Add a script cache to the debugger...

Add a script cache to the debugger

When loaded scripts are requested this cache is filled with all the script objects in the heap. Hereafter its content is kept in sync with the active scripts in the heap through the notifications of new scripts compiled and by using weak handles to get notified when a script is collected.

Through the tracking of collected scripts the debugger event OnScriptCollected have been added to notify a debugger that a script previously returned through the scripts command is no longer in use.

Make the ComputeIntegerHash globally available.

Moved clearing of the mirror cache to when debugger is really left. Previously recursive invocations of the debugger cause the mirror cache to be cleared causing handles to become either stale or reference other objects.

Committed: http://code.google.com/p/v8/source/detail?r=1988

[Søren Thygesen Gjesse, 2009-05-18 12:21:39]

The main reason to postpone initialization the debugger script cache until
loaded scripts are actually requested is that in Chrome the v8::Debug::Call is
used for providing source location information for unhanded exceptions.
Initializing the debugger script cache for this use might cause performance
regressions when running Chrome without really using the debugger.

[Mads Ager (chromium), 2009-05-18 12:57:00]

LGTM

http://codereview.chromium.org/115462/diff/1005/1015
File src/debug.cc (right):

http://codereview.chromium.org/115462/diff/1005/1015#newcode553
Line 553: HandleScope scope;
Why do you need to create this handle to the script?

http://codereview.chromium.org/115462/diff/1005/1015#newcode1570
Line 1570: // Perform GC to get unreferenced scripts evicted from the cache
before before
before before -> before

http://codereview.chromium.org/115462/diff/1005/1010
File src/debug.h (right):

http://codereview.chromium.org/115462/diff/1005/1010#newcode151
Line 151: // the hash map holding the cache is the script id.
I would just write "The key used in the cache is the script id."

[Søren Thygesen Gjesse, 2009-05-18 13:13:17]

http://codereview.chromium.org/115462/diff/1005/1015
File src/debug.cc (right):

http://codereview.chromium.org/115462/diff/1005/1015#newcode553
Line 553: HandleScope scope;
On 2009/05/18 12:57:00, Mads Ager wrote:
> Why do you need to create this handle to the script?

I don't - unused code.

http://codereview.chromium.org/115462/diff/1005/1015#newcode1570
Line 1570: // Perform GC to get unreferenced scripts evicted from the cache
before before
On 2009/05/18 12:57:00, Mads Ager wrote:
> before before -> before

Done.

http://codereview.chromium.org/115462/diff/1005/1010
File src/debug.h (right):

http://codereview.chromium.org/115462/diff/1005/1010#newcode151
Line 151: // the hash map holding the cache is the script id.
On 2009/05/18 12:57:00, Mads Ager wrote:
> I would just write "The key used in the cache is the script id."

Done.