[Interpreter] Marks that 'throw' has returned a value.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 391 matching lines @@
   // Build assignment to {new.target} variable if it is used.
   VisitNewTargetVariable(scope()->new_target_var());
 
   // TODO(rmcilroy): Emit tracing call if requested to do so.
   if (FLAG_trace) {
     UNIMPLEMENTED();
   }
 
   // Visit illegal re-declaration and bail out if it exists.
   if (scope()->HasIllegalRedeclaration()) {
-    Visit(scope()->GetIllegalRedeclaration());
+    VisitForEffect(scope()->GetIllegalRedeclaration());

[mythria, 2016/01/19 10:48:04]

GetIllegalRedeclaration is an expression, so I added a visitForEffect instead of
visit. Otherwise, we will not have an ExpressionResultScope when we visit throw
from here. 

[rmcilroy, 2016/01/19 11:45:55]

SGTM

[Michael Starzinger, 2016/01/19 11:45:59]

Acknowledged.

     return;
   }
 
   // Visit declarations within the function scope.
   VisitDeclarations(scope()->declarations());
 
   // Visit statements in the function body.
   VisitStatements(info()->literal()->body());
 }
 
@@ skipping 1050 matching lines @@
   execution_result()->SetResultInAccumulator();
 }
 
 
 void BytecodeGenerator::VisitYield(Yield* expr) { UNIMPLEMENTED(); }
 
 
 void BytecodeGenerator::VisitThrow(Throw* expr) {
   VisitForAccumulatorValue(expr->exception());
   builder()->Throw();
+  // Throw statments are modeled as expression instead of statments. These are
+  // converted to assignment statements in Rewriter::ReWrite pass. An

[Michael Starzinger, 2016/01/19 11:45:59]

nit: s/to/from/

[mythria, 2016/01/20 13:45:10]

Done.

+  // assignment statement expects a value in the accumulator. This is a hack to
+  // avoid DCHECK fails assert accumulator has been set.
+  execution_result()->SetResultInAccumulator();
 }
 
 
 void BytecodeGenerator::VisitPropertyLoad(Register obj, Property* expr) {
   LhsKind property_kind = Property::GetAssignType(expr);
   FeedbackVectorSlot slot = expr->PropertyFeedbackSlot();
   switch (property_kind) {
     case VARIABLE:
       UNREACHABLE();
     case NAMED_PROPERTY: {
@@ skipping 723 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8