tree.def

来自「GCC编译器源代码」· DEF 代码 · 共 747 行 · 第 1/3 页

   32 bits each, giving us a 64 bit constant capability.
   Note: constants of type char in Pascal are INTEGER_CST,
   and so are pointer constants such as nil in Pascal or NULL in C.
   `(int *) 1' in C also results in an INTEGER_CST.  */
DEFTREECODE (INTEGER_CST, "integer_cst", "c", 2)

/* Contents are in TREE_REAL_CST field.  Also there is TREE_CST_RTL.  */
DEFTREECODE (REAL_CST, "real_cst", "c", 3)

/* Contents are in TREE_REALPART and TREE_IMAGPART fields,
   whose contents are other constant nodes.
   Also there is TREE_CST_RTL.  */
DEFTREECODE (COMPLEX_CST, "complex_cst", "c", 3)

/* Contents are TREE_STRING_LENGTH and TREE_STRING_POINTER fields.
   Also there is TREE_CST_RTL.  */
DEFTREECODE (STRING_CST, "string_cst", "c", 3)

/* 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 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_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,
    or it is 0 for a function that returns no value.
    (C functions returning void have zero here.)
   DECL_RESULT_TYPE holds the type in which the result is actually
    returned.  This is usually the same as the type of DECL_RESULT,
    but (1) it may be a wider integer type and
    (2) it remains valid, for the sake of inlining, even after the
    function's compilation is done.
   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 non-zero 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", "d", 0)
DEFTREECODE (LABEL_DECL, "label_decl", "d", 0)
DEFTREECODE (CONST_DECL, "const_decl", "d", 0)
DEFTREECODE (TYPE_DECL, "type_decl", "d", 0)
DEFTREECODE (VAR_DECL, "var_decl", "d", 0)
DEFTREECODE (PARM_DECL, "parm_decl", "d", 0)
DEFTREECODE (RESULT_DECL, "result_decl", "d", 0)
DEFTREECODE (FIELD_DECL, "field_decl", "d", 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).  */
DEFTREECODE (COMPONENT_REF, "component_ref", "r", 2)

/* 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;
   TREE_UNSIGNED says which.  */
DEFTREECODE (BIT_FIELD_REF, "bit_field_ref", "r", 3)
   
/* C unary `*' or Pascal `^'.  One operand, an expression for a pointer.  */
DEFTREECODE (INDIRECT_REF, "indirect_ref", "r", 1)

/* Pascal `^` on a file.  One operand, an expression for the file.  */
DEFTREECODE (BUFFER_REF, "buffer_ref", "r", 1)

/* Array indexing in languages other than C.
   Operand 0 is the array; operand 1 is a list of indices
   stored as a chain of TREE_LIST nodes.  */
DEFTREECODE (ARRAY_REF, "array_ref", "r", 2)

/* Constructor: return an aggregate value made from specified components.
   In C, this is used only for structure and array initializers.
   Also used for SET_TYPE in Chill (and potentially Pascal).
   The first "operand" is really a pointer to the RTL,
   for constant constructors only.
   The second operand is a list of component values
   made out of a chain of TREE_LIST nodes.

   For ARRAY_TYPE:
   The TREE_PURPOSE of each node is the corresponding index.
   If the TREE_PURPOSE is a RANGE_EXPR, it is a short-hand for many nodes,
   one for each index in the range.  (If the corresponding TREE_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 TREE_PURPOSE of each node is a FIELD_DECL.

   For SET_TYPE:
   The TREE_VALUE specifies a value (index) in the set that is true.
   If TREE_PURPOSE is non-NULL, it specifies the lower limit of a
   range of true values.  Elements not listed are false (not in the set).  */
DEFTREECODE (CONSTRUCTOR, "constructor", "e", 2)

/* 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", "e", 2)

/* Assignment expression.  Operand 0 is the what to set; 1, the new value.  */
DEFTREECODE (MODIFY_EXPR, "modify_expr", "e", 2)

/* Initialization expression.  Operand 0 is the variable to initialize;
   Operand 1 is the initializer.  */
DEFTREECODE (INIT_EXPR, "init_expr", "e", 2)

/* For TARGET_EXPR, operand 0 is the target of an initialization,
   operand 1 is the initializer for the target,
   and operand 2 is the cleanup for this node, if any.
   and 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", "e", 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 types, but the types of operands 1 and 2
   must be the same and the same as the the of this expression.  */
DEFTREECODE (COND_EXPR, "cond_expr", "e", 3)

/* Declare local variables, including making RTL and allocating space.
   Operand 0 is a chain of VAR_DECL nodes for the variables.
   Operand 1 is the body, the expression to be computed using 
   the variables.  The value of operand 1 becomes that of the BIND_EXPR.
   Operand 2 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", "e", 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.
   There is no operand 2.  That slot is used for the
   CALL_EXPR_RTL macro (see preexpand_calls).  */
DEFTREECODE (CALL_EXPR, "call_expr", "e", 3)

/* Call a method.  Operand 0 is the method, whose type is a METHOD_TYPE.
   Operand 1 is the expression for "self".
   Operand 2 is the list of explicit arguments.  */
DEFTREECODE (METHOD_CALL_EXPR, "method_call_expr", "e", 4)

/* Specify a value to compute along with its corresponding cleanup.
   Operand 0 argument is an expression whose value needs a cleanup.
   Operand 1 is an RTL_EXPR which will eventually represent that value.
   Operand 2 is the cleanup expression for the object.
     The RTL_EXPR is used in this expression, which is how the expression
     manages to act on the proper value.
   The cleanup is executed by the first enclosing CLEANUP_POINT_EXPR, if
   it exists, otherwise it is the responsibility of the caller to manually
   call expand_start_target_temps/expand_end_target_temps, as needed.

   This differs from TRY_CATCH_EXPR in that operand 2 is always
   evaluated when an exception isn't thrown when cleanups are run.  */
DEFTREECODE (WITH_CLEANUP_EXPR, "with_cleanup_expr", "e", 3)

/* 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", "e", 1)

/* The following two codes are used in languages that have types where
   the position and/or sizes of fields vary from object to object of the
   same type, i.e., where some other field in the object contains a value
   that is used in the computation of another field's offset or size.

   For example, a record type with a discriminant in Ada is such a type.
   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.

   These "self-references" are doing using a PLACEHOLDER_EXPR.  This is a
   node that will later be replaced with the object being referenced.  Its type