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> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only. Please ask questions on https://forum.golangbridge.org or https://groups.google.com/forum/#!forum/golang-nuts.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
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Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.
