gcc/libgo at 54bfc99b90e5986afbc2577964258265ea70e38d - gcc

History

Ian Lance Taylor 798c183f7f compiler, runtime: Fix unexpected GC interfering with closure passing. The Go frontend passes closures through to functions using the functions __go_set_closure and __go_get_closure. The expectation is that there are no function calls between set_closure and get_closure. However, it turns out that there can be function calls if some of the function arguments require type conversion to an interface type. Converting to an interface type can allocate memory, and that can in turn trigger a garbage collection, and that can in turn call pool cleanup functions that may call __go_set_closure. So the called function can see the wrong closure value, which is bad. This patch fixes the problem in two different ways. First, we move all type conversions in function arguments into temporary variables so that they can not appear before the call to __go_set_closure. (This required shifting the flatten phase after the simplify_thunk phase, since the latter expects to work with unconverted argument types.) Second, we fix the memory allocation function to preserve the closure value across any possible garbage collection. A test case is the libgo database/sql check run with the environment variable GOGC set to 1. From-SVN: r213932		2014-08-13 22:31:44 +00:00
..
config
go
runtime	compiler, runtime: Fix unexpected GC interfering with closure passing.	2014-08-13 22:31:44 +00:00
testsuite
aclocal.m4
config.h.in
configure
configure.ac
godeps.sh
LICENSE
Makefile.am
Makefile.in
MERGE
merge.sh
mksysinfo.sh
PATENTS
README
README.gcc

README

See ../README.

This is the runtime support library for the Go programming language.
This library is intended for use with the Go frontend.

The library has only been tested on GNU/Linux using glibc.  It should
not be difficult to port to other operating systems.

The library has only been tested on x86/x86_64 systems.  It should not
be difficult to port to other architectures.

Directories:

go
  A copy of the Go library from http://golang.org/, with a few
  changes for gccgo.  Notably, the reflection interface is different.

runtime
  Runtime functions, written in C, which are called directly by the
  compiler or by the library.

syscalls
  System call support.

Contributing
============

To contribute patches to the files in this directory, please see
http://golang.org/doc/gccgo_contribute.html .

The master copy of these files is hosted at
http://code.google.com/p/gofrontend .  Changes to these files require
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copyright holder, you will need to agree to the individual contributor
license agreement at
http://code.google.com/legal/individual-cla-v1.0.html.  This agreement
can be completed online.

If your organization is the copyright holder, the organization will
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http://code.google.com/legal/corporate-cla-v1.0.html.

If the copyright holder for your code has already completed the
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does not need to be completed again.