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Re: PATCH [C}: tree.h decls for bounded pointers
Oops. Forgot to mention: with the single adjustment below, it bootstraps
on i686-pc-linux-gnu with no regressions from `make check'.
The original patch had this:
+ #define MAYBE_BOUNDED_INDIRECT_TYPE_P(TYPE) \
+ (INDIRECT_TYPE_P (TYPE) || BOUNDED_INDIRECT_TYPE_P (TYPE))
which needs to be this:
+ #define MAYBE_BOUNDED_INDIRECT_TYPE_P(TYPE) \
+ (POINTER_TYPE_P (TYPE) || BOUNDED_INDIRECT_TYPE_P (TYPE))
Here's a revised patch:
2000-03-16 Greg McGary <gkm@gnu.org>
* tree.h (tree_common): Add bounded_flag member. Remove
inaccurate comment about number of remaining bits.
(BOUNDED_INDIRECT_TYPE_P, BOUNDED_POINTER_TYPE_P,
BOUNDED_REFERENCE_TYPE_P, MAYBE_BOUNDED_INDIRECT_TYPE_P,
MAYBE_BOUNDED_POINTER_TYPE_P, MAYBE_BOUNDED_REFERENCE_TYPE_P,
TREE_BOUNDED, TYPE_MAIN_VARIANTS_PHYSICALLY_EQUAL_P,
TYPE_MAIN_PHYSICAL_VARIANT, TYPE_BOUNDED): New macros.
(TYPE_QUAL_BOUNDED): New constant.
(TYPE_QUALS): Handle bounded qualifier.
(TREE_EXPR_QUALS, TREE_FUNC_QUALS): New macros.
(TYPE_BOUNDED_VALUE, TYPE_BOUNDED_BASE, TYPE_BOUNDED_EXTENT,
TYPE_BOUNDED_SUBTYPE, TYPE_UNBOUNDED_VARIANT, TYPE_POINTER_DEPTH,
TYPE_AMBIENT_BOUNDEDNESS): New macros.
(MAX_POINTER_DEPTH, VA_LIST_POINTER_DEPTH): New constants.
(tree_type): Add pointer_depth member. Remove
inaccurate comment about number of remaining bits.
(DECL_POINTER_DEPTH): Add macro.
(tree_decl): Add pointer_depth member.
Index: tree.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/tree.h,v
retrieving revision 1.142
diff -u -p -c -r1.142 tree.h
*** tree.h 2000/03/13 22:54:03 1.142
--- tree.h 2000/03/22 23:15:29
*************** struct tree_common
*** 211,216 ****
--- 211,217 ----
unsigned public_flag : 1;
unsigned private_flag : 1;
unsigned protected_flag : 1;
+ unsigned bounded_flag : 1;
unsigned lang_flag_0 : 1;
unsigned lang_flag_1 : 1;
*************** struct tree_common
*** 219,226 ****
unsigned lang_flag_4 : 1;
unsigned lang_flag_5 : 1;
unsigned lang_flag_6 : 1;
-
- /* There is room for three more flags. */
};
/* The following table lists the uses of each of the above flags and
--- 220,225 ----
*************** struct tree_common
*** 326,333 ****
TREE_NOTHROW in
CALL_EXPR, FUNCTION_DECL
- */
/* Define accessors for the fields that all tree nodes have
(though some fields are not used for all kinds of nodes). */
--- 325,339 ----
TREE_NOTHROW in
CALL_EXPR, FUNCTION_DECL
+
+ bounded_flag:
+
+ TREE_BOUNDED in
+ expressions, VAR_DECL, PARM_DECL, FIELD_DECL, FUNCTION_DECL
+ TYPE_BOUNDED in
+ ..._TYPE
+ */
/* Define accessors for the fields that all tree nodes have
(though some fields are not used for all kinds of nodes). */
*************** extern void tree_class_check_failed PARA
*** 463,473 ****
|| TREE_CODE (TYPE) == UNION_TYPE || TREE_CODE (TYPE) == QUAL_UNION_TYPE \
|| TREE_CODE (TYPE) == SET_TYPE)
! /* Nonzero if TYPE represents a pointer type. */
#define POINTER_TYPE_P(TYPE) \
(TREE_CODE (TYPE) == POINTER_TYPE || TREE_CODE (TYPE) == REFERENCE_TYPE)
/* Nonzero if TYPE represents a type. */
#define TYPE_P(TYPE) (TREE_CODE_CLASS (TREE_CODE (TYPE)) == 't')
--- 469,522 ----
|| TREE_CODE (TYPE) == UNION_TYPE || TREE_CODE (TYPE) == QUAL_UNION_TYPE \
|| TREE_CODE (TYPE) == SET_TYPE)
! /* Nonzero if TYPE represents an unbounded pointer or unbounded
! reference type. (It should be renamed to INDIRECT_TYPE_P.) */
#define POINTER_TYPE_P(TYPE) \
(TREE_CODE (TYPE) == POINTER_TYPE || TREE_CODE (TYPE) == REFERENCE_TYPE)
+ /* Nonzero if TYPE represents a bounded pointer or bounded reference type. */
+
+ #define BOUNDED_INDIRECT_TYPE_P(TYPE) \
+ (TREE_CODE (TYPE) == RECORD_TYPE && TREE_TYPE (TYPE))
+
+ /* Nonzero if TYPE represents a bounded pointer type. */
+
+ #define BOUNDED_POINTER_TYPE_P(TYPE) \
+ (BOUNDED_INDIRECT_TYPE_P (TYPE) \
+ && TREE_CODE (TYPE_BOUNDED_SUBTYPE (TYPE)) == POINTER_TYPE)
+
+ /* Nonzero if TYPE represents a bounded reference type. Bounded
+ reference types have two specific uses: (1) When a reference is
+ seated to a variable-length RECORD_TYPE that has an array of
+ indeterminate length as its final field. For all other objects, it
+ is sufficient to check bounds at the time the reference is seated,
+ and assume that all future uses of the reference are safe, since
+ the address of references cannot change. (2) When a reference
+ supertype is seated to an subtype object. The bounds "remember"
+ the true size of the complete object, so that subsequent upcasts of
+ the address of the reference will be checked properly (is such a
+ thing valid C++?). */
+
+ #define BOUNDED_REFERENCE_TYPE_P(TYPE) \
+ (BOUNDED_INDIRECT_TYPE_P (TYPE) \
+ && TREE_CODE (TYPE_BOUNDED_SUBTYPE (TYPE)) == REFERENCE_TYPE)
+
+ /* Nonzero if TYPE represents a pointer type, either bounded or unbounded. */
+
+ /* Nonzero if TYPE represents a pointer or reference type, either
+ bounded or unbounded. */
+
+ #define MAYBE_BOUNDED_INDIRECT_TYPE_P(TYPE) \
+ (POINTER_TYPE_P (TYPE) || BOUNDED_INDIRECT_TYPE_P (TYPE))
+
+ #define MAYBE_BOUNDED_POINTER_TYPE_P(TYPE) \
+ (TREE_CODE (TYPE) == POINTER_TYPE || BOUNDED_POINTER_TYPE_P (TYPE))
+
+ /* Nonzero if TYPE represents a reference type, either bounded or unbounded. */
+
+ #define MAYBE_BOUNDED_REFERENCE_TYPE_P(TYPE) \
+ (TREE_CODE (TYPE) == REFERENCE_TYPE || BOUNDED_REFERENCE_TYPE_P (TYPE))
/* Nonzero if TYPE represents a type. */
#define TYPE_P(TYPE) (TREE_CODE_CLASS (TREE_CODE (TYPE)) == 't')
*************** extern void tree_class_check_failed PARA
*** 609,614 ****
--- 658,697 ----
In a BLOCK node, this is BLOCK_HANDLER_BLOCK. */
#define TREE_PROTECTED(NODE) ((NODE)->common.protected_flag)
+ /* In a ..._TYPE node, nonzero means that the type's size and layout,
+ (or the size and layout of its arguments and/or return value in the
+ case of a FUNCTION_TYPE or METHOD_TYPE) was changed by the presence
+ of pointer bounds. Use TYPE_BOUNDED instead of this macro when the
+ node is a type, because eventually we may make that a different
+ bit. TYPE_BOUNDED doesn't mean that this type is a bounded indirect
+ type--use BOUNDED_POINTER_TYPE_P, BOUNDED_REFERENCE_TYPE_P,
+ BOUNDED_INDIRECT_TYPE_P to test for that.
+
+ In a FUNCTION_DECL, nonzero means that the size and layout of one
+ of its arguments and/or return value was changed by the presence of
+ pointer bounds. This value can differ from the value of
+ TYPE_BOUNDED (TREE_TYPE (fundecl)) if the function was implicitly
+ declared, then later called with pointer args, or was declared with
+ a variable argument list and is later called with pointer values in
+ the variable argument list.
+
+ In a VAR_DECL, PARM_DECL or FIELD_DECL, TREE_BOUNDED matches the value
+ of the decl's type's BOUNDED_POINTER_TYPE_P.
+
+ In a CONSTRUCTOR or other expression, nonzero means the value is a
+ bounded pointer. It is insufficient to determine the boundedness
+ of an expression EXP with BOUNDED_POINTER_TYPE_P (TREE_TYPE (EXP)),
+ since we allow pointer to be temporarily cast to integer for
+ rounding up to an alignment boudary in a way that preserves the
+ pointer's bounds.
+
+ In an IDENTIFIER_NODE, nonzero means that the name is prefixed with
+ BP_PREFIX (see varasm.c). This occurs for the DECL_ASSEMBLER_NAME
+ of a function that has bounded pointer(s) for its return type and/or
+ argument type(s). */
+
+ #define TREE_BOUNDED(NODE) ((NODE)->common.bounded_flag)
+
/* These flags are available for each language front end to use internally. */
#define TREE_LANG_FLAG_0(NODE) ((NODE)->common.lang_flag_0)
#define TREE_LANG_FLAG_1(NODE) ((NODE)->common.lang_flag_1)
*************** struct tree_block
*** 853,858 ****
--- 936,961 ----
#define TYPE_OBSTACK(NODE) (TYPE_CHECK (NODE)->type.obstack)
#define TYPE_LANG_SPECIFIC(NODE) (TYPE_CHECK (NODE)->type.lang_specific)
+ /* Indirect types present difficulties because they may be represented
+ as either POINTER_TYPE/REFERENCE_TYPE nodes (unbounded) or as
+ RECORD_TYPE nodes (bounded). Bounded and unbounded pointers might
+ be logically equivalent, but physically different. Simple
+ comparison of the main variant only tells if the types are
+ logically equivalent. Use this predicate to compare for physical
+ equivalency. */
+
+ /* Types have the same main variant, and have the same boundedness. */
+ #define TYPE_MAIN_VARIANTS_PHYSICALLY_EQUAL_P(TYPE1, TYPE2) \
+ (TYPE_MAIN_VARIANT (TYPE1) == TYPE_MAIN_VARIANT (TYPE2) \
+ && TREE_CODE (TYPE1) == TREE_CODE (TYPE2))
+
+ /* Return the type variant that has no qualifiers (i.e., the main variant),
+ except that the boundedness qualifier is preserved. */
+ #define TYPE_MAIN_PHYSICAL_VARIANT(TYPE) \
+ (BOUNDED_POINTER_TYPE_P (TYPE) \
+ ? build_qualified_type (TYPE, TYPE_QUAL_BOUNDED) \
+ : TYPE_MAIN_VARIANT (TYPE))
+
/* For aggregate types, information about this type, as a base type
for itself. Used in a language-dependent way for types that are
neither a RECORD_TYPE, QUAL_UNION_TYPE, nor a UNION_TYPE. */
*************** struct tree_block
*** 904,909 ****
--- 1007,1017 ----
the term. */
#define TYPE_RESTRICT(NODE) (TYPE_CHECK (NODE)->type.restrict_flag)
+ /* If nonzero, this type's size and layout, (or the size and layout of
+ its arguments and/or return value in the case of a FUNCTION_TYPE or
+ METHOD_TYPE) was changed by the presence of pointer bounds. */
+ #define TYPE_BOUNDED(NODE) (TYPE_CHECK (NODE)->common.bounded_flag)
+
/* There is a TYPE_QUAL value for each type qualifier. They can be
combined by bitwise-or to form the complete set of qualifiers for a
type. */
*************** struct tree_block
*** 912,923 ****
#define TYPE_QUAL_CONST 0x1
#define TYPE_QUAL_VOLATILE 0x2
#define TYPE_QUAL_RESTRICT 0x4
/* The set of type qualifiers for this type. */
! #define TYPE_QUALS(NODE) \
! ((TYPE_READONLY(NODE) * TYPE_QUAL_CONST) \
! | (TYPE_VOLATILE(NODE) * TYPE_QUAL_VOLATILE) \
! | (TYPE_RESTRICT(NODE) * TYPE_QUAL_RESTRICT))
/* These flags are available for each language front end to use internally. */
#define TYPE_LANG_FLAG_0(NODE) (TYPE_CHECK (NODE)->type.lang_flag_0)
--- 1020,1044 ----
#define TYPE_QUAL_CONST 0x1
#define TYPE_QUAL_VOLATILE 0x2
#define TYPE_QUAL_RESTRICT 0x4
+ #define TYPE_QUAL_BOUNDED 0x8
/* The set of type qualifiers for this type. */
! #define TYPE_QUALS(NODE) \
! ((TYPE_READONLY (NODE) * TYPE_QUAL_CONST) \
! | (TYPE_VOLATILE (NODE) * TYPE_QUAL_VOLATILE) \
! | (TYPE_RESTRICT (NODE) * TYPE_QUAL_RESTRICT) \
! | (BOUNDED_INDIRECT_TYPE_P (NODE) * TYPE_QUAL_BOUNDED))
!
! /* The set of qualifiers pertinent to an expression node. */
! #define TREE_EXPR_QUALS(NODE) \
! ((TREE_READONLY (NODE) * TYPE_QUAL_CONST) \
! | (TREE_THIS_VOLATILE (NODE) * TYPE_QUAL_VOLATILE) \
! | (TREE_BOUNDED (NODE) * TYPE_QUAL_BOUNDED))
!
! /* The set of qualifiers pertinent to a FUNCTION_DECL node. */
! #define TREE_FUNC_QUALS(NODE) \
! ((TREE_READONLY (NODE) * TYPE_QUAL_CONST) \
! | (TREE_THIS_VOLATILE (NODE) * TYPE_QUAL_VOLATILE))
/* These flags are available for each language front end to use internally. */
#define TYPE_LANG_FLAG_0(NODE) (TYPE_CHECK (NODE)->type.lang_flag_0)
*************** struct tree_block
*** 949,954 ****
--- 1070,1134 ----
compact a way as possible. */
#define TYPE_PACKED(NODE) (TYPE_CHECK (NODE)->type.packed_flag)
+ /* A bounded pointer or bounded reference type (collectively called
+ indirect types) is represented as a RECORD_TYPE node containing
+ three pointer fields whose type is the corresponding unbounded
+ POINTER_TYPE or REFERENCE_TYPE. A RECORD_TYPE node that represents
+ a bounded indirect type differs from a normal RECORD_TYPE node in
+ that its TREE_TYPE is non-NULL and has the pointed-to type just as
+ a POINTER_TYPE or REFERENCE_TYPE node has. The bounded RECORD_TYPE
+ nodes are stored on the same type variant chain alongside the
+ variants of the underlaying indirect types nodes. The main variant
+ of such chains is always the unbounded type. */
+
+ /* Access the field decls of a bounded-pointer type. */
+ #define TYPE_BOUNDED_VALUE(TYPE) TYPE_FIELDS (TYPE)
+ #define TYPE_BOUNDED_BASE(TYPE) TREE_CHAIN (TYPE_BOUNDED_VALUE (TYPE))
+ #define TYPE_BOUNDED_EXTENT(TYPE) TREE_CHAIN (TYPE_BOUNDED_BASE (TYPE))
+
+ /* Access the simple-pointer subtype of a bounded-pointer type. */
+ #define TYPE_BOUNDED_SUBTYPE(TYPE) TREE_TYPE (TYPE_BOUNDED_VALUE (TYPE))
+
+ /* Find the unbounded counterpart to a type, or return TYPE if it is
+ already unbounded. */
+ #define TYPE_UNBOUNDED_VARIANT(TYPE) \
+ (BOUNDED_POINTER_TYPE_P (TYPE) ? TYPE_BOUNDED_SUBTYPE (TYPE) : (TYPE))
+
+ /* This field comprises two bits, for values in the range 0..3:
+
+ depth=0 means that type is a scalar, or an aggregate that contains
+ only depth=0 types, or a function that has only depth=0 types for
+ its return value and argument types.
+
+ depth=1 means that type is a pointer to a depth=0 type, or an
+ aggregate that contains only depth=0 and depth=1 types, or a
+ function that has only depth=0 and depth=1 types for its return
+ value and argument types.
+
+ The meanings of depth=2 and depth=3 are obvious by induction.
+ Varargs functions are depth=3. The type `va_list' is depth=3.
+
+ The purpose of measuring pointer depth of a type is to determine
+ the eligibility of a function for an automatically-generated
+ bounded-pointer thunk. A depth=0 functions needs no thunk. A
+ depth=1 function is eligible for an automatic thunk. Functions
+ with depth 2 or more are too complex to get automatic thunks.
+
+ Function decls also have a pointer_depth field, since we also
+ consider the actual argument types for functions. */
+
+ #define TYPE_POINTER_DEPTH(TYPE) (TYPE_CHECK (TYPE)->type.pointer_depth)
+
+ /* In a FUNCTION_TYPE node, this bit stores the value of
+ default_pointer_boundedness at the time TYPE was created. It is
+ useful for choosing default boundedness of function arguments for
+ non-prototype function decls and for varargs/stdarg lists. */
+
+ #define TYPE_AMBIENT_BOUNDEDNESS(TYPE) (TYPE_CHECK (TYPE)->type.transparent_union_flag)
+
+ #define MAX_POINTER_DEPTH 2
+ #define VA_LIST_POINTER_DEPTH 3
+
struct tree_type
{
char common[sizeof (struct tree_common)];
*************** struct tree_type
*** 971,976 ****
--- 1151,1157 ----
unsigned transparent_union_flag : 1;
unsigned packed_flag : 1;
unsigned restrict_flag : 1;
+ unsigned pointer_depth : 2;
unsigned lang_flag_0 : 1;
unsigned lang_flag_1 : 1;
*************** struct tree_type
*** 979,985 ****
unsigned lang_flag_4 : 1;
unsigned lang_flag_5 : 1;
unsigned lang_flag_6 : 1;
- /* room for 3 more bits */
unsigned int align;
union tree_node *pointer_to;
--- 1160,1165 ----
*************** struct tree_type
*** 1387,1392 ****
--- 1567,1582 ----
#define DECL_POINTER_ALIAS_SET_KNOWN_P(NODE) \
(DECL_POINTER_ALIAS_SET (NODE) != - 1)
+ /* The pointer_depth field comprises two bits for values in the range
+ 0..3. The value is normally equal to TYPE_POINTER_DEPTH of decl's
+ type node, but for functions it migth be greater. For example,
+ this can happen when the function is declared to accept a parameter
+ of type void* (depth=1), but is actually called with an argument of
+ type foo** (depth=2). The function type will get the formal
+ parameter's depth, but the function decl will get the actual
+ argument's depth. */
+ #define DECL_POINTER_DEPTH(DECL) (DECL_CHECK (DECL)->decl.pointer_depth)
+
struct tree_decl
{
char common[sizeof (struct tree_common)];
*************** struct tree_decl
*** 1429,1434 ****
--- 1619,1625 ----
#else
enum built_in_class built_in_class : 2;
#endif
+ unsigned pointer_depth : 2;
unsigned lang_flag_0 : 1;
unsigned lang_flag_1 : 1;