From a70f5987c4ae6de9f238eacd636f07305ce76d73 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 31 Mar 2009 23:34:30 -0400
Subject: [PATCH] re PR c++/34691 (Default argument checking not performed
 after overload resolution with C linkage)

        PR c++/34691
        * name-lookup.c (pushdecl_maybe_friend): Diagnose mismatched
        extern C declarations.

        * libsupc++/unwind-cxx.h: Correct __cxa_call_terminate prototype.

From-SVN: r145386
---
 gcc/cp/ChangeLog                              |  4 ++++
 gcc/cp/name-lookup.c                          | 18 ++++++++++++++++--
 gcc/testsuite/ChangeLog                       |  4 ++++
 gcc/testsuite/g++.old-deja/g++.other/using9.C |  4 ++--
 libstdc++-v3/ChangeLog                        |  2 ++
 libstdc++-v3/libsupc++/unwind-cxx.h           |  2 +-
 6 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index adb5be358ad..5b5268157e3 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2009-03-31  Jason Merrill  <jason@redhat.com>
 
+	PR c++/34691
+	* name-lookup.c (pushdecl_maybe_friend): Diagnose mismatched
+	extern "C" declarations.
+
 	C++ DR 613
 	* semantics.c (finish_non_static_data_member): Allow such references
 	without an associated object in sizeof/decltype/alignof.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 5a92dc6ed89..277de78b420 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -778,12 +778,18 @@ pushdecl_maybe_friend (tree x, bool is_friend)
       if ((TREE_CODE (x) == FUNCTION_DECL)
 	  && DECL_EXTERN_C_P (x)
           /* We should ignore declarations happening in system headers.  */
+	  && !DECL_ARTIFICIAL (x)
 	  && !DECL_IN_SYSTEM_HEADER (x))
 	{
 	  cxx_binding *function_binding =
 	      lookup_extern_c_fun_binding_in_all_ns (x);
-	  if (function_binding
-              && !DECL_IN_SYSTEM_HEADER (function_binding->value))
+	  tree previous = (function_binding
+			   ? function_binding->value
+			   : NULL_TREE);
+	  if (previous
+	      && !DECL_ARTIFICIAL (previous)
+              && !DECL_IN_SYSTEM_HEADER (previous)
+	      && DECL_CONTEXT (previous) != DECL_CONTEXT (x))
 	    {
 	      tree previous = function_binding->value;
 
@@ -810,6 +816,14 @@ pushdecl_maybe_friend (tree x, bool is_friend)
 		      POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node);
 		    }
 		}
+	      else
+		{
+		  pedwarn (input_location, 0,
+			   "declaration of %q#D with C language linkage", x);
+		  pedwarn (input_location, 0,
+			   "conflicts with previous declaration %q+#D",
+			   previous);
+		}
 	    }
 	}
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 00dbf448019..6e723c3ec5c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2009-03-31  Jason Merrill  <jason@redhat.com>
+
+	* g++.old-deja/g++.other/using9.C: Add expected errors.
+
 2009-03-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.c-torture/compile/pr33009.c: Removed.
diff --git a/gcc/testsuite/g++.old-deja/g++.other/using9.C b/gcc/testsuite/g++.old-deja/g++.other/using9.C
index 9779f72d861..0e34156d8f6 100644
--- a/gcc/testsuite/g++.old-deja/g++.other/using9.C
+++ b/gcc/testsuite/g++.old-deja/g++.other/using9.C
@@ -13,9 +13,9 @@ struct x {};
 using ::x;
 using ::a;
 
-extern "C" void foo ();
+extern "C" void foo ();		// { dg-error "previous declaration" }
 
 namespace {
-  extern "C" int foo ();
+  extern "C" int foo ();	// { dg-error "C.*linkage" }
   using ::foo; // { dg-error "" } already in use
 }
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 1bcfc0b8045..27c8848822c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,7 @@
 2009-03-31  Jason Merrill  <jason@redhat.com>
 
+	* libsupc++/unwind-cxx.h: Correct __cxa_call_terminate prototype.
+
 	PR libstdc++/39310
 	* include/tr1_impl/type_traits (is_function): Add partial
 	specializations with function cv-quals.
diff --git a/libstdc++-v3/libsupc++/unwind-cxx.h b/libstdc++-v3/libsupc++/unwind-cxx.h
index 3e2cf0f00b4..ee42f6ad14e 100644
--- a/libstdc++-v3/libsupc++/unwind-cxx.h
+++ b/libstdc++-v3/libsupc++/unwind-cxx.h
@@ -192,7 +192,7 @@ extern "C" void __cxa_bad_typeid ();
 // throws, and if bad_exception needs to be thrown.  Called from the
 // compiler.
 extern "C" void __cxa_call_unexpected (void *) __attribute__((noreturn));
-extern "C" void __cxa_call_terminate (void*) __attribute__((noreturn));
+extern "C" void __cxa_call_terminate (_Unwind_Exception*) __attribute__((noreturn));
 
 #ifdef __ARM_EABI_UNWINDER__
 // Arm EABI specified routines.