runtime: make StackSystem part of StackGuard
Fixes #1779
R=rsc
CC=golang-dev
https://golang.org/cl/4543052
diff --git a/src/pkg/runtime/stack.h b/src/pkg/runtime/stack.h
index ebf0462..2b6b0e3 100644
--- a/src/pkg/runtime/stack.h
+++ b/src/pkg/runtime/stack.h
@@ -53,6 +53,16 @@
*/
enum {
+ // StackSystem is a number of additional bytes to add
+ // to each stack below the usual guard area for OS-specific
+ // purposes like signal handling. Used on Windows because
+ // it does not use a separate stack.
+#ifdef __WINDOWS__
+ StackSystem = 2048,
+#else
+ StackSystem = 0,
+#endif
+
// The amount of extra stack to allocate beyond the size
// needed for the single frame that triggered the split.
StackExtra = 1024,
@@ -73,7 +83,7 @@
// The stack guard is a pointer this many bytes above the
// bottom of the stack.
- StackGuard = 256,
+ StackGuard = 256 + StackSystem,
// After a stack split check the SP is allowed to be this
// many bytes below the stack guard. This saves an instruction
@@ -82,5 +92,5 @@
// The maximum number of bytes that a chain of NOSPLIT
// functions can use.
- StackLimit = StackGuard - StackSmall,
+ StackLimit = StackGuard - StackSystem - StackSmall,
};
