runtime: allow to call stdcall from Go on windows

I've started with just one function with 8 arguments,
but stdcall is called from nosplit functions
and 8 args overflow nosplit area.

LGTM=aram, alex.brainman
R=golang-codereviews, aram, alex.brainman, dave
CC=golang-codereviews, iant, khr, rsc
https://golang.org/cl/135090043

src/pkg/runtime/mem_windows.c

@@ -29,7 +29,7 @@ void*
 runtime·SysAlloc(uintptr n, uint64 *stat)
 {
 	runtime·xadd64(stat, n);
-	return runtime·stdcall(runtime·VirtualAlloc, 4, nil, n, (uintptr)(MEM_COMMIT|MEM_RESERVE), (uintptr)PAGE_READWRITE);
+	return runtime·stdcall4(runtime·VirtualAlloc, 0, n, MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE);
 }
 
 void
@@ -38,7 +38,7 @@ runtime·SysUnused(void *v, uintptr n)
 	void *r;
 	uintptr small;
 
-	r = runtime·stdcall(runtime·VirtualFree, 3, v, n, (uintptr)MEM_DECOMMIT);
+	r = runtime·stdcall3(runtime·VirtualFree, (uintptr)v, n, MEM_DECOMMIT);
 	if(r != nil)
 		return;
 
@@ -53,7 +53,7 @@ runtime·SysUnused(void *v, uintptr n)
 	// in the worst case, but that's fast enough.
 	while(n > 0) {
 		small = n;
-		while(small >= 4096 && runtime·stdcall(runtime·VirtualFree, 3, v, small, (uintptr)MEM_DECOMMIT) == nil)
+		while(small >= 4096 && runtime·stdcall3(runtime·VirtualFree, (uintptr)v, small, MEM_DECOMMIT) == nil)
 			small = (small / 2) & ~(4096-1);
 		if(small < 4096)
 			runtime·throw("runtime: failed to decommit pages");
@@ -67,7 +67,7 @@ runtime·SysUsed(void *v, uintptr n)
 {
 	void *r;
 
-	r = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_COMMIT, (uintptr)PAGE_READWRITE);
+	r = runtime·stdcall4(runtime·VirtualAlloc, (uintptr)v, n, MEM_COMMIT, PAGE_READWRITE);
 	if(r != v)
 		runtime·throw("runtime: failed to commit pages");
 }
@@ -78,7 +78,7 @@ runtime·SysFree(void *v, uintptr n, uint64 *stat)
 	uintptr r;
 
 	runtime·xadd64(stat, -(uint64)n);
-	r = (uintptr)runtime·stdcall(runtime·VirtualFree, 3, v, (uintptr)0, (uintptr)MEM_RELEASE);
+	r = (uintptr)runtime·stdcall3(runtime·VirtualFree, (uintptr)v, 0, MEM_RELEASE);
 	if(r == 0)
 		runtime·throw("runtime: failed to release pages");
 }
@@ -96,12 +96,12 @@ runtime·SysReserve(void *v, uintptr n, bool *reserved)
 	*reserved = true;
 	// v is just a hint.
 	// First try at v.
-	v = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_RESERVE, (uintptr)PAGE_READWRITE);
+	v = runtime·stdcall4(runtime·VirtualAlloc, (uintptr)v, n, MEM_RESERVE, PAGE_READWRITE);
 	if(v != nil)
 		return v;
 	
 	// Next let the kernel choose the address.
-	return runtime·stdcall(runtime·VirtualAlloc, 4, nil, n, (uintptr)MEM_RESERVE, (uintptr)PAGE_READWRITE);
+	return runtime·stdcall4(runtime·VirtualAlloc, 0, n, MEM_RESERVE, PAGE_READWRITE);
 }
 
 void
@@ -112,7 +112,7 @@ runtime·SysMap(void *v, uintptr n, bool reserved, uint64 *stat)
 	USED(reserved);
 
 	runtime·xadd64(stat, n);
-	p = runtime·stdcall(runtime·VirtualAlloc, 4, v, n, (uintptr)MEM_COMMIT, (uintptr)PAGE_READWRITE);
+	p = runtime·stdcall4(runtime·VirtualAlloc, (uintptr)v, n, MEM_COMMIT, PAGE_READWRITE);
 	if(p != v)
 		runtime·throw("runtime: cannot map pages in arena address space");
 }

src/pkg/runtime/netpoll_windows.c

@@ -47,7 +47,7 @@ static uintptr iocphandle = INVALID_HANDLE_VALUE;  // completion port io handle
 void
 runtime·netpollinit(void)
 {
-	iocphandle = (uintptr)runtime·stdcall(runtime·CreateIoCompletionPort, 4, INVALID_HANDLE_VALUE, (uintptr)0, (uintptr)0, (uintptr)DWORD_MAX);
+	iocphandle = (uintptr)runtime·stdcall4(runtime·CreateIoCompletionPort, INVALID_HANDLE_VALUE, 0, 0, DWORD_MAX);
 	if(iocphandle == 0) {
 		runtime·printf("netpoll: failed to create iocp handle (errno=%d)\n", runtime·getlasterror());
 		runtime·throw("netpoll: failed to create iocp handle");
@@ -59,7 +59,7 @@ int32
 runtime·netpollopen(uintptr fd, PollDesc *pd)
 {
 	USED(pd);
-	if(runtime·stdcall(runtime·CreateIoCompletionPort, 4, fd, iocphandle, (uintptr)0, (uintptr)0) == 0)
+	if(runtime·stdcall4(runtime·CreateIoCompletionPort, fd, iocphandle, 0, 0) == 0)
 		return -runtime·getlasterror();
 	return 0;
 }
@@ -103,7 +103,7 @@ retry:
 			n = 8;
 		if(block)
 			g->m->blocked = true;
-		if(runtime·stdcall(runtime·GetQueuedCompletionStatusEx, 6, iocphandle, entries, (uintptr)n, &n, (uintptr)wait, (uintptr)0) == 0) {
+		if(runtime·stdcall6(runtime·GetQueuedCompletionStatusEx, iocphandle, (uintptr)entries, n, (uintptr)&n, wait, 0) == 0) {
 			g->m->blocked = false;
 			errno = runtime·getlasterror();
 			if(!block && errno == WAIT_TIMEOUT)
@@ -116,7 +116,7 @@ retry:
 			op = entries[i].op;
 			errno = 0;
 			qty = 0;
-			if(runtime·stdcall(runtime·WSAGetOverlappedResult, 5, runtime·netpollfd(op->pd), op, &qty, (uintptr)0, (uintptr)&flags) == 0)
+			if(runtime·stdcall5(runtime·WSAGetOverlappedResult, runtime·netpollfd(op->pd), (uintptr)op, (uintptr)&qty, 0, (uintptr)&flags) == 0)
 				errno = runtime·getlasterror();
 			handlecompletion(&gp, op, errno, qty);
 		}
@@ -126,7 +126,7 @@ retry:
 		qty = 0;
 		if(block)
 			g->m->blocked = true;
-		if(runtime·stdcall(runtime·GetQueuedCompletionStatus, 5, iocphandle, &qty, &key, &op, (uintptr)wait) == 0) {
+		if(runtime·stdcall5(runtime·GetQueuedCompletionStatus, iocphandle, (uintptr)&qty, (uintptr)&key, (uintptr)&op, wait) == 0) {
 			g->m->blocked = false;
 			errno = runtime·getlasterror();
 			if(!block && errno == WAIT_TIMEOUT)

src/pkg/runtime/os_windows.go

@@ -6,6 +6,17 @@ package runtime
 
 import "unsafe"
 
+type stdFunction *byte
+
+func stdcall0(fn stdFunction) uintptr
+func stdcall1(fn stdFunction, a0 uintptr) uintptr
+func stdcall2(fn stdFunction, a0, a1 uintptr) uintptr
+func stdcall3(fn stdFunction, a0, a1, a2 uintptr) uintptr
+func stdcall4(fn stdFunction, a0, a1, a2, a3 uintptr) uintptr
+func stdcall5(fn stdFunction, a0, a1, a2, a3, a4 uintptr) uintptr
+func stdcall6(fn stdFunction, a0, a1, a2, a3, a4, a5 uintptr) uintptr
+func stdcall7(fn stdFunction, a0, a1, a2, a3, a4, a5, a6 uintptr) uintptr
+
 func asmstdcall(fn unsafe.Pointer)
 func getlasterror() uint32
 func setlasterror(err uint32)

src/pkg/runtime/os_windows.h

@@ -8,11 +8,15 @@ extern void *runtime·GetQueuedCompletionStatusEx;
 
 // Call a Windows function with stdcall conventions,
 // and switch to os stack during the call.
-#pragma	varargck	countpos	runtime·stdcall	2
-#pragma	varargck	type		runtime·stdcall	void*
-#pragma	varargck	type		runtime·stdcall	uintptr
 void runtime·asmstdcall(void *c);
-void *runtime·stdcall(void *fn, int32 count, ...);
+void *runtime·stdcall0(void *fn);
+void *runtime·stdcall1(void *fn, uintptr a0);
+void *runtime·stdcall2(void *fn, uintptr a0, uintptr a1);
+void *runtime·stdcall3(void *fn, uintptr a0, uintptr a1, uintptr a2);
+void *runtime·stdcall4(void *fn, uintptr a0, uintptr a1, uintptr a2, uintptr a3);
+void *runtime·stdcall5(void *fn, uintptr a0, uintptr a1, uintptr a2, uintptr a3, uintptr a4);
+void *runtime·stdcall6(void *fn, uintptr a0, uintptr a1, uintptr a2, uintptr a3, uintptr a4, uintptr a5);
+void *runtime·stdcall7(void *fn, uintptr a0, uintptr a1, uintptr a2, uintptr a3, uintptr a4, uintptr a5, uintptr a6);
 
 uint32 runtime·getlasterror(void);
 void runtime·setlasterror(uint32 err);