runtime: add padding to FFI type of struct ending with zero-sized field
CL 157557 changes the compiler to add one byte padding to
non-empty struct ending with a zero-sized field. Add the same
padding to the FFI type, so reflect.Call works.
This fixes test/fixedbugs/issue26335.go in the main repo.
Change-Id: Idfb6b67c2cb6f3d00be5ac48492e55e4d8995cc3
Reviewed-on: https://go-review.googlesource.com/c/158018
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/runtime/ffi.go b/libgo/go/runtime/ffi.go
index 00858f1..e8088ec 100644
--- a/libgo/go/runtime/ffi.go
+++ b/libgo/go/runtime/ffi.go
@@ -227,6 +227,7 @@
fields := make([]*__ffi_type, 0, c+1)
checkPad := false
+ lastzero := false
for i, v := range typ.fields {
// Skip zero-sized fields; they confuse libffi,
// and there is no value to pass in any case.
@@ -235,8 +236,10 @@
// next field.
if v.typ.size == 0 {
checkPad = true
+ lastzero = true
continue
}
+ lastzero = false
if checkPad {
off := uintptr(0)
@@ -257,6 +260,13 @@
fields = append(fields, typeToFFI(v.typ))
}
+ if lastzero {
+ // The compiler adds one byte padding to non-empty struct ending
+ // with a zero-sized field (types.cc:get_backend_struct_fields).
+ // Add this padding to the FFI type.
+ fields = append(fields, ffi_type_uint8())
+ }
+
fields = append(fields, nil)
return &__ffi_type{
