On 12/23/15 09:48, Nathan Sidwell wrote:
On 12/21/15 14:45, Jeff Law wrote:
With some kind of comment in decl_in_symtab_p indicating why we need to check
and filter on !DECL_IN_CONSTANT_POOL this is OK.
Done, thanks. (I half guessed HPPA might be such a port :)
sigh, there are other routes by which constpool entries get into the varpool,
and it appears other checks using symtab_in_varpool_p to figure out whether they
need to do something. Leading to powerpc having a problem.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69033
powerpc inserts an array initializer constant pool entry into the varpool via
tree_output_constant_def (varasm.c), that has an explicit call to:
varpool_node::finalize_decl (decl);
so it seems intentional that constpool objects can end up also in the varpool.
I notice that via this route varpool thinks the constant's value is available,
which is different to the behaviour when insertionwas via alias checking.
So, I think that either
1) alias checking shouldn't create varpool entries (i.e. use varpool::get rather
than varpool::get_create). It wouldn't need to use the symtab_in_varpool_p
predicate in that case.
2) Or varpool::get_create should take note of DECL_IN_CONSTANT_POOL and declare
the value available
3) or build_constant_desc (varasm.c) should explicitly put the constant in the
varpool, to match tree_output_constant_def?
I have reverted the cgraph.h change and am experimenting with option #1
nathan
2015-12-23 Nathan Sidwell <nat...@acm.org>
gcc/
* cgraph.h (decl_in_symtab_p): Revert check DECL_IN_CONSTANT_POOL.
gcc/testsuite/
* gcc.dg/alias-15.c: Revert.
Index: cgraph.h
===================================================================
--- cgraph.h (revision 231929)
+++ cgraph.h (working copy)
@@ -2294,19 +2294,13 @@ symtab_node::real_symbol_p (void)
}
/* Return true if DECL should have entry in symbol table if used.
- Those are functions and static & external non-constpool variables.
- We do not expect constant pool variables in the varpool, as they're
- not related to other variables, and simply lazily inserting them
- using the regular interface results in varpool thinking they are
- externally provided -- which results in erroneous assembly emission
- as an undefined decl. */
+ Those are functions and static & external veriables*/
static inline bool
decl_in_symtab_p (const_tree decl)
{
return (TREE_CODE (decl) == FUNCTION_DECL
|| (TREE_CODE (decl) == VAR_DECL
- && !DECL_IN_CONSTANT_POOL (decl)
&& (TREE_STATIC (decl) || DECL_EXTERNAL (decl))));
}
Index: testsuite/gcc.dg/alias-15.c
===================================================================
--- testsuite/gcc.dg/alias-15.c (revision 231929)
+++ testsuite/gcc.dg/alias-15.c (working copy)
@@ -1,15 +0,0 @@
-/* { dg-do compile } */
-/* { dg-additional-options "-O2 -fdump-ipa-cgraph" } */
-
-/* RTL-level CSE shouldn't introduce LCO (for the string) into varpool */
-char *p;
-
-void foo ()
-{
- p = "abc\n";
-
- while (*p != '\n')
- p++;
-}
-
-/* { dg-final { scan-ipa-dump-not "LC0" "cgraph" } } */
