[PATCH] Check linker support for INSERT in linker script

["H.J. Lu" <hongjiu dot lu at intel dot com>]

Since gold doesn't support INSERT in linker script:

https://sourceware.org/bugzilla/show_bug.cgi?id=21676

tst-split-dynreloc fails to link with gold.  Check if linker supports
INSERT in linker script before using it.

Any comments?

H.J.
---
	* config.make.in (have-insert): New.
	* configure.ac (libc_cv_insert): New.  Set to yes if linker
	supports INSERT in linker script.
	(AC_SUBST(libc_cv_insert): New.
	* configure: Regenerated.
	* sysdeps/x86_64/Makefile (tests): Add tst-split-dynreloc only
	if $(have-insert) == yes.
---
 config.make.in          |  1 +
 configure               | 33 +++++++++++++++++++++++++++++++++
 configure.ac            | 21 +++++++++++++++++++++
 sysdeps/x86_64/Makefile |  2 ++
 4 files changed, 57 insertions(+)

diff --git a/config.make.in b/config.make.in
index dadabf9..c7edfc1 100644
--- a/config.make.in
+++ b/config.make.in
@@ -54,6 +54,7 @@ enable-werror = @enable_werror@
 have-z-combreloc = @libc_cv_z_combreloc@
 have-z-execstack = @libc_cv_z_execstack@
 have-protected-data = @libc_cv_protected_data@
+have-insert = @libc_cv_insert@
 have-glob-dat-reloc = @libc_cv_has_glob_dat@
 with-fp = @with_fp@
 enable-timezone-tools = @enable_timezone_tools@
diff --git a/configure b/configure
index b55fc92..a9ed3b3 100755
--- a/configure
+++ b/configure
@@ -629,6 +629,7 @@ libc_cv_z_execstack
 libc_cv_z_combreloc
 ASFLAGS_config
 libc_cv_cc_with_libunwind
+libc_cv_insert
 libc_cv_protected_data
 BISON
 INSTALL_INFO
@@ -5703,6 +5704,38 @@ fi
 $as_echo "$libc_cv_protected_data" >&6; }
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking linker support for INSERT in linker script" >&5
+$as_echo_n "checking linker support for INSERT in linker script... " >&6; }
+if ${libc_cv_insert+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.c <<EOF
+		const int __attribute__ ((section(".bar"))) bar = 0x12345678;
+		int test (void) { return bar; }
+EOF
+		cat > conftest.t <<EOF
+		SECTIONS
+		{
+		  .bar : { *(.bar) }
+		}
+		INSERT AFTER .rela.dyn;
+EOF
+		libc_cv_insert=no
+		if { ac_try='${CC-cc} -nostdlib -nostartfiles $no_ssp -fPIC -shared conftest.c -Wl,-T,conftest.t -o conftest.so'
+  { { eval echo "\"\$as_me\":${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
+		  libc_cv_insert=yes
+		fi
+		rm -f conftest.*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_insert" >&5
+$as_echo "$libc_cv_insert" >&6; }
+
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for broken __attribute__((alias()))" >&5
 $as_echo_n "checking for broken __attribute__((alias()))... " >&6; }
 if ${libc_cv_broken_alias_attribute+:} false; then :
diff --git a/configure.ac b/configure.ac
index 5f62ecb..807961f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1291,6 +1291,27 @@ EOF
 	       ])
 AC_SUBST(libc_cv_protected_data)
 
+AC_CACHE_CHECK(linker support for INSERT in linker script,
+	       libc_cv_insert,
+	       [cat > conftest.c <<EOF
+		const int __attribute__ ((section(".bar"))) bar = 0x12345678;
+		int test (void) { return bar; }
+EOF
+		cat > conftest.t <<EOF
+		SECTIONS
+		{
+		  .bar : { *(.bar) }
+		}
+		INSERT AFTER .rela.dyn;
+EOF
+		libc_cv_insert=no
+		if AC_TRY_COMMAND([${CC-cc} -nostdlib -nostartfiles $no_ssp -fPIC -shared conftest.c -Wl,-T,conftest.t -o conftest.so]); then
+		  libc_cv_insert=yes
+		fi
+		rm -f conftest.*
+	       ])
+AC_SUBST(libc_cv_insert)
+
 AC_CACHE_CHECK(for broken __attribute__((alias())),
 	       libc_cv_broken_alias_attribute,
 	       [cat > conftest.c <<EOF
diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
index 5075c91..948faa9 100644
--- a/sysdeps/x86_64/Makefile
+++ b/sysdeps/x86_64/Makefile
@@ -59,9 +59,11 @@ test-extras += tst-audit4-aux tst-audit10-aux \
 extra-test-objs += tst-audit4-aux.o tst-audit10-aux.o \
 		   tst-avx-aux.o tst-avx512-aux.o
 
+ifeq ($(have-insert),yes)
 tests += tst-split-dynreloc
 LDFLAGS-tst-split-dynreloc = -Wl,-T,$(..)sysdeps/x86_64/tst-split-dynreloc.lds
 tst-split-dynreloc-ENV = LD_BIND_NOW=1
+endif
 
 modules-names += tst-auditmod3a tst-auditmod3b \
 		tst-auditmod4a tst-auditmod4b \
-- 
2.9.4