Zebediah Figura : configure: Use -mpreferred-stack-boundary=2 on i386.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 4b458775bb8c9492ac859cfd167c5f54f245dec1
URL:    https://gitlab.winehq.org/wine/wine/-/commit/4b458775bb8c9492ac859cfd167c5f5...

Author: Zebediah Figura 
Date:   Thu Sep 21 15:38:15 2023 -0500

configure: Use -mpreferred-stack-boundary=2 on i386.

gcc currently assumes the stack alignment for i686-w64-mingw32 is 16, which is
essentially wrong. It works around this in most cases by applying -mstackrealign
when SSE is in use. However, this doesn't address the case of manually aligned
types (i.e. DECLSPEC_ALIGN), and it also for some reason doesn't seem to apply
when -mavx512f is in use, which seems to be an independent gcc bug.

The correct solution on the gcc end is not to assume that the stack is 4-byte
aligned. -mpreferred-stack-boundary=2 achieves exactly this, and there is motion
upstream to address this by effectively making this setting the default. Since
this will take time to propagate downstream, though, it seems prudent to address
this bug locally by essentially applying the same fix downstream.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55007
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55899

---

configure    | 34 ++++++++++++++++++++++++++++++++++
 configure.ac |  1 +
 2 files changed, 35 insertions(+)

diff --git a/configure b/configure
index 9219276d336..644d38e7288 100755
--- a/configure
+++ b/configure
@@ -11550,6 +11550,40 @@ printf "%s\n" "$ac_res" >&6; }
 if eval test "x$"$as_ac_var"" = x"yes"
 then :
   as_fn_append ${wine_arch}_EXTRACFLAGS " -fno-omit-frame-pointer"
+fi }
+            { as_ac_var=`printf "%s\n" "ac_cv_${wine_arch}_cflags_-mpreferred-stack-boundary=2" | $as_tr_sh`
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -mpreferred-stack-boundary=2" >&5
+printf %s "checking whether $CC supports -mpreferred-stack-boundary=2... " >&6; }
+if eval test ${$as_ac_var+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_wine_try_cflags_saved=$CFLAGS
+ac_wine_try_cflags_saved_exeext=$ac_exeext
+CFLAGS="$CFLAGS -nostdlib -nodefaultlibs -mpreferred-stack-boundary=2"
+ac_exeext=".exe"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+void *__os_arm64x_dispatch_ret = 0;
+int __cdecl mainCRTStartup(void) { return 0; }
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  eval "$as_ac_var=yes"
+else $as_nop
+  eval "$as_ac_var=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+CFLAGS=$ac_wine_try_cflags_saved
+ac_exeext=$ac_wine_try_cflags_saved_exeext
+fi
+eval ac_res=$$as_ac_var
+	       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+printf "%s\n" "$ac_res" >&6; }
+if eval test "x$"$as_ac_var"" = x"yes"
+then :
+  as_fn_append ${wine_arch}_EXTRACFLAGS " -mpreferred-stack-boundary=2"
 fi }
             { as_ac_var=`printf "%s\n" "ac_cv_${wine_arch}_cflags_-Wl,--disable-stdcall-fixup" | $as_tr_sh`
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wl,--disable-stdcall-fixup" >&5
diff --git a/configure.ac b/configure.ac
index 26bcc3f6c21..078856efe6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -991,6 +991,7 @@ This is an error since --enable-archs=$wine_arch was requested.])])

case $wine_arch in
       i386) WINE_TRY_PE_CFLAGS([-fno-omit-frame-pointer])
+            WINE_TRY_PE_CFLAGS([-mpreferred-stack-boundary=2])
             WINE_TRY_PE_CFLAGS([-Wl,--disable-stdcall-fixup],
                                [AS_VAR_APPEND([${wine_arch}_LDFLAGS],[" -Wl,--disable-stdcall-fixup"])]) ;;
       x86_64) WINE_TRY_PE_CFLAGS([-Wformat-overflow])