Find the last outer eval scope to check in fullcodegen rather than scope analysis

src/full-codegen/x64/full-codegen-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 1118 matching lines @@
   CallStoreIC();
 }
 
 
 void FullCodeGenerator::EmitLoadGlobalCheckExtensions(VariableProxy* proxy,
                                                       TypeofMode typeof_mode,
                                                       Label* slow) {
   Register context = rsi;
   Register temp = rdx;
 
-  Scope* s = scope();
-  while (s != NULL) {
-    if (s->num_heap_slots() > 0) {
-      if (s->calls_sloppy_eval()) {
-        // Check that extension is "the hole".
-        __ JumpIfNotRoot(ContextOperand(context, Context::EXTENSION_INDEX),
-                         Heap::kTheHoleValueRootIndex, slow);
-      }
-      // Load next context in chain.
-      __ movp(temp, ContextOperand(context, Context::PREVIOUS_INDEX));
-      // Walk the rest of the chain without clobbering rsi.
-      context = temp;
+  int to_check = scope()->ContextChainLengthUntilOutermostSloppyEval();
+  for (Scope* s = scope(); to_check > 0; s = s->outer_scope()) {
+    if (!s->NeedsContext()) continue;
+    if (s->calls_sloppy_eval()) {
+      // Check that extension is "the hole".
+      __ JumpIfNotRoot(ContextOperand(context, Context::EXTENSION_INDEX),
+                       Heap::kTheHoleValueRootIndex, slow);
     }
-    // If no outer scope calls eval, we do not need to check more
-    // context extensions.
-    if (!s->outer_scope_calls_sloppy_eval()) break;
-    s = s->outer_scope();
+    // Load next context in chain.
+    __ movp(temp, ContextOperand(context, Context::PREVIOUS_INDEX));
+    // Walk the rest of the chain without clobbering rsi.
+    context = temp;
+    to_check--;
   }
 
   // All extension objects were empty and it is safe to use a normal global
   // load machinery.
   EmitGlobalVariableLoad(proxy, typeof_mode);
 }
 
 
 MemOperand FullCodeGenerator::ContextSlotOperandCheckExtensions(Variable* var,
                                                                 Label* slow) {
@@ skipping 2474 matching lines @@
   DCHECK_EQ(
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64