Bug 1288457 - Part 8: Use constexpr instead of #defines in js/Class. r=mgaudet

Differential Revision: https://phabricator.services.mozilla.com/D42877

--HG--
extra : moz-landing-system : lando

js/public/Class.h

@@ -642,9 +642,6 @@ struct MOZ_STATIC_CLASS ClassExtension {
   JSObjectMovedOp objectMovedOp;
 };
 
-#define JS_NULL_CLASS_SPEC nullptr
-#define JS_NULL_CLASS_EXT nullptr
-
 struct MOZ_STATIC_CLASS ObjectOps {
   LookupPropertyOp lookupProperty;
   DefinePropertyOp defineProperty;
@@ -657,10 +654,13 @@ struct MOZ_STATIC_CLASS ObjectOps {
   JSFunToStringOp funToString;
 };
 
-#define JS_NULL_OBJECT_OPS nullptr
-
 }  // namespace js
 
+static constexpr const js::ClassSpec* JS_NULL_CLASS_SPEC = nullptr;
+static constexpr const js::ClassExtension* JS_NULL_CLASS_EXT = nullptr;
+
+static constexpr const js::ObjectOps* JS_NULL_OBJECT_OPS = nullptr;
+
 // Classes, objects, and properties.
 
 // Objects have private slot.
@@ -703,14 +703,12 @@ static const uint32_t JSCLASS_RESERVED_SLOTS_WIDTH = 8;
 static const uint32_t JSCLASS_RESERVED_SLOTS_MASK =
     JS_BITMASK(JSCLASS_RESERVED_SLOTS_WIDTH);
 
-#define JSCLASS_HAS_RESERVED_SLOTS(n) \
-  (((n)&JSCLASS_RESERVED_SLOTS_MASK) << JSCLASS_RESERVED_SLOTS_SHIFT)
-#define JSCLASS_RESERVED_SLOTS(clasp)                 \
-  (((clasp)->flags >> JSCLASS_RESERVED_SLOTS_SHIFT) & \
-   JSCLASS_RESERVED_SLOTS_MASK)
+static constexpr uint32_t JSCLASS_HAS_RESERVED_SLOTS(uint32_t n) {
+  return (n & JSCLASS_RESERVED_SLOTS_MASK) << JSCLASS_RESERVED_SLOTS_SHIFT;
+}
 
-#define JSCLASS_HIGH_FLAGS_SHIFT \
-  (JSCLASS_RESERVED_SLOTS_SHIFT + JSCLASS_RESERVED_SLOTS_WIDTH)
+static constexpr uint32_t JSCLASS_HIGH_FLAGS_SHIFT =
+    JSCLASS_RESERVED_SLOTS_SHIFT + JSCLASS_RESERVED_SLOTS_WIDTH;
 
 static const uint32_t JSCLASS_INTERNAL_FLAG1 =
     1 << (JSCLASS_HIGH_FLAGS_SHIFT + 0);
@@ -752,13 +750,13 @@ static const uint32_t JSCLASS_GLOBAL_APPLICATION_SLOTS = 5;
 static const uint32_t JSCLASS_GLOBAL_SLOT_COUNT =
     JSCLASS_GLOBAL_APPLICATION_SLOTS + JSProto_LIMIT * 2 + 32;
 
-#define JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(n) \
-  (JSCLASS_IS_GLOBAL |                     \
-   JSCLASS_HAS_RESERVED_SLOTS(JSCLASS_GLOBAL_SLOT_COUNT + (n)))
-#define JSCLASS_GLOBAL_FLAGS JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(0)
-#define JSCLASS_HAS_GLOBAL_FLAG_AND_SLOTS(clasp) \
-  (((clasp)->flags & JSCLASS_IS_GLOBAL) &&       \
-   JSCLASS_RESERVED_SLOTS(clasp) >= JSCLASS_GLOBAL_SLOT_COUNT)
+static constexpr uint32_t JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(uint32_t n) {
+  return JSCLASS_IS_GLOBAL |
+         JSCLASS_HAS_RESERVED_SLOTS(JSCLASS_GLOBAL_SLOT_COUNT + n);
+}
+
+static constexpr uint32_t JSCLASS_GLOBAL_FLAGS =
+    JSCLASS_GLOBAL_FLAGS_WITH_SLOTS(0);
 
 // Fast access to the original value of each standard class's prototype.
 static const uint32_t JSCLASS_CACHED_PROTO_SHIFT =
@@ -766,11 +764,9 @@ static const uint32_t JSCLASS_CACHED_PROTO_SHIFT =
 static const uint32_t JSCLASS_CACHED_PROTO_MASK =
     JS_BITMASK(js::JSCLASS_CACHED_PROTO_WIDTH);
 
-#define JSCLASS_HAS_CACHED_PROTO(key) \
-  (uint32_t(key) << JSCLASS_CACHED_PROTO_SHIFT)
-#define JSCLASS_CACHED_PROTO_KEY(clasp)                          \
-  ((JSProtoKey)(((clasp)->flags >> JSCLASS_CACHED_PROTO_SHIFT) & \
-                JSCLASS_CACHED_PROTO_MASK))
+static constexpr uint32_t JSCLASS_HAS_CACHED_PROTO(JSProtoKey key) {
+  return uint32_t(key) << JSCLASS_CACHED_PROTO_SHIFT;
+}
 
 struct MOZ_STATIC_CLASS JSClassOps {
   /* Function pointer members (may be null). */
@@ -787,7 +783,7 @@ struct MOZ_STATIC_CLASS JSClassOps {
   JSTraceOp trace;
 };
 
-#define JS_NULL_CLASS_OPS nullptr
+static constexpr const JSClassOps* JS_NULL_CLASS_OPS = nullptr;
 
 struct JSClass {
   const char* name;
@@ -939,6 +935,21 @@ struct JSClass {
   }
 };
 
+static constexpr uint32_t JSCLASS_RESERVED_SLOTS(const JSClass* clasp) {
+  return (clasp->flags >> JSCLASS_RESERVED_SLOTS_SHIFT) &
+         JSCLASS_RESERVED_SLOTS_MASK;
+}
+
+static constexpr bool JSCLASS_HAS_GLOBAL_FLAG_AND_SLOTS(const JSClass* clasp) {
+  return (clasp->flags & JSCLASS_IS_GLOBAL) &&
+         JSCLASS_RESERVED_SLOTS(clasp) >= JSCLASS_GLOBAL_SLOT_COUNT;
+}
+
+static constexpr JSProtoKey JSCLASS_CACHED_PROTO_KEY(const JSClass* clasp) {
+  return JSProtoKey((clasp->flags >> JSCLASS_CACHED_PROTO_SHIFT) &
+                    JSCLASS_CACHED_PROTO_MASK);
+}
+
 namespace js {
 
 /**