[interpreter] Ensure optimizations preserve source positions.

src/interpreter/bytecodes.cc

Index: src/interpreter/bytecodes.cc
diff --git a/src/interpreter/bytecodes.cc b/src/interpreter/bytecodes.cc
index 46134b7f1d418c52dbecbfe82775ad20586f08cf..bce56728f8be9475a03c1f5bb431b4a811114d98 100644
--- a/src/interpreter/bytecodes.cc
+++ b/src/interpreter/bytecodes.cc
@@ -276,6 +276,32 @@ bool Bytecodes::IsAccumulatorLoadWithoutEffects(Bytecode bytecode) {
   }
 }
 
+bool Bytecodes::IsJumpWithoutEffects(Bytecode bytecode) {

[rmcilroy, 2016/06/08 11:31:40]

// static

[oth, 2016/06/08 14:18:25]

Done.

+  return IsJump(bytecode) && !IsJumpIfToBoolean(bytecode);
+}
+

[rmcilroy, 2016/06/08 11:31:40]

// static

[oth, 2016/06/08 14:18:25]

Done.

+bool Bytecodes::IsRegisterLoadWithoutEffects(Bytecode bytecode) {
+  switch (bytecode) {
+    case Bytecode::kMov:
+    case Bytecode::kPopContext:
+    case Bytecode::kPushContext:
+    case Bytecode::kStar:
+    case Bytecode::kLdrUndefined:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// static
+bool Bytecodes::IsWithoutExternalSideEffects(Bytecode bytecode) {
+  // These bytecodes only manipulate interpreter frame state and will
+  // never throw.
+  return (IsAccumulatorLoadWithoutEffects(bytecode) ||
+          IsRegisterLoadWithoutEffects(bytecode) ||
+          bytecode == Bytecode::kNop || IsJumpWithoutEffects(bytecode));
+}
+
 // static
 OperandType Bytecodes::GetOperandType(Bytecode bytecode, int i) {
   DCHECK_LE(bytecode, Bytecode::kLast);
@@ -488,15 +514,6 @@ bool Bytecodes::IsPrefixScalingBytecode(Bytecode bytecode) {
 }
 
 // static
-bool Bytecodes::IsWithoutExternalSideEffects(Bytecode bytecode) {
-  // These bytecodes only manipulate interpreter frame state and will
-  // never throw.
-  return (IsAccumulatorLoadWithoutEffects(bytecode) || IsLdarOrStar(bytecode) ||
-          bytecode == Bytecode::kMov || bytecode == Bytecode::kNop ||
-          IsJump(bytecode));
-}
-
-// static
 bool Bytecodes::IsJumpOrReturn(Bytecode bytecode) {
   return bytecode == Bytecode::kReturn || IsJump(bytecode);
 }