On Mon, 16 Jun 2014, Jan Hubicka wrote:
> > > /* Variables declared 'const' without an initializer
> > > have zero as the initializer if they may not be
> > > overridden at link or run time. */
> > > if (!DECL_INITIAL (real_decl)
> > > && (DECL_EXTERNAL (decl) || decl_replaceable_p (decl)))
> > > return error_mark_node;
> > >
> > > Honza?
> >
> > Indeed, this may be a better place to do it as long as
> > decl_replaceable_p reliably returns true for weak aliases. If so, the
> > following might work:
> >
> > if ((!DECL_INITIAL (real_decl) && DECL_EXTERNAL (decl))
> > || decl_replaceable_p (decl)))
> > return error_mark_node;
> >
> > On the other hand, I might just separate it out into two separate if
> > statements since they should probably have their own comments.
>
> Yep, this looks like correct change. I used to have FIXME on this but
> it seems it went away during some cleanups - the original condition was
> comming from expmed's folding and indeed it looked unsafe to me.
>
> This change is OK with the testcase (if it passes testing)
I'd like to push this topic forward a bit. I've bootstrapped and regtested a
version of the patch based on the initial proposal to check DECL_WEAK. The
approach with decl_replaceable_p looks not that easy; I'll expand in a
followup email.
OK for trunk/branch?
2014-07-22 Rich Felker <dal...@libc.org>
Alexander Monakov <amona...@ispras.ru>
gcc/
PR ipa/61144
* varpool.c (ctor_for_folding): Reject weak data.
gcc/testsuite/
PR ipa/61144
* gcc.dg/special/wkali-3.c: New test.
* gcc.dg/special/wkali-3a.c: Auxiliary file.
diff --git a/gcc/varpool.c b/gcc/varpool.c
index 04ce714..9ef2195 100644
--- a/gcc/varpool.c
+++ b/gcc/varpool.c
@@ -378,6 +378,9 @@ ctor_for_folding (tree decl)
return error_mark_node;
}
+ if (DECL_WEAK (decl) && !DECL_VIRTUAL_P (decl))
+ return error_mark_node;
+
gcc_assert (TREE_CODE (decl) == VAR_DECL);
real_node = node = varpool_get_node (decl);
diff --git a/gcc/testsuite/gcc.dg/special/wkali-3.c
b/gcc/testsuite/gcc.dg/special/wkali-3.c
new file mode 100644
index 0000000..407ace6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/special/wkali-3.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+/* { dg-require-weak "" } */
+/* { dg-require-alias "" } */
+/* { dg-additional-sources "wkali-3a.c" } */
+
+#include <stdlib.h>
+
+static const int dummy = 0;
+extern const int foo __attribute__((__weak__, __alias__("dummy")));
+
+int main(void) {
+
+ if (foo)
+ exit(0);
+ else
+ abort();
+}
diff --git a/gcc/testsuite/gcc.dg/special/wkali-3a.c
b/gcc/testsuite/gcc.dg/special/wkali-3a.c
new file mode 100644
index 0000000..b3bc6a4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/special/wkali-3a.c
@@ -0,0 +1,3 @@
+/* { dg-do run } */
+
+int foo = 1;
