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[build] Disable hwcaps on libgfortran

Message ID ydd4m2iijr0.fsf@CeBiTec.Uni-Bielefeld.DE
State New
Headers show

Commit Message

Rainer Orth Dec. 5, 2016, 1:32 p.m. UTC 
The AVX-specific matmul patch for libgfortran broke Solaris/x86 testing
with /bin/as pretty badly: every single execution test involving
libgfortran.so now FAILs like

ld.so.1: alloc_comp_1.exe: fatal: /var/gcc/regression/trunk/10-gcc/build/i386-pc-solaris2.10/./libgfortran/.libs/libgfortran.so.4: hardware capability (CA_SUNW_HW_2) unsupported: 0x40  [ AVX2 ]
FAIL: gfortran.dg/coarray/alloc_comp_1.f90 -fcoarray=single  -O2  -latomic execution test

This happens because libgfortran.so now requires AVX and AVX2 support
from the executing system:

ro@zebrano 14 > elfdump -H libgfortran.so 

Capabilities Section:  .SUNW_cap

 Object Capabilities:
     index  tag               value
       [0]  CA_SUNW_HW_2     0x40  [ AVX2 ]
       [1]  CA_SUNW_HW_1     0x20001800  [ AVX SSE2 SSE ]

Since the relevant code is guarded by runtime test, this needs to be
disabled.  Fortunately, a similar problem has already been solved in
libitm and this patch just generalizes the solution:

* The autoconf macro checking for the -mclear-hwcaps compiler option
  (only available on Solaris at this time) is moved to a new
  config/hwcaps.m4, appropriately renamed.

* It's invoked in libgfortran.ac and the result added to the
  libgfortran.la LDFLAGS.

The patch below implements that.  It has been bootstrapped successfully
on i386-pc-solaris2.10 with both as/ld (where -mclear-hwcaps is present
and needed to avoid all those failures) and gas/gld (where
-mclear-hwcaps is present, but a no-op), and x86_64-pc-linux-gnu (where
the flag doesn't exist).  Testresults are back to normal for the first
configuration and unchanged for the other two.

Ok for mainline?

	Rainer
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Patch

# HG changeset patch
# Parent  652ae1c5b6c997f22956287c4158ac9bef51f7d3
Disable hwcaps on libgfortran

diff --git a/config/hwcaps.m4 b/config/hwcaps.m4
new file mode 100644
--- /dev/null
+++ b/config/hwcaps.m4
@@ -0,0 +1,28 @@ 
+dnl
+dnl Check if the linker used supports linker maps to clear hardware
+dnl capabilities.  This is only supported on Solaris at the moment.
+dnl
+dnl Defines:
+dnl  HWCAP_LDFLAGS=-mclear-hwcap if possible
+dnl  LD (as a side effect of testing)
+dnl
+AC_DEFUN([GCC_CHECK_LINKER_HWCAP], [
+  test -z "$HWCAP_LDFLAGS" && HWCAP_LDFLAGS=''
+  AC_REQUIRE([AC_PROG_LD])
+
+  ac_save_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LFLAGS -mclear-hwcap"
+
+  AC_MSG_CHECKING([for -mclear-hwcap])
+  AC_TRY_LINK([], [return 0;], [ac_hwcap_ldflags=yes],[ac_hwcap_ldflags=no])
+  if test "$ac_hwcap_ldflags" = "yes"; then
+    HWCAP_LDFLAGS="-mclear-hwcap $HWCAP_LDFLAGS"
+  fi
+  AC_MSG_RESULT($ac_hwcap_ldflags)
+
+  LDFLAGS="$ac_save_LDFLAGS"
+
+  AC_SUBST(HWCAP_LDFLAGS)
+
+  AM_CONDITIONAL(HAVE_HWCAP, test $ac_hwcap_ldflags != no)
+])
diff --git a/libgfortran/Makefile.am b/libgfortran/Makefile.am
--- a/libgfortran/Makefile.am
+++ b/libgfortran/Makefile.am
@@ -38,6 +38,7 @@  toolexeclib_DATA = libgfortran.spec
 libgfortran_la_LINK = $(LINK) $(libgfortran_la_LDFLAGS)
 libgfortran_la_LDFLAGS = -version-info `grep -v '^\#' $(srcdir)/libtool-version` \
 	$(LTLDFLAGS) $(LIBQUADLIB) ../libbacktrace/libbacktrace.la \
+	$(HWCAP_LDFLAGS) \
 	-lm $(extra_ldflags_libgfortran) \
 	$(version_arg) -Wc,-shared-libgcc
 libgfortran_la_DEPENDENCIES = $(version_dep) libgfortran.spec $(LIBQUADLIB_DEP)
diff --git a/libgfortran/configure.ac b/libgfortran/configure.ac
--- a/libgfortran/configure.ac
+++ b/libgfortran/configure.ac
@@ -222,6 +222,9 @@  fi
 AC_MSG_RESULT($ac_fdsections)
 AC_SUBST(SECTION_FLAGS)
 
+# Check linker hardware capability support.
+GCC_CHECK_LINKER_HWCAP
+
 # Find other programs we need.
 AC_CHECK_TOOL(AS, as)
 AC_CHECK_TOOL(AR, ar)
diff --git a/libitm/acinclude.m4 b/libitm/acinclude.m4
--- a/libitm/acinclude.m4
+++ b/libitm/acinclude.m4
@@ -300,36 +300,6 @@  AC_DEFUN([LIBITM_CHECK_LINKER_FEATURES],
 
 
 dnl
-dnl Check if the linker used supports linker maps to clear hardware
-dnl capabilities.  This is only supported on Solaris at the moment.
-dnl
-dnl Defines:
-dnl  HWCAP_LDFLAGS=-mclear-hwcap if possible
-dnl  LD (as a side effect of testing)
-dnl
-AC_DEFUN([LIBITM_CHECK_LINKER_HWCAP], [
-  test -z "$HWCAP_LDFLAGS" && HWCAP_LDFLAGS=''
-  AC_REQUIRE([AC_PROG_LD])
-
-  ac_save_LDFLAGS="$LDFLAGS"
-  LDFLAGS="$LFLAGS -mclear-hwcap"
-
-  AC_MSG_CHECKING([for -mclear-hwcap])
-  AC_TRY_LINK([], [return 0;], [ac_hwcap_ldflags=yes],[ac_hwcap_ldflags=no])
-  if test "$ac_hwcap_ldflags" = "yes"; then
-    HWCAP_LDFLAGS="-mclear-hwcap $HWCAP_LDFLAGS"
-  fi
-  AC_MSG_RESULT($ac_hwcap_ldflags)
-
-  LDFLAGS="$ac_save_LDFLAGS"
-
-  AC_SUBST(HWCAP_LDFLAGS)
-
-  AM_CONDITIONAL(HAVE_HWCAP, test $ac_hwcap_ldflags != no)
-])
-
-
-dnl
 dnl Add version tags to symbols in shared library (or not), additionally
 dnl marking other symbols as private/local (or not).
 dnl
diff --git a/libitm/configure.ac b/libitm/configure.ac
--- a/libitm/configure.ac
+++ b/libitm/configure.ac
@@ -215,7 +215,7 @@  LIBITM_CHECK_ATTRIBUTE_DLLEXPORT
 LIBITM_CHECK_ATTRIBUTE_ALIAS
 
 # Check linker hardware capability support.
-LIBITM_CHECK_LINKER_HWCAP
+GCC_CHECK_LINKER_HWCAP
 # If defaulting to -mavx, don't clear hwcaps.
 AC_CHECK_DECL([__AVX__], [HWCAP_LDFLAGS=''])