runtime: do not crash in lastcontinuehandler when running as DLL

If Go DLL is used by external C program, and lastcontinuehandler
is reached, lastcontinuehandler will crash the process it is
running in.

But it should not be up to Go runtime to decide if process to be
crashed or not - it should be up to C runtime. This CL adjusts
lastcontinuehandler to not to crash when running as DLL.

Fixes #32648.

Change-Id: Ia455e69b8dde2a6f42f06b90e8af4aa322ca269a
GitHub-Last-Rev: dbdffcb43206e94ef130ecadd1c82a8763225ac2
GitHub-Pull-Request: golang/go#32574
Reviewed-on: https://go-review.googlesource.com/c/go/+/181839
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/runtime/signal_windows.go b/src/runtime/signal_windows.go
index 3fc1ec5886..3b2c06b39c 100644
--- a/src/runtime/signal_windows.go
+++ b/src/runtime/signal_windows.go
@@ -171,6 +171,12 @@ var testingWER bool
 //
 //go:nosplit
 func lastcontinuehandler(info *exceptionrecord, r *context, gp *g) int32 {
+	if islibrary || isarchive {
+		// Go DLL/archive has been loaded in a non-go program.
+		// If the exception does not originate from go, the go runtime
+		// should not take responsibility of crashing the process.
+		return _EXCEPTION_CONTINUE_SEARCH
+	}
 	if testingWER {
 		return _EXCEPTION_CONTINUE_SEARCH
 	}