Re: [PATCH] PR target/68986: [5/6 Regression] internal compiler error: Segmentation fault

[Uros Bizjak <ubizjak at gmail dot com>]

On Tue, Jan 26, 2016 at 1:58 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Stack alignment adjustment for __tls_get_addr should be done in
> ix86_update_stack_boundary, not ix86_compute_frame_layout.  Also
> there is no need to over-align stack for __tls_get_addr and function
> with __tls_get_addr call isn't a leaf function.
>
> Tested on x86-64 with -m32 on testsuite.  OK for trunk?

OK, but please write the second part without extra parenthesis as:

  unsigned int stack_realign
    = (incoming_stack_boundary
       < (crtl->is_leaf && !ix86_current_function_calls_tls_descriptor
      ? crtl->max_used_stack_slot_alignment
      : crtl->stack_alignment_needed));

Thanks,
Uros.

>
> Thanks.
>
> H.J.
> ---
> gcc/
>
>         PR target/68986
>         * config/i386/i386.c (ix86_compute_frame_layout): Move stack
>         alignment adjustment to ...
>         (ix86_update_stack_boundary): Here.  Don't over-align stack for
>         __tls_get_addr.
>         (ix86_finalize_stack_realign_flags): Use stack_alignment_needed
>         if __tls_get_addr is called.
>
> gcc/testsuite/
>
>         PR target/68986
>         * gcc.target/i386/pr68986-1.c: New test.
>         * gcc.target/i386/pr68986-2.c: Likewise.
>         * gcc.target/i386/pr68986-3.c: Likewise.
> ---
>  gcc/config/i386/i386.c                    | 24 +++++++++++-------------
>  gcc/testsuite/gcc.target/i386/pr68986-1.c | 11 +++++++++++
>  gcc/testsuite/gcc.target/i386/pr68986-2.c | 13 +++++++++++++
>  gcc/testsuite/gcc.target/i386/pr68986-3.c | 13 +++++++++++++
>  4 files changed, 48 insertions(+), 13 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr68986-1.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr68986-2.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr68986-3.c
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 34b57a4..9c27ea9 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -11360,18 +11360,6 @@ ix86_compute_frame_layout (struct ix86_frame *frame)
>        crtl->preferred_stack_boundary = 128;
>        crtl->stack_alignment_needed = 128;
>      }
> -  /* preferred_stack_boundary is never updated for call
> -     expanded from tls descriptor. Update it here. We don't update it in
> -     expand stage because according to the comments before
> -     ix86_current_function_calls_tls_descriptor, tls calls may be optimized
> -     away.  */
> -  else if (ix86_current_function_calls_tls_descriptor
> -          && crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
> -    {
> -      crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
> -      if (crtl->stack_alignment_needed < PREFERRED_STACK_BOUNDARY)
> -       crtl->stack_alignment_needed = PREFERRED_STACK_BOUNDARY;
> -    }
>
>    stack_alignment_needed = crtl->stack_alignment_needed / BITS_PER_UNIT;
>    preferred_alignment = crtl->preferred_stack_boundary / BITS_PER_UNIT;
> @@ -12043,6 +12031,15 @@ ix86_update_stack_boundary (void)
>        && cfun->stdarg
>        && crtl->stack_alignment_estimated < 128)
>      crtl->stack_alignment_estimated = 128;
> +
> +  /* __tls_get_addr needs to be called with 16-byte aligned stack.  */
> +  if (ix86_tls_descriptor_calls_expanded_in_cfun
> +      && crtl->preferred_stack_boundary < 128)
> +    {
> +      crtl->preferred_stack_boundary = 128;
> +      if (crtl->stack_alignment_needed < 128)
> +       crtl->stack_alignment_needed = 128;
> +    }
>  }
>
>  /* Handle the TARGET_GET_DRAP_RTX hook.  Return NULL if no DRAP is
> @@ -12506,7 +12503,8 @@ ix86_finalize_stack_realign_flags (void)
>      = (crtl->parm_stack_boundary > ix86_incoming_stack_boundary
>         ? crtl->parm_stack_boundary : ix86_incoming_stack_boundary);
>    unsigned int stack_realign = (incoming_stack_boundary
> -                               < (crtl->is_leaf
> +                               < ((crtl->is_leaf
> +                                   && !ix86_current_function_calls_tls_descriptor)
>                                    ? crtl->max_used_stack_slot_alignment
>                                    : crtl->stack_alignment_needed));
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr68986-1.c b/gcc/testsuite/gcc.target/i386/pr68986-1.c
> new file mode 100644
> index 0000000..998f34f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68986-1.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target tls_native } */
> +/* { dg-require-effective-target fpic } */
> +/* { dg-options "-fPIC -mno-accumulate-outgoing-args -mpreferred-stack-boundary=5 -mincoming-stack-boundary=4" } */
> +
> +extern __thread int msgdata;
> +int
> +foo ()
> +{
> +  return msgdata;
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr68986-2.c b/gcc/testsuite/gcc.target/i386/pr68986-2.c
> new file mode 100644
> index 0000000..23f9a52
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68986-2.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile { target ia32 } } */
> +/* { dg-require-effective-target tls_native } */
> +/* { dg-require-effective-target fpic } */
> +/* { dg-options "-fPIC -mno-accumulate-outgoing-args -mpreferred-stack-boundary=2 -m32" } */
> +
> +extern __thread int msgdata;
> +int
> +foo ()
> +{
> +  return msgdata;
> +}
> +
> +/* { dg-final { scan-assembler "andl\[\\t \]*\\$-16,\[\\t \]*%esp" } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr68986-3.c b/gcc/testsuite/gcc.target/i386/pr68986-3.c
> new file mode 100644
> index 0000000..5744cf2
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr68986-3.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target tls_native } */
> +/* { dg-require-effective-target fpic } */
> +/* { dg-options "-fPIC -mno-sse -mpreferred-stack-boundary=3 -mincoming-stack-boundary=3" } */
> +
> +extern __thread int msgdata;
> +int
> +foo ()
> +{
> +  return msgdata;
> +}
> +
> +/* { dg-final { scan-assembler "and\[lq\]\[\\t \]*\\$-16,\[\\t \]*%\[re\]?sp" } } */
> --
> 2.5.0
>