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. 4 5This file is part of GNU CC. 6 7GNU CC is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as published by 9the Free Software Foundation; either version 2, or (at your option) 10any later version. 11 12GNU CC is distributed in the hope that it will be useful, 13but WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15GNU General Public License for more details. 16 17You should have received a copy of the GNU General Public License 18along with GNU CC; see the file COPYING. If not, write to 19the Free Software Foundation, 59 Temple Place - Suite 330, 20Boston, MA 02111-1307, USA. */ 21 22 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. */ 35 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. */ 39 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 43 for one error. 44 No fields in these nodes are used except the TREE_CODE. */ 45DEFTREECODE (ERROR_MARK, "error_mark", 'x', 0) 46 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). */ 51DEFTREECODE (IDENTIFIER_NODE, "identifier_node", 'x', -1) 52 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. */ 56DEFTREECODE (OP_IDENTIFIER, "op_identifier", 'x', 2) 57 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. */ 63DEFTREECODE (TREE_LIST, "tree_list", 'x', 2) 64 65/* These nodes contain an array of tree nodes. */ 66DEFTREECODE (TREE_VEC, "tree_vec", 'x', 2) 67 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). */ 86DEFTREECODE (BLOCK, "block", 'b', 0) 87 88/* Each data type is represented by a tree node whose code is one of 89 the following: */ 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; 129 see below. */ 130 131DEFTREECODE (VOID_TYPE, "void_type", 't', 0) /* The void type in C */ 132 133/* 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. */ 141DEFTREECODE (INTEGER_TYPE, "integer_type", 't', 0) 142 143/* C's float and double. Different floating types are distinguished 144 by machine mode and by the TYPE_SIZE and the TYPE_PRECISION. */ 145DEFTREECODE (REAL_TYPE, "real_type", 't', 0) 146 147/* Complex number types. The TREE_TYPE field is the data type 148 of the real and imaginary parts. */ 149DEFTREECODE (COMPLEX_TYPE, "complex_type", 't', 0) 150 151/* 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. */ 162DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", 't', 0) 163 164/* Pascal's boolean type (true or false are the only values); 165 no special fields needed. */ 166DEFTREECODE (BOOLEAN_TYPE, "boolean_type", 't', 0) 167 168/* CHAR in Pascal; not used in C. 169 No special fields needed. */ 170DEFTREECODE (CHAR_TYPE, "char_type", 't', 0) 171 172/* All pointer-to-x types have code POINTER_TYPE. 173 The TREE_TYPE points to the node for the type pointed to. */ 174DEFTREECODE (POINTER_TYPE, "pointer_type", 't', 0) 175 176/* 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. */ 180DEFTREECODE (OFFSET_TYPE, "offset_type", 't', 0) 181 182/* A reference is like a pointer except that it is coerced 183 automatically to the value it points to. Used in C++. */ 184DEFTREECODE (REFERENCE_TYPE, "reference_type", 't', 0) 185 186/* 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". */ 191DEFTREECODE (METHOD_TYPE, "method_type", 't', 0) 192 193/* Used for Pascal; details not determined right now. */ 194DEFTREECODE (FILE_TYPE, "file_type", 't', 0) 195 196/* 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 */ 207DEFTREECODE (ARRAY_TYPE, "array_type", 't', 0) 208 209/* 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. */ 213DEFTREECODE (SET_TYPE, "set_type", 't', 0) 214 215/* Struct in C, or record in Pascal. */ 216/* Special fields: 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. */ 223DEFTREECODE (RECORD_TYPE, "record_type", 't', 0) 224 225/* Union in C. Like a struct, except that the offsets of the fields 226 will all be zero. */ 227/* See the comment above, before ENUMERAL_TYPE, for how 228 forward references to union tags are handled in C. */ 229DEFTREECODE (UNION_TYPE, "union_type", 't', 0) /* C union type */ 230 231/* 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 234 the union. */ 235DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", 't', 0) 236 237/* 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. */ 243DEFTREECODE (FUNCTION_TYPE, "function_type", 't', 0) 244 245/* 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. */ 249DEFTREECODE (LANG_TYPE, "lang_type", 't', 0) 250 251/* Expressions */ 252 253/* First, the constants. */ 254 255/* 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. */ 260DEFTREECODE (INTEGER_CST, "integer_cst", 'c', 2) 261 262/* Contents are in TREE_REAL_CST field. Also there is TREE_CST_RTL. */ 263DEFTREECODE (REAL_CST, "real_cst", 'c', 3) 264 265/* Contents are in TREE_REALPART and TREE_IMAGPART fields, 266 whose contents are other constant nodes. 267 Also there is TREE_CST_RTL. */ 268DEFTREECODE (COMPLEX_CST, "complex_cst", 'c', 3) 269 270/* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields. 271 Also there is TREE_CST_RTL. */ 272DEFTREECODE (STRING_CST, "string_cst", 'c', 3) 273 274/* 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) 287 instance. 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. 294 295 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. 299 300 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. 305 306 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. 309 310 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 318 promotion. 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. 322 323 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. 326 327 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 329 inline function. */ 330 331DEFTREECODE (FUNCTION_DECL, "function_decl", 'd', 0) 332DEFTREECODE (LABEL_DECL, "label_decl", 'd', 0) 333DEFTREECODE (CONST_DECL, "const_decl", 'd', 0) 334DEFTREECODE (TYPE_DECL, "type_decl", 'd', 0) 335DEFTREECODE (VAR_DECL, "var_decl", 'd', 0) 336DEFTREECODE (PARM_DECL, "parm_decl", 'd', 0) 337DEFTREECODE (RESULT_DECL, "result_decl", 'd', 0) 338DEFTREECODE (FIELD_DECL, "field_decl", 'd', 0) 339 340/* A namespace declaration. Namespaces appear in DECL_CONTEXT of other 341 _DECLs, providing a hierarchy of names. */ 342DEFTREECODE (NAMESPACE_DECL, "namespace_decl", 'd', 0) 343 344/* References to storage. */ 345 346/* 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). */ 349DEFTREECODE (COMPONENT_REF, "component_ref", 'r', 2) 350 351/* 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. */ 358DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", 'r', 3) 359 360/* C unary `*' or Pascal `^'. One operand, an expression for a pointer. */ 361DEFTREECODE (INDIRECT_REF, "indirect_ref", 'r', 1) 362 363/* Pascal `^` on a file. One operand, an expression for the file. */ 364DEFTREECODE (BUFFER_REF, "buffer_ref", 'r', 1) 365 366/* Array indexing in languages other than C. 367 Operand 0 is the array; operand 1 is a (single) array index. */ 368DEFTREECODE (ARRAY_REF, "array_ref", 'r', 2) 369 370/* 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. 377 378 For ARRAY_TYPE: 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.) 384 385 For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE: 386 The TREE_PURPOSE of each node is a FIELD_DECL. 387 388 For SET_TYPE: 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). */ 392DEFTREECODE (CONSTRUCTOR, "constructor", 'e', 2) 393 394/* 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. */ 398 399/* 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. */ 402DEFTREECODE (COMPOUND_EXPR, "compound_expr", 'e', 2) 403 404/* Assignment expression. Operand 0 is the what to set; 1, the new value. */ 405DEFTREECODE (MODIFY_EXPR, "modify_expr", 'e', 2) 406 407/* Initialization expression. Operand 0 is the variable to initialize; 408 Operand 1 is the initializer. */ 409DEFTREECODE (INIT_EXPR, "init_expr", 'e', 2) 410 411/* 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. */ 416DEFTREECODE (TARGET_EXPR, "target_expr", 'e', 4) 417 418/* 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. */ 424DEFTREECODE (COND_EXPR, "cond_expr", 'e', 3) 425 426/* 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. 433 434 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. 438 439 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. 443 444 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. */ 447DEFTREECODE (BIND_EXPR, "bind_expr", 'e', 3) 448 449/* 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). */ 454DEFTREECODE (CALL_EXPR, "call_expr", 'e', 3) 455 456/* 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. */ 459DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", 'e', 4) 460 461/* 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. 470 471 This differs from TRY_CATCH_EXPR in that operand 2 is always 472 evaluated when an exception isn't thrown when cleanups are run. */ 473DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", 'e', 3) 474 475/* 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. 478 479 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. 487 488 As a consequence, the operand of a CLEANUP_POINT_EXPR must not have 489 BLKmode, because it will not be forced out of memory. */ 490DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", 'e', 1) 491 492/* The following two codes are used in languages that have types where 493 the position and/or sizes of fields vary from object to object of the 494 same type, i.e., where some other field in the object contains a value 495 that is used in the computation of another field's offset or size. 496 497 For example, a record type with a discriminant in Ada is such a type. 498 This mechanism is also used to create "fat pointers" for unconstrained 499 array types in Ada; the fat pointer is a structure one of whose fields is 500 a pointer to the actual array type and the other field is a pointer to a 501 template, which is a structure containing the bounds of the array. The 502 bounds in the type pointed to by the first field in the fat pointer refer 503 to the values in the template. 504 505 These "self-references" are doing using a PLACEHOLDER_EXPR. This is a 506 node that will later be replaced with the object being referenced. Its type 507 is that of the object and selects which object to use from a chain of 508 references (see below). 509 510 When we wish to evaluate a size or offset, we check it is contains a 511 placeholder. If it does, we construct a WITH_RECORD_EXPR that contains 512 both the expression we wish to evaluate and an expression within which the 513 object may be found. The latter expression is the object itself in 514 the simple case of an Ada record with discriminant, but it can be the 515 array in the case of an unconstrained array. 516 517 In the latter case, we need the fat pointer, because the bounds of the 518 array can only be accessed from it. However, we rely here on the fact that 519 the expression for the array contains the dereference of the fat pointer 520 that obtained the array pointer. 521 522 Accordingly, when looking for the object to substitute in place of 523 a PLACEHOLDER_EXPR, we look down the first operand of the expression 524 passed as the second operand to WITH_RECORD_EXPR until we find something 525 of the desired type or reach a constant. */ 526 527/* Denotes a record to later be supplied with a WITH_RECORD_EXPR when 528 evaluating this expression. The type of this expression is used to 529 find the record to replace it. */ 530DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", 'x', 0) 531 532/* Provide an expression that references a record to be used in place 533 of a PLACEHOLDER_EXPR. The record to be used is the record within 534 operand 1 that has the same type as the PLACEHOLDER_EXPR in 535 operand 0. */ 536DEFTREECODE (WITH_RECORD_EXPR, "with_record_expr", 'e', 2) 537 538/* Simple arithmetic. */ 539DEFTREECODE (PLUS_EXPR, "plus_expr", '2', 2) 540DEFTREECODE (MINUS_EXPR, "minus_expr", '2', 2) 541DEFTREECODE (MULT_EXPR, "mult_expr", '2', 2) 542 543/* Division for integer result that rounds the quotient toward zero. */ 544DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", '2', 2) 545 546/* Division for integer result that rounds the quotient toward infinity. */ 547DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", '2', 2) 548 549/* Division for integer result that rounds toward minus infinity. */ 550DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", '2', 2) 551 552/* Division for integer result that rounds toward nearest integer. */ 553DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", '2', 2) 554 555/* Four kinds of remainder that go with the four kinds of division. */ 556DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", '2', 2) 557DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", '2', 2) 558DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", '2', 2) 559DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", '2', 2) 560 561/* Division for real result. */ 562DEFTREECODE (RDIV_EXPR, "rdiv_expr", '2', 2) 563 564/* Division which is not supposed to need rounding. 565 Used for pointer subtraction in C. */ 566DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", '2', 2) 567 568/* Conversion of real to fixed point: four ways to round, 569 like the four ways to divide. 570 CONVERT_EXPR can also be used to convert a real to an integer, 571 and that is what is used in languages that do not have ways of 572 specifying which of these is wanted. Maybe these are not needed. */ 573DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", '1', 1) 574DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", '1', 1) 575DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", '1', 1) 576DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", '1', 1) 577 578/* Conversion of an integer to a real. */ 579DEFTREECODE (FLOAT_EXPR, "float_expr", '1', 1) 580 581/* Exponentiation. Operands may have any types; 582 constraints on value type are not known yet. */ 583DEFTREECODE (EXPON_EXPR, "expon_expr", '2', 2) 584 585/* Unary negation. */ 586DEFTREECODE (NEGATE_EXPR, "negate_expr", '1', 1) 587 588DEFTREECODE (MIN_EXPR, "min_expr", '2', 2) 589DEFTREECODE (MAX_EXPR, "max_expr", '2', 2) 590DEFTREECODE (ABS_EXPR, "abs_expr", '1', 1) 591DEFTREECODE (FFS_EXPR, "ffs_expr", '1', 1) 592 593/* Shift operations for shift and rotate. 594 Shift is supposed to mean logical shift if done on an 595 unsigned type, arithmetic shift on a signed type. 596 The second operand is the number of bits to 597 shift by; it need not be the same type as the first operand and result. */ 598DEFTREECODE (LSHIFT_EXPR, "lshift_expr", '2', 2) 599DEFTREECODE (RSHIFT_EXPR, "rshift_expr", '2', 2) 600DEFTREECODE (LROTATE_EXPR, "lrotate_expr", '2', 2) 601DEFTREECODE (RROTATE_EXPR, "rrotate_expr", '2', 2) 602 603/* Bitwise operations. Operands have same mode as result. */ 604DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", '2', 2) 605DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", '2', 2) 606DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", '2', 2) 607DEFTREECODE (BIT_ANDTC_EXPR, "bit_andtc_expr", '2', 2) 608DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", '1', 1) 609 610/* Combination of boolean values or of integers considered only 611 as zero or nonzero. ANDIF and ORIF allow the second operand 612 not to be computed if the value of the expression is determined 613 from the first operand. AND, OR, and XOR always compute the second 614 operand whether its value is needed or not (for side effects). */ 615DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", 'e', 2) 616DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", 'e', 2) 617DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", 'e', 2) 618DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", 'e', 2) 619DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", 'e', 2) 620DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", 'e', 1) 621 622/* Relational operators. 623 `EQ_EXPR' and `NE_EXPR' are allowed for any types. 624 The others are allowed only for integer (or pointer or enumeral) 625 or real types. 626 In all cases the operands will have the same type, 627 and the value is always the type used by the language for booleans. */ 628DEFTREECODE (LT_EXPR, "lt_expr", '<', 2) 629DEFTREECODE (LE_EXPR, "le_expr", '<', 2) 630DEFTREECODE (GT_EXPR, "gt_expr", '<', 2) 631DEFTREECODE (GE_EXPR, "ge_expr", '<', 2) 632DEFTREECODE (EQ_EXPR, "eq_expr", '<', 2) 633DEFTREECODE (NE_EXPR, "ne_expr", '<', 2) 634 635/* Operations for Pascal sets. Not used now. */ 636DEFTREECODE (IN_EXPR, "in_expr", '2', 2) 637DEFTREECODE (SET_LE_EXPR, "set_le_expr", '<', 2) 638DEFTREECODE (CARD_EXPR, "card_expr", '1', 1) 639DEFTREECODE (RANGE_EXPR, "range_expr", '2', 2) 640 641/* Represents a conversion of type of a value. 642 All conversions, including implicit ones, must be 643 represented by CONVERT_EXPR or NOP_EXPR nodes. */ 644DEFTREECODE (CONVERT_EXPR, "convert_expr", '1', 1) 645 646/* Represents a conversion expected to require no code to be generated. */ 647DEFTREECODE (NOP_EXPR, "nop_expr", '1', 1) 648 649/* Value is same as argument, but guaranteed not an lvalue. */ 650DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", '1', 1) 651 652/* Represents something we computed once and will use multiple times. 653 First operand is that expression. Second is the function decl 654 in which the SAVE_EXPR was created. The third operand is the RTL, 655 nonzero only after the expression has been computed. */ 656DEFTREECODE (SAVE_EXPR, "save_expr", 'e', 3) 657 658/* For a UNSAVE_EXPR, operand 0 is the value to unsave. By unsave, we 659 mean that all _EXPRs such as TARGET_EXPRs, SAVE_EXPRs, 660 CALL_EXPRs and RTL_EXPRs, that are protected 661 from being evaluated more than once should be reset so that a new 662 expand_expr call of this expr will cause those to be re-evaluated. 663 This is useful when we want to reuse a tree in different places, 664 but where we must re-expand. */ 665DEFTREECODE (UNSAVE_EXPR, "unsave_expr", 'e', 1) 666 667/* Represents something whose RTL has already been expanded 668 as a sequence which should be emitted when this expression is expanded. 669 The first operand is the RTL to emit. It is the first of a chain of insns. 670 The second is the RTL expression for the result. */ 671DEFTREECODE (RTL_EXPR, "rtl_expr", 'e', 2) 672 673/* & in C. Value is the address at which the operand's value resides. 674 Operand may have any mode. Result mode is Pmode. */ 675DEFTREECODE (ADDR_EXPR, "addr_expr", 'e', 1) 676 677/* Non-lvalue reference or pointer to an object. */ 678DEFTREECODE (REFERENCE_EXPR, "reference_expr", 'e', 1) 679 680/* Operand is a function constant; result is a function variable value 681 of typeEPmode. Used only for languages that need static chains. */ 682DEFTREECODE (ENTRY_VALUE_EXPR, "entry_value_expr", 'e', 1) 683 684/* Given two real or integer operands of the same type, 685 returns a complex value of the corresponding complex type. */ 686DEFTREECODE (COMPLEX_EXPR, "complex_expr", '2', 2) 687 688/* Complex conjugate of operand. Used only on complex types. */ 689DEFTREECODE (CONJ_EXPR, "conj_expr", '1', 1) 690 691/* Used only on an operand of complex type, these return 692 a value of the corresponding component type. */ 693DEFTREECODE (REALPART_EXPR, "realpart_expr", '1', 1) 694DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", '1', 1) 695 696/* Nodes for ++ and -- in C. 697 The second arg is how much to increment or decrement by. 698 For a pointer, it would be the size of the object pointed to. */ 699DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", 'e', 2) 700DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", 'e', 2) 701DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", 'e', 2) 702DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", 'e', 2) 703 704/* Evaluate operand 1. If and only if an exception is thrown during 705 the evaluation of operand 1, evaluate operand 2. 706 707 This differs from WITH_CLEANUP_EXPR, in that operand 2 is never 708 evaluated unless an exception is throw. */ 709DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", 'e', 2) 710 711/* Evaluate the first operand. 712 The second operand is a a cleanup expression which is evaluated 713 before an exit (normal, exception, or jump out) from this expression. 714 715 Like a CLEANUP_POINT_EXPR/WITH_CLEANUP_EXPR combination, but those 716 always copy the cleanup expression where needed. In contrast, 717 TRY_FINALLY_EXPR generates a jump to a cleanup subroutine. 718 (At least conceptually; the optimizer could inline the cleanup 719 subroutine in the same way it could inline normal subroutines.) 720 TRY_FINALLY_EXPR should be used when the cleanup is actual statements 721 in the source of the current function (which people might want to 722 set breakpoints in). */ 723DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", 'e', 2) 724 725/* Used internally for cleanups in the implementation of TRY_FINALLY_EXPR. 726 (Specifically, it is created by expand_expr, not front-ends.) 727 Operand 0 is the rtx for the start of the subroutine we need to call. 728 Operand 1 is the rtx for a variable in which to store the address 729 of where the subroutine should return to. */ 730DEFTREECODE (GOTO_SUBROUTINE_EXPR, "goto_subroutine", 'e', 2) 731 732/* Pop the top element off the dynamic handler chain. Used in 733 conjunction with setjmp/longjmp based exception handling, see 734 except.c for more details. This is meant to be used only by the 735 exception handling backend, expand_dhc_cleanup specifically. */ 736DEFTREECODE (POPDHC_EXPR, "popdhc_expr", 's', 0) 737 738/* Pop the top element off the dynamic cleanup chain. Used in 739 conjunction with the exception handling. This is meant to be used 740 only by the exception handling backend. */ 741DEFTREECODE (POPDCC_EXPR, "popdcc_expr", 's', 0) 742 743/* These types of expressions have no useful value, 744 and always have side effects. */ 745 746/* A label definition, encapsulated as a statement. 747 Operand 0 is the LABEL_DECL node for the label that appears here. 748 The type should be void and the value should be ignored. */ 749DEFTREECODE (LABEL_EXPR, "label_expr", 's', 1) 750 751/* GOTO. Operand 0 is a LABEL_DECL node or an expression. 752 The type should be void and the value should be ignored. */ 753DEFTREECODE (GOTO_EXPR, "goto_expr", 's', 1) 754 755/* RETURN. Evaluates operand 0, then returns from the current function. 756 Presumably that operand is an assignment that stores into the 757 RESULT_DECL that hold the value to be returned. 758 The operand may be null. 759 The type should be void and the value should be ignored. */ 760DEFTREECODE (RETURN_EXPR, "return_expr", 's', 1) 761 762/* Exit the inner most loop conditionally. Operand 0 is the condition. 763 The type should be void and the value should be ignored. */ 764DEFTREECODE (EXIT_EXPR, "exit_expr", 's', 1) 765 766/* A loop. Operand 0 is the body of the loop. 767 It must contain an EXIT_EXPR or is an infinite loop. 768 The type should be void and the value should be ignored. */ 769DEFTREECODE (LOOP_EXPR, "loop_expr", 's', 1) 770 771/* A labeled block. Operand 0 is the label that will be generated to 772 mark the end of the block. 773 Operand 1 is the labeled block body. */ 774DEFTREECODE (LABELED_BLOCK_EXPR, "labeled_block_expr", 'e', 2) 775 776/* Exit a labeled block, possibly returning a value. Operand 0 is a 777 LABELED_BLOCK_EXPR to exit. Operand 1 is the value to return. It 778 may be left null. */ 779DEFTREECODE (EXIT_BLOCK_EXPR, "exit_block_expr", 'e', 2) 780 781/* Annotates a tree node (usually an expression) with source location 782 information: a file name (EXPR_WFL_FILENAME); a line number 783 (EXPR_WFL_LINENO); and column number (EXPR_WFL_COLNO). It is 784 expanded as the contained node (EXPR_WFL_NODE); a line note should 785 be emitted first if EXPR_WFL_EMIT_LINE_NOTE. */ 786DEFTREECODE (EXPR_WITH_FILE_LOCATION, "expr_with_file_location", 'e', 2) 787 788/* Switch expression. 789 Operand 0 is the expression used to perform the branch, 790 Operand 1 contains the case values. The way they're organized is 791 front-end implementation defined. */ 792DEFTREECODE (SWITCH_EXPR, "switch_expr", 'e', 2) 793/* 794Local variables: 795mode:c 796End: 797*/ 798