runtime: handle windows exceptions, even in cgo programs

Fixes #3543. R=golang-dev, kardianos, rsc CC=golang-dev, hectorchu, vcc.163 https://golang.org/cl/6245063

Author: alexbrainman

src/cmd/dist/buildruntime.c

@@ -227,6 +227,8 @@ mkzasm(char *dir, char *file)
 aggr = "gobuf";
 else if(streq(fields.p[1], "WinCall"))
 aggr = "wincall";
+else if(streq(fields.p[1], "SEH"))
+aggr = "seh";
 }
 if(hasprefix(lines.p[i], "}"))
 aggr = nil;

src/pkg/runtime/crash_cgo_test.go

@@ -0,0 +1,15 @@
+// Copyright 2012 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.
+
+// +build cgo
+
+package runtime_test
+
+import (
+"testing"
+)
+
+func TestCgoCrashHandler(t *testing.T) {
+testCrashHandler(t, &crashTest{Cgo: true})
+}

src/pkg/runtime/crash_test.go

@@ -0,0 +1,100 @@
+// Copyright 2012 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_test
+
+import (
+"io/ioutil"
+"os"
+"os/exec"
+"path/filepath"
+"testing"
+"text/template"
+)
+
+type crashTest struct {
+Cgo bool
+}
+
+// This test is a separate program, because it is testing
+// both main (m0) and non-main threads (m).
+
+func testCrashHandler(t *testing.T, ct *crashTest) {
+st := template.Must(template.New("crashSource").Parse(crashSource))
+
+dir, err := ioutil.TempDir("", "go-build")
+if err != nil {
+t.Fatalf("failed to create temp directory: %v", err)
+}
+defer os.RemoveAll(dir)
+
+src := filepath.Join(dir, "main.go")
+f, err := os.Create(src)
+if err != nil {
+t.Fatalf("failed to create %v: %v", src, err)
+}
+err = st.Execute(f, ct)
+if err != nil {
+f.Close()
+t.Fatalf("failed to execute template: %v", err)
+}
+f.Close()
+
+got, err := exec.Command("go", "run", src).CombinedOutput()
+if err != nil {
+t.Fatalf("program exited with error: %v\n%v", err, string(got))
+}
+want := "main: recovered done\nnew-thread: recovered done\nsecond-new-thread: recovered done\nmain-again: recovered done\n"
+if string(got) != string(want) {
+t.Fatalf("expected %q, but got %q", string(want), string(got))
+}
+}
+
+func TestCrashHandler(t *testing.T) {
+testCrashHandler(t, &crashTest{Cgo: false})
+}
+
+const crashSource = `
+package main
+
+import (
+"fmt"
+"runtime"
+)
+
+{{if .Cgo}}
+import "C"
+{{end}}
+
+func test(name string) {
+defer func() {
+if x := recover(); x != nil {
+fmt.Printf(" recovered")
+}
+fmt.Printf(" done\n")
+}()
+fmt.Printf("%s:", name)
+var s *string
+_ = *s
+fmt.Print("SHOULD NOT BE HERE")
+}
+
+func testInNewThread(name string) {
+c := make(chan bool)
+go func() {
+runtime.LockOSThread()
+test(name)
+c <- true
+}()
+<-c
+}
+
+func main() {
+runtime.LockOSThread()
+test("main")
+testInNewThread("new-thread")
+testInNewThread("second-new-thread")
+test("main-again")
+}
+`

src/pkg/runtime/os_windows.h

@@ -28,5 +28,7 @@ uint32 runtime·ctrlhandler(uint32 type);
 byte *runtime·compilecallback(Eface fn, bool cleanstack);
 void *runtime·callbackasm(void);
 
+void runtime·install_exception_handler(void);
+
 // TODO(brainman): should not need those
 #defineNSIG65

src/pkg/runtime/proc.c

@@ -758,6 +758,11 @@ runtime·starttheworld(void)
 void
 runtime·mstart(void)
 {
+// It is used by windows-386 only. Unfortunately, seh needs
+// to be located on os stack, and mstart runs on os stack
+// for both m0 and m.
+SEH seh;
+
 if(g != m->g0)
 runtime·throw("bad runtime·mstart");
 
@@ -766,6 +771,7 @@ runtime·mstart(void)
 // so other calls can reuse this stack space.
 runtime·gosave(&m->g0->sched);
 m->g0->sched.pc = (void*)-1; // make sure it is never used
+m->seh = &seh;
 runtime·asminit();
 runtime·minit();
 
@@ -775,6 +781,10 @@ runtime·mstart(void)
 runtime·initsig();
 
 schedule(nil);
+
+// TODO(brainman): This point is never reached, because scheduler
+// does not release os threads at the moment. But once this path
+// is enabled, we must remove our seh here.
 }
 
 // When running with cgo, we call libcgo_thread_start

src/pkg/runtime/rt0_windows_386.s

@@ -3,11 +3,6 @@
 // license that can be found in the LICENSE file.
 
 TEXT _rt0_386_windows(SB),7,$0
-// Set up SEH frame for bootstrap m
-PUSHL$runtime·sigtramp(SB)
-PUSHL0(FS)
-MOVLSP, 0(FS)
-
 JMP_rt0_386(SB)
 
 DATA runtime·iswindows(SB)/4, $1

src/pkg/runtime/runtime.h

@@ -69,6 +69,7 @@ typedef	struct	Hchan	Hchan;
 typedefstructComplex64Complex64;
 typedefstructComplex128Complex128;
 typedefstructWinCallWinCall;
+typedefstructSEHSEH;
 typedefstructTimersTimers;
 typedefstructTimerTimer;
 typedef structGCStatsGCStats;
@@ -262,6 +263,7 @@ struct	M
 #ifdef GOOS_windows
 void*thread;// thread handle
 #endif
+SEH*seh;
 uintptrend[];
 };
 
@@ -316,6 +318,11 @@ struct	WinCall
 uintptrr2;
 uintptrerr;// error number
 };
+structSEH
+{
+void*prev;
+void*handler;
+};
 
 #ifdef GOOS_windows
 enum {

src/pkg/runtime/sys_windows_386.s

@@ -243,11 +243,6 @@ TEXT runtime·tstart(SB),7,$0
 MOVLnewm+4(SP), CX// m
 MOVLm_g0(CX), DX// g
 
-// Set up SEH frame
-PUSHL$runtime·sigtramp(SB)
-PUSHL0(FS)
-MOVLSP, 0(FS)
-
 // Layout new m scheduler stack on os stack.
 MOVLSP, AX
 MOVLAX, g_stackbase(DX)
@@ -267,11 +262,6 @@ TEXT runtime·tstart(SB),7,$0
 
 CALLruntime·mstart(SB)
 
-// Pop SEH frame
-MOVL0(FS), SP
-POPL0(FS)
-POPLCX
-
 RET
 
 // uint32 tstart_stdcall(M *newm);
@@ -296,3 +286,20 @@ TEXT runtime·setldt(SB),7,$0
 MOVLaddress+4(FP), CX
 MOVLCX, 0x14(FS)
 RET
+
+// void install_exception_handler()
+TEXT runtime·install_exception_handler(SB),7,$0
+get_tls(CX)
+MOVLm(CX), CX// m
+
+// Set up SEH frame
+MOVLm_seh(CX), DX
+MOVL$runtime·sigtramp(SB), AX
+MOVLAX, seh_handler(DX)
+MOVL0(FS), AX
+MOVLAX, seh_prev(DX)
+
+// Install it
+MOVLDX, 0(FS)
+
+RET

src/pkg/runtime/sys_windows_amd64.s

@@ -328,7 +328,6 @@ TEXT runtime·tstart_stdcall(SB),7,$0
 // Someday the convention will be D is always cleared.
 CLD
 
-CALLruntime·setstacklimits(SB)
 CALLruntime·stackcheck(SB)// clobbers AX,CX
 CALLruntime·mstart(SB)
 
@@ -337,6 +336,10 @@ TEXT runtime·tstart_stdcall(SB),7,$0
 
 // set tls base to DI
 TEXT runtime·settls(SB),7,$0
-CALLruntime·setstacklimits(SB)
 MOVQDI, 0x28(GS)
 RET
+
+// void install_exception_handler()
+TEXT runtime·install_exception_handler(SB),7,$0
+CALLruntime·setstacklimits(SB)
+RET

src/pkg/runtime/thread_windows.c

@@ -208,6 +208,7 @@ runtime·newosproc(M *m, G *g, void *stk, void (*fn)(void))
 void
 runtime·minit(void)
 {
+runtime·install_exception_handler();
 }
 
 int64