Script for parsing of verbose linker output

Script for parsing of verbose linker output

When trying to understand why particular symbols are pulled in to a
binary it can be helpful to examine the verbose linker output.
However it quickly becomes unwieldy. This parses it and allows
querying of it to explain why a particular object file is pulled
in. This was used in the investigation of the linked bug, and others.

BUG=630755
Committed: https://crrev.com/de77b2055e40cab9321479335ffd3b8416c3e34c
Cr-Commit-Position: refs/heads/master@{#437730}

[brucedawson, 2016-12-09 01:22:40]

brucedawson@chromium.org changed reviewers:
+ stanisc@chromium.org

[brucedawson, 2016-12-09 01:22:41]

PTAL - this is the first of three related scripts to aid in linker
investigations.

[stanisc, 2016-12-10 00:13:11]

LGTM (although my Python knowledge if fairly limited).

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
File tools/win/linker_verbose_tracking.py (right):

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:55: obj_match =
re.compile('.*\((.*)\.obj\)')
It would help to see a comment with an example of matching string (just because
my regular expression skills are a bit rusty and all the escaping makes it
harder to read the pattern). I guess it is any sequence of characters followed
by an obj file name in parenthesis.

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:117: symbol = cross_refed_symbols[target]
Does this need to be inside the inner for loop?

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:131: print r'Sample: %s
chrome_dll_verbose.txt SkTLS'
It looks like this also needs % sys.argv[0] argument

[brucedawson, 2016-12-10 00:59:57]

Good review. You found a bug and a design flaw. Both are fixed now.

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
File tools/win/linker_verbose_tracking.py (right):

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:55: obj_match =
re.compile('.*\((.*)\.obj\)')
On 2016/12/10 00:13:11, stanisc wrote:
> It would help to see a comment with an example of matching string (just
because
> my regular expression skills are a bit rusty and all the escaping makes it
> harder to read the pattern). I guess it is any sequence of characters followed
> by an obj file name in parenthesis.

Done.

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:117: symbol = cross_refed_symbols[target]
On 2016/12/10 00:13:11, stanisc wrote:
> Does this need to be inside the inner for loop?

Good point. And since it is invariant for the target it should actually only be
printed once, so I've changed the output format slightly.

https://codereview.chromium.org/2564543003/diff/20001/tools/win/linker_verbos...
tools/win/linker_verbose_tracking.py:131: print r'Sample: %s
chrome_dll_verbose.txt SkTLS'
On 2016/12/10 00:13:11, stanisc wrote:
> It looks like this also needs % sys.argv[0] argument

Good catch. Done.

[brucedawson, 2016-12-10 01:22:19]

The CQ bit was checked by brucedawson@chromium.org

[brucedawson, 2016-12-10 01:22:20]

The patchset sent to the CQ was uploaded after l-g-t-m from stanisc@chromium.org
Link to the patchset: https://codereview.chromium.org/2564543003/#ps40001
(title: "Code review tweaks and improvements")

[commit-bot: I haz the power, 2016-12-10 01:23:12]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-12-10 02:36:17]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1481332939721470,
"parent_rev": "3059ffe1e627250c991ba0938352bec89d6f4211", "commit_rev":
"b042e1a9e7bdf0e04b1ab30c8392a1e0bd05ac11"}

[commit-bot: I haz the power, 2016-12-10 02:36:56]

Description was changed from

==========
Script for parsing of verbose linker output

When trying to understand why particular symbols are pulled in to a
binary it can be helpful to examine the verbose linker output.
However it quickly becomes unwieldy. This parses it and allows
querying of it to explain why a particular object file is pulled
in. This was used in the investigation of the linked bug, and others.

BUG=630755
==========

to

==========
Script for parsing of verbose linker output

When trying to understand why particular symbols are pulled in to a
binary it can be helpful to examine the verbose linker output.
However it quickly becomes unwieldy. This parses it and allows
querying of it to explain why a particular object file is pulled
in. This was used in the investigation of the linked bug, and others.

BUG=630755

Review-Url: https://codereview.chromium.org/2564543003
==========

[commit-bot: I haz the power, 2016-12-10 02:36:57]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-12-12 15:05:38]

Description was changed from

==========
Script for parsing of verbose linker output

When trying to understand why particular symbols are pulled in to a
binary it can be helpful to examine the verbose linker output.
However it quickly becomes unwieldy. This parses it and allows
querying of it to explain why a particular object file is pulled
in. This was used in the investigation of the linked bug, and others.

BUG=630755

Review-Url: https://codereview.chromium.org/2564543003
==========

to

==========
Script for parsing of verbose linker output

When trying to understand why particular symbols are pulled in to a
binary it can be helpful to examine the verbose linker output.
However it quickly becomes unwieldy. This parses it and allows
querying of it to explain why a particular object file is pulled
in. This was used in the investigation of the linked bug, and others.

BUG=630755

Committed: https://crrev.com/de77b2055e40cab9321479335ffd3b8416c3e34c
Cr-Commit-Position: refs/heads/master@{#437730}
==========

[commit-bot: I haz the power, 2016-12-12 15:05:38]

Patchset 3 (id:??) landed as
https://crrev.com/de77b2055e40cab9321479335ffd3b8416c3e34c
Cr-Commit-Position: refs/heads/master@{#437730}