From 9d6f55b08a5a34eac6af3a0b7405d5756628c618 Mon Sep 17 00:00:00 2001
From: mstarzinger <mstarzinger@chromium.org>
Date: Tue, 3 Feb 2015 07:22:41 -0800
Subject: [PATCH] Turn throws into basic block terminators.

R=bmeurer@chromium.org
TEST=cctest/test-run-jsexceptions/Throw

Review URL: https://codereview.chromium.org/896783002

Cr-Commit-Position: refs/heads/master@{#26406}
---
 src/compiler/ast-graph-builder.cc             | 11 ++++-------
 src/compiler/instruction-selector.cc          |  5 +++--
 src/compiler/scheduler.cc                     | 11 +++++++++++
 test/cctest/compiler/test-run-jsexceptions.cc |  1 +
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 7e18fd7..87b0b2d 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -665,8 +665,7 @@ void AstGraphBuilder::ControlScope::PerformCommand(Command command,
     environment()->Drop(current->stack_delta());
     current = current->next_;
   }
-  // TODO(mstarzinger): Unconditionally kill environment once throw is control.
-  if (command != CMD_THROW) builder()->set_environment(env);
+  builder()->set_environment(env);
   DCHECK(current != NULL);  // Always handled (unless stack is malformed).
 }
 
@@ -2792,11 +2791,9 @@ Node* AstGraphBuilder::BuildReturn(Node* return_value) {
 
 
 Node* AstGraphBuilder::BuildThrow(Node* exception_value) {
-  const Operator* op = javascript()->CallRuntime(Runtime::kThrow, 1);
-  Node* control = NewNode(op, exception_value);
-  // TODO(mstarzinger): Thread through the correct bailout id to this point.
-  // PrepareFrameState(value, expr->id(), ast_context()->GetStateCombine());
-  PrepareFrameState(control, BailoutId::None());
+  NewNode(javascript()->CallRuntime(Runtime::kReThrow, 1), exception_value);
+  Node* control = NewNode(common()->Throw(), exception_value);
+  UpdateControlDependencyToLeaveFunction(control);
   return control;
 }
 
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index fe9c287..05d1b21 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -521,7 +521,8 @@ void InstructionSelector::VisitControl(BasicBlock* block) {
       return VisitReturn(value);
     }
     case BasicBlock::kThrow:
-      return VisitThrow(input);
+      DCHECK_EQ(IrOpcode::kThrow, input->opcode());
+      return VisitThrow(input->InputAt(0));
     case BasicBlock::kNone: {
       // TODO(titzer): exit block doesn't have control.
       DCHECK(input == NULL);
@@ -1049,7 +1050,7 @@ void InstructionSelector::VisitReturn(Node* value) {
 
 
 void InstructionSelector::VisitThrow(Node* value) {
-  UNIMPLEMENTED();  // TODO(titzer)
+  Emit(kArchNop, NULL);  // TODO(titzer)
 }
 
 
diff --git a/src/compiler/scheduler.cc b/src/compiler/scheduler.cc
index 70e6547..2e12dd3 100644
--- a/src/compiler/scheduler.cc
+++ b/src/compiler/scheduler.cc
@@ -337,6 +337,10 @@ class CFGBuilder : public ZoneObject {
         scheduler_->UpdatePlacement(node, Scheduler::kFixed);
         ConnectReturn(node);
         break;
+      case IrOpcode::kThrow:
+        scheduler_->UpdatePlacement(node, Scheduler::kFixed);
+        ConnectThrow(node);
+        break;
       default:
         break;
     }
@@ -448,6 +452,13 @@ class CFGBuilder : public ZoneObject {
     schedule_->AddReturn(return_block, ret);
   }
 
+  void ConnectThrow(Node* thr) {
+    Node* throw_block_node = NodeProperties::GetControlInput(thr);
+    BasicBlock* throw_block = schedule_->block(throw_block_node);
+    TraceConnect(thr, throw_block, NULL);
+    schedule_->AddThrow(throw_block, thr);
+  }
+
   void TraceConnect(Node* node, BasicBlock* block, BasicBlock* succ) {
     DCHECK(block);
     if (succ == NULL) {
diff --git a/test/cctest/compiler/test-run-jsexceptions.cc b/test/cctest/compiler/test-run-jsexceptions.cc
index 43ce91b..74990da 100644
--- a/test/cctest/compiler/test-run-jsexceptions.cc
+++ b/test/cctest/compiler/test-run-jsexceptions.cc
@@ -10,6 +10,7 @@ using namespace v8::internal;
 using namespace v8::internal::compiler;
 
 TEST(Throw) {
+  i::FLAG_turbo_exceptions = true;
   FunctionTester T("(function(a,b) { if (a) { throw b; } else { return b; }})");
 
   T.CheckThrows(T.true_value(), T.NewObject("new Error"));
-- 
2.7.4