5l, 8l: pass stack frame size to morestack when needed

Shame on me: I fixed the same bug in 6l in 8691fcc6a66e
(https://golang.org/cl/2609041) and neglected
to look at 5l and 8l to see if they were affected.

On the positive side, the check I added in that CL is the
one that detected this bug.

Fixes #1457.

R=ken2
CC=golang-dev
https://golang.org/cl/3981052

1 files changed, 27 insertions, 0 deletions

diff --git a/test/stack.go b/test/stack.go
index 816b555a4c..1fd57161ff 100644
--- a/test/stack.go
+++ b/test/stack.go
@@ -30,6 +30,32 @@ func d(t T) {
 	}
 }
 
+func f0() {
+	// likely to make a new stack for f0,
+	// because the call to f1 puts 3000 bytes
+	// in our frame.
+	f1()
+}
+
+func f1() [3000]byte {
+	// likely to make a new stack for f1,
+	// because 3000 bytes were used by f0
+	// and we need 3000 more for the call
+	// to f2.  if the call to morestack in f1
+	// does not pass the frame size, the new
+	// stack (default size 5k) will not be big
+	// enough for the frame, and the morestack
+	// check in f2 will die, if we get that far 
+	// without faulting.
+	f2()
+	return [3000]byte{}
+}
+
+func f2() [3000]byte {
+	// just take up space
+	return [3000]byte{}
+}
+
 var c = make(chan int)
 var t T
 var b = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
@@ -40,6 +66,7 @@ func recur(n int) {
 		panic("bad []byte -> string")
 	}
 	go g(c, t)
+	f0()
 	s := <-c
 	if s != len(t) {
 		println("bad go", s)