Use a different map to distinguish eval contexts

src/crankshaft/x64/lithium-codegen-x64.cc

Index: src/crankshaft/x64/lithium-codegen-x64.cc
diff --git a/src/crankshaft/x64/lithium-codegen-x64.cc b/src/crankshaft/x64/lithium-codegen-x64.cc
index 60d00927d093f438b55adb3be48ff60379d8c2ca..0a9e2302c8ae91bbb7143e7bfa98aca76e2f00f7 100644
--- a/src/crankshaft/x64/lithium-codegen-x64.cc
+++ b/src/crankshaft/x64/lithium-codegen-x64.cc
@@ -180,14 +180,22 @@ void LCodeGen::DoPrologue(LPrologue* instr) {
       deopt_mode = Safepoint::kLazyDeopt;
     } else {
       if (slots <= FastNewFunctionContextStub::kMaximumSlots) {
-        FastNewFunctionContextStub stub(isolate());
-        __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
-        __ CallStub(&stub);
+        if (info()->scope()->is_eval_scope()) {
+          FastNewEvalContextStub stub(isolate());
+          __ Set(FastNewEvalContextDescriptor::SlotsRegister(), slots);
+          __ CallStub(&stub);
+        } else {
+          FastNewFunctionContextStub stub(isolate());
+          __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
+          __ CallStub(&stub);
+        }
         // Result of FastNewFunctionContextStub is always in new space.
         need_write_barrier = false;
       } else {
         __ Push(rdi);
-        __ CallRuntime(Runtime::kNewFunctionContext);
+        __ CallRuntime(info()->scope()->is_eval_scope()
+                           ? Runtime::kNewEvalContext
+                           : Runtime::kNewFunctionContext);
       }
     }
     RecordSafepoint(deopt_mode);