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 GNU CC.
8 GNU CC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GNU CC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GNU CC; see the file COPYING. If not, write to
20 the Free Software Foundation, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
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', `s' and `x' nodes,
38 the 4th element is the number of argument slots to allocate.
39 This determines the size of the tree node object. */
41 /* Any erroneous construct is parsed into a node of this type.
42 This type of node is accepted without complaint in all contexts
43 by later parsing activities, to avoid multiple error messages
45 No fields in these nodes are used except the TREE_CODE. */
46 DEFTREECODE (ERROR_MARK, "error_mark", 'x', 0)
48 /* Used to represent a name (such as, in the DECL_NAME of a decl node).
49 Internally it looks like a STRING_CST node.
50 There is only one IDENTIFIER_NODE ever made for any particular name.
51 Use `get_identifier' to get it (or create it, the first time). */
52 DEFTREECODE (IDENTIFIER_NODE, "identifier_node", 'x', -1)
54 /* Used to hold information to identify an operator (or combination
55 of two operators) considered as a `noun' rather than a `verb'.
56 The first operand is encoded in the TREE_TYPE field. */
57 DEFTREECODE (OP_IDENTIFIER, "op_identifier", 'x', 2)
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', 2)
66 /* These nodes contain an array of tree nodes. */
67 DEFTREECODE (TREE_VEC, "tree_vec", 'x', 2)
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 non-zero 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 non-zero 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 TYPE_SEP Expression for units from one elt to the next.
208 TYPE_SEP_UNIT Number of bits in a unit for previous.
209 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
210 and holds the type to coerce a value of that array type to in C.
211 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
212 in languages (such as Chill) that make a distinction. */
213 /* Array types in C or Pascal */
214 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
216 /* Types of sets for Pascal. Special fields are the same as
217 in an array type. The target type is always a boolean type.
218 Used for both bitstrings and powersets in Chill;
219 TYPE_STRING_FLAG indicates a bitstring. */
220 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
222 /* Struct in C, or record in Pascal. */
224 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
225 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
226 types and enumerators.
227 A few may need to be added for Pascal. */
228 /* See the comment above, before ENUMERAL_TYPE, for how
229 forward references to struct tags are handled in C. */
230 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
232 /* Union in C. Like a struct, except that the offsets of the fields
234 /* See the comment above, before ENUMERAL_TYPE, for how
235 forward references to union tags are handled in C. */
236 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
238 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
239 in each FIELD_DECL determine what the union contains. The first
240 field whose DECL_QUALIFIER expression is true is deemed to occupy
242 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
244 /* Type of functions. Special fields:
245 TREE_TYPE type of value returned.
246 TYPE_ARG_TYPES list of types of arguments expected.
247 this list is made of TREE_LIST nodes.
248 Types of "Procedures" in languages where they are different from functions
249 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
250 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
252 /* This is a language-specific kind of type.
253 Its meaning is defined by the language front end.
254 layout_type does not know how to lay this out,
255 so the front-end must do so manually. */
256 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
260 /* First, the constants. */
262 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
263 32 bits each, giving us a 64 bit constant capability.
264 Note: constants of type char in Pascal are INTEGER_CST,
265 and so are pointer constants such as nil in Pascal or NULL in C.
266 `(int *) 1' in C also results in an INTEGER_CST. */
267 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 2)
269 /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
270 DEFTREECODE (REAL_CST, "real_cst", 'c', 3)
272 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
273 whose contents are other constant nodes.
274 Also there is TREE_CST_RTL. */
275 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 3)
277 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
278 Also there is TREE_CST_RTL. */
279 DEFTREECODE (STRING_CST, "string_cst", 'c', 3)
281 /* Declarations. All references to names are represented as ..._DECL nodes.
282 The decls in one binding context are chained through the TREE_CHAIN field.
283 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
284 (Some decls, most often labels, may have zero as the DECL_NAME).
285 DECL_CONTEXT points to the node representing the context in which
286 this declaration has its scope. For FIELD_DECLs, this is the
287 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
288 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
289 and CONST_DECL nodes, this points to either the FUNCTION_DECL for the
290 containing function, the RECORD_TYPE or UNION_TYPE for the containing
291 type, or NULL_TREE 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_OFFSET holds an integer number of bits offset for the location.
303 DECL_VOFFSET holds an expression for a variable offset; it is
304 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 non-zero 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 /* References to storage. */
353 /* Value is structure or union component.
354 Operand 0 is the structure or union (an expression);
355 operand 1 is the field (a node of type FIELD_DECL). */
356 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
358 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
359 except the position is given explicitly rather than via a FIELD_DECL.
360 Operand 0 is the structure or union expression;
361 operand 1 is a tree giving the number of bits being referenced;
362 operand 2 is a tree giving the position of the first referenced bit.
363 The field can be either a signed or unsigned field;
364 TREE_UNSIGNED says which. */
365 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
367 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
368 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
370 /* Pascal `^` on a file. One operand, an expression for the file. */
371 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
374 Operand 0 is the array; operand 1 is a (single) array index. */
375 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
377 /* Likewise, except that the result is a range ("slice") of the array. The
378 starting index of the resulting array is taken from operand 1 and the size
379 of the range is taken from the type of the expression. */
380 DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", 'r', 2)
382 /* Constructor: return an aggregate value made from specified components.
383 In C, this is used only for structure and array initializers.
384 Also used for SET_TYPE in Chill (and potentially Pascal).
385 The first "operand" is really a pointer to the RTL,
386 for constant constructors only.
387 The second operand is a list of component values
388 made out of a chain of TREE_LIST nodes.
391 The TREE_PURPOSE of each node is the corresponding index.
392 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
393 one for each index in the range. (If the corresponding TREE_VALUE
394 has side-effects, they are evaluated once for each element. Wrap the
395 value in a SAVE_EXPR if you want to evaluate side effects only once.)
397 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
398 The TREE_PURPOSE of each node is a FIELD_DECL.
401 The TREE_VALUE specifies a value (index) in the set that is true.
402 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
403 range of true values. Elements not listed are false (not in the set). */
404 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2)
406 /* The expression types are mostly straightforward, with the fourth argument
407 of DEFTREECODE saying how many operands there are.
408 Unless otherwise specified, the operands are expressions and the
409 types of all the operands and the expression must all be the same. */
411 /* Contains two expressions to compute, one followed by the other.
412 the first value is ignored. The second one's value is used. The
413 type of the first expression need not agree with the other types. */
414 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
416 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
417 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
419 /* Initialization expression. Operand 0 is the variable to initialize;
420 Operand 1 is the initializer. */
421 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
423 /* For TARGET_EXPR, operand 0 is the target of an initialization,
424 operand 1 is the initializer for the target,
425 and operand 2 is the cleanup for this node, if any.
426 and operand 3 is the saved initializer after this node has been
427 expanded once, this is so we can re-expand the tree later. */
428 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
430 /* Conditional expression ( ... ? ... : ... in C).
431 Operand 0 is the condition.
432 Operand 1 is the then-value.
433 Operand 2 is the else-value.
434 Operand 0 may be of any type.
435 Operand 1 must have the same type as the entire expression, unless
436 it unconditionally throws an exception, in which case it should
437 have VOID_TYPE. The same constraints apply to operand 2. */
438 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
440 /* Declare local variables, including making RTL and allocating space.
441 Operand 0 is a chain of VAR_DECL nodes for the variables.
442 Operand 1 is the body, the expression to be computed using
443 the variables. The value of operand 1 becomes that of the BIND_EXPR.
444 Operand 2 is the BLOCK that corresponds to these bindings
445 for debugging purposes. If this BIND_EXPR is actually expanded,
446 that sets the TREE_USED flag in the BLOCK.
448 The BIND_EXPR is not responsible for informing parsers
449 about these variables. If the body is coming from the input file,
450 then the code that creates the BIND_EXPR is also responsible for
451 informing the parser of the variables.
453 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
454 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
455 If the BIND_EXPR should be output for debugging but will not be expanded,
456 set the TREE_USED flag by hand.
458 In order for the BIND_EXPR to be known at all, the code that creates it
459 must also install it as a subblock in the tree of BLOCK
460 nodes for the function. */
461 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
463 /* Function call. Operand 0 is the function.
464 Operand 1 is the argument list, a list of expressions
465 made out of a chain of TREE_LIST nodes. */
466 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 2)
468 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
469 Operand 1 is the expression for "self".
470 Operand 2 is the list of explicit arguments. */
471 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
473 /* Specify a value to compute along with its corresponding cleanup.
474 Operand 0 argument is an expression whose value needs a cleanup.
475 Operand 1 is the cleanup expression for the object.
476 Operand 2 is an RTL_EXPR which will eventually represent that value.
477 The RTL_EXPR is used in this expression, which is how the expression
478 manages to act on the proper value.
479 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
480 it exists, otherwise it is the responsibility of the caller to manually
481 call expand_start_target_temps/expand_end_target_temps, as needed.
483 This differs from TRY_CATCH_EXPR in that operand 2 is always
484 evaluated when an exception isn't thrown when cleanups are run. */
485 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
487 /* Specify a cleanup point.
488 Operand 0 is an expression that may have cleanups. If it does, those
489 cleanups are executed after the expression is expanded.
491 Note that if the expression is a reference to storage, it is forced out
492 of memory before the cleanups are run. This is necessary to handle
493 cases where the cleanups modify the storage referenced; in the
494 expression 't.i', if 't' is a struct with an integer member 'i' and a
495 cleanup which modifies 'i', the value of the expression depends on
496 whether the cleanup is run before or after 't.i' is evaluated. When
497 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
498 the value of 't.i' must be forced out of memory.
500 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
501 BLKmode, because it will not be forced out of memory. */
502 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
504 /* The following two codes are used in languages that have types where
505 some field in an object of the type contains a value that is used in
506 the computation of another field's offset or size and/or the size of
507 the type. The positions and/or sizes of fields can vary from object
508 to object of the same type.
510 Record types with discriminants in Ada or schema types in Pascal are
511 examples of such types. This mechanism is also used to create "fat
512 pointers" for unconstrained array types in Ada; the fat pointer is a
513 structure one of whose fields is a pointer to the actual array type
514 and the other field is a pointer to a template, which is a structure
515 containing the bounds of the array. The bounds in the type pointed
516 to by the first field in the fat pointer refer to the values in the
519 When you wish to construct such a type you need "self-references"
520 that allow you to reference the object having this type from the
521 TYPE node, i.e. without having a variable instantiating this type.
523 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
524 a node that will later be replaced with the object being referenced.
525 Its type is that of the object and selects which object to use from
526 a chain of references (see below). No other slots are used in the
529 For example, if your type FOO is a RECORD_TYPE with a field BAR,
530 and you need the value of <variable>.BAR to calculate TYPE_SIZE
531 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
532 what contains both the expression we wish to
533 evaluate and an expression within which the object may be found.
534 The latter expression is the object itself in the simple case of an
535 Ada record with discriminant, but it can be the array in the case of
536 an unconstrained array.
538 In the latter case, we need the fat pointer, because the bounds of
539 the array can only be accessed from it. However, we rely here on the
540 fact that the expression for the array contains the dereference of
541 the fat pointer that obtained the array pointer.
543 Accordingly, when looking for the object to substitute in place of
544 a PLACEHOLDER_EXPR, we look down the first operand of the expression
545 passed as the second operand to WITH_RECORD_EXPR until we find
546 something of the desired type or reach a constant. */
548 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
549 evaluating this expression. The type of this expression is used to
550 find the record to replace it. */
551 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
553 /* Provide an expression that references a record to be used in place
554 of a PLACEHOLDER_EXPR. The record to be used is the record within
555 operand 1 that has the same type as the PLACEHOLDER_EXPR in
557 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
559 /* Simple arithmetic. */
560 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
561 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
562 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
564 /* Division for integer result that rounds the quotient toward zero. */
565 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
567 /* Division for integer result that rounds the quotient toward infinity. */
568 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
570 /* Division for integer result that rounds toward minus infinity. */
571 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
573 /* Division for integer result that rounds toward nearest integer. */
574 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
576 /* Four kinds of remainder that go with the four kinds of division. */
577 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
578 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
579 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
580 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
582 /* Division for real result. */
583 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
585 /* Division which is not supposed to need rounding.
586 Used for pointer subtraction in C. */
587 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
589 /* Conversion of real to fixed point: four ways to round,
590 like the four ways to divide.
591 CONVERT_EXPR can also be used to convert a real to an integer,
592 and that is what is used in languages that do not have ways of
593 specifying which of these is wanted. Maybe these are not needed. */
594 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
595 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
596 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
597 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
599 /* Conversion of an integer to a real. */
600 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
602 /* Unary negation. */
603 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
605 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
606 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
608 /* Represents the absolute value of the operand.
610 An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
611 operand of the ABS_EXPR must have the same type. */
612 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
614 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
616 /* Shift operations for shift and rotate.
617 Shift means logical shift if done on an
618 unsigned type, arithmetic shift if done on a signed type.
619 The second operand is the number of bits to
620 shift by; it need not be the same type as the first operand and result.
621 Note that the result is undefined if the second operand is larger
622 than the first operand's type size. */
623 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
624 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
625 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
626 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
628 /* Bitwise operations. Operands have same mode as result. */
629 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
630 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
631 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
632 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
633 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
635 /* ANDIF and ORIF allow the second operand not to be computed if the
636 value of the expression is determined from the first operand. AND,
637 OR, and XOR always compute the second operand whether its value is
638 needed or not (for side effects). The operand may have
639 BOOLEAN_TYPE or INTEGER_TYPE. In either case, the argument will be
640 either zero or one. For example, a TRUTH_NOT_EXPR will never have
641 a INTEGER_TYPE VAR_DECL as its argument; instead, a NE_EXPR will be
642 used to compare the VAR_DECL to zero, thereby obtaining a node with
643 value zero or one. */
644 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
645 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
646 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
647 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
648 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
649 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
651 /* Relational operators.
652 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
653 The others are allowed only for integer (or pointer or enumeral)
655 In all cases the operands will have the same type,
656 and the value is always the type used by the language for booleans. */
657 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
658 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
659 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
660 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
661 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
662 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
664 /* Additional relational operators for floating point unordered. */
665 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", '<', 2)
666 DEFTREECODE (ORDERED_EXPR, "ordered_expr", '<', 2)
668 /* These are equivalent to unordered or ... */
669 DEFTREECODE (UNLT_EXPR, "unlt_expr", '<', 2)
670 DEFTREECODE (UNLE_EXPR, "unle_expr", '<', 2)
671 DEFTREECODE (UNGT_EXPR, "ungt_expr", '<', 2)
672 DEFTREECODE (UNGE_EXPR, "unge_expr", '<', 2)
673 DEFTREECODE (UNEQ_EXPR, "uneq_expr", '<', 2)
675 /* Operations for Pascal sets. Not used now. */
676 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
677 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
678 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
679 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
681 /* Represents a conversion of type of a value.
682 All conversions, including implicit ones, must be
683 represented by CONVERT_EXPR or NOP_EXPR nodes. */
684 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
686 /* Represents a conversion expected to require no code to be generated. */
687 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
689 /* Value is same as argument, but guaranteed not an lvalue. */
690 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
692 /* Represents something we computed once and will use multiple times.
693 First operand is that expression. Second is the function decl
694 in which the SAVE_EXPR was created. The third operand is the RTL,
695 nonzero only after the expression has been computed. */
696 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
698 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
699 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
700 CALL_EXPRs and RTL_EXPRs, that are protected
701 from being evaluated more than once should be reset so that a new
702 expand_expr call of this expr will cause those to be re-evaluated.
703 This is useful when we want to reuse a tree in different places,
704 but where we must re-expand. */
705 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
707 /* Represents something whose RTL has already been expanded as a
708 sequence which should be emitted when this expression is expanded.
709 The first operand is the RTL to emit. It is the first of a chain
710 of insns. The second is the RTL expression for the result. Any
711 temporaries created during the building of the RTL_EXPR can be
712 reused once the RTL_EXPR has been expanded, with the exception of
714 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
716 /* & in C. Value is the address at which the operand's value resides.
717 Operand may have any mode. Result mode is Pmode. */
718 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
720 /* Non-lvalue reference or pointer to an object. */
721 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
723 /* Operand is a function constant; result is a function variable value
724 of typeEPmode. Used only for languages that need static chains. */
725 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
727 /* Given two real or integer operands of the same type,
728 returns a complex value of the corresponding complex type. */
729 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
731 /* Complex conjugate of operand. Used only on complex types. */
732 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
734 /* Used only on an operand of complex type, these return
735 a value of the corresponding component type. */
736 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
737 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
739 /* Nodes for ++ and -- in C.
740 The second arg is how much to increment or decrement by.
741 For a pointer, it would be the size of the object pointed to. */
742 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
743 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
744 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
745 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
747 /* Used to implement `va_arg'. */
748 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
750 /* Evaluate operand 1. If and only if an exception is thrown during
751 the evaluation of operand 1, evaluate operand 2.
753 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
754 evaluated unless an exception is throw. */
755 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
757 /* Evaluate the first operand.
758 The second operand is a a cleanup expression which is evaluated
759 before an exit (normal, exception, or jump out) from this expression.
761 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those
762 always copy the cleanup expression where needed. In contrast,
763 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine.
764 (At least conceptually; the optimizer could inline the cleanup
765 subroutine in the same way it could inline normal subroutines.)
766 TRY_FINALLY_EXPR should be used when the cleanup is actual statements
767 in the source of the current function (which people might want to
768 set breakpoints in). */
769 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
771 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
772 (Specifically, it is created by expand_expr, not front-ends.)
773 Operand 0 is the rtx for the start of the subroutine we need to call.
774 Operand 1 is the rtx for a variable in which to store the address
775 of where the subroutine should return to. */
776 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
778 /* These types of expressions have no useful value,
779 and always have side effects. */
781 /* A label definition, encapsulated as a statement.
782 Operand 0 is the LABEL_DECL node for the label that appears here.
783 The type should be void and the value should be ignored. */
784 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
786 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
787 The type should be void and the value should be ignored. */
788 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
790 /* RETURN. Evaluates operand 0, then returns from the current function.
791 Presumably that operand is an assignment that stores into the
792 RESULT_DECL that hold the value to be returned.
793 The operand may be null.
794 The type should be void and the value should be ignored. */
795 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
797 /* Exit the inner most loop conditionally. Operand 0 is the condition.
798 The type should be void and the value should be ignored. */
799 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
801 /* A loop. Operand 0 is the body of the loop.
802 It must contain an EXIT_EXPR or is an infinite loop.
803 The type should be void and the value should be ignored. */
804 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
806 /* A labeled block. Operand 0 is the label that will be generated to
807 mark the end of the block.
808 Operand 1 is the labeled block body. */
809 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
811 /* Exit a labeled block, possibly returning a value. Operand 0 is a
812 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
814 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
816 /* Annotates a tree node (usually an expression) with source location
817 information: a file name (EXPR_WFL_FILENAME); a line number
818 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
819 expanded as the contained node (EXPR_WFL_NODE); a line note should
820 be emitted first if EXPR_WFL_EMIT_LINE_NOTE.
821 The third operand is only used in the Java front-end, and will
822 eventually be removed. */
823 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 3)
825 /* Switch expression.
826 Operand 0 is the expression used to perform the branch,
827 Operand 1 contains the case values. The way they're organized is
828 front-end implementation defined. */
829 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
831 /* The exception object from the runtime. */
832 DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", 'e', 0)