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 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 DEFTREECODE (BLOCK, "block", 'b', 0)
88 /* Each data type is represented by a tree node whose code is one of
90 /* Each node that represents a data type has a component TYPE_SIZE
91 containing a tree that is an expression for the size in bits.
92 The TYPE_MODE contains the machine mode for values of this type.
93 The TYPE_POINTER_TO field contains a type for a pointer to this type,
94 or zero if no such has been created yet.
95 The TYPE_NEXT_VARIANT field is used to chain together types
96 that are variants made by type modifiers such as "const" and "volatile".
97 The TYPE_MAIN_VARIANT field, in any member of such a chain,
98 points to the start of the chain.
99 The TYPE_NONCOPIED_PARTS field is a list specifying which parts
100 of an object of this type should *not* be copied by assignment.
101 The TREE_VALUE of each is a FIELD_DECL that should not be
102 copied. The TREE_PURPOSE is an initial value for that field when
103 an object of this type is initialized via an INIT_EXPR. It may
104 be NULL if no special value is required. Even the things in this
105 list are copied if the right-hand side of an assignment is known
106 to be a complete object (rather than being, perhaps, a subobject
107 of some other object.) The determination of what constitutes a
108 complete object is done by fixed_type_p.
109 The TYPE_NAME field contains info on the name used in the program
110 for this type (for GDB symbol table output). It is either a
111 TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
112 in the case of structs, unions or enums that are known with a tag,
113 or zero for types that have no special name.
114 The TYPE_CONTEXT for any sort of type which could have a name or
115 which could have named members (e.g. tagged types in C/C++) will
116 point to the node which represents the scope of the given type, or
117 will be NULL_TREE if the type has "file scope". For most types, this
118 will point to a BLOCK node or a FUNCTION_DECL node, but it could also
119 point to a FUNCTION_TYPE node (for types whose scope is limited to the
120 formal parameter list of some function type specification) or it
121 could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
122 (for C++ "member" types).
123 For non-tagged-types, TYPE_CONTEXT need not be set to anything in
124 particular, since any type which is of some type category (e.g.
125 an array type or a function type) which cannot either have a name
126 itself or have named members doesn't really have a "scope" per se.
127 The TREE_CHAIN field is used as a forward-references to names for
128 ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
131 DEFTREECODE (VOID_TYPE, "void_type", 't', 0) /* The void type in C */
133 /* Integer types in all languages, including char in C.
134 Also used for sub-ranges of other discrete types.
135 Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
136 and TYPE_PRECISION (number of bits used by this type).
137 In the case of a subrange type in Pascal, the TREE_TYPE
138 of this will point at the supertype (another INTEGER_TYPE,
139 or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
140 Otherwise, the TREE_TYPE is zero. */
141 DEFTREECODE (INTEGER_TYPE, "integer_type", 't', 0)
143 /* C's float and double. Different floating types are distinguished
144 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
145 DEFTREECODE (REAL_TYPE, "real_type", 't', 0)
147 /* Complex number types. The TREE_TYPE field is the data type
148 of the real and imaginary parts. */
149 DEFTREECODE (COMPLEX_TYPE, "complex_type", 't', 0)
151 /* C enums. The type node looks just like an INTEGER_TYPE node.
152 The symbols for the values of the enum type are defined by
153 CONST_DECL nodes, but the type does not point to them;
154 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
155 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
156 /* A forward reference `enum foo' when no enum named foo is defined yet
157 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
158 the TYPE_NAME field. If the type is later defined, the normal
159 fields are filled in.
160 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
161 treated similarly. */
162 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", 't', 0)
164 /* Pascal's boolean type (true or false are the only values);
165 no special fields needed. */
166 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", 't', 0)
168 /* CHAR in Pascal; not used in C.
169 No special fields needed. */
170 DEFTREECODE (CHAR_TYPE, "char_type", 't', 0)
172 /* All pointer-to-x types have code POINTER_TYPE.
173 The TREE_TYPE points to the node for the type pointed to. */
174 DEFTREECODE (POINTER_TYPE, "pointer_type", 't', 0)
176 /* An offset is a pointer relative to an object.
177 The TREE_TYPE field is the type of the object at the offset.
178 The TYPE_OFFSET_BASETYPE points to the node for the type of object
179 that the offset is relative to. */
180 DEFTREECODE (OFFSET_TYPE, "offset_type", 't', 0)
182 /* A reference is like a pointer except that it is coerced
183 automatically to the value it points to. Used in C++. */
184 DEFTREECODE (REFERENCE_TYPE, "reference_type", 't', 0)
186 /* METHOD_TYPE is the type of a function which takes an extra first
187 argument for "self", which is not present in the declared argument list.
188 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
189 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
190 includes the hidden argument for "self". */
191 DEFTREECODE (METHOD_TYPE, "method_type", 't', 0)
193 /* Used for Pascal; details not determined right now. */
194 DEFTREECODE (FILE_TYPE, "file_type", 't', 0)
196 /* Types of arrays. Special fields:
197 TREE_TYPE Type of an array element.
198 TYPE_DOMAIN Type to index by.
199 Its range of values specifies the array length.
200 TYPE_SEP Expression for units from one elt to the next.
201 TYPE_SEP_UNIT Number of bits in a unit for previous.
202 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
203 and holds the type to coerce a value of that array type to in C.
204 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
205 in languages (such as Chill) that make a distinction. */
206 /* Array types in C or Pascal */
207 DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0)
209 /* Types of sets for Pascal. Special fields are the same as
210 in an array type. The target type is always a boolean type.
211 Used for both bitstrings and powersets in Chill;
212 TYPE_STRING_FLAG indicates a bitstring. */
213 DEFTREECODE (SET_TYPE, "set_type", 't', 0)
215 /* Struct in C, or record in Pascal. */
217 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
218 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
219 types and enumerators.
220 A few may need to be added for Pascal. */
221 /* See the comment above, before ENUMERAL_TYPE, for how
222 forward references to struct tags are handled in C. */
223 DEFTREECODE (RECORD_TYPE, "record_type", 't', 0)
225 /* Union in C. Like a struct, except that the offsets of the fields
227 /* See the comment above, before ENUMERAL_TYPE, for how
228 forward references to union tags are handled in C. */
229 DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */
231 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
232 in each FIELD_DECL determine what the union contains. The first
233 field whose DECL_QUALIFIER expression is true is deemed to occupy
235 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0)
237 /* Type of functions. Special fields:
238 TREE_TYPE type of value returned.
239 TYPE_ARG_TYPES list of types of arguments expected.
240 this list is made of TREE_LIST nodes.
241 Types of "Procedures" in languages where they are different from functions
242 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
243 DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0)
245 /* This is a language-specific kind of type.
246 Its meaning is defined by the language front end.
247 layout_type does not know how to lay this out,
248 so the front-end must do so manually. */
249 DEFTREECODE (LANG_TYPE, "lang_type", 't', 0)
253 /* First, the constants. */
255 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
256 32 bits each, giving us a 64 bit constant capability.
257 Note: constants of type char in Pascal are INTEGER_CST,
258 and so are pointer constants such as nil in Pascal or NULL in C.
259 `(int *) 1' in C also results in an INTEGER_CST. */
260 DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 2)
262 /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
263 DEFTREECODE (REAL_CST, "real_cst", 'c', 3)
265 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
266 whose contents are other constant nodes.
267 Also there is TREE_CST_RTL. */
268 DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 3)
270 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
271 Also there is TREE_CST_RTL. */
272 DEFTREECODE (STRING_CST, "string_cst", 'c', 3)
274 /* Declarations. All references to names are represented as ..._DECL nodes.
275 The decls in one binding context are chained through the TREE_CHAIN field.
276 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
277 (Some decls, most often labels, may have zero as the DECL_NAME).
278 DECL_CONTEXT points to the node representing the context in which
279 this declaration has its scope. For FIELD_DECLs, this is the
280 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
281 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
282 and CONST_DECL nodes, this points to either the FUNCTION_DECL for the
283 containing function, the RECORD_TYPE or UNION_TYPE for the containing
284 type, or NULL_TREE if the given decl has "file scope".
285 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
286 ..._DECL node of which this decl is an (inlined or template expanded)
288 The TREE_TYPE field holds the data type of the object, when relevant.
289 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
290 contents are the type whose name is being declared.
291 The DECL_ALIGN, DECL_SIZE,
292 and DECL_MODE fields exist in decl nodes just as in type nodes.
293 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
295 DECL_OFFSET holds an integer number of bits offset for the location.
296 DECL_VOFFSET holds an expression for a variable offset; it is
297 to be multiplied by DECL_VOFFSET_UNIT (an integer).
298 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
300 DECL_INITIAL holds the value to initialize a variable to,
301 or the value of a constant. For a function, it holds the body
302 (a node of type BLOCK representing the function's binding contour
303 and whose body contains the function's statements.) For a LABEL_DECL
304 in C, it is a flag, nonzero if the label's definition has been seen.
306 PARM_DECLs use a special field:
307 DECL_ARG_TYPE is the type in which the argument is actually
308 passed, which may be different from its type within the function.
310 FUNCTION_DECLs use four special fields:
311 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
312 DECL_RESULT holds a RESULT_DECL node for the value of a function,
313 or it is 0 for a function that returns no value.
314 (C functions returning void have zero here.)
315 The TREE_TYPE field is the type in which the result is actually
316 returned. This is usually the same as the return type of the
317 FUNCTION_DECL, but it may be a wider integer type because of
319 DECL_FUNCTION_CODE is a code number that is nonzero for
320 built-in functions. Its value is an enum built_in_function
321 that says which built-in function it is.
323 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
324 holds a line number. In some cases these can be the location of
325 a reference, if no definition has been seen.
327 DECL_ABSTRACT is non-zero if the decl represents an abstract instance
328 of a decl (i.e. one which is nested within an abstract instance of a
331 DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0)
332 DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0)
333 DEFTREECODE (CONST_DECL, "const_decl", 'd', 0)
334 DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0)
335 DEFTREECODE (VAR_DECL, "var_decl", 'd', 0)
336 DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0)
337 DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0)
338 DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0)
340 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
341 _DECLs, providing a hierarchy of names. */
342 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0)
344 /* References to storage. */
346 /* Value is structure or union component.
347 Operand 0 is the structure or union (an expression);
348 operand 1 is the field (a node of type FIELD_DECL). */
349 DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2)
351 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
352 except the position is given explicitly rather than via a FIELD_DECL.
353 Operand 0 is the structure or union expression;
354 operand 1 is a tree giving the number of bits being referenced;
355 operand 2 is a tree giving the position of the first referenced bit.
356 The field can be either a signed or unsigned field;
357 TREE_UNSIGNED says which. */
358 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3)
360 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
361 DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1)
363 /* Pascal `^` on a file. One operand, an expression for the file. */
364 DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1)
366 /* Array indexing in languages other than C.
367 Operand 0 is the array; operand 1 is a (single) array index. */
368 DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2)
370 /* Constructor: return an aggregate value made from specified components.
371 In C, this is used only for structure and array initializers.
372 Also used for SET_TYPE in Chill (and potentially Pascal).
373 The first "operand" is really a pointer to the RTL,
374 for constant constructors only.
375 The second operand is a list of component values
376 made out of a chain of TREE_LIST nodes.
379 The TREE_PURPOSE of each node is the corresponding index.
380 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
381 one for each index in the range. (If the corresponding TREE_VALUE
382 has side-effects, they are evaluated once for each element. Wrap the
383 value in a SAVE_EXPR if you want to evaluate side effects only once.)
385 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
386 The TREE_PURPOSE of each node is a FIELD_DECL.
389 The TREE_VALUE specifies a value (index) in the set that is true.
390 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
391 range of true values. Elements not listed are false (not in the set). */
392 DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2)
394 /* The expression types are mostly straightforward, with the fourth argument
395 of DEFTREECODE saying how many operands there are.
396 Unless otherwise specified, the operands are expressions and the
397 types of all the operands and the expression must all be the same. */
399 /* Contains two expressions to compute, one followed by the other.
400 the first value is ignored. The second one's value is used. The
401 type of the first expression need not agree with the other types. */
402 DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2)
404 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
405 DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2)
407 /* Initialization expression. Operand 0 is the variable to initialize;
408 Operand 1 is the initializer. */
409 DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2)
411 /* For TARGET_EXPR, operand 0 is the target of an initialization,
412 operand 1 is the initializer for the target,
413 and operand 2 is the cleanup for this node, if any.
414 and operand 3 is the saved initializer after this node has been
415 expanded once, this is so we can re-expand the tree later. */
416 DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4)
418 /* Conditional expression ( ... ? ... : ... in C).
419 Operand 0 is the condition.
420 Operand 1 is the then-value.
421 Operand 2 is the else-value.
422 Operand 0 may be of any type, but the types of operands 1 and 2
423 must be the same and the same as the type of this expression. */
424 DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3)
426 /* Declare local variables, including making RTL and allocating space.
427 Operand 0 is a chain of VAR_DECL nodes for the variables.
428 Operand 1 is the body, the expression to be computed using
429 the variables. The value of operand 1 becomes that of the BIND_EXPR.
430 Operand 2 is the BLOCK that corresponds to these bindings
431 for debugging purposes. If this BIND_EXPR is actually expanded,
432 that sets the TREE_USED flag in the BLOCK.
434 The BIND_EXPR is not responsible for informing parsers
435 about these variables. If the body is coming from the input file,
436 then the code that creates the BIND_EXPR is also responsible for
437 informing the parser of the variables.
439 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
440 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
441 If the BIND_EXPR should be output for debugging but will not be expanded,
442 set the TREE_USED flag by hand.
444 In order for the BIND_EXPR to be known at all, the code that creates it
445 must also install it as a subblock in the tree of BLOCK
446 nodes for the function. */
447 DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3)
449 /* Function call. Operand 0 is the function.
450 Operand 1 is the argument list, a list of expressions
451 made out of a chain of TREE_LIST nodes.
452 There is no operand 2. That slot is used for the
453 CALL_EXPR_RTL macro (see preexpand_calls). */
454 DEFTREECODE (CALL_EXPR, "call_expr", 'e', 3)
456 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
457 Operand 1 is the expression for "self".
458 Operand 2 is the list of explicit arguments. */
459 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4)
461 /* Specify a value to compute along with its corresponding cleanup.
462 Operand 0 argument is an expression whose value needs a cleanup.
463 Operand 1 is an RTL_EXPR which will eventually represent that value.
464 Operand 2 is the cleanup expression for the object.
465 The RTL_EXPR is used in this expression, which is how the expression
466 manages to act on the proper value.
467 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
468 it exists, otherwise it is the responsibility of the caller to manually
469 call expand_start_target_temps/expand_end_target_temps, as needed.
471 This differs from TRY_CATCH_EXPR in that operand 2 is always
472 evaluated when an exception isn't thrown when cleanups are run. */
473 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3)
475 /* Specify a cleanup point.
476 Operand 0 is an expression that may have cleanups. If it does, those
477 cleanups are executed after the expression is expanded.
479 Note that if the expression is a reference to storage, it is forced out
480 of memory before the cleanups are run. This is necessary to handle
481 cases where the cleanups modify the storage referenced; in the
482 expression 't.i', if 't' is a struct with an integer member 'i' and a
483 cleanup which modifies 'i', the value of the expression depends on
484 whether the cleanup is run before or after 't.i' is evaluated. When
485 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
486 the value of 't.i' must be forced out of memory.
488 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
489 BLKmode, because it will not be forced out of memory. */
490 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1)
492 /* The following two codes are used in languages that have types where
493 some field in an object of the type contains a value that is used in
494 the computation of another field's offset or size and/or the size of
495 the type. The positions and/or sizes of fields can vary from object
496 to object of the same type.
498 Record types with discriminants in Ada or schema types in Pascal are
499 examples of such types. This mechanism is also used to create "fat
500 pointers" for unconstrained array types in Ada; the fat pointer is a
501 structure one of whose fields is a pointer to the actual array type
502 and the other field is a pointer to a template, which is a structure
503 containing the bounds of the array. The bounds in the type pointed
504 to by the first field in the fat pointer refer to the values in the
507 When you wish to construct such a type you need "self-references"
508 that allow you to reference the object having this type from the
509 TYPE node, i.e. without having a variable instantiating this type.
511 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
512 a node that will later be replaced with the object being referenced.
513 Its type is that of the object and selects which object to use from
514 a chain of references (see below). No other slots are used in the
517 For example, if your type FOO is a RECORD_TYPE with a field BAR,
518 and you need the value of <variable>.BAR to calculate TYPE_SIZE
519 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
520 what contains both the expression we wish to
521 evaluate and an expression within which the object may be found.
522 The latter expression is the object itself in the simple case of an
523 Ada record with discriminant, but it can be the array in the case of
524 an unconstrained array.
526 In the latter case, we need the fat pointer, because the bounds of
527 the array can only be accessed from it. However, we rely here on the
528 fact that the expression for the array contains the dereference of
529 the fat pointer that obtained the array pointer.
531 Accordingly, when looking for the object to substitute in place of
532 a PLACEHOLDER_EXPR, we look down the first operand of the expression
533 passed as the second operand to WITH_RECORD_EXPR until we find
534 something of the desired type or reach a constant. */
536 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
537 evaluating this expression. The type of this expression is used to
538 find the record to replace it. */
539 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0)
541 /* Provide an expression that references a record to be used in place
542 of a PLACEHOLDER_EXPR. The record to be used is the record within
543 operand 1 that has the same type as the PLACEHOLDER_EXPR in
545 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2)
547 /* Simple arithmetic. */
548 DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2)
549 DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2)
550 DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2)
552 /* Division for integer result that rounds the quotient toward zero. */
553 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2)
555 /* Division for integer result that rounds the quotient toward infinity. */
556 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2)
558 /* Division for integer result that rounds toward minus infinity. */
559 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2)
561 /* Division for integer result that rounds toward nearest integer. */
562 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2)
564 /* Four kinds of remainder that go with the four kinds of division. */
565 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2)
566 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2)
567 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2)
568 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2)
570 /* Division for real result. */
571 DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2)
573 /* Division which is not supposed to need rounding.
574 Used for pointer subtraction in C. */
575 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2)
577 /* Conversion of real to fixed point: four ways to round,
578 like the four ways to divide.
579 CONVERT_EXPR can also be used to convert a real to an integer,
580 and that is what is used in languages that do not have ways of
581 specifying which of these is wanted. Maybe these are not needed. */
582 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1)
583 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1)
584 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1)
585 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1)
587 /* Conversion of an integer to a real. */
588 DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1)
590 /* Exponentiation. Operands may have any types;
591 constraints on value type are not known yet. */
592 DEFTREECODE (EXPON_EXPR, "expon_expr", '2', 2)
594 /* Unary negation. */
595 DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1)
597 DEFTREECODE (MIN_EXPR, "min_expr", '2', 2)
598 DEFTREECODE (MAX_EXPR, "max_expr", '2', 2)
599 DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1)
600 DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1)
602 /* Shift operations for shift and rotate.
603 Shift is supposed to mean logical shift if done on an
604 unsigned type, arithmetic shift on a signed type.
605 The second operand is the number of bits to
606 shift by; it need not be the same type as the first operand and result. */
607 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2)
608 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2)
609 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2)
610 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2)
612 /* Bitwise operations. Operands have same mode as result. */
613 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2)
614 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2)
615 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2)
616 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2)
617 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1)
619 /* Combination of boolean values or of integers considered only
620 as zero or nonzero. ANDIF and ORIF allow the second operand
621 not to be computed if the value of the expression is determined
622 from the first operand. AND, OR, and XOR always compute the second
623 operand whether its value is needed or not (for side effects). */
624 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2)
625 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2)
626 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2)
627 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2)
628 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2)
629 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1)
631 /* Relational operators.
632 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
633 The others are allowed only for integer (or pointer or enumeral)
635 In all cases the operands will have the same type,
636 and the value is always the type used by the language for booleans. */
637 DEFTREECODE (LT_EXPR, "lt_expr", '<', 2)
638 DEFTREECODE (LE_EXPR, "le_expr", '<', 2)
639 DEFTREECODE (GT_EXPR, "gt_expr", '<', 2)
640 DEFTREECODE (GE_EXPR, "ge_expr", '<', 2)
641 DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2)
642 DEFTREECODE (NE_EXPR, "ne_expr", '<', 2)
644 /* Operations for Pascal sets. Not used now. */
645 DEFTREECODE (IN_EXPR, "in_expr", '2', 2)
646 DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2)
647 DEFTREECODE (CARD_EXPR, "card_expr", '1', 1)
648 DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2)
650 /* Represents a conversion of type of a value.
651 All conversions, including implicit ones, must be
652 represented by CONVERT_EXPR or NOP_EXPR nodes. */
653 DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1)
655 /* Represents a conversion expected to require no code to be generated. */
656 DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1)
658 /* Value is same as argument, but guaranteed not an lvalue. */
659 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1)
661 /* Represents something we computed once and will use multiple times.
662 First operand is that expression. Second is the function decl
663 in which the SAVE_EXPR was created. The third operand is the RTL,
664 nonzero only after the expression has been computed. */
665 DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3)
667 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
668 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
669 CALL_EXPRs and RTL_EXPRs, that are protected
670 from being evaluated more than once should be reset so that a new
671 expand_expr call of this expr will cause those to be re-evaluated.
672 This is useful when we want to reuse a tree in different places,
673 but where we must re-expand. */
674 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1)
676 /* Represents something whose RTL has already been expanded
677 as a sequence which should be emitted when this expression is expanded.
678 The first operand is the RTL to emit. It is the first of a chain of insns.
679 The second is the RTL expression for the result. */
680 DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2)
682 /* & in C. Value is the address at which the operand's value resides.
683 Operand may have any mode. Result mode is Pmode. */
684 DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1)
686 /* Non-lvalue reference or pointer to an object. */
687 DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1)
689 /* Operand is a function constant; result is a function variable value
690 of typeEPmode. Used only for languages that need static chains. */
691 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1)
693 /* Given two real or integer operands of the same type,
694 returns a complex value of the corresponding complex type. */
695 DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2)
697 /* Complex conjugate of operand. Used only on complex types. */
698 DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1)
700 /* Used only on an operand of complex type, these return
701 a value of the corresponding component type. */
702 DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1)
703 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1)
705 /* Nodes for ++ and -- in C.
706 The second arg is how much to increment or decrement by.
707 For a pointer, it would be the size of the object pointed to. */
708 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2)
709 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2)
710 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2)
711 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2)
713 /* Used to implement `va_arg'. */
714 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", 'e', 1)
716 /* Evaluate operand 1. If and only if an exception is thrown during
717 the evaluation of operand 1, evaluate operand 2.
719 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never
720 evaluated unless an exception is throw. */
721 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2)
723 /* Evaluate the first operand.
724 The second operand is a a cleanup expression which is evaluated
725 before an exit (normal, exception, or jump out) from this expression.
727 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those
728 always copy the cleanup expression where needed. In contrast,
729 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine.
730 (At least conceptually; the optimizer could inline the cleanup
731 subroutine in the same way it could inline normal subroutines.)
732 TRY_FINALLY_EXPR should be used when the cleanup is actual statements
733 in the source of the current function (which people might want to
734 set breakpoints in). */
735 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2)
737 /* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR.
738 (Specifically, it is created by expand_expr, not front-ends.)
739 Operand 0 is the rtx for the start of the subroutine we need to call.
740 Operand 1 is the rtx for a variable in which to store the address
741 of where the subroutine should return to. */
742 DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2)
744 /* Pop the top element off the dynamic handler chain. Used in
745 conjunction with setjmp/longjmp based exception handling, see
746 except.c for more details. This is meant to be used only by the
747 exception handling backend, expand_dhc_cleanup specifically. */
748 DEFTREECODE (POPDHC_EXPR, "popdhc_expr", 's', 0)
750 /* Pop the top element off the dynamic cleanup chain. Used in
751 conjunction with the exception handling. This is meant to be used
752 only by the exception handling backend. */
753 DEFTREECODE (POPDCC_EXPR, "popdcc_expr", 's', 0)
755 /* These types of expressions have no useful value,
756 and always have side effects. */
758 /* A label definition, encapsulated as a statement.
759 Operand 0 is the LABEL_DECL node for the label that appears here.
760 The type should be void and the value should be ignored. */
761 DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1)
763 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
764 The type should be void and the value should be ignored. */
765 DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1)
767 /* RETURN. Evaluates operand 0, then returns from the current function.
768 Presumably that operand is an assignment that stores into the
769 RESULT_DECL that hold the value to be returned.
770 The operand may be null.
771 The type should be void and the value should be ignored. */
772 DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1)
774 /* Exit the inner most loop conditionally. Operand 0 is the condition.
775 The type should be void and the value should be ignored. */
776 DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1)
778 /* A loop. Operand 0 is the body of the loop.
779 It must contain an EXIT_EXPR or is an infinite loop.
780 The type should be void and the value should be ignored. */
781 DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1)
783 /* A labeled block. Operand 0 is the label that will be generated to
784 mark the end of the block.
785 Operand 1 is the labeled block body. */
786 DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2)
788 /* Exit a labeled block, possibly returning a value. Operand 0 is a
789 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It
791 DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2)
793 /* Annotates a tree node (usually an expression) with source location
794 information: a file name (EXPR_WFL_FILENAME); a line number
795 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is
796 expanded as the contained node (EXPR_WFL_NODE); a line note should
797 be emitted first if EXPR_WFL_EMIT_LINE_NOTE. */
798 DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 2)
800 /* Switch expression.
801 Operand 0 is the expression used to perform the branch,
802 Operand 1 contains the case values. The way they're organized is
803 front-end implementation defined. */
804 DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2)
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