Tweaks to perf jitdump support

Tweaks to perf jitdump support

BUG=
R=asiva@google.com, vegorov@google.com

Committed: https://code.google.com/p/dart/source/detail?r=39427

[Cutch, 2014-08-20 19:23:07]

Siva,

Please verify the change in method names we report in object.cc is okay.

[Cutch, 2014-08-20 19:43:39]

On 2014/08/20 19:23:07, Cutch wrote:
> Siva,
> 
> Please verify the change in method names we report in object.cc is okay.

Slava- using the shorter name could lead to conflicts. e.g. two libraries have
Montgomery_reduce and you wouldn't be able to tell which is which. Do you have
any guidance on what kind of short name you're after?

Thanks,
John

[Vyacheslav Egorov (Google), 2014-08-20 20:14:40]

I will be fine with 

library_name.class_name.method_name

this should be pretty unique overall

https://codereview.chromium.org/489923002/diff/20001/runtime/vm/os_linux.cc
File runtime/vm/os_linux.cc (right):

https://codereview.chromium.org/489923002/diff/20001/runtime/vm/os_linux.cc#n...
runtime/vm/os_linux.cc:159: const char* format = "perf-%" Pd ".jitdump";
perf is writing output into perf.data so I think we should just remove the PID
mangling altogether here.

[Cutch, 2014-08-20 20:31:35]

PTAL

[Vyacheslav Egorov (Google), 2014-08-20 20:37:01]

LGTM

[siva, 2014-08-20 20:40:09]

lgtm

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc#new...
runtime/vm/object.cc:5827: QualifiedFunctionLibKind lib_kind =
kQualifiedFunctionLibKindLibUrl) {
instead of a default value for the param why not just pass this in.
There are only two call points for this function.

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc#new...
runtime/vm/object.cc:5851: UNIMPLEMENTED();
UNREACHABLE() instead of unimplemented?

[Cutch, 2014-08-20 20:43:41]

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc#new...
runtime/vm/object.cc:5827: QualifiedFunctionLibKind lib_kind =
kQualifiedFunctionLibKindLibUrl) {
On 2014/08/20 20:40:09, siva wrote:
> instead of a default value for the param why not just pass this in.
> There are only two call points for this function.

Done.

https://codereview.chromium.org/489923002/diff/60001/runtime/vm/object.cc#new...
runtime/vm/object.cc:5851: UNIMPLEMENTED();
On 2014/08/20 20:40:09, siva wrote:
> UNREACHABLE() instead of unimplemented?

Done.

[Cutch, 2014-08-20 20:43:59]

Committed patchset #5 manually as 39427 (presubmit successful).