diff mbox series

[C++] Fix ICE with builtin redefinition (PR c++/84843)

Message ID 20180313201746.GC8577@tucnak
State New
Headers show
Series [C++] Fix ICE with builtin redefinition (PR c++/84843) | expand

Commit Message

Jakub Jelinek March 13, 2018, 8:17 p.m. UTC 
Hi!

If we return olddecl on an (invalid) builtin function redefinition rather
than redeclaration, we ICE shortly afterwards, because we assume we have
non-NULL DECL_INITIAL on whatever is returned (except for error_mark_node).

The following patch errors unconditionally for definitions of builtin
functions, and also makes sure to return error_mark_node if we've emitted
an error from the permerror.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2018-03-13  Jakub Jelinek  <jakub@redhat.com>

	PR c++/84843
	* decl.c (duplicate_decls): For redefinition of built-in, use error
	and return error_mark_node.  For redeclaration, return error_mark_node
	rather than olddecl if !flag_permissive.

	* g++.dg/ext/pr84843-1.C: New test.
	* g++.dg/ext/pr84843-2.C: New test.


	Jakub
diff mbox series

Patch

--- gcc/cp/decl.c.jj	2018-03-09 19:00:44.350969146 +0100
+++ gcc/cp/decl.c	2018-03-13 14:56:45.244872506 +0100
@@ -1583,13 +1583,20 @@  next_arg:;
 			  || memcmp (name + len - strlen ("_chk"),
 				     "_chk", strlen ("_chk") + 1) != 0))
 		    {
+		      if (DECL_INITIAL (newdecl))
+			{
+			  error_at (DECL_SOURCE_LOCATION (newdecl),
+				    "definition of %q#D ambiguates built-in "
+				    "declaration %q#D", newdecl, olddecl);
+			  return error_mark_node;
+			}
 		      if (permerror (DECL_SOURCE_LOCATION (newdecl),
 				     "new declaration %q#D ambiguates built-in"
 				     " declaration %q#D", newdecl, olddecl)
 			  && flag_permissive)
 			inform (DECL_SOURCE_LOCATION (newdecl),
 				"ignoring the %q#D declaration", newdecl);
-		      return olddecl;
+		      return flag_permissive ? olddecl : error_mark_node;
 		    }
 		}
 
--- gcc/testsuite/g++.dg/ext/pr84843-1.C.jj	2018-03-13 14:55:15.927831678 +0100
+++ gcc/testsuite/g++.dg/ext/pr84843-1.C	2018-03-13 14:57:51.652902862 +0100
@@ -0,0 +1,9 @@ 
+// PR c++/84843
+// { dg-do compile }
+// { dg-options "-fpermissive" }
+
+extern "C" int
+__atomic_compare_exchange (int x, int y)	// { dg-error "ambiguates built-in declaration" }
+{
+  return x + y;
+}
--- gcc/testsuite/g++.dg/ext/pr84843-2.C.jj	2018-03-13 14:55:19.349833246 +0100
+++ gcc/testsuite/g++.dg/ext/pr84843-2.C	2018-03-13 14:57:58.205905859 +0100
@@ -0,0 +1,9 @@ 
+// PR c++/84843
+// { dg-do compile }
+// { dg-options "" }
+
+extern "C" int
+__atomic_compare_exchange (int x, int y)	// { dg-error "ambiguates built-in declaration" }
+{
+  return x + y;
+}