On Thu, Jul 21, 2022 at 11:53 AM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> We can't always use the PLT entry as the function address for local IFUNC
> functions. When the PIC register is needed for PLT call, indirect call
> via the PLT entry will fail since the PIC register may not be set up
> properly for indirect call. Add ix86_ifunc_ref_local_ok to return false
> when the PLT entry can't be used as local IFUNC function pointers.
>
> gcc/
>
> PR target/83782
> * config/i386/i386.cc (ix86_ifunc_ref_local_ok): New.
> (TARGET_IFUNC_REF_LOCAL_OK): Use it.
>
> gcc/testsuite/
>
> PR target/83782
> * gcc.target/i386/pr83782-1.c: Require non-ia32.
> * gcc.target/i386/pr83782-2.c: Likewise.
> * gcc.target/i386/pr83782-3.c: New test.
> ---
> gcc/config/i386/i386.cc | 15 ++++++++++-
> gcc/testsuite/gcc.target/i386/pr83782-1.c | 8 +++---
> gcc/testsuite/gcc.target/i386/pr83782-2.c | 4 +--
> gcc/testsuite/gcc.target/i386/pr83782-3.c | 32 +++++++++++++++++++++++
> 4 files changed, 50 insertions(+), 9 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr83782-3.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index e03f86d4a23..5e30dc884bf 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -16070,6 +16070,19 @@ ix86_call_use_plt_p (rtx call_op)
> return true;
> }
>
> +/* Implement TARGET_IFUNC_REF_LOCAL_OK. If this hook returns true,
> + the PLT entry will be used as the function address for local IFUNC
> + functions. When the PIC register is needed for PLT call, indirect
> + call via the PLT entry will fail since the PIC register may not be
> + set up properly for indirect call. In this case, we should return
> + false. */
> +
> +static bool
> +ix86_ifunc_ref_local_ok (void)
> +{
> + return !flag_pic || (TARGET_64BIT && ix86_cmodel != CM_LARGE_PIC);
> +}
> +
> /* Return true if the function being called was marked with attribute
> "noplt" or using -fno-plt and we are compiling for non-PIC. We need
> to handle the non-PIC case in the backend because there is no easy
> @@ -24953,7 +24966,7 @@ ix86_libgcc_floating_mode_supported_p
> ix86_get_multilib_abi_name
>
> #undef TARGET_IFUNC_REF_LOCAL_OK
> -#define TARGET_IFUNC_REF_LOCAL_OK hook_bool_void_true
> +#define TARGET_IFUNC_REF_LOCAL_OK ix86_ifunc_ref_local_ok
>
> #if !TARGET_MACHO && !TARGET_DLLIMPORT_DECL_ATTRIBUTES
> # undef TARGET_ASM_RELOC_RW_MASK
> diff --git a/gcc/testsuite/gcc.target/i386/pr83782-1.c
> b/gcc/testsuite/gcc.target/i386/pr83782-1.c
> index ce97b12e65d..85674346aec 100644
> --- a/gcc/testsuite/gcc.target/i386/pr83782-1.c
> +++ b/gcc/testsuite/gcc.target/i386/pr83782-1.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile } */
> +/* { dg-do compile { target { ! ia32 } } } */
> /* { dg-require-ifunc "" } */
> /* { dg-options "-O2 -fpic" } */
>
> @@ -20,7 +20,5 @@ bar(void)
> return foo;
> }
>
> -/* { dg-final { scan-assembler {leal[ \t]foo@GOTOFF\(%[^,]*\),[ \t]%eax} {
> target ia32 } } } */
> -/* { dg-final { scan-assembler {lea(?:l|q)[ \t]foo\(%rip\),[ \t]%(?:e|r)ax}
> { target { ! ia32 } } } } */
> -/* { dg-final { scan-assembler-not "foo@GOT\\\(" { target ia32 } } } */
> -/* { dg-final { scan-assembler-not "foo@GOTPCREL\\\(" { target { ! ia32 } }
> } } */
> +/* { dg-final { scan-assembler {lea(?:l|q)[ \t]foo\(%rip\),[ \t]%(?:e|r)ax}
> } } */
> +/* { dg-final { scan-assembler-not "foo@GOTPCREL\\\(" } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr83782-2.c
> b/gcc/testsuite/gcc.target/i386/pr83782-2.c
> index e25d258bbda..a654ded771f 100644
> --- a/gcc/testsuite/gcc.target/i386/pr83782-2.c
> +++ b/gcc/testsuite/gcc.target/i386/pr83782-2.c
> @@ -1,4 +1,4 @@
> -/* { dg-do compile } */
> +/* { dg-do compile { target { ! ia32 } } } */
> /* { dg-require-ifunc "" } */
> /* { dg-options "-O2 -fpic" } */
>
> @@ -20,7 +20,5 @@ bar(void)
> return foo;
> }
>
> -/* { dg-final { scan-assembler {leal[ \t]foo@GOTOFF\(%[^,]*\),[ \t]%eax} {
> target ia32 } } } */
> /* { dg-final { scan-assembler {lea(?:l|q)[ \t]foo\(%rip\),[ \t]%(?:e|r)ax}
> { target { ! ia32 } } } } */
> -/* { dg-final { scan-assembler-not "foo@GOT\\\(" { target ia32 } } } */
> /* { dg-final { scan-assembler-not "foo@GOTPCREL\\\(" { target { ! ia32 } }
> } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr83782-3.c
> b/gcc/testsuite/gcc.target/i386/pr83782-3.c
> new file mode 100644
> index 00000000000..1536481cb79
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr83782-3.c
> @@ -0,0 +1,32 @@
> +/* { dg-do run } */
> +/* { dg-require-ifunc "" } */
> +/* { dg-require-effective-target pie } */
> +/* { dg-options "-fpie -pie" } */
> +
> +#include <stdio.h>
> +
> +static int __attribute__((noinline))
> +implementation (void)
> +{
> + printf ("'ere I am JH\n");
> + return 0;
> +}
> +
> +static __typeof__ (implementation) *resolver (void)
> +{
> + return (void *)implementation;
> +}
> +
> +extern int magic (void) __attribute__ ((ifunc ("resolver")));
> +
> +__attribute__ ((weak))
> +int
> +call_magic (int (*ptr) (void))
> +{
> + return ptr ();
> +}
> +
> +int main ()
> +{
> + return call_magic (magic);
> +}
> --
> 2.36.1
>
PING.
--
H.J.
