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 <ja...@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.
--- 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;
+}
Jakub
