1 /* This file contains the definitions and documentation for the
2 tree codes used in the GNU C compiler.
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 expressions with inherent side effects.
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", 'b', 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
155 DEFTREECODE (VECTOR_TYPE, "vector_type", 't', 0)
157 /* C enums. The type node looks just like an INTEGER_TYPE node.
158 The symbols for the values of the enum type are defined by
159 CONST_DECL nodes, but the type does not point to them;
160 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
161 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
162 /* A forward reference `enum foo' when no enum named foo is defined yet
163 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
164 the TYPE_NAME field. If the type is later defined, the normal
165 fields are filled in.
166 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
167 treated similarly. */
168 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", 't', 0)
170 /* Pascal's boolean type (true or false are the only values);
171 no special fields needed. */
172 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", 't', 0)
174 /* CHAR in Pascal; not used in C.
175 No special fields needed. */
176 DEFTREECODE (CHAR_TYPE, "char_type", 't', 0)
178 /* All pointer-to-x types have code POINTER_TYPE.
179 The TREE_TYPE points to the node for the type pointed to. */
180 DEFTREECODE (POINTER_TYPE, "pointer_type", 't', 0)
182 /* An offset is a pointer relative to an object.
183 The TREE_TYPE field is the type of the object at the offset.
184 The TYPE_OFFSET_BASETYPE points to the node for the type of object
185 that the offset is relative to. */
186 DEFTREECODE (OFFSET_TYPE, "offset_type", 't', 0)
188 /* A reference is like a pointer except that it is coerced
189 automatically to the value it points to. Used in C++. */
190 DEFTREECODE (REFERENCE_TYPE, "reference_type", 't', 0)
192 /* METHOD_TYPE is the type of a function which takes an extra first
193 argument for "self", which is not present in the declared argument list.
194 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
195 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
196 includes the hidden argument for "self". */
197 DEFTREECODE (METHOD_TYPE, "method_type", 't', 0)
199 /* Used for Pascal; details not determined right now. */
200 DEFTREECODE (FILE_TYPE, "file_type", 't', 0)
202 /* Types of arrays. Special fields:
203 TREE_TYPE Type of an array element.
204 TYPE_DOMAIN Type to index by.
205 Its range of values specifies the array length.
206 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
207 and holds the type to coerce a value of that array type to in C.
208 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
209 in languages (such as Chill) that make a distinction. */
210 /* Array types in C or Pascal */
211 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
213 /* Types of sets for Pascal. Special fields are the same as
214 in an array type. The target type is always a boolean type.
215 Used for both bitstrings and powersets in Chill;
216 TYPE_STRING_FLAG indicates a bitstring. */
217 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
219 /* Struct in C, or record in Pascal. */
221 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
222 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
223 types and enumerators.
224 A few may need to be added for Pascal. */
225 /* See the comment above, before ENUMERAL_TYPE, for how
226 forward references to struct tags are handled in C. */
227 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
229 /* Union in C. Like a struct, except that the offsets of the fields
231 /* See the comment above, before ENUMERAL_TYPE, for how
232 forward references to union tags are handled in C. */
233 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
235 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
236 in each FIELD_DECL determine what the union contains. The first
237 field whose DECL_QUALIFIER expression is true is deemed to occupy
239 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
241 /* Type of functions. Special fields:
242 TREE_TYPE type of value returned.
243 TYPE_ARG_TYPES list of types of arguments expected.
244 this list is made of TREE_LIST nodes.
245 Types of "Procedures" in languages where they are different from functions
246 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
247 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
249 /* This is a language-specific kind of type.
250 Its meaning is defined by the language front end.
251 layout_type does not know how to lay this out,
252 so the front-end must do so manually. */
253 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
257 /* First, the constants. */
259 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
260 32 bits each, giving us a 64 bit constant capability.
261 Note: constants of type char in Pascal are INTEGER_CST,
262 and so are pointer constants such as nil in Pascal or NULL in C.
263 `(int *) 1' in C also results in an INTEGER_CST. */
264 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 0)
266 /* Contents are in TREE_REAL_CST field. */
267 DEFTREECODE (REAL_CST, "real_cst", 'c', 0)
269 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
270 whose contents are other constant nodes. */
271 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 0)
273 /* Contents are in TREE_VECTOR_CST_ELTS field. */
274 DEFTREECODE (VECTOR_CST, "vector_cst", 'c', 0)
276 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields. */
277 DEFTREECODE (STRING_CST, "string_cst", 'c', 0)
279 /* Declarations. All references to names are represented as ..._DECL nodes.
280 The decls in one binding context are chained through the TREE_CHAIN field.
281 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
282 (Some decls, most often labels, may have zero as the DECL_NAME).
283 DECL_CONTEXT points to the node representing the context in which
284 this declaration has its scope. For FIELD_DECLs, this is the
285 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
286 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
287 and CONST_DECL nodes, this points to either the FUNCTION_DECL for the
288 containing function, the RECORD_TYPE or UNION_TYPE for the containing
289 type, or NULL_TREE if the given decl has "file scope".
290 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
291 ..._DECL node of which this decl is an (inlined or template expanded)
293 The TREE_TYPE field holds the data type of the object, when relevant.
294 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
295 contents are the type whose name is being declared.
296 The DECL_ALIGN, DECL_SIZE,
297 and DECL_MODE fields exist in decl nodes just as in type nodes.
298 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
300 DECL_OFFSET holds an integer number of bits offset for the location.
301 DECL_VOFFSET holds an expression for a variable offset; it is
302 to be multiplied by DECL_VOFFSET_UNIT (an integer).
303 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
305 DECL_INITIAL holds the value to initialize a variable to,
306 or the value of a constant. For a function, it holds the body
307 (a node of type BLOCK representing the function's binding contour
308 and whose body contains the function's statements.) For a LABEL_DECL
309 in C, it is a flag, nonzero if the label's definition has been seen.
311 PARM_DECLs use a special field:
312 DECL_ARG_TYPE is the type in which the argument is actually
313 passed, which may be different from its type within the function.
315 FUNCTION_DECLs use four special fields:
316 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
317 DECL_RESULT holds a RESULT_DECL node for the value of a function,
318 or it is 0 for a function that returns no value.
319 (C functions returning void have zero here.)
320 The TREE_TYPE field is the type in which the result is actually
321 returned. This is usually the same as the return type of the
322 FUNCTION_DECL, but it may be a wider integer type because of
324 DECL_FUNCTION_CODE is a code number that is nonzero for
325 built-in functions. Its value is an enum built_in_function
326 that says which built-in function it is.
328 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
329 holds a line number. In some cases these can be the location of
330 a reference, if no definition has been seen.
332 DECL_ABSTRACT is nonzero if the decl represents an abstract instance
333 of a decl (i.e. one which is nested within an abstract instance of a
336 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
337 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
338 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
339 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
340 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
341 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
342 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
343 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
345 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
346 _DECLs, providing a hierarchy of names. */
347 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
349 /* References to storage. */
351 /* Value is structure or union component.
352 Operand 0 is the structure or union (an expression);
353 operand 1 is the field (a node of type FIELD_DECL). */
354 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
356 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
357 except the position is given explicitly rather than via a FIELD_DECL.
358 Operand 0 is the structure or union expression;
359 operand 1 is a tree giving the number of bits being referenced;
360 operand 2 is a tree giving the position of the first referenced bit.
361 The field can be either a signed or unsigned field;
362 TREE_UNSIGNED says which. */
363 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
365 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
366 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
368 /* Pascal `^` on a file. One operand, an expression for the file. */
369 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
372 Operand 0 is the array; operand 1 is a (single) array index. */
373 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
375 /* Likewise, except that the result is a range ("slice") of the array. The
376 starting index of the resulting array is taken from operand 1 and the size
377 of the range is taken from the type of the expression. */
378 DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", 'r', 2)
380 /* Vtable indexing. Carries data useful for emitting information
381 for vtable garbage collection.
382 Operand 0: an array_ref (or equivalent expression)
383 Operand 1: the vtable base (must be a var_decl)
384 Operand 2: index into vtable (must be an integer_cst). */
385 DEFTREECODE (VTABLE_REF, "vtable_ref", 'r', 3)
387 /* Constructor: return an aggregate value made from specified components.
388 In C, this is used only for structure and array initializers.
389 Also used for SET_TYPE in Chill (and potentially Pascal).
390 The first "operand" is really a pointer to the RTL,
391 for constant constructors only.
392 The second operand is a list of component values
393 made out of a chain of TREE_LIST nodes.
396 The TREE_PURPOSE of each node is the corresponding index.
397 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
398 one for each index in the range. (If the corresponding TREE_VALUE
399 has side-effects, they are evaluated once for each element. Wrap the
400 value in a SAVE_EXPR if you want to evaluate side effects only once.)
402 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
403 The TREE_PURPOSE of each node is a FIELD_DECL.
406 The TREE_VALUE specifies a value (index) in the set that is true.
407 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
408 range of true values. Elements not listed are false (not in the set). */
409 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2)
411 /* The expression types are mostly straightforward, with the fourth argument
412 of DEFTREECODE saying how many operands there are.
413 Unless otherwise specified, the operands are expressions and the
414 types of all the operands and the expression must all be the same. */
416 /* Contains two expressions to compute, one followed by the other.
417 the first value is ignored. The second one's value is used. The
418 type of the first expression need not agree with the other types. */
419 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
421 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
422 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
424 /* Initialization expression. Operand 0 is the variable to initialize;
425 Operand 1 is the initializer. */
426 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
428 /* For TARGET_EXPR, operand 0 is the target of an initialization,
429 operand 1 is the initializer for the target,
430 and operand 2 is the cleanup for this node, if any.
431 and operand 3 is the saved initializer after this node has been
432 expanded once, this is so we can re-expand the tree later. */
433 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
435 /* Conditional expression ( ... ? ... : ... in C).
436 Operand 0 is the condition.
437 Operand 1 is the then-value.
438 Operand 2 is the else-value.
439 Operand 0 may be of any type.
440 Operand 1 must have the same type as the entire expression, unless
441 it unconditionally throws an exception, in which case it should
442 have VOID_TYPE. The same constraints apply to operand 2. */
443 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
445 /* Declare local variables, including making RTL and allocating space.
446 Operand 0 is a chain of VAR_DECL nodes for the variables.
447 Operand 1 is the body, the expression to be computed using
448 the variables. The value of operand 1 becomes that of the BIND_EXPR.
449 Operand 2 is the BLOCK that corresponds to these bindings
450 for debugging purposes. If this BIND_EXPR is actually expanded,
451 that sets the TREE_USED flag in the BLOCK.
453 The BIND_EXPR is not responsible for informing parsers
454 about these variables. If the body is coming from the input file,
455 then the code that creates the BIND_EXPR is also responsible for
456 informing the parser of the variables.
458 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
459 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
460 If the BIND_EXPR should be output for debugging but will not be expanded,
461 set the TREE_USED flag by hand.
463 In order for the BIND_EXPR to be known at all, the code that creates it
464 must also install it as a subblock in the tree of BLOCK
465 nodes for the function. */
466 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
468 /* Function call. Operand 0 is the function.
469 Operand 1 is the argument list, a list of expressions
470 made out of a chain of TREE_LIST nodes. */
471 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 2)
473 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
474 Operand 1 is the expression for "self".
475 Operand 2 is the list of explicit arguments. */
476 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
478 /* Specify a value to compute along with its corresponding cleanup.
479 Operand 0 argument is an expression whose value needs a cleanup.
480 Operand 1 is the cleanup expression for the object.
481 Operand 2 is an RTL_EXPR which will eventually represent that value.
482 The RTL_EXPR is used in this expression, which is how the expression
483 manages to act on the proper value.
484 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
485 it exists, otherwise it is the responsibility of the caller to manually
486 call expand_start_target_temps/expand_end_target_temps, as needed.
488 This differs from TRY_CATCH_EXPR in that operand 2 is always
489 evaluated when an exception isn't thrown when cleanups are run. */
490 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
492 /* Specify a cleanup point.
493 Operand 0 is an expression that may have cleanups. If it does, those
494 cleanups are executed after the expression is expanded.
496 Note that if the expression is a reference to storage, it is forced out
497 of memory before the cleanups are run. This is necessary to handle
498 cases where the cleanups modify the storage referenced; in the
499 expression 't.i', if 't' is a struct with an integer member 'i' and a
500 cleanup which modifies 'i', the value of the expression depends on
501 whether the cleanup is run before or after 't.i' is evaluated. When
502 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
503 the value of 't.i' must be forced out of memory.
505 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
506 BLKmode, because it will not be forced out of memory. */
507 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
509 /* The following two codes are used in languages that have types where
510 some field in an object of the type contains a value that is used in
511 the computation of another field's offset or size and/or the size of
512 the type. The positions and/or sizes of fields can vary from object
513 to object of the same type.
515 Record types with discriminants in Ada or schema types in Pascal are
516 examples of such types. This mechanism is also used to create "fat
517 pointers" for unconstrained array types in Ada; the fat pointer is a
518 structure one of whose fields is a pointer to the actual array type
519 and the other field is a pointer to a template, which is a structure
520 containing the bounds of the array. The bounds in the type pointed
521 to by the first field in the fat pointer refer to the values in the
524 When you wish to construct such a type you need "self-references"
525 that allow you to reference the object having this type from the
526 TYPE node, i.e. without having a variable instantiating this type.
528 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
529 a node that will later be replaced with the object being referenced.
530 Its type is that of the object and selects which object to use from
531 a chain of references (see below). No other slots are used in the
534 For example, if your type FOO is a RECORD_TYPE with a field BAR,
535 and you need the value of <variable>.BAR to calculate TYPE_SIZE
536 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
537 what contains both the expression we wish to
538 evaluate and an expression within which the object may be found.
539 The latter expression is the object itself in the simple case of an
540 Ada record with discriminant, but it can be the array in the case of
541 an unconstrained array.
543 In the latter case, we need the fat pointer, because the bounds of
544 the array can only be accessed from it. However, we rely here on the
545 fact that the expression for the array contains the dereference of
546 the fat pointer that obtained the array pointer.
548 Accordingly, when looking for the object to substitute in place of
549 a PLACEHOLDER_EXPR, we look down the first operand of the expression
550 passed as the second operand to WITH_RECORD_EXPR until we find
551 something of the desired type or reach a constant. */
553 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
554 evaluating this expression. The type of this expression is used to
555 find the record to replace it. */
556 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
558 /* Provide an expression that references a record to be used in place
559 of a PLACEHOLDER_EXPR. The record to be used is the record within
560 operand 1 that has the same type as the PLACEHOLDER_EXPR in
562 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
564 /* Simple arithmetic. */
565 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
566 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
567 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
569 /* Division for integer result that rounds the quotient toward zero. */
570 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
572 /* Division for integer result that rounds the quotient toward infinity. */
573 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
575 /* Division for integer result that rounds toward minus infinity. */
576 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
578 /* Division for integer result that rounds toward nearest integer. */
579 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
581 /* Four kinds of remainder that go with the four kinds of division. */
582 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
583 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
584 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
585 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
587 /* Division for real result. */
588 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
590 /* Division which is not supposed to need rounding.
591 Used for pointer subtraction in C. */
592 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
594 /* Conversion of real to fixed point: four ways to round,
595 like the four ways to divide.
596 CONVERT_EXPR can also be used to convert a real to an integer,
597 and that is what is used in languages that do not have ways of
598 specifying which of these is wanted. Maybe these are not needed. */
599 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
600 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
601 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
602 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
604 /* Conversion of an integer to a real. */
605 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
607 /* Unary negation. */
608 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
610 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
611 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
613 /* Represents the absolute value of the operand.
615 An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
616 operand of the ABS_EXPR must have the same type. */
617 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
619 /* Bit scanning and counting. */
620 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
621 DEFTREECODE (CLZ_EXPR, "clz_expr", '1', 1)
622 DEFTREECODE (CTZ_EXPR, "ctz_expr", '1', 1)
623 DEFTREECODE (POPCOUNT_EXPR, "popcount_expr", '1', 1)
624 DEFTREECODE (PARITY_EXPR, "parity_expr", '1', 1)
626 /* Shift operations for shift and rotate.
627 Shift means logical shift if done on an
628 unsigned type, arithmetic shift if done on a signed type.
629 The second operand is the number of bits to
630 shift by; it need not be the same type as the first operand and result.
631 Note that the result is undefined if the second operand is larger
632 than the first operand's type size. */
633 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
634 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
635 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
636 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
638 /* Bitwise operations. Operands have same mode as result. */
639 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
640 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
641 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
642 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
643 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
645 /* ANDIF and ORIF allow the second operand not to be computed if the
646 value of the expression is determined from the first operand. AND,
647 OR, and XOR always compute the second operand whether its value is
648 needed or not (for side effects). The operand may have
649 BOOLEAN_TYPE or INTEGER_TYPE. In either case, the argument will be
650 either zero or one. For example, a TRUTH_NOT_EXPR will never have
651 an INTEGER_TYPE VAR_DECL as its argument; instead, a NE_EXPR will be
652 used to compare the VAR_DECL to zero, thereby obtaining a node with
653 value zero or one. */
654 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
655 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
656 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
657 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
658 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
659 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
661 /* Relational operators.
662 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
663 The others are allowed only for integer (or pointer or enumeral)
665 In all cases the operands will have the same type,
666 and the value is always the type used by the language for booleans. */
667 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
668 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
669 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
670 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
671 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
672 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
674 /* Additional relational operators for floating point unordered. */
675 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", '<', 2)
676 DEFTREECODE (ORDERED_EXPR, "ordered_expr", '<', 2)
678 /* These are equivalent to unordered or ... */
679 DEFTREECODE (UNLT_EXPR, "unlt_expr", '<', 2)
680 DEFTREECODE (UNLE_EXPR, "unle_expr", '<', 2)
681 DEFTREECODE (UNGT_EXPR, "ungt_expr", '<', 2)
682 DEFTREECODE (UNGE_EXPR, "unge_expr", '<', 2)
683 DEFTREECODE (UNEQ_EXPR, "uneq_expr", '<', 2)
685 /* Operations for Pascal sets. Not used now. */
686 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
687 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
688 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
689 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
691 /* Represents a conversion of type of a value.
692 All conversions, including implicit ones, must be
693 represented by CONVERT_EXPR or NOP_EXPR nodes. */
694 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
696 /* Represents a conversion expected to require no code to be generated. */
697 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
699 /* Value is same as argument, but guaranteed not an lvalue. */
700 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
702 /* Represents viewing something of one type as being of a second type.
703 This corresponds to an "Unchecked Conversion" in Ada and roughly to
704 the idiom *(type2 *)&X in C. The only operand is the value to be
705 viewed as being of another type. It is undefined if the type of the
706 input and of the expression have different sizes.
708 This code may also be used within the LHS of a MODIFY_EXPR, in which
709 case no actual data motion may occur. TREE_ADDRESSABLE will be set in
710 this case and GCC must abort if it could not do the operation without
712 DEFTREECODE (VIEW_CONVERT_EXPR, "view_convert_expr", '1', 1)
714 /* Represents something we computed once and will use multiple times.
715 First operand is that expression. Second is the function decl
716 in which the SAVE_EXPR was created. The third operand is the RTL,
717 nonzero only after the expression has been computed. */
718 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
720 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
721 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
722 CALL_EXPRs and RTL_EXPRs, that are protected
723 from being evaluated more than once should be reset so that a new
724 expand_expr call of this expr will cause those to be re-evaluated.
725 This is useful when we want to reuse a tree in different places,
726 but where we must re-expand. */
727 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
729 /* Represents something whose RTL has already been expanded as a
730 sequence which should be emitted when this expression is expanded.
731 The first operand is the RTL to emit. It is the first of a chain
732 of insns. The second is the RTL expression for the result. Any
733 temporaries created during the building of the RTL_EXPR can be
734 reused once the RTL_EXPR has been expanded, with the exception of
736 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
738 /* & in C. Value is the address at which the operand's value resides.
739 Operand may have any mode. Result mode is Pmode. */
740 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
742 /* Non-lvalue reference or pointer to an object. */
743 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
745 /* Operand is a function constant; result is a function variable value
746 of type EPmode. Used only for languages that need static chains. */
747 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
749 /* Operand0 is a function constant; result is part N of a function
750 descriptor of type ptr_mode. */
751 DEFTREECODE (FDESC_EXPR, "fdesc_expr", 'e', 2)
753 /* Given two real or integer operands of the same type,
754 returns a complex value of the corresponding complex type. */
755 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
757 /* Complex conjugate of operand. Used only on complex types. */
758 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
760 /* Used only on an operand of complex type, these return
761 a value of the corresponding component type. */
762 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
763 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
765 /* Nodes for ++ and -- in C.
766 The second arg is how much to increment or decrement by.
767 For a pointer, it would be the size of the object pointed to. */
768 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
769 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
770 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
771 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
773 /* Used to implement `va_arg'. */
774 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
776 /* Evaluate operand 1. If and only if an exception is thrown during
777 the evaluation of operand 1, evaluate operand 2.
779 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
780 evaluated unless an exception is throw. */
781 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
783 /* Evaluate the first operand.
784 The second operand is a cleanup expression which is evaluated
785 before an exit (normal, exception, or jump out) from this expression.
787 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those
788 always copy the cleanup expression where needed. In contrast,
789 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine.
790 (At least conceptually; the optimizer could inline the cleanup
791 subroutine in the same way it could inline normal subroutines.)
792 TRY_FINALLY_EXPR should be used when the cleanup is actual statements
793 in the source of the current function (which people might want to
794 set breakpoints in). */
795 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
797 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
798 (Specifically, it is created by expand_expr, not front-ends.)
799 Operand 0 is the rtx for the start of the subroutine we need to call.
800 Operand 1 is the rtx for a variable in which to store the address
801 of where the subroutine should return to. */
802 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
804 /* These types of expressions have no useful value,
805 and always have side effects. */
807 /* A label definition, encapsulated as a statement.
808 Operand 0 is the LABEL_DECL node for the label that appears here.
809 The type should be void and the value should be ignored. */
810 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
812 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
813 The type should be void and the value should be ignored. */
814 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
816 /* RETURN. Evaluates operand 0, then returns from the current function.
817 Presumably that operand is an assignment that stores into the
818 RESULT_DECL that hold the value to be returned.
819 The operand may be null.
820 The type should be void and the value should be ignored. */
821 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
823 /* Exit the inner most loop conditionally. Operand 0 is the condition.
824 The type should be void and the value should be ignored. */
825 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
827 /* A loop. Operand 0 is the body of the loop.
828 It must contain an EXIT_EXPR or is an infinite loop.
829 The type should be void and the value should be ignored. */
830 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
832 /* A labeled block. Operand 0 is the label that will be generated to
833 mark the end of the block.
834 Operand 1 is the labeled block body. */
835 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
837 /* Exit a labeled block, possibly returning a value. Operand 0 is a
838 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
840 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
842 /* Annotates a tree node (usually an expression) with source location
843 information: a file name (EXPR_WFL_FILENAME); a line number
844 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
845 expanded as the contained node (EXPR_WFL_NODE); a line note should
846 be emitted first if EXPR_WFL_EMIT_LINE_NOTE.
847 The third operand is only used in the Java front-end, and will
848 eventually be removed. */
849 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 3)
851 /* Switch expression.
852 Operand 0 is the expression used to perform the branch,
853 Operand 1 contains the case values. The way they're organized is
854 front-end implementation defined. */
855 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
857 /* The exception object from the runtime. */
858 DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", 'e', 0)
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