code review 6353055: doc/debugging_with_gdb: mention how to disable gc optim...

doc/debugging_with_gdb: mention how to disable gc optimization

[minux1, 2012-07-02 03:02:21]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go/

[r, 2012-07-02 22:09:44]

http://codereview.appspot.com/6353055/diff/1002/doc/debugging_with_gdb.html
File doc/debugging_with_gdb.html (right):

http://codereview.appspot.com/6353055/diff/1002/doc/debugging_with_gdb.html#n...
doc/debugging_with_gdb.html:31: </p>
The tone is wrong and the prose is a little misleading. How about

The code generated by the <code>gc</code> compiler includes inlining of function
invocation and registerization of variables.  These optimizations can sometimes
make debugging with <code>gdb</code> harder. To disable them when debugging,
pass the flags <code>-gcflags "-l -N"</code> to <code>go build</code>.

[r, 2012-07-02 22:10:22]

in my text, s/invocation/invocations/

[minux1, 2012-07-03 16:34:17]

PTAL.
On 2012/07/02 22:09:44, r wrote:
http://codereview.appspot.com/6353055/diff/1002/doc/debugging_with_gdb.html#n...
> doc/debugging_with_gdb.html:31: </p>
> The tone is wrong and the prose is a little misleading. How about
> 
> The code generated by the <code>gc</code> compiler includes inlining of
function
> invocation and registerization of variables.  These optimizations can
sometimes
> make debugging with <code>gdb</code> harder. To disable them when debugging,
> pass the flags <code>-gcflags "-l -N"</code> to <code>go build</code>.
I elaborated a little here, because these flags can also be applied to 'go test'
and 'go install'.

but then i realized a complication: if the user wants to debug the already
compiled
library, he must use 'go install -a -gcflags ...'; and after debugging, switch
off the gcflags and recompile the packages. maybe the go tool should remember
the flags used to compile the library, and automatically recompile when the
flags
changed (but to what extent does the recompilation occur? this is still a
problem),
the right solution should still be fixing the dwarf debugging info or perhaps a
go
specific debugger?).

[r, 2012-07-03 16:38:36]

http://codereview.appspot.com/6353055/diff/1004/doc/debugging_with_gdb.html
File doc/debugging_with_gdb.html (right):

http://codereview.appspot.com/6353055/diff/1004/doc/debugging_with_gdb.html#n...
doc/debugging_with_gdb.html:32: <code>go test</code>, <code>go install</code>
etc.).
s/.$/ used to build the code being debugged./

that should cover it. anyone competent enough to be comfortable using gdb and
special compiler flags shouldn't need more help than that.

[minux1, 2012-07-03 16:45:50]

Hello golang-dev@googlegroups.com, r@golang.org (cc:
golang-dev@googlegroups.com),

Please take another look.

[r, 2012-07-03 16:48:49]

LGTM after fixing the one grammar glitch.

http://codereview.appspot.com/6353055/diff/12002/doc/debugging_with_gdb.html
File doc/debugging_with_gdb.html (right):

http://codereview.appspot.com/6353055/diff/12002/doc/debugging_with_gdb.html#...
doc/debugging_with_gdb.html:28: functions invocations and registerization of
variables. These optimizations
s/functions/function/

[minux1, 2012-07-03 16:50:05]

*** Submitted as http://code.google.com/p/go/source/detail?r=be7e338a8960 ***

doc/debugging_with_gdb: mention how to disable gc optimization

R=golang-dev, r
CC=golang-dev
http://codereview.appspot.com/6353055