Do not embed function in DirectLoadGlobalFunctionPrototype.

src/ic/arm64/handler-compiler-arm64.cc

Index: src/ic/arm64/handler-compiler-arm64.cc
diff --git a/src/ic/arm64/handler-compiler-arm64.cc b/src/ic/arm64/handler-compiler-arm64.cc
index 8571faec714fa05b8a250b4d88310d21aa15cb6b..64f615841698718d651d3f842a66293246623426 100644
--- a/src/ic/arm64/handler-compiler-arm64.cc
+++ b/src/ic/arm64/handler-compiler-arm64.cc
@@ -57,24 +57,27 @@ void PropertyHandlerCompiler::GenerateDictionaryNegativeLookup(
 
 
 void NamedLoadHandlerCompiler::GenerateDirectLoadGlobalFunctionPrototype(
-    MacroAssembler* masm, int index, Register prototype, Label* miss) {
+    MacroAssembler* masm, int index, Register prototype, Register scratch,
+    Label* miss) {
   Isolate* isolate = masm->isolate();
   // Get the global function with the given index.
-  Handle<JSFunction> function(
+  Handle<JSFunction> jsfunction(
       JSFunction::cast(isolate->native_context()->get(index)));
+  Handle<WeakCell> cell = isolate->factory()->NewWeakCell(jsfunction);
 
   // Check we're still in the same context.
-  Register scratch = prototype;
+  Register function = prototype;
   __ Ldr(scratch, GlobalObjectMemOperand());
   __ Ldr(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
-  __ Ldr(scratch, ContextMemOperand(scratch, index));
-  __ Cmp(scratch, Operand(function));
+  __ Ldr(function, ContextMemOperand(scratch, index));
+  __ CmpWeakValue(function, cell, scratch);

[Toon Verwaest, 2014/12/03 16:22:09]

Why still embed the weak cell if all you do is miss if it's different? We'll do
a map-check on the prototype itself anyway later on if we use it, so checking
the function itself is not necessary as far as I can tell.

   __ B(ne, miss);
 
   // Load its initial map. The global functions all have initial maps.
-  __ Mov(prototype, Operand(Handle<Map>(function->initial_map())));
+  __ Ldr(scratch,
+         FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
   // Load the prototype from the initial map.
-  __ Ldr(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
+  __ Ldr(prototype, FieldMemOperand(scratch, Map::kPrototypeOffset));
 }