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 /* C enums. The type node looks just like an INTEGER_TYPE node.
154 The symbols for the values of the enum type are defined by
155 CONST_DECL nodes, but the type does not point to them;
156 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
157 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
158 /* A forward reference `enum foo' when no enum named foo is defined yet
159 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
160 the TYPE_NAME field. If the type is later defined, the normal
161 fields are filled in.
162 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
163 treated similarly. */
164 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", 't', 0)
166 /* Pascal's boolean type (true or false are the only values);
167 no special fields needed. */
168 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", 't', 0)
170 /* CHAR in Pascal; not used in C.
171 No special fields needed. */
172 DEFTREECODE (CHAR_TYPE, "char_type", 't', 0)
174 /* All pointer-to-x types have code POINTER_TYPE.
175 The TREE_TYPE points to the node for the type pointed to. */
176 DEFTREECODE (POINTER_TYPE, "pointer_type", 't', 0)
178 /* An offset is a pointer relative to an object.
179 The TREE_TYPE field is the type of the object at the offset.
180 The TYPE_OFFSET_BASETYPE points to the node for the type of object
181 that the offset is relative to. */
182 DEFTREECODE (OFFSET_TYPE, "offset_type", 't', 0)
184 /* A reference is like a pointer except that it is coerced
185 automatically to the value it points to. Used in C++. */
186 DEFTREECODE (REFERENCE_TYPE, "reference_type", 't', 0)
188 /* METHOD_TYPE is the type of a function which takes an extra first
189 argument for "self", which is not present in the declared argument list.
190 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
191 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
192 includes the hidden argument for "self". */
193 DEFTREECODE (METHOD_TYPE, "method_type", 't', 0)
195 /* Used for Pascal; details not determined right now. */
196 DEFTREECODE (FILE_TYPE, "file_type", 't', 0)
198 /* Types of arrays. Special fields:
199 TREE_TYPE Type of an array element.
200 TYPE_DOMAIN Type to index by.
201 Its range of values specifies the array length.
202 TYPE_SEP Expression for units from one elt to the next.
203 TYPE_SEP_UNIT Number of bits in a unit for previous.
204 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
205 and holds the type to coerce a value of that array type to in C.
206 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
207 in languages (such as Chill) that make a distinction. */
208 /* Array types in C or Pascal */
209 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
211 /* Types of sets for Pascal. Special fields are the same as
212 in an array type. The target type is always a boolean type.
213 Used for both bitstrings and powersets in Chill;
214 TYPE_STRING_FLAG indicates a bitstring. */
215 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
217 /* Struct in C, or record in Pascal. */
219 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
220 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
221 types and enumerators.
222 A few may need to be added for Pascal. */
223 /* See the comment above, before ENUMERAL_TYPE, for how
224 forward references to struct tags are handled in C. */
225 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
227 /* Union in C. Like a struct, except that the offsets of the fields
229 /* See the comment above, before ENUMERAL_TYPE, for how
230 forward references to union tags are handled in C. */
231 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
233 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
234 in each FIELD_DECL determine what the union contains. The first
235 field whose DECL_QUALIFIER expression is true is deemed to occupy
237 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
239 /* Type of functions. Special fields:
240 TREE_TYPE type of value returned.
241 TYPE_ARG_TYPES list of types of arguments expected.
242 this list is made of TREE_LIST nodes.
243 Types of "Procedures" in languages where they are different from functions
244 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
245 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
247 /* This is a language-specific kind of type.
248 Its meaning is defined by the language front end.
249 layout_type does not know how to lay this out,
250 so the front-end must do so manually. */
251 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
255 /* First, the constants. */
257 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
258 32 bits each, giving us a 64 bit constant capability.
259 Note: constants of type char in Pascal are INTEGER_CST,
260 and so are pointer constants such as nil in Pascal or NULL in C.
261 `(int *) 1' in C also results in an INTEGER_CST. */
262 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 2)
264 /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
265 DEFTREECODE (REAL_CST, "real_cst", 'c', 3)
267 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
268 whose contents are other constant nodes.
269 Also there is TREE_CST_RTL. */
270 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 3)
272 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
273 Also there is TREE_CST_RTL. */
274 DEFTREECODE (STRING_CST, "string_cst", 'c', 3)
276 /* Declarations. All references to names are represented as ..._DECL nodes.
277 The decls in one binding context are chained through the TREE_CHAIN field.
278 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
279 (Some decls, most often labels, may have zero as the DECL_NAME).
280 DECL_CONTEXT points to the node representing the context in which
281 this declaration has its scope. For FIELD_DECLs, this is the
282 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
283 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
284 and CONST_DECL nodes, this points to either the FUNCTION_DECL for the
285 containing function, the RECORD_TYPE or UNION_TYPE for the containing
286 type, or NULL_TREE if the given decl has "file scope".
287 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
288 ..._DECL node of which this decl is an (inlined or template expanded)
290 The TREE_TYPE field holds the data type of the object, when relevant.
291 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
292 contents are the type whose name is being declared.
293 The DECL_ALIGN, DECL_SIZE,
294 and DECL_MODE fields exist in decl nodes just as in type nodes.
295 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
297 DECL_OFFSET holds an integer number of bits offset for the location.
298 DECL_VOFFSET holds an expression for a variable offset; it is
299 to be multiplied by DECL_VOFFSET_UNIT (an integer).
300 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
302 DECL_INITIAL holds the value to initialize a variable to,
303 or the value of a constant. For a function, it holds the body
304 (a node of type BLOCK representing the function's binding contour
305 and whose body contains the function's statements.) For a LABEL_DECL
306 in C, it is a flag, nonzero if the label's definition has been seen.
308 PARM_DECLs use a special field:
309 DECL_ARG_TYPE is the type in which the argument is actually
310 passed, which may be different from its type within the function.
312 FUNCTION_DECLs use four special fields:
313 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
314 DECL_RESULT holds a RESULT_DECL node for the value of a function,
315 or it is 0 for a function that returns no value.
316 (C functions returning void have zero here.)
317 The TREE_TYPE field is the type in which the result is actually
318 returned. This is usually the same as the return type of the
319 FUNCTION_DECL, but it may be a wider integer type because of
321 DECL_FUNCTION_CODE is a code number that is nonzero for
322 built-in functions. Its value is an enum built_in_function
323 that says which built-in function it is.
325 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
326 holds a line number. In some cases these can be the location of
327 a reference, if no definition has been seen.
329 DECL_ABSTRACT is non-zero if the decl represents an abstract instance
330 of a decl (i.e. one which is nested within an abstract instance of a
333 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
334 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
335 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
336 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
337 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
338 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
339 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
340 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
342 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
343 _DECLs, providing a hierarchy of names. */
344 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
346 /* References to storage. */
348 /* Value is structure or union component.
349 Operand 0 is the structure or union (an expression);
350 operand 1 is the field (a node of type FIELD_DECL). */
351 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
353 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
354 except the position is given explicitly rather than via a FIELD_DECL.
355 Operand 0 is the structure or union expression;
356 operand 1 is a tree giving the number of bits being referenced;
357 operand 2 is a tree giving the position of the first referenced bit.
358 The field can be either a signed or unsigned field;
359 TREE_UNSIGNED says which. */
360 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
362 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
363 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
365 /* Pascal `^` on a file. One operand, an expression for the file. */
366 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
368 /* Array indexing in languages other than C.
369 Operand 0 is the array; operand 1 is a (single) array index. */
370 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
372 /* Constructor: return an aggregate value made from specified components.
373 In C, this is used only for structure and array initializers.
374 Also used for SET_TYPE in Chill (and potentially Pascal).
375 The first "operand" is really a pointer to the RTL,
376 for constant constructors only.
377 The second operand is a list of component values
378 made out of a chain of TREE_LIST nodes.
381 The TREE_PURPOSE of each node is the corresponding index.
382 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
383 one for each index in the range. (If the corresponding TREE_VALUE
384 has side-effects, they are evaluated once for each element. Wrap the
385 value in a SAVE_EXPR if you want to evaluate side effects only once.)
387 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
388 The TREE_PURPOSE of each node is a FIELD_DECL.
391 The TREE_VALUE specifies a value (index) in the set that is true.
392 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
393 range of true values. Elements not listed are false (not in the set). */
394 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2)
396 /* The expression types are mostly straightforward, with the fourth argument
397 of DEFTREECODE saying how many operands there are.
398 Unless otherwise specified, the operands are expressions and the
399 types of all the operands and the expression must all be the same. */
401 /* Contains two expressions to compute, one followed by the other.
402 the first value is ignored. The second one's value is used. The
403 type of the first expression need not agree with the other types. */
404 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
406 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
407 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
409 /* Initialization expression. Operand 0 is the variable to initialize;
410 Operand 1 is the initializer. */
411 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
413 /* For TARGET_EXPR, operand 0 is the target of an initialization,
414 operand 1 is the initializer for the target,
415 and operand 2 is the cleanup for this node, if any.
416 and operand 3 is the saved initializer after this node has been
417 expanded once, this is so we can re-expand the tree later. */
418 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
420 /* Conditional expression ( ... ? ... : ... in C).
421 Operand 0 is the condition.
422 Operand 1 is the then-value.
423 Operand 2 is the else-value.
424 Operand 0 may be of any type, but the types of operands 1 and 2
425 must be the same and the same as the type of this expression. */
426 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
428 /* Declare local variables, including making RTL and allocating space.
429 Operand 0 is a chain of VAR_DECL nodes for the variables.
430 Operand 1 is the body, the expression to be computed using
431 the variables. The value of operand 1 becomes that of the BIND_EXPR.
432 Operand 2 is the BLOCK that corresponds to these bindings
433 for debugging purposes. If this BIND_EXPR is actually expanded,
434 that sets the TREE_USED flag in the BLOCK.
436 The BIND_EXPR is not responsible for informing parsers
437 about these variables. If the body is coming from the input file,
438 then the code that creates the BIND_EXPR is also responsible for
439 informing the parser of the variables.
441 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
442 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
443 If the BIND_EXPR should be output for debugging but will not be expanded,
444 set the TREE_USED flag by hand.
446 In order for the BIND_EXPR to be known at all, the code that creates it
447 must also install it as a subblock in the tree of BLOCK
448 nodes for the function. */
449 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
451 /* Function call. Operand 0 is the function.
452 Operand 1 is the argument list, a list of expressions
453 made out of a chain of TREE_LIST nodes.
454 There is no operand 2. That slot is used for the
455 CALL_EXPR_RTL macro (see preexpand_calls). */
456 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 3)
458 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
459 Operand 1 is the expression for "self".
460 Operand 2 is the list of explicit arguments. */
461 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
463 /* Specify a value to compute along with its corresponding cleanup.
464 Operand 0 argument is an expression whose value needs a cleanup.
465 Operand 1 is an RTL_EXPR which will eventually represent that value.
466 Operand 2 is the cleanup expression for the object.
467 The RTL_EXPR is used in this expression, which is how the expression
468 manages to act on the proper value.
469 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
470 it exists, otherwise it is the responsibility of the caller to manually
471 call expand_start_target_temps/expand_end_target_temps, as needed.
473 This differs from TRY_CATCH_EXPR in that operand 2 is always
474 evaluated when an exception isn't thrown when cleanups are run. */
475 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
477 /* Specify a cleanup point.
478 Operand 0 is an expression that may have cleanups. If it does, those
479 cleanups are executed after the expression is expanded.
481 Note that if the expression is a reference to storage, it is forced out
482 of memory before the cleanups are run. This is necessary to handle
483 cases where the cleanups modify the storage referenced; in the
484 expression 't.i', if 't' is a struct with an integer member 'i' and a
485 cleanup which modifies 'i', the value of the expression depends on
486 whether the cleanup is run before or after 't.i' is evaluated. When
487 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
488 the value of 't.i' must be forced out of memory.
490 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
491 BLKmode, because it will not be forced out of memory. */
492 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
494 /* The following two codes are used in languages that have types where
495 some field in an object of the type contains a value that is used in
496 the computation of another field's offset or size and/or the size of
497 the type. The positions and/or sizes of fields can vary from object
498 to object of the same type.
500 Record types with discriminants in Ada or schema types in Pascal are
501 examples of such types. This mechanism is also used to create "fat
502 pointers" for unconstrained array types in Ada; the fat pointer is a
503 structure one of whose fields is a pointer to the actual array type
504 and the other field is a pointer to a template, which is a structure
505 containing the bounds of the array. The bounds in the type pointed
506 to by the first field in the fat pointer refer to the values in the
509 When you wish to construct such a type you need "self-references"
510 that allow you to reference the object having this type from the
511 TYPE node, i.e. without having a variable instantiating this type.
513 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
514 a node that will later be replaced with the object being referenced.
515 Its type is that of the object and selects which object to use from
516 a chain of references (see below). No other slots are used in the
519 For example, if your type FOO is a RECORD_TYPE with a field BAR,
520 and you need the value of <variable>.BAR to calculate TYPE_SIZE
521 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
522 what contains both the expression we wish to
523 evaluate and an expression within which the object may be found.
524 The latter expression is the object itself in the simple case of an
525 Ada record with discriminant, but it can be the array in the case of
526 an unconstrained array.
528 In the latter case, we need the fat pointer, because the bounds of
529 the array can only be accessed from it. However, we rely here on the
530 fact that the expression for the array contains the dereference of
531 the fat pointer that obtained the array pointer.
533 Accordingly, when looking for the object to substitute in place of
534 a PLACEHOLDER_EXPR, we look down the first operand of the expression
535 passed as the second operand to WITH_RECORD_EXPR until we find
536 something of the desired type or reach a constant. */
538 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
539 evaluating this expression. The type of this expression is used to
540 find the record to replace it. */
541 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
543 /* Provide an expression that references a record to be used in place
544 of a PLACEHOLDER_EXPR. The record to be used is the record within
545 operand 1 that has the same type as the PLACEHOLDER_EXPR in
547 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
549 /* Simple arithmetic. */
550 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
551 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
552 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
554 /* Division for integer result that rounds the quotient toward zero. */
555 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
557 /* Division for integer result that rounds the quotient toward infinity. */
558 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
560 /* Division for integer result that rounds toward minus infinity. */
561 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
563 /* Division for integer result that rounds toward nearest integer. */
564 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
566 /* Four kinds of remainder that go with the four kinds of division. */
567 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
568 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
569 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
570 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
572 /* Division for real result. */
573 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
575 /* Division which is not supposed to need rounding.
576 Used for pointer subtraction in C. */
577 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
579 /* Conversion of real to fixed point: four ways to round,
580 like the four ways to divide.
581 CONVERT_EXPR can also be used to convert a real to an integer,
582 and that is what is used in languages that do not have ways of
583 specifying which of these is wanted. Maybe these are not needed. */
584 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
585 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
586 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
587 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
589 /* Conversion of an integer to a real. */
590 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
592 /* Exponentiation. Operands may have any types;
593 constraints on value type are not known yet. */
594 DEFTREECODE (EXPON_EXPR, "expon_expr", '2', 2)
596 /* Unary negation. */
597 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
599 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
600 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
601 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
602 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
604 /* Shift operations for shift and rotate.
605 Shift is supposed to mean logical shift if done on an
606 unsigned type, arithmetic shift on a signed type.
607 The second operand is the number of bits to
608 shift by; it need not be the same type as the first operand and result. */
609 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
610 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
611 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
612 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
614 /* Bitwise operations. Operands have same mode as result. */
615 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
616 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
617 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
618 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
619 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
621 /* Combination of boolean values or of integers considered only
622 as zero or nonzero. ANDIF and ORIF allow the second operand
623 not to be computed if the value of the expression is determined
624 from the first operand. AND, OR, and XOR always compute the second
625 operand whether its value is needed or not (for side effects). */
626 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
627 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
628 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
629 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
630 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
631 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
633 /* Relational operators.
634 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
635 The others are allowed only for integer (or pointer or enumeral)
637 In all cases the operands will have the same type,
638 and the value is always the type used by the language for booleans. */
639 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
640 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
641 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
642 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
643 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
644 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
646 /* Additional relational operators for floating point unordered. */
647 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", '<', 2)
648 DEFTREECODE (ORDERED_EXPR, "ordered_expr", '<', 2)
650 /* These are equivalent to unordered or ... */
651 DEFTREECODE (UNLT_EXPR, "unlt_expr", '<', 2)
652 DEFTREECODE (UNLE_EXPR, "unle_expr", '<', 2)
653 DEFTREECODE (UNGT_EXPR, "ungt_expr", '<', 2)
654 DEFTREECODE (UNGE_EXPR, "unge_expr", '<', 2)
655 DEFTREECODE (UNEQ_EXPR, "uneq_expr", '<', 2)
657 /* Operations for Pascal sets. Not used now. */
658 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
659 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
660 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
661 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
663 /* Represents a conversion of type of a value.
664 All conversions, including implicit ones, must be
665 represented by CONVERT_EXPR or NOP_EXPR nodes. */
666 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
668 /* Represents a conversion expected to require no code to be generated. */
669 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
671 /* Value is same as argument, but guaranteed not an lvalue. */
672 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
674 /* Represents something we computed once and will use multiple times.
675 First operand is that expression. Second is the function decl
676 in which the SAVE_EXPR was created. The third operand is the RTL,
677 nonzero only after the expression has been computed. */
678 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
680 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
681 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
682 CALL_EXPRs and RTL_EXPRs, that are protected
683 from being evaluated more than once should be reset so that a new
684 expand_expr call of this expr will cause those to be re-evaluated.
685 This is useful when we want to reuse a tree in different places,
686 but where we must re-expand. */
687 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
689 /* Represents something whose RTL has already been expanded
690 as a sequence which should be emitted when this expression is expanded.
691 The first operand is the RTL to emit. It is the first of a chain of insns.
692 The second is the RTL expression for the result. */
693 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
695 /* & in C. Value is the address at which the operand's value resides.
696 Operand may have any mode. Result mode is Pmode. */
697 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
699 /* Non-lvalue reference or pointer to an object. */
700 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
702 /* Operand is a function constant; result is a function variable value
703 of typeEPmode. Used only for languages that need static chains. */
704 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
706 /* Given two real or integer operands of the same type,
707 returns a complex value of the corresponding complex type. */
708 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
710 /* Complex conjugate of operand. Used only on complex types. */
711 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
713 /* Used only on an operand of complex type, these return
714 a value of the corresponding component type. */
715 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
716 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
718 /* Nodes for ++ and -- in C.
719 The second arg is how much to increment or decrement by.
720 For a pointer, it would be the size of the object pointed to. */
721 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
722 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
723 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
724 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
726 /* Used to implement `va_arg'. */
727 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
729 /* Evaluate operand 1. If and only if an exception is thrown during
730 the evaluation of operand 1, evaluate operand 2.
732 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
733 evaluated unless an exception is throw. */
734 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
736 /* Evaluate the first operand.
737 The second operand is a a cleanup expression which is evaluated
738 before an exit (normal, exception, or jump out) from this expression.
740 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those
741 always copy the cleanup expression where needed. In contrast,
742 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine.
743 (At least conceptually; the optimizer could inline the cleanup
744 subroutine in the same way it could inline normal subroutines.)
745 TRY_FINALLY_EXPR should be used when the cleanup is actual statements
746 in the source of the current function (which people might want to
747 set breakpoints in). */
748 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
750 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
751 (Specifically, it is created by expand_expr, not front-ends.)
752 Operand 0 is the rtx for the start of the subroutine we need to call.
753 Operand 1 is the rtx for a variable in which to store the address
754 of where the subroutine should return to. */
755 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
757 /* Pop the top element off the dynamic handler chain. Used in
758 conjunction with setjmp/longjmp based exception handling, see
759 except.c for more details. This is meant to be used only by the
760 exception handling backend, expand_dhc_cleanup specifically. */
761 DEFTREECODE (POPDHC_EXPR, "popdhc_expr", 's', 0)
763 /* Pop the top element off the dynamic cleanup chain. Used in
764 conjunction with the exception handling. This is meant to be used
765 only by the exception handling backend. */
766 DEFTREECODE (POPDCC_EXPR, "popdcc_expr", 's', 0)
768 /* These types of expressions have no useful value,
769 and always have side effects. */
771 /* A label definition, encapsulated as a statement.
772 Operand 0 is the LABEL_DECL node for the label that appears here.
773 The type should be void and the value should be ignored. */
774 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
776 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
777 The type should be void and the value should be ignored. */
778 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
780 /* RETURN. Evaluates operand 0, then returns from the current function.
781 Presumably that operand is an assignment that stores into the
782 RESULT_DECL that hold the value to be returned.
783 The operand may be null.
784 The type should be void and the value should be ignored. */
785 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
787 /* Exit the inner most loop conditionally. Operand 0 is the condition.
788 The type should be void and the value should be ignored. */
789 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
791 /* A loop. Operand 0 is the body of the loop.
792 It must contain an EXIT_EXPR or is an infinite loop.
793 The type should be void and the value should be ignored. */
794 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
796 /* A labeled block. Operand 0 is the label that will be generated to
797 mark the end of the block.
798 Operand 1 is the labeled block body. */
799 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
801 /* Exit a labeled block, possibly returning a value. Operand 0 is a
802 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
804 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
806 /* Annotates a tree node (usually an expression) with source location
807 information: a file name (EXPR_WFL_FILENAME); a line number
808 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
809 expanded as the contained node (EXPR_WFL_NODE); a line note should
810 be emitted first if EXPR_WFL_EMIT_LINE_NOTE.
811 The third operand is only used in the Java front-end, and will
812 eventually be removed. */
813 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 3)
815 /* Switch expression.
816 Operand 0 is the expression used to perform the branch,
817 Operand 1 contains the case values. The way they're organized is
818 front-end implementation defined. */
819 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
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