1 /* This file contains the definitions and documentation for the
2 tree codes used in GCC.
3 Copyright (C) 1987, 1988, 1993, 1995, 1997, 1998, 2000, 2001, 2004
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
24 /* For tcc_references, tcc_expression, tcc_comparison, tcc_unary,
25 tcc_binary, and tcc_statement nodes, which use struct tree_exp, the
26 4th element is the number of argument slots to allocate. This
27 determines the size of the tree node object. Other nodes use
28 different structures, and the size is determined by the tree_union
29 member structure; the 4th element should be zero. Languages that
30 define language-specific tcc_exceptional or tcc_constant codes must
31 define the tree_size langhook to say how big they are. */
33 /* Any erroneous construct is parsed into a node of this type.
34 This type of node is accepted without complaint in all contexts
35 by later parsing activities, to avoid multiple error messages
37 No fields in these nodes are used except the TREE_CODE. */
38 DEFTREECODE (ERROR_MARK, "error_mark", tcc_exceptional, 0)
40 /* Used to represent a name (such as, in the DECL_NAME of a decl node).
41 Internally it looks like a STRING_CST node.
42 There is only one IDENTIFIER_NODE ever made for any particular name.
43 Use `get_identifier' to get it (or create it, the first time). */
44 DEFTREECODE (IDENTIFIER_NODE, "identifier_node", tcc_exceptional, 0)
46 /* Has the TREE_VALUE and TREE_PURPOSE fields. */
47 /* These nodes are made into lists by chaining through the
48 TREE_CHAIN field. The elements of the list live in the
49 TREE_VALUE fields, while TREE_PURPOSE fields are occasionally
50 used as well to get the effect of Lisp association lists. */
51 DEFTREECODE (TREE_LIST, "tree_list", tcc_exceptional, 0)
53 /* These nodes contain an array of tree nodes. */
54 DEFTREECODE (TREE_VEC, "tree_vec", tcc_exceptional, 0)
56 /* A symbol binding block. These are arranged in a tree,
57 where the BLOCK_SUBBLOCKS field contains a chain of subblocks
58 chained through the BLOCK_CHAIN field.
59 BLOCK_SUPERCONTEXT points to the parent block.
60 For a block which represents the outermost scope of a function, it
61 points to the FUNCTION_DECL node.
62 BLOCK_VARS points to a chain of decl nodes.
63 BLOCK_TYPE_TAGS points to a chain of types which have their own names.
64 BLOCK_CHAIN points to the next BLOCK at the same level.
65 BLOCK_ABSTRACT_ORIGIN points to the original (abstract) tree node which
66 this block is an instance of, or else is NULL to indicate that this
67 block is not an instance of anything else. When non-NULL, the value
68 could either point to another BLOCK node or it could point to a
69 FUNCTION_DECL node (e.g. in the case of a block representing the
70 outermost scope of a particular inlining of a function).
71 BLOCK_ABSTRACT is nonzero if the block represents an abstract
72 instance of a block (i.e. one which is nested within an abstract
73 instance of an inline function).
74 TREE_ASM_WRITTEN is nonzero if the block was actually referenced
75 in the generated assembly. */
76 DEFTREECODE (BLOCK, "block", tcc_exceptional, 0)
78 /* Each data type is represented by a tree node whose code is one of
80 /* Each node that represents a data type has a component TYPE_SIZE
81 containing a tree that is an expression for the size in bits.
82 The TYPE_MODE contains the machine mode for values of this type.
83 The TYPE_POINTER_TO field contains a type for a pointer to this type,
84 or zero if no such has been created yet.
85 The TYPE_NEXT_VARIANT field is used to chain together types
86 that are variants made by type modifiers such as "const" and "volatile".
87 The TYPE_MAIN_VARIANT field, in any member of such a chain,
88 points to the start of the chain.
89 The TYPE_NONCOPIED_PARTS field is a list specifying which parts
90 of an object of this type should *not* be copied by assignment.
91 The TREE_VALUE of each is a FIELD_DECL that should not be
92 copied. The TREE_PURPOSE is an initial value for that field when
93 an object of this type is initialized via an INIT_EXPR. It may
94 be NULL if no special value is required. Even the things in this
95 list are copied if the right-hand side of an assignment is known
96 to be a complete object (rather than being, perhaps, a subobject
97 of some other object.) The determination of what constitutes a
98 complete object is done by fixed_type_p.
99 The TYPE_NAME field contains info on the name used in the program
100 for this type (for GDB symbol table output). It is either a
101 TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE
102 in the case of structs, unions or enums that are known with a tag,
103 or zero for types that have no special name.
104 The TYPE_CONTEXT for any sort of type which could have a name or
105 which could have named members (e.g. tagged types in C/C++) will
106 point to the node which represents the scope of the given type, or
107 will be NULL_TREE if the type has "file scope". For most types, this
108 will point to a BLOCK node or a FUNCTION_DECL node, but it could also
109 point to a FUNCTION_TYPE node (for types whose scope is limited to the
110 formal parameter list of some function type specification) or it
111 could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node
112 (for C++ "member" types).
113 For non-tagged-types, TYPE_CONTEXT need not be set to anything in
114 particular, since any type which is of some type category (e.g.
115 an array type or a function type) which cannot either have a name
116 itself or have named members doesn't really have a "scope" per se.
117 The TREE_CHAIN field is used as a forward-references to names for
118 ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes;
121 DEFTREECODE (VOID_TYPE, "void_type", tcc_type, 0)
122 /* The void type in C */
124 /* Integer types in all languages, including char in C.
125 Also used for sub-ranges of other discrete types.
126 Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive)
127 and TYPE_PRECISION (number of bits used by this type).
128 In the case of a subrange type in Pascal, the TREE_TYPE
129 of this will point at the supertype (another INTEGER_TYPE,
130 or an ENUMERAL_TYPE, CHAR_TYPE, or BOOLEAN_TYPE).
131 Otherwise, the TREE_TYPE is zero. */
132 DEFTREECODE (INTEGER_TYPE, "integer_type", tcc_type, 0)
134 /* C's float and double. Different floating types are distinguished
135 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */
136 DEFTREECODE (REAL_TYPE, "real_type", tcc_type, 0)
138 /* Complex number types. The TREE_TYPE field is the data type
139 of the real and imaginary parts. */
140 DEFTREECODE (COMPLEX_TYPE, "complex_type", tcc_type, 0)
142 /* Vector types. The TREE_TYPE field is the data type of the vector
143 elements. The TYPE_PRECISION field is the number of subparts of
145 DEFTREECODE (VECTOR_TYPE, "vector_type", tcc_type, 0)
147 /* C enums. The type node looks just like an INTEGER_TYPE node.
148 The symbols for the values of the enum type are defined by
149 CONST_DECL nodes, but the type does not point to them;
150 however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE
151 is a name and the TREE_VALUE is the value (an INTEGER_CST node). */
152 /* A forward reference `enum foo' when no enum named foo is defined yet
153 has zero (a null pointer) in its TYPE_SIZE. The tag name is in
154 the TYPE_NAME field. If the type is later defined, the normal
155 fields are filled in.
156 RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are
157 treated similarly. */
158 DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", tcc_type, 0)
160 /* Pascal's boolean type (true or false are the only values);
161 no special fields needed. */
162 DEFTREECODE (BOOLEAN_TYPE, "boolean_type", tcc_type, 0)
164 /* CHAR in Pascal; not used in C.
165 No special fields needed. */
166 DEFTREECODE (CHAR_TYPE, "char_type", tcc_type, 0)
168 /* All pointer-to-x types have code POINTER_TYPE.
169 The TREE_TYPE points to the node for the type pointed to. */
170 DEFTREECODE (POINTER_TYPE, "pointer_type", tcc_type, 0)
172 /* An offset is a pointer relative to an object.
173 The TREE_TYPE field is the type of the object at the offset.
174 The TYPE_OFFSET_BASETYPE points to the node for the type of object
175 that the offset is relative to. */
176 DEFTREECODE (OFFSET_TYPE, "offset_type", tcc_type, 0)
178 /* A reference is like a pointer except that it is coerced
179 automatically to the value it points to. Used in C++. */
180 DEFTREECODE (REFERENCE_TYPE, "reference_type", tcc_type, 0)
182 /* METHOD_TYPE is the type of a function which takes an extra first
183 argument for "self", which is not present in the declared argument list.
184 The TREE_TYPE is the return type of the method. The TYPE_METHOD_BASETYPE
185 is the type of "self". TYPE_ARG_TYPES is the real argument list, which
186 includes the hidden argument for "self". */
187 DEFTREECODE (METHOD_TYPE, "method_type", tcc_type, 0)
189 /* Used for Pascal; details not determined right now. */
190 DEFTREECODE (FILE_TYPE, "file_type", tcc_type, 0)
192 /* Types of arrays. Special fields:
193 TREE_TYPE Type of an array element.
194 TYPE_DOMAIN Type to index by.
195 Its range of values specifies the array length.
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", tcc_type, 0)
203 /* Struct in C, or record in Pascal. */
205 TYPE_FIELDS chain of FIELD_DECLs for the fields of the struct,
206 and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables,
207 types and enumerators.
208 A few may need to be added for Pascal. */
209 /* See the comment above, before ENUMERAL_TYPE, for how
210 forward references to struct tags are handled in C. */
211 DEFTREECODE (RECORD_TYPE, "record_type", tcc_type, 0)
213 /* Union in C. Like a struct, except that the offsets of the fields
215 /* See the comment above, before ENUMERAL_TYPE, for how
216 forward references to union tags are handled in C. */
217 DEFTREECODE (UNION_TYPE, "union_type", tcc_type, 0) /* C union type */
219 /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER
220 in each FIELD_DECL determine what the union contains. The first
221 field whose DECL_QUALIFIER expression is true is deemed to occupy
223 DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", tcc_type, 0)
225 /* Type of functions. Special fields:
226 TREE_TYPE type of value returned.
227 TYPE_ARG_TYPES list of types of arguments expected.
228 this list is made of TREE_LIST nodes.
229 Types of "Procedures" in languages where they are different from functions
230 have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type. */
231 DEFTREECODE (FUNCTION_TYPE, "function_type", tcc_type, 0)
233 /* This is a language-specific kind of type.
234 Its meaning is defined by the language front end.
235 layout_type does not know how to lay this out,
236 so the front-end must do so manually. */
237 DEFTREECODE (LANG_TYPE, "lang_type", tcc_type, 0)
241 /* First, the constants. */
243 /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields,
244 32 bits each, giving us a 64 bit constant capability. INTEGER_CST
245 nodes can be shared, and therefore should be considered read only.
246 They should be copied, before setting a flag such as
247 TREE_OVERFLOW. If an INTEGER_CST has TREE_OVERFLOW or
248 TREE_CONSTANT_OVERFLOW already set, it is known to be unique.
249 INTEGER_CST nodes are created for the integral types, for pointer
250 types and for vector and float types in some circumstances. */
251 DEFTREECODE (INTEGER_CST, "integer_cst", tcc_constant, 0)
253 /* Contents are in TREE_REAL_CST field. */
254 DEFTREECODE (REAL_CST, "real_cst", tcc_constant, 0)
256 /* Contents are in TREE_REALPART and TREE_IMAGPART fields,
257 whose contents are other constant nodes. */
258 DEFTREECODE (COMPLEX_CST, "complex_cst", tcc_constant, 0)
260 /* Contents are in TREE_VECTOR_CST_ELTS field. */
261 DEFTREECODE (VECTOR_CST, "vector_cst", tcc_constant, 0)
263 /* Contents are TREE_STRING_LENGTH and the actual contents of the string. */
264 DEFTREECODE (STRING_CST, "string_cst", tcc_constant, 0)
266 /* Declarations. All references to names are represented as ..._DECL
267 nodes. The decls in one binding context are chained through the
268 TREE_CHAIN field. Each DECL has a DECL_NAME field which contains
269 an IDENTIFIER_NODE. (Some decls, most often labels, may have zero
270 as the DECL_NAME). DECL_CONTEXT points to the node representing
271 the context in which this declaration has its scope. For
272 FIELD_DECLs, this is the RECORD_TYPE, UNION_TYPE, or
273 QUAL_UNION_TYPE node that the field is a member of. For VAR_DECL,
274 PARM_DECL, FUNCTION_DECL, LABEL_DECL, and CONST_DECL nodes, this
275 points to either the FUNCTION_DECL for the containing function, the
276 RECORD_TYPE or UNION_TYPE for the containing type, or NULL_TREE or
277 a TRANSLATION_UNIT_DECL if the given decl has "file scope".
278 DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract)
279 ..._DECL node of which this decl is an (inlined or template expanded)
281 The TREE_TYPE field holds the data type of the object, when relevant.
282 LABEL_DECLs have no data type. For TYPE_DECL, the TREE_TYPE field
283 contents are the type whose name is being declared.
284 The DECL_ALIGN, DECL_SIZE,
285 and DECL_MODE fields exist in decl nodes just as in type nodes.
286 They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes.
288 DECL_FIELD_BIT_OFFSET holds an integer number of bits offset for
289 the location. DECL_VOFFSET holds an expression for a variable
290 offset; it is to be multiplied by DECL_VOFFSET_UNIT (an integer).
291 These fields are relevant only in FIELD_DECLs and PARM_DECLs.
293 DECL_INITIAL holds the value to initialize a variable to,
294 or the value of a constant. For a function, it holds the body
295 (a node of type BLOCK representing the function's binding contour
296 and whose body contains the function's statements.) For a LABEL_DECL
297 in C, it is a flag, nonzero if the label's definition has been seen.
299 PARM_DECLs use a special field:
300 DECL_ARG_TYPE is the type in which the argument is actually
301 passed, which may be different from its type within the function.
303 FUNCTION_DECLs use four special fields:
304 DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments.
305 DECL_RESULT holds a RESULT_DECL node for the value of a function,
306 or it is 0 for a function that returns no value.
307 (C functions returning void have zero here.)
308 The TREE_TYPE field is the type in which the result is actually
309 returned. This is usually the same as the return type of the
310 FUNCTION_DECL, but it may be a wider integer type because of
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 nonzero 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", tcc_declaration, 0)
325 DEFTREECODE (LABEL_DECL, "label_decl", tcc_declaration, 0)
326 DEFTREECODE (CONST_DECL, "const_decl", tcc_declaration, 0)
327 DEFTREECODE (TYPE_DECL, "type_decl", tcc_declaration, 0)
328 DEFTREECODE (VAR_DECL, "var_decl", tcc_declaration, 0)
329 DEFTREECODE (PARM_DECL, "parm_decl", tcc_declaration, 0)
330 DEFTREECODE (RESULT_DECL, "result_decl", tcc_declaration, 0)
331 DEFTREECODE (FIELD_DECL, "field_decl", tcc_declaration, 0)
333 /* A namespace declaration. Namespaces appear in DECL_CONTEXT of other
334 _DECLs, providing a hierarchy of names. */
335 DEFTREECODE (NAMESPACE_DECL, "namespace_decl", tcc_declaration, 0)
337 /* A translation unit. This is not technically a declaration, since it
338 can't be looked up, but it's close enough. */
339 DEFTREECODE (TRANSLATION_UNIT_DECL, "translation_unit_decl",\
342 /* References to storage. */
344 /* Value is structure or union component.
345 Operand 0 is the structure or union (an expression).
346 Operand 1 is the field (a node of type FIELD_DECL).
347 Operand 2, if present, is the value of DECL_FIELD_OFFSET, measured
348 in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT. */
349 DEFTREECODE (COMPONENT_REF, "component_ref", tcc_reference, 3)
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 BIT_FIELD_REF_UNSIGNED says which. */
358 DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", tcc_reference, 3)
360 /* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */
361 DEFTREECODE (INDIRECT_REF, "indirect_ref", tcc_reference, 1)
363 /* Like above, but aligns the referenced address (i.e, if the address
364 in P is not aligned on TYPE_ALIGN boundary, then &(*P) != P). */
365 DEFTREECODE (ALIGN_INDIRECT_REF, "align_indirect_ref", tcc_reference, 1)
367 /* Same as INDIRECT_REF, but also specifies the alignment of the referenced
369 Operand 0 is the referenced address (a pointer);
370 Operand 1 is an INTEGER_CST which represents the alignment of the address,
371 or 0 if the alignment is unknown. */
372 DEFTREECODE (MISALIGNED_INDIRECT_REF, "misaligned_indirect_ref", tcc_reference, 2)
375 Operand 0 is the array; operand 1 is a (single) array index.
376 Operand 2, if present, is a copy of TYPE_MIN_VALUE of the index.
377 Operand 3, if present, is the element size, measured in units of
378 the alignment of the element type. */
379 DEFTREECODE (ARRAY_REF, "array_ref", tcc_reference, 4)
381 /* Likewise, except that the result is a range ("slice") of the array. The
382 starting index of the resulting array is taken from operand 1 and the size
383 of the range is taken from the type of the expression. */
384 DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", tcc_reference, 4)
386 /* Used to represent lookup of runtime type dependent data. Often this is
387 a reference to a vtable, but it needn't be. Operands are:
388 OBJ_TYPE_REF_EXPR: An expression that evaluates the value to use.
389 OBJ_TYPE_REF_OBJECT: Is the object on whose behalf the lookup is
390 being performed. Through this the optimizers may be able to statically
391 determine the dynamic type of the object.
392 OBJ_TYPE_REF_TOKEN: Something front-end specific used to resolve the
393 reference to something simpler, usually to the address of a DECL.
394 Never touched by the middle-end. Good choices would be either an
395 identifier or a vtable index. */
396 DEFTREECODE (OBJ_TYPE_REF, "obj_type_ref", tcc_expression, 3)
398 /* The exception object from the runtime. */
399 DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", tcc_expression, 0)
401 /* The filter object from the runtime. */
402 DEFTREECODE (FILTER_EXPR, "filter_expr", tcc_expression, 0)
404 /* Constructor: return an aggregate value made from specified components.
405 In C, this is used only for structure and array initializers.
406 The operand is a list of component values made out of a chain of
410 The TREE_PURPOSE of each node is the corresponding index.
411 If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
412 one for each index in the range. (If the corresponding TREE_VALUE
413 has side-effects, they are evaluated once for each element. Wrap the
414 value in a SAVE_EXPR if you want to evaluate side effects only once.)
416 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE:
417 The TREE_PURPOSE of each node is a FIELD_DECL. */
418 DEFTREECODE (CONSTRUCTOR, "constructor", tcc_expression, 1)
420 /* The expression types are mostly straightforward, with the fourth argument
421 of DEFTREECODE saying how many operands there are.
422 Unless otherwise specified, the operands are expressions and the
423 types of all the operands and the expression must all be the same. */
425 /* Contains two expressions to compute, one followed by the other.
426 the first value is ignored. The second one's value is used. The
427 type of the first expression need not agree with the other types. */
428 DEFTREECODE (COMPOUND_EXPR, "compound_expr", tcc_expression, 2)
430 /* Assignment expression. Operand 0 is the what to set; 1, the new value. */
431 DEFTREECODE (MODIFY_EXPR, "modify_expr", tcc_expression, 2)
433 /* Initialization expression. Operand 0 is the variable to initialize;
434 Operand 1 is the initializer. */
435 DEFTREECODE (INIT_EXPR, "init_expr", tcc_expression, 2)
437 /* For TARGET_EXPR, operand 0 is the target of an initialization,
438 operand 1 is the initializer for the target, which may be void
439 if simply expanding it initializes the target.
440 operand 2 is the cleanup for this node, if any.
441 operand 3 is the saved initializer after this node has been
442 expanded once; this is so we can re-expand the tree later. */
443 DEFTREECODE (TARGET_EXPR, "target_expr", tcc_expression, 4)
445 /* Conditional expression ( ... ? ... : ... in C).
446 Operand 0 is the condition.
447 Operand 1 is the then-value.
448 Operand 2 is the else-value.
449 Operand 0 may be of any type.
450 Operand 1 must have the same type as the entire expression, unless
451 it unconditionally throws an exception, in which case it should
452 have VOID_TYPE. The same constraints apply to operand 2. */
453 DEFTREECODE (COND_EXPR, "cond_expr", tcc_expression, 3)
455 /* Vector conditional expresion. It is like COND_EXPR, but with
458 A = VEC_COND_EXPR ( X < Y, B, C)
463 A[i] = X[i] < Y[i] ? B[i] : C[i];
465 DEFTREECODE (VEC_COND_EXPR, "vec_cond_expr", tcc_expression, 3)
467 /* Declare local variables, including making RTL and allocating space.
468 BIND_EXPR_VARS is a chain of VAR_DECL nodes for the variables.
469 BIND_EXPR_BODY is the body, the expression to be computed using
470 the variables. The value of operand 1 becomes that of the BIND_EXPR.
471 BIND_EXPR_BLOCK is the BLOCK that corresponds to these bindings
472 for debugging purposes. If this BIND_EXPR is actually expanded,
473 that sets the TREE_USED flag in the BLOCK.
475 The BIND_EXPR is not responsible for informing parsers
476 about these variables. If the body is coming from the input file,
477 then the code that creates the BIND_EXPR is also responsible for
478 informing the parser of the variables.
480 If the BIND_EXPR is ever expanded, its TREE_USED flag is set.
481 This tells the code for debugging symbol tables not to ignore the BIND_EXPR.
482 If the BIND_EXPR should be output for debugging but will not be expanded,
483 set the TREE_USED flag by hand.
485 In order for the BIND_EXPR to be known at all, the code that creates it
486 must also install it as a subblock in the tree of BLOCK
487 nodes for the function. */
488 DEFTREECODE (BIND_EXPR, "bind_expr", tcc_expression, 3)
490 /* Function call. Operand 0 is the function.
491 Operand 1 is the argument list, a list of expressions
492 made out of a chain of TREE_LIST nodes.
493 Operand 2 is the static chain argument, or NULL. */
494 DEFTREECODE (CALL_EXPR, "call_expr", tcc_expression, 3)
496 /* Specify a value to compute along with its corresponding cleanup.
497 Operand 0 is the cleanup expression.
498 The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR,
499 which must exist. This differs from TRY_CATCH_EXPR in that operand 1
500 is always evaluated when cleanups are run. */
501 DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", tcc_expression, 1)
503 /* Specify a cleanup point.
504 Operand 0 is an expression that may have cleanups. If it does, those
505 cleanups are executed after the expression is expanded.
507 Note that if the expression is a reference to storage, it is forced out
508 of memory before the cleanups are run. This is necessary to handle
509 cases where the cleanups modify the storage referenced; in the
510 expression 't.i', if 't' is a struct with an integer member 'i' and a
511 cleanup which modifies 'i', the value of the expression depends on
512 whether the cleanup is run before or after 't.i' is evaluated. When
513 expand_expr is run on 't.i', it returns a MEM. This is not good enough;
514 the value of 't.i' must be forced out of memory.
516 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have
517 BLKmode, because it will not be forced out of memory. */
518 DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", tcc_expression, 1)
520 /* The following two codes are used in languages that have types where
521 some field in an object of the type contains a value that is used in
522 the computation of another field's offset or size and/or the size of
523 the type. The positions and/or sizes of fields can vary from object
524 to object of the same type or even for one and the same object within
527 Record types with discriminants in Ada or schema types in Pascal are
528 examples of such types. This mechanism is also used to create "fat
529 pointers" for unconstrained array types in Ada; the fat pointer is a
530 structure one of whose fields is a pointer to the actual array type
531 and the other field is a pointer to a template, which is a structure
532 containing the bounds of the array. The bounds in the type pointed
533 to by the first field in the fat pointer refer to the values in the
536 When you wish to construct such a type you need "self-references"
537 that allow you to reference the object having this type from the
538 TYPE node, i.e. without having a variable instantiating this type.
540 Such a "self-references" is done using a PLACEHOLDER_EXPR. This is
541 a node that will later be replaced with the object being referenced.
542 Its type is that of the object and selects which object to use from
543 a chain of references (see below). No other slots are used in the
546 For example, if your type FOO is a RECORD_TYPE with a field BAR,
547 and you need the value of <variable>.BAR to calculate TYPE_SIZE
548 (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR
549 whose TREE_TYPE is FOO. Then construct your COMPONENT_REF with
550 the PLACEHOLDER_EXPR as the first operand (which has the correct
551 type). Later, when the size is needed in the program, the back-end
552 will find this PLACEHOLDER_EXPR and generate code to calculate the
553 actual size at run-time. In the following, we describe how this
556 When we wish to evaluate a size or offset, we check whether it contains a
557 PLACEHOLDER_EXPR. If it does, we call substitute_placeholder_in_expr
558 passing both that tree and an expression within which the object may be
559 found. The latter expression is the object itself in the simple case of
560 an Ada record with discriminant, but it can be the array in the case of an
563 In the latter case, we need the fat pointer, because the bounds of
564 the array can only be accessed from it. However, we rely here on the
565 fact that the expression for the array contains the dereference of
566 the fat pointer that obtained the array pointer. */
568 /* Denotes a record to later be substituted before evaluating this expression.
569 The type of this expression is used to find the record to replace it. */
570 DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", tcc_exceptional, 0)
572 /* Simple arithmetic. */
573 DEFTREECODE (PLUS_EXPR, "plus_expr", tcc_binary, 2)
574 DEFTREECODE (MINUS_EXPR, "minus_expr", tcc_binary, 2)
575 DEFTREECODE (MULT_EXPR, "mult_expr", tcc_binary, 2)
577 /* Division for integer result that rounds the quotient toward zero. */
578 DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", tcc_binary, 2)
580 /* Division for integer result that rounds the quotient toward infinity. */
581 DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", tcc_binary, 2)
583 /* Division for integer result that rounds toward minus infinity. */
584 DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", tcc_binary, 2)
586 /* Division for integer result that rounds toward nearest integer. */
587 DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", tcc_binary, 2)
589 /* Four kinds of remainder that go with the four kinds of division. */
590 DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", tcc_binary, 2)
591 DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", tcc_binary, 2)
592 DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", tcc_binary, 2)
593 DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", tcc_binary, 2)
595 /* Division for real result. */
596 DEFTREECODE (RDIV_EXPR, "rdiv_expr", tcc_binary, 2)
598 /* Division which is not supposed to need rounding.
599 Used for pointer subtraction in C. */
600 DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", tcc_binary, 2)
602 /* Conversion of real to fixed point: four ways to round,
603 like the four ways to divide.
604 CONVERT_EXPR can also be used to convert a real to an integer,
605 and that is what is used in languages that do not have ways of
606 specifying which of these is wanted. Maybe these are not needed. */
607 DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", tcc_unary, 1)
608 DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", tcc_unary, 1)
609 DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", tcc_unary, 1)
610 DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", tcc_unary, 1)
612 /* Conversion of an integer to a real. */
613 DEFTREECODE (FLOAT_EXPR, "float_expr", tcc_unary, 1)
615 /* Unary negation. */
616 DEFTREECODE (NEGATE_EXPR, "negate_expr", tcc_unary, 1)
618 DEFTREECODE (MIN_EXPR, "min_expr", tcc_binary, 2)
619 DEFTREECODE (MAX_EXPR, "max_expr", tcc_binary, 2)
621 /* Represents the absolute value of the operand.
623 An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE. The
624 operand of the ABS_EXPR must have the same type. */
625 DEFTREECODE (ABS_EXPR, "abs_expr", tcc_unary, 1)
627 /* Shift operations for shift and rotate.
628 Shift means logical shift if done on an
629 unsigned type, arithmetic shift if done on a signed type.
630 The second operand is the number of bits to
631 shift by; it need not be the same type as the first operand and result.
632 Note that the result is undefined if the second operand is larger
633 than the first operand's type size. */
634 DEFTREECODE (LSHIFT_EXPR, "lshift_expr", tcc_binary, 2)
635 DEFTREECODE (RSHIFT_EXPR, "rshift_expr", tcc_binary, 2)
636 DEFTREECODE (LROTATE_EXPR, "lrotate_expr", tcc_binary, 2)
637 DEFTREECODE (RROTATE_EXPR, "rrotate_expr", tcc_binary, 2)
639 /* Bitwise operations. Operands have same mode as result. */
640 DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", tcc_binary, 2)
641 DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", tcc_binary, 2)
642 DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", tcc_binary, 2)
643 DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", tcc_unary, 1)
645 /* ANDIF and ORIF allow the second operand not to be computed if the
646 value of the expression is determined from the first operand. AND,
647 OR, and XOR always compute the second operand whether its value is
648 needed or not (for side effects). The operand may have
649 BOOLEAN_TYPE or INTEGER_TYPE. In either case, the argument will be
650 either zero or one. For example, a TRUTH_NOT_EXPR will never have
651 an INTEGER_TYPE VAR_DECL as its argument; instead, a NE_EXPR will be
652 used to compare the VAR_DECL to zero, thereby obtaining a node with
653 value zero or one. */
654 DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", tcc_expression, 2)
655 DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", tcc_expression, 2)
656 DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", tcc_expression, 2)
657 DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", tcc_expression, 2)
658 DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", tcc_expression, 2)
659 DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", tcc_expression, 1)
661 /* Relational operators.
662 `EQ_EXPR' and `NE_EXPR' are allowed for any types.
663 The others are allowed only for integer (or pointer or enumeral)
665 In all cases the operands will have the same type,
666 and the value is always the type used by the language for booleans. */
667 DEFTREECODE (LT_EXPR, "lt_expr", tcc_comparison, 2)
668 DEFTREECODE (LE_EXPR, "le_expr", tcc_comparison, 2)
669 DEFTREECODE (GT_EXPR, "gt_expr", tcc_comparison, 2)
670 DEFTREECODE (GE_EXPR, "ge_expr", tcc_comparison, 2)
671 DEFTREECODE (EQ_EXPR, "eq_expr", tcc_comparison, 2)
672 DEFTREECODE (NE_EXPR, "ne_expr", tcc_comparison, 2)
674 /* Additional relational operators for floating point unordered. */
675 DEFTREECODE (UNORDERED_EXPR, "unordered_expr", tcc_comparison, 2)
676 DEFTREECODE (ORDERED_EXPR, "ordered_expr", tcc_comparison, 2)
678 /* These are equivalent to unordered or ... */
679 DEFTREECODE (UNLT_EXPR, "unlt_expr", tcc_comparison, 2)
680 DEFTREECODE (UNLE_EXPR, "unle_expr", tcc_comparison, 2)
681 DEFTREECODE (UNGT_EXPR, "ungt_expr", tcc_comparison, 2)
682 DEFTREECODE (UNGE_EXPR, "unge_expr", tcc_comparison, 2)
683 DEFTREECODE (UNEQ_EXPR, "uneq_expr", tcc_comparison, 2)
685 /* This is the reverse of uneq_expr. */
686 DEFTREECODE (LTGT_EXPR, "ltgt_expr", tcc_comparison, 2)
688 DEFTREECODE (RANGE_EXPR, "range_expr", tcc_binary, 2)
690 /* Represents a conversion of type of a value.
691 All conversions, including implicit ones, must be
692 represented by CONVERT_EXPR or NOP_EXPR nodes. */
693 DEFTREECODE (CONVERT_EXPR, "convert_expr", tcc_unary, 1)
695 /* Represents a conversion expected to require no code to be generated. */
696 DEFTREECODE (NOP_EXPR, "nop_expr", tcc_unary, 1)
698 /* Value is same as argument, but guaranteed not an lvalue. */
699 DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", tcc_unary, 1)
701 /* Represents viewing something of one type as being of a second type.
702 This corresponds to an "Unchecked Conversion" in Ada and roughly to
703 the idiom *(type2 *)&X in C. The only operand is the value to be
704 viewed as being of another type. It is undefined if the type of the
705 input and of the expression have different sizes.
707 This code may also be used within the LHS of a MODIFY_EXPR, in which
708 case no actual data motion may occur. TREE_ADDRESSABLE will be set in
709 this case and GCC must abort if it could not do the operation without
711 DEFTREECODE (VIEW_CONVERT_EXPR, "view_convert_expr", tcc_reference, 1)
713 /* Represents something we computed once and will use multiple times.
714 First operand is that expression. After it is evaluated once, it
715 will be replaced by the temporary variable that holds the value. */
716 DEFTREECODE (SAVE_EXPR, "save_expr", tcc_expression, 1)
718 /* & in C. Value is the address at which the operand's value resides.
719 Operand may have any mode. Result mode is Pmode. */
720 DEFTREECODE (ADDR_EXPR, "addr_expr", tcc_expression, 1)
722 /* Operand0 is a function constant; result is part N of a function
723 descriptor of type ptr_mode. */
724 DEFTREECODE (FDESC_EXPR, "fdesc_expr", tcc_expression, 2)
726 /* Given two real or integer operands of the same type,
727 returns a complex value of the corresponding complex type. */
728 DEFTREECODE (COMPLEX_EXPR, "complex_expr", tcc_binary, 2)
730 /* Complex conjugate of operand. Used only on complex types. */
731 DEFTREECODE (CONJ_EXPR, "conj_expr", tcc_unary, 1)
733 /* Used only on an operand of complex type, these return
734 a value of the corresponding component type. */
735 DEFTREECODE (REALPART_EXPR, "realpart_expr", tcc_reference, 1)
736 DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", tcc_reference, 1)
738 /* Nodes for ++ and -- in C.
739 The second arg is how much to increment or decrement by.
740 For a pointer, it would be the size of the object pointed to. */
741 DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", tcc_expression, 2)
742 DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", tcc_expression, 2)
743 DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", tcc_expression, 2)
744 DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", tcc_expression, 2)
746 /* Used to implement `va_arg'. */
747 DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", tcc_expression, 1)
749 /* Evaluate operand 1. If and only if an exception is thrown during
750 the evaluation of operand 1, evaluate operand 2.
752 This differs from TRY_FINALLY_EXPR in that operand 2 is not evaluated
753 on a normal or jump exit, only on an exception. */
754 DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", tcc_statement, 2)
756 /* Evaluate the first operand.
757 The second operand is a cleanup expression which is evaluated
758 on any exit (normal, exception, or jump out) from this expression. */
759 DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", tcc_statement, 2)
761 /* These types of expressions have no useful value,
762 and always have side effects. */
764 /* Used to represent a local declaration. The operand is DECL_EXPR_DECL. */
765 DEFTREECODE (DECL_EXPR, "decl_expr", tcc_statement, 1)
767 /* A label definition, encapsulated as a statement.
768 Operand 0 is the LABEL_DECL node for the label that appears here.
769 The type should be void and the value should be ignored. */
770 DEFTREECODE (LABEL_EXPR, "label_expr", tcc_statement, 1)
772 /* GOTO. Operand 0 is a LABEL_DECL node or an expression.
773 The type should be void and the value should be ignored. */
774 DEFTREECODE (GOTO_EXPR, "goto_expr", tcc_statement, 1)
776 /* RETURN. Evaluates operand 0, then returns from the current function.
777 Presumably that operand is an assignment that stores into the
778 RESULT_DECL that hold the value to be returned.
779 The operand may be null.
780 The type should be void and the value should be ignored. */
781 DEFTREECODE (RETURN_EXPR, "return_expr", tcc_statement, 1)
783 /* Exit the inner most loop conditionally. Operand 0 is the condition.
784 The type should be void and the value should be ignored. */
785 DEFTREECODE (EXIT_EXPR, "exit_expr", tcc_statement, 1)
787 /* A loop. Operand 0 is the body of the loop.
788 It must contain an EXIT_EXPR or is an infinite loop.
789 The type should be void and the value should be ignored. */
790 DEFTREECODE (LOOP_EXPR, "loop_expr", tcc_statement, 1)
792 /* Switch expression.
794 TREE_TYPE is the original type of the condition, before any
795 language required type conversions. It may be NULL, in which case
796 the original type and final types are assumed to be the same.
798 Operand 0 is the expression used to perform the branch,
799 Operand 1 is the body of the switch, which probably contains
800 CASE_LABEL_EXPRs. It may also be NULL, in which case operand 2
802 Operand 2 is either NULL_TREE or a TREE_VEC of the CASE_LABEL_EXPRs
804 DEFTREECODE (SWITCH_EXPR, "switch_expr", tcc_statement, 3)
806 /* Used to represent a case label. The operands are CASE_LOW and
807 CASE_HIGH, respectively. If CASE_LOW is NULL_TREE, the label is a
808 'default' label. If CASE_HIGH is NULL_TREE, the label is a normal case
809 label. CASE_LABEL is the corresponding LABEL_DECL. */
810 DEFTREECODE (CASE_LABEL_EXPR, "case_label_expr", tcc_statement, 3)
812 /* RESX. Resume execution after an exception. Operand 0 is a
813 number indicating the exception region that is being left. */
814 DEFTREECODE (RESX_EXPR, "resx_expr", tcc_statement, 1)
816 /* Used to represent an inline assembly statement. ASM_STRING returns a
817 STRING_CST for the instruction (e.g., "mov x, y"). ASM_OUTPUTS,
818 ASM_INPUTS, and ASM_CLOBBERS represent the outputs, inputs, and clobbers
819 for the statement. */
820 DEFTREECODE (ASM_EXPR, "asm_expr", tcc_statement, 4)
822 /* Variable references for SSA analysis. New SSA names are created every
823 time a variable is assigned a new value. The SSA builder uses SSA_NAME
824 nodes to implement SSA versioning. */
825 DEFTREECODE (SSA_NAME, "ssa_name", tcc_exceptional, 0)
827 /* SSA PHI operator. PHI_RESULT is the new SSA_NAME node created by
828 the PHI node. PHI_ARG_LENGTH is the number of arguments.
829 PHI_ARG_ELT returns the Ith tuple <ssa_name, edge> from the
830 argument list. Each tuple contains the incoming reaching
831 definition (SSA_NAME node) and the edge via which that definition
832 is coming through. */
833 DEFTREECODE (PHI_NODE, "phi_node", tcc_exceptional, 0)
835 /* Used to represent a typed exception handler. CATCH_TYPES is the type (or
836 list of types) handled, and CATCH_BODY is the code for the handler. */
837 DEFTREECODE (CATCH_EXPR, "catch_expr", tcc_statement, 2)
839 /* Used to represent an exception specification. EH_FILTER_TYPES is a list
840 of allowed types, and EH_FILTER_FAILURE is an expression to evaluate on
841 failure. EH_FILTER_MUST_NOT_THROW controls which range type to use when
843 DEFTREECODE (EH_FILTER_EXPR, "eh_filter_expr", tcc_statement, 2)
845 /* Node used for describing a property that is known at compile
847 DEFTREECODE (SCEV_KNOWN, "scev_known", tcc_expression, 0)
849 /* Node used for describing a property that is not known at compile
851 DEFTREECODE (SCEV_NOT_KNOWN, "scev_not_known", tcc_expression, 0)
853 /* Polynomial chains of recurrences.
854 Under the form: cr = {CHREC_LEFT (cr), +, CHREC_RIGHT (cr)}. */
855 DEFTREECODE (POLYNOMIAL_CHREC, "polynomial_chrec", tcc_expression, 3)
857 /* Used to chain children of container statements together.
858 Use the interface in tree-iterator.h to access this node. */
859 DEFTREECODE (STATEMENT_LIST, "statement_list", tcc_exceptional, 0)
861 /* Value handles. Artificial nodes to represent expressions in
862 partial redundancy elimination (tree-ssa-pre.c). These nodes are
863 used for expression canonicalization. If two expressions compute
864 the same value, they will be assigned the same value handle. */
865 DEFTREECODE (VALUE_HANDLE, "value_handle", tcc_exceptional, 0)
867 /* Base class information. Holds information about a class as a
868 baseclass of itself or another class. */
869 DEFTREECODE (TREE_BINFO, "tree_binfo", tcc_exceptional, 0)
871 /* Records the size for an expression of variable size type. This is
872 for use in contexts in which we are accessing the entire object,
873 such as for a function call, or block copy.
874 Operand 0 is the real expression.
875 Operand 1 is the size of the type in the expression. */
876 DEFTREECODE (WITH_SIZE_EXPR, "with_size_expr", tcc_expression, 2)
878 /* Extract elements from two input vectors Operand 0 and Operand 1
879 size VS, according to the offset OFF defined by Operand 2 as
881 If OFF > 0, the last VS - OFF elements of vector OP0 are concatenated to
882 the first OFF elements of the vector OP1.
883 If OFF == 0, then the returned vector is OP1.
884 On different targets OFF may take different forms; It can be an address, in
885 which case its low log2(VS)-1 bits define the offset, or it can be a mask
886 generated by the builtin targetm.vectorize.mask_for_load_builtin_decl. */
887 DEFTREECODE (REALIGN_LOAD_EXPR, "realign_load", tcc_expression, 3)