[interpreter] Fix label binding for unreached labels.

src/interpreter/bytecode-array-builder.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-array-builder.h"
 #include "src/compiler.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
@@ skipping 702 matching lines @@
   label->bind_to(bytecodes()->size());
   LeaveBasicBlock();
   return *this;
 }
 
 
 BytecodeArrayBuilder& BytecodeArrayBuilder::Bind(const BytecodeLabel& target,
                                                  BytecodeLabel* label) {
   DCHECK(!label->is_bound());
   DCHECK(target.is_bound());
-  PatchJump(bytecodes()->begin() + target.offset(),
-            bytecodes()->begin() + label->offset());
+  if (label->is_forward_target()) {
+    // An earlier jump instruction refers to this label. Update it's location.
+    PatchJump(bytecodes()->begin() + target.offset(),
+              bytecodes()->begin() + label->offset());
+    // Now treat as if the label will only be back referred to.
+  }
   label->bind_to(target.offset());
   LeaveBasicBlock();
   return *this;
 }
 
 
 // static
 Bytecode BytecodeArrayBuilder::GetJumpWithConstantOperand(
     Bytecode jump_bytecode) {
   switch (jump_bytecode) {
@@ skipping 899 matching lines @@
 }
 
 // static
 bool BytecodeArrayBuilder::FitsInReg16OperandUntranslated(Register value) {
   return value.is_short_operand();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8