Make sure exception handlers are deferred.

R=bmeurer@chromium.org
TEST=unittests/SchedulerTest.CallException

Review URL: https://codereview.chromium.org/944903002

Cr-Commit-Position: refs/heads/master@{#26816}

src/compiler/scheduler.cc

@@ -1073,6 +1073,7 @@ void Scheduler::PropagateImmediateDominators(BasicBlock* block) {
     auto end = block->predecessors().end();
     DCHECK(pred != end);  // All blocks except start have predecessors.
     BasicBlock* dominator = *pred;
+    bool deferred = dominator->deferred();
     // For multiple predecessors, walk up the dominator tree until a common
     // dominator is found. Visitation order guarantees that all predecessors
     // except for backwards edges have been visited.
@@ -1080,11 +1081,11 @@ void Scheduler::PropagateImmediateDominators(BasicBlock* block) {
       // Don't examine backwards edges.
       if ((*pred)->dominator_depth() < 0) continue;
       dominator = BasicBlock::GetCommonDominator(dominator, *pred);
+      deferred = deferred & (*pred)->deferred();
     }
     block->set_dominator(dominator);
     block->set_dominator_depth(dominator->dominator_depth() + 1);
-    // Propagate "deferredness" of the dominator.
-    if (dominator->deferred()) block->set_deferred(true);
+    block->set_deferred(deferred | block->deferred());
     Trace("Block B%d's idom is B%d, depth = %d\n", block->id().ToInt(),
           dominator->id().ToInt(), block->dominator_depth());
   }

test/unittests/compiler/scheduler-unittest.cc

@@ -136,6 +136,8 @@ const Operator kHeapConstant(IrOpcode::kHeapConstant, Operator::kPure,
                              "HeapConstant", 0, 0, 0, 1, 0, 0);
 const Operator kIntAdd(IrOpcode::kInt32Add, Operator::kPure, "Int32Add", 2, 0,
                        0, 1, 0, 0);
+const Operator kMockCall(IrOpcode::kCall, Operator::kNoProperties, "MockCall",
+                         0, 0, 1, 1, 0, 2);
 
 }  // namespace
 
@@ -1962,6 +1964,34 @@ TARGET_TEST_F(SchedulerTest, BranchHintFalse) {
 }
 
 
+TARGET_TEST_F(SchedulerTest, CallException) {
+  Node* start = graph()->NewNode(common()->Start(1));
+  graph()->SetStart(start);
+
+  Node* p0 = graph()->NewNode(common()->Parameter(0), start);
+  Node* c1 = graph()->NewNode(&kMockCall, start);
+  Node* ok1 = graph()->NewNode(common()->IfSuccess(), c1);
+  Node* ex1 = graph()->NewNode(common()->IfException(), c1);
+  Node* c2 = graph()->NewNode(&kMockCall, ok1);
+  Node* ok2 = graph()->NewNode(common()->IfSuccess(), c2);
+  Node* ex2 = graph()->NewNode(common()->IfException(), c2);
+  Node* hdl = graph()->NewNode(common()->Merge(2), ex1, ex2);
+  Node* m = graph()->NewNode(common()->Merge(2), ok2, hdl);
+  Node* phi = graph()->NewNode(common()->Phi(kMachAnyTagged, 2), c2, p0, m);
+  Node* ret = graph()->NewNode(common()->Return(), phi, start, m);
+  Node* end = graph()->NewNode(common()->End(), ret);
+
+  graph()->SetEnd(end);
+
+  Schedule* schedule = ComputeAndVerifySchedule(17);
+  // Make sure the exception blocks as well as the handler are deferred.
+  EXPECT_TRUE(schedule->block(ex1)->deferred());
+  EXPECT_TRUE(schedule->block(ex2)->deferred());
+  EXPECT_TRUE(schedule->block(hdl)->deferred());
+  EXPECT_FALSE(schedule->block(m)->deferred());
+}
+
+
 TARGET_TEST_F(SchedulerTest, Switch) {
   Node* start = graph()->NewNode(common()->Start(1));
   graph()->SetStart(start);