win64: add a XMM clobber test configure option.

This will be useful to test more aggressively for failures to mark XMM
registers as clobbered in Win64 builds, and prevent regressions thereof.

Based on a patch by Ramiro Polla <ramiro.polla@gmail.com>

configure

@@ -254,6 +254,8 @@ Developer options (useful when working on Libav itself):
   --enable-extra-warnings  enable more compiler warnings
   --samples=PATH           location of test samples for FATE, if not set use
                            \$FATE_SAMPLES at make invocation time.
+  --enable-xmm-clobber-test check XMM registers for clobbering (Win64-only;
+                           should be used only for debugging purposes)
 
 NOTE: Object files are built at the place where configure is launched.
 EOF
@@ -991,6 +993,7 @@ CONFIG_LIST="
     vda
     vdpau
     version3
+    xmm_clobber_test
     x11grab
     zlib
 "
@@ -3065,6 +3068,17 @@ check_ldflags -Wl,--warn-common
 check_ldflags -Wl,-rpath-link=libpostproc:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil
 test_ldflags -Wl,-Bsymbolic && append SHFLAGS -Wl,-Bsymbolic
 
+enabled xmm_clobber_test &&                             \
+    check_ldflags -Wl,--wrap,avcodec_open2              \
+                  -Wl,--wrap,avcodec_decode_audio4      \
+                  -Wl,--wrap,avcodec_decode_video2      \
+                  -Wl,--wrap,avcodec_decode_subtitle2   \
+                  -Wl,--wrap,avcodec_encode_audio2      \
+                  -Wl,--wrap,avcodec_encode_video       \
+                  -Wl,--wrap,avcodec_encode_subtitle    \
+                  -Wl,--wrap,sws_scale ||               \
+    disable xmm_clobber_test
+
 echo "X{};" > $TMPV
 if test_ldflags -Wl,--version-script,$TMPV; then
     append SHFLAGS '-Wl,--version-script,\$(SUBDIR)lib\$(NAME).ver'

libavcodec/x86/Makefile

@@ -74,3 +74,4 @@ OBJS-$(HAVE_MMX)                       += x86/dsputil_mmx.o             \
                                           x86/mpegvideo_mmx.o           \
                                           x86/simple_idct_mmx.o         \
 
+OBJS-$(CONFIG_XMM_CLOBBER_TEST)        += x86/w64xmmtest.o

libavcodec/x86/w64xmmtest.c

@@ -0,0 +1,80 @@
+/*
+ * check XMM registers for clobbers on Win64
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavcodec/avcodec.h"
+#include "libavutil/x86/w64xmmtest.h"
+
+wrap(avcodec_open2(AVCodecContext *avctx,
+                   AVCodec *codec,
+                   AVDictionary **options))
+{
+    testxmmclobbers(avcodec_open2, avctx, codec, options);
+}
+
+wrap(avcodec_decode_audio4(AVCodecContext *avctx,
+                           AVFrame *frame,
+                           int *got_frame_ptr,
+                           AVPacket *avpkt))
+{
+    testxmmclobbers(avcodec_decode_audio4, avctx, frame,
+                    got_frame_ptr, avpkt);
+}
+
+wrap(avcodec_decode_video2(AVCodecContext *avctx,
+                           AVFrame *picture,
+                           int *got_picture_ptr,
+                           AVPacket *avpkt))
+{
+    testxmmclobbers(avcodec_decode_video2, avctx, picture,
+                    got_picture_ptr, avpkt);
+}
+
+wrap(avcodec_decode_subtitle2(AVCodecContext *avctx,
+                              AVSubtitle *sub,
+                              int *got_sub_ptr,
+                              AVPacket *avpkt))
+{
+    testxmmclobbers(avcodec_decode_subtitle2, avctx, sub,
+                    got_sub_ptr, avpkt);
+}
+
+wrap(avcodec_encode_audio2(AVCodecContext *avctx,
+                           AVPacket *avpkt,
+                           const AVFrame *frame,
+                           int *got_packet_ptr))
+{
+    testxmmclobbers(avcodec_encode_audio2, avctx, avpkt, frame,
+                    got_packet_ptr);
+}
+
+wrap(avcodec_encode_video(AVCodecContext *avctx,
+                          uint8_t *buf, int buf_size,
+                          const AVFrame *pict))
+{
+    testxmmclobbers(avcodec_encode_video, avctx, buf, buf_size, pict);
+}
+
+wrap(avcodec_encode_subtitle(AVCodecContext *avctx,
+                             uint8_t *buf, int buf_size,
+                             const AVSubtitle *sub))
+{
+    testxmmclobbers(avcodec_encode_subtitle, avctx, buf, buf_size, sub);
+}

libavutil/x86/w64xmmtest.h

@@ -0,0 +1,71 @@
+/*
+ * check XMM registers for clobbers on Win64
+ * Copyright (c) 2008 Ramiro Polla <ramiro.polla@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "libavutil/bswap.h"
+
+#define storexmmregs(mem)               \
+    __asm__ volatile(                   \
+        "movups %%xmm6 , 0x00(%0)\n\t"  \
+        "movups %%xmm7 , 0x10(%0)\n\t"  \
+        "movups %%xmm8 , 0x20(%0)\n\t"  \
+        "movups %%xmm9 , 0x30(%0)\n\t"  \
+        "movups %%xmm10, 0x40(%0)\n\t"  \
+        "movups %%xmm11, 0x50(%0)\n\t"  \
+        "movups %%xmm12, 0x60(%0)\n\t"  \
+        "movups %%xmm13, 0x70(%0)\n\t"  \
+        "movups %%xmm14, 0x80(%0)\n\t"  \
+        "movups %%xmm15, 0x90(%0)\n\t"  \
+        :: "r"(mem) : "memory")
+
+#define testxmmclobbers(func, ctx, ...)                         \
+    uint64_t xmm[2][10][2];                                     \
+    int ret;                                                    \
+    storexmmregs(xmm[0]);                                       \
+    ret = __real_ ## func(ctx, __VA_ARGS__);                    \
+    storexmmregs(xmm[1]);                                       \
+    if (memcmp(xmm[0], xmm[1], sizeof(xmm[0]))) {               \
+        int i;                                                  \
+        av_log(ctx, AV_LOG_ERROR,                               \
+               "XMM REGS CLOBBERED IN %s!\n", #func);           \
+        for (i = 0; i < 10; i ++)                               \
+            if (xmm[0][i][0] != xmm[1][i][0] ||                 \
+                xmm[0][i][1] != xmm[1][i][1]) {                 \
+                av_log(ctx, AV_LOG_ERROR,                       \
+                       "xmm%-2d = %016"PRIx64"%016"PRIx64"\n",  \
+                       6 + i, av_bswap64(xmm[0][i][0]),         \
+                       av_bswap64(xmm[0][i][1]));               \
+                av_log(ctx, AV_LOG_ERROR,                       \
+                         "     -> %016"PRIx64"%016"PRIx64"\n",  \
+                       av_bswap64(xmm[1][i][0]),                \
+                       av_bswap64(xmm[1][i][1]));               \
+            }                                                   \
+        abort();                                                \
+    }                                                           \
+    return ret
+
+#define wrap(func)      \
+int __real_ ## func;    \
+int __wrap_ ## func;    \
+int __wrap_ ## func

libswscale/Makefile

@@ -21,6 +21,8 @@ MMX-OBJS-$(HAVE_YASM)      +=  x86/input.o              \
                                x86/output.o             \
                                x86/scale.o
 
+OBJS-$(CONFIG_XMM_CLOBBER_TEST) += x86/w64xmmtest.o
+
 TESTPROGS = colorspace swscale
 
 DIRS = bfin mlib ppc sparc x86

libswscale/x86/w64xmmtest.c

@@ -0,0 +1,31 @@
+/*
+ * check XMM registers for clobbers on Win64
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/x86/w64xmmtest.h"
+#include "libswscale/swscale.h"
+
+wrap(sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[],
+               const int srcStride[], int srcSliceY, int srcSliceH,
+               uint8_t *const dst[], const int dstStride[]))
+{
+    testxmmclobbers(sws_scale, c, srcSlice, srcStride, srcSliceY,
+                    srcSliceH, dst, dstStride);
+}