diff options
Diffstat (limited to 'test/fixedbugs/issue29362b.go')
-rw-r--r-- | test/fixedbugs/issue29362b.go | 53 |
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) + } +} |