PING^1 [PATCH] i386: Disallow sibcall when calling ifunc functions with PIC register

["H.J. Lu" <hjl.tools@gmail.com>]

On Tue, Jun 14, 2022 at 12:25 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Disallow siball when calling ifunc functions with PIC register so that
> PIC register can be restored.
>
> gcc/
>
>         PR target/105960
>         * config/i386/i386.cc (ix86_function_ok_for_sibcall): Return
>         false if PIC register is used when calling ifunc functions.
>
> gcc/testsuite/
>
>         PR target/105960
>         * gcc.target/i386/pr105960.c: New test.
> ---
>  gcc/config/i386/i386.cc                  |  9 +++++++++
>  gcc/testsuite/gcc.target/i386/pr105960.c | 19 +++++++++++++++++++
>  2 files changed, 28 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr105960.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index 3d189e124e4..1ca7836e11e 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -1015,6 +1015,15 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
>         }
>      }
>
> +  if (decl && ix86_use_pseudo_pic_reg ())
> +    {
> +      /* When PIC register is used, it must be restored after ifunc
> +        function returns.  */
> +       cgraph_node *node = cgraph_node::get (decl);
> +       if (node && node->ifunc_resolver)
> +        return false;
> +    }
> +
>    /* Otherwise okay.  That also includes certain types of indirect calls.  */
>    return true;
>  }
> diff --git a/gcc/testsuite/gcc.target/i386/pr105960.c b/gcc/testsuite/gcc.target/i386/pr105960.c
> new file mode 100644
> index 00000000000..db137a1642d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr105960.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-require-ifunc "" } */
> +/* { dg-options "-O2 -fpic" } */
> +
> +__attribute__((target_clones("default","fma")))
> +static inline double
> +expfull_ref(double x)
> +{
> +  return __builtin_pow(x, 0.1234);
> +}
> +
> +double
> +exp_ref(double x)
> +{
> +  return expfull_ref(x);
> +}
> +
> +/* { dg-final { scan-assembler "jmp\[ \t\]*expfull_ref@PLT" { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*expfull_ref@PLT" { target ia32 } } } */
> --
> 2.36.1
>

PING.

-- 
H.J.