Not pretty at all. But given the corresponding irritation in writing assembler
wrapper functions, it seems like it's about a wash.
Tested with and without HAVE_AS_AVX on x86_64-linux.
r~
commit 856dd9f4777fbafce3038e889e9a9bf48222215d
Author: Richard Henderson <r...@redhat.com>
Date: Wed Nov 9 16:28:45 2011 -0800
libitm: Work around assembler missing AVX insns.
diff --git a/libitm/ChangeLog b/libitm/ChangeLog
index b1629b1..8aeb589 100644
--- a/libitm/ChangeLog
+++ b/libitm/ChangeLog
@@ -1,5 +1,12 @@
2011-11-09 Richard Henderson <r...@redhat.com>
+ * acinclude.m4 (LIBITM_CHECK_AS_AVX): New.
+ * configure.ac: Use it.
+ * config.h.in, configure: Rebuild.
+ * config/x86/x86_avx.cc: Handle !HAVE_AS_AVX.
+
+2011-11-09 Richard Henderson <r...@redhat.com>
+
* barrier.tpl, memcpy.cc, memset.cc, method-wbetl.cc: Remove file.
* config/alpha/unaligned.h: Remove file.
* config/generic/unaligned.h: Remove file.
diff --git a/libitm/acinclude.m4 b/libitm/acinclude.m4
index 8fcde4b..58fbf42 100644
--- a/libitm/acinclude.m4
+++ b/libitm/acinclude.m4
@@ -95,6 +95,20 @@ AC_DEFUN([LIBITM_CHECK_SIZE_T_MANGLING], [
[Define to the letter to which size_t is mangled.])
])
+dnl Check if as supports AVX instructions.
+AC_DEFUN([LIBITM_CHECK_AS_AVX], [
+case "${target_cpu}" in
+i[3456]86 | x86_64)
+ AC_CACHE_CHECK([if the assembler supports AVX], libitm_cv_as_avx, [
+ AC_TRY_COMPILE([], [asm("vzeroupper");],
+ [libitm_cv_as_avx=yes], [libitm_cv_as_avx=no])
+ ])
+ if test x$libitm_cv_as_avx = xyes; then
+ AC_DEFINE(HAVE_AS_AVX, 1, [Define to 1 if the assembler supports AVX.])
+ fi
+ ;;
+esac])
+
sinclude(../libtool.m4)
dnl The lines below arrange for aclocal not to bring an installed
dnl libtool.m4 into aclocal.m4, while still arranging for automake to
diff --git a/libitm/config/x86/x86_avx.cc b/libitm/config/x86/x86_avx.cc
index 30420aa..cd20fe2 100644
--- a/libitm/config/x86/x86_avx.cc
+++ b/libitm/config/x86/x86_avx.cc
@@ -22,9 +22,66 @@
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
+#include "config.h"
+
+// ??? This is pretty gross, but we're going to frob types of the functions.
+// Is this better or worse than just admitting we need to do this in pure
+// assembly?
+
+#ifndef HAVE_AS_AVX
+#undef __AVX__
+#endif
+
#include "libitm_i.h"
#include "dispatch.h"
+extern "C" {
+
+#ifndef HAVE_AS_AVX
+typedef float _ITM_TYPE_M256 __attribute__((vector_size(32), may_alias));
+#endif
+
+// ??? Re-define the memcpy implementations so that we can frob the
+// interface to deal with possibly missing AVX instruction set support.
+
+#ifdef HAVE_AS_AVX
+#define RETURN(X) return X
+#define STORE(X,Y) X = Y
+#define OUTPUT(T) _ITM_TYPE_##T
+#define INPUT(T,X) , _ITM_TYPE_##T X
+#else
+/* Emit vmovaps (%rax),%ymm0. */
+#define RETURN(X) \
+ asm volatile(".byte 0xc5,0xfc,0x28,0x00" : "=m"(X) : "a"(&X));
+/* Emit vmovaps %ymm0,(%rax); vzeroupper. */
+#define STORE(X,Y) \
+ asm volatile(".byte 0xc5,0xfc,0x29,0x00,0xc5,0xf8,0x77" : "=m"(X) : "a"(&X));
+#define OUTPUT(T) void
+#define INPUT(T,X)
+#endif
+
+#undef ITM_READ_MEMCPY
+#define ITM_READ_MEMCPY(T, LSMOD, TARGET, M2) \
+OUTPUT(T) ITM_REGPARM _ITM_##LSMOD##T (const _ITM_TYPE_##T *ptr) \
+{ \
+ _ITM_TYPE_##T v; \
+ TARGET memtransfer##M2(&v, ptr, sizeof(_ITM_TYPE_##T), false,
\
+ GTM::abi_dispatch::NONTXNAL, \
+ GTM::abi_dispatch::LSMOD); \
+ RETURN(v); \
+}
+
+#undef ITM_WRITE_MEMCPY
+#define ITM_WRITE_MEMCPY(T, LSMOD, TARGET, M2) \
+void ITM_REGPARM _ITM_##LSMOD##T (_ITM_TYPE_##T *ptr INPUT(T,in)) \
+{ \
+ _ITM_TYPE_##T v; \
+ STORE(v, in);
\
+ TARGET memtransfer##M2(ptr, &v, sizeof(_ITM_TYPE_##T), false,
\
+ GTM::abi_dispatch::LSMOD, \
+ GTM::abi_dispatch::NONTXNAL); \
+}
+
// ??? Use memcpy for now, until we have figured out how to best instantiate
// these loads/stores.
CREATE_DISPATCH_FUNCTIONS_T_MEMCPY(M256, GTM::abi_disp()->, )
@@ -34,3 +91,5 @@ _ITM_LM256 (const _ITM_TYPE_M256 *ptr)
{
GTM::GTM_LB (ptr, sizeof (*ptr));
}
+
+}
diff --git a/libitm/configure.ac b/libitm/configure.ac
index c40ecb5..7de5cbe 100644
--- a/libitm/configure.ac
+++ b/libitm/configure.ac
@@ -237,6 +237,7 @@ CFLAGS="$save_CFLAGS $XCFLAGS"
# had a chance to set XCFLAGS.
LIBITM_CHECK_SYNC_BUILTINS
LIBITM_CHECK_64BIT_SYNC_BUILTINS
+LIBITM_CHECK_AS_AVX
# Cleanup and exit.
CFLAGS="$save_CFLAGS"
