GNU Compiler Collection (GCC) Internals: Types for C++

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10.10.1 Types for C++

In C++, an array type is not qualified; rather the type of the array elements is qualified. This situation is reflected in the intermediate representation. The macros described here will always examine the qualification of the underlying element type when applied to an array type. (If the element type is itself an array, then the recursion continues until a non-array type is found, and the qualification of this type is examined.) So, for example, CP_TYPE_CONST_P will hold of the type const int ()[7], denoting an array of seven ints.

The following functions and macros deal with cv-qualification of types:

cp_type_quals

This function returns the set of type qualifiers applied to this type. This value is TYPE_UNQUALIFIED if no qualifiers have been applied. The TYPE_QUAL_CONST bit is set if the type is const-qualified. The TYPE_QUAL_VOLATILE bit is set if the type is volatile-qualified. The TYPE_QUAL_RESTRICT bit is set if the type is restrict-qualified.

CP_TYPE_CONST_P

This macro holds if the type is const-qualified.

CP_TYPE_VOLATILE_P

This macro holds if the type is volatile-qualified.

CP_TYPE_RESTRICT_P

This macro holds if the type is restrict-qualified.

CP_TYPE_CONST_NON_VOLATILE_P

This predicate holds for a type that is const-qualified, but not volatile-qualified; other cv-qualifiers are ignored as well: only the const-ness is tested.

A few other macros and functions are usable with all types:

TYPE_SIZE

The number of bits required to represent the type, represented as an INTEGER_CST. For an incomplete type, TYPE_SIZE will be NULL_TREE.

TYPE_ALIGN

The alignment of the type, in bits, represented as an int.

TYPE_NAME

This macro returns a declaration (in the form of a TYPE_DECL) for the type. (Note this macro does not return an IDENTIFIER_NODE, as you might expect, given its name!) You can look at the DECL_NAME of the TYPE_DECL to obtain the actual name of the type. The TYPE_NAME will be NULL_TREE for a type that is not a built-in type, the result of a typedef, or a named class type.

CP_INTEGRAL_TYPE

This predicate holds if the type is an integral type. Notice that in C++, enumerations are not integral types.

ARITHMETIC_TYPE_P

This predicate holds if the type is an integral type (in the C++ sense) or a floating point type.

CLASS_TYPE_P

This predicate holds for a class-type.

TYPE_BUILT_IN

This predicate holds for a built-in type.

TYPE_PTRDATAMEM_P

This predicate holds if the type is a pointer to data member.

TYPE_PTR_P

This predicate holds if the type is a pointer type, and the pointee is not a data member.

TYPE_PTRFN_P

This predicate holds for a pointer to function type.

TYPE_PTROB_P

This predicate holds for a pointer to object type. Note however that it does not hold for the generic pointer to object type void *. You may use TYPE_PTROBV_P to test for a pointer to object type as well as void *.

The table below describes types specific to C and C++ as well as language-dependent info about GENERIC types.

POINTER_TYPE

Used to represent pointer types, and pointer to data member types. If TREE_TYPE is a pointer to data member type, then TYPE_PTRDATAMEM_P will hold. For a pointer to data member type of the form ‘T X::*’, TYPE_PTRMEM_CLASS_TYPE will be the type X, while TYPE_PTRMEM_POINTED_TO_TYPE will be the type T.

RECORD_TYPE

Used to represent struct and class types in C and C++. If TYPE_PTRMEMFUNC_P holds, then this type is a pointer-to-member type. In that case, the TYPE_PTRMEMFUNC_FN_TYPE is a POINTER_TYPE pointing to a METHOD_TYPE. The METHOD_TYPE is the type of a function pointed to by the pointer-to-member function. If TYPE_PTRMEMFUNC_P does not hold, this type is a class type. For more information, see Classes.

UNKNOWN_TYPE

This node is used to represent a type the knowledge of which is insufficient for a sound processing.

TYPENAME_TYPE

Used to represent a construct of the form typename T::A. The TYPE_CONTEXT is T; the TYPE_NAME is an IDENTIFIER_NODE for A. If the type is specified via a template-id, then TYPENAME_TYPE_FULLNAME yields a TEMPLATE_ID_EXPR. The TREE_TYPE is non-NULL if the node is implicitly generated in support for the implicit typename extension; in which case the TREE_TYPE is a type node for the base-class.

TYPEOF_TYPE

Used to represent the __typeof__ extension. The TYPE_FIELDS is the expression the type of which is being represented.

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