Getting value of local variables on stack trace

Getting value of local variables on stack trace

Introduce concept of scope in local variable info, according
to mirror proposal.
Committed: https://code.google.com/p/dart/source/detail?r=3017

[siva, 2012-01-05 02:01:45]

LGTM with comment regarding scope_id

http://codereview.chromium.org/8983034/diff/1/runtime/vm/scopes.cc
File runtime/vm/scopes.cc (right):

http://codereview.chromium.org/8983034/diff/1/runtime/vm/scopes.cc#newcode188
runtime/vm/scopes.cc:188: }
This seems kind of fragile as it assumes that all the variables in a scope will
be consecutive in 'vars'.
Why not add a scope_id field to LocalScope and assign a scope_id value when a
new LocalScope is created.

[hausner, 2012-01-05 22:33:21]

Thank you for the review.

http://codereview.chromium.org/8983034/diff/1/runtime/vm/scopes.cc
File runtime/vm/scopes.cc (right):

http://codereview.chromium.org/8983034/diff/1/runtime/vm/scopes.cc#newcode188
runtime/vm/scopes.cc:188: }
On 2012/01/05 02:01:45, asiva wrote:
> This seems kind of fragile as it assumes that all the variables in a scope
will
> be consecutive in 'vars'.
> Why not add a scope_id field to LocalScope and assign a scope_id value when a
> new LocalScope is created. 

True. CollectLocalVariables() function below makes sure that all variables of a
scope are consecutive in the vars array. Added a comment to describe this.

The nice thing about this solution (rather than generating scope ids globally)
is that the parameters are always in scope 0. Also, we don't have to maintain a
global id counter (or add one to the isolate).