From b7ec44e82bb50bd3adc294aa7e87252c79ea7294 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 15 Jan 2019 23:21:24 +0000 Subject: [PATCH] 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. Reviewed-on: https://go-review.googlesource.com/c/158018 From-SVN: r267956 --- gcc/go/gofrontend/MERGE | 2 +- libgo/go/runtime/ffi.go | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index 4d76c547bdc..b13915110b9 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -87005025fcd0d7e7908b3aae7062b52cb80eb0f3 +9a79c333e896ea49f6a708d459148074d29a2af6 The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/libgo/go/runtime/ffi.go b/libgo/go/runtime/ffi.go index 00858f19ab4..e8088ec3947 100644 --- a/libgo/go/runtime/ffi.go +++ b/libgo/go/runtime/ffi.go @@ -227,6 +227,7 @@ func structToFFI(typ *structtype) *__ffi_type { 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 @@ func structToFFI(typ *structtype) *__ffi_type { // next field. if v.typ.size == 0 { checkPad = true + lastzero = true continue } + lastzero = false if checkPad { off := uintptr(0) @@ -257,6 +260,13 @@ func structToFFI(typ *structtype) *__ffi_type { 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{ -- 2.30.2