VM: Share some stub code between isolates.

VM: Share some stub code between isolates.

This CL also lifts the restriction that the object pool can't be used
in VM isolate code on x64 and arm64.

Stubs that perform allocation can't be shared yet, because the inline allocation
code is not yet isolate-independent. This will be added in a separate CL.


BUG=
R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/81deeaeedcbffc89d8725be02446c6020f0e3e62

[Florian Schneider, 2015-07-10 12:50:01]

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

[rmacnak, 2015-07-10 20:34:21]

LGTM

[rmacnak, 2015-07-10 20:37:39]

https://chromiumcodereview.appspot.com/1229283002/diff/20001/runtime/vm/stub_...
File runtime/vm/stub_code_ia32.cc (right):

https://chromiumcodereview.appspot.com/1229283002/diff/20001/runtime/vm/stub_...
runtime/vm/stub_code_ia32.cc:1349: __ testl(EAX, EAX);
why not 

    __ LoadIsolate(EAX);
    __ cmpb(Address(EAX, Isolate::single_step_offset()), Immediate(0));

like x64?

[Florian Schneider, 2015-07-13 07:53:41]

https://chromiumcodereview.appspot.com/1229283002/diff/20001/runtime/vm/stub_...
File runtime/vm/stub_code_ia32.cc (right):

https://chromiumcodereview.appspot.com/1229283002/diff/20001/runtime/vm/stub_...
runtime/vm/stub_code_ia32.cc:1349: __ testl(EAX, EAX);
On 2015/07/10 20:37:38, rmacnak wrote:
> why not 
> 
>     __ LoadIsolate(EAX);
>     __ cmpb(Address(EAX, Isolate::single_step_offset()), Immediate(0));
> 
> like x64?

done.

[Florian Schneider, 2015-07-13 08:00:56]

Committed patchset #3 (id:40001) manually as
81deeaeedcbffc89d8725be02446c6020f0e3e62 (presubmit successful).