Shuffle around deopt id allocation to give the flow graph builder a chance to record other data as …

runtime/vm/branch_optimizer.cc

Index: runtime/vm/branch_optimizer.cc
diff --git a/runtime/vm/branch_optimizer.cc b/runtime/vm/branch_optimizer.cc
index f68bbcaef3379903f93cec3ce13d18b07e604846..00ef0c87ff27ed8b0bdc764f2c29929dc6ce7020 100644
--- a/runtime/vm/branch_optimizer.cc
+++ b/runtime/vm/branch_optimizer.cc
@@ -66,7 +66,8 @@ JoinEntryInstr* BranchSimplifier::ToJoinEntry(Zone* zone,
   // so the former true and false targets become joins of the control flows
   // from all the duplicated branches.
   JoinEntryInstr* join =
-      new (zone) JoinEntryInstr(target->block_id(), target->try_index());
+      new (zone) JoinEntryInstr(target->block_id(), target->try_index(),
+                                Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:00]

This can be Thread::kNoDeoptId because we copy the correct deopt id down below
in the InheritDeoptTarget.

   join->InheritDeoptTarget(zone, target);
   join->LinkTo(target->next());
   join->set_last_instruction(target->last_instruction());
@@ -82,7 +83,8 @@ BranchInstr* BranchSimplifier::CloneBranch(Zone* zone,
   ComparisonInstr* comparison = branch->comparison();
   ComparisonInstr* new_comparison =
       comparison->CopyWithNewOperands(new_left, new_right);
-  BranchInstr* new_branch = new (zone) BranchInstr(new_comparison);
+  BranchInstr* new_branch = new (zone)
+      BranchInstr(new_comparison, Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:00]

This should probably be Thread::kNoDeoptId

(e.g. it does not make much sense to assign new deoptimization ids to anything
created during optimizations - because they don't "lead" anywhere)

   return new_branch;
 }
 
@@ -183,20 +185,24 @@ void BranchSimplifier::Simplify(FlowGraph* flow_graph) {
 
         // Connect the branch to the true and false joins, via empty target
         // blocks.
-        TargetEntryInstr* true_target = new (zone) TargetEntryInstr(
-            flow_graph->max_block_id() + 1, block->try_index());
+        TargetEntryInstr* true_target = new (zone)
+            TargetEntryInstr(flow_graph->max_block_id() + 1, block->try_index(),
+                             Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:01]

kNoDeoptId here, because it is overwritten anyway by InheritDeoptTarget.

         true_target->InheritDeoptTarget(zone, join_true);
-        TargetEntryInstr* false_target = new (zone) TargetEntryInstr(
-            flow_graph->max_block_id() + 2, block->try_index());
+        TargetEntryInstr* false_target = new (zone)
+            TargetEntryInstr(flow_graph->max_block_id() + 2, block->try_index(),

[Vyacheslav Egorov (Google), 2017/05/23 12:00:01]

ditto

+                             Thread::Current()->GetNextDeoptId());
         false_target->InheritDeoptTarget(zone, join_false);
         flow_graph->set_max_block_id(flow_graph->max_block_id() + 2);
         *new_branch->true_successor_address() = true_target;
         *new_branch->false_successor_address() = false_target;
-        GotoInstr* goto_true = new (zone) GotoInstr(join_true);
+        GotoInstr* goto_true = new (zone)
+            GotoInstr(join_true, Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:00]

ditto

         goto_true->InheritDeoptTarget(zone, join_true);
         true_target->LinkTo(goto_true);
         true_target->set_last_instruction(goto_true);
-        GotoInstr* goto_false = new (zone) GotoInstr(join_false);
+        GotoInstr* goto_false = new (zone)
+            GotoInstr(join_false, Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:01]

ditto

         goto_false->InheritDeoptTarget(zone, join_false);
         false_target->LinkTo(goto_false);
         false_target->set_last_instruction(goto_false);
@@ -296,7 +302,8 @@ void IfConverter::Simplify(FlowGraph* flow_graph) {
           ComparisonInstr* new_comparison = comparison->CopyWithNewOperands(
               comparison->left()->Copy(zone), comparison->right()->Copy(zone));
           IfThenElseInstr* if_then_else = new (zone) IfThenElseInstr(
-              new_comparison, if_true->Copy(zone), if_false->Copy(zone));
+              new_comparison, if_true->Copy(zone), if_false->Copy(zone),
+              Thread::Current()->GetNextDeoptId());

[Vyacheslav Egorov (Google), 2017/05/23 12:00:00]

I think this should be Thread::kNoDeoptId because below we assign NULL
environment to it anyway.

           flow_graph->InsertBefore(branch, if_then_else, NULL,
                                    FlowGraph::kValue);