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 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* The third argument can be:
24 'x' for an exceptional code (fits no category).
25 't' for a type object code.
26 'b' for a lexical block.
27 'c' for codes for constants.
28 'd' for codes for declarations (also serving as variable refs).
29 'r' for codes for references to storage.
30 '<' for codes for comparison expressions.
31 '1' for codes for unary arithmetic expressions.
32 '2' for codes for binary arithmetic expressions.
33 's' for codes for expressions with inherent side effects.
34 'e' for codes for other kinds of expressions. */
36 /* For `r', `e', `<', `1', `2', `s' and `x' nodes,
37 the 4th element is the number of argument slots to allocate.
38 This determines the size of the tree node object. */
40 /* Any erroneous construct is parsed into a node of this type.
41 This type of node is accepted without complaint in all contexts
42 by later parsing activities, to avoid multiple error messages
44 No fields in these nodes are used except the TREE_CODE. */
45 DEFTREECODE (ERROR_MARK, "error_mark", 'x', 0)
47 /* Used to represent a name (such as, in the DECL_NAME of a decl node).
48 Internally it looks like a STRING_CST node.
49 There is only one IDENTIFIER_NODE ever made for any particular name.
50 Use `get_identifier' to get it (or create it, the first time). */
51 DEFTREECODE (IDENTIFIER_NODE, "identifier_node", 'x', -1)
53 /* Used to hold information to identify an operator (or combination
54 of two operators) considered as a `noun' rather than a `verb'.
55 The first operand is encoded in the TREE_TYPE field. */
56 DEFTREECODE (OP_IDENTIFIER, "op_identifier", 'x', 2)
58 /* Has the TREE_VALUE and TREE_PURPOSE fields. */
59 /* These nodes are made into lists by chaining through the
60 TREE_CHAIN field. The elements of the list live in the
61 TREE_VALUE fields, while TREE_PURPOSE fields are occasionally
62 used as well to get the effect of Lisp association lists. */
63 DEFTREECODE (TREE_LIST, "tree_list", 'x', 2)
65 /* These nodes contain an array of tree nodes. */
66 DEFTREECODE (TREE_VEC, "tree_vec", 'x', 2)
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 non-zero if the block represents an abstract
84 instance of a block (i.e. one which is nested within an abstract
85 instance of an inline function).
86 TREE_ASM_WRITTEN is non-zero 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 TYPE_SEP Expression for units from one elt to the next.
207 TYPE_SEP_UNIT Number of bits in a unit for previous.
208 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
209 and holds the type to coerce a value of that array type to in C.
210 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
211 in languages (such as Chill) that make a distinction. */
212 /* Array types in C or Pascal */
213 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
215 /* Types of sets for Pascal. Special fields are the same as
216 in an array type. The target type is always a boolean type.
217 Used for both bitstrings and powersets in Chill;
218 TYPE_STRING_FLAG indicates a bitstring. */
219 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
221 /* Struct in C, or record in Pascal. */
223 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
224 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
225 types and enumerators.
226 A few may need to be added for Pascal. */
227 /* See the comment above, before ENUMERAL_TYPE, for how
228 forward references to struct tags are handled in C. */
229 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
231 /* Union in C. Like a struct, except that the offsets of the fields
233 /* See the comment above, before ENUMERAL_TYPE, for how
234 forward references to union tags are handled in C. */
235 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
237 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
238 in each FIELD_DECL determine what the union contains. The first
239 field whose DECL_QUALIFIER expression is true is deemed to occupy
241 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
243 /* Type of functions. Special fields:
244 TREE_TYPE type of value returned.
245 TYPE_ARG_TYPES list of types of arguments expected.
246 this list is made of TREE_LIST nodes.
247 Types of "Procedures" in languages where they are different from functions
248 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
249 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
251 /* This is a language-specific kind of type.
252 Its meaning is defined by the language front end.
253 layout_type does not know how to lay this out,
254 so the front-end must do so manually. */
255 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
259 /* First, the constants. */
261 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
262 32 bits each, giving us a 64 bit constant capability.
263 Note: constants of type char in Pascal are INTEGER_CST,
264 and so are pointer constants such as nil in Pascal or NULL in C.
265 `(int *) 1' in C also results in an INTEGER_CST. */
266 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 2)
268 /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
269 DEFTREECODE (REAL_CST, "real_cst", 'c', 3)
271 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
272 whose contents are other constant nodes.
273 Also there is TREE_CST_RTL. */
274 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 3)
276 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
277 Also there is TREE_CST_RTL. */
278 DEFTREECODE (STRING_CST, "string_cst", 'c', 3)
280 /* Declarations. All references to names are represented as ..._DECL nodes.
281 The decls in one binding context are chained through the TREE_CHAIN field.
282 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
283 (Some decls, most often labels, may have zero as the DECL_NAME).
284 DECL_CONTEXT points to the node representing the context in which
285 this declaration has its scope. For FIELD_DECLs, this is the
286 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
287 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
288 and CONST_DECL nodes, this points to either the FUNCTION_DECL for the
289 containing function, the RECORD_TYPE or UNION_TYPE for the containing
290 type, or NULL_TREE if the given decl has "file scope".
291 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
292 ..._DECL node of which this decl is an (inlined or template expanded)
294 The TREE_TYPE field holds the data type of the object, when relevant.
295 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
296 contents are the type whose name is being declared.
297 The DECL_ALIGN, DECL_SIZE,
298 and DECL_MODE fields exist in decl nodes just as in type nodes.
299 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
301 DECL_OFFSET holds an integer number of bits offset for the location.
302 DECL_VOFFSET holds an expression for a variable offset; it is
303 to be multiplied by DECL_VOFFSET_UNIT (an integer).
304 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
306 DECL_INITIAL holds the value to initialize a variable to,
307 or the value of a constant. For a function, it holds the body
308 (a node of type BLOCK representing the function's binding contour
309 and whose body contains the function's statements.) For a LABEL_DECL
310 in C, it is a flag, nonzero if the label's definition has been seen.
312 PARM_DECLs use a special field:
313 DECL_ARG_TYPE is the type in which the argument is actually
314 passed, which may be different from its type within the function.
316 FUNCTION_DECLs use four special fields:
317 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
318 DECL_RESULT holds a RESULT_DECL node for the value of a function,
319 or it is 0 for a function that returns no value.
320 (C functions returning void have zero here.)
321 The TREE_TYPE field is the type in which the result is actually
322 returned. This is usually the same as the return type of the
323 FUNCTION_DECL, but it may be a wider integer type because of
325 DECL_FUNCTION_CODE is a code number that is nonzero for
326 built-in functions. Its value is an enum built_in_function
327 that says which built-in function it is.
329 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
330 holds a line number. In some cases these can be the location of
331 a reference, if no definition has been seen.
333 DECL_ABSTRACT is non-zero if the decl represents an abstract instance
334 of a decl (i.e. one which is nested within an abstract instance of a
337 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
338 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
339 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
340 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
341 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
342 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
343 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
344 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
346 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
347 _DECLs, providing a hierarchy of names. */
348 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
350 /* References to storage. */
352 /* Value is structure or union component.
353 Operand 0 is the structure or union (an expression);
354 operand 1 is the field (a node of type FIELD_DECL). */
355 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
357 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
358 except the position is given explicitly rather than via a FIELD_DECL.
359 Operand 0 is the structure or union expression;
360 operand 1 is a tree giving the number of bits being referenced;
361 operand 2 is a tree giving the position of the first referenced bit.
362 The field can be either a signed or unsigned field;
363 TREE_UNSIGNED says which. */
364 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
366 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
367 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
369 /* Pascal `^` on a file. One operand, an expression for the file. */
370 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
372 /* Array indexing in languages other than C.
373 Operand 0 is the array; operand 1 is a (single) array index. */
374 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
376 /* Constructor: return an aggregate value made from specified components.
377 In C, this is used only for structure and array initializers.
378 Also used for SET_TYPE in Chill (and potentially Pascal).
379 The first "operand" is really a pointer to the RTL,
380 for constant constructors only.
381 The second operand is a list of component values
382 made out of a chain of TREE_LIST nodes.
385 The TREE_PURPOSE of each node is the corresponding index.
386 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
387 one for each index in the range. (If the corresponding TREE_VALUE
388 has side-effects, they are evaluated once for each element. Wrap the
389 value in a SAVE_EXPR if you want to evaluate side effects only once.)
391 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
392 The TREE_PURPOSE of each node is a FIELD_DECL.
395 The TREE_VALUE specifies a value (index) in the set that is true.
396 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
397 range of true values. Elements not listed are false (not in the set). */
398 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2)
400 /* The expression types are mostly straightforward, with the fourth argument
401 of DEFTREECODE saying how many operands there are.
402 Unless otherwise specified, the operands are expressions and the
403 types of all the operands and the expression must all be the same. */
405 /* Contains two expressions to compute, one followed by the other.
406 the first value is ignored. The second one's value is used. The
407 type of the first expression need not agree with the other types. */
408 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
410 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
411 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
413 /* Initialization expression. Operand 0 is the variable to initialize;
414 Operand 1 is the initializer. */
415 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
417 /* For TARGET_EXPR, operand 0 is the target of an initialization,
418 operand 1 is the initializer for the target,
419 and operand 2 is the cleanup for this node, if any.
420 and operand 3 is the saved initializer after this node has been
421 expanded once, this is so we can re-expand the tree later. */
422 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
424 /* Conditional expression ( ... ? ... : ... in C).
425 Operand 0 is the condition.
426 Operand 1 is the then-value.
427 Operand 2 is the else-value.
428 Operand 0 may be of any type, but the types of operands 1 and 2
429 must be the same and the same as the type of this expression. */
430 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
432 /* Declare local variables, including making RTL and allocating space.
433 Operand 0 is a chain of VAR_DECL nodes for the variables.
434 Operand 1 is the body, the expression to be computed using
435 the variables. The value of operand 1 becomes that of the BIND_EXPR.
436 Operand 2 is the BLOCK that corresponds to these bindings
437 for debugging purposes. If this BIND_EXPR is actually expanded,
438 that sets the TREE_USED flag in the BLOCK.
440 The BIND_EXPR is not responsible for informing parsers
441 about these variables. If the body is coming from the input file,
442 then the code that creates the BIND_EXPR is also responsible for
443 informing the parser of the variables.
445 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
446 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
447 If the BIND_EXPR should be output for debugging but will not be expanded,
448 set the TREE_USED flag by hand.
450 In order for the BIND_EXPR to be known at all, the code that creates it
451 must also install it as a subblock in the tree of BLOCK
452 nodes for the function. */
453 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
455 /* Function call. Operand 0 is the function.
456 Operand 1 is the argument list, a list of expressions
457 made out of a chain of TREE_LIST nodes.
458 There is no operand 2. That slot is used for the
459 CALL_EXPR_RTL macro (see preexpand_calls). */
460 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 3)
462 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
463 Operand 1 is the expression for "self".
464 Operand 2 is the list of explicit arguments. */
465 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
467 /* Specify a value to compute along with its corresponding cleanup.
468 Operand 0 argument is an expression whose value needs a cleanup.
469 Operand 1 is an RTL_EXPR which will eventually represent that value.
470 Operand 2 is the cleanup expression for the object.
471 The RTL_EXPR is used in this expression, which is how the expression
472 manages to act on the proper value.
473 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
474 it exists, otherwise it is the responsibility of the caller to manually
475 call expand_start_target_temps/expand_end_target_temps, as needed.
477 This differs from TRY_CATCH_EXPR in that operand 2 is always
478 evaluated when an exception isn't thrown when cleanups are run. */
479 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
481 /* Specify a cleanup point.
482 Operand 0 is an expression that may have cleanups. If it does, those
483 cleanups are executed after the expression is expanded.
485 Note that if the expression is a reference to storage, it is forced out
486 of memory before the cleanups are run. This is necessary to handle
487 cases where the cleanups modify the storage referenced; in the
488 expression 't.i', if 't' is a struct with an integer member 'i' and a
489 cleanup which modifies 'i', the value of the expression depends on
490 whether the cleanup is run before or after 't.i' is evaluated. When
491 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
492 the value of 't.i' must be forced out of memory.
494 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
495 BLKmode, because it will not be forced out of memory. */
496 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
498 /* The following two codes are used in languages that have types where
499 some field in an object of the type contains a value that is used in
500 the computation of another field's offset or size and/or the size of
501 the type. The positions and/or sizes of fields can vary from object
502 to object of the same type.
504 Record types with discriminants in Ada or schema types in Pascal are
505 examples of such types. This mechanism is also used to create "fat
506 pointers" for unconstrained array types in Ada; the fat pointer is a
507 structure one of whose fields is a pointer to the actual array type
508 and the other field is a pointer to a template, which is a structure
509 containing the bounds of the array. The bounds in the type pointed
510 to by the first field in the fat pointer refer to the values in the
513 When you wish to construct such a type you need "self-references"
514 that allow you to reference the object having this type from the
515 TYPE node, i.e. without having a variable instantiating this type.
517 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
518 a node that will later be replaced with the object being referenced.
519 Its type is that of the object and selects which object to use from
520 a chain of references (see below). No other slots are used in the
523 For example, if your type FOO is a RECORD_TYPE with a field BAR,
524 and you need the value of <variable>.BAR to calculate TYPE_SIZE
525 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
526 what contains both the expression we wish to
527 evaluate and an expression within which the object may be found.
528 The latter expression is the object itself in the simple case of an
529 Ada record with discriminant, but it can be the array in the case of
530 an unconstrained array.
532 In the latter case, we need the fat pointer, because the bounds of
533 the array can only be accessed from it. However, we rely here on the
534 fact that the expression for the array contains the dereference of
535 the fat pointer that obtained the array pointer.
537 Accordingly, when looking for the object to substitute in place of
538 a PLACEHOLDER_EXPR, we look down the first operand of the expression
539 passed as the second operand to WITH_RECORD_EXPR until we find
540 something of the desired type or reach a constant. */
542 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
543 evaluating this expression. The type of this expression is used to
544 find the record to replace it. */
545 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
547 /* Provide an expression that references a record to be used in place
548 of a PLACEHOLDER_EXPR. The record to be used is the record within
549 operand 1 that has the same type as the PLACEHOLDER_EXPR in
551 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
553 /* Simple arithmetic. */
554 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
555 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
556 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
558 /* Division for integer result that rounds the quotient toward zero. */
559 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
561 /* Division for integer result that rounds the quotient toward infinity. */
562 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
564 /* Division for integer result that rounds toward minus infinity. */
565 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
567 /* Division for integer result that rounds toward nearest integer. */
568 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
570 /* Four kinds of remainder that go with the four kinds of division. */
571 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
572 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
573 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
574 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
576 /* Division for real result. */
577 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
579 /* Division which is not supposed to need rounding.
580 Used for pointer subtraction in C. */
581 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
583 /* Conversion of real to fixed point: four ways to round,
584 like the four ways to divide.
585 CONVERT_EXPR can also be used to convert a real to an integer,
586 and that is what is used in languages that do not have ways of
587 specifying which of these is wanted. Maybe these are not needed. */
588 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
589 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
590 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
591 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
593 /* Conversion of an integer to a real. */
594 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
596 /* Exponentiation. Operands may have any types;
597 constraints on value type are not known yet. */
598 DEFTREECODE (EXPON_EXPR, "expon_expr", '2', 2)
600 /* Unary negation. */
601 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
603 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
604 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
605 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
606 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
608 /* Shift operations for shift and rotate.
609 Shift means logical shift if done on an
610 unsigned type, arithmetic shift if done on a signed type.
611 The second operand is the number of bits to
612 shift by; it need not be the same type as the first operand and result. */
613 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
614 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
615 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
616 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
618 /* Bitwise operations. Operands have same mode as result. */
619 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
620 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
621 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
622 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
623 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
625 /* Combination of boolean values or of integers considered only
626 as zero or nonzero. ANDIF and ORIF allow the second operand
627 not to be computed if the value of the expression is determined
628 from the first operand. AND, OR, and XOR always compute the second
629 operand whether its value is needed or not (for side effects). */
630 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
631 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
632 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
633 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
634 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
635 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
637 /* Relational operators.
638 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
639 The others are allowed only for integer (or pointer or enumeral)
641 In all cases the operands will have the same type,
642 and the value is always the type used by the language for booleans. */
643 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
644 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
645 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
646 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
647 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
648 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
650 /* Additional relational operators for floating point unordered. */
651 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", '<', 2)
652 DEFTREECODE (ORDERED_EXPR, "ordered_expr", '<', 2)
654 /* These are equivalent to unordered or ... */
655 DEFTREECODE (UNLT_EXPR, "unlt_expr", '<', 2)
656 DEFTREECODE (UNLE_EXPR, "unle_expr", '<', 2)
657 DEFTREECODE (UNGT_EXPR, "ungt_expr", '<', 2)
658 DEFTREECODE (UNGE_EXPR, "unge_expr", '<', 2)
659 DEFTREECODE (UNEQ_EXPR, "uneq_expr", '<', 2)
661 /* Operations for Pascal sets. Not used now. */
662 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
663 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
664 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
665 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
667 /* Represents a conversion of type of a value.
668 All conversions, including implicit ones, must be
669 represented by CONVERT_EXPR or NOP_EXPR nodes. */
670 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
672 /* Represents a conversion expected to require no code to be generated. */
673 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
675 /* Value is same as argument, but guaranteed not an lvalue. */
676 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
678 /* Represents something we computed once and will use multiple times.
679 First operand is that expression. Second is the function decl
680 in which the SAVE_EXPR was created. The third operand is the RTL,
681 nonzero only after the expression has been computed. */
682 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
684 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
685 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
686 CALL_EXPRs and RTL_EXPRs, that are protected
687 from being evaluated more than once should be reset so that a new
688 expand_expr call of this expr will cause those to be re-evaluated.
689 This is useful when we want to reuse a tree in different places,
690 but where we must re-expand. */
691 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
693 /* Represents something whose RTL has already been expanded as a
694 sequence which should be emitted when this expression is expanded.
695 The first operand is the RTL to emit. It is the first of a chain
696 of insns. The second is the RTL expression for the result. Any
697 temporaries created during the building of the RTL_EXPR can be
698 reused once the RTL_EXPR has been expanded, with the exception of
700 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
702 /* & in C. Value is the address at which the operand's value resides.
703 Operand may have any mode. Result mode is Pmode. */
704 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
706 /* Non-lvalue reference or pointer to an object. */
707 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
709 /* Operand is a function constant; result is a function variable value
710 of typeEPmode. Used only for languages that need static chains. */
711 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
713 /* Given two real or integer operands of the same type,
714 returns a complex value of the corresponding complex type. */
715 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
717 /* Complex conjugate of operand. Used only on complex types. */
718 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
720 /* Used only on an operand of complex type, these return
721 a value of the corresponding component type. */
722 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
723 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
725 /* Nodes for ++ and -- in C.
726 The second arg is how much to increment or decrement by.
727 For a pointer, it would be the size of the object pointed to. */
728 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
729 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
730 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
731 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
733 /* Used to implement `va_arg'. */
734 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
736 /* Evaluate operand 1. If and only if an exception is thrown during
737 the evaluation of operand 1, evaluate operand 2.
739 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
740 evaluated unless an exception is throw. */
741 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
743 /* Evaluate the first operand.
744 The second operand is a a cleanup expression which is evaluated
745 before an exit (normal, exception, or jump out) from this expression.
747 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those
748 always copy the cleanup expression where needed. In contrast,
749 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine.
750 (At least conceptually; the optimizer could inline the cleanup
751 subroutine in the same way it could inline normal subroutines.)
752 TRY_FINALLY_EXPR should be used when the cleanup is actual statements
753 in the source of the current function (which people might want to
754 set breakpoints in). */
755 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
757 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
758 (Specifically, it is created by expand_expr, not front-ends.)
759 Operand 0 is the rtx for the start of the subroutine we need to call.
760 Operand 1 is the rtx for a variable in which to store the address
761 of where the subroutine should return to. */
762 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
764 /* Pop the top element off the dynamic handler chain. Used in
765 conjunction with setjmp/longjmp based exception handling, see
766 except.c for more details. This is meant to be used only by the
767 exception handling backend, expand_dhc_cleanup specifically. */
768 DEFTREECODE (POPDHC_EXPR, "popdhc_expr", 's', 0)
770 /* Pop the top element off the dynamic cleanup chain. Used in
771 conjunction with the exception handling. This is meant to be used
772 only by the exception handling backend. */
773 DEFTREECODE (POPDCC_EXPR, "popdcc_expr", 's', 0)
775 /* These types of expressions have no useful value,
776 and always have side effects. */
778 /* A label definition, encapsulated as a statement.
779 Operand 0 is the LABEL_DECL node for the label that appears here.
780 The type should be void and the value should be ignored. */
781 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
783 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
784 The type should be void and the value should be ignored. */
785 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
787 /* RETURN. Evaluates operand 0, then returns from the current function.
788 Presumably that operand is an assignment that stores into the
789 RESULT_DECL that hold the value to be returned.
790 The operand may be null.
791 The type should be void and the value should be ignored. */
792 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
794 /* Exit the inner most loop conditionally. Operand 0 is the condition.
795 The type should be void and the value should be ignored. */
796 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
798 /* A loop. Operand 0 is the body of the loop.
799 It must contain an EXIT_EXPR or is an infinite loop.
800 The type should be void and the value should be ignored. */
801 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
803 /* A labeled block. Operand 0 is the label that will be generated to
804 mark the end of the block.
805 Operand 1 is the labeled block body. */
806 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
808 /* Exit a labeled block, possibly returning a value. Operand 0 is a
809 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
811 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
813 /* Annotates a tree node (usually an expression) with source location
814 information: a file name (EXPR_WFL_FILENAME); a line number
815 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
816 expanded as the contained node (EXPR_WFL_NODE); a line note should
817 be emitted first if EXPR_WFL_EMIT_LINE_NOTE.
818 The third operand is only used in the Java front-end, and will
819 eventually be removed. */
820 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 3)
822 /* Switch expression.
823 Operand 0 is the expression used to perform the branch,
824 Operand 1 contains the case values. The way they're organized is
825 front-end implementation defined. */
826 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
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