mirror of
https://gcc.gnu.org/git/gcc.git
synced 2024-12-05 09:44:10 +08:00
f1857c6369
When C code calls a Go function, it actually calls a function generated by cgo. That function is written in Go, and, among other things, it calls the real Go function like this: CgocallBack() defer CgocallBackDone() RealGoFunction() The deferred CgocallBackDone function enters syscall mode as we return to C. Typically the C function will then eventually return to Go. However, in the case where the C function is running on a thread created in C, it will not return to Go. For that case we will have allocated an m struct, with an associated g struct, for the duration of the Go code, and when the Go is complete we will return the m and g to a free list. That all works, but we are running in a deferred function, which means that we have been invoked by deferreturn, and deferreturn expects to do a bit of cleanup to record that the defer has been completed. Doing that cleanup while using an m and g that have already been returned to the free list is clearly a bad idea. It was kind of working because deferreturn was holding the g pointer in a local variable, but there were races with some other thread picking up and using the newly freed g. It was also kind of working because of a special check in freedefer; that check is no longer necessary. This patch changes the special case of releasing the m and g to do the defer cleanup in CgocallBackDone itself. This patch also checks for the special case of a panic through CgocallBackDone. In that special case, we don't want to release the m and g. Since we are returning to C code that was not called by Go code, we know that the panic is not going to be caught and we are going to exit the program. So for that special case we keep the m and g structs so that the rest of the panic code can use them. Reviewed-on: https://go-review.googlesource.com/46530 From-SVN: r249611 |
||
---|---|---|
.. | ||
config | ||
go | ||
runtime | ||
testsuite | ||
aclocal.m4 | ||
config.h.in | ||
configure | ||
configure.ac | ||
godeps.sh | ||
libgo.imp | ||
LICENSE | ||
Makefile.am | ||
Makefile.in | ||
match.sh | ||
MERGE | ||
merge.sh | ||
mkrsysinfo.sh | ||
mksigtab.sh | ||
mksysinfo.sh | ||
mvifdiff.sh | ||
PATENTS | ||
README | ||
README.gcc | ||
sysinfo.c | ||
VERSION |
See ../README. This is the runtime support library for the Go programming language. This library is intended for use with the Go frontend. This library should not be stripped when it is installed. Go code relies on being able to look up file/line information, which comes from the debugging info using the libbacktrace library. The library has only been tested on GNU/Linux using glibc, and on Solaris. It should not be difficult to port to other operating systems. Directories: go A copy of the Go library from http://golang.org/, with several changes for gccgo. runtime Runtime functions, written in C, which are called directly by the compiler or by the library. 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 signing a Google contributor license agreement. If you are the 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 need to agree to the corporate contributor license agreement at http://code.google.com/legal/corporate-cla-v1.0.html. If the copyright holder for your code has already completed the agreement in connection with another Google open source project, it does not need to be completed again.