[Bug middle-end/61848] [5 Regression] a previous declaration causes the section attribute to be lost

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61848

--- Comment #21 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Author: trippels
Date: Fri Oct 17 05:10:07 2014
New Revision: 216361

URL: https://gcc.gnu.org/viewcvs?rev=216361&root=gcc&view=rev
Log:
Fix pr61848, linux kernel miscompile

This patch cures the linux kernel boot failure when compiled using
trunk gcc.

At its heart, the problem is caused by merge_decls merging from the
old decl to the new decl, then copying back to the old decl and
discarding the new.  When Jan moved some fields to the symtab,
"copying back to the old decl" was lost for those fields.  Really,
it would be best if merge_decls was rewritten to merge everything to
the kept decl, but here I'm just doing that for fields accessed via
decl_with_vis.symtab_node.

2014-10-17  Alan Modra  <amodra@gmail.com>

gcc/c/
    PR middle-end/61848
    * c-decl.c (merge_decls): Don't merge section name or tls model
    to newdecl symtab node, instead merge to olddecl.  Override
    existing olddecl section name.  Set tls_model for all thread-local
    vars, not just OMP thread-private ones.  Remove incorrect comment.
gcc/cp/
    PR middle-end/61848
    * decl.c (merge_decls): Don't merge section name, comdat group or
    tls model to newdecl symtab node, instead merge to olddecl.
    Override existing olddecl section name.  Set tls_model for all
    thread-local vars, not just OMP thread-private ones.  Remove
    incorrect comment.

2014-10-17  Markus Trippelsdorf  <markus@trippelsdorf.de>

    PR middle-end/61848
    * g++.dg/torture/pr61848.C: New testcase.
    * gcc.c-torture/compile/pr61848.c: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/torture/pr61848.C
    trunk/gcc/testsuite/gcc.c-torture/compile/pr61848.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c/c-decl.c
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/testsuite/ChangeLog