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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package reflect
import (
"internal/goarch"
"unsafe"
)
// The makeFuncFFI function, written in C, fills in an FFI closure.
// It arranges for ffiCall to be invoked directly from FFI.
func makeFuncFFI(cif unsafe.Pointer, impl unsafe.Pointer)
// The makeCIF function, implemented in the runtime package, allocates a CIF.
func makeCIF(ft *funcType) unsafe.Pointer
// Export ffiCallbackGo so that C code in makefunc_ffi_c.c can call it.
//go:linkname ffiCallbackGo
// ffiCallbackGo implements the Go side of the libffi callback.
//
// The call chain arriving here looks like
// some_go_caller
// ->some_ffi_internals
// ->ffi_callback (in C)
// ->ffiCallbackGo
//
// 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, wordsize int32, bigEndian bool) {
ftyp := impl.typ
in := make([]Value, 0, len(ftyp.in))
ap := params
for _, rt := range ftyp.in {
p := unsafe_New(rt)
typedmemmove(rt, p, *(*unsafe.Pointer)(ap))
v := Value{rt, p, flag(rt.Kind()) | flagIndir}
in = append(in, v)
ap = (unsafe.Pointer)(uintptr(ap) + goarch.PtrSize)
}
out := impl.call(in)
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")
}
// 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
} else {
typedmemmove(typ, addr, v.ptr)
}
off += typ.size
}
}
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