VM: Improve specialization of calls on receiver in AOT mode.

VM: Improve specialization of calls on receiver in AOT mode.

When encountering call this.m(...) we can check if m resolves to the same
method in all concrete subclasses of the receiver class. If it does then
we don't need any checks and can just use a StaticCall instead of InstanceCall.

This is allows us to improve code quality for cases like:

    class Base {
      var _field;

      foo() { _field = true; }
    }

    class A01 extends Base { }
    ...
    class A16 extends Base { }

Previously AOT would generate InstanceCall(get:_field) in the method foo.

However with this change we generate StaticCall(...) which subsequently gets
handled by the inliner.

R=fschneider@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/ec9b1c385a4e7824cf133cffb834bb38d65fe1fc

[Florian Schneider, 2016-06-10 15:30:18]

Lgtm.

https://codereview.chromium.org/2055263002/diff/1/runtime/vm/aot_optimizer.cc
File runtime/vm/aot_optimizer.cc (right):

https://codereview.chromium.org/2055263002/diff/1/runtime/vm/aot_optimizer.cc...
runtime/vm/aot_optimizer.cc:2545: StaticCallInstr* call = new (Z)
StaticCallInstr(
Alternatively, maybe you can combine this with the polymorphic case below: make
a PolymorphicInstanceCall with with_checks = false, complete = true for this
case, which will be like a StaticCall.

[Vyacheslav Egorov (Google), 2016-06-10 16:05:06]

https://codereview.chromium.org/2055263002/diff/1/runtime/vm/aot_optimizer.cc
File runtime/vm/aot_optimizer.cc (right):

https://codereview.chromium.org/2055263002/diff/1/runtime/vm/aot_optimizer.cc...
runtime/vm/aot_optimizer.cc:2545: StaticCallInstr* call = new (Z)
StaticCallInstr(
On 2016/06/10 15:30:18, Florian Schneider wrote:
> Alternatively, maybe you can combine this with the polymorphic case below:
make
> a PolymorphicInstanceCall with with_checks = false, complete = true for this
> case, which will be like a StaticCall.

I considered combining it - but then I need to create an ICData - which I think
is useless to do.

[Vyacheslav Egorov (Google), 2016-06-10 16:12:51]

Description was changed from

==========
VM: Improve specialization of calls on receiver in AOT mode.

When encountering call this.m(...) we can check if m resolves to the same
method in all concrete subclasses of the receiver class. If it does then
we don't need any checks and can just use a StaticCall instead of InstanceCall.

This is allows us to improve code quality for cases like:

    class Base {
      var _field;

      foo() { _field = true; }
    }

    class A01 extends Base { }
    ...
    class A16 extends Base { }

Previously AOT would generate InstanceCall(get:_field) in the method foo.

However with this change we generate StaticCall(...) which subsequently gets
handled by the inliner.

R=fschneider@google.com
BUG=
==========

to

==========
VM: Improve specialization of calls on receiver in AOT mode.

When encountering call this.m(...) we can check if m resolves to the same
method in all concrete subclasses of the receiver class. If it does then
we don't need any checks and can just use a StaticCall instead of InstanceCall.

This is allows us to improve code quality for cases like:

    class Base {
      var _field;

      foo() { _field = true; }
    }

    class A01 extends Base { }
    ...
    class A16 extends Base { }

Previously AOT would generate InstanceCall(get:_field) in the method foo.

However with this change we generate StaticCall(...) which subsequently gets
handled by the inliner.

R=fschneider@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/ec9b1c385a4e7824cf133cffb834bb38d65fe1fc
==========

[Vyacheslav Egorov (Google), 2016-06-10 16:12:52]

Committed patchset #1 (id:1) manually as
ec9b1c385a4e7824cf133cffb834bb38d65fe1fc (presubmit successful).