runtime: remove nosplit directives from several Windows syscall helpers

Some of the Windows syscall helpers don't need to be nosplit. Removing
this directive will allow to add instrumentation to these functions
without having to worry about the stack size.

Change-Id: I3885621f23733af48563803c704563474010b8d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/572415
Reviewed-by: Than McIntosh <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

Author: qmuntal

src/runtime/os_windows.go

@@ -304,21 +304,6 @@ func monitorSuspendResume() {
 		uintptr(unsafe.Pointer(&params)), uintptr(unsafe.Pointer(&handle)))
 }
 
-//go:nosplit
-func getLoadLibrary() uintptr {
-	return uintptr(unsafe.Pointer(_LoadLibraryW))
-}
-
-//go:nosplit
-func getLoadLibraryEx() uintptr {
-	return uintptr(unsafe.Pointer(_LoadLibraryExW))
-}
-
-//go:nosplit
-func getGetProcAddress() uintptr {
-	return uintptr(unsafe.Pointer(_GetProcAddress))
-}
-
 func getproccount() int32 {
 	var mask, sysmask uintptr
 	ret := stdcall3(_GetProcessAffinityMask, currentProcess, uintptr(unsafe.Pointer(&mask)), uintptr(unsafe.Pointer(&sysmask)))

src/runtime/syscall_windows.go

@@ -414,10 +414,8 @@ func callbackWrap(a *callbackArgs) {
 const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
 
 //go:linkname syscall_loadsystemlibrary syscall.loadsystemlibrary
-//go:nosplit
 func syscall_loadsystemlibrary(filename *uint16) (handle, err uintptr) {
-	fn := getLoadLibraryEx()
-	handle, _, err = syscall_SyscallN(fn, uintptr(unsafe.Pointer(filename)), 0, _LOAD_LIBRARY_SEARCH_SYSTEM32)
+	handle, _, err = syscall_SyscallN(uintptr(unsafe.Pointer(_LoadLibraryExW)), uintptr(unsafe.Pointer(filename)), 0, _LOAD_LIBRARY_SEARCH_SYSTEM32)
 	KeepAlive(filename)
 	if handle != 0 {
 		err = 0
@@ -426,10 +424,8 @@ func syscall_loadsystemlibrary(filename *uint16) (handle, err uintptr) {
 }
 
 //go:linkname syscall_loadlibrary syscall.loadlibrary
-//go:nosplit
 func syscall_loadlibrary(filename *uint16) (handle, err uintptr) {
-	fn := getLoadLibrary()
-	handle, _, err = syscall_SyscallN(fn, uintptr(unsafe.Pointer(filename)))
+	handle, _, err = syscall_SyscallN(uintptr(unsafe.Pointer(_LoadLibraryW)), uintptr(unsafe.Pointer(filename)))
 	KeepAlive(filename)
 	if handle != 0 {
 		err = 0
@@ -438,10 +434,8 @@ func syscall_loadlibrary(filename *uint16) (handle, err uintptr) {
 }
 
 //go:linkname syscall_getprocaddress syscall.getprocaddress
-//go:nosplit
 func syscall_getprocaddress(handle uintptr, procname *byte) (outhandle, err uintptr) {
-	fn := getGetProcAddress()
-	outhandle, _, err = syscall_SyscallN(fn, handle, uintptr(unsafe.Pointer(procname)))
+	outhandle, _, err = syscall_SyscallN(uintptr(unsafe.Pointer(_GetProcAddress)), handle, uintptr(unsafe.Pointer(procname)))
 	KeepAlive(procname)
 	if outhandle != 0 {
 		err = 0