Implement AggregatableHistogramTimer and use it to measure how much time

Implement AggregatableHistogramTimer and use it to measure how much time
of running a script is really spent in compilation. That is, sum up the
total time spent compiling (parsing + compile proper) within a run call
as seen through the API.

@jochen: So many questions:
- Is it ok to re-use V8.CompileLazy?
  This measures something a little different.
- clang-format does funny things to the huge macro definitions.
  I accepted clang-format changes for all code, but reverted for
  the #define orgies in counters.h. ok?
- Am I measuring the right thing. That is, are Aggregat[ing|ed]TimerScope
  in the right place?

I'll fiddle a bit more with this to see if it does the right thing. Would
be happy if you could still review now-ish.

BUG=

Committed: https://crrev.com/6f9d60cc6f78467ebc44300213c07dc21832d10b
Cr-Commit-Position: refs/heads/master@{#26226}

[vogelheim, 2015-01-21 14:32:59]

vogelheim@chromium.org changed reviewers:
+ jochen@chromium.org

[Yang, 2015-01-21 14:40:39]

yangguo@chromium.org changed reviewers:
+ yangguo@chromium.org

[Yang, 2015-01-21 14:40:40]

https://codereview.chromium.org/790413004/diff/1/src/compiler.cc
File src/compiler.cc (right):

https://codereview.chromium.org/790413004/diff/1/src/compiler.cc#newcode943
src/compiler.cc:943: AggregatedHistogramTimerScope
timer(isolate->counters()->compile_lazy());
This may be re-entrant. When we compile and encounter a late syntax error, that
error is reported. The error reporting is partly written in JS, which also needs
to be compiled lazily.

See implementation for HistogramTimerScope.

[vogelheim, 2015-01-21 14:59:55]

On 2015/01/21 14:40:40, Yang wrote:
> https://codereview.chromium.org/790413004/diff/1/src/compiler.cc
> File src/compiler.cc (right):
> 
> https://codereview.chromium.org/790413004/diff/1/src/compiler.cc#newcode943
> src/compiler.cc:943: AggregatedHistogramTimerScope
> timer(isolate->counters()->compile_lazy());
> This may be re-entrant. When we compile and encounter a late syntax error,
that
> error is reported. The error reporting is partly written in JS, which also
needs
> to be compiled lazily.
> 
> See implementation for HistogramTimerScope.

Thanks.

I saw that. My thinking was:

- For HistogramTimerScope, the base::ElapsedTimer - which appears to be the
problem - is in the timer, not in the scope. So when that function is called
recursively, two scopes will try to modify the same base::ElapsedTimer instance
=> problem.
- For my aggregating timer thingy, the ElapsedTimer is in the scopes. These are
on the stack and not shared in any fashion, so the problem that two entities try
to control the same base::ElapsedTimer shouldn't occur.

Not sure if I was overthinking or underthinking this... wdyt?

[Yang, 2015-01-21 15:17:32]

On 2015/01/21 14:59:55, vogelheim wrote:
> On 2015/01/21 14:40:40, Yang wrote:
> > https://codereview.chromium.org/790413004/diff/1/src/compiler.cc
> > File src/compiler.cc (right):
> > 
> > https://codereview.chromium.org/790413004/diff/1/src/compiler.cc#newcode943
> > src/compiler.cc:943: AggregatedHistogramTimerScope
> > timer(isolate->counters()->compile_lazy());
> > This may be re-entrant. When we compile and encounter a late syntax error,
> that
> > error is reported. The error reporting is partly written in JS, which also
> needs
> > to be compiled lazily.
> > 
> > See implementation for HistogramTimerScope.
> 
> Thanks.
> 
> I saw that. My thinking was:
> 
> - For HistogramTimerScope, the base::ElapsedTimer - which appears to be the
> problem - is in the timer, not in the scope. So when that function is called
> recursively, two scopes will try to modify the same base::ElapsedTimer
instance
> => problem.
> - For my aggregating timer thingy, the ElapsedTimer is in the scopes. These
are
> on the stack and not shared in any fashion, so the problem that two entities
try
> to control the same base::ElapsedTimer shouldn't occur.
> 
> Not sure if I was overthinking or underthinking this... wdyt?

I see. Seems alright then.

[jochen (gone - plz use gerrit), 2015-01-22 16:15:03]

lgtm

any more comments from you, Yang?

[Yang, 2015-01-22 16:17:48]

On 2015/01/22 16:15:03, jochen (slow) wrote:
> lgtm
> 
> any more comments from you, Yang?

Nope. Lgtm.

[vogelheim, 2015-01-22 17:36:36]

The CQ bit was checked by vogelheim@chromium.org

[commit-bot: I haz the power, 2015-01-22 17:37:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/790413004/40001

[commit-bot: I haz the power, 2015-01-22 18:38:28]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-01-22 18:38:46]

Patchset 3 (id:??) landed as
https://crrev.com/6f9d60cc6f78467ebc44300213c07dc21832d10b
Cr-Commit-Position: refs/heads/master@{#26226}