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 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 a 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_PURPOSE of each element is the offset of the part
102 and the TREE_VALUE is the size in bits of the part.
103 The TYPE_NAME field contains info on the name used in the program
104 for this type (for GDB symbol table output). It is either a
105 TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
106 in the case of structs, unions or enums that are known with a tag,
107 or zero for types that have no special name.
108 The TYPE_CONTEXT for any sort of type which could have a name or
109 which could have named members (e.g. tagged types in C/C++) will
110 point to the node which represents the scope of the given type, or
111 will be NULL_TREE if the type has "file scope". For most types, this
112 will point to a BLOCK node or a FUNCTION_DECL node, but it could also
113 point to a FUNCTION_TYPE node (for types whose scope is limited to the
114 formal parameter list of some function type specification) or it
115 could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
116 (for C++ "member" types).
117 For non-tagged-types, TYPE_CONTEXT need not be set to anything in
118 particular, since any type which is of some type category (e.g.
119 an array type or a function type) which cannot either have a name
120 itself or have named members doesn't really have a "scope" per se.
121 The TREE_CHAIN field is used as a forward-references to names for
122 ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
125 DEFTREECODE (VOID_TYPE, "void_type", "t", 0) /* The void type in C */
127 /* Integer types in all languages, including char in C.
128 Also used for sub-ranges of other discrete types.
129 Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
130 and TYPE_PRECISION (number of bits used by this type).
131 In the case of a subrange type in Pascal, the TREE_TYPE
132 of this will point at the supertype (another INTEGER_TYPE,
133 or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
134 Otherwise, the TREE_TYPE is zero. */
135 DEFTREECODE (INTEGER_TYPE, "integer_type", "t", 0)
137 /* C's float and double. Different floating types are distinguished
138 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
139 DEFTREECODE (REAL_TYPE, "real_type", "t", 0)
141 /* Complex number types. The TREE_TYPE field is the data type
142 of the real and imaginary parts. */
143 DEFTREECODE (COMPLEX_TYPE, "complex_type", "t", 0)
145 /* C enums. The type node looks just like an INTEGER_TYPE node.
146 The symbols for the values of the enum type are defined by
147 CONST_DECL nodes, but the type does not point to them;
148 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
149 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
150 /* A forward reference `enum foo' when no enum named foo is defined yet
151 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
152 the TYPE_NAME field. If the type is later defined, the normal
153 fields are filled in.
154 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
155 treated similarly. */
156 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", "t", 0)
158 /* Pascal's boolean type (true or false are the only values);
159 no special fields needed. */
160 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", "t", 0)
162 /* CHAR in Pascal; not used in C.
163 No special fields needed. */
164 DEFTREECODE (CHAR_TYPE, "char_type", "t", 0)
166 /* All pointer-to-x types have code POINTER_TYPE.
167 The TREE_TYPE points to the node for the type pointed to. */
168 DEFTREECODE (POINTER_TYPE, "pointer_type", "t", 0)
170 /* An offset is a pointer relative to an object.
171 The TREE_TYPE field is the type of the object at the offset.
172 The TYPE_OFFSET_BASETYPE points to the node for the type of object
173 that the offset is relative to. */
174 DEFTREECODE (OFFSET_TYPE, "offset_type", "t", 0)
176 /* A reference is like a pointer except that it is coerced
177 automatically to the value it points to. Used in C++. */
178 DEFTREECODE (REFERENCE_TYPE, "reference_type", "t", 0)
180 /* METHOD_TYPE is the type of a function which takes an extra first
181 argument for "self", which is not present in the declared argument list.
182 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
183 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
184 includes the hidden argument for "self". */
185 DEFTREECODE (METHOD_TYPE, "method_type", "t", 0)
187 /* Used for Pascal; details not determined right now. */
188 DEFTREECODE (FILE_TYPE, "file_type", "t", 0)
190 /* Types of arrays. Special fields:
191 TREE_TYPE Type of an array element.
192 TYPE_DOMAIN Type to index by.
193 Its range of values specifies the array length.
194 TYPE_SEP Expression for units from one elt to the next.
195 TYPE_SEP_UNIT Number of bits in a unit for previous.
196 The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero
197 and holds the type to coerce a value of that array type to in C.
198 TYPE_STRING_FLAG indicates a string (in contrast to an array of chars)
199 in languages (such as Chill) that make a distinction. */
200 /* Array types in C or Pascal */
201 DEFTREECODE (ARRAY_TYPE, "array_type", "t", 0)
203 /* Types of sets for Pascal. Special fields are the same as
204 in an array type. The target type is always a boolean type.
205 Used for both bitstrings and powersets in Chill;
206 TYPE_STRING_FLAG indicates a bitstring. */
207 DEFTREECODE (SET_TYPE, "set_type", "t", 0)
209 /* Struct in C, or record in Pascal. */
211 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct.
212 A few may need to be added for Pascal. */
213 /* See the comment above, before ENUMERAL_TYPE, for how
214 forward references to struct tags are handled in C. */
215 DEFTREECODE (RECORD_TYPE, "record_type", "t", 0)
217 /* Union in C. Like a struct, except that the offsets of the fields
219 /* See the comment above, before ENUMERAL_TYPE, for how
220 forward references to union tags are handled in C. */
221 DEFTREECODE (UNION_TYPE, "union_type", "t", 0) /* C union type */
223 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
224 in each FIELD_DECL determine what the union contains. The first
225 field whose DECL_QUALIFIER expression is true is deemed to occupy
227 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", "t", 0)
229 /* Type of functions. Special fields:
230 TREE_TYPE type of value returned.
231 TYPE_ARG_TYPES list of types of arguments expected.
232 this list is made of TREE_LIST nodes.
233 Types of "Procedures" in languages where they are different from functions
234 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
235 DEFTREECODE (FUNCTION_TYPE, "function_type", "t", 0)
237 /* This is a language-specific kind of type.
238 Its meaning is defined by the language front end.
239 layout_type does not know how to lay this out,
240 so the front-end must do so manually. */
241 DEFTREECODE (LANG_TYPE, "lang_type", "t", 0)
245 /* First, the constants. */
247 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
248 32 bits each, giving us a 64 bit constant capability.
249 Note: constants of type char in Pascal are INTEGER_CST,
250 and so are pointer constants such as nil in Pascal or NULL in C.
251 `(int *) 1' in C also results in an INTEGER_CST. */
252 DEFTREECODE (INTEGER_CST, "integer_cst", "c", 2)
254 /* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */
255 DEFTREECODE (REAL_CST, "real_cst", "c", 3)
257 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
258 whose contents are other constant nodes.
259 Also there is TREE_CST_RTL. */
260 DEFTREECODE (COMPLEX_CST, "complex_cst", "c", 3)
262 /* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
263 Also there is TREE_CST_RTL. */
264 DEFTREECODE (STRING_CST, "string_cst", "c", 3)
266 /* Declarations. All references to names are represented as ..._DECL nodes.
267 The decls in one binding context are chained through the TREE_CHAIN field.
268 Each DECL has a DECL_NAME field which contains an IDENTIFIER_NODE.
269 (Some decls, most often labels, may have zero as the DECL_NAME).
270 DECL_CONTEXT points to the node representing the context in which
271 this declaration has its scope. For FIELD_DECLs, this is the
272 RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE node that the field
273 is a member of. For VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL,
274 and CONST_DECL nodes, this points to the FUNCTION_DECL for the
275 containing function, or else yields NULL_TREE if the given decl
277 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
278 ..._DECL node of which this decl is an (inlined or template expanded)
280 The TREE_TYPE field holds the data type of the object, when relevant.
281 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
282 contents are the type whose name is being declared.
283 The DECL_ALIGN, DECL_SIZE,
284 and DECL_MODE fields exist in decl nodes just as in type nodes.
285 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
287 DECL_OFFSET holds an integer number of bits offset for the location.
288 DECL_VOFFSET holds an expression for a variable offset; it is
289 to be multiplied by DECL_VOFFSET_UNIT (an integer).
290 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
292 DECL_INITIAL holds the value to initialize a variable to,
293 or the value of a constant. For a function, it holds the body
294 (a node of type BLOCK representing the function's binding contour
295 and whose body contains the function's statements.) For a LABEL_DECL
296 in C, it is a flag, nonzero if the label's definition has been seen.
298 PARM_DECLs use a special field:
299 DECL_ARG_TYPE is the type in which the argument is actually
300 passed, which may be different from its type within the function.
302 FUNCTION_DECLs use four special fields:
303 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
304 DECL_RESULT holds a RESULT_DECL node for the value of a function,
305 or it is 0 for a function that returns no value.
306 (C functions returning void have zero here.)
307 DECL_RESULT_TYPE holds the type in which the result is actually
308 returned. This is usually the same as the type of DECL_RESULT,
309 but (1) it may be a wider integer type and
310 (2) it remains valid, for the sake of inlining, even after the
311 function's compilation is done.
312 DECL_FUNCTION_CODE is a code number that is nonzero for
313 built-in functions. Its value is an enum built_in_function
314 that says which built-in function it is.
316 DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE
317 holds a line number. In some cases these can be the location of
318 a reference, if no definition has been seen.
320 DECL_ABSTRACT is non-zero if the decl represents an abstract instance
321 of a decl (i.e. one which is nested within an abstract instance of a
324 DEFTREECODE (FUNCTION_DECL, "function_decl", "d", 0)
325 DEFTREECODE (LABEL_DECL, "label_decl", "d", 0)
326 DEFTREECODE (CONST_DECL, "const_decl", "d", 0)
327 DEFTREECODE (TYPE_DECL, "type_decl", "d", 0)
328 DEFTREECODE (VAR_DECL, "var_decl", "d", 0)
329 DEFTREECODE (PARM_DECL, "parm_decl", "d", 0)
330 DEFTREECODE (RESULT_DECL, "result_decl", "d", 0)
331 DEFTREECODE (FIELD_DECL, "field_decl", "d", 0)
333 /* References to storage. */
335 /* Value is structure or union component.
336 Operand 0 is the structure or union (an expression);
337 operand 1 is the field (a node of type FIELD_DECL). */
338 DEFTREECODE (COMPONENT_REF, "component_ref", "r", 2)
340 /* Reference to a group of bits within an object. Similar to COMPONENT_REF
341 except the position is given explicitly rather than via a FIELD_DECL.
342 Operand 0 is the structure or union expression;
343 operand 1 is a tree giving the number of bits being referenced;
344 operand 2 is a tree giving the position of the first referenced bit.
345 The field can be either a signed or unsigned field;
346 TREE_UNSIGNED says which. */
347 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", "r", 3)
349 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
350 DEFTREECODE (INDIRECT_REF, "indirect_ref", "r", 1)
352 /* Pascal `^` on a file. One operand, an expression for the file. */
353 DEFTREECODE (BUFFER_REF, "buffer_ref", "r", 1)
355 /* Array indexing in languages other than C.
356 Operand 0 is the array; operand 1 is a list of indices
357 stored as a chain of TREE_LIST nodes. */
358 DEFTREECODE (ARRAY_REF, "array_ref", "r", 2)
360 /* Constructor: return an aggregate value made from specified components.
361 In C, this is used only for structure and array initializers.
362 Also used for SET_TYPE in Chill (and potentially Pascal).
363 The first "operand" is really a pointer to the RTL,
364 for constant constructors only.
365 The second operand is a list of component values
366 made out of a chain of TREE_LIST nodes.
369 The TREE_PURPOSE of each node is the corresponding index.
370 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
371 one for each index in the range. (If the corresponding TREE_VALUE
372 has side-effects, they are evaluated once for each element. Wrap the
373 value in a SAVE_EXPR if you want to evaluate side effects only once.)
375 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
376 The TREE_PURPOSE of each node is a FIELD_DECL.
379 The TREE_VALUE specifies a value (index) in the set that is true.
380 If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
381 range of true values. Elements not listed are false (not in the set). */
382 DEFTREECODE (CONSTRUCTOR, "constructor", "e", 2)
384 /* The expression types are mostly straightforward, with the fourth argument
385 of DEFTREECODE saying how many operands there are.
386 Unless otherwise specified, the operands are expressions and the
387 types of all the operands and the expression must all be the same. */
389 /* Contains two expressions to compute, one followed by the other.
390 the first value is ignored. The second one's value is used. The
391 type of the first expression need not agree with the other types. */
392 DEFTREECODE (COMPOUND_EXPR, "compound_expr", "e", 2)
394 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
395 DEFTREECODE (MODIFY_EXPR, "modify_expr", "e", 2)
397 /* Initialization expression. Operand 0 is the variable to initialize;
398 Operand 1 is the initializer. */
399 DEFTREECODE (INIT_EXPR, "init_expr", "e", 2)
401 /* For TARGET_EXPR, operand 0 is the target of an initialization,
402 operand 1 is the initializer for the target,
403 and operand 2 is the cleanup for this node, if any.
404 and operand 3 is the saved initializer after this node has been
405 expanded once, this is so we can re-expand the tree later. */
406 DEFTREECODE (TARGET_EXPR, "target_expr", "e", 4)
408 /* Conditional expression ( ... ? ... : ... in C).
409 Operand 0 is the condition.
410 Operand 1 is the then-value.
411 Operand 2 is the else-value.
412 Operand 0 may be of any types, but the types of operands 1 and 2
413 must be the same and the same as the the of this expression. */
414 DEFTREECODE (COND_EXPR, "cond_expr", "e", 3)
416 /* Declare local variables, including making RTL and allocating space.
417 Operand 0 is a chain of VAR_DECL nodes for the variables.
418 Operand 1 is the body, the expression to be computed using
419 the variables. The value of operand 1 becomes that of the BIND_EXPR.
420 Operand 2 is the BLOCK that corresponds to these bindings
421 for debugging purposes. If this BIND_EXPR is actually expanded,
422 that sets the TREE_USED flag in the BLOCK.
424 The BIND_EXPR is not responsible for informing parsers
425 about these variables. If the body is coming from the input file,
426 then the code that creates the BIND_EXPR is also responsible for
427 informing the parser of the variables.
429 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
430 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
431 If the BIND_EXPR should be output for debugging but will not be expanded,
432 set the TREE_USED flag by hand.
434 In order for the BIND_EXPR to be known at all, the code that creates it
435 must also install it as a subblock in the tree of BLOCK
436 nodes for the function. */
437 DEFTREECODE (BIND_EXPR, "bind_expr", "e", 3)
439 /* Function call. Operand 0 is the function.
440 Operand 1 is the argument list, a list of expressions
441 made out of a chain of TREE_LIST nodes.
442 There is no operand 2. That slot is used for the
443 CALL_EXPR_RTL macro (see preexpand_calls). */
444 DEFTREECODE (CALL_EXPR, "call_expr", "e", 3)
446 /* Call a method. Operand 0 is the method, whose type is a METHOD_TYPE.
447 Operand 1 is the expression for "self".
448 Operand 2 is the list of explicit arguments. */
449 DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", "e", 4)
451 /* Specify a value to compute along with its corresponding cleanup.
452 Operand 0 argument is an expression whose value needs a cleanup.
453 Operand 1 is an RTL_EXPR which will eventually represent that value.
454 Operand 2 is the cleanup expression for the object.
455 The RTL_EXPR is used in this expression, which is how the expression
456 manages to act on the proper value.
457 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
458 it exists, otherwise it is the responsibility of the caller to manually
459 call expand_cleanups_to, as needed. */
460 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", "e", 3)
462 /* Specify a cleanup point.
463 Operand 0 is an expression that may have cleanups. If it does, those
464 cleanups are executed after the expression is expanded.
466 Note that if the expression is a reference to storage, it is forced out
467 of memory before the cleanups are run. This is necessary to handle
468 cases where the cleanups modify the storage referenced; in the
469 expression 't.i', if 't' is a struct with an integer member 'i' and a
470 cleanup which modifies 'i', the value of the expression depends on
471 whether the cleanup is run before or after 't.i' is evaluated. When
472 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
473 the value of 't.i' must be forced out of memory.
475 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
476 BLKmode, because it will not be forced out of memory. */
477 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", "e", 1)
479 /* The following two codes are used in languages that have types where
480 the position and/or sizes of fields vary from object to object of the
481 same type, i.e., where some other field in the object contains a value
482 that is used in the computation of another field's offset or size.
484 For example, a record type with a discriminant in Ada is such a type.
485 This mechanism is also used to create "fat pointers" for unconstrained
486 array types in Ada; the fat pointer is a structure one of whose fields is
487 a pointer to the actual array type and the other field is a pointer to a
488 template, which is a structure containing the bounds of the array. The
489 bounds in the type pointed to by the first field in the fat pointer refer
490 to the values in the template.
492 These "self-references" are doing using a PLACEHOLDER_EXPR. This is a
493 node that will later be replaced with the object being referenced. Its type
494 is that of the object and selects which object to use from a chain of
495 references (see below).
497 When we wish to evaluate a size or offset, we check it is contains a
498 placeholder. If it does, we construct a WITH_RECORD_EXPR that contains
499 both the expression we wish to evaluate and an expression within which the
500 object may be found. The latter expression is the object itself in
501 the simple case of an Ada record with discriminant, but it can be the
502 array in the case of an unconstrained array.
504 In the latter case, we need the fat pointer, because the bounds of the
505 array can only be accessed from it. However, we rely here on the fact that
506 the expression for the array contains the dereference of the fat pointer
507 that obtained the array pointer.
509 Accordingly, when looking for the object to substitute in place of
510 a PLACEHOLDER_EXPR, we look down the first operand of the expression
511 passed as the second operand to WITH_RECORD_EXPR until we find something
512 of the desired type or reach a constant. */
514 /* Denotes a record to later be supplied with a WITH_RECORD_EXPR when
515 evaluating this expression. The type of this expression is used to
516 find the record to replace it. */
517 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", "x", 0)
519 /* Provide an expression that references a record to be used in place
520 of a PLACEHOLDER_EXPR. The record to be used is the record within
521 operand 1 that has the same type as the PLACEHOLDER_EXPR in
523 DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", "e", 2)
525 /* Simple arithmetic. */
526 DEFTREECODE (PLUS_EXPR, "plus_expr", "2", 2)
527 DEFTREECODE (MINUS_EXPR, "minus_expr", "2", 2)
528 DEFTREECODE (MULT_EXPR, "mult_expr", "2", 2)
530 /* Division for integer result that rounds the quotient toward zero. */
531 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", "2", 2)
533 /* Division for integer result that rounds the quotient toward infinity. */
534 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", "2", 2)
536 /* Division for integer result that rounds toward minus infinity. */
537 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", "2", 2)
539 /* Division for integer result that rounds toward nearest integer. */
540 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", "2", 2)
542 /* Four kinds of remainder that go with the four kinds of division. */
543 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", "2", 2)
544 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", "2", 2)
545 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", "2", 2)
546 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", "2", 2)
548 /* Division for real result. */
549 DEFTREECODE (RDIV_EXPR, "rdiv_expr", "2", 2)
551 /* Division which is not supposed to need rounding.
552 Used for pointer subtraction in C. */
553 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", "2", 2)
555 /* Conversion of real to fixed point: four ways to round,
556 like the four ways to divide.
557 CONVERT_EXPR can also be used to convert a real to an integer,
558 and that is what is used in languages that do not have ways of
559 specifying which of these is wanted. Maybe these are not needed. */
560 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", "1", 1)
561 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", "1", 1)
562 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", "1", 1)
563 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", "1", 1)
565 /* Conversion of an integer to a real. */
566 DEFTREECODE (FLOAT_EXPR, "float_expr", "1", 1)
568 /* Exponentiation. Operands may have any types;
569 constraints on value type are not known yet. */
570 DEFTREECODE (EXPON_EXPR, "expon_expr", "2", 2)
572 /* Unary negation. */
573 DEFTREECODE (NEGATE_EXPR, "negate_expr", "1", 1)
575 DEFTREECODE (MIN_EXPR, "min_expr", "2", 2)
576 DEFTREECODE (MAX_EXPR, "max_expr", "2", 2)
577 DEFTREECODE (ABS_EXPR, "abs_expr", "1", 1)
578 DEFTREECODE (FFS_EXPR, "ffs_expr", "1", 1)
580 /* Shift operations for shift and rotate.
581 Shift is supposed to mean logical shift if done on an
582 unsigned type, arithmetic shift on a signed type.
583 The second operand is the number of bits to
584 shift by; it need not be the same type as the first operand and result. */
585 DEFTREECODE (LSHIFT_EXPR, "alshift_expr", "2", 2)
586 DEFTREECODE (RSHIFT_EXPR, "arshift_expr", "2", 2)
587 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", "2", 2)
588 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", "2", 2)
590 /* Bitwise operations. Operands have same mode as result. */
591 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", "2", 2)
592 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", "2", 2)
593 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", "2", 2)
594 DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", "2", 2)
595 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", "1", 1)
597 /* Combination of boolean values or of integers considered only
598 as zero or nonzero. ANDIF and ORIF allow the second operand
599 not to be computed if the value of the expression is determined
600 from the first operand. AND, OR, and XOR always compute the second
601 operand whether its value is needed or not (for side effects). */
602 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", "e", 2)
603 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", "e", 2)
604 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", "e", 2)
605 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", "e", 2)
606 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", "e", 2)
607 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", "e", 1)
609 /* Relational operators.
610 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
611 The others are allowed only for integer (or pointer or enumeral)
613 In all cases the operands will have the same type,
614 and the value is always the type used by the language for booleans. */
615 DEFTREECODE (LT_EXPR, "lt_expr", "<", 2)
616 DEFTREECODE (LE_EXPR, "le_expr", "<", 2)
617 DEFTREECODE (GT_EXPR, "gt_expr", "<", 2)
618 DEFTREECODE (GE_EXPR, "ge_expr", "<", 2)
619 DEFTREECODE (EQ_EXPR, "eq_expr", "<", 2)
620 DEFTREECODE (NE_EXPR, "ne_expr", "<", 2)
622 /* Operations for Pascal sets. Not used now. */
623 DEFTREECODE (IN_EXPR, "in_expr", "2", 2)
624 DEFTREECODE (SET_LE_EXPR, "set_le_expr", "<", 2)
625 DEFTREECODE (CARD_EXPR, "card_expr", "1", 1)
626 DEFTREECODE (RANGE_EXPR, "range_expr", "2", 2)
628 /* Represents a conversion of type of a value.
629 All conversions, including implicit ones, must be
630 represented by CONVERT_EXPR or NOP_EXPR nodes. */
631 DEFTREECODE (CONVERT_EXPR, "convert_expr", "1", 1)
633 /* Represents a conversion expected to require no code to be generated. */
634 DEFTREECODE (NOP_EXPR, "nop_expr", "1", 1)
636 /* Value is same as argument, but guaranteed not an lvalue. */
637 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", "1", 1)
639 /* Represents something we computed once and will use multiple times.
640 First operand is that expression. Second is the function decl
641 in which the SAVE_EXPR was created. The third operand is the RTL,
642 nonzero only after the expression has been computed. */
643 DEFTREECODE (SAVE_EXPR, "save_expr", "e", 3)
645 /* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we
646 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs,
647 CALL_EXPRs and RTL_EXPRs, that are protected
648 from being evaluated more than once should be reset so that a new
649 expand_expr call of this expr will cause those to be re-evaluated.
650 This is useful when we want to reuse a tree in different places,
651 but where we must re-expand. */
652 DEFTREECODE (UNSAVE_EXPR, "unsave_expr", "e", 1)
654 /* Represents something whose RTL has already been expanded
655 as a sequence which should be emitted when this expression is expanded.
656 The first operand is the RTL to emit. It is the first of a chain of insns.
657 The second is the RTL expression for the result. */
658 DEFTREECODE (RTL_EXPR, "rtl_expr", "e", 2)
660 /* & in C. Value is the address at which the operand's value resides.
661 Operand may have any mode. Result mode is Pmode. */
662 DEFTREECODE (ADDR_EXPR, "addr_expr", "e", 1)
664 /* Non-lvalue reference or pointer to an object. */
665 DEFTREECODE (REFERENCE_EXPR, "reference_expr", "e", 1)
667 /* Operand is a function constant; result is a function variable value
668 of typeEPmode. Used only for languages that need static chains. */
669 DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", "e", 1)
671 /* Given two real or integer operands of the same type,
672 returns a complex value of the corresponding complex type. */
673 DEFTREECODE (COMPLEX_EXPR, "complex_expr", "2", 2)
675 /* Complex conjugate of operand. Used only on complex types. */
676 DEFTREECODE (CONJ_EXPR, "conj_expr", "1", 1)
678 /* Used only on an operand of complex type, these return
679 a value of the corresponding component type. */
680 DEFTREECODE (REALPART_EXPR, "realpart_expr", "1", 1)
681 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", "1", 1)
683 /* Nodes for ++ and -- in C.
684 The second arg is how much to increment or decrement by.
685 For a pointer, it would be the size of the object pointed to. */
686 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", "e", 2)
687 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", "e", 2)
688 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", "e", 2)
689 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", "e", 2)
691 /* These types of expressions have no useful value,
692 and always have side effects. */
694 /* A label definition, encapsulated as a statement.
695 Operand 0 is the LABEL_DECL node for the label that appears here.
696 The type should be void and the value should be ignored. */
697 DEFTREECODE (LABEL_EXPR, "label_expr", "s", 1)
699 /* GOTO. Operand 0 is a LABEL_DECL node.
700 The type should be void and the value should be ignored. */
701 DEFTREECODE (GOTO_EXPR, "goto_expr", "s", 1)
703 /* RETURN. Evaluates operand 0, then returns from the current function.
704 Presumably that operand is an assignment that stores into the
705 RESULT_DECL that hold the value to be returned.
706 The operand may be null.
707 The type should be void and the value should be ignored. */
708 DEFTREECODE (RETURN_EXPR, "return_expr", "s", 1)
710 /* Exit the inner most loop conditionally. Operand 0 is the condition.
711 The type should be void and the value should be ignored. */
712 DEFTREECODE (EXIT_EXPR, "exit_expr", "s", 1)
714 /* A loop. Operand 0 is the body of the loop.
715 It must contain an EXIT_EXPR or is an infinite loop.
716 The type should be void and the value should be ignored. */
717 DEFTREECODE (LOOP_EXPR, "loop_expr", "s", 1)
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