Re: [GOOGLE] Fix dynamic instrumentation patching for cold sections

[Xinliang David Li <davidxl at google dot com>]

ok.

David

On Tue, Sep 23, 2014 at 10:27 AM, Teresa Johnson <tejohnson@google.com> wrote:
> This patch fixes the support for patching for instrumentation so that it
> works with function splitting, by using the correct helper method for locating
> the current section.
>
> Added a couple tests cloned from existing function splitting tests that
> I confirmed expose the problem.
>
> Passes regression tests. Ok for google branches?
>
> Thanks,
> Teresa
>
> 2014-09-23  Teresa Johnson  <tejohnson@google.com>
>
>         Google ref b/17608598.
>         * config/i386/i386.c (ix86_output_function_nops_prologue_epilogue):
>         Ensure we switch to correct section.
>         * testsuite/gcc.dg/tree-prof/cold_partition_patch.c: New test.
>         * testsuite/g++.dg/tree-prof/partition_patch.C: Ditto.
>
> Index: config/i386/i386.c
> ===================================================================
> --- config/i386/i386.c  (revision 215515)
> +++ config/i386/i386.c  (working copy)
> @@ -11946,7 +11946,7 @@ ix86_output_function_nops_prologue_epilogue (FILE
>    fprintf (file, "\n");
>
>    /* Switching back to text section.  */
> -  switch_to_section (function_section (current_function_decl));
> +  switch_to_section (current_function_section ());
>    return true;
>  }
>
> Index: testsuite/gcc.dg/tree-prof/cold_partition_patch.c
> ===================================================================
> --- testsuite/gcc.dg/tree-prof/cold_partition_patch.c   (revision 0)
> +++ testsuite/gcc.dg/tree-prof/cold_partition_patch.c   (revision 0)
> @@ -0,0 +1,38 @@
> +/* Check if patching works with function splitting. */
> +/* { dg-do compile { target x86_64-*-* } } */
> +/* { dg-require-effective-target freorder } */
> +/* { dg-options "-O2 -freorder-blocks-and-partition -save-temps
> -mpatch-functions-for-instrumentation -fno-optimize-sibling-calls " }
> */
> +
> +#define SIZE 10000
> +
> +const char *sarr[SIZE];
> +const char *buf_hot;
> +const char *buf_cold;
> +
> +__attribute__((noinline))
> +void
> +foo (int path)
> +{
> +  int i;
> +  if (path)
> +    {
> +      for (i = 0; i < SIZE; i++)
> +       sarr[i] = buf_hot;
> +    }
> +  else
> +    {
> +      for (i = 0; i < SIZE; i++)
> +       sarr[i] = buf_cold;
> +    }
> +}
> +
> +int
> +main (int argc, char *argv[])
> +{
> +  buf_hot =  "hello";
> +  buf_cold = "world";
> +  foo (argc);
> +  return 0;
> +}
> +
> +/* { dg-final-use { cleanup-saved-temps } } */
> Index: testsuite/g++.dg/tree-prof/partition_patch.C
> ===================================================================
> --- testsuite/g++.dg/tree-prof/partition_patch.C        (revision 0)
> +++ testsuite/g++.dg/tree-prof/partition_patch.C        (revision 0)
> @@ -0,0 +1,19 @@
> +// Check if patching works with function splitting.
> +// { dg-do compile { target x86_64-*-* } }
> +// { dg-require-effective-target freorder }
> +// { dg-options "-O2 -fnon-call-exceptions
> -freorder-blocks-and-partition -mpatch-functions-for-instrumentation
> -fno-optimize-sibling-calls " }
> +
> +int k;
> +
> +int
> +main ()
> +{
> +  try
> +  {
> +    if (k)
> +      throw 6;
> +  }
> +  catch (...)
> +  {
> +  }
> +}
>
>
> --
> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413