Decompiler improvements.

Decompiler improvements.

The main motivation is simplifying profiling activities:

1) Use hex instead of decimal for offsets, just like perf does. This
affects --print-opt-code

2) When printing block information, indicate loop information: if
block is header, where the end is; if block is in a loop, where the
loop starts. This affects --code-comments.

Using --print-opt-code --code-comments, and cross-referencing with data
obtained from perf, one may now find the block a hotspot belongs to
without needing to do hex2dec/dec2hex conversions. Once found, loop info
is available locally, on the block.

BUG=

Committed: https://crrev.com/32f4bd659d38eb5485eedb1d0dd236ff1bdc01d5
Cr-Commit-Position: refs/heads/master@{#28964}

[Mircea Trofin, 2015-06-11 03:28:04]

mtrofin@chromium.org changed reviewers:
+ jarin@chromium.org, jvoung@chromium.org, stichnot@chromium.org

[Mircea Trofin, 2015-06-11 03:29:38]

Pretty printing improvements pulled out from the register allocation work. 

I believe this also updates all offset printouts to hex, consistently. I have
chosen not to offer a flag for "decimal vs hex" for offsets - happy to add one,
if we feel we need it.

[Jarin, 2015-06-11 04:22:29]

lgtm with a nit.

https://codereview.chromium.org/1177123002/diff/1/src/compiler/code-generator.cc
File src/compiler/code-generator.cc (right):

https://codereview.chromium.org/1177123002/diff/1/src/compiler/code-generator...
src/compiler/code-generator.cc:101: auto buffer_start = buffer.start();
auto -> char*

[Mircea Trofin, 2015-06-11 19:00:28]

The CQ bit was checked by mtrofin@chromium.org

[Mircea Trofin, 2015-06-11 19:00:28]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1177123002/#ps20001
(title: " ")

[commit-bot: I haz the power, 2015-06-11 19:00:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1177123002/20001

[Mircea Trofin, 2015-06-11 19:00:56]

FYI - incorporated feedback, waiting for CQ.

https://codereview.chromium.org/1177123002/diff/1/src/compiler/code-generator.cc
File src/compiler/code-generator.cc (right):

https://codereview.chromium.org/1177123002/diff/1/src/compiler/code-generator...
src/compiler/code-generator.cc:101: auto buffer_start = buffer.start();
On 2015/06/11 04:22:29, jarin wrote:
> auto -> char*

Done.

[commit-bot: I haz the power, 2015-06-11 20:10:30]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-11 20:10:50]

Patchset 2 (id:??) landed as
https://crrev.com/32f4bd659d38eb5485eedb1d0dd236ff1bdc01d5
Cr-Commit-Position: refs/heads/master@{#28964}

[Michael Starzinger, 2015-06-16 10:36:42]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1188093002/ by mstarzinger@chromium.org.

The reason for reverting is: Code printout has become unreadable. Offsets are
printed in decimal numbers everywhere else. This is inconsistent with the rest
of the code-base. Some examples are tables for deoptimization data, safepoints
and exception handlers. I would be fine with this change if _all_ tracing would
be adapted. But there are _many_ places to touch..

[Mircea Trofin, 2015-06-17 00:06:32]

Patchset #3 (id:40001) has been deleted