[compiler] Compare handles by location only.

This is in preparation for running code generation off the main thread.

Bug: v8:6048
Change-Id: Ic1ddcbbb8995d49dfcef1ffbf135117291a00ea7
Reviewed-on: https://chromium-review.googlesource.com/505513Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45334}

src/compiler/code-generator.cc

@@ -99,7 +99,7 @@ Handle<Code> CodeGenerator::GenerateCode() {
   DCHECK_EQ(0u, deoptimization_literals_.size());
   for (CompilationInfo::InlinedFunctionHolder& inlined :
        info->inlined_functions()) {
-    if (!inlined.shared_info.is_identical_to(info->shared_info())) {
+    if (!inlined.shared_info.equals(info->shared_info())) {
       int index = DefineDeoptimizationLiteral(inlined.shared_info);
       inlined.RegisterInlinedFunctionId(index);
     }
@@ -110,7 +110,7 @@ Handle<Code> CodeGenerator::GenerateCode() {
   // functions. This ensures unoptimized code is kept alive by optimized code.
   for (const CompilationInfo::InlinedFunctionHolder& inlined :
        info->inlined_functions()) {
-    if (!inlined.shared_info.is_identical_to(info->shared_info())) {
+    if (!inlined.shared_info.equals(info->shared_info())) {
       DefineDeoptimizationLiteral(inlined.inlined_code_object_root);
     }
   }
@@ -660,7 +660,7 @@ void CodeGenerator::RecordCallPosition(Instruction* instr) {
 int CodeGenerator::DefineDeoptimizationLiteral(Handle<Object> literal) {
   int result = static_cast<int>(deoptimization_literals_.size());
   for (unsigned i = 0; i < deoptimization_literals_.size(); ++i) {
-    if (deoptimization_literals_[i].is_identical_to(literal)) return i;
+    if (deoptimization_literals_[i].equals(literal)) return i;
   }
   deoptimization_literals_.push_back(literal);
   return result;
@@ -970,7 +970,7 @@ void CodeGenerator::AddTranslationForOperand(Translation* translation,
       default:
         UNREACHABLE();
     }
-    if (constant_object.is_identical_to(info()->closure())) {
+    if (constant_object.equals(info()->closure())) {
       translation->StoreJSFrameFunction();
     } else {
       int literal_id = DefineDeoptimizationLiteral(constant_object);

src/handles.h

@@ -133,10 +133,13 @@ class Handle final : public HandleBase {
   // MaybeHandle to force validation before being used as handles.
   static const Handle<T> null() { return Handle<T>(); }
 
+  // Location equality.
+  bool equals(Handle<T> other) const { return address() == other.address(); }
+
   // Provide function object for location equality comparison.
   struct equal_to : public std::binary_function<Handle<T>, Handle<T>, bool> {
     V8_INLINE bool operator()(Handle<T> lhs, Handle<T> rhs) const {
-      return lhs.address() == rhs.address();
+      return lhs.equals(rhs);
     }
   };