[PATCH roland/arm] Conditionalize test-xfail-tst-tlsalign{,-static} on ARM assembler bug.

[Roland McGrath <roland at hack dot frob dot com>]

With HJ's x86 fix, the only known failures for tst-tlsalign (18383)
are due to the ARM assembler bug, which is fixed in current binutils
trunk and 2.25 branch (but broken in all released versions).

This adds a configure check for the bug, and makes the tests XFAIL only if
the assembler bug is there.

Tested on arm-linux-gnueabihf that the configure check fails with
binutils-2.24 and that it (and the no-longer-XFAIL tests) succeed
with binutils-2_25-branch.

OK?


Thanks,
Roland


2015-06-26  Roland McGrath  <roland@hack.frob.com>

	[BZ #18383]
	* sysdeps/arm/configure.ac (libc_cv_arm_tpoff_addend): New check.
	Emit test-xfail-tst-tlsalign{,-static}=yes if it fails.
	* sysdeps/arm/configure: Regenerated.
	* elf/Makefile (test-xfail-tst-tlsalign): Variable removed.
	(test-xfail-tst-tlsalign-static): Variable removed.

diff --git a/elf/Makefile b/elf/Makefile
index f21276c0..7fda056 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -524,10 +524,6 @@ $(objpfx)tst-initorder: $(objpfx)tst-initordera4.so $(objpfx)tst-initordera1.so
 $(objpfx)tst-null-argv: $(objpfx)tst-null-argv-lib.so
 $(objpfx)tst-tlsalign: $(objpfx)tst-tlsalign-lib.so
 
-# BZ#18383: broken on at least ARM (both).
-test-xfail-tst-tlsalign = yes
-test-xfail-tst-tlsalign-static = yes
-
 $(objpfx)tst-tlsalign-extern: $(objpfx)tst-tlsalign-vars.o
 $(objpfx)tst-tlsalign-extern-static: $(objpfx)tst-tlsalign-vars.o
 
diff --git a/sysdeps/arm/configure b/sysdeps/arm/configure
index 52f2185..f789f61 100644
--- a/sysdeps/arm/configure
+++ b/sysdeps/arm/configure
@@ -260,6 +260,52 @@ if test $libc_cv_arm_pcrel_movw = yes; then
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether TPOFF relocs with addends are assembled correctly" >&5
+$as_echo_n "checking whether TPOFF relocs with addends are assembled correctly... " >&6; }
+if ${libc_cv_arm_tpoff_addend+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+
+cat > conftest.s <<\EOF
+	.syntax unified
+	.arm
+	.arch armv7-a
+
+	.text
+foo:
+	.word tbase(tpoff)+4
+
+	.section .tdata,"awT",%progbits
+	.word -4
+tbase:	.word 0
+	.word 4
+EOF
+libc_cv_arm_tpoff_addend=no
+${CC-cc} -c $CFLAGS $CPPFLAGS \
+	 -o conftest.o conftest.s 1>&5 2>&5 &&
+LC_ALL=C $READELF -x.text conftest.o > conftest.x 2>&5 &&
+{
+  cat conftest.x 1>&5
+  $AWK 'BEGIN { result = 2 }
+$1 ~ /0x0+/ && $2 ~ /[0-9a-f]+/ {
+# Check for little-endian or big-endian encoding of 4 in the in-place addend.
+  result = ($2 == "04000000" || $2 == "00000004") ? 0 : 1
+}
+END { exit(result) }
+' conftest.x 2>&5 && libc_cv_arm_tpoff_addend=yes
+}
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_arm_tpoff_addend" >&5
+$as_echo "$libc_cv_arm_tpoff_addend" >&6; }
+if test $libc_cv_arm_tpoff_addend = no; then
+  config_vars="$config_vars
+test-xfail-tst-tlsalign = yes"
+  config_vars="$config_vars
+test-xfail-tst-tlsalign-static = yes"
+fi
+
+
 libc_cv_gcc_unwind_find_fde=no
 
 # Remove -fno-unwind-tables that was added in sysdeps/arm/preconfigure.ac.
diff --git a/sysdeps/arm/configure.ac b/sysdeps/arm/configure.ac
index 168f2e7..d7b6a7a 100644
--- a/sysdeps/arm/configure.ac
+++ b/sysdeps/arm/configure.ac
@@ -79,6 +79,43 @@ if test $libc_cv_arm_pcrel_movw = yes; then
   AC_DEFINE([ARM_PCREL_MOVW_OK])
 fi
 
+AC_CACHE_CHECK([whether TPOFF relocs with addends are assembled correctly],
+	       libc_cv_arm_tpoff_addend, [
+cat > conftest.s <<\EOF
+	.syntax unified
+	.arm
+	.arch armv7-a
+
+	.text
+foo:
+	.word tbase(tpoff)+4
+
+	.section .tdata,"awT",%progbits
+	.word -4
+tbase:	.word 0
+	.word 4
+EOF
+libc_cv_arm_tpoff_addend=no
+${CC-cc} -c $CFLAGS $CPPFLAGS \
+	 -o conftest.o conftest.s 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD &&
+LC_ALL=C $READELF -x.text conftest.o > conftest.x 2>&AS_MESSAGE_LOG_FD &&
+{
+  cat conftest.x 1>&AS_MESSAGE_LOG_FD
+  $AWK 'BEGIN { result = 2 }
+$1 ~ /0x0+/ && $2 ~ /[[0-9a-f]]+/ {
+# Check for little-endian or big-endian encoding of 4 in the in-place addend.
+  result = ($2 == "04000000" || $2 == "00000004") ? 0 : 1
+}
+END { exit(result) }
+' conftest.x 2>&AS_MESSAGE_LOG_FD && libc_cv_arm_tpoff_addend=yes
+}
+rm -f conftest*])
+if test $libc_cv_arm_tpoff_addend = no; then
+  LIBC_CONFIG_VAR([test-xfail-tst-tlsalign], [yes])
+  LIBC_CONFIG_VAR([test-xfail-tst-tlsalign-static], [yes])
+fi
+
+
 libc_cv_gcc_unwind_find_fde=no
 
 # Remove -fno-unwind-tables that was added in sysdeps/arm/preconfigure.ac.