[PATCH] libiberty: Fix build with GCC < 7

[PATCH] libiberty: Fix build with GCC < 7

[Jakub Jelinek]

Hi!

Tobias reported on IRC that the linker fails to build with GCC 4.8.5.
In configure I've tried to use everything actually used in the sha1.c
x86 hw implementation, but unfortunately I forgot about implicit function
declarations.  GCC before 7 did have <cpuid.h> header and bit_SHA define
and __get_cpuid function defined inline, but it didn't define
__get_cpuid_count, which compiled fine (and the configure test is
intentionally compile time only) due to implicit function declaration,
but then failed to link when linking the linker, because
__get_cpuid_count wasn't defined anywhere.

The following patch fixes that by using what autoconf uses in AC_CHECK_DECL
to make sure the functions are declared.

Bootstrapped/regtested in GCC on x86_64-linux and i686-linux with GCC 12 as
system compiler (HAVE_X86_SHA1_HW_SUPPORT is defined there) and tested by
Tobias with GCC 4.8.5 (it isn't defined there anymore).

Ok for trunk (both gcc and binutils)?

2023-12-05  Jakub Jelinek  <jakub@redhat.com>

	* configure.ac (HAVE_X86_SHA1_HW_SUPPORT): Verify __get_cpuid and
	__get_cpuid_count are not implicitly declared.
	* configure: Regenerated.

--- libiberty/configure.ac.jj	2023-12-01 08:10:44.877293904 +0100
+++ libiberty/configure.ac	2023-12-05 16:09:49.506323449 +0100
@@ -771,6 +771,8 @@ void foo (__m128i *buf, unsigned int e,
 int bar (void)
 {
   unsigned int eax, ebx, ecx, edx;
+  (void) __get_cpuid;
+  (void) __get_cpuid_count;
   if (__get_cpuid_count (7, 0, &eax, &ebx, &ecx, &edx)
       && (ebx & bit_SHA) != 0
       && __get_cpuid (1, &eax, &ebx, &ecx, &edx)
--- libiberty/configure.jj	2023-12-01 08:10:44.876293919 +0100
+++ libiberty/configure	2023-12-05 16:10:06.415083621 +0100
@@ -7667,6 +7667,8 @@ void foo (__m128i *buf, unsigned int e,
 int bar (void)
 {
   unsigned int eax, ebx, ecx, edx;
+  (void) __get_cpuid;
+  (void) __get_cpuid_count;
   if (__get_cpuid_count (7, 0, &eax, &ebx, &ecx, &edx)
       && (ebx & bit_SHA) != 0
       && __get_cpuid (1, &eax, &ebx, &ecx, &edx)

	Jakub

Re: [PATCH] libiberty: Fix build with GCC < 7

[Ian Lance Taylor]

On Tue, Dec 5, 2023 at 2:06 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> Ok for trunk (both gcc and binutils)?
>
> 2023-12-05  Jakub Jelinek  <jakub@redhat.com>
>
>         * configure.ac (HAVE_X86_SHA1_HW_SUPPORT): Verify __get_cpuid and
>         __get_cpuid_count are not implicitly declared.
>         * configure: Regenerated.

This is fine.  Thanks.

Ian