From fa297566f193066e7fc002c90bdf34414e152442 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 25 Apr 2013 08:07:10 -0600
Subject: [PATCH] libffi fix

Closes PR 13707
---
 src/foreign/README               | 3 +++
 src/foreign/libffi/src/x86/ffi.c | 7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/foreign/README b/src/foreign/README
index 99f018a156..ea4635381e 100644
--- a/src/foreign/README
+++ b/src/foreign/README
@@ -20,6 +20,9 @@ Local changes:
  * In "x86/darwin.S", added ".long 0" after ".LFE3:" to avoid
    linker problems compiling with gcc-4.0 on Mac OS X 10.7.
 
+ * In "x86/ffi.c" for Win32, don't try to align stack for
+   stdcall, fastcall, or thiscall.
+
 ========== libffi_msvc directory =====================================
 
 This directory is synced from the CTypes repository
diff --git a/src/foreign/libffi/src/x86/ffi.c b/src/foreign/libffi/src/x86/ffi.c
index 0600414d45..aa1808745e 100644
--- a/src/foreign/libffi/src/x86/ffi.c
+++ b/src/foreign/libffi/src/x86/ffi.c
@@ -315,7 +315,12 @@ ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
   cif->bytes += 4 * sizeof(ffi_arg);
 #endif
 
-  cif->bytes = (cif->bytes + 15) & ~0xF;
+#ifdef X86_WIN32
+  if ((cif->abi != FFI_STDCALL)
+      && (cif->abi != FFI_FASTCALL)
+      && (cif->abi != FFI_THISCALL))
+#endif
+    cif->bytes = (cif->bytes + 15) & ~0xF;
 
   return FFI_OK;
 }