[turbofan] Preserve pending message while inside finally-block.

This makes sure that any pending message is saved before entering
and restored after exiting a finally block. It also makes sure that
operand stacks are kept in sync to full-codegen.

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

Review URL: https://codereview.chromium.org/979173002

Cr-Commit-Position: refs/heads/master@{#27036}

src/compiler/ast-graph-builder.cc

@@ -1252,6 +1252,13 @@ void AstGraphBuilder::VisitTryCatchStatement(TryCatchStatement* stmt) {
 void AstGraphBuilder::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   TryFinallyBuilder try_control(this);
 
+  ExternalReference message_object =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  ExternalReference message_present =
+      ExternalReference::address_of_has_pending_message(isolate());
+  ExternalReference message_script =
+      ExternalReference::address_of_pending_message_script(isolate());
+
   // We keep a record of all paths that enter the finally-block to be able to
   // dispatch to the correct continuation point after the statements in the
   // finally-block have been evaluated.
@@ -1280,23 +1287,29 @@ void AstGraphBuilder::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   //  - BreakStatement/ContinueStatement: Filled with the hole.
   //  - Falling through into finally-block: Filled with the hole.
   Node* result = try_control.GetResultValueNode();
+  Node* token = try_control.GetDispatchTokenNode();
 
-  // TODO(mstarzinger): See FullCodeGenerator::EnterFinallyBlock.
+  // The result value, dispatch token and message is expected on the operand
-  environment()->Push(jsgraph()->SmiConstant(Code::kHeaderSize));
+  // stack (this is in sync with FullCodeGenerator::EnterFinallyBlock).
+  environment()->Push(token);  // TODO(mstarzinger): Cook token!
   environment()->Push(result);
-  environment()->Push(jsgraph()->TheHoleConstant());  // pending_message_obj
+  environment()->Push(BuildLoadExternal(message_object, kMachAnyTagged));
-  environment()->Push(jsgraph()->SmiConstant(0));     // has_pending_message
+  environment()->Push(BuildLoadExternal(message_present, kMachBool));
-  environment()->Push(jsgraph()->TheHoleConstant());  // pending_message_script
+  environment()->Push(BuildLoadExternal(message_script, kMachAnyTagged));
 
   // Evaluate the finally-block.
   Visit(stmt->finally_block());
   try_control.EndFinally();
 
-  // TODO(mstarzinger): See FullCodeGenerator::ExitFinallyBlock.
+  // The result value, dispatch token and message is restored from the operand
-  environment()->Drop(5);
+  // stack (this is in sync with FullCodeGenerator::ExitFinallyBlock).
+  BuildStoreExternal(message_script, kMachAnyTagged, environment()->Pop());
+  BuildStoreExternal(message_present, kMachBool, environment()->Pop());
+  BuildStoreExternal(message_object, kMachAnyTagged, environment()->Pop());
+  result = environment()->Pop();
+  token = environment()->Pop();  // TODO(mstarzinger): Uncook token!
 
   // Dynamic dispatch after the finally-block.
-  Node* token = try_control.GetDispatchTokenNode();
   commands->ApplyDeferredCommands(token, result);
 
   // TODO(mstarzinger): Remove bailout once everything works.
@@ -2776,9 +2789,8 @@ Node* AstGraphBuilder::BuildVariableAssignment(
 
 
 Node* AstGraphBuilder::BuildLoadObjectField(Node* object, int offset) {
-  Node* field_load = NewNode(jsgraph()->machine()->Load(kMachAnyTagged), object,
+  return NewNode(jsgraph()->machine()->Load(kMachAnyTagged), object,
-                             jsgraph()->Int32Constant(offset - kHeapObjectTag));
+                 jsgraph()->IntPtrConstant(offset - kHeapObjectTag));
-  return field_load;
 }
 
 
@@ -2805,6 +2817,23 @@ Node* AstGraphBuilder::BuildLoadGlobalProxy() {
 }
 
 
+Node* AstGraphBuilder::BuildLoadExternal(ExternalReference reference,
+                                         MachineType type) {
+  return NewNode(jsgraph()->machine()->Load(type),
+                 jsgraph()->ExternalConstant(reference),
+                 jsgraph()->IntPtrConstant(0));
+}
+
+
+Node* AstGraphBuilder::BuildStoreExternal(ExternalReference reference,
+                                          MachineType type, Node* value) {
+  StoreRepresentation representation(type, kNoWriteBarrier);
+  return NewNode(jsgraph()->machine()->Store(representation),
+                 jsgraph()->ExternalConstant(reference),
+                 jsgraph()->IntPtrConstant(0), value);
+}
+
+
 Node* AstGraphBuilder::BuildToBoolean(Node* input) {
   // TODO(titzer): This should be in a JSOperatorReducer.
   switch (input->opcode()) {
@@ -2940,11 +2969,8 @@ Node* AstGraphBuilder::BuildBinaryOp(Node* left, Node* right, Token::Value op) {
 
 Node* AstGraphBuilder::BuildStackCheck() {
   IfBuilder stack_check(this);
-  Node* limit =
+  Node* limit = BuildLoadExternal(
-      NewNode(jsgraph()->machine()->Load(kMachPtr),
+      ExternalReference::address_of_stack_limit(isolate()), kMachPtr);
-              jsgraph()->ExternalConstant(
-                  ExternalReference::address_of_stack_limit(isolate())),
-              jsgraph()->ZeroConstant());
   Node* stack = NewNode(jsgraph()->machine()->LoadStackPointer());
   Node* tag = NewNode(jsgraph()->machine()->UintLessThan(), limit, stack);
   stack_check.If(tag, BranchHint::kTrue);

src/compiler/ast-graph-builder.h

@@ -231,6 +231,10 @@ class AstGraphBuilder : public AstVisitor {
   Node* BuildLoadClosure();
   Node* BuildLoadObjectField(Node* object, int offset);
 
+  // Builders for accessing external references.
+  Node* BuildLoadExternal(ExternalReference ref, MachineType type);
+  Node* BuildStoreExternal(ExternalReference ref, MachineType type, Node* val);
+
   // Builders for automatic type conversion.
   Node* BuildToBoolean(Node* value);
   Node* BuildToName(Node* value, BailoutId bailout_id);

src/compiler/simplified-lowering.cc

@@ -916,7 +916,7 @@ class RepresentationSelector {
         MachineTypeUnion tBase = kRepTagged | kMachPtr;
         LoadRepresentation rep = OpParameter<LoadRepresentation>(node);
         ProcessInput(node, 0, tBase);   // pointer or object
-        ProcessInput(node, 1, kMachInt32);  // index
+        ProcessInput(node, 1, kMachIntPtr);  // index
         ProcessRemainingInputs(node, 2);
         SetOutput(node, rep);
         break;
@@ -926,7 +926,7 @@ class RepresentationSelector {
         MachineTypeUnion tBase = kRepTagged | kMachPtr;
         StoreRepresentation rep = OpParameter<StoreRepresentation>(node);
         ProcessInput(node, 0, tBase);   // pointer or object
-        ProcessInput(node, 1, kMachInt32);  // index
+        ProcessInput(node, 1, kMachIntPtr);  // index
         ProcessInput(node, 2, rep.machine_type());
         ProcessRemainingInputs(node, 3);
         SetOutput(node, 0);

test/cctest/compiler/test-run-jsexceptions.cc

@@ -18,7 +18,7 @@ TEST(Throw) {
 }
 
 
-TEST(ThrowSourcePosition) {
+TEST(ThrowMessagePosition) {
   i::FLAG_turbo_exceptions = true;
   static const char* src =
       "(function(a, b) {        \n"
@@ -47,6 +47,48 @@ TEST(ThrowSourcePosition) {
 }
 
 
+TEST(ThrowMessageDirectly) {
+  i::FLAG_turbo_exceptions = true;
+  static const char* src =
+      "(function(a, b) {"
+      "  if (a) { throw b; } else { throw new Error(b); }"
+      "})";
+  FunctionTester T(src);
+  v8::Handle<v8::Message> message;
+
+  message = T.CheckThrowsReturnMessage(T.false_value(), T.Val("Wat?"));
+  CHECK(!message.IsEmpty());
+  CHECK(message->Get()->Equals(v8_str("Uncaught Error: Wat?")));
+
+  message = T.CheckThrowsReturnMessage(T.true_value(), T.Val("Kaboom!"));
+  CHECK(!message.IsEmpty());
+  CHECK(message->Get()->Equals(v8_str("Uncaught Kaboom!")));
+}
+
+
+TEST(ThrowMessageIndirectly) {
+  i::FLAG_turbo_exceptions = true;
+  static const char* src =
+      "(function(a, b) {"
+      "  try {"
+      "    if (a) { throw b; } else { throw new Error(b); }"
+      "  } finally {"
+      "    try { throw 'clobber'; } catch (e) { 'unclobber'; }"
+      "  }"
+      "})";
+  FunctionTester T(src);
+  v8::Handle<v8::Message> message;
+
+  message = T.CheckThrowsReturnMessage(T.false_value(), T.Val("Wat?"));
+  CHECK(!message.IsEmpty());
+  CHECK(message->Get()->Equals(v8_str("Uncaught Error: Wat?")));
+
+  message = T.CheckThrowsReturnMessage(T.true_value(), T.Val("Kaboom!"));
+  CHECK(!message.IsEmpty());
+  CHECK(message->Get()->Equals(v8_str("Uncaught Kaboom!")));
+}
+
+
 // TODO(mstarzinger): Increase test coverage by having similar tests within the
 // mjsunit suite to also test integration with other components (e.g. OSR).