gcc/cp/cp-tree.def

   1 /* This file contains the definitions and documentation for the
   2    additional tree codes used in the GNU C++ compiler (see tree.def
   3    for the standard codes).
   4    Copyright (C) 1987-2017 Free Software Foundation, Inc.
   5    Hacked by Michael Tiemann (tiemann@cygnus.com)
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 3, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23
  24 /* An OFFSET_REF is used in two situations:
  25
  26    1. An expression of the form `A::m' where `A' is a class and `m' is
  27       a non-static member.  In this case, operand 0 will be a TYPE
  28       (corresponding to `A') and operand 1 will be a FIELD_DECL,
  29       BASELINK, or TEMPLATE_ID_EXPR (corresponding to `m').
  30
  31       The expression is a pointer-to-member if its address is taken,
  32       but simply denotes a member of the object if its address is not
  33       taken.
  34
  35       This form is only used during the parsing phase; once semantic
  36       analysis has taken place they are eliminated.
  37
  38    2. An expression of the form `x.*p'.  In this case, operand 0 will
  39       be an expression corresponding to `x' and operand 1 will be an
  40       expression with pointer-to-member type.  */
  41 DEFTREECODE (OFFSET_REF, "offset_ref", tcc_reference, 2)
  42
  43 /* A pointer-to-member constant.  For a pointer-to-member constant
  44    `X::Y' The PTRMEM_CST_CLASS is the RECORD_TYPE for `X' and the
  45    PTRMEM_CST_MEMBER is the _DECL for `Y'.  */
  46 DEFTREECODE (PTRMEM_CST, "ptrmem_cst", tcc_constant, 0)
  47
  48 /* For NEW_EXPR, operand 0 is the placement list.
  49    Operand 1 is the new-declarator.
  50    Operand 2 is the number of elements in the array.
  51    Operand 3 is the initializer.  */
  52 DEFTREECODE (NEW_EXPR, "nw_expr", tcc_expression, 4)
  53 DEFTREECODE (VEC_NEW_EXPR, "vec_nw_expr", tcc_expression, 3)
  54
  55 /* For DELETE_EXPR, operand 0 is the store to be destroyed.
  56    Operand 1 is the value to pass to the destroying function
  57    saying whether the store should be deallocated as well.  */
  58 DEFTREECODE (DELETE_EXPR, "dl_expr", tcc_expression, 2)
  59 DEFTREECODE (VEC_DELETE_EXPR, "vec_dl_expr", tcc_expression, 2)
  60
  61 /* Value is reference to particular overloaded class method.
  62    Operand 0 is the class, operand 1 is the field
  63    The COMPLEXITY field holds the class level (usually 0).  */
  64 DEFTREECODE (SCOPE_REF, "scope_ref", tcc_reference, 2)
  65
  66 /* When composing an object with a member, this is the result.
  67    Operand 0 is the object.  Operand 1 is the member (usually
  68    a dereferenced pointer to member).  */
  69 DEFTREECODE (MEMBER_REF, "member_ref", tcc_reference, 2)
  70
  71 /* Type conversion operator in C++.  TREE_TYPE is type that this
  72    operator converts to.  Operand is expression to be converted.  */
  73 DEFTREECODE (TYPE_EXPR, "type_expr", tcc_expression, 1)
  74
  75 /* AGGR_INIT_EXPRs have a variably-sized representation similar to
  76    that of CALL_EXPRs.  Operand 0 is an INTEGER_CST node containing the
  77    operand count, operand 1 is the function which performs initialization,
  78    operand 2 is the slot which was allocated for this expression, and
  79    the remaining operands are the arguments to the initialization function.  */
  80 DEFTREECODE (AGGR_INIT_EXPR, "aggr_init_expr", tcc_vl_exp, 3)
  81
  82 /* Initialization of an array from another array, expressed at a high level
  83    so that it works with TARGET_EXPR.  Operand 0 is the target, operand 1
  84    is the initializer.  */
  85 DEFTREECODE (VEC_INIT_EXPR, "vec_init_expr", tcc_expression, 2)
  86
  87 /* A throw expression.  operand 0 is the expression, if there was one,
  88    else it is NULL_TREE.  */
  89 DEFTREECODE (THROW_EXPR, "throw_expr", tcc_expression, 1)
  90
  91 /* An empty class object.  The TREE_TYPE gives the class type.  We use
  92    these to avoid actually creating instances of the empty classes.  */
  93 DEFTREECODE (EMPTY_CLASS_EXPR, "empty_class_expr", tcc_expression, 0)
  94
  95 /* A reference to a member function or member functions from a base
  96    class.  BASELINK_FUNCTIONS gives the FUNCTION_DECL,
  97    TEMPLATE_DECL, OVERLOAD, or TEMPLATE_ID_EXPR corresponding to the
  98    functions.  BASELINK_BINFO gives the base from which the functions
  99    come, i.e., the base to which the `this' pointer must be converted
 100    before the functions are called.  BASELINK_ACCESS_BINFO gives the
 101    base used to name the functions.
 102
 103    A BASELINK is an expression; the TREE_TYPE of the BASELINK gives
 104    the type of the expression.  This type is either a FUNCTION_TYPE,
 105    METHOD_TYPE, or `unknown_type_node' indicating that the function is
 106    overloaded.  */
 107 DEFTREECODE (BASELINK, "baselink", tcc_exceptional, 0)
 108
 109 /* Template definition.  The following fields have the specified uses,
 110    although there are other macros in cp-tree.h that should be used for
 111    accessing this data.
 112         DECL_ARGUMENTS          template parm vector
 113         DECL_TEMPLATE_INFO      template text &c
 114         DECL_VINDEX             list of instantiations already produced;
 115                                 only done for functions so far
 116    For class template:
 117         DECL_INITIAL            associated templates (methods &c)
 118         DECL_TEMPLATE_RESULT    null
 119    For non-class templates:
 120         TREE_TYPE               type of object to be constructed
 121         DECL_TEMPLATE_RESULT    decl for object to be created
 122                                 (e.g., FUNCTION_DECL with tmpl parms used)
 123  */
 124 DEFTREECODE (TEMPLATE_DECL, "template_decl", tcc_declaration, 0)
 125
 126 /* Index into a template parameter list.  The TEMPLATE_PARM_IDX gives
 127    the index (from 0) of the parameter, while the TEMPLATE_PARM_LEVEL
 128    gives the level (from 1) of the parameter.
 129
 130    Here's an example:
 131
 132    template <class T> // Index 0, Level 1.
 133    struct S
 134    {
 135       template <class U, // Index 0, Level 2.
 136                 class V> // Index 1, Level 2.
 137       void f();
 138    };
 139
 140    The DESCENDANTS will be a chain of TEMPLATE_PARM_INDEXs descended
 141    from this one.  The first descendant will have the same IDX, but
 142    its LEVEL will be one less.  The TREE_CHAIN field is used to chain
 143    together the descendants.  The TEMPLATE_PARM_DECL is the
 144    declaration of this parameter, either a TYPE_DECL or CONST_DECL.
 145    The TEMPLATE_PARM_ORIG_LEVEL is the LEVEL of the most distant
 146    parent, i.e., the LEVEL that the parameter originally had when it
 147    was declared.  For example, if we instantiate S<int>, we will have:
 148
 149    struct S<int>
 150    {
 151      template <class U, // Index 0, Level 1, Orig Level 2
 152                class V> // Index 1, Level 1, Orig Level 2
 153      void f();
 154    };
 155
 156    The LEVEL is the level of the parameter when we are worrying about
 157    the types of things; the ORIG_LEVEL is the level when we are
 158    worrying about instantiating things.  */
 159 DEFTREECODE (TEMPLATE_PARM_INDEX, "template_parm_index", tcc_exceptional, 0)
 160
 161 /* Index into a template parameter list for template template parameters.
 162    This parameter must be a type.  The TYPE_FIELDS value will be a
 163    TEMPLATE_PARM_INDEX.
 164
 165    It is used without template arguments like TT in C<TT>,
 166    TYPE_NAME is a TEMPLATE_DECL.  */
 167 DEFTREECODE (TEMPLATE_TEMPLATE_PARM, "template_template_parm", tcc_type, 0)
 168
 169 /* The ordering of the following codes is optimized for the checking
 170    macros in tree.h.  Changing the order will degrade the speed of the
 171    compiler.  TEMPLATE_TYPE_PARM, TYPENAME_TYPE, TYPEOF_TYPE,
 172    BOUND_TEMPLATE_TEMPLATE_PARM.  */
 173
 174 /* Index into a template parameter list.  This parameter must be a type.
 175    The type.values field will be a TEMPLATE_PARM_INDEX.  */
 176 DEFTREECODE (TEMPLATE_TYPE_PARM, "template_type_parm", tcc_type, 0)
 177
 178 /* A type designated by `typename T::t'.  TYPE_CONTEXT is `T',
 179    TYPE_NAME is an IDENTIFIER_NODE for `t'.  If the type was named via
 180    template-id, TYPENAME_TYPE_FULLNAME will hold the TEMPLATE_ID_EXPR.
 181    TREE_TYPE is always NULL.  */
 182 DEFTREECODE (TYPENAME_TYPE, "typename_type", tcc_type, 0)
 183
 184 /* A type designated by `__typeof (expr)'.  TYPEOF_TYPE_EXPR is the
 185    expression in question.  */
 186 DEFTREECODE (TYPEOF_TYPE, "typeof_type", tcc_type, 0)
 187
 188 /* Like TEMPLATE_TEMPLATE_PARM it is used with bound template arguments
 189    like TT<int>.
 190    In this case, TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO contains the
 191    template name and its bound arguments.  TYPE_NAME is a TYPE_DECL.  */
 192 DEFTREECODE (BOUND_TEMPLATE_TEMPLATE_PARM, "bound_template_template_parm",
 193              tcc_type, 0)
 194
 195 /* For template template argument of the form `T::template C'.
 196    TYPE_CONTEXT is `T', the template parameter dependent object.
 197    TYPE_NAME is an IDENTIFIER_NODE for `C', the member class template.  */
 198 DEFTREECODE (UNBOUND_CLASS_TEMPLATE, "unbound_class_template", tcc_type, 0)
 199
 200 /* A using declaration.  USING_DECL_SCOPE contains the specified
 201    scope.  In a variadic using-declaration, this is a TYPE_PACK_EXPANSION.
 202    In a member using decl, unless DECL_DEPENDENT_P is true,
 203    USING_DECL_DECLS contains the _DECL or OVERLOAD so named.  This is
 204    not an alias, but is later expanded into multiple aliases.  */
 205 DEFTREECODE (USING_DECL, "using_decl", tcc_declaration, 0)
 206
 207 /* A using directive. The operand is USING_STMT_NAMESPACE.  */
 208 DEFTREECODE (USING_STMT, "using_stmt", tcc_statement, 1)
 209
 210 /* An un-parsed default argument.  Holds a vector of input tokens and
 211    a vector of places where the argument was instantiated before
 212    parsing had occurred.  */
 213 DEFTREECODE (DEFAULT_ARG, "default_arg", tcc_exceptional, 0)
 214
 215 /* An uninstantiated/unevaluated noexcept-specification.  For the
 216    uninstantiated case, DEFERRED_NOEXCEPT_PATTERN is the pattern from the
 217    template, and DEFERRED_NOEXCEPT_ARGS are the template arguments to
 218    substitute into the pattern when needed.  For the unevaluated case,
 219    those slots are NULL_TREE and we use get_defaulted_eh_spec to find
 220    the exception-specification.  */
 221 DEFTREECODE (DEFERRED_NOEXCEPT, "deferred_noexcept", tcc_exceptional, 0)
 222
 223 /* A template-id, like foo<int>.  The first operand is the template.
 224    The second is NULL if there are no explicit arguments, or a
 225    TREE_VEC of arguments.  The template will be a FUNCTION_DECL,
 226    TEMPLATE_DECL, or an OVERLOAD.  If the template-id refers to a
 227    member template, the template may be an IDENTIFIER_NODE.  */
 228 DEFTREECODE (TEMPLATE_ID_EXPR, "template_id_expr", tcc_expression, 2)
 229
 230 /* One of a set of overloaded functions.  */
 231 DEFTREECODE (OVERLOAD, "overload", tcc_exceptional, 0)
 232
 233 /* A pseudo-destructor, of the form "OBJECT.~DESTRUCTOR" or
 234    "OBJECT.SCOPE::~DESTRUCTOR.  The first operand is the OBJECT.  The
 235    second operand (if non-NULL) is the SCOPE.  The third operand is
 236    the TYPE node corresponding to the DESTRUCTOR.  The type of the
 237    first operand will always be a scalar type.
 238
 239    The type of a PSEUDO_DTOR_EXPR is always "void", even though it can
 240    be used as if it were a zero-argument function.  We handle the
 241    function-call case specially, and giving it "void" type prevents it
 242    being used in expressions in ways that are not permitted.  */
 243 DEFTREECODE (PSEUDO_DTOR_EXPR, "pseudo_dtor_expr", tcc_expression, 3)
 244
 245 /* A whole bunch of tree codes for the initial, superficial parsing of
 246    templates.  */
 247 DEFTREECODE (MODOP_EXPR, "modop_expr", tcc_expression, 3)
 248 DEFTREECODE (CAST_EXPR, "cast_expr", tcc_unary, 1)
 249 DEFTREECODE (REINTERPRET_CAST_EXPR, "reinterpret_cast_expr", tcc_unary, 1)
 250 DEFTREECODE (CONST_CAST_EXPR, "const_cast_expr", tcc_unary, 1)
 251 DEFTREECODE (STATIC_CAST_EXPR, "static_cast_expr", tcc_unary, 1)
 252 DEFTREECODE (DYNAMIC_CAST_EXPR, "dynamic_cast_expr", tcc_unary, 1)
 253 DEFTREECODE (IMPLICIT_CONV_EXPR, "implicit_conv_expr", tcc_unary, 1)
 254 DEFTREECODE (DOTSTAR_EXPR, "dotstar_expr", tcc_expression, 2)
 255 DEFTREECODE (TYPEID_EXPR, "typeid_expr", tcc_expression, 1)
 256 DEFTREECODE (NOEXCEPT_EXPR, "noexcept_expr", tcc_unary, 1)
 257
 258 /* A placeholder for an expression that is not type-dependent, but
 259    does occur in a template.  When an expression that is not
 260    type-dependent appears in a larger expression, we must compute the
 261    type of that larger expression.  That computation would normally
 262    modify the original expression, which would change the mangling of
 263    that expression if it appeared in a template argument list.  In
 264    that situation, we create a NON_DEPENDENT_EXPR to take the place of
 265    the original expression.  The expression is the only operand -- it
 266    is only needed for diagnostics.  */
 267 DEFTREECODE (NON_DEPENDENT_EXPR, "non_dependent_expr", tcc_expression, 1)
 268
 269 /* CTOR_INITIALIZER is a placeholder in template code for a call to
 270    setup_vtbl_pointer (and appears in all functions, not just ctors).  */
 271 DEFTREECODE (CTOR_INITIALIZER, "ctor_initializer", tcc_expression, 1)
 272
 273 DEFTREECODE (TRY_BLOCK, "try_block", tcc_statement, 2)
 274
 275 DEFTREECODE (EH_SPEC_BLOCK, "eh_spec_block", tcc_statement, 2)
 276
 277 /* A HANDLER wraps a catch handler for the HANDLER_TYPE.  If this is
 278    CATCH_ALL_TYPE, then the handler catches all types.  The declaration of
 279    the catch variable is in HANDLER_PARMS, and the body block in
 280    HANDLER_BODY.  */
 281 DEFTREECODE (HANDLER, "handler", tcc_statement, 2)
 282
 283 /* A MUST_NOT_THROW_EXPR wraps an expression that may not
 284    throw, and must call terminate if it does.  The second argument
 285    is a condition, used in templates to express noexcept (condition).  */
 286 DEFTREECODE (MUST_NOT_THROW_EXPR, "must_not_throw_expr", tcc_expression, 2)
 287
 288 /* A CLEANUP_STMT marks the point at which a declaration is fully
 289    constructed.  The CLEANUP_EXPR is run on behalf of CLEANUP_DECL
 290    when CLEANUP_BODY completes.  */
 291 DEFTREECODE (CLEANUP_STMT, "cleanup_stmt", tcc_statement, 3)
 292
 293 /* Represents an 'if' statement. The operands are IF_COND,
 294    THEN_CLAUSE, and ELSE_CLAUSE, and the current scope, respectively.  */
 295 /* ??? It is currently still necessary to distinguish between IF_STMT
 296    and COND_EXPR for the benefit of templates.  */
 297 DEFTREECODE (IF_STMT, "if_stmt", tcc_statement, 4)
 298
 299 /* Used to represent a `for' statement. The operands are
 300    FOR_INIT_STMT, FOR_COND, FOR_EXPR, and FOR_BODY, respectively.  */
 301 DEFTREECODE (FOR_STMT, "for_stmt", tcc_statement, 5)
 302
 303 /* Used to represent a range-based `for' statement. The operands are
 304    RANGE_FOR_DECL, RANGE_FOR_EXPR, RANGE_FOR_BODY, and RANGE_FOR_SCOPE,
 305    respectively.  Only used in templates.  */
 306 DEFTREECODE (RANGE_FOR_STMT, "range_for_stmt", tcc_statement, 4)
 307
 308 /* Used to represent a 'while' statement. The operands are WHILE_COND
 309    and WHILE_BODY, respectively.  */
 310 DEFTREECODE (WHILE_STMT, "while_stmt", tcc_statement, 2)
 311
 312 /* Used to represent a 'do' statement. The operands are DO_BODY and
 313    DO_COND, respectively.  */
 314 DEFTREECODE (DO_STMT, "do_stmt", tcc_statement, 2)
 315
 316 /* Used to represent a 'break' statement.  */
 317 DEFTREECODE (BREAK_STMT, "break_stmt", tcc_statement, 0)
 318
 319 /* Used to represent a 'continue' statement.  */
 320 DEFTREECODE (CONTINUE_STMT, "continue_stmt", tcc_statement, 0)
 321
 322 /* Used to represent a 'switch' statement. The operands are
 323    SWITCH_STMT_COND, SWITCH_STMT_BODY, SWITCH_STMT_TYPE, and
 324    SWITCH_STMT_SCOPE, respectively.  */
 325 DEFTREECODE (SWITCH_STMT, "switch_stmt", tcc_statement, 4)
 326
 327 /* Used to represent an expression statement.  Use `EXPR_STMT_EXPR' to
 328    obtain the expression.  */
 329 DEFTREECODE (EXPR_STMT, "expr_stmt", tcc_expression, 1)
 330
 331 DEFTREECODE (TAG_DEFN, "tag_defn", tcc_expression, 0)
 332
 333 /* Represents an 'offsetof' expression during template expansion.  */
 334 DEFTREECODE (OFFSETOF_EXPR, "offsetof_expr", tcc_expression, 2)
 335
 336 /* Represents an '__builtin_addressof' expression during template
 337    expansion.  This is similar to ADDR_EXPR, but it doesn't invoke
 338    overloaded & operators.  */
 339 DEFTREECODE (ADDRESSOF_EXPR, "addressof_expr", tcc_expression, 1)
 340
 341 /* Represents the -> operator during template expansion.  */
 342 DEFTREECODE (ARROW_EXPR, "arrow_expr", tcc_expression, 1)
 343
 344 /* Represents an '__alignof__' expression during template
 345    expansion.  */
 346 DEFTREECODE (ALIGNOF_EXPR, "alignof_expr", tcc_expression, 1)
 347
 348 /* Represents an Objective-C++ '@encode' expression during template
 349    expansion.  */
 350 DEFTREECODE (AT_ENCODE_EXPR, "at_encode_expr", tcc_expression, 1)
 351
 352 /* A STMT_EXPR represents a statement-expression during template
 353    expansion.  This is the GCC extension { ( ... ) }.  The
 354    STMT_EXPR_STMT is the statement given by the expression.  */
 355 DEFTREECODE (STMT_EXPR, "stmt_expr", tcc_expression, 1)
 356
 357 /* Unary plus. Operand 0 is the expression to which the unary plus
 358    is applied.  */
 359 DEFTREECODE (UNARY_PLUS_EXPR, "unary_plus_expr", tcc_unary, 1)
 360
 361 /** C++11 extensions. */
 362
 363 /* A static assertion.  This is a C++11 extension.
 364    STATIC_ASSERT_CONDITION contains the condition that is being
 365    checked.  STATIC_ASSERT_MESSAGE contains the message (a string
 366    literal) to be displayed if the condition fails to hold.  */
 367 DEFTREECODE (STATIC_ASSERT, "static_assert", tcc_exceptional, 0)
 368
 369 /* Represents an argument pack of types (or templates). An argument
 370    pack stores zero or more arguments that will be used to instantiate
 371    a parameter pack.
 372
 373    ARGUMENT_PACK_ARGS retrieves the arguments stored in the argument
 374    pack.
 375
 376    Example:
 377      template<typename... Values>
 378      class tuple { ... };
 379
 380      tuple<int, float, double> t;
 381
 382    Values is a (template) parameter pack. When tuple<int, float,
 383    double> is instantiated, the Values parameter pack is instantiated
 384    with the argument pack <int, float, double>. ARGUMENT_PACK_ARGS will
 385    be a TREE_VEC containing int, float, and double.  */
 386 DEFTREECODE (TYPE_ARGUMENT_PACK, "type_argument_pack", tcc_type, 0)
 387
 388 /* Represents an argument pack of values, which can be used either for
 389    non-type template arguments or function call arguments.
 390
 391    NONTYPE_ARGUMENT_PACK plays precisely the same role as
 392    TYPE_ARGUMENT_PACK, but will be used for packing non-type template
 393    arguments (e.g., "int... Dimensions") or function arguments ("const
 394    Args&... args"). */
 395 DEFTREECODE (NONTYPE_ARGUMENT_PACK, "nontype_argument_pack", tcc_expression, 1)
 396
 397 /* Represents a type expression that will be expanded into a list of
 398    types when instantiated with one or more argument packs.
 399
 400    PACK_EXPANSION_PATTERN retrieves the expansion pattern. This is
 401    the type or expression that we will substitute into with each
 402    argument in an argument pack.
 403
 404    SET_PACK_EXPANSION_PATTERN sets the expansion pattern.
 405
 406    PACK_EXPANSION_PARAMETER_PACKS contains a TREE_LIST of the parameter
 407    packs that are used in this pack expansion.
 408
 409    Example:
 410      template<typename... Values>
 411      struct tied : tuple<Values&...> {
 412        // ...
 413      };
 414
 415    The derivation from tuple contains a TYPE_PACK_EXPANSION for the
 416    template arguments. Its PACK_EXPANSION_PATTERN is "Values&" and its
 417    PACK_EXPANSION_PARAMETER_PACKS will contain "Values".  */
 418 DEFTREECODE (TYPE_PACK_EXPANSION, "type_pack_expansion", tcc_type, 0)
 419
 420 /* Represents an expression that will be expanded into a list of
 421    expressions when instantiated with one or more argument packs.
 422
 423    EXPR_PACK_EXPANSION plays precisely the same role as TYPE_PACK_EXPANSION,
 424    but will be used for expressions.  */
 425 DEFTREECODE (EXPR_PACK_EXPANSION, "expr_pack_expansion", tcc_expression, 3)
 426
 427 /* Selects the Ith parameter out of an argument pack. This node will
 428    be used when instantiating pack expansions; see
 429    tsubst_pack_expansion.
 430
 431    ARGUMENT_PACK_SELECT_FROM_PACK contains the *_ARGUMENT_PACK node
 432    from which the argument will be selected.
 433
 434    ARGUMENT_PACK_SELECT_INDEX contains the index into the argument
 435    pack that will be returned by this ARGUMENT_PACK_SELECT node. The
 436    index is a machine integer.  */
 437 DEFTREECODE (ARGUMENT_PACK_SELECT, "argument_pack_select", tcc_exceptional, 0)
 438
 439 /* Fold expressions allow the expansion of a template argument pack
 440    over a binary operator.
 441
 442    FOLD_EXPR_MOD_P is true when the fold operation is a compound assignment
 443    operator.
 444
 445    FOLD_EXPR_OP is an INTEGER_CST storing the tree code for the folded
 446    expression. Note that when FOLDEXPR_MOD_P is true, the operator is
 447    a compound assignment operator for that kind of expression.
 448
 449    FOLD_EXPR_PACK is an expression containing an unexpanded parameter pack;
 450    when expanded, each term becomes an argument of the folded expression.
 451
 452    In a BINARY_FOLD_EXPRESSION, FOLD_EXPR_INIT is the non-pack argument. */
 453 DEFTREECODE (UNARY_LEFT_FOLD_EXPR, "unary_left_fold_expr", tcc_expression, 2)
 454 DEFTREECODE (UNARY_RIGHT_FOLD_EXPR, "unary_right_fold_expr", tcc_expression, 2)
 455 DEFTREECODE (BINARY_LEFT_FOLD_EXPR, "binary_left_fold_expr", tcc_expression, 3)
 456 DEFTREECODE (BINARY_RIGHT_FOLD_EXPR, "binary_right_fold_expr", tcc_expression, 3)
 457
 458
 459 /** C++ extensions. */
 460
 461 /* Represents a trait expression during template expansion.  */
 462 DEFTREECODE (TRAIT_EXPR, "trait_expr", tcc_exceptional, 0)
 463
 464 /* A lambda expression.  This is a C++0x extension.
 465    LAMBDA_EXPR_DEFAULT_CAPTURE_MODE is an enum for the default, which may be
 466    none.
 467    LAMBDA_EXPR_CAPTURE_LIST holds the capture-list, including `this'.
 468    LAMBDA_EXPR_THIS_CAPTURE goes straight to the capture of `this', if it exists.
 469    LAMBDA_EXPR_PENDING_PROXIES is a vector of capture proxies which need to
 470    be pushed once scope returns to the lambda.
 471    LAMBDA_EXPR_MUTABLE_P signals whether this lambda was declared mutable.  */
 472 DEFTREECODE (LAMBDA_EXPR, "lambda_expr", tcc_exceptional, 0)
 473
 474 /* The declared type of an expression.  This is a C++0x extension.
 475    DECLTYPE_TYPE_EXPR is the expression whose type we are computing.
 476    DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P states whether the
 477    expression was parsed as an id-expression or a member access
 478    expression. When false, it was parsed as a full expression.
 479    DECLTYPE_FOR_LAMBDA_CAPTURE is set if we want lambda capture semantics.
 480    DECLTYPE_FOR_LAMBDA_RETURN is set if we want lambda return deduction.  */
 481 DEFTREECODE (DECLTYPE_TYPE, "decltype_type", tcc_type, 0)
 482
 483 /* A type designated by `__underlying_type (type)'.
 484    UNDERLYING_TYPE_TYPE is the type in question.  */
 485 DEFTREECODE (UNDERLYING_TYPE, "underlying_type", tcc_type, 0)
 486
 487 /* A type designated by one of the bases type traits.
 488    BASES_TYPE is the type in question.  */
 489 DEFTREECODE (BASES, "bases", tcc_type, 0)
 490
 491 /* Used to represent the template information stored by template
 492    specializations.
 493    The accessors are:
 494    TI_TEMPLATE the template declaration associated to the specialization
 495    TI_ARGS the arguments of the template specialization
 496    TI_TYPEDEFS_NEEDING_ACCESS_CHECKING the vector of typedefs used in
 497    the pattern of the template for which access check is needed at template
 498    instantiation time.  */
 499 DEFTREECODE (TEMPLATE_INFO, "template_info", tcc_exceptional, 0)
 500
 501 /* Extensions for Concepts. */
 502
 503 /* Used to represent information associated with constrained declarations. */
 504 DEFTREECODE (CONSTRAINT_INFO, "constraint_info", tcc_exceptional, 0)
 505
 506 /* A wildcard declaration is a placeholder for a template parameter
 507    used to resolve constrained-type-names in concepts.  During
 508    resolution, the matching argument is saved as the TREE_TYPE
 509    of the wildcard.  */
 510 DEFTREECODE (WILDCARD_DECL, "wildcard_decl", tcc_declaration, 0)
 511
 512 /* A requires-expr is a binary expression. The first operand is
 513    its parameter list (possibly NULL). The second is a list of
 514    requirements, which are denoted by the _REQ* tree codes
 515    below. */
 516 DEFTREECODE (REQUIRES_EXPR,   "requires_expr", tcc_expression, 2)
 517
 518 /* A requirement for an expression. */
 519 DEFTREECODE (SIMPLE_REQ, "simple_req", tcc_expression, 1)
 520
 521 /* A requirement for a type. */
 522 DEFTREECODE (TYPE_REQ, "type_req", tcc_expression, 1)
 523
 524 /* A requirement for an expression and its properties. The
 525    first operand is the expression, and the 2nd is its type.
 526    The accessor COMPOUND_REQ_NOEXCEPT determines whether
 527    the noexcept keyword was present. */
 528 DEFTREECODE (COMPOUND_REQ, "compound_req", tcc_expression, 2)
 529
 530 /* A requires clause within a requires expression. */
 531 DEFTREECODE (NESTED_REQ, "nested_req", tcc_expression, 1)
 532
 533 /* Constraints are modeled as kinds of expressions.
 534    The operands of a constraint can be either types or expressions.
 535    Unlike expressions, constraints do not have a type. */
 536
 537 /* A predicate constraint evaluates an expression E.
 538
 539    PRED_CONSTR_EXPR has the expression to be evaluated. */
 540 DEFTREECODE (PRED_CONSTR, "pred_constr", tcc_expression, 1)
 541
 542 /* A check constraint represents the checking of a concept
 543    C. It has two operands: the template defining the concept
 544    and a sequence of template arguments.
 545
 546    CHECK_CONSTR_CONCEPT has the concept definition
 547    CHECK_CONSTR_ARGUMENTS are the template arguments */
 548 DEFTREECODE (CHECK_CONSTR, "check_constr", tcc_expression, 2)
 549
 550 /* An expression constraint determines the validity of a expression E.
 551
 552    EXPR_CONST_EXPR has the expression being validated. */
 553 DEFTREECODE (EXPR_CONSTR, "expr_constr", tcc_expression, 1)
 554
 555 /* A type constraint determines the validity of a type T. Note that
 556
 557    TYPE_CONST_TYPE has the type being validated */
 558 DEFTREECODE (TYPE_CONSTR, "type_constr", tcc_expression, 1)
 559
 560 /* An implicit conversion constraint determines if an expression
 561    E is implicitly convertible to a type T. Note that T may
 562    be dependent but does not contain any placeholders.
 563
 564    ICONV_CONSTR_EXPR has the expression E.
 565    ICONV_CONSTR_TYPE has the type T.
 566    */
 567 DEFTREECODE (ICONV_CONSTR, "iconv_constr", tcc_expression, 2)
 568
 569 /* An argument deduction constraint determines if the type of an
 570    expression E can be deduced from a type pattern T. Note that
 571    T must contain at least one place holder.
 572
 573    DEDUCT_CONSTR_EXPR has the expression E
 574    DEDUCT_CONSTR_PATTERN has the type pattern T.
 575    DEDUCT_CONSTR_PLACEHOLDERS has the list of placeholder nodes in T. */
 576 DEFTREECODE (DEDUCT_CONSTR, "deduct_constr", tcc_expression, 3)
 577
 578 /* An exception constraint determines if, for an expression E,
 579    noexcept(E) is true.
 580
 581    EXCEPT_CONSTR_EXPR has the expression E. */
 582 DEFTREECODE (EXCEPT_CONSTR, "except_constr", tcc_expression, 1)
 583
 584 /* A parameterized constraint declares constraint variables, which
 585    are used in expression, type, and exception constraints.
 586
 587    PARM_CONSTR_PARMS has a TREE_LIST of parameter declarations.
 588    PARM_CONSTR_OPERAND has the nested constraint. */
 589 DEFTREECODE (PARM_CONSTR, "parm_constr", tcc_expression, 2)
 590
 591 /* The conjunction and disjunction of two constraints, respectively.
 592    Operands are accessed using TREE_OPERAND. */
 593 DEFTREECODE (CONJ_CONSTR, "conj_constr", tcc_expression, 2)
 594 DEFTREECODE (DISJ_CONSTR, "disj_constr", tcc_expression, 2)
 595
 596
 597 /*
 598 Local variables:
 599 mode:c
 600 End:
 601 */