Ada; the fat pointer is a
522 structure one of whose fields is a pointer to the actual array type
523 and the other field is a pointer to a template, which is a structure
524 containing the bounds of the array. The bounds in the type pointed
525 to by the first field in the fat pointer refer to the values in the
528 When you wish to construct such a type you need "self-references"
529 that allow you to reference the object having this type from the
530 TYPE node, i.e. without having a variable instantiating this type.
532 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
533 a node that will later be replaced with the object being referenced.
534 Its type is that of the object and selects which object to use from
535 a chain of references (see below). No other slots are used in the
538 For example, if your type FOO is a RECORD_TYPE with a field BAR,
539 and you need the value of <variable>.BAR to calculate TYPE_SIZE
540 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
541 what contains both the expression we wish to
542 evaluate and an expression within which the object may be found.
543 The latter expression is the object itself in the simple case of an
544 Ada record with discriminant, but it can be the array in the case of
545 an unconstrained array.
547 In the latter case, we need the fat pointer, because the bounds of
548 the array can only be accessed from it. However, we rely here on the
549 fact that the expression for the array contains the dereference of
550 the fat pointer that obtained the array pointer.
552 Accordingly, when looking for the object to substitute in place of
553 a PLACEHOLDER_EXPR, we look down the first operand of the expression
554 passed as the second operand to WITH_RECORD_EXPR until we find
555 something of the desired type or reach a constant. */
557 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
558 evaluating this expression. The type of this expression is used to
559 find the record to replace it. */
560 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
562 /* Provide an expression that references a record to be used in place
563 of a PLACEHOLDER_EXPR. The record to be used is the record within
564 operand 1 that has the same type as the PLACEHOLDER_EXPR in
566 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
568 /* Simple arithmetic. */
569 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
570 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
571 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
573 /* Division for integer result that rounds the quotient toward zero. */
574 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
576 /* Division for integer result that rounds the quotient toward infinity. */
577 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
579 /* Division for integer result that rounds toward minus infinity. */
580 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
582 /* Division for integer result that rounds toward nearest integer. */
583 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
585 /* Four kinds of remainder that go with the four kinds of division. */
586 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
587 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
588 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
589 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
591 /* Division for real result. */
592 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
594 /* Division which is not supposed to need rounding.
595 Used for pointer subtraction in C. */
596 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
598 /* Conversion of real to fixed point: four ways to round,
599 like the four ways to divide.
600 CONVERT_EXPR can also be used to convert a real to an integer,
601 and that is what is used in languages that do not have ways of
602 specifying which of these is wanted. Maybe these are not needed. */
603 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
604 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
605 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
606 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
608 /* Conversion of an integer to a real. */
609 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
611 /* Unary negation. */
612 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
614 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
615 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
617 /* Represents the absolute value of the operand.
619 An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
620 operand of the ABS_EXPR must have the same type. */
621 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
623 /* Bit scanning and counting. */
624 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
625 DEFTREECODE (CLZ_EXPR, "clz_expr", '1', 1)
626 DEFTREECODE (CTZ_EXPR, "ctz_expr", '1', 1)
627 DEFTREECODE (POPCOUNT_EXPR, "popcount_expr", '1', 1)
628 DEFTREECODE (PARITY_EXPR, "parity_expr", '1', 1)
630 /* Shift operations for shift and rotate.
631 Shift means logical shift if done on an
632 unsigned type, arithmetic shift if done on a signed type.
633 The second operand is the number of bits to
634 shift by; it need not be the same type as the first operand and result.
635 Note that the result is undefined if the second operand is larger
636 than the first operand's type size. */
637 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
638 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
639 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
640 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
642 /* Bitwise operations. Operands have same mode as result. */
643 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
644 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
645 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
646 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
647 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
649 /* ANDIF and ORIF allow the second operand not to be computed if the
650 value of the expression is determined from the first operand. AND,
651 OR, and XOR always compute the second operand whether its value is
652 needed or not (for side effects). The operand may have
653 BOOLEAN_TYPE or INTEGER_TYPE. In either case, the argument will be
654 either zero or one. For example, a TRUTH_NOT_EXPR will never have
655 an INTEGER_TYPE VAR_DECL as its argument; instead, a NE_EXPR will be
656 used to compare the VAR_DECL to zero, thereby obtaining a node with
657 value zero or one. */
658 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
659 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
660 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
661 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
662 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
663 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
665 /* Relational operators.
666 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
667 The others are allowed only for integer (or pointer or enumeral)
669 In all cases the operands will have the same type,
670 and the value is always the type used by the language for booleans. */
671 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
672 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
673 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
674 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
675 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
676 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
678 /* Additional relational operators for floating point unordered. */
679 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", '<', 2)
680 DEFTREECODE (ORDERED_EXPR, "ordered_expr", '<', 2)
682 /* These are equivalent to unordered or ... */
683 DEFTREECODE (UNLT_EXPR, "unlt_expr", '<', 2)
684 DEFTREECODE (UNLE_EXPR, "unle_expr", '<', 2)
685 DEFTREECODE (UNGT_EXPR, "ungt_expr", '<', 2)
686 DEFTREECODE (UNGE_EXPR, "unge_expr", '<', 2)
687 DEFTREECODE (UNEQ_EXPR, "uneq_expr", '<', 2)
689 /* Operations for Pascal sets. Not used now. */
690 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
691 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
692 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
693 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
695 /* Represents a conversion of type of a value.
696 All conversions, including implicit ones, must be
697 represented by CONVERT_EXPR or NOP_EXPR nodes. */
698 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
700 /* Represents a conversion expected to require no code to be generated. */
701 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
703 /* Value is same as argument, but guaranteed not an lvalue. */
704 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
706 /* Represents viewing something of one type as being of a second type.
707 This corresponds to an "Unchecked Conversion" in Ada and roughly to
708 the idiom *(type2 *)&X in C. The only operand is the value to be
709 viewed as being of another type. It is undefined if the type of the
710 input and of the expression have different sizes.
712 This code may also be used within the LHS of a MODIFY_EXPR, in which
713 case no actual data motion may occur. TREE_ADDRESSABLE will be set in
714 this case and GCC must abort if it could not do the operation without
716 DEFTREECODE (VIEW_CONVERT_EXPR, "view_convert_expr", '1', 1)
718 /* Represents something we computed once and will use multiple times.
719 First operand is that expression. Second is the function decl
720 in which the SAVE_EXPR was created. The third operand is the RTL,
721 nonzero only after the expression has been computed. */
722 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
724 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
725 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
726 CALL_EXPRs and RTL_EXPRs, that are protected
727 from being evaluated more than once should be reset so that a new
728 expand_expr call of this expr will cause those to be re-evaluated.
729 This is useful when we want to reuse a tree in different places,
730 but where we must re-expand. */
731 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
733 /* Represents something whose RTL has already been expanded as a
734 sequence which should be emitted when this expression is expanded.
735 The first operand is the RTL to emit. It is the first of a chain
736 of insns. The second is the RTL expression for the result. Any
737 temporaries created during the building of the RTL_EXPR can be
738 reused once the RTL_EXPR has been expanded, with the exception of
740 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
742 /* & in C. Value is the address at which the operand's value resides.
743 Operand may have any mode. Result mode is Pmode. */
744 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
746 /* Non-lvalue reference or pointer to an object. */
747 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
749 /* Operand is a function constant; result is a function variable value
750 of type EPmode. Used only for languages that need static chains. */
751 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
753 /* Operand0 is a function constant; result is part N of a function
754 descriptor of type ptr_mode. */
755 DEFTREECODE (FDESC_EXPR, "fdesc_expr", 'e', 2)
757 /* Given two real or integer operands of the same type,
758 returns a complex value of the corresponding complex type. */
759 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
761 /* Complex conjugate of operand. Used only on complex types. */
762 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
764 /* Used only on an operand of complex type, these return
765 a value of the corresponding component type. */
766 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
767 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
769 /* Nodes for ++ and -- in C.
770 The second arg is how much to increment or decrement by.
771 For a pointer, it would be the size of the object pointed to. */
772 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
773 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
774 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
775 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
777 /* Used to implement `va_arg'. */
778 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
780 /* Evaluate operand 1. If and only if an exception is thrown during
781 the evaluation of operand 1, evaluate operand 2.
783 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
784 evaluated unless an exception is throw. */
785 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
787 /* Evaluate the first operand.
788 The second operand is a cleanup expression which is evaluated
789 on any exit (normal, exception, or jump out) from this expression. */
790 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
792 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
793 (Specifically, it is created by expand_expr, not front-ends.)
794 Operand 0 is the rtx for the start of the subroutine we need to call.
795 Operand 1 is the rtx for a variable in which to store the address
796 of where the subroutine should return to. */
797 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
799 /* These types of expressions have no useful value,
800 and always have side effects. */
802 /* A label definition, encapsulated as a statement.
803 Operand 0 is the LABEL_DECL node for the label that appears here.
804 The type should be void and the value should be ignored. */
805 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
807 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
808 The type should be void and the value should be ignored. */
809 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
811 /* RETURN. Evaluates operand 0, then returns from the current function.
812 Presumably that operand is an assignment that stores into the
813 RESULT_DECL that hold the value to be returned.
814 The operand may be null.
815 The type should be void and the value should be ignored. */
816 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
818 /* Exit the inner most loop conditionally. Operand 0 is the condition.
819 The type should be void and the value should be ignored. */
820 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
822 /* A loop. Operand 0 is the body of the loop.
823 It must contain an EXIT_EXPR or is an infinite loop.
824 The type should be void and the value should be ignored. */
825 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
827 /* A labeled block. Operand 0 is the label that will be generated to
828 mark the end of the block.
829 Operand 1 is the labeled block body. */
830 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
832 /* Exit a labeled block, possibly returning a value. Operand 0 is a
833 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
835 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
837 /* Annotates a tree node (usually an expression) with source location
838 information: a file name (EXPR_WFL_FILENAME); a line number
839 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
840 expanded as the contained node (EXPR_WFL_NODE); a line note should
841 be emitted first if EXPR_WFL_EMIT_LINE_NOTE.
842 The third operand is only used in the Java front-end, and will
843 eventually be removed. */
844 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 3)
846 /* Switch expression.
847 Operand 0 is the expression used to perform the branch,
848 Operand 1 contains the case values. The way they're organized is
849 front-end implementation defined. */
850 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
852 /* The exception object from the runtime. */
853 DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", 'e', 0)
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