[Bug tree-optimization/62032] New: FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[Bug tree-optimization/62032] New: FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker.cheng at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

            Bug ID: 62032
           Summary: FAIL: vsnprintf-chk.c execution,  -O2 -flto
                    -fno-use-linker-plugin -flto-partition=none
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: amker.cheng at gmail dot com

Created attachment 33256
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33256&action=edit
tarball of dump files

Hi,
I monitored below failures on both aarch64-none-elf and arm-none-eabi.
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O2 -flto
-fno-use-linker-plugin -flto-partition=none
FAIL: gcc.c-torture/execute/builtins/vsnprintf-chk.c execution,  -O2 -flto
-fuse-linker-plugin -fno-fat-lto-objects

It's first introduced by r213585, but I am not sure if it's revealed by the
change.  The corresponding (good&bogus) dump files are attached.

arm-none-eabi is configured like:
../gcc/configure --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=arm-none-eabi --prefix=.../trunk-orig/target/ --disable-decimal-float
--disable-libffi --disable-libgomp --disable-libmudflap --disable-libquadmath
--disable-libssp --disable-libstdcxx-pch --disable-nls --disable-shared
--disable-threads --disable-tls --with-gnu-as --with-gnu-ld --with-newlib
--with-headers=yes --with-sysroot=.../trunk-orig/target/arm-none-eabi
--with-host-libstdcxx=... --with-mode=thumb --with-arch=armv7-m
--disable-multilib --enable-lto --enable-languages=c,c++,lto

Thanks.

[Bug tree-optimization/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker.cheng at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

--- Comment #1 from bin.cheng <amker.cheng at gmail dot com> ---
Only fail with lto options.

[Bug tree-optimization/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
      Known to work|                            |4.9.1
           Keywords|                            |lto
   Last reconfirmed|                            |2014-08-06
                 CC|                            |ktkachov at gcc dot gnu.org
     Ever confirmed|0                           |1
   Target Milestone|---                         |4.10.0
      Known to fail|                            |4.10.0

--- Comment #2 from ktkachov at gcc dot gnu.org ---
confirmed, I've noticed this as well.
This seems to appear with LTO

[Bug tree-optimization/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker.cheng at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

--- Comment #3 from bin.cheng <amker.cheng at gmail dot com> ---
I did some investigation and think it's a latent bug of lto which reveaded by
r213585.

Before the revision, pass_fold_builtins::execute calls gimple_fold_builtins
directly to fold __builtin___vsnprintf_chk (_26, _25, 0, 4294967295, "%d - %c",
ap);.  It works fine by simplifying the builtin into __builtin_vsnprintf (_26,
_25, "%d - %c", ap);.

After the revision, it calls to
fold_stmt->gimple_fold_call->gimple_fold_builtin to do the job.  But before
that, it calls gimple_call_builtin_p to verify that it IS a valid builtin call,
which in turn calls gimple_builtin_call_types_compatible_p to check that types
between parameter and argument match each other.  Well, the check fails on the
last parameter/argument, as dumped below:

TREE_TYPE of ARGUMENT:
 <record_type 0x7fc34cc9fc78 va_list SI
    size <integer_cst 0x7fc34ce71dc8 type <integer_type 0x7fc34ce7c0a8
bitsizetype> constant 32>
    unit size <integer_cst 0x7fc34ce71de0 type <integer_type 0x7fc34ce7c000
sizetype> constant 4>
    align 32 symtab 0 alias set -1 canonical type 0x7fc34ce899d8
    fields <field_decl 0x7fc34ce87130 __ap
        type <pointer_type 0x7fc34ce84000 type <void_type 0x7fc34ce7cf18 void>
            public unsigned SI size <integer_cst 0x7fc34ce71dc8 32> unit size
<integer_cst 0x7fc34ce71de0 4>
            align 32 symtab 0 alias set 3 canonical type 0x7fc34ce84000
            pointer_to_this <pointer_type 0x7fc34ce8a348>>
        unsigned SI file <built-in> line 0 col 0 size <integer_cst
0x7fc34ce71dc8 32> unit size <integer_cst 0x7fc34ce71de0 4>
        align 32 offset_align 64
        offset <integer_cst 0x7fc34ce71df8 constant 0>
        bit offset <integer_cst 0x7fc34ce71e58 constant 0> context <record_type
0x7fc34ce899d8 __va_list>> context <translation_unit_decl 0x7fc34df310f0
D.4035>
    pointer_to_this <pointer_type 0x7fc34ccaa2a0> chain <type_decl
0x7fc34ce87da8 __va_list>>

TREE_TYPE of PARAMETER of function BUILT_IN_VSNPRINTF_CHK:
 <reference_type 0x7fc34ce89c78
    type <record_type 0x7fc34ce899d8 __va_list SI
        size <integer_cst 0x7fc34ce71dc8 constant 32>
        unit size <integer_cst 0x7fc34ce71de0 constant 4>
        align 32 symtab 0 alias set 7 canonical type 0x7fc34ce899d8
        fields <field_decl 0x7fc34ce87130 __ap type <pointer_type
0x7fc34ce84000>
            unsigned SI file <built-in> line 0 col 0 size <integer_cst
0x7fc34ce71dc8 32> unit size <integer_cst 0x7fc34ce71de0 4>
            align 32 offset_align 64
            offset <integer_cst 0x7fc34ce71df8 constant 0>
            bit offset <integer_cst 0x7fc34ce71e58 constant 0> context
<record_type 0x7fc34ce899d8 __va_list>>
        pointer_to_this <pointer_type 0x7fc34ccc4888> reference_to_this
<reference_type 0x7fc34ccaa0a8> chain <type_decl 0x7fc34ce87098 __va_list>>
    unsigned SI size <integer_cst 0x7fc34ce71dc8 32> unit size <integer_cst
0x7fc34ce71de0 4>
    align 32 symtab 0 alias set -1 canonical type 0x7fc34ce89c78>


The root cause lies in gcc/lto/lto-lang.c:lto_init, there is below code
snippet:

  if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
    {
      tree x = build_pointer_type (TREE_TYPE (va_list_type_node));
      lto_define_builtins (x, x);
    }
  else
    {
      lto_define_builtins (va_list_type_node,
               build_reference_type (va_list_type_node));
    }

While prototype of lto_define_builtins is like below.
static void
lto_define_builtins (tree va_list_ref_type_node ATTRIBUTE_UNUSED,
             tree va_list_arg_type_node ATTRIBUTE_UNUSED);

Apparently, the arguments passed to lto_define_builtins are mis-matched.  In
fact, I think it should be consistent with function calls to c_define_builtins
in c front-end.

I think above analysis also explains why it happens only with lto.

I will send a patch fixing this soon.

Thanks,
bin

[Bug tree-optimization/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

--- Comment #4 from rguenther at suse dot de <rguenther at suse dot de> ---
On Thu, 7 Aug 2014, amker.cheng at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032
> 
> --- Comment #3 from bin.cheng <amker.cheng at gmail dot com> ---
> I did some investigation and think it's a latent bug of lto which reveaded by
> r213585.
> 
> Before the revision, pass_fold_builtins::execute calls gimple_fold_builtins
> directly to fold __builtin___vsnprintf_chk (_26, _25, 0, 4294967295, "%d - %c",
> ap);.  It works fine by simplifying the builtin into __builtin_vsnprintf (_26,
> _25, "%d - %c", ap);.
> 
> After the revision, it calls to
> fold_stmt->gimple_fold_call->gimple_fold_builtin to do the job.  But before
> that, it calls gimple_call_builtin_p to verify that it IS a valid builtin call,
> which in turn calls gimple_builtin_call_types_compatible_p to check that types
> between parameter and argument match each other.  Well, the check fails on the
> last parameter/argument, as dumped below:
> 
> TREE_TYPE of ARGUMENT:
>  <record_type 0x7fc34cc9fc78 va_list SI
>     size <integer_cst 0x7fc34ce71dc8 type <integer_type 0x7fc34ce7c0a8
> bitsizetype> constant 32>
>     unit size <integer_cst 0x7fc34ce71de0 type <integer_type 0x7fc34ce7c000
> sizetype> constant 4>
>     align 32 symtab 0 alias set -1 canonical type 0x7fc34ce899d8
>     fields <field_decl 0x7fc34ce87130 __ap
>         type <pointer_type 0x7fc34ce84000 type <void_type 0x7fc34ce7cf18 void>
>             public unsigned SI size <integer_cst 0x7fc34ce71dc8 32> unit size
> <integer_cst 0x7fc34ce71de0 4>
>             align 32 symtab 0 alias set 3 canonical type 0x7fc34ce84000
>             pointer_to_this <pointer_type 0x7fc34ce8a348>>
>         unsigned SI file <built-in> line 0 col 0 size <integer_cst
> 0x7fc34ce71dc8 32> unit size <integer_cst 0x7fc34ce71de0 4>
>         align 32 offset_align 64
>         offset <integer_cst 0x7fc34ce71df8 constant 0>
>         bit offset <integer_cst 0x7fc34ce71e58 constant 0> context <record_type
> 0x7fc34ce899d8 __va_list>> context <translation_unit_decl 0x7fc34df310f0
> D.4035>
>     pointer_to_this <pointer_type 0x7fc34ccaa2a0> chain <type_decl
> 0x7fc34ce87da8 __va_list>>
> 
> TREE_TYPE of PARAMETER of function BUILT_IN_VSNPRINTF_CHK:
>  <reference_type 0x7fc34ce89c78
>     type <record_type 0x7fc34ce899d8 __va_list SI
>         size <integer_cst 0x7fc34ce71dc8 constant 32>
>         unit size <integer_cst 0x7fc34ce71de0 constant 4>
>         align 32 symtab 0 alias set 7 canonical type 0x7fc34ce899d8
>         fields <field_decl 0x7fc34ce87130 __ap type <pointer_type
> 0x7fc34ce84000>
>             unsigned SI file <built-in> line 0 col 0 size <integer_cst
> 0x7fc34ce71dc8 32> unit size <integer_cst 0x7fc34ce71de0 4>
>             align 32 offset_align 64
>             offset <integer_cst 0x7fc34ce71df8 constant 0>
>             bit offset <integer_cst 0x7fc34ce71e58 constant 0> context
> <record_type 0x7fc34ce899d8 __va_list>>
>         pointer_to_this <pointer_type 0x7fc34ccc4888> reference_to_this
> <reference_type 0x7fc34ccaa0a8> chain <type_decl 0x7fc34ce87098 __va_list>>
>     unsigned SI size <integer_cst 0x7fc34ce71dc8 32> unit size <integer_cst
> 0x7fc34ce71de0 4>
>     align 32 symtab 0 alias set -1 canonical type 0x7fc34ce89c78>
> 
> 
> The root cause lies in gcc/lto/lto-lang.c:lto_init, there is below code
> snippet:
> 
>   if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
>     {
>       tree x = build_pointer_type (TREE_TYPE (va_list_type_node));
>       lto_define_builtins (x, x);
>     }
>   else
>     {
>       lto_define_builtins (va_list_type_node,
>                build_reference_type (va_list_type_node));
>     }
> 
> While prototype of lto_define_builtins is like below.
> static void
> lto_define_builtins (tree va_list_ref_type_node ATTRIBUTE_UNUSED,
>              tree va_list_arg_type_node ATTRIBUTE_UNUSED);
> 
> Apparently, the arguments passed to lto_define_builtins are mis-matched.  In
> fact, I think it should be consistent with function calls to c_define_builtins
> in c front-end.
> 
> I think above analysis also explains why it happens only with lto.
> 
> I will send a patch fixing this soon.

Thanks for the detective work!  IMHO this fix is worth backporting
to at least 4.9.

Richard.

[Bug lto/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

--- Comment #5 from amker at gcc dot gnu.org ---
Author: amker
Date: Fri Aug  8 10:21:12 2014
New Revision: 213755

URL: https://gcc.gnu.org/viewcvs?rev=213755&root=gcc&view=rev
Log:

    PR lto/62032
    * lto/lto-lang.c (lto_init): Switch mis-matched arguments.


Modified:
    trunk/gcc/lto/ChangeLog
    trunk/gcc/lto/lto-lang.c

[Bug lto/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

amker at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|4.9.1                       |
      Known to fail|4.10.0                      |

--- Comment #7 from amker at gcc dot gnu.org ---
Should be fixed now.

[Bug lto/62032] FAIL: vsnprintf-chk.c execution, -O2 -flto -fno-use-linker-plugin -flto-partition=none

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62032

amker at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #8 from amker at gcc dot gnu.org ---
Closing.