[prof] export slide offset in profile log

[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=

Committed: https://crrev.com/aee17a63b3b83753b271b01409459e538fa1822f
Cr-Commit-Position: refs/heads/master@{#35921}

[fedor.indutny, 2016-04-29 18:47:25]

Description was changed from

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=
==========

to

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=
==========

[fedor.indutny, 2016-04-29 18:47:25]

fedor@indutny.com changed reviewers:
+ jochen@chromium.org

[fedor.indutny, 2016-04-29 18:47:35]

Added a reviewer.

[jochen (gone - plz use gerrit), 2016-04-29 18:51:46]

jochen@chromium.org changed reviewers:
+ jarin@chromium.org, yangguo@chromium.org

[jochen (gone - plz use gerrit), 2016-04-29 18:51:47]

+better reviewers for this

[noordhuis, 2016-04-30 10:37:09]

info@bnoordhuis.nl changed reviewers:
+ info@bnoordhuis.nl

[noordhuis, 2016-04-30 10:37:10]

https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform.h
File src/base/platform/platform.h (right):

https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform....
src/base/platform/platform.h:244: : library_path(library_path), start(start),
end(end), slide(slide) {}
I think this should use intptr_t for the slide because it can be negative; text
sections can be mapped before their default load addresses.  Because of
signed-to-unsigned conversion, logging such slides and adding them to function
addresses in tickprocessor.js, produces bogus results.

intptr_t is what _dyld_get_image_vmaddr_slide() returns.  platform-macos.cc
currently gets this wrong, FWIW.

[fedor.indutny, 2016-04-30 19:54:51]

https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform.h
File src/base/platform/platform.h (right):

https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform....
src/base/platform/platform.h:244: : library_path(library_path), start(start),
end(end), slide(slide) {}
On 2016/04/30 10:37:10, noordhuis wrote:
> I think this should use intptr_t for the slide because it can be negative;
text
> sections can be mapped before their default load addresses.  Because of
> signed-to-unsigned conversion, logging such slides and adding them to function
> addresses in tickprocessor.js, produces bogus results.
> 
> intptr_t is what _dyld_get_image_vmaddr_slide() returns.  platform-macos.cc
> currently gets this wrong, FWIW.

Acknowledged.

[Yang, 2016-05-02 06:39:43]

On 2016/04/30 19:54:51, fedor.indutny wrote:
> https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform.h
> File src/base/platform/platform.h (right):
> 
>
https://codereview.chromium.org/1934453003/diff/1/src/base/platform/platform....
> src/base/platform/platform.h:244: : library_path(library_path), start(start),
> end(end), slide(slide) {}
> On 2016/04/30 10:37:10, noordhuis wrote:
> > I think this should use intptr_t for the slide because it can be negative;
> text
> > sections can be mapped before their default load addresses.  Because of
> > signed-to-unsigned conversion, logging such slides and adding them to
function
> > addresses in tickprocessor.js, produces bogus results.
> > 
> > intptr_t is what _dyld_get_image_vmaddr_slide() returns.  platform-macos.cc
> > currently gets this wrong, FWIW.
> 
> Acknowledged.

lgtm.

[Yang, 2016-05-02 06:41:01]

https://codereview.chromium.org/1934453003/diff/20001/src/base/platform/platf...
File src/base/platform/platform.h (right):

https://codereview.chromium.org/1934453003/diff/20001/src/base/platform/platf...
src/base/platform/platform.h:240: : library_path(library_path), start(start),
end(end), slide(0) {}
Can we call this aslr_slide across this whole CL? It makes that a bit easier to
understand for someone unfamiliar with this.

[fedor.indutny, 2016-05-02 07:33:21]

Thank you, Yang!

https://codereview.chromium.org/1934453003/diff/20001/src/base/platform/platf...
File src/base/platform/platform.h (right):

https://codereview.chromium.org/1934453003/diff/20001/src/base/platform/platf...
src/base/platform/platform.h:240: : library_path(library_path), start(start),
end(end), slide(0) {}
On 2016/05/02 06:41:01, Yang wrote:
> Can we call this aslr_slide across this whole CL? It makes that a bit easier
to
> understand for someone unfamiliar with this.

Acknowledged.

[fedor.indutny, 2016-05-02 07:33:29]

The CQ bit was checked by fedor@indutny.com

[fedor.indutny, 2016-05-02 07:33:29]

The patchset sent to the CQ was uploaded after l-g-t-m from yangguo@chromium.org
Link to the patchset: https://codereview.chromium.org/1934453003/#ps40001
(title: "rename")

[commit-bot: I haz the power, 2016-05-02 07:33:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1934453003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1934453003/40001

[commit-bot: I haz the power, 2016-05-02 08:00:58]

Description was changed from

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=
==========

to

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=
==========

[commit-bot: I haz the power, 2016-05-02 08:00:58]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-02 08:03:12]

Description was changed from

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=
==========

to

==========
[prof] export slide offset in profile log

When exporting `shared-library` in profile log, additionally export a
slide offset. This is required to parse profile logs generated on
systems with ASLR (OS X), otherwise it is impossible to assign C++
symbol names to their addresses in the log.

See: https://github.com/nodejs/node/issues/6466

BUG=

Committed: https://crrev.com/aee17a63b3b83753b271b01409459e538fa1822f
Cr-Commit-Position: refs/heads/master@{#35921}
==========

[commit-bot: I haz the power, 2016-05-02 08:03:12]

Patchset 3 (id:??) landed as
https://crrev.com/aee17a63b3b83753b271b01409459e538fa1822f
Cr-Commit-Position: refs/heads/master@{#35921}