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c++: Add ABI version for PR98481 fix

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The PR98481 fix corrects an ABI regression in GCC 10, but we don't want to
introduce an ABI change in the middle of the GCC 10 cycle.  This patch
introduces ABI v15 for the fix, which will be available but not default in
GCC 10.3; the broken behavior remains in ABI v14.  Compatibility aliases
will not be generated for this change.

gcc/ChangeLog:

	PR c++/98481
	* common.opt: Document v15 and v16.

gcc/c-family/ChangeLog:

	PR c++/98481
	* c-opts.c (c_common_post_options): Bump latest_abi_version.

gcc/cp/ChangeLog:

	PR c++/98481
	* mangle.c (write_expression): Adjust.
	* class.c (find_abi_tags_r): Disable PR98481 fix for ABI v14.
	(mark_abi_tags_r): Likewise.

gcc/testsuite/ChangeLog:

	PR c++/98481
	* g++.dg/abi/abi-tag24a.C: New test.
	* g++.dg/abi/macro0.C: Adjust expected value.
This commit is contained in:
Jason Merrill 2021-03-31 17:48:50 -04:00
parent 584731eced
commit 5f00df5925
6 changed files with 32 additions and 10 deletions
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2
gcc/c-family/c-opts.c
View file

@ -965,7 +965,7 @@ c_common_post_options (const char **pfilename)
/* Change flag_abi_version to be the actual current ABI level, for the
benefit of c_cpp_builtins, and to make comparison simpler. */
const int latest_abi_version = 15;
const int latest_abi_version = 16;
/* Generate compatibility aliases for ABI v11 (7.1) by default. */
const int abi_compat_default = 11;

6
gcc/common.opt
View file

@ -960,7 +960,11 @@ Driver Undocumented
; 14: Corrects the mangling of nullptr expression.
; Default in G++ 10.
;
; 15: Changes the mangling of __alignof__ to be distinct from that of alignof.
; 15: Corrects G++ 10 ABI tag regression [PR98481].
; Available, but not default, in G++ 10.3.
;
; 16: Changes the mangling of __alignof__ to be distinct from that of alignof.
; Adds missing 'on' in mangling of operator names in some cases.
; Default in G++ 11.
;
; Additional positive integers will be assigned as new versions of

6
gcc/cp/class.c
View file

@ -1494,8 +1494,8 @@ mark_or_check_tags (tree t, tree *tp, abi_tag_data *p, bool val)
static tree
find_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
{
if (TYPE_P (*tp) && *walk_subtrees == 1)
/* Tell cp_walk_subtrees to look though typedefs. */
if (TYPE_P (*tp) && *walk_subtrees == 1 && flag_abi_version != 14)
/* Tell cp_walk_subtrees to look though typedefs. [PR98481] */
*walk_subtrees = 2;
if (!OVERLOAD_TYPE_P (*tp))
@ -1518,7 +1518,7 @@ find_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
static tree
mark_abi_tags_r (tree *tp, int *walk_subtrees, void *data)
{
if (TYPE_P (*tp) && *walk_subtrees == 1)
if (TYPE_P (*tp) && *walk_subtrees == 1 && flag_abi_version != 14)
/* Tell cp_walk_subtrees to look though typedefs. */
*walk_subtrees = 2;

8
gcc/cp/mangle.c
View file

@ -3119,9 +3119,9 @@ write_expression (tree expr)
{
if (!ALIGNOF_EXPR_STD_P (expr))
{
if (abi_warn_or_compat_version_crosses (15))
if (abi_warn_or_compat_version_crosses (16))
G.need_abi_warning = true;
if (abi_version_at_least (15))
if (abi_version_at_least (16))
{
/* We used to mangle __alignof__ like alignof. */
write_string ("u11__alignof__");
@ -3350,9 +3350,9 @@ write_expression (tree expr)
tree name = dependent_name (expr);
if (IDENTIFIER_ANY_OP_P (name))
{
if (abi_version_at_least (15))
if (abi_version_at_least (16))
write_string ("on");
if (abi_warn_or_compat_version_crosses (15))
if (abi_warn_or_compat_version_crosses (16))
G.need_abi_warning = 1;
}
write_unqualified_id (name);

18
gcc/testsuite/g++.dg/abi/abi-tag24a.C Normal file
View file

@ -0,0 +1,18 @@
// PR c++/98481
// { dg-do compile { target c++11 } }
// { dg-additional-options -fabi-version=14 }
inline namespace N __attribute ((__abi_tag__ ("myabi")))
{
struct A {};
}
template <typename T>
struct B { typedef int size_type; };
struct S1 { B<A>::size_type foo () const { return 1; } };
struct S2 { B<A>::size_type foo () const; };
int S2::foo () const { return 2; }
int (S1::*f1) () const = &S1::foo;
int (S2::*f2) () const = &S2::foo;
// { dg-final { scan-assembler-not "_ZNK2S13fooEv" } }
// { dg-final { scan-assembler "_ZNK2S23fooEv" } }
// { dg-final { scan-assembler "_ZNK2S13fooB5myabiEv" } }

2
gcc/testsuite/g++.dg/abi/macro0.C
View file

@ -1,6 +1,6 @@
// This testcase will need to be kept in sync with c_common_post_options.
// { dg-options "-fabi-version=0" }
#if __GXX_ABI_VERSION != 1015
#if __GXX_ABI_VERSION != 1016
#error "Incorrect value of __GXX_ABI_VERSION"
#endif