From e0b3e9d2cfe6a9a4c7ccb2cfd64290ede98efb57 Mon Sep 17 00:00:00 2001
From: Timothy Arceri <t_arceri@yahoo.com.au>
Date: Sun, 7 Dec 2014 00:09:40 +1100
Subject: [PATCH] mesa: Ensure stack is realigned on x86

Nowadays GCC assumes stack pointer is 16-byte aligned even on 32-bits, but that is an assumption OpenGL drivers (or any dynamic library for that matter) can't afford to make as there are many closed- and open- source application binaries out there that only assume 4-byte stack alignment.

https://bugs.freedesktop.org/show_bug.cgi?id=86788
---
 configure.ac               | 17 +++++++++++++++++
 src/mesa/Makefile.am       |  4 ++++
 src/mesa/main/sse_minmax.c |  3 ---
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index b0df1bb..6bb43f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -474,6 +474,21 @@ fi
 dnl
 dnl Arch/platform-specific settings
 dnl
+align_check_arch=""
+if test "x$cross_compiling" = xno; then
+    case "$host_cpu" in
+        x86_64|amd64)
+            align_check_arch=x86_64
+    ;;
+    esac
+else
+    case "$host_cpu" in
+        i?86)
+            align_check_arch=x86_64
+    ;;
+    esac
+fi
+
 AC_ARG_ENABLE([asm],
     [AS_HELP_STRING([--disable-asm],
         [disable assembly usage @<:@default=enabled on supported plaforms@:>@])],
@@ -2087,6 +2102,8 @@ AM_CONDITIONAL(HAVE_X11_DRIVER, test "x$enable_xlib_glx" = xyes)
 AM_CONDITIONAL(HAVE_OSMESA, test "x$enable_osmesa" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_OSMESA, test "x$enable_gallium_osmesa" = xyes)
 
+AM_CONDITIONAL(HAVE_16BYTE_ALIGN, test "x$align_check_arch" = xx86_64)
+
 AM_CONDITIONAL(HAVE_X86_ASM, test "x$asm_arch" = xx86 -o "x$asm_arch" = xx86_64)
 AM_CONDITIONAL(HAVE_X86_64_ASM, test "x$asm_arch" = xx86_64)
 AM_CONDITIONAL(HAVE_SPARC_ASM, test "x$asm_arch" = xsparc)
diff --git a/src/mesa/Makefile.am b/src/mesa/Makefile.am
index 932db4f..36d4223 100644
--- a/src/mesa/Makefile.am
+++ b/src/mesa/Makefile.am
@@ -153,7 +153,11 @@ libmesagallium_la_LIBADD = \
 libmesa_sse41_la_SOURCES = \
 	main/streaming-load-memcpy.c \
 	main/sse_minmax.c
+if HAVE_16BYTE_ALIGN
 libmesa_sse41_la_CFLAGS = $(AM_CFLAGS) -msse4.1
+else
+libmesa_sse41_la_CFLAGS = $(AM_CFLAGS) -msse4.1 -mstackrealign
+endif
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = gl.pc
diff --git a/src/mesa/main/sse_minmax.c b/src/mesa/main/sse_minmax.c
index 93cf2a6..222ac14 100644
--- a/src/mesa/main/sse_minmax.c
+++ b/src/mesa/main/sse_minmax.c
@@ -31,9 +31,6 @@
 #include <stdint.h>
 
 void
-#if !defined(__x86_64__)
-   __attribute__((force_align_arg_pointer))
-#endif
 _mesa_uint_array_min_max(const unsigned *ui_indices, unsigned *min_index,
                          unsigned *max_index, const unsigned count)
 {
-- 
1.9.3