Add a getter for the address and size of the code range to the pulic API

Add a getter for the address and size of the code range to the pulic API

Since the x64 backend currently doesn't emit ABI compliant code, it is
not possible to unwind the stack. During Win64 SEH this will cause the
exception handling to abort, and not even call the unhandled exception
handler. Embedders are advised to install a custom unwind callback using
RtlInstallFunctionTableCallback for the entire code range to catch
unwind attempts for exception handling.

BUG=v8:3598
R=svenpanne@chromium.org
LOG=y

Committed: https://code.google.com/p/v8/source/detail?r=24283

[Sven Panne, 2014-09-29 11:41:51]

LGTM with a nit.

https://codereview.chromium.org/612043002/diff/20001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/612043002/diff/20001/src/api.cc#newcode6818
src/api.cc:6818: if (isolate->code_range() && isolate->code_range()->valid()) {
I think the first part of the conjunction will always be true, now that we
always have initialized Isolates.

[jochen (gone - plz use gerrit), 2014-09-29 11:43:18]

https://codereview.chromium.org/612043002/diff/20001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/612043002/diff/20001/src/api.cc#newcode6818
src/api.cc:6818: if (isolate->code_range() && isolate->code_range()->valid()) {
On 2014/09/29 at 11:41:51, Sven Panne wrote:
> I think the first part of the conjunction will always be true, now that we
always have initialized Isolates.

no, we only create a code range on 64bit

[Sven Panne, 2014-09-29 11:48:25]

https://codereview.chromium.org/612043002/diff/20001/src/api.cc
File src/api.cc (right):

https://codereview.chromium.org/612043002/diff/20001/src/api.cc#newcode6818
src/api.cc:6818: if (isolate->code_range() && isolate->code_range()->valid()) {
On 2014/09/29 11:43:17, jochen wrote:
> On 2014/09/29 at 11:41:51, Sven Panne wrote:
> > I think the first part of the conjunction will always be true, now that we
> always have initialized Isolates.
> 
> no, we only create a code range on 64bit

I think we *always* create a CodeRange, but it's only valid() on x64. If that's
a good overall design is another question... :-)

[jochen (gone - plz use gerrit), 2014-09-29 12:17:41]

Committed patchset #2 (id:20001) manually as 24283 (presubmit successful).