[glibc] LoongArch: Simplify the autoconf check for static PIE

[Yinyu Cai <caiyinyu@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e757412c3e8a59cd93230414800250b38aeddf6c

commit e757412c3e8a59cd93230414800250b38aeddf6c
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Sun Aug 27 00:36:49 2023 +0800

    LoongArch: Simplify the autoconf check for static PIE
    
    We are strictly requiring GAS >= 2.41 now, so we don't need to check
    assembler capability anymore.
    
    Signed-off-by: Xi Ruoyao <xry111@xry111.site>

Diff:
---
 sysdeps/loongarch/configure    | 36 +++++++-----------------------------
 sysdeps/loongarch/configure.ac | 30 +++++++++---------------------
 2 files changed, 16 insertions(+), 50 deletions(-)

diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure
index 395ddc92ca..30b60d1983 100644
--- a/sysdeps/loongarch/configure
+++ b/sysdeps/loongarch/configure
@@ -4,21 +4,19 @@
 printf "%s\n" "#define HIDDEN_VAR_NEEDS_DYNAMIC_RELOC 1" >>confdefs.h
 
 
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if the toolchain is sufficient to build static PIE on LoongArch" >&5
-printf %s "checking if the toolchain is sufficient to build static PIE on LoongArch... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking if ${CC-cc} is sufficient to build static PIE on LoongArch" >&5
+printf %s "checking if ${CC-cc} is sufficient to build static PIE on LoongArch... " >&6; }
 if test ${libc_cv_static_pie_on_loongarch+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
 
-  cat > conftest1.S <<\EOF
+  cat > conftest.S <<\EOF
 .global _start
 .type _start, @function
 _start:
   li.w $a7, 93
-  /* This ensures the assembler supports explicit reloc.  */
-  pcalau12i $a0, %pc_hi20(x)
-  ld.w $a0, $a0, %pc_lo12(x)
+  li.w $a0, 0
   syscall 0
 
 .data
@@ -27,41 +25,21 @@ x:
   /* This should produce an R_LARCH_RELATIVE in the static PIE.  */
   .dword _start
 EOF
-  cat > conftest2.S <<\EOF
-.global f
-.type f, @function
-f:
-  /* The linker should be able to handle this and produce a PLT entry.  */
-  la.pcrel $t0, $t0, external_func
-  jirl $zero, $t0, 0
-EOF
 
   libc_cv_static_pie_on_loongarch=no
-  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; } \
-     && { ac_try='LC_ALL=C $READELF -Wr conftest1 | grep -q R_LARCH_RELATIVE'
-  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; }; } \
-     && ! { ac_try='LC_ALL=C $READELF -Wl conftest1 | grep -q INTERP'
+  if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.S'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; } \
-     && { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -shared -nostdlib -fPIC -o conftest2.so conftest2.S'
+     && { ac_try='LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
   printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; } \
-     && { ac_try='LC_ALL=C $READELF -Wr conftest2.so | grep -q 'R_LARCH_JUMP_SLOT.*external_func''
+     && ! { ac_try='LC_ALL=C $READELF -Wl conftest | grep -q INTERP'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac
index 989287c6d2..28a8ae5486 100644
--- a/sysdeps/loongarch/configure.ac
+++ b/sysdeps/loongarch/configure.ac
@@ -8,19 +8,17 @@ AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)
 dnl Test if the toolchain is new enough for static PIE.
 dnl We need a GAS supporting explicit reloc (older GAS produces stack-based
 dnl reloc and triggers an internal error in the linker).  And, we need GCC to
-dnl pass the correct linker flags for static PIE.  GCC >= 13 and GAS >= 2.40
-dnl satisfy the requirement, but a distro may backport static PIE support into
-dnl earlier GCC or Binutils releases as well.
-AC_CACHE_CHECK([if the toolchain is sufficient to build static PIE on LoongArch],
+dnl pass the correct linker flags for static PIE.  We strictly require GAS >=
+dnl 2.41 so we don't need to check the assembler capability, but we need to
+dnl check if GCC is doing the correct thing.
+AC_CACHE_CHECK([if ${CC-cc} is sufficient to build static PIE on LoongArch],
 libc_cv_static_pie_on_loongarch, [
-  cat > conftest1.S <<\EOF
+  cat > conftest.S <<\EOF
 .global _start
 .type _start, @function
 _start:
   li.w $a7, 93
-  /* This ensures the assembler supports explicit reloc.  */
-  pcalau12i $a0, %pc_hi20(x)
-  ld.w $a0, $a0, %pc_lo12(x)
+  li.w $a0, 0
   syscall 0
 
 .data
@@ -29,21 +27,11 @@ x:
   /* This should produce an R_LARCH_RELATIVE in the static PIE.  */
   .dword _start
 EOF
-  cat > conftest2.S <<\EOF
-.global f
-.type f, @function
-f:
-  /* The linker should be able to handle this and produce a PLT entry.  */
-  la.pcrel $t0, $t0, external_func
-  jirl $zero, $t0, 0
-EOF
 
   libc_cv_static_pie_on_loongarch=no
-  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S]) \
-     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest1 | grep -q R_LARCH_RELATIVE]) \
-     && ! AC_TRY_COMMAND([LC_ALL=C $READELF -Wl conftest1 | grep -q INTERP]) \
-     && AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -shared -nostdlib -fPIC -o conftest2.so conftest2.S]) \
-     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest2.so | grep -q 'R_LARCH_JUMP_SLOT.*external_func'])
+  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest conftest.S]) \
+     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest | grep -q R_LARCH_RELATIVE]) \
+     && ! AC_TRY_COMMAND([LC_ALL=C $READELF -Wl conftest | grep -q INTERP])
   then
     libc_cv_static_pie_on_loongarch=yes
   fi