| /* This file contains the definitions and documentation for the | 
 |    tree codes used in GCC. | 
 |    Copyright (C) 1987, 1988, 1993, 1995, 1997, 1998, 2000, 2001, 2004, 2005,  | 
 |    2006 Free Software Foundation, Inc. | 
 |  | 
 | This file is part of GCC. | 
 |  | 
 | GCC is free software; you can redistribute it and/or modify it under | 
 | the terms of the GNU General Public License as published by the Free | 
 | Software Foundation; either version 2, or (at your option) any later | 
 | version. | 
 |  | 
 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | 
 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | 
 | FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License | 
 | for more details. | 
 |  | 
 | You should have received a copy of the GNU General Public License | 
 | along with GCC; see the file COPYING.  If not, write to the Free | 
 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA | 
 | 02110-1301, USA.  */ | 
 |  | 
 |  | 
 | /* For tcc_references, tcc_expression, tcc_comparison, tcc_unary, | 
 |    tcc_binary, and tcc_statement nodes, which use struct tree_exp, the | 
 |    4th element is the number of argument slots to allocate.  This | 
 |    determines the size of the tree node object.  Other nodes use | 
 |    different structures, and the size is determined by the tree_union | 
 |    member structure; the 4th element should be zero.  Languages that | 
 |    define language-specific tcc_exceptional or tcc_constant codes must | 
 |    define the tree_size langhook to say how big they are. | 
 |  | 
 |    These tree codes have been sorted so that the macros in tree.h that | 
 |    check for various tree codes are optimized into range checks.  This | 
 |    gives a measurable performance improvement.  When adding a new | 
 |    code, consider its placement in relation to the other codes.  */ | 
 |  | 
 | /* Any erroneous construct is parsed into a node of this type. | 
 |    This type of node is accepted without complaint in all contexts | 
 |    by later parsing activities, to avoid multiple error messages | 
 |    for one error. | 
 |    No fields in these nodes are used except the TREE_CODE.  */ | 
 | DEFTREECODE (ERROR_MARK, "error_mark", tcc_exceptional, 0) | 
 |  | 
 | /* Used to represent a name (such as, in the DECL_NAME of a decl node). | 
 |    Internally it looks like a STRING_CST node. | 
 |    There is only one IDENTIFIER_NODE ever made for any particular name. | 
 |    Use `get_identifier' to get it (or create it, the first time).  */ | 
 | DEFTREECODE (IDENTIFIER_NODE, "identifier_node", tcc_exceptional, 0) | 
 |  | 
 | /* Has the TREE_VALUE and TREE_PURPOSE fields.  */ | 
 | /* These nodes are made into lists by chaining through the | 
 |    TREE_CHAIN field.  The elements of the list live in the | 
 |    TREE_VALUE fields, while TREE_PURPOSE fields are occasionally | 
 |    used as well to get the effect of Lisp association lists.  */ | 
 | DEFTREECODE (TREE_LIST, "tree_list", tcc_exceptional, 0) | 
 |  | 
 | /* These nodes contain an array of tree nodes.  */ | 
 | DEFTREECODE (TREE_VEC, "tree_vec", tcc_exceptional, 0) | 
 |  | 
 | /* A symbol binding block.  These are arranged in a tree, | 
 |    where the BLOCK_SUBBLOCKS field contains a chain of subblocks | 
 |    chained through the BLOCK_CHAIN field. | 
 |    BLOCK_SUPERCONTEXT points to the parent block. | 
 |      For a block which represents the outermost scope of a function, it | 
 |      points to the FUNCTION_DECL node. | 
 |    BLOCK_VARS points to a chain of decl nodes. | 
 |    BLOCK_CHAIN points to the next BLOCK at the same level. | 
 |    BLOCK_ABSTRACT_ORIGIN points to the original (abstract) tree node which | 
 |    this block is an instance of, or else is NULL to indicate that this | 
 |    block is not an instance of anything else.  When non-NULL, the value | 
 |    could either point to another BLOCK node or it could point to a | 
 |    FUNCTION_DECL node (e.g. in the case of a block representing the | 
 |    outermost scope of a particular inlining of a function). | 
 |    BLOCK_ABSTRACT is nonzero if the block represents an abstract | 
 |    instance of a block (i.e. one which is nested within an abstract | 
 |    instance of an inline function). | 
 |    TREE_ASM_WRITTEN is nonzero if the block was actually referenced | 
 |    in the generated assembly.  */ | 
 | DEFTREECODE (BLOCK, "block", tcc_exceptional, 0) | 
 |  | 
 | /* Each data type is represented by a tree node whose code is one of | 
 |    the following:  */ | 
 | /* Each node that represents a data type has a component TYPE_SIZE | 
 |    containing a tree that is an expression for the size in bits. | 
 |    The TYPE_MODE contains the machine mode for values of this type. | 
 |    The TYPE_POINTER_TO field contains a type for a pointer to this type, | 
 |      or zero if no such has been created yet. | 
 |    The TYPE_NEXT_VARIANT field is used to chain together types | 
 |      that are variants made by type modifiers such as "const" and "volatile". | 
 |    The TYPE_MAIN_VARIANT field, in any member of such a chain, | 
 |      points to the start of the chain. | 
 |    The TYPE_NONCOPIED_PARTS field is a list specifying which parts | 
 |      of an object of this type should *not* be copied by assignment. | 
 |      The TREE_VALUE of each is a FIELD_DECL that should not be | 
 |      copied.  The TREE_PURPOSE is an initial value for that field when | 
 |      an object of this type is initialized via an INIT_EXPR.  It may | 
 |      be NULL if no special value is required.  Even the things in this | 
 |      list are copied if the right-hand side of an assignment is known | 
 |      to be a complete object (rather than being, perhaps, a subobject | 
 |      of some other object.)  The determination of what constitutes a | 
 |      complete object is done by fixed_type_p. | 
 |    The TYPE_NAME field contains info on the name used in the program | 
 |      for this type (for GDB symbol table output).  It is either a | 
 |      TYPE_DECL node, for types that are typedefs, or an IDENTIFIER_NODE | 
 |      in the case of structs, unions or enums that are known with a tag, | 
 |      or zero for types that have no special name. | 
 |    The TYPE_CONTEXT for any sort of type which could have a name or | 
 |     which could have named members (e.g. tagged types in C/C++) will | 
 |     point to the node which represents the scope of the given type, or | 
 |     will be NULL_TREE if the type has "file scope".  For most types, this | 
 |     will point to a BLOCK node or a FUNCTION_DECL node, but it could also | 
 |     point to a FUNCTION_TYPE node (for types whose scope is limited to the | 
 |     formal parameter list of some function type specification) or it | 
 |     could point to a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE node | 
 |     (for C++ "member" types). | 
 |     For non-tagged-types, TYPE_CONTEXT need not be set to anything in | 
 |     particular, since any type which is of some type category  (e.g. | 
 |     an array type or a function type) which cannot either have a name | 
 |     itself or have named members doesn't really have a "scope" per se. | 
 |   The TREE_CHAIN field is used as a forward-references to names for | 
 |     ENUMERAL_TYPE, RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE nodes; | 
 |     see below.  */ | 
 |  | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  OFFSET_TYPE, ENUMERAL_TYPE, BOOLEAN_TYPE, INTEGER_TYPE, | 
 |    REAL_TYPE, POINTER_TYPE.  */ | 
 |       | 
 | /* An offset is a pointer relative to an object. | 
 |    The TREE_TYPE field is the type of the object at the offset. | 
 |    The TYPE_OFFSET_BASETYPE points to the node for the type of object | 
 |    that the offset is relative to.  */ | 
 | DEFTREECODE (OFFSET_TYPE, "offset_type", tcc_type, 0) | 
 |  | 
 | /* C enums.  The type node looks just like an INTEGER_TYPE node. | 
 |    The symbols for the values of the enum type are defined by | 
 |    CONST_DECL nodes, but the type does not point to them; | 
 |    however, the TYPE_VALUES is a list in which each element's TREE_PURPOSE | 
 |    is a name and the TREE_VALUE is the value (an INTEGER_CST node).  */ | 
 | /* A forward reference `enum foo' when no enum named foo is defined yet | 
 |    has zero (a null pointer) in its TYPE_SIZE.  The tag name is in | 
 |    the TYPE_NAME field.  If the type is later defined, the normal | 
 |    fields are filled in. | 
 |    RECORD_TYPE, UNION_TYPE, and QUAL_UNION_TYPE forward refs are | 
 |    treated similarly.  */ | 
 | DEFTREECODE (ENUMERAL_TYPE, "enumeral_type", tcc_type, 0) | 
 |  | 
 | /* Boolean type (true or false are the only values).  Looks like an | 
 |    INTEGRAL_TYPE.  */ | 
 | DEFTREECODE (BOOLEAN_TYPE, "boolean_type", tcc_type, 0) | 
 |  | 
 | /* Integer types in all languages, including char in C. | 
 |    Also used for sub-ranges of other discrete types. | 
 |    Has components TYPE_MIN_VALUE, TYPE_MAX_VALUE (expressions, inclusive) | 
 |    and TYPE_PRECISION (number of bits used by this type). | 
 |    In the case of a subrange type in Pascal, the TREE_TYPE | 
 |    of this will point at the supertype (another INTEGER_TYPE, | 
 |    or an ENUMERAL_TYPE or BOOLEAN_TYPE). | 
 |    Otherwise, the TREE_TYPE is zero.  */ | 
 | DEFTREECODE (INTEGER_TYPE, "integer_type", tcc_type, 0) | 
 |  | 
 | /* C's float and double.  Different floating types are distinguished | 
 |    by machine mode and by the TYPE_SIZE and the TYPE_PRECISION.  */ | 
 | DEFTREECODE (REAL_TYPE, "real_type", tcc_type, 0) | 
 |  | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  POINTER_TYPE, REFERENCE_TYPE.  Note that this range | 
 |    overlaps the previous range of ordered types.  */ | 
 |       | 
 | /* All pointer-to-x types have code POINTER_TYPE. | 
 |    The TREE_TYPE points to the node for the type pointed to.  */ | 
 | DEFTREECODE (POINTER_TYPE, "pointer_type", tcc_type, 0) | 
 |  | 
 | /* A reference is like a pointer except that it is coerced | 
 |    automatically to the value it points to.  Used in C++.  */ | 
 | DEFTREECODE (REFERENCE_TYPE, "reference_type", tcc_type, 0) | 
 |  | 
 | /* APPLE LOCAL begin radar 5732232 - blocks */ | 
 | /* All pointer-to-block types have code BLOCK_POINTER_TYPE. | 
 |    The TREE_TYPE points to the node for the type pointed to.  */ | 
 | DEFTREECODE (BLOCK_POINTER_TYPE, "block_pointer_type", tcc_type, 0) | 
 | /* APPLE LOCAL end radar 5732232 - blocks */ | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  COMPLEX_TYPE, VECTOR_TYPE, ARRAY_TYPE.  */ | 
 |       | 
 | /* Complex number types.  The TREE_TYPE field is the data type | 
 |    of the real and imaginary parts.  */ | 
 | DEFTREECODE (COMPLEX_TYPE, "complex_type", tcc_type, 0) | 
 |  | 
 | /* Vector types.  The TREE_TYPE field is the data type of the vector | 
 |    elements.  The TYPE_PRECISION field is the number of subparts of | 
 |    the vector.  */ | 
 | DEFTREECODE (VECTOR_TYPE, "vector_type", tcc_type, 0) | 
 |  | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  ARRAY_TYPE, RECORD_TYPE, UNION_TYPE, QUAL_UNION_TYPE. | 
 |    Note that this range overlaps the previous range.  */ | 
 |       | 
 | /* Types of arrays.  Special fields: | 
 |    TREE_TYPE		  Type of an array element. | 
 |    TYPE_DOMAIN		  Type to index by. | 
 | 			    Its range of values specifies the array length. | 
 |  The field TYPE_POINTER_TO (TREE_TYPE (array_type)) is always nonzero | 
 |  and holds the type to coerce a value of that array type to in C. | 
 |  TYPE_STRING_FLAG indicates a string (in contrast to an array of chars) | 
 |  in languages (such as Chill) that make a distinction.  */ | 
 | /* Array types in C or Pascal */ | 
 | DEFTREECODE (ARRAY_TYPE, "array_type", tcc_type, 0) | 
 |  | 
 | /* Struct in C, or record in Pascal.  */ | 
 | /* Special fields: | 
 |    TYPE_FIELDS  chain of FIELD_DECLs for the fields of the struct, | 
 |      and VAR_DECLs, TYPE_DECLs and CONST_DECLs for record-scope variables, | 
 |      types and enumerators. | 
 |    A few may need to be added for Pascal.  */ | 
 | /* See the comment above, before ENUMERAL_TYPE, for how | 
 |    forward references to struct tags are handled in C.  */ | 
 | DEFTREECODE (RECORD_TYPE, "record_type", tcc_type, 0) | 
 |  | 
 | /* Union in C.  Like a struct, except that the offsets of the fields | 
 |    will all be zero.  */ | 
 | /* See the comment above, before ENUMERAL_TYPE, for how | 
 |    forward references to union tags are handled in C.  */ | 
 | DEFTREECODE (UNION_TYPE, "union_type", tcc_type, 0)	/* C union type */ | 
 |  | 
 | /* Similar to UNION_TYPE, except that the expressions in DECL_QUALIFIER | 
 |    in each FIELD_DECL determine what the union contains.  The first | 
 |    field whose DECL_QUALIFIER expression is true is deemed to occupy | 
 |    the union.  */ | 
 | DEFTREECODE (QUAL_UNION_TYPE, "qual_union_type", tcc_type, 0) | 
 |  | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  VOID_TYPE, FUNCTION_TYPE, METHOD_TYPE.  */ | 
 |       | 
 | /* The void type in C */ | 
 | DEFTREECODE (VOID_TYPE, "void_type", tcc_type, 0) | 
 |  | 
 | /* Type of functions.  Special fields: | 
 |    TREE_TYPE		    type of value returned. | 
 |    TYPE_ARG_TYPES      list of types of arguments expected. | 
 | 	this list is made of TREE_LIST nodes. | 
 |    Types of "Procedures" in languages where they are different from functions | 
 |    have code FUNCTION_TYPE also, but then TREE_TYPE is zero or void type.  */ | 
 | DEFTREECODE (FUNCTION_TYPE, "function_type", tcc_type, 0) | 
 |  | 
 | /* METHOD_TYPE is the type of a function which takes an extra first | 
 |    argument for "self", which is not present in the declared argument list. | 
 |    The TREE_TYPE is the return type of the method.  The TYPE_METHOD_BASETYPE | 
 |    is the type of "self".  TYPE_ARG_TYPES is the real argument list, which | 
 |    includes the hidden argument for "self".  */ | 
 | DEFTREECODE (METHOD_TYPE, "method_type", tcc_type, 0) | 
 |  | 
 | /* This is a language-specific kind of type. | 
 |    Its meaning is defined by the language front end. | 
 |    layout_type does not know how to lay this out, | 
 |    so the front-end must do so manually.  */ | 
 | DEFTREECODE (LANG_TYPE, "lang_type", tcc_type, 0) | 
 |  | 
 | /* Expressions */ | 
 |  | 
 | /* First, the constants.  */ | 
 |  | 
 | /* Contents are in TREE_INT_CST_LOW and TREE_INT_CST_HIGH fields, | 
 |    32 bits each, giving us a 64 bit constant capability.  INTEGER_CST | 
 |    nodes can be shared, and therefore should be considered read only. | 
 |    They should be copied, before setting a flag such as | 
 |    TREE_OVERFLOW.  If an INTEGER_CST has TREE_OVERFLOW or | 
 |    TREE_CONSTANT_OVERFLOW already set, it is known to be unique. | 
 |    INTEGER_CST nodes are created for the integral types, for pointer | 
 |    types and for vector and float types in some circumstances.  */ | 
 | DEFTREECODE (INTEGER_CST, "integer_cst", tcc_constant, 0) | 
 |  | 
 | /* Contents are in TREE_REAL_CST field.  */ | 
 | DEFTREECODE (REAL_CST, "real_cst", tcc_constant, 0) | 
 |  | 
 | /* Contents are in TREE_REALPART and TREE_IMAGPART fields, | 
 |    whose contents are other constant nodes.  */ | 
 | DEFTREECODE (COMPLEX_CST, "complex_cst", tcc_constant, 0) | 
 |  | 
 | /* Contents are in TREE_VECTOR_CST_ELTS field.  */ | 
 | DEFTREECODE (VECTOR_CST, "vector_cst", tcc_constant, 0) | 
 |  | 
 | /* Contents are TREE_STRING_LENGTH and the actual contents of the string.  */ | 
 | DEFTREECODE (STRING_CST, "string_cst", tcc_constant, 0) | 
 |  | 
 | /* Declarations.  All references to names are represented as ..._DECL | 
 |    nodes.  The decls in one binding context are chained through the | 
 |    TREE_CHAIN field.  Each DECL has a DECL_NAME field which contains | 
 |    an IDENTIFIER_NODE.  (Some decls, most often labels, may have zero | 
 |    as the DECL_NAME).  DECL_CONTEXT points to the node representing | 
 |    the context in which this declaration has its scope.  For | 
 |    FIELD_DECLs, this is the RECORD_TYPE, UNION_TYPE, or | 
 |    QUAL_UNION_TYPE node that the field is a member of.  For VAR_DECL, | 
 |    PARM_DECL, FUNCTION_DECL, LABEL_DECL, and CONST_DECL nodes, this | 
 |    points to either the FUNCTION_DECL for the containing function, the | 
 |    RECORD_TYPE or UNION_TYPE for the containing type, or NULL_TREE or | 
 |    a TRANSLATION_UNIT_DECL if the given decl has "file scope". | 
 |    DECL_ABSTRACT_ORIGIN, if non-NULL, points to the original (abstract) | 
 |     ..._DECL node of which this decl is an (inlined or template expanded) | 
 |     instance. | 
 |    The TREE_TYPE field holds the data type of the object, when relevant. | 
 |     LABEL_DECLs have no data type.  For TYPE_DECL, the TREE_TYPE field | 
 |     contents are the type whose name is being declared. | 
 |    The DECL_ALIGN, DECL_SIZE, | 
 |     and DECL_MODE fields exist in decl nodes just as in type nodes. | 
 |     They are unused in LABEL_DECL, TYPE_DECL and CONST_DECL nodes. | 
 |  | 
 |    DECL_FIELD_BIT_OFFSET holds an integer number of bits offset for | 
 |    the location.  DECL_VOFFSET holds an expression for a variable | 
 |    offset; it is to be multiplied by DECL_VOFFSET_UNIT (an integer). | 
 |    These fields are relevant only in FIELD_DECLs and PARM_DECLs. | 
 |  | 
 |    DECL_INITIAL holds the value to initialize a variable to, | 
 |    or the value of a constant.  For a function, it holds the body | 
 |    (a node of type BLOCK representing the function's binding contour | 
 |    and whose body contains the function's statements.)  For a LABEL_DECL | 
 |    in C, it is a flag, nonzero if the label's definition has been seen. | 
 |  | 
 |    PARM_DECLs use a special field: | 
 |    DECL_ARG_TYPE is the type in which the argument is actually | 
 |     passed, which may be different from its type within the function. | 
 |  | 
 |    FUNCTION_DECLs use four special fields: | 
 |    DECL_ARGUMENTS holds a chain of PARM_DECL nodes for the arguments. | 
 |    DECL_RESULT holds a RESULT_DECL node for the value of a function. | 
 |     The DECL_RTL field is 0 for a function that returns no value. | 
 |     (C functions returning void have zero here.) | 
 |     The TREE_TYPE field is the type in which the result is actually | 
 |     returned.  This is usually the same as the return type of the | 
 |     FUNCTION_DECL, but it may be a wider integer type because of | 
 |     promotion. | 
 |    DECL_FUNCTION_CODE is a code number that is nonzero for | 
 |     built-in functions.  Its value is an enum built_in_function | 
 |     that says which built-in function it is. | 
 |  | 
 |    DECL_SOURCE_FILE holds a filename string and DECL_SOURCE_LINE | 
 |    holds a line number.  In some cases these can be the location of | 
 |    a reference, if no definition has been seen. | 
 |  | 
 |    DECL_ABSTRACT is nonzero if the decl represents an abstract instance | 
 |    of a decl (i.e. one which is nested within an abstract instance of a | 
 |    inline function.  */ | 
 |  | 
 | DEFTREECODE (FUNCTION_DECL, "function_decl", tcc_declaration, 0) | 
 | DEFTREECODE (LABEL_DECL, "label_decl", tcc_declaration, 0) | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  FIELD_DECL, VAR_DECL, CONST_DECL, PARM_DECL, | 
 |    TYPE_DECL.  */ | 
 | DEFTREECODE (FIELD_DECL, "field_decl", tcc_declaration, 0) | 
 | DEFTREECODE (VAR_DECL, "var_decl", tcc_declaration, 0) | 
 | DEFTREECODE (CONST_DECL, "const_decl", tcc_declaration, 0) | 
 | DEFTREECODE (PARM_DECL, "parm_decl", tcc_declaration, 0) | 
 | DEFTREECODE (TYPE_DECL, "type_decl", tcc_declaration, 0) | 
 | DEFTREECODE (RESULT_DECL, "result_decl", tcc_declaration, 0) | 
 |  | 
 | /* Memory tags used in tree-ssa to represent memory locations in | 
 |    virtual SSA.  */ | 
 | DEFTREECODE (STRUCT_FIELD_TAG, "struct_field_tag", tcc_declaration, 0) | 
 | DEFTREECODE (NAME_MEMORY_TAG, "name_memory_tag", tcc_declaration, 0) | 
 | DEFTREECODE (SYMBOL_MEMORY_TAG, "symbol_memory_tag", tcc_declaration, 0) | 
 |  | 
 | /* A namespace declaration.  Namespaces appear in DECL_CONTEXT of other | 
 |    _DECLs, providing a hierarchy of names.  */ | 
 | DEFTREECODE (NAMESPACE_DECL, "namespace_decl", tcc_declaration, 0) | 
 |  | 
 | /* A translation unit.  This is not technically a declaration, since it | 
 |    can't be looked up, but it's close enough.  */ | 
 | DEFTREECODE (TRANSLATION_UNIT_DECL, "translation_unit_decl",\ | 
 | 	     tcc_declaration, 0) | 
 |  | 
 | /* References to storage.  */ | 
 |  | 
 | /* Value is structure or union component. | 
 |    Operand 0 is the structure or union (an expression). | 
 |    Operand 1 is the field (a node of type FIELD_DECL). | 
 |    Operand 2, if present, is the value of DECL_FIELD_OFFSET, measured | 
 |    in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT.  */ | 
 | DEFTREECODE (COMPONENT_REF, "component_ref", tcc_reference, 3) | 
 |  | 
 | /* Reference to a group of bits within an object.  Similar to COMPONENT_REF | 
 |    except the position is given explicitly rather than via a FIELD_DECL. | 
 |    Operand 0 is the structure or union expression; | 
 |    operand 1 is a tree giving the number of bits being referenced; | 
 |    operand 2 is a tree giving the position of the first referenced bit. | 
 |    The field can be either a signed or unsigned field; | 
 |    BIT_FIELD_REF_UNSIGNED says which.  */ | 
 | DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", tcc_reference, 3) | 
 |  | 
 | /* The ordering of the following codes is optimized for the checking | 
 |    macros in tree.h.  Changing the order will degrade the speed of the | 
 |    compiler.  INDIRECT_REF, ALIGN_INDIRECT_REF, MISALIGNED_INDIRECT_REF.  */ | 
 |  | 
 | /* C unary `*' or Pascal `^'.  One operand, an expression for a pointer.  */ | 
 | DEFTREECODE (INDIRECT_REF, "indirect_ref", tcc_reference, 1) | 
 |  | 
 | /* Like above, but aligns the referenced address (i.e, if the address | 
 |    in P is not aligned on TYPE_ALIGN boundary, then &(*P) != P).  */ | 
 | DEFTREECODE (ALIGN_INDIRECT_REF, "align_indirect_ref", tcc_reference, 1) | 
 |  | 
 | /* Same as INDIRECT_REF, but also specifies the alignment of the referenced | 
 |    address: | 
 |    Operand 0 is the referenced address (a pointer); | 
 |    Operand 1 is an INTEGER_CST which represents the alignment of the address, | 
 |    or 0 if the alignment is unknown.  */ | 
 | DEFTREECODE (MISALIGNED_INDIRECT_REF, "misaligned_indirect_ref", tcc_reference, 2) | 
 |  | 
 | /* Array indexing. | 
 |    Operand 0 is the array; operand 1 is a (single) array index. | 
 |    Operand 2, if present, is a copy of TYPE_MIN_VALUE of the index. | 
 |    Operand 3, if present, is the element size, measured in units of | 
 |    the alignment of the element type.  */ | 
 | DEFTREECODE (ARRAY_REF, "array_ref", tcc_reference, 4) | 
 |  | 
 | /* Likewise, except that the result is a range ("slice") of the array.  The | 
 |    starting index of the resulting array is taken from operand 1 and the size | 
 |    of the range is taken from the type of the expression.  */ | 
 | DEFTREECODE (ARRAY_RANGE_REF, "array_range_ref", tcc_reference, 4) | 
 |  | 
 | /* Used to represent lookup of runtime type dependent data.  Often this is | 
 |    a reference to a vtable, but it needn't be.  Operands are: | 
 |    OBJ_TYPE_REF_EXPR: An expression that evaluates the value to use. | 
 |    OBJ_TYPE_REF_OBJECT: Is the object on whose behalf the lookup is | 
 |    being performed.  Through this the optimizers may be able to statically | 
 |    determine the dynamic type of the object. | 
 |    OBJ_TYPE_REF_TOKEN: Something front-end specific used to resolve the | 
 |    reference to something simpler, usually to the address of a DECL. | 
 |    Never touched by the middle-end.  Good choices would be either an | 
 |    identifier or a vtable index.  */ | 
 | DEFTREECODE (OBJ_TYPE_REF, "obj_type_ref", tcc_expression, 3) | 
 |  | 
 | /* The exception object from the runtime.  */ | 
 | DEFTREECODE (EXC_PTR_EXPR, "exc_ptr_expr", tcc_expression, 0) | 
 |  | 
 | /* The filter object from the runtime.  */ | 
 | DEFTREECODE (FILTER_EXPR, "filter_expr", tcc_expression, 0) | 
 |  | 
 | /* Constructor: return an aggregate value made from specified components. | 
 |    In C, this is used only for structure and array initializers. | 
 |    The operand is a sequence of component values made out of a VEC of | 
 |    struct constructor_elt. | 
 |  | 
 |    For ARRAY_TYPE: | 
 |    The field INDEX of each constructor_elt is the corresponding index. | 
 |    If the index is a RANGE_EXPR, it is a short-hand for many nodes, | 
 |    one for each index in the range.  (If the corresponding field VALUE | 
 |    has side-effects, they are evaluated once for each element.  Wrap the | 
 |    value in a SAVE_EXPR if you want to evaluate side effects only once.) | 
 |  | 
 |    For RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE: | 
 |    The field INDEX of each node is a FIELD_DECL.  */ | 
 | DEFTREECODE (CONSTRUCTOR, "constructor", tcc_exceptional, 0) | 
 |  | 
 | /* The expression types are mostly straightforward, with the fourth argument | 
 |    of DEFTREECODE saying how many operands there are. | 
 |    Unless otherwise specified, the operands are expressions and the | 
 |    types of all the operands and the expression must all be the same.  */ | 
 |  | 
 | /* Contains two expressions to compute, one followed by the other. | 
 |    the first value is ignored.  The second one's value is used.  The | 
 |    type of the first expression need not agree with the other types.  */ | 
 | DEFTREECODE (COMPOUND_EXPR, "compound_expr", tcc_expression, 2) | 
 |  | 
 | /* Assignment expression.  Operand 0 is the what to set; 1, the new value.  */ | 
 | DEFTREECODE (MODIFY_EXPR, "modify_expr", tcc_expression, 2) | 
 |  | 
 | /* Initialization expression.  Operand 0 is the variable to initialize; | 
 |    Operand 1 is the initializer.  This differs from MODIFY_EXPR in that any | 
 |    reference to the referent of operand 0 within operand 1 is undefined.  */ | 
 | DEFTREECODE (INIT_EXPR, "init_expr", tcc_expression, 2) | 
 |  | 
 | /* For TARGET_EXPR, operand 0 is the target of an initialization, | 
 |    operand 1 is the initializer for the target, which may be void | 
 |      if simply expanding it initializes the target. | 
 |    operand 2 is the cleanup for this node, if any. | 
 |    operand 3 is the saved initializer after this node has been | 
 |    expanded once; this is so we can re-expand the tree later.  */ | 
 | DEFTREECODE (TARGET_EXPR, "target_expr", tcc_expression, 4) | 
 |  | 
 | /* Conditional expression ( ... ? ... : ...  in C). | 
 |    Operand 0 is the condition. | 
 |    Operand 1 is the then-value. | 
 |    Operand 2 is the else-value. | 
 |    Operand 0 may be of any type. | 
 |    Operand 1 must have the same type as the entire expression, unless | 
 |    it unconditionally throws an exception, in which case it should | 
 |    have VOID_TYPE.  The same constraints apply to operand 2.  */ | 
 | DEFTREECODE (COND_EXPR, "cond_expr", tcc_expression, 3) | 
 |  | 
 | /* Vector conditional expression. It is like COND_EXPR, but with | 
 |    vector operands. | 
 |  | 
 |    A = VEC_COND_EXPR ( X < Y, B, C) | 
 |  | 
 |    means | 
 |  | 
 |    for (i=0; i<N; i++) | 
 |      A[i] = X[i] < Y[i] ? B[i] : C[i]; | 
 | */ | 
 | DEFTREECODE (VEC_COND_EXPR, "vec_cond_expr", tcc_expression, 3) | 
 |  | 
 | /* Declare local variables, including making RTL and allocating space. | 
 |    BIND_EXPR_VARS is a chain of VAR_DECL nodes for the variables. | 
 |    BIND_EXPR_BODY is the body, the expression to be computed using | 
 |    the variables.  The value of operand 1 becomes that of the BIND_EXPR. | 
 |    BIND_EXPR_BLOCK is the BLOCK that corresponds to these bindings | 
 |    for debugging purposes.  If this BIND_EXPR is actually expanded, | 
 |    that sets the TREE_USED flag in the BLOCK. | 
 |  | 
 |    The BIND_EXPR is not responsible for informing parsers | 
 |    about these variables.  If the body is coming from the input file, | 
 |    then the code that creates the BIND_EXPR is also responsible for | 
 |    informing the parser of the variables. | 
 |  | 
 |    If the BIND_EXPR is ever expanded, its TREE_USED flag is set. | 
 |    This tells the code for debugging symbol tables not to ignore the BIND_EXPR. | 
 |    If the BIND_EXPR should be output for debugging but will not be expanded, | 
 |    set the TREE_USED flag by hand. | 
 |  | 
 |    In order for the BIND_EXPR to be known at all, the code that creates it | 
 |    must also install it as a subblock in the tree of BLOCK | 
 |    nodes for the function.  */ | 
 | DEFTREECODE (BIND_EXPR, "bind_expr", tcc_expression, 3) | 
 |  | 
 | /* Function call.  Operand 0 is the function. | 
 |    Operand 1 is the argument list, a list of expressions | 
 |    made out of a chain of TREE_LIST nodes. | 
 |    Operand 2 is the static chain argument, or NULL.  */ | 
 | DEFTREECODE (CALL_EXPR, "call_expr", tcc_expression, 3) | 
 |  | 
 | /* Specify a value to compute along with its corresponding cleanup. | 
 |    Operand 0 is the cleanup expression. | 
 |    The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, | 
 |    which must exist.  This differs from TRY_CATCH_EXPR in that operand 1 | 
 |    is always evaluated when cleanups are run.  */ | 
 | DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", tcc_expression, 1) | 
 |  | 
 | /* Specify a cleanup point. | 
 |    Operand 0 is an expression that may have cleanups.  If it does, those | 
 |    cleanups are executed after the expression is expanded. | 
 |  | 
 |    Note that if the expression is a reference to storage, it is forced out | 
 |    of memory before the cleanups are run.  This is necessary to handle | 
 |    cases where the cleanups modify the storage referenced; in the | 
 |    expression 't.i', if 't' is a struct with an integer member 'i' and a | 
 |    cleanup which modifies 'i', the value of the expression depends on | 
 |    whether the cleanup is run before or after 't.i' is evaluated.  When | 
 |    expand_expr is run on 't.i', it returns a MEM.  This is not good enough; | 
 |    the value of 't.i' must be forced out of memory. | 
 |  | 
 |    As a consequence, the operand of a CLEANUP_POINT_EXPR must not have | 
 |    BLKmode, because it will not be forced out of memory.  */ | 
 | DEFTREECODE (CLEANUP_POINT_EXPR, "cleanup_point_expr", tcc_expression, 1) | 
 |  | 
 | /* The following two codes are used in languages that have types where | 
 |    some field in an object of the type contains a value that is used in | 
 |    the computation of another field's offset or size and/or the size of | 
 |    the type.  The positions and/or sizes of fields can vary from object | 
 |    to object of the same type or even for one and the same object within | 
 |    its scope. | 
 |  | 
 |    Record types with discriminants in Ada or schema types in Pascal are | 
 |    examples of such types.  This mechanism is also used to create "fat | 
 |    pointers" for unconstrained array types in Ada; the fat pointer is a | 
 |    structure one of whose fields is a pointer to the actual array type | 
 |    and the other field is a pointer to a template, which is a structure | 
 |    containing the bounds of the array.  The bounds in the type pointed | 
 |    to by the first field in the fat pointer refer to the values in the | 
 |    template. | 
 |  | 
 |    When you wish to construct such a type you need "self-references" | 
 |    that allow you to reference the object having this type from the | 
 |    TYPE node, i.e. without having a variable instantiating this type. | 
 |  | 
 |    Such a "self-references" is done using a PLACEHOLDER_EXPR.  This is | 
 |    a node that will later be replaced with the object being referenced. | 
 |    Its type is that of the object and selects which object to use from | 
 |    a chain of references (see below).  No other slots are used in the | 
 |    PLACEHOLDER_EXPR. | 
 |  | 
 |    For example, if your type FOO is a RECORD_TYPE with a field BAR, | 
 |    and you need the value of <variable>.BAR to calculate TYPE_SIZE | 
 |    (FOO), just substitute <variable> above with a PLACEHOLDER_EXPR | 
 |    whose TREE_TYPE is FOO.  Then construct your COMPONENT_REF with | 
 |    the PLACEHOLDER_EXPR as the first operand (which has the correct | 
 |    type).  Later, when the size is needed in the program, the back-end | 
 |    will find this PLACEHOLDER_EXPR and generate code to calculate the | 
 |    actual size at run-time.  In the following, we describe how this | 
 |    calculation is done. | 
 |  | 
 |    When we wish to evaluate a size or offset, we check whether it contains a | 
 |    PLACEHOLDER_EXPR.  If it does, we call substitute_placeholder_in_expr | 
 |    passing both that tree and an expression within which the object may be | 
 |    found.  The latter expression is the object itself in the simple case of | 
 |    an Ada record with discriminant, but it can be the array in the case of an | 
 |    unconstrained array. | 
 |  | 
 |    In the latter case, we need the fat pointer, because the bounds of | 
 |    the array can only be accessed from it.  However, we rely here on the | 
 |    fact that the expression for the array contains the dereference of | 
 |    the fat pointer that obtained the array pointer.  */ | 
 |  | 
 | /* Denotes a record to later be substituted before evaluating this expression. | 
 |    The type of this expression is used to find the record to replace it.  */ | 
 | DEFTREECODE (PLACEHOLDER_EXPR, "placeholder_expr", tcc_exceptional, 0) | 
 |  | 
 | /* Simple arithmetic.  */ | 
 | DEFTREECODE (PLUS_EXPR, "plus_expr", tcc_binary, 2) | 
 | DEFTREECODE (MINUS_EXPR, "minus_expr", tcc_binary, 2) | 
 | DEFTREECODE (MULT_EXPR, "mult_expr", tcc_binary, 2) | 
 |  | 
 | /* Division for integer result that rounds the quotient toward zero.  */ | 
 | DEFTREECODE (TRUNC_DIV_EXPR, "trunc_div_expr", tcc_binary, 2) | 
 |  | 
 | /* Division for integer result that rounds the quotient toward infinity.  */ | 
 | DEFTREECODE (CEIL_DIV_EXPR, "ceil_div_expr", tcc_binary, 2) | 
 |  | 
 | /* Division for integer result that rounds toward minus infinity.  */ | 
 | DEFTREECODE (FLOOR_DIV_EXPR, "floor_div_expr", tcc_binary, 2) | 
 |  | 
 | /* Division for integer result that rounds toward nearest integer.  */ | 
 | DEFTREECODE (ROUND_DIV_EXPR, "round_div_expr", tcc_binary, 2) | 
 |  | 
 | /* Four kinds of remainder that go with the four kinds of division.  */ | 
 | DEFTREECODE (TRUNC_MOD_EXPR, "trunc_mod_expr", tcc_binary, 2) | 
 | DEFTREECODE (CEIL_MOD_EXPR, "ceil_mod_expr", tcc_binary, 2) | 
 | DEFTREECODE (FLOOR_MOD_EXPR, "floor_mod_expr", tcc_binary, 2) | 
 | DEFTREECODE (ROUND_MOD_EXPR, "round_mod_expr", tcc_binary, 2) | 
 |  | 
 | /* Division for real result.  */ | 
 | DEFTREECODE (RDIV_EXPR, "rdiv_expr", tcc_binary, 2) | 
 |  | 
 | /* Division which is not supposed to need rounding. | 
 |    Used for pointer subtraction in C.  */ | 
 | DEFTREECODE (EXACT_DIV_EXPR, "exact_div_expr", tcc_binary, 2) | 
 |  | 
 | /* Conversion of real to fixed point: four ways to round, | 
 |    like the four ways to divide. | 
 |    CONVERT_EXPR can also be used to convert a real to an integer, | 
 |    and that is what is used in languages that do not have ways of | 
 |    specifying which of these is wanted.  Maybe these are not needed.  */ | 
 | DEFTREECODE (FIX_TRUNC_EXPR, "fix_trunc_expr", tcc_unary, 1) | 
 | DEFTREECODE (FIX_CEIL_EXPR, "fix_ceil_expr", tcc_unary, 1) | 
 | DEFTREECODE (FIX_FLOOR_EXPR, "fix_floor_expr", tcc_unary, 1) | 
 | DEFTREECODE (FIX_ROUND_EXPR, "fix_round_expr", tcc_unary, 1) | 
 |  | 
 | /* Conversion of an integer to a real.  */ | 
 | DEFTREECODE (FLOAT_EXPR, "float_expr", tcc_unary, 1) | 
 |  | 
 | /* Unary negation.  */ | 
 | DEFTREECODE (NEGATE_EXPR, "negate_expr", tcc_unary, 1) | 
 |  | 
 | /* Minimum and maximum values.  When used with floating point, if both | 
 |    operands are zeros, or if either operand is NaN, then it is unspecified | 
 |    which of the two operands is returned as the result.  */ | 
 | DEFTREECODE (MIN_EXPR, "min_expr", tcc_binary, 2) | 
 | DEFTREECODE (MAX_EXPR, "max_expr", tcc_binary, 2) | 
 |  | 
 | /* Represents the absolute value of the operand. | 
 |  | 
 |    An ABS_EXPR must have either an INTEGER_TYPE or a REAL_TYPE.  The | 
 |    operand of the ABS_EXPR must have the same type.  */ | 
 | DEFTREECODE (ABS_EXPR, "abs_expr", tcc_unary, 1) | 
 |  | 
 | /* Shift operations for shift and rotate. | 
 |    Shift means logical shift if done on an | 
 |    unsigned type, arithmetic shift if done on a signed type. | 
 |    The second operand is the number of bits to | 
 |    shift by; it need not be the same type as the first operand and result. | 
 |    Note that the result is undefined if the second operand is larger | 
 |    than or equal to the first operand's type size.  */ | 
 | DEFTREECODE (LSHIFT_EXPR, "lshift_expr", tcc_binary, 2) | 
 | DEFTREECODE (RSHIFT_EXPR, "rshift_expr", tcc_binary, 2) | 
 | DEFTREECODE (LROTATE_EXPR, "lrotate_expr", tcc_binary, 2) | 
 | DEFTREECODE (RROTATE_EXPR, "rrotate_expr", tcc_binary, 2) | 
 |  | 
 | /* Bitwise operations.  Operands have same mode as result.  */ | 
 | DEFTREECODE (BIT_IOR_EXPR, "bit_ior_expr", tcc_binary, 2) | 
 | DEFTREECODE (BIT_XOR_EXPR, "bit_xor_expr", tcc_binary, 2) | 
 | DEFTREECODE (BIT_AND_EXPR, "bit_and_expr", tcc_binary, 2) | 
 | DEFTREECODE (BIT_NOT_EXPR, "bit_not_expr", tcc_unary, 1) | 
 |  | 
 | /* ANDIF and ORIF allow the second operand not to be computed if the | 
 |    value of the expression is determined from the first operand.  AND, | 
 |    OR, and XOR always compute the second operand whether its value is | 
 |    needed or not (for side effects).  The operand may have | 
 |    BOOLEAN_TYPE or INTEGER_TYPE.  In either case, the argument will be | 
 |    either zero or one.  For example, a TRUTH_NOT_EXPR will never have | 
 |    an INTEGER_TYPE VAR_DECL as its argument; instead, a NE_EXPR will be | 
 |    used to compare the VAR_DECL to zero, thereby obtaining a node with | 
 |    value zero or one.  */ | 
 | DEFTREECODE (TRUTH_ANDIF_EXPR, "truth_andif_expr", tcc_expression, 2) | 
 | DEFTREECODE (TRUTH_ORIF_EXPR, "truth_orif_expr", tcc_expression, 2) | 
 | DEFTREECODE (TRUTH_AND_EXPR, "truth_and_expr", tcc_expression, 2) | 
 | DEFTREECODE (TRUTH_OR_EXPR, "truth_or_expr", tcc_expression, 2) | 
 | DEFTREECODE (TRUTH_XOR_EXPR, "truth_xor_expr", tcc_expression, 2) | 
 | DEFTREECODE (TRUTH_NOT_EXPR, "truth_not_expr", tcc_expression, 1) | 
 |  | 
 | /* Relational operators. | 
 |    `EQ_EXPR' and `NE_EXPR' are allowed for any types. | 
 |    The others are allowed only for integer (or pointer or enumeral) | 
 |    or real types. | 
 |    In all cases the operands will have the same type, | 
 |    and the value is always the type used by the language for booleans.  */ | 
 | DEFTREECODE (LT_EXPR, "lt_expr", tcc_comparison, 2) | 
 | DEFTREECODE (LE_EXPR, "le_expr", tcc_comparison, 2) | 
 | DEFTREECODE (GT_EXPR, "gt_expr", tcc_comparison, 2) | 
 | DEFTREECODE (GE_EXPR, "ge_expr", tcc_comparison, 2) | 
 | DEFTREECODE (EQ_EXPR, "eq_expr", tcc_comparison, 2) | 
 | DEFTREECODE (NE_EXPR, "ne_expr", tcc_comparison, 2) | 
 |  | 
 | /* Additional relational operators for floating point unordered.  */ | 
 | DEFTREECODE (UNORDERED_EXPR, "unordered_expr", tcc_comparison, 2) | 
 | DEFTREECODE (ORDERED_EXPR, "ordered_expr", tcc_comparison, 2) | 
 |  | 
 | /* These are equivalent to unordered or ...  */ | 
 | DEFTREECODE (UNLT_EXPR, "unlt_expr", tcc_comparison, 2) | 
 | DEFTREECODE (UNLE_EXPR, "unle_expr", tcc_comparison, 2) | 
 | DEFTREECODE (UNGT_EXPR, "ungt_expr", tcc_comparison, 2) | 
 | DEFTREECODE (UNGE_EXPR, "unge_expr", tcc_comparison, 2) | 
 | DEFTREECODE (UNEQ_EXPR, "uneq_expr", tcc_comparison, 2) | 
 |  | 
 | /* This is the reverse of uneq_expr.  */ | 
 | DEFTREECODE (LTGT_EXPR, "ltgt_expr", tcc_comparison, 2) | 
 |  | 
 | DEFTREECODE (RANGE_EXPR, "range_expr", tcc_binary, 2) | 
 |  | 
 | /* Represents a conversion of type of a value. | 
 |    All conversions, including implicit ones, must be | 
 |    represented by CONVERT_EXPR or NOP_EXPR nodes.  */ | 
 | DEFTREECODE (CONVERT_EXPR, "convert_expr", tcc_unary, 1) | 
 |  | 
 | /* Represents a conversion expected to require no code to be generated.  */ | 
 | DEFTREECODE (NOP_EXPR, "nop_expr", tcc_unary, 1) | 
 |  | 
 | /* Value is same as argument, but guaranteed not an lvalue.  */ | 
 | DEFTREECODE (NON_LVALUE_EXPR, "non_lvalue_expr", tcc_unary, 1) | 
 |  | 
 | /* Represents viewing something of one type as being of a second type. | 
 |    This corresponds to an "Unchecked Conversion" in Ada and roughly to | 
 |    the idiom *(type2 *)&X in C.  The only operand is the value to be | 
 |    viewed as being of another type.  It is undefined if the type of the | 
 |    input and of the expression have different sizes. | 
 |  | 
 |    This code may also be used within the LHS of a MODIFY_EXPR, in which | 
 |    case no actual data motion may occur.  TREE_ADDRESSABLE will be set in | 
 |    this case and GCC must abort if it could not do the operation without | 
 |    generating insns.  */ | 
 | DEFTREECODE (VIEW_CONVERT_EXPR, "view_convert_expr", tcc_reference, 1) | 
 |  | 
 | /* Represents something we computed once and will use multiple times. | 
 |    First operand is that expression.  After it is evaluated once, it | 
 |    will be replaced by the temporary variable that holds the value.  */ | 
 | DEFTREECODE (SAVE_EXPR, "save_expr", tcc_expression, 1) | 
 |  | 
 | /* & in C.  Value is the address at which the operand's value resides. | 
 |    Operand may have any mode.  Result mode is Pmode.  */ | 
 | DEFTREECODE (ADDR_EXPR, "addr_expr", tcc_expression, 1) | 
 |  | 
 | /* Operand0 is a function constant; result is part N of a function | 
 |    descriptor of type ptr_mode.  */ | 
 | DEFTREECODE (FDESC_EXPR, "fdesc_expr", tcc_expression, 2) | 
 |  | 
 | /* Given two real or integer operands of the same type, | 
 |    returns a complex value of the corresponding complex type.  */ | 
 | DEFTREECODE (COMPLEX_EXPR, "complex_expr", tcc_binary, 2) | 
 |  | 
 | /* Complex conjugate of operand.  Used only on complex types.  */ | 
 | DEFTREECODE (CONJ_EXPR, "conj_expr", tcc_unary, 1) | 
 |  | 
 | /* Used only on an operand of complex type, these return | 
 |    a value of the corresponding component type.  */ | 
 | DEFTREECODE (REALPART_EXPR, "realpart_expr", tcc_reference, 1) | 
 | DEFTREECODE (IMAGPART_EXPR, "imagpart_expr", tcc_reference, 1) | 
 |  | 
 | /* Nodes for ++ and -- in C. | 
 |    The second arg is how much to increment or decrement by. | 
 |    For a pointer, it would be the size of the object pointed to.  */ | 
 | DEFTREECODE (PREDECREMENT_EXPR, "predecrement_expr", tcc_expression, 2) | 
 | DEFTREECODE (PREINCREMENT_EXPR, "preincrement_expr", tcc_expression, 2) | 
 | DEFTREECODE (POSTDECREMENT_EXPR, "postdecrement_expr", tcc_expression, 2) | 
 | DEFTREECODE (POSTINCREMENT_EXPR, "postincrement_expr", tcc_expression, 2) | 
 |  | 
 | /* Used to implement `va_arg'.  */ | 
 | DEFTREECODE (VA_ARG_EXPR, "va_arg_expr", tcc_expression, 1) | 
 |  | 
 | /* Evaluate operand 1.  If and only if an exception is thrown during | 
 |    the evaluation of operand 1, evaluate operand 2. | 
 |  | 
 |    This differs from TRY_FINALLY_EXPR in that operand 2 is not evaluated | 
 |    on a normal or jump exit, only on an exception.  */ | 
 | DEFTREECODE (TRY_CATCH_EXPR, "try_catch_expr", tcc_statement, 2) | 
 |  | 
 | /* Evaluate the first operand. | 
 |    The second operand is a cleanup expression which is evaluated | 
 |    on any exit (normal, exception, or jump out) from this expression.  */ | 
 | DEFTREECODE (TRY_FINALLY_EXPR, "try_finally", tcc_statement, 2) | 
 |  | 
 | /* These types of expressions have no useful value, | 
 |    and always have side effects.  */ | 
 |  | 
 | /* Used to represent a local declaration. The operand is DECL_EXPR_DECL.  */ | 
 | DEFTREECODE (DECL_EXPR, "decl_expr", tcc_statement, 1) | 
 |  | 
 | /* A label definition, encapsulated as a statement. | 
 |    Operand 0 is the LABEL_DECL node for the label that appears here. | 
 |    The type should be void and the value should be ignored.  */ | 
 | DEFTREECODE (LABEL_EXPR, "label_expr", tcc_statement, 1) | 
 |  | 
 | /* GOTO.  Operand 0 is a LABEL_DECL node or an expression. | 
 |    The type should be void and the value should be ignored.  */ | 
 | DEFTREECODE (GOTO_EXPR, "goto_expr", tcc_statement, 1) | 
 |  | 
 | /* RETURN.  Evaluates operand 0, then returns from the current function. | 
 |    Presumably that operand is an assignment that stores into the | 
 |    RESULT_DECL that hold the value to be returned. | 
 |    The operand may be null. | 
 |    The type should be void and the value should be ignored.  */ | 
 | DEFTREECODE (RETURN_EXPR, "return_expr", tcc_statement, 1) | 
 |  | 
 | /* Exit the inner most loop conditionally.  Operand 0 is the condition. | 
 |    The type should be void and the value should be ignored.  */ | 
 | DEFTREECODE (EXIT_EXPR, "exit_expr", tcc_statement, 1) | 
 |  | 
 | /* A loop.  Operand 0 is the body of the loop. | 
 |    It must contain an EXIT_EXPR or is an infinite loop. | 
 |    The type should be void and the value should be ignored.  */ | 
 | DEFTREECODE (LOOP_EXPR, "loop_expr", tcc_statement, 1) | 
 |  | 
 | /* Switch expression. | 
 |  | 
 |    TREE_TYPE is the original type of the condition, before any | 
 |    language required type conversions.  It may be NULL, in which case | 
 |    the original type and final types are assumed to be the same. | 
 |  | 
 |    Operand 0 is the expression used to perform the branch, | 
 |    Operand 1 is the body of the switch, which probably contains | 
 |      CASE_LABEL_EXPRs.  It may also be NULL, in which case operand 2 | 
 |      must not be NULL. | 
 |    Operand 2 is either NULL_TREE or a TREE_VEC of the CASE_LABEL_EXPRs | 
 |      of all the cases.  */ | 
 | DEFTREECODE (SWITCH_EXPR, "switch_expr", tcc_statement, 3) | 
 |  | 
 | /* Used to represent a case label. The operands are CASE_LOW and | 
 |    CASE_HIGH, respectively. If CASE_LOW is NULL_TREE, the label is a | 
 |    'default' label. If CASE_HIGH is NULL_TREE, the label is a normal case | 
 |    label.  CASE_LABEL is the corresponding LABEL_DECL.  */ | 
 | DEFTREECODE (CASE_LABEL_EXPR, "case_label_expr", tcc_statement, 3) | 
 |  | 
 | /* RESX.  Resume execution after an exception.  Operand 0 is a | 
 |    number indicating the exception region that is being left.  */ | 
 | DEFTREECODE (RESX_EXPR, "resx_expr", tcc_statement, 1) | 
 |  | 
 | /* Used to represent an inline assembly statement.  ASM_STRING returns a | 
 |    STRING_CST for the instruction (e.g., "mov x, y"). ASM_OUTPUTS, | 
 |    ASM_INPUTS, and ASM_CLOBBERS represent the outputs, inputs, and clobbers | 
 |    for the statement.  */ | 
 | /* APPLE LOCAL begin CW asm blocks */ | 
 | /* One additional field ASM_USES for uses. */ | 
 | DEFTREECODE (ASM_EXPR, "asm_expr", tcc_statement, 5) | 
 | /* APPLE LOCAL end CW asm blocks */ | 
 |  | 
 | /* Variable references for SSA analysis.  New SSA names are created every | 
 |    time a variable is assigned a new value.  The SSA builder uses SSA_NAME | 
 |    nodes to implement SSA versioning.  */ | 
 | DEFTREECODE (SSA_NAME, "ssa_name", tcc_exceptional, 0) | 
 |  | 
 | /* SSA PHI operator.  PHI_RESULT is the new SSA_NAME node created by | 
 |    the PHI node.  PHI_ARG_LENGTH is the number of arguments. | 
 |    PHI_ARG_ELT returns the Ith tuple <ssa_name, edge> from the | 
 |    argument list.  Each tuple contains the incoming reaching | 
 |    definition (SSA_NAME node) and the edge via which that definition | 
 |    is coming through.  */ | 
 | DEFTREECODE (PHI_NODE, "phi_node", tcc_exceptional, 0) | 
 |  | 
 | /* Used to represent a typed exception handler.  CATCH_TYPES is the type (or | 
 |    list of types) handled, and CATCH_BODY is the code for the handler.  */ | 
 | DEFTREECODE (CATCH_EXPR, "catch_expr", tcc_statement, 2) | 
 |  | 
 | /* Used to represent an exception specification.  EH_FILTER_TYPES is a list | 
 |    of allowed types, and EH_FILTER_FAILURE is an expression to evaluate on | 
 |    failure.  EH_FILTER_MUST_NOT_THROW controls which range type to use when | 
 |    expanding.  */ | 
 | DEFTREECODE (EH_FILTER_EXPR, "eh_filter_expr", tcc_statement, 2) | 
 |  | 
 | /* Node used for describing a property that is known at compile | 
 |    time.  */ | 
 | DEFTREECODE (SCEV_KNOWN, "scev_known", tcc_expression, 0) | 
 |  | 
 | /* Node used for describing a property that is not known at compile | 
 |    time.  */ | 
 | DEFTREECODE (SCEV_NOT_KNOWN, "scev_not_known", tcc_expression, 0) | 
 |  | 
 | /* Polynomial chains of recurrences. | 
 |    Under the form: cr = {CHREC_LEFT (cr), +, CHREC_RIGHT (cr)}.  */ | 
 | DEFTREECODE (POLYNOMIAL_CHREC, "polynomial_chrec", tcc_expression, 3) | 
 |  | 
 | /* Used to chain children of container statements together. | 
 |    Use the interface in tree-iterator.h to access this node.  */ | 
 | DEFTREECODE (STATEMENT_LIST, "statement_list", tcc_exceptional, 0) | 
 |  | 
 | /* APPLE LOCAL begin AV vmul_uch --haifa  */ | 
 | /* Used during vectorization to represent computation idioms.  */ | 
 | DEFTREECODE (MULT_UCH_EXPR, "mult_uch", '2', 2) | 
 | /* APPLE LOCAL end AV vmul_uch --haifa  */ | 
 |  | 
 | /* Value handles.  Artificial nodes to represent expressions in | 
 |    partial redundancy elimination (tree-ssa-pre.c).  These nodes are | 
 |    used for expression canonicalization.  If two expressions compute | 
 |    the same value, they will be assigned the same value handle.  */ | 
 | DEFTREECODE (VALUE_HANDLE, "value_handle", tcc_exceptional, 0) | 
 |  | 
 | /* Predicate assertion.  Artificial expression generated by the optimizers | 
 |    to keep track of predicate values.  This expression may only appear on | 
 |    the RHS of assignments. | 
 |     | 
 |    Given X = ASSERT_EXPR <Y, EXPR>, the optimizers can infer | 
 |    two things: | 
 |  | 
 |    	1- X is a copy of Y. | 
 | 	2- EXPR is a GIMPLE conditional expression (as defined by | 
 | 	   is_gimple_condexpr) and is known to be true. | 
 |  | 
 |    The type of the expression is the same as Y.  */ | 
 | DEFTREECODE (ASSERT_EXPR, "assert_expr", tcc_expression, 2) | 
 |  | 
 | /* Base class information. Holds information about a class as a | 
 |    baseclass of itself or another class.  */ | 
 | DEFTREECODE (TREE_BINFO, "tree_binfo", tcc_exceptional, 0) | 
 |  | 
 | /* Records the size for an expression of variable size type.  This is | 
 |    for use in contexts in which we are accessing the entire object, | 
 |    such as for a function call, or block copy. | 
 |    Operand 0 is the real expression. | 
 |    Operand 1 is the size of the type in the expression.  */ | 
 | DEFTREECODE (WITH_SIZE_EXPR, "with_size_expr", tcc_expression, 2) | 
 |  | 
 | /* Extract elements from two input vectors Operand 0 and Operand 1 | 
 |    size VS, according to the offset OFF defined by Operand 2 as | 
 |    follows: | 
 |    If OFF > 0, the last VS - OFF elements of vector OP0 are concatenated to | 
 |    the first OFF elements of the vector OP1. | 
 |    If OFF == 0, then the returned vector is OP1. | 
 |    On different targets OFF may take different forms; It can be an address, in  | 
 |    which case its low log2(VS)-1 bits define the offset, or it can be a mask  | 
 |    generated by the builtin targetm.vectorize.mask_for_load_builtin_decl.  */ | 
 | DEFTREECODE (REALIGN_LOAD_EXPR, "realign_load", tcc_expression, 3) | 
 |  | 
 | /* Low-level memory addressing.  Operands are SYMBOL (static or global | 
 |    variable), BASE (register), INDEX (register), STEP (integer constant), | 
 |    OFFSET (integer constant).  Corresponding address is | 
 |    SYMBOL + BASE + STEP * INDEX + OFFSET.  Only variations and values valid on | 
 |    the target are allowed. | 
 |  | 
 |    The type of STEP, INDEX and OFFSET is sizetype.  The type of BASE is | 
 |    sizetype or a pointer type (if SYMBOL is NULL). | 
 |     | 
 |    The sixth argument is the reference to the original memory access, which | 
 |    is preserved for the purposes of the RTL alias analysis.  The seventh | 
 |    argument is a tag representing results of the tree level alias analysis.  */ | 
 |  | 
 | DEFTREECODE (TARGET_MEM_REF, "target_mem_ref", tcc_reference, 7) | 
 |  | 
 | /* The ordering of the codes between OMP_PARALLEL and OMP_CRITICAL is | 
 |    exposed to TREE_RANGE_CHECK.  */ | 
 | /* OpenMP - #pragma omp parallel [clause1 ... clauseN] | 
 |    Operand 0: OMP_PARALLEL_BODY: Code to be executed by all threads. | 
 |    Operand 1: OMP_PARALLEL_CLAUSES: List of clauses. | 
 |    Operand 2: OMP_PARALLEL_FN: FUNCTION_DECL used when outlining the | 
 | 	      body of the parallel region.  Only valid after | 
 | 	      pass_lower_omp. | 
 |    Operand 3: OMP_PARALLEL_DATA_ARG: Local variable in the parent | 
 | 	      function containing data to be shared with the child | 
 | 	      function.  */ | 
 |  | 
 | DEFTREECODE (OMP_PARALLEL, "omp_parallel", tcc_statement, 4) | 
 |  | 
 | /* OpenMP - #pragma omp for [clause1 ... clauseN] | 
 |    Operand 0: OMP_FOR_BODY: Loop body. | 
 |    Operand 1: OMP_FOR_CLAUSES: List of clauses. | 
 |    Operand 2: OMP_FOR_INIT: Initialization code of the form | 
 |                              	VAR = N1. | 
 |    Operand 3: OMP_FOR_COND: Loop conditional expression of the form | 
 |                              	VAR { <, >, <=, >= } N2. | 
 |    Operand 4: OMP_FOR_INCR: Loop index increment of the form | 
 | 			     	VAR { +=, -= } INCR. | 
 |    Operand 5: OMP_FOR_PRE_BODY: Filled by the gimplifier with things | 
 | 	from INIT, COND, and INCR that are technically part of the | 
 | 	OMP_FOR structured block, but are evaluated before the loop | 
 | 	body begins. | 
 |  | 
 |    VAR must be a signed integer variable, which is implicitly thread | 
 |    private.  N1, N2 and INCR are required to be loop invariant integer | 
 |    expressions that are evaluated without any synchronization. | 
 |    The evaluation order, frequency of evaluation and side-effects are | 
 |    unspecified by the standard.  */ | 
 | DEFTREECODE (OMP_FOR, "omp_for", tcc_statement, 6) | 
 |  | 
 | /* OpenMP - #pragma omp sections [clause1 ... clauseN] | 
 |    Operand 0: OMP_SECTIONS_BODY: Sections body. | 
 |    Operand 1: OMP_SECTIONS_CLAUSES: List of clauses.  */ | 
 | DEFTREECODE (OMP_SECTIONS, "omp_sections", tcc_statement, 2) | 
 |  | 
 | /* OpenMP - #pragma omp single | 
 |    Operand 0: OMP_SINGLE_BODY: Single section body. | 
 |    Operand 1: OMP_SINGLE_CLAUSES: List of clauses.  */ | 
 | DEFTREECODE (OMP_SINGLE, "omp_single", tcc_statement, 2) | 
 |  | 
 | /* OpenMP - #pragma omp section | 
 |    Operand 0: OMP_SECTION_BODY: Section body.  */ | 
 | DEFTREECODE (OMP_SECTION, "omp_section", tcc_statement, 1) | 
 |  | 
 | /* OpenMP - #pragma omp master | 
 |    Operand 0: OMP_MASTER_BODY: Master section body.  */ | 
 | DEFTREECODE (OMP_MASTER, "omp_master", tcc_statement, 1) | 
 |  | 
 | /* OpenMP - #pragma omp ordered | 
 |    Operand 0: OMP_ORDERED_BODY: Master section body.  */ | 
 | DEFTREECODE (OMP_ORDERED, "omp_ordered", tcc_statement, 1) | 
 |  | 
 | /* OpenMP - #pragma omp critical [name] | 
 |    Operand 0: OMP_CRITICAL_BODY: Critical section body. | 
 |    Operand 1: OMP_CRITICAL_NAME: Identifier for critical section.  */ | 
 | DEFTREECODE (OMP_CRITICAL, "omp_critical", tcc_statement, 2) | 
 |  | 
 | /* Return from an OpenMP directive.  */ | 
 | DEFTREECODE (OMP_RETURN, "omp_return", tcc_statement, 0) | 
 |  | 
 | /* OpenMP - An intermediate tree code to mark the location of the | 
 |    loop or sections iteration in the partially lowered code.  */ | 
 | DEFTREECODE (OMP_CONTINUE, "omp_continue", tcc_statement, 0) | 
 |  | 
 | /* OpenMP - #pragma omp atomic | 
 |    Operand 0: The address at which the atomic operation is to be performed. | 
 | 	This address should be stabilized with save_expr. | 
 |    Operand 1: The expression to evaluate.  When the old value of the object | 
 | 	at the address is used in the expression, it should appear as if | 
 | 	build_fold_indirect_ref of the address.  */ | 
 | DEFTREECODE (OMP_ATOMIC, "omp_atomic", tcc_statement, 2) | 
 |  | 
 | /* OpenMP clauses.  */ | 
 | DEFTREECODE (OMP_CLAUSE, "omp_clause", tcc_exceptional, 0) | 
 |  | 
 | /* Reduction operations.  | 
 |    Operations that take a vector of elements and "reduce" it to a scalar | 
 |    result (e.g. summing the elements of the vector, finding the minimum over | 
 |    the vector elements, etc). | 
 |    Operand 0 is a vector; the first element in the vector has the result. | 
 |    Operand 1 is a vector.  */  | 
 | DEFTREECODE (REDUC_MAX_EXPR, "reduc_max_expr", tcc_unary, 1) | 
 | DEFTREECODE (REDUC_MIN_EXPR, "reduc_min_expr", tcc_unary, 1) | 
 | DEFTREECODE (REDUC_PLUS_EXPR, "reduc_plus_expr", tcc_unary, 1) | 
 |  | 
 | /* Widenning dot-product. | 
 |    The first two arguments are of type t1. | 
 |    The third argument and the result are of type t2, such that t2 is at least | 
 |    twice the size of t1. DOT_PROD_EXPR(arg1,arg2,arg3) is equivalent to: | 
 |    	tmp = WIDEN_MULT_EXPR(arg1, arg2); | 
 |    	arg3 = PLUS_EXPR (tmp, arg3); | 
 |    or:  | 
 | 	tmp = WIDEN_MULT_EXPR(arg1, arg2); | 
 |         arg3 = WIDEN_SUM_EXPR (tmp, arg3);		 */ | 
 | DEFTREECODE (DOT_PROD_EXPR, "dot_prod_expr", tcc_expression, 3) | 
 |  | 
 | /* Widenning summation. | 
 |    The first argument is of type t1. | 
 |    The second argument is of type t2, such that t2 is at least twice | 
 |    the size of t1. The type of the entire expression is also t2. | 
 |    WIDEN_SUM_EXPR is equivalent to first widening (promoting) | 
 |    the first argument from type t1 to type t2, and then summing it | 
 |    with the second argument.  */ | 
 | DEFTREECODE (WIDEN_SUM_EXPR, "widen_sum_expr", tcc_binary, 2) | 
 |     | 
 | /* Widenning multiplication.  | 
 |    The two arguments are of type t1. | 
 |    The result is of type t2, such that t2 is at least twice | 
 |    the size of t1. WIDEN_MULT_EXPR is equivalent to first widening (promoting) | 
 |    the arguments from type t1 to type t2, and then multiplying them.  */ | 
 | DEFTREECODE (WIDEN_MULT_EXPR, "widen_mult_expr", tcc_binary, 2) | 
 |  | 
 | /* Whole vector left/right shift in bits. | 
 |    Operand 0 is a vector to be shifted. | 
 |    Operand 1 is an integer shift amount in bits.  */ | 
 | DEFTREECODE (VEC_LSHIFT_EXPR, "vec_lshift_expr", tcc_binary, 2) | 
 | DEFTREECODE (VEC_RSHIFT_EXPR, "vec_rshift_expr", tcc_binary, 2) | 
 |  | 
 | /* | 
 | Local variables: | 
 | mode:c | 
 | End: | 
 | */ |