Model exceptional edges from call nodes in TurboFan.

src/compiler/scheduler.cc

Index: src/compiler/scheduler.cc
diff --git a/src/compiler/scheduler.cc b/src/compiler/scheduler.cc
index 25bdba4961cc6c79fb39d716859dceccc301dc62..6b06342e449a34b188f50166ba76c9bccb1c4990 100644
--- a/src/compiler/scheduler.cc
+++ b/src/compiler/scheduler.cc
@@ -286,7 +286,7 @@ class CFGBuilder : public ZoneObject {
   }
 
  private:
-  // TODO(mstarzinger): Only for Scheduler::FuseFloatingControl.
+  friend class ScheduleLateNodeVisitor;
   friend class Scheduler;
 
   void FixNode(BasicBlock* block, Node* node) {
@@ -320,6 +320,10 @@ class CFGBuilder : public ZoneObject {
       case IrOpcode::kSwitch:
         BuildBlocksForSuccessors(node);
         break;
+      case IrOpcode::kCall:
+        if (!IsExceptionalCall(node)) break;
+        BuildBlocksForSuccessors(node);
+        break;
       default:
         break;
     }
@@ -347,6 +351,11 @@ class CFGBuilder : public ZoneObject {
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectThrow(node);
         break;
+      case IrOpcode::kCall:
+        if (!IsExceptionalCall(node)) break;
+        scheduler_->UpdatePlacement(node, Scheduler::kFixed);
+        ConnectCall(node);
+        break;
       default:
         break;
     }
@@ -373,19 +382,16 @@ class CFGBuilder : public ZoneObject {
   }
 
   // Collect the branch-related projections from a node, such as IfTrue,
-  // IfFalse, and Case.
+  // IfFalse, IfException, IfSuccess, and Case.
   void CollectSuccessorProjections(Node* node, Node** successors,
                                    size_t successor_count) {
 #ifdef DEBUG
-    DCHECK_EQ(static_cast<int>(successor_count), node->UseCount());
+    DCHECK_LE(static_cast<int>(successor_count), node->UseCount());
     std::memset(successors, 0, sizeof(*successors) * successor_count);
 #endif
     for (Node* const use : node->uses()) {
       size_t index;
       switch (use->opcode()) {
-        default:
-          UNREACHABLE();
-        // Fall through.
         case IrOpcode::kIfTrue:
           DCHECK_EQ(IrOpcode::kBranch, node->opcode());
           index = 0;
@@ -394,10 +400,20 @@ class CFGBuilder : public ZoneObject {
           DCHECK_EQ(IrOpcode::kBranch, node->opcode());
           index = 1;
           break;
+        case IrOpcode::kIfException:
+          DCHECK_EQ(IrOpcode::kCall, node->opcode());
+          index = 1;
+          break;
+        case IrOpcode::kIfSuccess:
+          DCHECK_EQ(IrOpcode::kCall, node->opcode());
+          index = 0;
+          break;
         case IrOpcode::kCase:
           DCHECK_EQ(IrOpcode::kSwitch, node->opcode());
           index = CaseIndexOf(use->op());
           break;
+        default:
+          continue;
       }
       DCHECK_LT(index, successor_count);
       DCHECK(successors[index] == nullptr);
@@ -419,6 +435,31 @@ class CFGBuilder : public ZoneObject {
     }
   }
 
+  BasicBlock* FindPredecessorBlock(Node* node) {
+    BasicBlock* predecessor_block = nullptr;
+    while (predecessor_block == nullptr) {

[Benedikt Meurer, 2015/02/17 05:58:49]

The condition is redundant; can be while(true) instead.

[Michael Starzinger, 2015/02/17 10:12:06]

Done.

+      predecessor_block = schedule_->block(node);
+      if (predecessor_block != nullptr) break;
+      node = NodeProperties::GetControlInput(node);
+    }
+    return predecessor_block;
+  }
+
+  void ConnectCall(Node* call) {
+    BasicBlock* successor_blocks[2];
+    CollectSuccessorBlocks(call, successor_blocks, arraysize(successor_blocks));
+
+    // Consider the exception continuation to be deferred.
+    successor_blocks[1]->set_deferred(true);
+
+    Node* call_control = NodeProperties::GetControlInput(call);
+    BasicBlock* call_block = FindPredecessorBlock(call_control);
+    TraceConnect(call, call_block, successor_blocks[0]);
+    TraceConnect(call, call_block, successor_blocks[1]);
+    schedule_->AddCall(call_block, call, successor_blocks[0],
+                       successor_blocks[1]);
+  }
+
   void ConnectBranch(Node* branch) {
     BasicBlock* successor_blocks[2];
     CollectSuccessorBlocks(branch, successor_blocks,
@@ -442,10 +483,8 @@ class CFGBuilder : public ZoneObject {
       schedule_->InsertBranch(component_start_, component_end_, branch,
                               successor_blocks[0], successor_blocks[1]);
     } else {
-      Node* branch_block_node = NodeProperties::GetControlInput(branch);
-      BasicBlock* branch_block = schedule_->block(branch_block_node);
-      DCHECK_NOT_NULL(branch_block);
-
+      Node* branch_control = NodeProperties::GetControlInput(branch);
+      BasicBlock* branch_block = FindPredecessorBlock(branch_control);
       TraceConnect(branch, branch_block, successor_blocks[0]);
       TraceConnect(branch, branch_block, successor_blocks[1]);
       schedule_->AddBranch(branch_block, branch, successor_blocks[0],
@@ -466,14 +505,12 @@ class CFGBuilder : public ZoneObject {
       schedule_->InsertSwitch(component_start_, component_end_, sw,
                               successor_blocks, successor_count);
     } else {
-      Node* sw_block_node = NodeProperties::GetControlInput(sw);
-      BasicBlock* sw_block = schedule_->block(sw_block_node);
-      DCHECK_NOT_NULL(sw_block);
-
+      Node* switch_control = NodeProperties::GetControlInput(sw);
+      BasicBlock* switch_block = FindPredecessorBlock(switch_control);
       for (size_t index = 0; index < successor_count; ++index) {
-        TraceConnect(sw, sw_block, successor_blocks[index]);
+        TraceConnect(sw, switch_block, successor_blocks[index]);
       }
-      schedule_->AddSwitch(sw_block, sw, successor_blocks, successor_count);
+      schedule_->AddSwitch(switch_block, sw, successor_blocks, successor_count);
     }
   }
 
@@ -486,22 +523,22 @@ class CFGBuilder : public ZoneObject {
     // For all of the merge's control inputs, add a goto at the end to the
     // merge's basic block.
     for (Node* const input : merge->inputs()) {
-      BasicBlock* predecessor_block = schedule_->block(input);
+      BasicBlock* predecessor_block = FindPredecessorBlock(input);
       TraceConnect(merge, predecessor_block, block);
       schedule_->AddGoto(predecessor_block, block);
     }
   }
 
   void ConnectReturn(Node* ret) {
-    Node* return_block_node = NodeProperties::GetControlInput(ret);
-    BasicBlock* return_block = schedule_->block(return_block_node);
+    Node* return_control = NodeProperties::GetControlInput(ret);
+    BasicBlock* return_block = FindPredecessorBlock(return_control);
     TraceConnect(ret, return_block, NULL);
     schedule_->AddReturn(return_block, ret);
   }
 
   void ConnectThrow(Node* thr) {
-    Node* throw_block_node = NodeProperties::GetControlInput(thr);
-    BasicBlock* throw_block = schedule_->block(throw_block_node);
+    Node* throw_control = NodeProperties::GetControlInput(thr);
+    BasicBlock* throw_block = FindPredecessorBlock(throw_control);
     TraceConnect(thr, throw_block, NULL);
     schedule_->AddThrow(throw_block, thr);
   }
@@ -517,6 +554,13 @@ class CFGBuilder : public ZoneObject {
     }
   }
 
+  bool IsExceptionalCall(Node* node) {
+    for (Node* const use : node->uses()) {
+      if (use->opcode() == IrOpcode::kIfException) return true;
+    }
+    return false;
+  }
+
   bool IsFinalMerge(Node* node) {
     return (node->opcode() == IrOpcode::kMerge &&
             node == scheduler_->graph_->end()->InputAt(0));
@@ -1362,7 +1406,7 @@ class ScheduleLateNodeVisitor {
     }
 
     // Schedule the node or a floating control structure.
-    if (NodeProperties::IsControl(node)) {
+    if (IrOpcode::IsMergeOpcode(node->opcode())) {
       ScheduleFloatingControl(block, node);
     } else {
       ScheduleNode(block, node);
@@ -1486,10 +1530,13 @@ class ScheduleLateNodeVisitor {
     return block;
   }
 
+  BasicBlock* FindPredecessorBlock(Node* node) {
+    return scheduler_->control_flow_builder_->FindPredecessorBlock(node);
+  }
+
   BasicBlock* GetBlockForUse(Edge edge) {
     Node* use = edge.from();
-    IrOpcode::Value opcode = use->opcode();
-    if (IrOpcode::IsPhiOpcode(opcode)) {
+    if (IrOpcode::IsPhiOpcode(use->opcode())) {
       // If the use is from a coupled (i.e. floating) phi, compute the common
       // dominator of its uses. This will not recurse more than one level.
       if (scheduler_->GetPlacement(use) == Scheduler::kCoupled) {
@@ -1498,15 +1545,23 @@ class ScheduleLateNodeVisitor {
         DCHECK_EQ(edge.to(), NodeProperties::GetControlInput(use));
         return GetCommonDominatorOfUses(use);
       }
-      // If the use is from a fixed (i.e. non-floating) phi, use the block
-      // of the corresponding control input to the merge.
+      // If the use is from a fixed (i.e. non-floating) phi, we use the
+      // predecessor block of the corresponding control input to the merge.
       if (scheduler_->GetPlacement(use) == Scheduler::kFixed) {
         Trace("  input@%d into a fixed phi #%d:%s\n", edge.index(), use->id(),
               use->op()->mnemonic());
         Node* merge = NodeProperties::GetControlInput(use, 0);
-        opcode = merge->opcode();
-        DCHECK(opcode == IrOpcode::kMerge || opcode == IrOpcode::kLoop);
-        use = NodeProperties::GetControlInput(merge, edge.index());
+        DCHECK(IrOpcode::IsMergeOpcode(merge->opcode()));
+        Node* input = NodeProperties::GetControlInput(merge, edge.index());
+        return FindPredecessorBlock(input);
+      }
+    } else if (IrOpcode::IsMergeOpcode(use->opcode())) {
+      // If the use is from a fixed (i.e. non-floating) merge, we use the
+      // predecessor block of the current input to the merge.
+      if (scheduler_->GetPlacement(use) == Scheduler::kFixed) {
+        Trace("  input@%d into a fixed merge #%d:%s\n", edge.index(), use->id(),
+              use->op()->mnemonic());
+        return FindPredecessorBlock(edge.to());
       }
     }
     BasicBlock* result = schedule_->block(use);