https://gcc.gnu.org/g:1b34664c6255a7c1802e377be439f0d474dde0bb
commit r16-3218-g1b34664c6255a7c1802e377be439f0d474dde0bb
Author: Qing Zhao <qing.z...@oracle.com>
Date: Thu Aug 14 20:27:20 2025 +0000
Generate a call to a .ACCESS_WITH_SIZE for a FAM with counted_by attribute
only when it's read from.
Currently, we generate a call to a .ACCESS_WITH_SIZE for a FAM with
counted_by
attribute for every component_ref that corresponds to such an object.
Actually, such .ACCESS_WITH_SIZE calls are useless when they are generated
for a written site or an address taken site.
In this patch, we only generate a call to .ACCESS_WITH_SIZE for a FAM with
counted_by attribute when it's a read.
gcc/c/ChangeLog:
* c-tree.h (handle_counted_by_for_component_ref): New prototype of
build_component_ref and handle_counted_by_for_component_ref.
* c-parser.cc (c_parser_postfix_expression): Call the new prototypes
of build_component_ref and handle_counted_by_for_component_ref,
update comments.
* c-typeck.cc (default_function_array_read_conversion): Likewise.
(convert_lvalue_to_rvalue): Likewise.
(default_conversion): Likewise.
(handle_counted_by_p): Update comments.
(handle_counted_by_for_component_ref): Delete one argument.
(build_component_ref): Delete one argument. Delete the call to
handle_counted_by_for_component_ref completely.
(build_array_ref): Generate call to .ACCESS_WITH_SIZE for array.
gcc/testsuite/ChangeLog:
* gcc.dg/flex-array-counted-by-2.c: Adjust testing case.
Diff:
---
gcc/c/c-parser.cc | 14 +++-------
gcc/c/c-tree.h | 4 +--
gcc/c/c-typeck.cc | 38 ++++++++++----------------
gcc/testsuite/gcc.dg/flex-array-counted-by-2.c | 2 +-
4 files changed, 21 insertions(+), 37 deletions(-)
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 148cd9aee5f0..510d7272d384 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -11876,12 +11876,9 @@ c_parser_postfix_expression (c_parser *parser)
if (c_parser_next_token_is (parser, CPP_NAME))
{
c_token *comp_tok = c_parser_peek_token (parser);
- /* Ignore the counted_by attribute for reference inside
- offsetof since the information is not useful at all. */
offsetof_ref
= build_component_ref (loc, offsetof_ref, comp_tok->value,
- comp_tok->location, UNKNOWN_LOCATION,
- false);
+ comp_tok->location, UNKNOWN_LOCATION);
c_parser_consume_token (parser);
while (c_parser_next_token_is (parser, CPP_DOT)
|| c_parser_next_token_is (parser,
@@ -11908,14 +11905,11 @@ c_parser_postfix_expression (c_parser *parser)
break;
}
c_token *comp_tok = c_parser_peek_token (parser);
- /* Ignore the counted_by attribute for reference inside
- offsetof since the information is not useful. */
offsetof_ref
= build_component_ref (loc, offsetof_ref,
comp_tok->value,
comp_tok->location,
- UNKNOWN_LOCATION,
- false);
+ UNKNOWN_LOCATION);
c_parser_consume_token (parser);
}
else
@@ -12701,8 +12695,8 @@ c_parser_postfix_expression (c_parser *parser)
/* If the array ref is inside TYPEOF or ALIGNOF, the call to
.ACCESS_WITH_SIZE was not generated by the routine
build_component_ref by default, we should generate it here. */
- if ((in_typeof || in_alignof) && TREE_CODE (ref) == COMPONENT_REF)
- ref = handle_counted_by_for_component_ref (loc, ref, false);
+ if (TREE_CODE (ref) == COMPONENT_REF)
+ ref = handle_counted_by_for_component_ref (loc, ref);
if (has_counted_by_object (ref))
expr.value = get_counted_by_ref (ref);
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index b8c81f6be7b5..afec03e25ebc 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -821,8 +821,8 @@ extern void mark_exp_read (tree);
extern tree composite_type (tree, tree);
extern tree lookup_field (const_tree, tree);
extern tree build_component_ref (location_t, tree, tree, location_t,
- location_t, bool = true);
-extern tree handle_counted_by_for_component_ref (location_t, tree, bool);
+ location_t);
+extern tree handle_counted_by_for_component_ref (location_t, tree);
extern tree build_array_ref (location_t, tree, tree);
extern tree build_omp_array_section (location_t, tree, tree, tree);
extern tree build_external_ref (location_t, tree, bool, tree *);
diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 9ea58e1a0c97..3c6f7d996e95 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -2487,11 +2487,10 @@ struct c_expr
default_function_array_read_conversion (location_t loc, struct c_expr exp)
{
mark_exp_read (exp.value);
- /* We only generate a call to .ACCESS_WITH_SIZE for a pointer field when
- it is a read. */
+ /* We only generate a call to .ACCESS_WITH_SIZE when it is a read. */
if (TREE_CODE (exp.value) == COMPONENT_REF
&& handle_counted_by_p (exp.value))
- exp.value = handle_counted_by_for_component_ref (loc, exp.value, true);
+ exp.value = handle_counted_by_for_component_ref (loc, exp.value);
return default_function_array_conversion (loc, exp);
}
@@ -2593,11 +2592,10 @@ convert_lvalue_to_rvalue (location_t loc, struct c_expr
exp,
bool force_non_npc = false;
if (read_p)
mark_exp_read (exp.value);
- /* We only generate a call to .ACCESS_WITH_SIZE for a pointer field when
- it is a read. */
+ /* We only generate a call to .ACCESS_WITH_SIZE when it is a read. */
if (read_p && TREE_CODE (exp.value) == COMPONENT_REF
&& handle_counted_by_p (exp.value))
- exp.value = handle_counted_by_for_component_ref (loc, exp.value, true);
+ exp.value = handle_counted_by_for_component_ref (loc, exp.value);
if (convert_p)
exp = default_function_array_conversion (loc, exp);
@@ -2776,11 +2774,10 @@ default_conversion (tree exp)
tree promoted_type;
mark_exp_read (exp);
- /* We only generate a call to .ACCESS_WITH_SIZE for a pointer field when
- it is a read. */
+ /* We only generate a call to .ACCESS_WITH_SIZE when it is a read. */
if (TREE_CODE (exp) == COMPONENT_REF
&& handle_counted_by_p (exp))
- exp = handle_counted_by_for_component_ref (EXPR_LOCATION (exp), exp, true);
+ exp = handle_counted_by_for_component_ref (EXPR_LOCATION (exp), exp);
/* Functions and arrays have been converted during parsing. */
gcc_assert (code != FUNCTION_TYPE);
@@ -3193,12 +3190,10 @@ build_access_with_size_for_counted_by (location_t loc,
tree ref,
/* For the COMPONENT_REF ref, check whether it has a counted_by attribute,
if so, wrap this COMPONENT_REF with the corresponding CALL to the
function .ACCESS_WITH_SIZE.
- Otherwise, return the ref itself.
- FOR_POINTER is true when this is for pointer field. */
+ Otherwise, return the ref itself. */
tree
-handle_counted_by_for_component_ref (location_t loc, tree ref,
- bool for_pointer)
+handle_counted_by_for_component_ref (location_t loc, tree ref)
{
gcc_assert (TREE_CODE (ref) == COMPONENT_REF);
tree datum = TREE_OPERAND (ref, 0);
@@ -3209,11 +3204,6 @@ handle_counted_by_for_component_ref (location_t loc,
tree ref,
|| TREE_CODE (TREE_TYPE (ref)) == POINTER_TYPE))
return ref;
- bool is_fam = c_flexible_array_member_type_p (TREE_TYPE (ref));
-
- if (!(is_fam ^ for_pointer))
- return ref;
-
tree counted_by_ref = build_counted_by_ref (datum, subdatum,
&counted_by_type);
if (counted_by_ref)
@@ -3233,8 +3223,7 @@ handle_counted_by_for_component_ref (location_t loc, tree
ref,
tree
build_component_ref (location_t loc, tree datum, tree component,
- location_t component_loc, location_t arrow_loc,
- bool handle_counted_by)
+ location_t component_loc, location_t arrow_loc)
{
tree type = TREE_TYPE (datum);
enum tree_code code = TREE_CODE (type);
@@ -3306,8 +3295,6 @@ build_component_ref (location_t loc, tree datum, tree
component,
int quals;
tree subtype;
bool use_datum_quals;
- /* Do not handle counted_by when in typeof and alignof operator. */
- handle_counted_by = handle_counted_by && !in_typeof && !in_alignof;
if (TREE_TYPE (subdatum) == error_mark_node)
return error_mark_node;
@@ -3329,8 +3316,6 @@ build_component_ref (location_t loc, tree datum, tree
component,
SET_EXPR_LOCATION (ref, loc);
check_counted_by_attribute (loc, ref);
- if (handle_counted_by)
- ref = handle_counted_by_for_component_ref (loc, ref, false);
if (TREE_READONLY (subdatum)
|| (use_datum_quals && TREE_READONLY (datum)))
@@ -3517,6 +3502,11 @@ build_array_ref (location_t loc, tree array, tree index)
bool was_vector = VECTOR_TYPE_P (TREE_TYPE (array));
bool non_lvalue = convert_vector_to_array_for_subscript (loc, &array, index);
+ /* We only generate a call to .ACCESS_WITH_SIZE when it is a read. */
+ if (TREE_CODE (array) == COMPONENT_REF
+ && handle_counted_by_p (array))
+ array = handle_counted_by_for_component_ref (loc, array);
+
if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
{
tree rval, type;
diff --git a/gcc/testsuite/gcc.dg/flex-array-counted-by-2.c
b/gcc/testsuite/gcc.dg/flex-array-counted-by-2.c
index 42d6436cec2c..a9bec2d17932 100644
--- a/gcc/testsuite/gcc.dg/flex-array-counted-by-2.c
+++ b/gcc/testsuite/gcc.dg/flex-array-counted-by-2.c
@@ -111,4 +111,4 @@ int main(int argc, char *argv[])
return 0;
}
-/* { dg-final { scan-tree-dump-times "ACCESS_WITH_SIZE" 8 "original" } } */
+/* { dg-final { scan-tree-dump-times "ACCESS_WITH_SIZE" 6 "original" } } */
