1
0
mirror of https://github.com/golang/go synced 2024-11-12 09:50:21 -07:00
The Go programming language
Go to file
Russ Cox b377c9c6a9 liblink, runtime: fix cgo on arm
The addition of TLS to ARM rewrote the MRC instruction
differently depending on whether we were using internal
or external linking mode. That's clearly not okay, since we
don't know that during compilation, which is when we now
generate the code. Also, because the change did not introduce
a real MRC instruction but instead just macro-expanded it
in the assembler, liblink is rewriting a WORD instruction that
may actually be looking for that specific constant, which would
lead to very unexpected results. It was also using one value
that happened to be 8 where a different value that also
happened to be 8 belonged. So the code was correct for those
values but not correct in general, and very confusing.

Throw it all away.

Replace with the following. There is a linker-provided symbol
runtime.tlsgm with a value (address) set to the offset from the
hardware-provided TLS base register to the g and m storage.
Any reference to that name emits an appropriate TLS relocation
to be resolved by either the internal linker or the external linker,
depending on the link mode. The relocation has exactly the
semantics of the R_ARM_TLS_LE32 relocation, which is what
the external linker provides.

This symbol is only used in two routines, runtime.load_gm and
runtime.save_gm. In both cases it is now used like this:

        MRC		15, 0, R0, C13, C0, 3 // fetch TLS base pointer
        MOVW	$runtime·tlsgm(SB), R2
        ADD	R2, R0 // now R0 points at thread-local g+m storage

It is likely that this change breaks the generation of shared libraries
on ARM, because the MOVW needs to be rewritten to use the global
offset table and a different relocation type. But let's get the supported
functionality working again before we worry about unsupported
functionality.

LGTM=dave, iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/56120043
2014-01-23 22:51:39 -05:00
api api: update next.txt 2014-01-22 10:54:51 -08:00
doc effective_go: move 'Type switch' section into 'Control structures' section. 2014-01-23 16:26:42 -08:00
include liblink: include missing pragmas for plan9 formatter 2014-01-22 06:23:19 +01:00
lib lib/codereview: add LGTM= line to commit messages 2014-01-23 15:10:38 -05:00
misc misc/cgo/testtls: make test less flaky 2014-01-21 19:44:51 -05:00
src liblink, runtime: fix cgo on arm 2014-01-23 22:51:39 -05:00
test cmd/gc: preserve qualified names of unexported methods in imports. 2014-01-21 22:55:50 -05:00
.hgignore .hgignore: remove duplicate entry 2013-12-12 19:01:50 -08:00
.hgtags tag go1.2 2013-12-02 09:06:41 +11:00
AUTHORS A+C: Maxim Khitrov (individual CLA) 2014-01-17 11:26:42 -05:00
CONTRIBUTORS A+C: Maxim Khitrov (individual CLA) 2014-01-17 11:26:42 -05:00
favicon.ico godoc: update favicon 2012-10-11 17:02:36 +11:00
LICENSE
PATENTS
README README: Fix installation instructions 2013-11-20 13:47:37 -08:00
robots.txt

This is the source code repository for the Go programming language.  

For documentation about how to install and use Go,
visit http://golang.org/ or load doc/install-source.html
in your web browser.

After installing Go, you can view a nicely formatted
doc/install-source.html by running godoc --http=:6060
and then visiting http://localhost:6060/doc/install/source.

Unless otherwise noted, the Go source files are distributed
under the BSD-style license found in the LICENSE file.

--

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 README).  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.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 doc/install.html for more details.