[FFmpeg-cvslog] Compile x86/swscale_template with -mno-red-zone.

[Reimar Döffinger]

ffmpeg | branch: master | Reimar Döffinger <Reimar.Doeffinger at gmx.de> | Wed Sep 21 19:10:58 2011 +0200| [424bcc46b5fb0d662e0fb9ad6319c5b9ef3d770f] | committer: Reimar Döffinger

Compile x86/swscale_template with -mno-red-zone.

Replaces a very hackish hack to fix the same issue (call instruction
overwriting stack variables).

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger at gmx.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=424bcc46b5fb0d662e0fb9ad6319c5b9ef3d770f
---

 configure                         |    5 +++++
 libswscale/Makefile               |    2 ++
 libswscale/x86/swscale_template.c |   10 ----------
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/configure b/configure
index 7c1a54e..862f851 100755
--- a/configure
+++ b/configure
@@ -3179,6 +3179,10 @@ else
 fi
 check_cflags -fno-math-errno
 check_cflags -fno-signed-zeros
+check_cc -mno-red-zone <<EOF && noredzone_flags="-mno-red-zone"
+int x;
+EOF
+
 
 if enabled icc; then
     # Just warnings, no remarks
@@ -3469,6 +3473,7 @@ SLIB_INSTALL_LINKS=${SLIB_INSTALL_LINKS}
 SLIB_INSTALL_EXTRA_LIB=${SLIB_INSTALL_EXTRA_LIB}
 SLIB_INSTALL_EXTRA_SHLIB=${SLIB_INSTALL_EXTRA_SHLIB}
 SAMPLES:=${samples:-\$(FATE_SAMPLES)}
+NOREDZONE_FLAGS=$noredzone_flags
 EOF
 
 get_version(){
diff --git a/libswscale/Makefile b/libswscale/Makefile
index 7f74677..942545d 100644
--- a/libswscale/Makefile
+++ b/libswscale/Makefile
@@ -21,6 +21,8 @@ OBJS-$(HAVE_MMX)           +=  x86/rgb2rgb.o            \
 OBJS-$(HAVE_VIS)           +=  sparc/yuv2rgb_vis.o
 OBJS-$(HAVE_YASM)          +=  x86/scale.o
 
+$(SUBDIR)x86/swscale_mmx.o: CFLAGS += $(NOREDZONE_FLAGS)
+
 TESTPROGS = colorspace swscale
 
 DIRS = bfin mlib ppc sparc x86
diff --git a/libswscale/x86/swscale_template.c b/libswscale/x86/swscale_template.c
index 6a143f7..35839be 100644
--- a/libswscale/x86/swscale_template.c
+++ b/libswscale/x86/swscale_template.c
@@ -1963,10 +1963,6 @@ static void RENAME(hyscale_fast)(SwsContext *c, int16_t *dst,
 #if defined(PIC)
     DECLARE_ALIGNED(8, uint64_t, ebxsave);
 #endif
-    // HACK: gcc 4.6 no longer decrements esp,
-    // use this to make it reserve space for the call
-    // return address
-    void *dummy;
 
     __asm__ volatile(
 #if defined(PIC)
@@ -2018,7 +2014,6 @@ static void RENAME(hyscale_fast)(SwsContext *c, int16_t *dst,
 #if defined(PIC)
           ,"m" (ebxsave)
 #endif
-          ,"m" (dummy)
         : "%"REG_a, "%"REG_c, "%"REG_d, "%"REG_S, "%"REG_D
 #if !defined(PIC)
          ,"%"REG_b
@@ -2040,10 +2035,6 @@ static void RENAME(hcscale_fast)(SwsContext *c, int16_t *dst1, int16_t *dst2,
 #if defined(PIC)
     DECLARE_ALIGNED(8, uint64_t, ebxsave);
 #endif
-    // HACK: gcc 4.6 no longer decrements esp,
-    // use this to make it reserve space for the call
-    // return address
-    void *dummy;
 
     __asm__ volatile(
 #if defined(PIC)
@@ -2083,7 +2074,6 @@ static void RENAME(hcscale_fast)(SwsContext *c, int16_t *dst1, int16_t *dst2,
 #if defined(PIC)
           ,"m" (ebxsave)
 #endif
-          ,"m" (dummy)
         : "%"REG_a, "%"REG_c, "%"REG_d, "%"REG_S, "%"REG_D
 #if !defined(PIC)
          ,"%"REG_b