VM: Use PC offset instead of absolute PC in exception handler info.

VM: Use PC offset instead of absolute PC in exception handler info.

Similar to the change I did for PC descriptors: We can save space by
using a uint32_t for the offset, instead of a uword for the absolute pc.

R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43138

[Florian Schneider, 2015-01-23 15:34:18]

fschneider@google.com changed reviewers:
+ srdjan@google.com

[srdjan, 2015-01-23 16:55:28]

lgtm

https://codereview.chromium.org/868103002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/868103002/diff/1/runtime/vm/object.cc#newcode...
runtime/vm/object.cc:10952: info->handler_pc_offset = handler_pc_offset;
Could you add an assert that on 64-bit handler_pc_offset content is not bigger
than uin32_t?

[Florian Schneider, 2015-01-26 15:28:53]

https://codereview.chromium.org/868103002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/868103002/diff/1/runtime/vm/object.cc#newcode...
runtime/vm/object.cc:10952: info->handler_pc_offset = handler_pc_offset;
On 2015/01/23 16:55:28, srdjan wrote:
> Could you add an assert that on 64-bit handler_pc_offset content is not bigger
> than uin32_t?

Done. I didn't use Utils::IsUint because it does not compile cross-platform for
unsigned types.

[Florian Schneider, 2015-01-26 15:40:24]

Committed patchset #2 (id:20001) manually as r43138 (presubmit successful).