[turbofan] Correctly handle illegal redeclarations.

R=titzer@chromium.org
TEST=mjsunit/const-redecl

Review URL: https://codereview.chromium.org/1115613002

Cr-Commit-Position: refs/heads/master@{#28125}

src/compiler.cc

@@ -348,10 +348,6 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
     return AbortOptimization(kTooManyParametersLocals);
   }
 
-  if (scope->HasIllegalRedeclaration()) {
-    return AbortOptimization(kFunctionWithIllegalRedeclaration);
-  }
-
   // Check the whitelist for Crankshaft.
   if (!info()->closure()->PassesFilter(FLAG_hydrogen_filter)) {
     return AbortOptimization(kHydrogenFilter);
@@ -409,6 +405,11 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
   // Do not use Crankshaft if the code is intended to be serialized.
   if (!isolate()->use_crankshaft()) return SetLastStatus(FAILED);
 
+  if (scope->HasIllegalRedeclaration()) {
+    // Crankshaft cannot handle illegal redeclarations.
+    return AbortOptimization(kFunctionWithIllegalRedeclaration);
+  }
+
   if (FLAG_trace_opt) {
     OFStream os(stdout);
     os << "[compiling method " << Brief(*info()->closure())

src/compiler/ast-graph-builder.cc

@@ -514,6 +514,13 @@ void AstGraphBuilder::CreateGraphBody(bool stack_check) {
     NewNode(javascript()->CallRuntime(Runtime::kTraceEnter, 0));
   }
 
+  // Visit illegal re-declaration and bail out if it exists.
+  if (scope->HasIllegalRedeclaration()) {
+    AstEffectContext for_effect(this);
+    scope->VisitIllegalRedeclaration(this);
+    return;
+  }
+
   // Visit implicit declaration of the function name.
   if (scope->is_function_scope() && scope->function() != NULL) {
     VisitVariableDeclaration(scope->function());