1 files changed, 397 insertions, 0 deletions
diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go
new file mode 100644
index 0000000..7835b49
--- /dev/null
+++ b/src/runtime/syscall_windows.go
@@ -0,0 +1,397 @@
+// 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 runtime
+
+import (
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+// cbs stores all registered Go callbacks.
+var cbs struct {
+	lock  mutex
+	ctxt  [cb_max]winCallback
+	index map[winCallbackKey]int
+	n     int
+}
+
+// winCallback records information about a registered Go callback.
+type winCallback struct {
+	fn     *funcval // Go function
+	retPop uintptr  // For 386 cdecl, how many bytes to pop on return
+
+	// abiMap specifies how to translate from a C frame to a Go
+	// frame. This does not specify how to translate back because
+	// the result is always a uintptr. If the C ABI is fastcall,
+	// this assumes the four fastcall registers were first spilled
+	// to the shadow space.
+	abiMap []abiPart
+	// retOffset is the offset of the uintptr-sized result in the Go
+	// frame.
+	retOffset uintptr
+}
+
+// abiPart encodes a step in translating between calling ABIs.
+type abiPart struct {
+	src, dst uintptr
+	len      uintptr
+}
+
+func (a *abiPart) tryMerge(b abiPart) bool {
+	if a.src+a.len == b.src && a.dst+a.len == b.dst {
+		a.len += b.len
+		return true
+	}
+	return false
+}
+
+type winCallbackKey struct {
+	fn    *funcval
+	cdecl bool
+}
+
+func callbackasm()
+
+// callbackasmAddr returns address of runtime.callbackasm
+// function adjusted by i.
+// On x86 and amd64, runtime.callbackasm is a series of CALL instructions,
+// and we want callback to arrive at
+// correspondent call instruction instead of start of
+// runtime.callbackasm.
+// On ARM, runtime.callbackasm is a series of mov and branch instructions.
+// R12 is loaded with the callback index. Each entry is two instructions,
+// hence 8 bytes.
+func callbackasmAddr(i int) uintptr {
+	var entrySize int
+	switch GOARCH {
+	default:
+		panic("unsupported architecture")
+	case "386", "amd64":
+		entrySize = 5
+	case "arm":
+		// On ARM, each entry is a MOV instruction
+		// followed by a branch instruction
+		entrySize = 8
+	}
+	return funcPC(callbackasm) + uintptr(i*entrySize)
+}
+
+const callbackMaxFrame = 64 * sys.PtrSize
+
+// compileCallback converts a Go function fn into a C function pointer
+// that can be passed to Windows APIs.
+//
+// On 386, if cdecl is true, the returned C function will use the
+// cdecl calling convention; otherwise, it will use stdcall. On amd64,
+// it always uses fastcall. On arm, it always uses the ARM convention.
+//
+//go:linkname compileCallback syscall.compileCallback
+func compileCallback(fn eface, cdecl bool) (code uintptr) {
+	if GOARCH != "386" {
+		// cdecl is only meaningful on 386.
+		cdecl = false
+	}
+
+	if fn._type == nil || (fn._type.kind&kindMask) != kindFunc {
+		panic("compileCallback: expected function with one uintptr-sized result")
+	}
+	ft := (*functype)(unsafe.Pointer(fn._type))
+
+	// Check arguments and construct ABI translation.
+	var abiMap []abiPart
+	var src, dst uintptr
+	for _, t := range ft.in() {
+		if t.size > sys.PtrSize {
+			// We don't support this right now. In
+			// stdcall/cdecl, 64-bit ints and doubles are
+			// passed as two words (little endian); and
+			// structs are pushed on the stack. In
+			// fastcall, arguments larger than the word
+			// size are passed by reference. On arm,
+			// 8-byte aligned arguments round up to the
+			// next even register and can be split across
+			// registers and the stack.
+			panic("compileCallback: argument size is larger than uintptr")
+		}
+		if k := t.kind & kindMask; (GOARCH == "amd64" || GOARCH == "arm") && (k == kindFloat32 || k == kindFloat64) {
+			// In fastcall, floating-point arguments in
+			// the first four positions are passed in
+			// floating-point registers, which we don't
+			// currently spill. arm passes floating-point
+			// arguments in VFP registers, which we also
+			// don't support.
+			panic("compileCallback: float arguments not supported")
+		}
+
+		// The Go ABI aligns arguments.
+		dst = alignUp(dst, uintptr(t.align))
+		// In the C ABI, we're already on a word boundary.
+		// Also, sub-word-sized fastcall register arguments
+		// are stored to the least-significant bytes of the
+		// argument word and all supported Windows
+		// architectures are little endian, so src is already
+		// pointing to the right place for smaller arguments.
+		// The same is true on arm.
+
+		// Copy just the size of the argument. Note that this
+		// could be a small by-value struct, but C and Go
+		// struct layouts are compatible, so we can copy these
+		// directly, too.
+		part := abiPart{src, dst, t.size}
+		// Add this step to the adapter.
+		if len(abiMap) == 0 || !abiMap[len(abiMap)-1].tryMerge(part) {
+			abiMap = append(abiMap, part)
+		}
+
+		// cdecl, stdcall, fastcall, and arm pad arguments to word size.
+		src += sys.PtrSize
+		// The Go ABI packs arguments.
+		dst += t.size
+	}
+	// The Go ABI aligns the result to the word size. src is
+	// already aligned.
+	dst = alignUp(dst, sys.PtrSize)
+	retOffset := dst
+
+	if len(ft.out()) != 1 {
+		panic("compileCallback: expected function with one uintptr-sized result")
+	}
+	if ft.out()[0].size != sys.PtrSize {
+		panic("compileCallback: expected function with one uintptr-sized result")
+	}
+	if k := ft.out()[0].kind & kindMask; k == kindFloat32 || k == kindFloat64 {
+		// In cdecl and stdcall, float results are returned in
+		// ST(0). In fastcall, they're returned in XMM0.
+		// Either way, it's not AX.
+		panic("compileCallback: float results not supported")
+	}
+	// Make room for the uintptr-sized result.
+	dst += sys.PtrSize
+
+	if dst > callbackMaxFrame {
+		panic("compileCallback: function argument frame too large")
+	}
+
+	// For cdecl, the callee is responsible for popping its
+	// arguments from the C stack.
+	var retPop uintptr
+	if cdecl {
+		retPop = src
+	}
+
+	key := winCallbackKey{(*funcval)(fn.data), cdecl}
+
+	lock(&cbs.lock) // We don't unlock this in a defer because this is used from the system stack.
+
+	// Check if this callback is already registered.
+	if n, ok := cbs.index[key]; ok {
+		unlock(&cbs.lock)
+		return callbackasmAddr(n)
+	}
+
+	// Register the callback.
+	if cbs.index == nil {
+		cbs.index = make(map[winCallbackKey]int)
+	}
+	n := cbs.n
+	if n >= len(cbs.ctxt) {
+		unlock(&cbs.lock)
+		throw("too many callback functions")
+	}
+	c := winCallback{key.fn, retPop, abiMap, retOffset}
+	cbs.ctxt[n] = c
+	cbs.index[key] = n
+	cbs.n++
+
+	unlock(&cbs.lock)
+	return callbackasmAddr(n)
+}
+
+type callbackArgs struct {
+	index uintptr
+	// args points to the argument block.
+	//
+	// For cdecl and stdcall, all arguments are on the stack.
+	//
+	// For fastcall, the trampoline spills register arguments to
+	// the reserved spill slots below the stack arguments,
+	// resulting in a layout equivalent to stdcall.
+	//
+	// For arm, the trampoline stores the register arguments just
+	// below the stack arguments, so again we can treat it as one
+	// big stack arguments frame.
+	args unsafe.Pointer
+	// Below are out-args from callbackWrap
+	result uintptr
+	retPop uintptr // For 386 cdecl, how many bytes to pop on return
+}
+
+// callbackWrap is called by callbackasm to invoke a registered C callback.
+func callbackWrap(a *callbackArgs) {
+	c := cbs.ctxt[a.index]
+	a.retPop = c.retPop
+
+	// Convert from C to Go ABI.
+	var frame [callbackMaxFrame]byte
+	goArgs := unsafe.Pointer(&frame)
+	for _, part := range c.abiMap {
+		memmove(add(goArgs, part.dst), add(a.args, part.src), part.len)
+	}
+
+	// Even though this is copying back results, we can pass a nil
+	// type because those results must not require write barriers.
+	reflectcall(nil, unsafe.Pointer(c.fn), noescape(goArgs), uint32(c.retOffset)+sys.PtrSize, uint32(c.retOffset))
+
+	// Extract the result.
+	a.result = *(*uintptr)(unsafe.Pointer(&frame[c.retOffset]))
+}
+
+const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
+
+// When available, this function will use LoadLibraryEx with the filename
+// parameter and the important SEARCH_SYSTEM32 argument. But on systems that
+// do not have that option, absoluteFilepath should contain a fallback
+// to the full path inside of system32 for use with vanilla LoadLibrary.
+//go:linkname syscall_loadsystemlibrary syscall.loadsystemlibrary
+//go:nosplit
+func syscall_loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (handle, err uintptr) {
+	lockOSThread()
+	c := &getg().m.syscall
+
+	if useLoadLibraryEx {
+		c.fn = getLoadLibraryEx()
+		c.n = 3
+		args := struct {
+			lpFileName *uint16
+			hFile      uintptr // always 0
+			flags      uint32
+		}{filename, 0, _LOAD_LIBRARY_SEARCH_SYSTEM32}
+		c.args = uintptr(noescape(unsafe.Pointer(&args)))
+	} else {
+		c.fn = getLoadLibrary()
+		c.n = 1
+		c.args = uintptr(noescape(unsafe.Pointer(&absoluteFilepath)))
+	}
+
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	handle = c.r1
+	if handle == 0 {
+		err = c.err
+	}
+	unlockOSThread() // not defer'd after the lockOSThread above to save stack frame size.
+	return
+}
+
+//go:linkname syscall_loadlibrary syscall.loadlibrary
+//go:nosplit
+func syscall_loadlibrary(filename *uint16) (handle, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = getLoadLibrary()
+	c.n = 1
+	c.args = uintptr(noescape(unsafe.Pointer(&filename)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	handle = c.r1
+	if handle == 0 {
+		err = c.err
+	}
+	return
+}
+
+//go:linkname syscall_getprocaddress syscall.getprocaddress
+//go:nosplit
+func syscall_getprocaddress(handle uintptr, procname *byte) (outhandle, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = getGetProcAddress()
+	c.n = 2
+	c.args = uintptr(noescape(unsafe.Pointer(&handle)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	outhandle = c.r1
+	if outhandle == 0 {
+		err = c.err
+	}
+	return
+}
+
+//go:linkname syscall_Syscall syscall.Syscall
+//go:nosplit
+func syscall_Syscall(fn, nargs, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}
+
+//go:linkname syscall_Syscall6 syscall.Syscall6
+//go:nosplit
+func syscall_Syscall6(fn, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}
+
+//go:linkname syscall_Syscall9 syscall.Syscall9
+//go:nosplit
+func syscall_Syscall9(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}
+
+//go:linkname syscall_Syscall12 syscall.Syscall12
+//go:nosplit
+func syscall_Syscall12(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}
+
+//go:linkname syscall_Syscall15 syscall.Syscall15
+//go:nosplit
+func syscall_Syscall15(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}
+
+//go:linkname syscall_Syscall18 syscall.Syscall18
+//go:nosplit
+func syscall_Syscall18(fn, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18 uintptr) (r1, r2, err uintptr) {
+	lockOSThread()
+	defer unlockOSThread()
+	c := &getg().m.syscall
+	c.fn = fn
+	c.n = nargs
+	c.args = uintptr(noescape(unsafe.Pointer(&a1)))
+	cgocall(asmstdcallAddr, unsafe.Pointer(c))
+	return c.r1, c.r2, c.err
+}