Changes to prepare for allowing script snapshots to be taken after running the main application

Changes to prepare for allowing script snapshots to be taken after running the main application
- Update usage counter to optimization threshold or 0 depending on whether optimized code exists for the Function
- Do not serialize the resolved names cache and loaded scripts cache when doing script snapshots

BUG=
R=srdjan@google.com

Committed: https://github.com/dart-lang/sdk/commit/52c2319d481427c20f225ddf7d6bbd54b1baf851

[siva, 2015-08-31 22:13:22]

asiva@google.com changed reviewers:
+ hausner@google.com, srdjan@google.com

[srdjan, 2015-08-31 22:17:19]

lgtm

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:733: if
(Code::IsOptimized(ptr()->instructions_->ptr()->code_)) {
Why are you not doing:

ptr()->instructions_->ptr()->code_->is_optimized() 

Readability?

[hausner, 2015-08-31 22:36:48]

DBC

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:734:
writer->Write<int32_t>(FLAG_optimization_counter_threshold);
Can the snapshot be written in a VM instance where the optimization threshold is
100, and then read and used in a VM where the threshold is 1000? Would that be a
problem?

[siva, 2015-08-31 23:00:19]

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:733: if
(Code::IsOptimized(ptr()->instructions_->ptr()->code_)) {
On 2015/08/31 22:17:18, srdjan wrote:
> Why are you not doing:
> 
> ptr()->instructions_->ptr()->code_->is_optimized() 
> 
> Readability?

This is better, I changed the code.

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:734:
writer->Write<int32_t>(FLAG_optimization_counter_threshold);
On 2015/08/31 22:36:48, hausner wrote:
> Can the snapshot be written in a VM instance where the optimization threshold
is
> 100, and then read and used in a VM where the threshold is 1000? Would that be
a
> problem?

Discussed offline with Srdjan, there should not be a problem, if the threshold
is lowered there would be no effect, functions will get optimized right away, if
the threshold is increased functions would take longer but the snapshot version
itself would be incompatible.

[siva, 2015-08-31 23:14:27]

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
File runtime/vm/raw_object_snapshot.cc (right):

https://codereview.chromium.org/1329503002/diff/20001/runtime/vm/raw_object_s...
runtime/vm/raw_object_snapshot.cc:733: if
(Code::IsOptimized(ptr()->instructions_->ptr()->code_)) {
On 2015/08/31 23:00:19, siva wrote:
> On 2015/08/31 22:17:18, srdjan wrote:
> > Why are you not doing:
> > 
> > ptr()->instructions_->ptr()->code_->is_optimized() 
> > 
> > Readability?
> 
> This is better, I changed the code.

Actually I take that back, the reason I did that was because is_optimized() only
works if there is a handle for the code object. We are dealing with a raw
pointer here.

[siva, 2015-08-31 23:36:28]

Committed patchset #4 (id:60001) manually as
52c2319d481427c20f225ddf7d6bbd54b1baf851 (presubmit successful).