runtime: convert NewCallback and NewCallbackCDecl to Go

LGTM=khr
R=khr, remyoudompheng
CC=golang-codereviews
https://golang.org/cl/132820043

src/cmd/api/goapi.go

@@ -384,8 +384,9 @@ func (w *Walker) parseFile(dir, file string) (*ast.File, error) {
 			" iface struct{}; eface struct{}; interfacetype struct{}; itab struct{};" +
 			" mcache struct{}; bucket struct{}; sudog struct{}; g struct{};" +
 			" hchan struct{}; chantype struct{}; waitq struct{};" +
-			" note struct{};" +
-			")"
+			" note struct{}; wincallbackcontext struct{};" +
+			"); " +
+			"const ( cb_max = 2000 )"
 		f, err = parser.ParseFile(fset, filename, src, 0)
 		if err != nil {
 			log.Fatalf("incorrect generated file: %s", err)

src/cmd/dist/buildruntime.c

@@ -403,6 +403,11 @@ mkzruntimedefs(char *dir, char *file)
 		bwritestr(&out, p);
 	}
 
+	// Some windows specific const.
+	if(streq(goos, "windows")) {
+		bwritestr(&out, bprintf(&b, "const cb_max = %d\n", MAXWINCB));
+	}
+	
 	writefile(&out, file, 0);
 
 	bfree(&in);

src/pkg/runtime/callback_windows.c

-// Copyright 2009 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.
-
-#include "runtime.h"
-#include "type.h"
-#include "typekind.h"
-#include "defs_GOOS_GOARCH.h"
-#include "os_GOOS.h"
-#include "zasm_GOOS_GOARCH.h"
-
-typedef	struct	Callbacks	Callbacks;
-struct	Callbacks {
-	Lock			lock;
-	WinCallbackContext*	ctxt[cb_max];
-	int32			n;
-};
-
-static	Callbacks	cbs;
-
-WinCallbackContext** runtime·cbctxts; // to simplify access to cbs.ctxt in sys_windows_*.s
-
-// Call back from windows dll into go.
-byte *
-runtime·compilecallback(Eface fn, bool cleanstack)
-{
-	FuncType *ft;
-	Type *t;
-	int32 argsize, i, n;
-	WinCallbackContext *c;
-
-	if(fn.type == nil || (fn.type->kind&KindMask) != KindFunc)
-		runtime·panicstring("compilecallback: not a function");
-	ft = (FuncType*)fn.type;
-	if(ft->out.len != 1)
-		runtime·panicstring("compilecallback: function must have one output parameter");
-	if(((Type**)ft->out.array)[0]->size != sizeof(uintptr))
-		runtime·panicstring("compilecallback: output parameter size is wrong");
-	argsize = 0;
-	for(i=0; i<ft->in.len; i++) {
-		t = ((Type**)ft->in.array)[i];
-		if(t->size > sizeof(uintptr))
-			runtime·panicstring("compilecallback: input parameter size is wrong");
-		argsize += sizeof(uintptr);
-	}
-
-	runtime·lock(&cbs.lock);
-	if(runtime·cbctxts == nil)
-		runtime·cbctxts = &(cbs.ctxt[0]);
-	n = cbs.n;
-	for(i=0; i<n; i++) {
-		if(cbs.ctxt[i]->gobody == fn.data && cbs.ctxt[i]->cleanstack == cleanstack) {
-			runtime·unlock(&cbs.lock);
-			// runtime·callbackasm is just a series of CALL instructions
-			// (each is 5 bytes long), and we want callback to arrive at
-			// correspondent call instruction instead of start of
-			// runtime·callbackasm.
-			return (byte*)runtime·callbackasm + i * 5;
-		}
-	}
-	if(n >= cb_max)
-		runtime·throw("too many callback functions");
-	c = runtime·mallocgc(sizeof *c, nil, 0);
-	c->gobody = fn.data;
-	c->argsize = argsize;
-	c->cleanstack = cleanstack;
-	if(cleanstack && argsize!=0)
-		c->restorestack = argsize;
-	else
-		c->restorestack = 0;
-	cbs.ctxt[n] = c;
-	cbs.n++;
-	runtime·unlock(&cbs.lock);
-
-	// as before
-	return (byte*)runtime·callbackasm + n * 5;
-}

src/pkg/runtime/syscall_windows.go

+// 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 (
+	"unsafe"
+)
+
+type callbacks struct {
+	lock
+	ctxt [cb_max]*wincallbackcontext
+	n    int
+}
+
+func (c *wincallbackcontext) isCleanstack() bool {
+	return c.cleanstack == 1
+}
+
+func (c *wincallbackcontext) setCleanstack(cleanstack bool) {
+	if cleanstack {
+		c.cleanstack = 1
+	} else {
+		c.cleanstack = 0
+	}
+}
+
+var (
+	cbs     callbacks
+	cbctxts **wincallbackcontext = &cbs.ctxt[0] // to simplify access to cbs.ctxt in sys_windows_*.s
+
+	callbackasm byte // type isn't really byte, it's code in runtime
+)
+
+// callbackasmAddr returns address of runtime.callbackasm
+// function adjusted by i.
+// runtime.callbackasm is just a series of CALL instructions
+// (each is 5 bytes long), and we want callback to arrive at
+// correspondent call instruction instead of start of
+// runtime.callbackasm.
+func callbackasmAddr(i int) uintptr {
+	return uintptr(add(unsafe.Pointer(&callbackasm), uintptr(i*5)))
+}
+
+func compileCallback(fn eface, cleanstack bool) (code uintptr) {
+	if fn._type == nil || (fn._type.kind&kindMask) != kindFunc {
+		panic("compilecallback: not a function")
+	}
+	ft := (*functype)(unsafe.Pointer(fn._type))
+	if len(ft.out) != 1 {
+		panic("compilecallback: function must have one output parameter")
+	}
+	uintptrSize := uint(unsafe.Sizeof(uintptr(0)))
+	if t := (**_type)(unsafe.Pointer(&ft.out[0])); (*t).size != uintptrSize {
+		panic("compilecallback: output parameter size is wrong")
+	}
+	argsize := uint(0)
+	for _, t := range (*[1024](*_type))(unsafe.Pointer(&ft.in[0]))[:len(ft.in)] {
+		if (*t).size != uintptrSize {
+			panic("compilecallback: input parameter size is wrong")
+		}
+		argsize += uintptrSize
+	}
+
+	golock(&cbs.lock)
+	defer gounlock(&cbs.lock)
+
+	n := cbs.n
+	for i := 0; i < n; i++ {
+		if cbs.ctxt[i].gobody == fn.data && cbs.ctxt[i].isCleanstack() == cleanstack {
+			return callbackasmAddr(i)
+		}
+	}
+	if n >= cb_max {
+		gothrow("too many callback functions")
+	}
+
+	c := new(wincallbackcontext)
+	c.gobody = fn.data
+	c.argsize = argsize
+	c.setCleanstack(cleanstack)
+	if cleanstack && argsize != 0 {
+		c.restorestack = argsize
+	} else {
+		c.restorestack = 0
+	}
+	cbs.ctxt[n] = c
+	cbs.n++
+
+	return callbackasmAddr(n)
+}

src/pkg/runtime/syscall_windows.goc

@@ -36,14 +36,6 @@ func getprocaddress(handle uintptr, procname *uint8) (proc uintptr, err uintptr)
 		err = 0;
 }
 
-func NewCallback(fn Eface) (code uintptr) {
-	code = (uintptr)runtime·compilecallback(fn, true);
-}
-
-func NewCallbackCDecl(fn Eface) (code uintptr) {
-	code = (uintptr)runtime·compilecallback(fn, false);
-}
-
 func Syscall(fn uintptr, nargs uintptr, a1 uintptr, a2 uintptr, a3 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
 	LibCall c;
 

src/pkg/syscall/asm_windows_386.s → src/pkg/syscall/asm_windows.s

@@ -3,5 +3,11 @@
 // license that can be found in the LICENSE file.
 
 //
-// System calls for 386, Windows are implemented in ../runtime/syscall_windows.goc
+// System calls for Windows are implemented in ../runtime/syscall_windows.goc
 //
+
+#include "textflag.h"
+
+// func compileCallback(fn interface{}, cleanstack bool) uintptr
+TEXT ·compileCallback(SB),NOSPLIT,$0
+	JMP	runtime·compileCallback(SB)

src/pkg/syscall/asm_windows_amd64.s

-// Copyright 2009 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.
-
-//
-// System calls for amd64, Windows are implemented in ../runtime/syscall_windows.goc
-//

src/pkg/syscall/syscall_windows.go

@@ -105,12 +105,22 @@ func (e Errno) Timeout() bool {
 	return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
 }
 
+// Implemented in asm_windows.s
+func compileCallback(fn interface{}, cleanstack bool) uintptr
+
+// Converts a Go function to a function pointer conforming
+// to the stdcall calling convention. This is useful when
+// interoperating with Windows code requiring callbacks.
+func NewCallback(fn interface{}) uintptr {
+	return compileCallback(fn, true)
+}
+
 // Converts a Go function to a function pointer conforming
-// to the stdcall or cdecl calling convention.  This is useful when
+// to the cdecl calling convention. This is useful when
 // interoperating with Windows code requiring callbacks.
-// Implemented in ../runtime/syscall_windows.goc
-func NewCallback(fn interface{}) uintptr
-func NewCallbackCDecl(fn interface{}) uintptr
+func NewCallbackCDecl(fn interface{}) uintptr {
+	return compileCallback(fn, false)
+}
 
 // windows api calls