https://gcc.gnu.org/g:efc795b32417e68acfe531762c7bcf893e6dd672
commit efc795b32417e68acfe531762c7bcf893e6dd672
Author: Thomas Schwinge <tschwi...@baylibre.com>
Date: Wed Mar 19 12:18:26 2025 +0100
C++: Adjust implicit '__cxa_bad_typeid' prototype to reality
In 2001 Subversion r40924 (Git commit
52a11cbfcf0cfb32628b6953588b6af4037ac0b6)
"IA-64 ABI Exception Handling", '__cxa_bad_typeid' changed from
'std::type_info const &' to 'void' return type:
--- libstdc++-v3/libsupc++/exception_support.cc
+++ /dev/null
@@ -1,388 +0,0 @@
-[...]
-// Helpers for rtti. Although these don't return, we give them return
types so
-// that the type system is not broken.
-[...]
-extern "C" std::type_info const &
-__cxa_bad_typeid ()
-{
- [...]
-}
-[...]
--- /dev/null
+++ libstdc++-v3/libsupc++/unwind-cxx.h
@@ -0,0 +1,163 @@
+[...]
+extern "C" void __cxa_bad_typeid ();
+[...]
--- /dev/null
+++ libstdc++-v3/libsupc++/eh_aux_runtime.cc
@@ -0,0 +1,56 @@
+[...]
+extern "C" void
+__cxa_bad_typeid ()
+{
+ [...]
+}
The implicit prototype in the C++ front end however wasn't likewise
adjusted,
and so for nvptx we generate code for 'std::type_info const &' return type:
// BEGIN GLOBAL FUNCTION DECL: __cxa_bad_typeid
.extern .func (.param .u64 %value_out) __cxa_bad_typeid;
{
.param .u64 %value_in;
call (%value_in),__cxa_bad_typeid;
trap;
// (noreturn)
exit;
// (noreturn)
ld.param.u64 %r39,[%value_in];
}
..., which is in conflict with the library code with 'void' return type:
// BEGIN GLOBAL FUNCTION DECL: __cxa_bad_typeid
.visible .func __cxa_bad_typeid;
// BEGIN GLOBAL FUNCTION DEF: __cxa_bad_typeid
.visible .func __cxa_bad_typeid
{
[...]
}
..., and we thus get execution test FAILs for 'g++.dg/rtti/typeid11.C', for
example:
error : Prototype doesn't match for '__cxa_bad_typeid' in 'input file
4 at offset 22204', first defined in 'input file 4 at offset 22204'
nvptx-run: cuLinkAddData failed: unknown error (CUDA_ERROR_UNKNOWN, 999)
With this patched, we get the expected:
// BEGIN GLOBAL FUNCTION DECL: __cxa_bad_typeid
-.extern .func (.param .u64 %value_out) __cxa_bad_typeid;
+.extern .func __cxa_bad_typeid;
{
-.param .u64 %value_in;
-call (%value_in),__cxa_bad_typeid;
+call __cxa_bad_typeid;
trap;
// (noreturn)
exit;
// (noreturn)
-ld.param.u64 %r39,[%value_in];
}
..., and execution test PASSes for a few test cases.
gcc/cp/
* rtti.cc (throw_bad_typeid): Adjust implicit '__cxa_bad_typeid'
prototype to reality. Adjust all users.
Co-authored-by: Jason Merrill <ja...@redhat.com>
(cherry picked from commit bf1aca4a2a5b68ac731d2a0c966f335e7bc0df2c)
Diff:
---
gcc/cp/ChangeLog.omp | 9 +++++++++
gcc/cp/rtti.cc | 18 +++++++-----------
2 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/gcc/cp/ChangeLog.omp b/gcc/cp/ChangeLog.omp
index e37a4344ca47..d581e233f71d 100644
--- a/gcc/cp/ChangeLog.omp
+++ b/gcc/cp/ChangeLog.omp
@@ -1,3 +1,12 @@
+2025-03-27 Thomas Schwinge <tschwi...@baylibre.com>
+
+ Backported from trunk:
+ 2025-03-26 Thomas Schwinge <tschwi...@baylibre.com>
+ Jason Merrill <ja...@redhat.com>
+
+ * rtti.cc (throw_bad_typeid): Adjust implicit '__cxa_bad_typeid'
+ prototype to reality. Adjust all users.
+
2025-03-25 Thomas Schwinge <tschwi...@baylibre.com>
Backported from trunk:
diff --git a/gcc/cp/rtti.cc b/gcc/cp/rtti.cc
index e07cc01fd0ba..99a5e51355b8 100644
--- a/gcc/cp/rtti.cc
+++ b/gcc/cp/rtti.cc
@@ -204,8 +204,7 @@ throw_bad_cast (void)
return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
}
-/* Return an expression for "__cxa_bad_typeid()". The expression
- returned is an lvalue of type "const std::type_info". */
+/* See 'libstdc++-v3/libsupc++/eh_aux_runtime.cc' for '__cxa_bad_typeid'. */
static tree
throw_bad_typeid (void)
@@ -216,11 +215,8 @@ throw_bad_typeid (void)
tree name = get_identifier ("__cxa_bad_typeid");
fn = get_global_binding (name);
if (!fn)
- {
- tree t = build_reference_type (const_type_info_type_node);
- t = build_function_type_list (t, NULL_TREE);
- fn = push_throw_library_fn (name, t);
- }
+ fn = push_throw_library_fn
+ (name, build_function_type_list (void_type_node, NULL_TREE));
}
return build_cxx_call (fn, 0, NULL, tf_warning_or_error);
@@ -259,7 +255,7 @@ get_void_tinfo_ptr (tree type)
otherwise return the static type of the expression. */
static tree
-get_tinfo_decl_dynamic (tree exp, tsubst_flags_t complain)
+get_tinfo_ptr_dynamic (tree exp, tsubst_flags_t complain)
{
tree type;
tree t;
@@ -299,7 +295,7 @@ get_tinfo_decl_dynamic (tree exp, tsubst_flags_t complain)
/* Otherwise return the type_info for the static type of the expr. */
t = get_tinfo_ptr (type);
- return cp_build_fold_indirect_ref (t);
+ return t;
}
static bool
@@ -369,7 +365,7 @@ build_typeid (tree exp, tsubst_flags_t complain)
exp = cp_build_fold_indirect_ref (exp);
}
- exp = get_tinfo_decl_dynamic (exp, complain);
+ exp = get_tinfo_ptr_dynamic (exp, complain);
if (exp == error_mark_node)
return error_mark_node;
@@ -383,7 +379,7 @@ build_typeid (tree exp, tsubst_flags_t complain)
else
mark_type_use (initial_expr);
- return exp;
+ return cp_build_fold_indirect_ref (exp);
}
/* Generate the NTBS name of a type. If MARK_PRIVATE, put a '*' in front so
that
