[runtime] Refactor Object::Equals to make exception cases explicit.

src/objects.cc

 // Copyright 2013 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.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 273 matching lines @@
 Maybe<bool> Object::Equals(Handle<Object> x, Handle<Object> y) {
   while (true) {
     if (x->IsNumber()) {
       if (y->IsNumber()) {
         return Just(NumberEquals(x, y));
       } else if (y->IsBoolean()) {
         return Just(NumberEquals(*x, Handle<Oddball>::cast(y)->to_number()));
       } else if (y->IsString()) {
         return Just(NumberEquals(x, String::ToNumber(Handle<String>::cast(y))));
       } else if (y->IsJSReceiver() && !y->IsUndetectableObject()) {
-        if (JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y)).ToHandle(&y)) {
-          continue;
-        } else {
+        if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y))
+                 .ToHandle(&y)) {
           return Nothing<bool>();
         }
       } else {
         return Just(false);
       }
     } else if (x->IsString()) {
       if (y->IsString()) {
         return Just(
             String::Equals(Handle<String>::cast(x), Handle<String>::cast(y)));
       } else if (y->IsNumber()) {
         x = String::ToNumber(Handle<String>::cast(x));
         return Just(NumberEquals(x, y));
       } else if (y->IsBoolean()) {
         x = String::ToNumber(Handle<String>::cast(x));
         return Just(NumberEquals(*x, Handle<Oddball>::cast(y)->to_number()));
       } else if (y->IsJSReceiver() && !y->IsUndetectableObject()) {
-        if (JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y)).ToHandle(&y)) {
-          continue;
-        } else {
+        if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y))
+                 .ToHandle(&y)) {
           return Nothing<bool>();
         }
       } else {
         return Just(false);
       }
     } else if (x->IsBoolean()) {
       if (y->IsOddball()) {
         return Just(x.is_identical_to(y));
       } else if (y->IsNumber()) {
         return Just(NumberEquals(Handle<Oddball>::cast(x)->to_number(), *y));
       } else if (y->IsString()) {
         y = String::ToNumber(Handle<String>::cast(y));
         return Just(NumberEquals(Handle<Oddball>::cast(x)->to_number(), *y));
       } else if (y->IsJSReceiver() && !y->IsUndetectableObject()) {
         if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y))
                  .ToHandle(&y)) {
           return Nothing<bool>();
         }
         x = Oddball::ToNumber(Handle<Oddball>::cast(x));
-        continue;
       } else {
         return Just(false);
       }
     } else if (x->IsSymbol()) {
       if (y->IsSymbol()) {
         return Just(x.is_identical_to(y));
       } else if (y->IsJSReceiver() && !y->IsUndetectableObject()) {
-        if (JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y)).ToHandle(&y)) {
-          continue;
-        } else {
+        if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y))
+                 .ToHandle(&y)) {
           return Nothing<bool>();
         }
       } else {
         return Just(false);
       }
     } else if (x->IsSimd128Value()) {
       if (y->IsSimd128Value()) {
         return Just(Simd128Value::Equals(Handle<Simd128Value>::cast(x),
                                          Handle<Simd128Value>::cast(y)));
       } else if (y->IsJSReceiver() && !y->IsUndetectableObject()) {
-        if (JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y)).ToHandle(&y)) {
-          continue;
-        } else {
+        if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(y))
+                 .ToHandle(&y)) {
           return Nothing<bool>();
         }
       } else {
         return Just(false);
       }
     } else if (x->IsJSReceiver() && !x->IsUndetectableObject()) {
       if (y->IsJSReceiver()) {
         return Just(x.is_identical_to(y));
       } else if (y->IsNull() || y->IsUndefined()) {
         return Just(false);
       } else if (y->IsBoolean()) {
         y = Oddball::ToNumber(Handle<Oddball>::cast(y));
-        continue;
-      } else if (JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(x))
-                     .ToHandle(&x)) {
-        continue;
-      } else {
+      } else if (!JSReceiver::ToPrimitive(Handle<JSReceiver>::cast(x))
+                      .ToHandle(&x)) {
         return Nothing<bool>();
       }
     } else {
       return Just(
           (x->IsNull() || x->IsUndefined() || x->IsUndetectableObject()) &&
           (y->IsNull() || y->IsUndefined() || y->IsUndetectableObject()));
     }
-    UNREACHABLE();
   }
 }
 
 
 bool Object::StrictEquals(Object* that) {
   if (this->IsNumber()) {
     if (!that->IsNumber()) return false;
     return NumberEquals(this, that);
   } else if (this->IsString()) {
     if (!that->IsString()) return false;
@@ skipping 17546 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8