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https://github.com/golang/go
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0c1f0549b8
The memory sanitizer (msan) is a nice compiler feature that can dynamically check for memory errors in C code. It's not useful for Go code, since Go is memory safe. But it is useful to be able to use the memory sanitizer on C code that is linked into a Go program via cgo. Without this change it does not work, as msan considers memory passed from Go to C as uninitialized. To make this work, change the runtime to call the C mmap function when using cgo. When using msan the mmap call will be intercepted and marked as returning initialized memory. Work around what appears to be an msan bug by calling malloc before we call mmap. Change-Id: I8ab7286d7595ae84782f68a98bef6d3688b946f9 Reviewed-on: https://go-review.googlesource.com/15170 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
23 lines
733 B
Go
23 lines
733 B
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build linux,amd64
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package cgo
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// Import "unsafe" because we use go:linkname.
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import _ "unsafe"
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// When using cgo, call the C library for mmap, so that we call into
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// any sanitizer interceptors. This supports using the memory
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// sanitizer with Go programs. The memory sanitizer only applies to
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// C/C++ code; this permits that code to see the Go code as normal
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// program addresses that have been initialized.
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//go:cgo_import_static x_cgo_mmap
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//go:linkname x_cgo_mmap x_cgo_mmap
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//go:linkname _cgo_mmap _cgo_mmap
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var x_cgo_mmap byte
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var _cgo_mmap = &x_cgo_mmap
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