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, 2004
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 '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 "statement" expressions, which have side-effects,
34 but usually no interesting value.
35 'e' for codes for other kinds of expressions. */
37 /* For `r', `e', `<', `1', `2', and `s' nodes, which use struct
38 tree_exp, the 4th element is the number of argument slots to
39 allocate. This determines the size of the tree node object.
40 Other nodes use different structures, and the size is determined
41 by the tree_union member structure; the 4th element should be
42 zero. Languages that define language-specific 'x' or 'c' codes
43 must define the tree_size langhook to say how big they are. */
45 /* Any erroneous construct is parsed into a node of this type.
46 This type of node is accepted without complaint in all contexts
47 by later parsing activities, to avoid multiple error messages
49 No fields in these nodes are used except the TREE_CODE. */
50 DEFTREECODE (ERROR_MARK, "error_mark", 'x', 0)
52 /* Used to represent a name (such as, in the DECL_NAME of a decl node).
53 Internally it looks like a STRING_CST node.
54 There is only one IDENTIFIER_NODE ever made for any particular name.
55 Use `get_identifier' to get it (or create it, the first time). */
56 DEFTREECODE (IDENTIFIER_NODE, "identifier_node", 'x', 0)
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', 0)
65 /* These nodes contain an array of tree nodes. */
66 DEFTREECODE (TREE_VEC, "tree_vec", 'x', 0)
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.
72 For a block which represents the outermost scope of a function, it
73 points to the FUNCTION_DECL node.
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.
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 nonzero if the block represents an abstract
84 instance of a block (i.e. one which is nested within an abstract
85 instance of an inline function).
86 TREE_ASM_WRITTEN is nonzero if the block was actually referenced
87 in the generated assembly. */
88 DEFTREECODE (BLOCK, "block", 'x', 0)
90 /* Each data type is represented by a tree node whose code is one of
92 /* Each node that represents a data type has a component TYPE_SIZE
93 containing a tree that is an expression for the size in bits.
94 The TYPE_MODE contains the machine mode for values of this type.
95 The TYPE_POINTER_TO field contains a type for a pointer to this type,
96 or zero if no such has been created yet.
97 The TYPE_NEXT_VARIANT field is used to chain together types
98 that are variants made by type modifiers such as "const" and "volatile".
99 The TYPE_MAIN_VARIANT field, in any member of such a chain,
100 points to the start of the chain.
101 The TYPE_NONCOPIED_PARTS field is a list specifying which parts
102 of an object of this type should *not* be copied by assignment.
103 The TREE_VALUE of each is a FIELD_DECL that should not be
104 copied. The TREE_PURPOSE is an initial value for that field when
105 an object of this type is initialized via an INIT_EXPR. It may
106 be NULL if no special value is required. Even the things in this
107 list are copied if the right-hand side of an assignment is known
108 to be a complete object (rather than being, perhaps, a subobject
109 of some other object.) The determination of what constitutes a
110 complete object is done by fixed_type_p.
111 The TYPE_NAME field contains info on the name used in the program
112 for this type (for GDB symbol table output). It is either a
113 TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
114 in the case of structs, unions or enums that are known with a tag,
115 or zero for types that have no special name.
116 The TYPE_CONTEXT for any sort of type which could have a name or
117 which could have named members (e.g. tagged types in C/C++) will
118 point to the node which represents the scope of the given type, or
119 will be NULL_TREE if the type has "file scope". For most types, this
120 will point to a BLOCK node or a FUNCTION_DECL node, but it could also
121 point to a FUNCTION_TYPE node (for types whose scope is limited to the
122 formal parameter list of some function type specification) or it
123 could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
124 (for C++ "member" types).
125 For non-tagged-types, TYPE_CONTEXT need not be set to anything in
126 particular, since any type which is of some type category (e.g.
127 an array type or a function type) which cannot either have a name
128 itself or have named members doesn't really have a "scope" per se.
129 The TREE_CHAIN field is used as a forward-references to names for
130 ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
133 DEFTREECODE (VOID_TYPE, "void_type", 't', 0) /* The void type in C */
135 /* Integer types in all languages, including char in C.
136 Also used for sub-ranges of other discrete types.
137 Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
138 and TYPE_PRECISION (number of bits used by this type).
139 In the case of a subrange type in Pascal, the TREE_TYPE
140 of this will point at the supertype (another INTEGER_TYPE,
141 or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
142 Otherwise, the TREE_TYPE is zero. */
143 DEFTREECODE (INTEGER_TYPE, "integer_type", 't', 0)
145 /* C's float and double. Different floating types are distinguished
146 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
147 DEFTREECODE (REAL_TYPE, "real_type", 't', 0)
149 /* Complex number types. The TREE_TYPE field is the data type
150 of the real and imaginary parts. */
151 DEFTREECODE (COMPLEX_TYPE, "complex_type", 't', 0)
153 /* Vector types. The TREE_TYPE field is the data type of the vector
154 elements. The TYPE_PRECISION field is the number of subparts of
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. INTEGER_CST
262 nodes can be shared, and therefore should be considered read only.
263 They should be copied, before setting a flag such as
264 TREE_OVERFLOW. If an INTEGER_CST has TREE_OVERFLOW or
265 TREE_CONSTANT_OVERFLOW already set, it is known to be unique.
266 INTEGER_CST nodes are created for the integral types, for pointer
267 types and for vector and float types in some circumstances. */
268 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 0)
270 /* Contents are in TREE_REAL_CST field. */
271 DEFTREECODE (REAL_CST, "real_cst", 'c', 0)
273 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
274 whose contents are other constant nodes. */
275 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 0)
277 /* Contents are in TREE_VECTOR_CST_ELTS field. */
278 DEFTREECODE (VECTOR_CST, "vector_cst", 'c', 0)
280 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields. */
281 DEFTREECODE (STRING_CST, "string_cst", 'c', 0)
283 /* Declarations. All references to names are represented as ..._DECL
284 nodes. The decls in one binding context are chained through the
285 TREE_CHAIN field. Each DECL has a DECL_NAME field which contains
286 an IDENTIFIER_NODE. (Some decls, most often labels, may have zero
287 as the DECL_NAME). DECL_CONTEXT points to the node representing
288 the context in which this declaration has its scope. For
289 FIELD_DECLs, this is the RECORD_TYPE, UNION_TYPE, or
290 QUAL_UNION_TYPE node that the field is a member of. For VAR_DECL,
291 PARM_DECL, FUNCTION_DECL, LABEL_DECL, and CONST_DECL nodes, this
292 points to either the FUNCTION_DECL for the containing function, the
293 RECORD_TYPE or UNION_TYPE for the containing type, or NULL_TREE or
294 a TRANSLATION_UNIT_DECL if the given decl has "file scope".
295 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
296 ..._DECL node of which this decl is an (inlined or template expanded)
298 The TREE_TYPE field holds the data type of the object, when relevant.
299 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
300 contents are the type whose name is being declared.
301 The DECL_ALIGN, DECL_SIZE,
302 and DECL_MODE fields exist in decl nodes just as in type nodes.
303 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
305 DECL_FIELD_BIT_OFFSET holds an integer number of bits offset for
306 the location. DECL_VOFFSET holds an expression for a variable
307 offset; it is to be multiplied by DECL_VOFFSET_UNIT (an integer).
308 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
310 DECL_INITIAL holds the value to initialize a variable to,
311 or the value of a constant. For a function, it holds the body
312 (a node of type BLOCK representing the function's binding contour
313 and whose body contains the function's statements.) For a LABEL_DECL
314 in C, it is a flag, nonzero if the label's definition has been seen.
316 PARM_DECLs use a special field:
317 DECL_ARG_TYPE is the type in which the argument is actually
318 passed, which may be different from its type within the function.
320 FUNCTION_DECLs use four special fields:
321 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
322 DECL_RESULT holds a RESULT_DECL node for the value of a function,
323 or it is 0 for a function that returns no value.
324 (C functions returning void have zero here.)
325 The TREE_TYPE field is the type in which the result is actually
326 returned. This is usually the same as the return type of the
327 FUNCTION_DECL, but it may be a wider integer type because of
329 DECL_FUNCTION_CODE is a code number that is nonzero for
330 built-in functions. Its value is an enum built_in_function
331 that says which built-in function it is.
333 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
334 holds a line number. In some cases these can be the location of
335 a reference, if no definition has been seen.
337 DECL_ABSTRACT is nonzero if the decl represents an abstract instance
338 of a decl (i.e. one which is nested within an abstract instance of a
341 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
342 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
343 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
344 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
345 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
346 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
347 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
348 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
350 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
351 _DECLs, providing a hierarchy of names. */
352 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
354 /* A translation unit. This is not technically a declaration, since it
355 can't be looked up, but it's close enough. */
356 DEFTREECODE (TRANSLATION_UNIT_DECL, "translation_unit_decl", 'd', 0)
358 /* References to storage. */
360 /* Value is structure or union component.
361 Operand 0 is the structure or union (an expression).
362 Operand 1 is the field (a node of type FIELD_DECL).
363 Operand 2, if present, is the value of DECL_FIELD_OFFSET, measured
364 in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT. */
365 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 3)
367 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
368 except the position is given explicitly rather than via a FIELD_DECL.
369 Operand 0 is the structure or union expression;
370 operand 1 is a tree giving the number of bits being referenced;
371 operand 2 is a tree giving the position of the first referenced bit.
372 The field can be either a signed or unsigned field;
373 BIT_FIELD_REF_UNSIGNED says which. */
374 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
376 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
377 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
380 Operand 0 is the array; operand 1 is a (single) array index.
381 Operand 2, if present, is a copy of TYPE_MIN_VALUE of the index.
382 Operand 3, if present, is the element size, measured in units of
383 the alignment of the element type. */
384 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 4)
386 /* Likewise, except that the result is a range ("slice") of the array. The
387 starting index of the resulting array is taken from operand 1 and the size
388 of the range is taken from the type of the expression. */
389 DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", 'r', 4)
391 /* Used to represent lookup of runtime type dependent data. Often this is
392 a reference to a vtable, but it needn't be. Operands are:
393 OBJ_TYPE_REF_EXPR: An expression that evaluates the value to use.
394 OBJ_TYPE_REF_OBJECT: Is the object on whose behalf the lookup is
395 being performed. Through this the optimizers may be able to statically
396 determine the dynamic type of the object.
397 OBJ_TYPE_REF_TOKEN: Something front-end specific used to resolve the
398 reference to something simpler, usually to the address of a DECL.
399 Never touched by the middle-end. Good choices would be either an
400 identifier or a vtable index. */
401 DEFTREECODE (OBJ_TYPE_REF, "obj_type_ref", 'e', 3)
403 /* The exception object from the runtime. */
404 DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", 'e', 0)
406 /* The filter object from the runtime. */
407 DEFTREECODE (FILTER_EXPR, "filter_expr", 'e', 0)
409 /* Constructor: return an aggregate value made from specified components.
410 In C, this is used only for structure and array initializers.
411 Also used for SET_TYPE in Chill (and potentially Pascal).
412 The operand is a list of component values made out of a chain of
416 The TREE_PURPOSE of each node is the corresponding index.
417 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
418 one for each index in the range. (If the corresponding TREE_VALUE
419 has side-effects, they are evaluated once for each element. Wrap the
420 value in a SAVE_EXPR if you want to evaluate side effects only once.)
422 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
423 The TREE_PURPOSE of each node is a FIELD_DECL.
426 The TREE_VALUE specifies a value (index) in the set that is true.
427 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
428 range of true values. Elements not listed are false (not in the set). */
429 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 1)
431 /* The expression types are mostly straightforward, with the fourth argument
432 of DEFTREECODE saying how many operands there are.
433 Unless otherwise specified, the operands are expressions and the
434 types of all the operands and the expression must all be the same. */
436 /* Contains two expressions to compute, one followed by the other.
437 the first value is ignored. The second one's value is used. The
438 type of the first expression need not agree with the other types. */
439 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
441 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
442 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
444 /* Initialization expression. Operand 0 is the variable to initialize;
445 Operand 1 is the initializer. */
446 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
448 /* For TARGET_EXPR, operand 0 is the target of an initialization,
449 operand 1 is the initializer for the target, which may be void
450 if simply expanding it initializes the target.
451 operand 2 is the cleanup for this node, if any.
452 operand 3 is the saved initializer after this node has been
453 expanded once; this is so we can re-expand the tree later. */
454 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
456 /* Conditional expression ( ... ? ... : ... in C).
457 Operand 0 is the condition.
458 Operand 1 is the then-value.
459 Operand 2 is the else-value.
460 Operand 0 may be of any type.
461 Operand 1 must have the same type as the entire expression, unless
462 it unconditionally throws an exception, in which case it should
463 have VOID_TYPE. The same constraints apply to operand 2. */
464 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
466 /* Declare local variables, including making RTL and allocating space.
467 BIND_EXPR_VARS is a chain of VAR_DECL nodes for the variables.
468 BIND_EXPR_BODY is the body, the expression to be computed using
469 the variables. The value of operand 1 becomes that of the BIND_EXPR.
470 BIND_EXPR_BLOCK is the BLOCK that corresponds to these bindings
471 for debugging purposes. If this BIND_EXPR is actually expanded,
472 that sets the TREE_USED flag in the BLOCK.
474 The BIND_EXPR is not responsible for informing parsers
475 about these variables. If the body is coming from the input file,
476 then the code that creates the BIND_EXPR is also responsible for
477 informing the parser of the variables.
479 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
480 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
481 If the BIND_EXPR should be output for debugging but will not be expanded,
482 set the TREE_USED flag by hand.
484 In order for the BIND_EXPR to be known at all, the code that creates it
485 must also install it as a subblock in the tree of BLOCK
486 nodes for the function. */
487 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
489 /* A labeled block. Operand 0 is the label that will be generated to
490 mark the end of the block.
491 Operand 1 is the labeled block body. */
492 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
494 /* Function call. Operand 0 is the function.
495 Operand 1 is the argument list, a list of expressions
496 made out of a chain of TREE_LIST nodes.
497 Operand 2 is the static chain argument, or NULL. */
498 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 3)
500 /* Specify a value to compute along with its corresponding cleanup.
501 Operand 0 is the cleanup expression.
502 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR,
503 which must exist. This differs from TRY_CATCH_EXPR in that operand 1
504 is always evaluated when cleanups are run. */
505 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 1)
507 /* Specify a cleanup point.
508 Operand 0 is an expression that may have cleanups. If it does, those
509 cleanups are executed after the expression is expanded.
511 Note that if the expression is a reference to storage, it is forced out
512 of memory before the cleanups are run. This is necessary to handle
513 cases where the cleanups modify the storage referenced; in the
514 expression 't.i', if 't' is a struct with an integer member 'i' and a
515 cleanup which modifies 'i', the value of the expression depends on
516 whether the cleanup is run before or after 't.i' is evaluated. When
517 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
518 the value of 't.i' must be forced out of memory.
520 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
521 BLKmode, because it will not be forced out of memory. */
522 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
524 /* The following two codes are used in languages that have types where
525 some field in an object of the type contains a value that is used in
526 the computation of another field's offset or size and/or the size of
527 the type. The positions and/or sizes of fields can vary from object
528 to object of the same type or even for one and the same object within
531 Record types with discriminants in Ada or schema types in Pascal are
532 examples of such types. This mechanism is also used to create "fat
533 pointers" for unconstrained array types in Ada; the fat pointer is a
534 structure one of whose fields is a pointer to the actual array type
535 and the other field is a pointer to a template, which is a structure
536 containing the bounds of the array. The bounds in the type pointed
537 to by the first field in the fat pointer refer to the values in the
540 When you wish to construct such a type you need "self-references"
541 that allow you to reference the object having this type from the
542 TYPE node, i.e. without having a variable instantiating this type.
544 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
545 a node that will later be replaced with the object being referenced.
546 Its type is that of the object and selects which object to use from
547 a chain of references (see below). No other slots are used in the
550 For example, if your type FOO is a RECORD_TYPE with a field BAR,
551 and you need the value of <variable>.BAR to calculate TYPE_SIZE
552 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
553 whose TREE_TYPE is FOO. Then construct your COMPONENT_REF with
554 the PLACEHOLDER_EXPR as the first operand (which has the correct
555 type). Later, when the size is needed in the program, the back-end
556 will find this PLACEHOLDER_EXPR and generate code to calculate the
557 actual size at run-time. In the following, we describe how this
560 When we wish to evaluate a size or offset, we check whether it contains a
561 PLACEHOLDER_EXPR. If it does, we call substitute_placeholder_in_expr
562 passing both that tree and an expression within which the object may be
563 found. The latter expression is the object itself in the simple case of
564 an Ada record with discriminant, but it can be the array in the case of an
567 In the latter case, we need the fat pointer, because the bounds of
568 the array can only be accessed from it. However, we rely here on the
569 fact that the expression for the array contains the dereference of
570 the fat pointer that obtained the array pointer. */
572 /* Denotes a record to later be substituted before evaluating this expression.
573 The type of this expression is used to find the record to replace it. */
574 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
576 /* Simple arithmetic. */
577 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
578 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
579 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
581 /* Division for integer result that rounds the quotient toward zero. */
582 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
584 /* Division for integer result that rounds the quotient toward infinity. */
585 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
587 /* Division for integer result that rounds toward minus infinity. */
588 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
590 /* Division for integer result that rounds toward nearest integer. */
591 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
593 /* Four kinds of remainder that go with the four kinds of division. */
594 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
595 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
596 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
597 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
599 /* Division for real result. */
600 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
602 /* Division which is not supposed to need rounding.
603 Used for pointer subtraction in C. */
604 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
606 /* Conversion of real to fixed point: four ways to round,
607 like the four ways to divide.
608 CONVERT_EXPR can also be used to convert a real to an integer,
609 and that is what is used in languages that do not have ways of
610 specifying which of these is wanted. Maybe these are not needed. */
611 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
612 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
613 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
614 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
616 /* Conversion of an integer to a real. */
617 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
619 /* Unary negation. */
620 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
622 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
623 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
625 /* Represents the absolute value of the operand.
627 An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
628 operand of the ABS_EXPR must have the same type. */
629 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
631 /* Shift operations for shift and rotate.
632 Shift means logical shift if done on an
633 unsigned type, arithmetic shift if done on a signed type.
634 The second operand is the number of bits to
635 shift by; it need not be the same type as the first operand and result.
636 Note that the result is undefined if the second operand is larger
637 than the first operand's type size. */
638 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
639 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
640 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
641 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
643 /* Bitwise operations. Operands have same mode as result. */
644 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
645 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
646 DEFTREECODE (BIT_AND_EXPR, "bit_and_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 /* This is the reverse of uneq_expr. */
690 DEFTREECODE (LTGT_EXPR, "ltgt_expr", '<', 2)
692 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
694 /* Represents a conversion of type of a value.
695 All conversions, including implicit ones, must be
696 represented by CONVERT_EXPR or NOP_EXPR nodes. */
697 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
699 /* Represents a conversion expected to require no code to be generated. */
700 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
702 /* Value is same as argument, but guaranteed not an lvalue. */
703 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
705 /* Represents viewing something of one type as being of a second type.
706 This corresponds to an "Unchecked Conversion" in Ada and roughly to
707 the idiom *(type2 *)&X in C. The only operand is the value to be
708 viewed as being of another type. It is undefined if the type of the
709 input and of the expression have different sizes.
711 This code may also be used within the LHS of a MODIFY_EXPR, in which
712 case no actual data motion may occur. TREE_ADDRESSABLE will be set in
713 this case and GCC must abort if it could not do the operation without
715 DEFTREECODE (VIEW_CONVERT_EXPR, "view_convert_expr", 'r', 1)
717 /* Represents something we computed once and will use multiple times.
718 First operand is that expression. After it is evaluated once, it
719 will be replaced by the temporary variable that holds the value. */
720 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 1)
722 /* & in C. Value is the address at which the operand's value resides.
723 Operand may have any mode. Result mode is Pmode. */
724 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
726 /* Operand0 is a function constant; result is part N of a function
727 descriptor of type ptr_mode. */
728 DEFTREECODE (FDESC_EXPR, "fdesc_expr", 'e', 2)
730 /* Given two real or integer operands of the same type,
731 returns a complex value of the corresponding complex type. */
732 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
734 /* Complex conjugate of operand. Used only on complex types. */
735 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
737 /* Used only on an operand of complex type, these return
738 a value of the corresponding component type. */
739 DEFTREECODE (REALPART_EXPR, "realpart_expr", 'r', 1)
740 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", 'r', 1)
742 /* Nodes for ++ and -- in C.
743 The second arg is how much to increment or decrement by.
744 For a pointer, it would be the size of the object pointed to. */
745 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
746 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
747 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
748 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
750 /* Used to implement `va_arg'. */
751 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
753 /* Evaluate operand 1. If and only if an exception is thrown during
754 the evaluation of operand 1, evaluate operand 2.
756 This differs from TRY_FINALLY_EXPR in that operand 2 is not evaluated
757 on a normal or jump exit, only on an exception. */
758 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 's', 2)
760 /* Evaluate the first operand.
761 The second operand is a cleanup expression which is evaluated
762 on any exit (normal, exception, or jump out) from this expression. */
763 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 's', 2)
765 /* These types of expressions have no useful value,
766 and always have side effects. */
768 /* Used to represent a local declaration. The operand is DECL_EXPR_DECL. */
769 DEFTREECODE (DECL_EXPR, "decl_expr", 's', 1)
771 /* A label definition, encapsulated as a statement.
772 Operand 0 is the LABEL_DECL node for the label that appears here.
773 The type should be void and the value should be ignored. */
774 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
776 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
777 The type should be void and the value should be ignored. */
778 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
780 /* RETURN. Evaluates operand 0, then returns from the current function.
781 Presumably that operand is an assignment that stores into the
782 RESULT_DECL that hold the value to be returned.
783 The operand may be null.
784 The type should be void and the value should be ignored. */
785 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
787 /* Exit the inner most loop conditionally. Operand 0 is the condition.
788 The type should be void and the value should be ignored. */
789 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
791 /* A loop. Operand 0 is the body of the loop.
792 It must contain an EXIT_EXPR or is an infinite loop.
793 The type should be void and the value should be ignored. */
794 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
796 /* Exit a labeled block, possibly returning a value. Operand 0 is a
797 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
799 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 's', 2)
801 /* Switch expression.
803 TREE_TYPE is the original type of the condition, before any
804 language required type conversions. It may be NULL, in which case
805 the original type and final types are assumed to be the same.
807 Operand 0 is the expression used to perform the branch,
808 Operand 1 is the body of the switch, which probably contains
809 CASE_LABEL_EXPRs. It may also be NULL, in which case operand 2
811 Operand 2 is either NULL_TREE or a TREE_VEC of the CASE_LABEL_EXPRs
813 DEFTREECODE (SWITCH_EXPR, "switch_expr", 's', 3)
815 /* Used to represent a case label. The operands are CASE_LOW and
816 CASE_HIGH, respectively. If CASE_LOW is NULL_TREE, the label is a
817 'default' label. If CASE_HIGH is NULL_TREE, the label is a normal case
818 label. CASE_LABEL is the corresponding LABEL_DECL. */
819 DEFTREECODE (CASE_LABEL_EXPR, "case_label_expr", 's', 3)
821 /* RESX. Resume execution after an exception. Operand 0 is a
822 number indicating the exception region that is being left. */
823 DEFTREECODE (RESX_EXPR, "resx_expr", 's', 1)
825 /* Used to represent an inline assembly statement. ASM_STRING returns a
826 STRING_CST for the instruction (e.g., "mov x, y"). ASM_OUTPUTS,
827 ASM_INPUTS, and ASM_CLOBBERS represent the outputs, inputs, and clobbers
828 for the statement. */
829 DEFTREECODE (ASM_EXPR, "asm_expr", 's', 4)
831 /* Variable references for SSA analysis. New SSA names are created every
832 time a variable is assigned a new value. The SSA builder uses SSA_NAME
833 nodes to implement SSA versioning. */
834 DEFTREECODE (SSA_NAME, "ssa_name", 'x', 0)
836 /* SSA PHI operator. PHI_RESULT is the new SSA_NAME node created by
837 the PHI node. PHI_ARG_LENGTH is the number of arguments.
838 PHI_ARG_ELT returns the Ith tuple <ssa_name, edge> from the
839 argument list. Each tuple contains the incoming reaching
840 definition (SSA_NAME node) and the edge via which that definition
841 is coming through. */
842 DEFTREECODE (PHI_NODE, "phi_node", 'x', 0)
844 /* Used to represent a typed exception handler. CATCH_TYPES is the type (or
845 list of types) handled, and CATCH_BODY is the code for the handler. */
846 DEFTREECODE (CATCH_EXPR, "catch_expr", 's', 2)
848 /* Used to represent an exception specification. EH_FILTER_TYPES is a list
849 of allowed types, and EH_FILTER_FAILURE is an expression to evaluate on
850 failure. EH_FILTER_MUST_NOT_THROW controls which range type to use when
852 DEFTREECODE (EH_FILTER_EXPR, "eh_filter_expr", 's', 2)
854 /* Node used for describing a property that is known at compile
856 DEFTREECODE (SCEV_KNOWN, "scev_known", 'e', 0)
858 /* Node used for describing a property that is not known at compile
860 DEFTREECODE (SCEV_NOT_KNOWN, "scev_not_known", 'e', 0)
862 /* Polynomial chains of recurrences.
863 Under the form: cr = {CHREC_LEFT (cr), +, CHREC_RIGHT (cr)}. */
864 DEFTREECODE (POLYNOMIAL_CHREC, "polynomial_chrec", 'e', 3)
866 /* Used to chain children of container statements together.
867 Use the interface in tree-iterator.h to access this node. */
868 DEFTREECODE (STATEMENT_LIST, "statement_list", 'x', 0)
870 /* Value handles. Artificial nodes to represent expressions in
871 partial redundancy elimination (tree-ssa-pre.c). These nodes are
872 used for expression canonicalization. If two expressions compute
873 the same value, they will be assigned the same value handle. */
874 DEFTREECODE (VALUE_HANDLE, "value_handle", 'x', 0)
876 /* Base class information. Holds information about a class as a
877 baseclass of itself or another class. */
878 DEFTREECODE (TREE_BINFO, "tree_binfo", 'x', 0)
880 /* Records the size for an expression of variable size type. This is
881 for use in contexts in which we are accessing the entire object,
882 such as for a function call, or block copy.
883 Operand 0 is the real expression.
884 Operand 1 is the size of the type in the expression. */
885 DEFTREECODE (WITH_SIZE_EXPR, "with_size_expr", 'e', 2)
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