Use special allocation functions for object creation while deserializing from a full snapshot in ...

Use special allocation functions for object creation while deserializing from a full snapshot in order to avoid the following:
- unnecessary initialization of objects with null
- avoid handle creation
Committed: https://code.google.com/p/dart/source/detail?r=3380

[Ivan Posva, 2012-01-16 19:30:33]

LGTM with comments.

-Ivan

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc
File vm/raw_object_snapshot.cc (right):

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:14: (kind == Snapshot::kFull) ? reader->New##type() :
type::New()
Parens around this expression to avoid being surprised when
NEW_OBJECT(Foo)->toBar()
does not what you want.

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1269: str_obj->SetHash(hash);
The hash should be calculated as the string is deserialized. Different change...

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1291: str_obj.SetHash(hash);
ditto for hash calculation: Recalculate during the read below?

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1292: for (intptr_t i = 0; i < len; i++) {
ASSERT(*str_obj.CharAddr(i) != NULL);
and avoid the handle operations for full snapshots.

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.cc
File vm/snapshot.cc (right):

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.cc#newcode66
vm/snapshot.cc:66: backward_references_((snapshot->kind() == Snapshot::kFull) ?
1024 : 4) {
1024 and 4 seem like magic numbers. What do we need for loading the core library
snapshot?

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.h
File vm/snapshot.h (right):

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.h#newcode343
vm/snapshot.h:343: void NewArray(Array* array, intptr_t len);
RawArray* NewArray(intptr_t len);

[siva, 2012-01-18 00:00:24]

Addressed comments.

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc
File vm/raw_object_snapshot.cc (right):

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:14: (kind == Snapshot::kFull) ? reader->New##type() :
type::New()
On 2012/01/16 19:30:33, Ivan Posva wrote:
> Parens around this expression to avoid being surprised when
> NEW_OBJECT(Foo)->toBar()
> does not what you want.

Done.

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1269: str_obj->SetHash(hash);
In this case I will set the hash value to 0 so that it will
get computed when needed.

On 2012/01/16 19:30:33, Ivan Posva wrote:
> The hash should be calculated as the string is deserialized. Different
change...

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1291: str_obj.SetHash(hash);
In the full snapshot case I added an ASSERT to
ensure that the hash value read is equal to the computed
value. That way it does not have to be computed while reading.

On 2012/01/16 19:30:33, Ivan Posva wrote:
> ditto for hash calculation: Recalculate during the read below?

http://codereview.chromium.org/9139067/diff/15002/vm/raw_object_snapshot.cc#n...
vm/raw_object_snapshot.cc:1292: for (intptr_t i = 0; i < len; i++) {
On 2012/01/16 19:30:33, Ivan Posva wrote:
> ASSERT(*str_obj.CharAddr(i) != NULL);
> and avoid the handle operations for full snapshots.

Done.

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.cc
File vm/snapshot.cc (right):

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.cc#newcode66
vm/snapshot.cc:66: backward_references_((snapshot->kind() == Snapshot::kFull) ?
1024 : 4) {
Added two constants one for the full snapshot case and one for all other
snapshots.

On 2012/01/16 19:30:33, Ivan Posva wrote:
> 1024 and 4 seem like magic numbers. What do we need for loading the core
library
> snapshot?

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.h
File vm/snapshot.h (right):

http://codereview.chromium.org/9139067/diff/15002/vm/snapshot.h#newcode343
vm/snapshot.h:343: void NewArray(Array* array, intptr_t len);
On 2012/01/16 19:30:33, Ivan Posva wrote:
> RawArray* NewArray(intptr_t len);

Done.