[PATCH 58/59] configure: remove overly restrictive check for clang

[Collin Funk]

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:

> The clang support is still experimental and not all testcase build
> or run correctly.  Only clang 18 and onwards is supported and only
> for x86_64-linux-gnu and aarch64-linux-gnu.
> ---
>  configure    | 13 +++++--------
>  configure.ac |  4 ++--
>  2 files changed, 7 insertions(+), 10 deletions(-)

s/testcase/testcases/

> diff --git a/configure b/configure
> index c8ed16bd79d..083122a5ae0 100755
> --- a/configure
> +++ b/configure
> @@ -5800,7 +5800,7 @@ int
>  main (void)
>  {
>  
> -#if !defined __GNUC__ || __GNUC__ < 12 || (__GNUC__ == 12 && __GNUC_MINOR__ < 1)
> +#if (!defined __GNUC__ || __GNUC__ < 12 || (__GNUC__ == 12 && __GNUC_MINOR__ < 1)) && (!defined __clang__ || __clang_major__ < 18)
>  #error insufficient compiler
>  #endif
>    ;
> @@ -7515,8 +7515,7 @@ $conftest_code
>  EOF
>  
>  saved_CC="$CC"
> -saved_CFLAGS="$CFLAGS"
> -CC="$TEST_CC -Wno-unused-command-line-argument"
> +CC="$TEST_CC"
>  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for traditional tls support in testing" >&5
>  printf %s "checking for traditional tls support in testing... " >&6; }
>  if test ${libc_cv_test_mtls_traditional+y}
> @@ -7739,7 +7738,7 @@ else case e in #(
>  extern char *strstr (const char *, const char *) __asm ("my_strstr");
>  char *foo (const char *a, const char *b)
>  {
> -  return __builtin_strstr (a, b);
> +  return strstr (a, b);
>  }
>  EOF
>  if { ac_try='${CC-cc} -O3 -S conftest.c -o - | grep -F "my_strstr" > /dev/null'
> @@ -8110,8 +8109,7 @@ if test "$TEST_CC" = "$CC"; then
>  else
>  
>  saved_CC="$CC"
> -saved_CFLAGS="$CFLAGS"
> -CC="$TEST_CC -Wno-unused-command-line-argument"
> +CC="$TEST_CC"
>  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -Wfree-labels in testing" >&5
>  printf %s "checking for -Wfree-labels in testing... " >&6; }
>  if test ${libc_cv_test_cc_wfree_labels+y}
> @@ -8171,8 +8169,7 @@ if test "$TEST_CC" = "$CC"; then
>  else
>  
>  saved_CC="$CC"
> -saved_CFLAGS="$CFLAGS"
> -CC="$TEST_CC -Wno-unused-command-line-argument"
> +CC="$TEST_CC"
>  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for -Wmissing-parameter-name in testing" >&5
>  printf %s "checking for -Wmissing-parameter-name in testing... " >&6; }
>  if test ${libc_cv_test_cc_wmissing_parameter_name+y}
> diff --git a/configure.ac b/configure.ac
> index f5cbdd6bdb5..89659e905c7 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -585,7 +585,7 @@ AC_CHECK_PROG_VER(BISON, bison, --version,
>  # Require GCC 12.1 to build.
>  AC_CACHE_CHECK([if $CC is sufficient to build libc], libc_cv_compiler_ok, [
>  AC_PREPROC_IFELSE([AC_LANG_PROGRAM([[]], [[
> -#if !defined __GNUC__ || __GNUC__ < 12 || (__GNUC__ == 12 && __GNUC_MINOR__ < 1)
> +#if (!defined __GNUC__ || __GNUC__ < 12 || (__GNUC__ == 12 && __GNUC_MINOR__ < 1)) && (!defined __clang__ || __clang_major__ < 18)
>  #error insufficient compiler
>  #endif]])],
>  	       [libc_cv_compiler_ok=yes],
> @@ -1507,7 +1507,7 @@ cat > conftest.c <<\EOF
>  extern char *strstr (const char *, const char *) __asm ("my_strstr");
>  char *foo (const char *a, const char *b)
>  {
> -  return __builtin_strstr (a, b);
> +  return strstr (a, b);
>  }
>  EOF
>  dnl

This patch looks reasonable, so:

Reviewed-by: Collin Funk <collin.funk1@gmail.com>

However, I wonder if it is worth mentioning in INSTALL that Clang
support is experimental and requires version 18.

Or perhaps there is somewhere else that belongs? Anywhere more visible
configure.ac is probably fine with me.

Collin