Add empty SSSE3 implementation

This commit adds a new, empty SSSE3 implementation and the associated
build system support.

configure.ac:   detect whether the compiler understands SSSE3
                intrinsics and set up the required CFLAGS

Makefile.am:    Add libpixman-ssse3.la

pixman-x86.c:   Add X86_SSSE3 feature flag and detect it in
                detect_cpu_features().

pixman-ssse3.c: New file with an empty SSSE3 implementation

V2: Remove SSSE3_LDFLAGS since it isn't necessary unless Solaris
support is added.

configure.ac

@@ -436,6 +436,50 @@ fi
 
 AM_CONDITIONAL(USE_SSE2, test $have_sse2_intrinsics = yes)
 
+dnl ===========================================================================
+dnl Check for SSSE3
+
+if test "x$SSSE3_CFLAGS" = "x" ; then
+    SSSE3_CFLAGS="-mssse3 -Winline"
+fi
+
+have_ssse3_intrinsics=no
+AC_MSG_CHECKING(whether to use SSSE3 intrinsics)
+xserver_save_CFLAGS=$CFLAGS
+CFLAGS="$SSSE3_CFLAGS $CFLAGS"
+
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+#include <mmintrin.h>
+#include <xmmintrin.h>
+#include <emmintrin.h>
+#include <tmmintrin.h>
+int main () {
+    __m128i a = _mm_set1_epi32 (0), b = _mm_set1_epi32 (0), c;
+    c = _mm_maddubs_epi16 (a, b);
+    return 0;
+}]])], have_ssse3_intrinsics=yes)
+CFLAGS=$xserver_save_CFLAGS
+
+AC_ARG_ENABLE(ssse3,
+   [AC_HELP_STRING([--disable-ssse3],
+                   [disable SSSE3 fast paths])],
+   [enable_ssse3=$enableval], [enable_ssse3=auto])
+
+if test $enable_ssse3 = no ; then
+   have_ssse3_intrinsics=disabled
+fi
+
+if test $have_ssse3_intrinsics = yes ; then
+   AC_DEFINE(USE_SSSE3, 1, [use SSSE3 compiler intrinsics])
+fi
+
+AC_MSG_RESULT($have_ssse3_intrinsics)
+if test $enable_ssse3 = yes && test $have_ssse3_intrinsics = no ; then
+   AC_MSG_ERROR([SSSE3 intrinsics not detected])
+fi
+
+AM_CONDITIONAL(USE_SSSE3, test $have_ssse3_intrinsics = yes)
+
 dnl ===========================================================================
 dnl Other special flags needed when building code using MMX or SSE instructions
 case $host_os in
@@ -471,6 +515,7 @@ AC_SUBST(MMX_CFLAGS)
 AC_SUBST(MMX_LDFLAGS)
 AC_SUBST(SSE2_CFLAGS)
 AC_SUBST(SSE2_LDFLAGS)
+AC_SUBST(SSSE3_CFLAGS)
 
 dnl ===========================================================================
 dnl Check for VMX/Altivec

pixman/Makefile.am

@@ -52,6 +52,18 @@ libpixman_1_la_LIBADD += libpixman-sse2.la
 ASM_CFLAGS_sse2=$(SSE2_CFLAGS)
 endif
 
+# ssse3 code
+if USE_SSSE3
+noinst_LTLIBRARIES += libpixman-ssse3.la
+libpixman_ssse3_la_SOURCES = \
+	pixman-ssse3.c
+libpixman_ssse3_la_CFLAGS = $(SSSE3_CFLAGS)
+libpixman_1_la_LDFLAGS += $(SSSE3_LDFLAGS)
+libpixman_1_la_LIBADD += libpixman-ssse3.la
+
+ASM_CFLAGS_ssse3=$(SSSE3_CFLAGS)
+endif
+
 # arm simd code
 if USE_ARM_SIMD
 noinst_LTLIBRARIES += libpixman-arm-simd.la

pixman/pixman-private.h

@@ -593,6 +593,11 @@ pixman_implementation_t *
 _pixman_implementation_create_sse2 (pixman_implementation_t *fallback);
 #endif
 
+#ifdef USE_SSSE3
+pixman_implementation_t *
+_pixman_implementation_create_ssse3 (pixman_implementation_t *fallback);
+#endif
+
 #ifdef USE_ARM_SIMD
 pixman_implementation_t *
 _pixman_implementation_create_arm_simd (pixman_implementation_t *fallback);

pixman/pixman-ssse3.c

+/*
+ * Copyright © 2013 Soren Sandmann Pedersen
+ * Copyright © 2013 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Soren Sandmann (soren.sandmann@gmail.com)
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <mmintrin.h>
+#include <xmmintrin.h>
+#include <emmintrin.h>
+#include <tmmintrin.h>
+#include "pixman-private.h"
+#include "pixman-inlines.h"
+
+static const pixman_fast_path_t ssse3_fast_paths[] =
+{
+    { PIXMAN_OP_NONE },
+};
+
+pixman_implementation_t *
+_pixman_implementation_create_ssse3 (pixman_implementation_t *fallback)
+{
+    pixman_implementation_t *imp =
+	_pixman_implementation_create (fallback, ssse3_fast_paths);
+
+    return imp;
+}

pixman/pixman-x86.c

@@ -25,7 +25,7 @@
 
 #include "pixman-private.h"
 
-#if defined(USE_X86_MMX) || defined (USE_SSE2)
+#if defined(USE_X86_MMX) || defined (USE_SSE2) || defined (USE_SSSE3)
 
 /* The CPU detection code needs to be in a file not compiled with
  * "-mmmx -msse", as gcc would generate CMOV instructions otherwise
@@ -39,7 +39,8 @@ typedef enum
     X86_MMX_EXTENSIONS		= (1 << 1),
     X86_SSE			= (1 << 2) | X86_MMX_EXTENSIONS,
     X86_SSE2			= (1 << 3),
-    X86_CMOV			= (1 << 4)
+    X86_CMOV			= (1 << 4),
+    X86_SSSE3			= (1 << 5)
 } cpu_features_t;
 
 #ifdef HAVE_GETISAX
@@ -64,6 +65,8 @@ detect_cpu_features (void)
 	    features |= X86_SSE;
 	if (result & AV_386_SSE2)
 	    features |= X86_SSE2;
+	if (result & AV_386_SSSE3)
+	    features |= X86_SSSE3;
     }
 
     return features;
@@ -167,6 +170,8 @@ detect_cpu_features (void)
 	features |= X86_SSE;
     if (d & (1 << 26))
 	features |= X86_SSE2;
+    if (d & (1 << 9))
+	features |= X86_SSSE3;
 
     /* Check for AMD specific features */
     if ((features & X86_MMX) && !(features & X86_SSE))
@@ -222,6 +227,7 @@ _pixman_x86_get_implementations (pixman_implementation_t *imp)
 {
 #define MMX_BITS  (X86_MMX | X86_MMX_EXTENSIONS)
 #define SSE2_BITS (X86_MMX | X86_MMX_EXTENSIONS | X86_SSE | X86_SSE2)
+#define SSSE3_BITS (X86_SSE | X86_SSE2 | X86_SSSE3)
 
 #ifdef USE_X86_MMX
     if (!_pixman_disabled ("mmx") && have_feature (MMX_BITS))
@@ -233,5 +239,10 @@ _pixman_x86_get_implementations (pixman_implementation_t *imp)
 	imp = _pixman_implementation_create_sse2 (imp);
 #endif
 
+#ifdef USE_SSSE3
+    if (!_pixman_disabled ("ssse3") && have_feature (SSSE3_BITS))
+	imp = _pixman_implementation_create_ssse3 (imp);
+#endif
+
     return imp;
 }