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-rw-r--r--test/fixedbugs/issue29362b.go53
1 files changed, 53 insertions, 0 deletions
diff --git a/test/fixedbugs/issue29362b.go b/test/fixedbugs/issue29362b.go
new file mode 100644
index 0000000..d1e3b47
--- /dev/null
+++ b/test/fixedbugs/issue29362b.go
@@ -0,0 +1,53 @@
+// run
+
+// Copyright 2018 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.
+
+// Verify that we don't consider a Go'd function's
+// arguments as pointers when they aren't.
+
+package main
+
+import (
+ "unsafe"
+)
+
+var badPtr uintptr
+
+var sink []byte
+
+func init() {
+ // Allocate large enough to use largeAlloc.
+ b := make([]byte, 1<<16-1)
+ sink = b // force heap allocation
+ // Any space between the object and the end of page is invalid to point to.
+ badPtr = uintptr(unsafe.Pointer(&b[len(b)-1])) + 1
+}
+
+var throttle = make(chan struct{}, 10)
+
+// There are 2 arg bitmaps for this function, each with 2 bits.
+// In the first, p and q are both live, so that bitmap is 11.
+// In the second, only p is live, so that bitmap is 10.
+// Bitmaps are byte aligned, so if the first bitmap is interpreted as
+// extending across the entire argument area, we incorrectly concatenate
+// the bitmaps and end up using 110000001. That bad bitmap causes a6
+// to be considered a pointer.
+func noPointerArgs(p, q *byte, a0, a1, a2, a3, a4, a5, a6 uintptr) {
+ sink = make([]byte, 4096)
+ sinkptr = q
+ <-throttle
+ sinkptr = p
+}
+
+var sinkptr *byte
+
+func main() {
+ const N = 1000
+ for i := 0; i < N; i++ {
+ throttle <- struct{}{}
+ go noPointerArgs(nil, nil, badPtr, badPtr, badPtr, badPtr, badPtr, badPtr, badPtr)
+ sink = make([]byte, 4096)
+ }
+}