[Bug middle-end/67868] New: [4.9/5/6 regression] ICE on targets with section anchors.

[Bug middle-end/67868] New: [4.9/5/6 regression] ICE on targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

            Bug ID: 67868
           Summary: [4.9/5/6 regression] ICE on targets with section
                    anchors.
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ramana at gcc dot gnu.org
  Target Milestone: ---

Given this testcase on targets with section anchors. I see the  following ICE
on arm, aarch64 and powerpc targets.

$> cat /tmp/test.c
char _vtable_map_vars_start []
__attribute__ ((__visibility__ ("protected"), used, aligned(4096),
  section(".vtable_map_vars")))
  = { };

$> ./xgcc -B`pwd` -S -O2 /tmp/test.c

/tmp/test.c:5:3: internal compiler error: Segmentation fault
   = { };
   ^
0xa95d6f crash_signal
        ../../gcc-fsf/gcc/toplev.c:353
0xd6faec tree_check(tree_node*, char const*, int, char const*, tree_code)
        ../../gcc-fsf/gcc/tree.h:2863
0xd6faec default_elf_asm_named_section(char const*, unsigned int, tree_node*)
        ../../gcc-fsf/gcc/varasm.c:6303
0xd7191f switch_to_section(section*)
        ../../gcc-fsf/gcc/varasm.c:7144
0xd75603 output_object_block
        ../../gcc-fsf/gcc/varasm.c:7335
0xd75603 output_object_blocks()
        ../../gcc-fsf/gcc/varasm.c:7440
Please submit a full bug report,
with preprocessed source if appropriate.

The reason for the failure appears to be a failure to handle VAR_DECLS in
default_elf_asm_named_section.  Given that switch_to_section essentially passes
a VAR_DECL or a FUNCTION_DECL into targetm.elf_asm_named_section while
targetm.elf_asm_named_section only handles IDENTIFIER_NAMES in it, there is a
clear mismatch in terms of what is passed and what is expected.

I've got a patch that I'm currently testing.

[Bug middle-end/67868] [4.9/5/6 regression] ICE in named section handling on targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
             Target|                            |aarch64*, arm*, powerpc*
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-10-06
            Summary|[4.9/5/6 regression] ICE on |[4.9/5/6 regression] ICE in
                   |targets with section        |named section handling on
                   |anchors.                    |targets with section
                   |                            |anchors.
     Ever confirmed|0                           |1

--- Comment #1 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Confirmed.

[Bug middle-end/67868] [4.9/5/6 regression] ICE in named section handling on targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

--- Comment #2 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
However the ICE is specific to the VTV feature I think and not generally
applicable.

[Bug middle-end/67868] [4.9/5/6 regression] ICE in named section handling on targets with section anchors.

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.9.4

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
What GCC version (with VTV enabled) did work for you?

[Bug other/67868] ICE in handling VTV sections for targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |other
   Target Milestone|4.9.4                       |6.0
            Summary|[4.9/5/6 regression] ICE in |ICE in handling VTV
                   |named section handling on   |sections for targets with
                   |targets with section        |section anchors.
                   |anchors.                    |

--- Comment #4 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Update summary

[Bug other/67868] ICE in handling VTV sections for targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

--- Comment #5 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> What GCC version (with VTV enabled) did work for you?

I do not think any version of GCC with VTV enabled has worked for AArch64 or
ARM - I failed to notice the special casing for .vtable_map_vars in
assemble_variable when I filed the bug.

[Bug other/67868] ICE in handling VTV sections for targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

--- Comment #7 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Author: ramana
Date: Tue Oct 20 10:36:54 2015
New Revision: 229044

URL: https://gcc.gnu.org/viewcvs?rev=229044&root=gcc&view=rev
Log:
Fix VTV for targets with section anchors.


2015-10-20  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

        PR other/67868
        * varasm.c (assemble_variable): Move special vtv handling to..
        (handle_vtv_comdat_sections): .. here. New function.
        (output_object_block): Handle vtv sections.

Modified:
    trunk/gcc/ChangeLog

[Bug other/67868] ICE in handling VTV sections for targets with section anchors.

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67868

--- Comment #8 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Author: ramana
Date: Tue Oct 20 10:39:30 2015
New Revision: 229045

URL: https://gcc.gnu.org/viewcvs?rev=229045&root=gcc&view=rev
Log:
Enable VTV for aarch64 and arm


Requires fix for section anchors with VTV i.e. PR other/67868

2015-10-20  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

        * configure.tgt (aarch64*-*-linux): Enable.
        (arm*-*-linux*): Enable.


Modified:
    trunk/libvtv/ChangeLog
    trunk/libvtv/configure.tgt