go.sys/windows: grab Syscall interface from the standard syscall package

Also provide stubs to call loadlibrary and getprocaddress, which are implemented
for package syscall by runtime/syscall_windows.goc.
Should get the windows go.sys build closer to green.

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/126170043

windows/asm_windows_386.s

@@ -5,3 +5,9 @@
 //
 // System calls for 386, Windows are implemented in runtime/syscall_windows.goc
 //
+
+TEXT ·getprocaddress(SB), 7, $0-8
+	JMP	syscall·getprocaddress(SB)
+
+TEXT ·loadlibrary(SB), 7, $0-4
+	JMP	syscall·loadlibrary(SB)

windows/asm_windows_amd64.s

@@ -5,3 +5,9 @@
 //
 // System calls for amd64, Windows are implemented in runtime/syscall_windows.goc
 //
+
+TEXT ·getprocaddress(SB), 7, $0-32
+	JMP	syscall·getprocaddress(SB)
+
+TEXT ·loadlibrary(SB), 7, $0-8
+	JMP	syscall·loadlibrary(SB)

windows/dll_windows.go

@@ -7,6 +7,7 @@ package windows
 import (
 	"sync"
 	"sync/atomic"
+	"syscall"
 	"unsafe"
 )
 
@@ -19,14 +20,9 @@ type DLLError struct {
 
 func (e *DLLError) Error() string { return e.Msg }
 
-// Implemented in runtime/syscall_windows.goc.
-func Syscall(trap, nargs, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
-func Syscall6(trap, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-func Syscall9(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
-func Syscall12(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12 uintptr) (r1, r2 uintptr, err Errno)
-func Syscall15(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2 uintptr, err Errno)
-func loadlibrary(filename *uint16) (handle uintptr, err Errno)                 // TODO: must be exported.
-func getprocaddress(handle uintptr, procname *uint8) (proc uintptr, err Errno) // TODO: must be exported.
+// Implemented in runtime/syscall_windows.goc; we provide jumps to them in our assembly file.
+func loadlibrary(filename *uint16) (handle uintptr, err Errno)
+func getprocaddress(handle uintptr, procname *uint8) (proc uintptr, err Errno)
 
 // A DLL implements access to a single DLL.
 type DLL struct {
@@ -124,37 +120,37 @@ func (p *Proc) Addr() uintptr {
 func (p *Proc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) {
 	switch len(a) {
 	case 0:
-		return Syscall(p.Addr(), uintptr(len(a)), 0, 0, 0)
+		return syscall.Syscall(p.Addr(), uintptr(len(a)), 0, 0, 0)
 	case 1:
-		return Syscall(p.Addr(), uintptr(len(a)), a[0], 0, 0)
+		return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], 0, 0)
 	case 2:
-		return Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], 0)
+		return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], 0)
 	case 3:
-		return Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], a[2])
+		return syscall.Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], a[2])
 	case 4:
-		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], 0, 0)
+		return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], 0, 0)
 	case 5:
-		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], 0)
+		return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], 0)
 	case 6:
-		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5])
+		return syscall.Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5])
 	case 7:
-		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], 0, 0)
+		return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], 0, 0)
 	case 8:
-		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], 0)
+		return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], 0)
 	case 9:
-		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8])
+		return syscall.Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8])
 	case 10:
-		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], 0, 0)
+		return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], 0, 0)
 	case 11:
-		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], 0)
+		return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], 0)
 	case 12:
-		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11])
+		return syscall.Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11])
 	case 13:
-		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], 0, 0)
+		return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], 0, 0)
 	case 14:
-		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], 0)
+		return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], 0)
 	case 15:
-		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14])
+		return syscall.Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14])
 	default:
 		panic("Call " + p.Name + " with too many arguments " + itoa(len(a)) + ".")
 	}

windows/mksyscall_windows.go

@@ -492,10 +492,7 @@ func (f *Fn) SyscallParamCount() int {
 // Syscall determines which SyscallX function to use for function f.
 func (f *Fn) Syscall() string {
 	c := f.SyscallParamCount()
-	if c == 3 {
-		return windowsdot() + "Syscall"
-	}
-	return windowsdot() + "Syscall" + strconv.Itoa(c)
+	return "syscall.Syscall" + strconv.Itoa(c)
 }
 
 // SyscallParamList returns source code for SyscallX parameters for function f.