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a16954b8a7
The pointer checking code needs to know the exact type of the parameter expected by the C function, so that it can use a type assertion to convert the empty interface returned by cgoCheckPointer to the correct type. Previously this was done by using a type conversion, but that meant that the code accepted arguments that were convertible to the parameter type, rather than arguments that were assignable as in a normal function call. In other words, some code that should not have passed type checking was accepted. This CL changes cgo to always use a function literal for pointer checking. Now the argument is passed to the function literal, which has the correct argument type, so type checking is performed just as for a function call as it should be. Since we now always use a function literal, simplify the checking code to run as a statement by itself. It now no longer needs to return a value, and we no longer need a type assertion. This does have the cost of introducing another function call into any call to a C function that requires pointer checking, but the cost of the additional call should be minimal compared to the cost of pointer checking. Fixes #16591. Change-Id: I220165564cf69db9fd5f746532d7f977a5b2c989 Reviewed-on: https://go-review.googlesource.com/31233 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
18 lines
385 B
Go
18 lines
385 B
Go
// Copyright 2016 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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// Issue 16591: Test that we detect an invalid call that was being
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// hidden by a type conversion inserted by cgo checking.
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package p
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// void f(int** p) { }
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import "C"
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type x *C.int
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func F(p *x) {
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C.f(p) // ERROR HERE
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}
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