Index: libffi/doc/libffi.texi
===================================================================
--- libffi.orig/doc/libffi.texi
+++ libffi/doc/libffi.texi
@@ -171,7 +171,9 @@ discarded.
@var{avalues} is a vector of @code{void *} pointers that point to the
memory locations holding the argument values for a call. If @var{cif}
declares that the function has no arguments (i.e., @var{nargs} was 0),
-then @var{avalues} is ignored.
+then @var{avalues} is ignored. Note that argument values may be
+modified by the callee (for instance, structs passed by value); the
+burden of copying pass-by-value arguments is placed on the caller.
@end defun
Index: libffi/src/x86/ffi.c
===================================================================
--- libffi.orig/src/x86/ffi.c
+++ libffi/src/x86/ffi.c
@@ -291,27 +291,8 @@ void ffi_call(ffi_cif *cif, void (*fn)(v
{
#ifdef X86_WIN64
case FFI_WIN64:
- {
- /* Make copies of all struct arguments
- NOTE: not sure if responsibility should be here or in caller */
- unsigned int i;
- for (i=0; i < cif->nargs;i++) {
- size_t size = cif->arg_types[i]->size;
- if ((cif->arg_types[i]->type == FFI_TYPE_STRUCT
- && (size != 1 && size != 2 && size != 4 && size != 8))
-#if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
- || cif->arg_types[i]->type == FFI_TYPE_LONGDOUBLE
-#endif
- )
- {
- void *local = alloca(size);
- memcpy(local, avalue[i], size);
- avalue[i] = local;
- }
- }
- ffi_call_win64(ffi_prep_args, &ecif, cif->bytes,
- cif->flags, ecif.rvalue, fn);
- }
+ ffi_call_win64(ffi_prep_args, &ecif, cif->bytes,
+ cif->flags, ecif.rvalue, fn);
break;
#elif defined(X86_WIN32)
case FFI_SYSV:
Index: libffi/ChangeLog
===================================================================
--- libffi.orig/ChangeLog
+++ libffi/ChangeLog
@@ -8,6 +8,14 @@
* src/closures.c (selinux_enabled_check): Fix strncmp usage bug.
+2010-05-11 Dan Witte <dwitte@mozilla.com>
+
+ * doc/libffi.tex: Document previous change.
+
+2010-05-11 Makoto Kato <m_kato@ga2.so-net.ne.jp>
+
+ * src/x86/ffi.c (ffi_call): Don't copy structs passed by value.
+
2010-05-05 Michael Kohler <michaelkohler@live.com>
* src/dlmalloc.c (dlfree): Fix spelling.
