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 <jason@redhat.com>

1 files changed, 7 insertions, 11 deletions

diff --git a/gcc/cp/rtti.cc b/gcc/cp/rtti.cc
index 158b5ba..3539962 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