From 033425d0ed0092748fc919e5c40dc47421dcdd89 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 17 Sep 2019 20:24:00 +0000 Subject: re PR go/91781 (r275691 breaks go test "reflect") PR go/91781 reflect: promote integer closure return to full word The libffi library expects an integer return type to be promoted to a full word. Implement that when returning from a closure written in Go. This only matters on big-endian systems when returning an integer smaller than the pointer size, which is why we didn't notice it until now. Fixes https://gcc.gnu.org/PR91781. Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/195858 From-SVN: r275813 --- libgo/go/reflect/makefunc_ffi.go | 39 ++++++++++++++++++++++++++++++++------- libgo/go/reflect/makefunc_ffi_c.c | 6 ++++-- libgo/runtime/go-reflect-call.c | 12 ++++-------- 3 files changed, 40 insertions(+), 17 deletions(-) (limited to 'libgo') diff --git a/libgo/go/reflect/makefunc_ffi.go b/libgo/go/reflect/makefunc_ffi.go index 88ffca5..05c5bc0 100644 --- a/libgo/go/reflect/makefunc_ffi.go +++ b/libgo/go/reflect/makefunc_ffi.go @@ -28,7 +28,7 @@ func makeCIF(ft *funcType) unsafe.Pointer // // The ffi_callback handles __go_makefunc_can_recover, and // then passes off the data as received from ffi here. -func ffiCallbackGo(results unsafe.Pointer, params unsafe.Pointer, impl *makeFuncImpl) { +func ffiCallbackGo(results unsafe.Pointer, params unsafe.Pointer, impl *makeFuncImpl, wordsize int32, bigEndian bool) { ftyp := impl.typ in := make([]Value, 0, len(ftyp.in)) ap := params @@ -42,21 +42,46 @@ func ffiCallbackGo(results unsafe.Pointer, params unsafe.Pointer, impl *makeFunc out := impl.call(in) - off := uintptr(0) - for i, typ := range ftyp.out { - v := out[i] + checkValue := func(v Value, typ *rtype, addr unsafe.Pointer) { if v.flag&flagRO != 0 { panic("reflect: function created by MakeFunc using " + funcName(impl.fn) + " returned value obtained from unexported field") } - off = align(off, uintptr(typ.fieldAlign)) - addr := unsafe.Pointer(uintptr(results) + off) - // Convert v to type typ if v is assignable to a variable // of type t in the language spec. // See issue 28761. v = v.assignTo("reflect.MakeFunc", typ, addr) + } + + // In libffi a single integer return value is always promoted + // to a full word. This only matters for integers whose size + // is less than the size of a full word. There is similar code + // in libgo/runtime/go-reflect-call.c. + if len(ftyp.out) == 1 { + typ := ftyp.out[0] + switch typ.Kind() { + case Bool, Int8, Int16, Int32, Uint8, Uint16, Uint32: + v := out[0] + checkValue(v, typ, nil) + + if bigEndian { + results = unsafe.Pointer(uintptr(results) + uintptr(wordsize) - typ.size) + } + + memmove(results, v.ptr, typ.size) + return + } + } + + off := uintptr(0) + for i, typ := range ftyp.out { + v := out[i] + + off = align(off, uintptr(typ.fieldAlign)) + addr := unsafe.Pointer(uintptr(results) + off) + + checkValue(v, typ, addr) if v.flag&flagIndir == 0 && (v.kind() == Ptr || v.kind() == UnsafePointer) { *(*unsafe.Pointer)(addr) = v.ptr diff --git a/libgo/go/reflect/makefunc_ffi_c.c b/libgo/go/reflect/makefunc_ffi_c.c index e57bd51..f189026 100644 --- a/libgo/go/reflect/makefunc_ffi_c.c +++ b/libgo/go/reflect/makefunc_ffi_c.c @@ -25,7 +25,8 @@ void makeFuncFFI(void *cif, void *impl) function ffiCall with the pointer to the arguments, the results area, and the closure structure. */ -extern void ffiCallbackGo(void *result, void **args, ffi_go_closure *closure) +extern void ffiCallbackGo(void *result, void **args, ffi_go_closure *closure, + int32 wordsize, _Bool big_endian) __asm__ (GOSYM_PREFIX "reflect.ffiCallbackGo"); extern void makefuncfficanrecover(Slice) @@ -72,7 +73,8 @@ ffi_callback (ffi_cif* cif __attribute__ ((unused)), void *results, makefuncfficanrecover (s); } - ffiCallbackGo(results, args, closure); + ffiCallbackGo(results, args, closure, sizeof(ffi_arg), + __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__); if (i < n) makefuncreturning (); diff --git a/libgo/runtime/go-reflect-call.c b/libgo/runtime/go-reflect-call.c index ffae903..4d887eb 100644 --- a/libgo/runtime/go-reflect-call.c +++ b/libgo/runtime/go-reflect-call.c @@ -44,8 +44,8 @@ go_results_size (const struct functype *func) types = (const struct _type **) func->out.__values; - /* A single integer return value is always promoted to a full - word. */ + /* A single integer return value is always promoted to a full word. + There is similar code below and in libgo/go/reflect/makefunc_ffi.go.*/ if (count == 1) { switch (types[0]->kind & kindMask) @@ -57,8 +57,6 @@ go_results_size (const struct functype *func) case kindUint8: case kindUint16: case kindUint32: - case kindInt: - case kindUint: return sizeof (ffi_arg); default: @@ -108,8 +106,8 @@ go_set_results (const struct functype *func, unsigned char *call_result, types = (const struct _type **) func->out.__values; - /* A single integer return value is always promoted to a full - word. */ + /* A single integer return value is always promoted to a full word. + There is similar code above and in libgo/go/reflect/makefunc_ffi.go.*/ if (count == 1) { switch (types[0]->kind & kindMask) @@ -121,8 +119,6 @@ go_set_results (const struct functype *func, unsigned char *call_result, case kindUint8: case kindUint16: case kindUint32: - case kindInt: - case kindUint: { union { -- cgit v1.1