[gcc r13-8350] LoongArch: Check whether binutils supports the relax function. If supported, explicit relocs are tur

[LuluCheng <chenglulu@gcc.gnu.org>]

https://gcc.gnu.org/g:504bb03e69bcd561421a1cbb3050c40b0f19bc22

commit r13-8350-g504bb03e69bcd561421a1cbb3050c40b0f19bc22
Author: Lulu Cheng <chenglulu@loongson.cn>
Date:   Fri Sep 15 10:22:49 2023 +0800

    LoongArch: Check whether binutils supports the relax function. If supported, explicit relocs are turned off by default.
    
    gcc/ChangeLog:
    
            * config.in: Regenerate.
            * config/loongarch/genopts/loongarch.opt.in: Add compilation option
            mrelax. And set the initial value of explicit-relocs according to the
            detection status.
            * config/loongarch/gnu-user.h: When compiling with -mno-relax, pass the
            --no-relax option to the linker.
            * config/loongarch/loongarch-opts.h (HAVE_AS_MRELAX_OPTION): Define macro.
            * config/loongarch/loongarch.opt: Regenerate.
            * configure: Regenerate.
            * configure.ac: Add detection of support for binutils relax function.
    
    (cherry picked from commit 9bab65a77049edcc7afc59532173206ee816e726)

Diff:
---
 gcc/config.in                                 |  6 ++++++
 gcc/config/loongarch/genopts/loongarch.opt.in |  7 +++++-
 gcc/config/loongarch/gnu-user.h               |  3 ++-
 gcc/config/loongarch/loongarch-opts.h         |  4 ++++
 gcc/config/loongarch/loongarch.opt            |  7 +++++-
 gcc/configure                                 | 31 +++++++++++++++++++++++++++
 gcc/configure.ac                              |  4 ++++
 7 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/gcc/config.in b/gcc/config.in
index ef35af16f2f1..36a74dd59748 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -636,6 +636,12 @@
 #endif
 
 
+/* Define if your assembler supports -mrelax option. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_AS_MRELAX_OPTION
+#endif
+
+
 /* Define if your assembler supports .mspabi_attribute. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_AS_MSPABI_ATTRIBUTE
diff --git a/gcc/config/loongarch/genopts/loongarch.opt.in b/gcc/config/loongarch/genopts/loongarch.opt.in
index 4b9b4ac273e9..e7c32e61a509 100644
--- a/gcc/config/loongarch/genopts/loongarch.opt.in
+++ b/gcc/config/loongarch/genopts/loongarch.opt.in
@@ -155,7 +155,7 @@ Target Joined RejectNegative UInteger Var(loongarch_max_inline_memcpy_size) Init
 -mmax-inline-memcpy-size=SIZE	Set the max size of memcpy to inline, default is 1024.
 
 mexplicit-relocs
-Target Var(TARGET_EXPLICIT_RELOCS) Init(HAVE_AS_EXPLICIT_RELOCS)
+Target Var(TARGET_EXPLICIT_RELOCS) Init(HAVE_AS_EXPLICIT_RELOCS & !HAVE_AS_MRELAX_OPTION)
 Use %reloc() assembly operators.
 
 ; The code model option names for -mcmodel.
@@ -188,3 +188,8 @@ Specify the code model.
 mdirect-extern-access
 Target Var(TARGET_DIRECT_EXTERN_ACCESS) Init(0)
 Avoid using the GOT to access external symbols.
+
+mrelax
+Target Var(loongarch_mrelax) Init(HAVE_AS_MRELAX_OPTION)
+Take advantage of linker relaxations to reduce the number of instructions
+required to materialize symbol addresses.
diff --git a/gcc/config/loongarch/gnu-user.h b/gcc/config/loongarch/gnu-user.h
index 5f1bd60ada3b..e9f4bcef1d47 100644
--- a/gcc/config/loongarch/gnu-user.h
+++ b/gcc/config/loongarch/gnu-user.h
@@ -48,7 +48,8 @@ along with GCC; see the file COPYING3.  If not see
   "%{!shared: %{static} " \
   "%{!static: %{!static-pie: %{rdynamic:-export-dynamic} " \
   "-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}} " \
-  "%{static-pie: -static -pie --no-dynamic-linker -z text}}"
+  "%{static-pie: -static -pie --no-dynamic-linker -z text}}" \
+  "%{mno-relax: --no-relax}"
 
 
 /* Similar to standard Linux, but adding -ffast-math support.  */
diff --git a/gcc/config/loongarch/loongarch-opts.h b/gcc/config/loongarch/loongarch-opts.h
index b1ff54426e42..7ea02f4978cc 100644
--- a/gcc/config/loongarch/loongarch-opts.h
+++ b/gcc/config/loongarch/loongarch-opts.h
@@ -92,4 +92,8 @@ loongarch_config_target (struct loongarch_target *target,
 #define HAVE_AS_EXPLICIT_RELOCS 0
 #endif
 
+#ifndef HAVE_AS_MRELAX_OPTION
+#define HAVE_AS_MRELAX_OPTION 0
+#endif
+
 #endif /* LOONGARCH_OPTS_H */
diff --git a/gcc/config/loongarch/loongarch.opt b/gcc/config/loongarch/loongarch.opt
index 68018ade73f0..e37ed9015de5 100644
--- a/gcc/config/loongarch/loongarch.opt
+++ b/gcc/config/loongarch/loongarch.opt
@@ -162,7 +162,7 @@ Target Joined RejectNegative UInteger Var(loongarch_max_inline_memcpy_size) Init
 -mmax-inline-memcpy-size=SIZE	Set the max size of memcpy to inline, default is 1024.
 
 mexplicit-relocs
-Target Var(TARGET_EXPLICIT_RELOCS) Init(HAVE_AS_EXPLICIT_RELOCS)
+Target Var(TARGET_EXPLICIT_RELOCS) Init(HAVE_AS_EXPLICIT_RELOCS & !HAVE_AS_MRELAX_OPTION)
 Use %reloc() assembly operators.
 
 ; The code model option names for -mcmodel.
@@ -195,3 +195,8 @@ Specify the code model.
 mdirect-extern-access
 Target Var(TARGET_DIRECT_EXTERN_ACCESS) Init(0)
 Avoid using the GOT to access external symbols.
+
+mrelax
+Target Var(loongarch_mrelax) Init(HAVE_AS_MRELAX_OPTION)
+Take advantage of linker relaxations to reduce the number of instructions
+required to materialize symbol addresses.
diff --git a/gcc/configure b/gcc/configure
index dec2eca1a453..760bea9d4a0a 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -29075,6 +29075,37 @@ if test $gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support = yes; then
 
 $as_echo "#define HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT 1" >>confdefs.h
 
+fi
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for -mrelax option" >&5
+$as_echo_n "checking assembler for -mrelax option... " >&6; }
+if ${gcc_cv_as_loongarch_relax+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_loongarch_relax=no
+  if test x$gcc_cv_as != x; then
+    $as_echo '.text' > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags -mrelax -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+	gcc_cv_as_loongarch_relax=yes
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_loongarch_relax" >&5
+$as_echo "$gcc_cv_as_loongarch_relax" >&6; }
+if test $gcc_cv_as_loongarch_relax = yes; then
+
+$as_echo "#define HAVE_AS_MRELAX_OPTION 1" >>confdefs.h
+
 fi
 
     ;;
diff --git a/gcc/configure.ac b/gcc/configure.ac
index c0d067ec2716..4f3c4ebb5a5f 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5366,6 +5366,10 @@ x:
        .cfi_endproc],,
       [AC_DEFINE(HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT, 1,
 	  [Define if your assembler supports eh_frame pcrel encoding.])])
+    gcc_GAS_CHECK_FEATURE([-mrelax option], gcc_cv_as_loongarch_relax,
+      [-mrelax], [.text],,
+      [AC_DEFINE(HAVE_AS_MRELAX_OPTION, 1,
+		[Define if your assembler supports -mrelax option.])])
     ;;
     s390*-*-*)
     gcc_GAS_CHECK_FEATURE([.gnu_attribute support],