src/runtime/syscall_windows.go - go - Git at Google

 // 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 (
 	"internal/abi"
 	"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", "arm64":
 		// On ARM and ARM64, 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 != "386" && (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.
 			// So basically we only support 386.
 			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.
 		// TODO(rsc): On arm and arm64 do we need to skip the caller's saved LR?
 		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.
 	//
 	// Pass a dummy RegArgs for now.
 	// TODO(mknyszek): Pass arguments in registers.
 	var regs abi.RegArgs
 	reflectcall(nil, unsafe.Pointer(c.fn), noescape(goArgs), uint32(c.retOffset)+sys.PtrSize, uint32(c.retOffset), uint32(c.retOffset)+sys.PtrSize, &regs)

 	// 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 //go:cgo_unsafe_args
 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
 }
	// 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 (
	"internal/abi"
	"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", "arm64":
	// On ARM and ARM64, 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 != "386" && (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.
	// So basically we only support 386.
	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.
	// TODO(rsc): On arm and arm64 do we need to skip the caller's saved LR?
	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.
	//
	// Pass a dummy RegArgs for now.
	// TODO(mknyszek): Pass arguments in registers.
	var regs abi.RegArgs
	reflectcall(nil, unsafe.Pointer(c.fn), noescape(goArgs), uint32(c.retOffset)+sys.PtrSize, uint32(c.retOffset), uint32(c.retOffset)+sys.PtrSize, &regs)

	// 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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	//go:cgo_unsafe_args
	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
	}