Fix bug in receiver-phi computation.

Fix bug in receiver-phi computation.

This fixes a bug in my previous CL (https://codereview.chromium.org/1841073003/)

Computes the is-receiver property on demand, but for all phis at once using a worklist-approach.

BUG=
R=vegorov@google.com

Committed: https://github.com/dart-lang/sdk/commit/4b5d05e12fdefdb9a3379b6e57cf1d9e64d11851

[Florian Schneider, 2016-03-31 21:19:22]

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

[Florian Schneider, 2016-03-31 21:19:22]

Ptal. So far I could only make a regression test that required reversing the
order in which phi-inputs are processed in the old code.

[Vyacheslav Egorov (Google), 2016-04-01 11:07:59]

https://codereview.chromium.org/1851653002/diff/1/runtime/vm/flow_graph.cc
File runtime/vm/flow_graph.cc (right):

https://codereview.chromium.org/1851653002/diff/1/runtime/vm/flow_graph.cc#ne...
runtime/vm/flow_graph.cc:429: ComputeIsReceiver();
I still think it is much better to just fix the existing algorithm instead of
revisiting the whole graph:

void FlowGraph::ComputeIsReceiverRecursive(PhiInstr* phi,
                                           GrowableArray<PhiInstr*>* unmark)
const {
  if (phi->is_receiver() != PhiInstr::kUnknownReceiver) return;
  phi->set_is_receiver(PhiInstr::kReceiver);
  for (intptr_t i = 0; i < phi->InputCount(); ++i) {
    Definition* def = phi->InputAt(i)->definition();
    if (def->IsParameter() && (def->AsParameter()->index() == 0)) continue;
    if (!def->IsPhi()) {
      phi->set_is_receiver(PhiInstr::kNotReceiver);
      break;
    }
    ComputeIsReceiverRecursive(def->AsPhi(), unmark);
    if (def->AsPhi()->is_receiver() == PhiInstr::kNotReceiver) {
      phi->set_is_receiver(PhiInstr::kNotReceiver);
      break;
    }
  }

  if (phi->is_receiver() == PhiInstr::kNotReceiver) {
    unmark->Add(phi);
  }
}

void FlowGraph::ComputeIsReceiver(PhiInstr* phi) const {
  GrowableArray<PhiInstr*> unmark;
  ComputeIsReceiverRecursive(phi, &unmark);

  // Now drain unmark.
  while (!unmark.is_empty()) {
    PhiInstr* phi = unmark.RemoveLast();
    for (Value::Iterator it(phi->input_use_list());
         !it.Done();
         it.Advance()) {
      PhiInstr* use = it.Current()->instruction()->AsPhi();
      if ((use != NULL) && (use->is_receiver() == kReceiver)) {
        use->set_is_receiver(PhiInstr::kNotReceiver);
        unmark.Add(use);
      }
    }
  } 
}

[Florian Schneider, 2016-04-01 18:20:40]

Ptal

[Vyacheslav Egorov (Google), 2016-04-02 06:21:23]

lgtm

[Florian Schneider, 2016-04-02 20:51:07]

Description was changed from

==========
Fix bug in receiver-phi computation.

This fixes a bug in my previous CL (https://codereview.chromium.org/1841073003/)

Computes the is-receiver property on demand, but for all phis at once using a
worklist-approach.

BUG=
==========

to

==========
Fix bug in receiver-phi computation.

This fixes a bug in my previous CL (https://codereview.chromium.org/1841073003/)

Computes the is-receiver property on demand, but for all phis at once using a
worklist-approach.

BUG=
R=vegorov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/4b5d05e12fdefdb9a3379b6e57cf1d9e64d11851
==========

[Florian Schneider, 2016-04-02 20:51:08]

Committed patchset #2 (id:20001) manually as
4b5d05e12fdefdb9a3379b6e57cf1d9e64d11851 (presubmit successful).