NaCl docs: update computed goto support

NaCl docs: update computed goto support

mseaborn added computed goto lowering in:
https://codereview.chromium.org/120773002

R= binji@chromium.org, sbc@chromium.org, mseaborn@chromium.org
TEST=none
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3695
NOTRY=true
(documentation only change)

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254570

[Mark Seaborn, 2014-03-03 20:41:02]

"error: old chunk mismatch".  Rietveld sucks.  Please re-upload.

[JF, 2014-03-03 20:47:07]

On 2014/03/03 20:41:02, Mark Seaborn wrote:
> "error: old chunk mismatch".  Rietveld sucks.  Please re-upload.

Ugh, sorry about that... Should be fixed now.

[binji, 2014-03-03 21:18:54]

lgtm

[Mark Seaborn, 2014-03-03 21:23:04]

https://codereview.chromium.org/185653007/diff/20001/native_client_sdk/src/do...
File native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst
(right):

https://codereview.chromium.org/185653007/diff/20001/native_client_sdk/src/do...
native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst:231: PNaCl
supports computed ``goto``, a non-standard extension to C used by
You could be more specific and say "GCC extension".

ExpandIndirectBr.cpp has this extra advice that would be useful to put in the
docs:

// The resulting use of switches might not be as fast as the original
// indirectbrs.  If you are compiling a program that has a
// compile-time option for using computed gotos, it's possible that
// the program will run faster with the option turned off than with
// using computed gotos + ExpandIndirectBr (for example, if the
// program does extra work to take advantage of computed gotos).

[JF, 2014-03-03 21:30:32]

https://codereview.chromium.org/185653007/diff/20001/native_client_sdk/src/do...
File native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst
(right):

https://codereview.chromium.org/185653007/diff/20001/native_client_sdk/src/do...
native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst:231: PNaCl
supports computed ``goto``, a non-standard extension to C used by
On 2014/03/03 21:23:04, Mark Seaborn wrote:
> You could be more specific and say "GCC extension".
> 
> ExpandIndirectBr.cpp has this extra advice that would be useful to put in the
> docs:
> 
> // The resulting use of switches might not be as fast as the original
> // indirectbrs.  If you are compiling a program that has a
> // compile-time option for using computed gotos, it's possible that
> // the program will run faster with the option turned off than with
> // using computed gotos + ExpandIndirectBr (for example, if the
> // program does extra work to take advantage of computed gotos).

That's helpful, I added it. Thanks!

[Mark Seaborn, 2014-03-03 21:33:39]

LGTM

[JF, 2014-03-03 21:42:33]

The CQ bit was checked by jfb@chromium.org

[commit-bot: I haz the power, 2014-03-03 21:43:50]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jfb@chromium.org/185653007/40001

[commit-bot: I haz the power, 2014-03-03 21:45:38]

Change committed as 254570