Remove unnecessary explicity prototype check.

The prototype is implicitly checked through a map check of the holder.
This is either checked in CheckPrototypes, or as part of the IC.

Review URL: https://chromiumcodereview.appspot.com/13529017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14155 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/stub-cache-arm.cc

@@ -1225,7 +1225,7 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     Handle<GlobalObject> global) {
   Label miss;
 
-  Register reg = HandlerFrontendHeader(object, receiver(), last, name, &miss);
+  HandlerFrontendHeader(object, receiver(), last, name, &miss);
 
   // If the last object in the prototype chain is a global object,
   // check that the global property cell is empty.
@@ -1233,13 +1233,6 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     GenerateCheckPropertyCell(masm(), global, name, scratch2(), &miss);
   }
 
-  if (!last->HasFastProperties()) {
-    __ ldr(scratch2(), FieldMemOperand(reg, HeapObject::kMapOffset));
-    __ ldr(scratch2(), FieldMemOperand(scratch2(), Map::kPrototypeOffset));
-    __ cmp(scratch2(), Operand(isolate()->factory()->null_value()));
-    __ b(ne, &miss);
-  }
-
   HandlerFrontendFooter(success, &miss);
 }
 

src/ia32/stub-cache-ia32.cc

@@ -1113,7 +1113,7 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     Handle<GlobalObject> global) {
   Label miss;
 
-  Register reg = HandlerFrontendHeader(object, receiver(), last, name, &miss);
+  HandlerFrontendHeader(object, receiver(), last, name, &miss);
 
   // If the last object in the prototype chain is a global object,
   // check that the global property cell is empty.
@@ -1121,13 +1121,6 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     GenerateCheckPropertyCell(masm(), global, name, scratch2(), &miss);
   }
 
-  if (!last->HasFastProperties()) {
-    __ mov(scratch2(), FieldOperand(reg, HeapObject::kMapOffset));
-    __ mov(scratch2(), FieldOperand(scratch2(), Map::kPrototypeOffset));
-    __ cmp(scratch2(), isolate()->factory()->null_value());
-    __ j(not_equal, &miss);
-  }
-
   HandlerFrontendFooter(success, &miss);
 }
 

src/mips/stub-cache-mips.cc

@@ -1229,7 +1229,7 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     Handle<GlobalObject> global) {
   Label miss;
 
-  Register reg = HandlerFrontendHeader(object, receiver(), last, name, &miss);
+  HandlerFrontendHeader(object, receiver(), last, name, &miss);
 
   // If the last object in the prototype chain is a global object,
   // check that the global property cell is empty.
@@ -1237,13 +1237,6 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     GenerateCheckPropertyCell(masm(), global, name, scratch2(), &miss);
   }
 
-  if (!last->HasFastProperties()) {
-    __ lw(scratch2(), FieldMemOperand(reg, HeapObject::kMapOffset));
-    __ lw(scratch2(), FieldMemOperand(scratch2(), Map::kPrototypeOffset));
-    __ Branch(&miss, ne, scratch2(),
-        Operand(isolate()->factory()->null_value()));
-  }
-
   HandlerFrontendFooter(success, &miss);
 }
 

src/x64/stub-cache-x64.cc

@@ -1077,7 +1077,7 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     Handle<GlobalObject> global) {
   Label miss;
 
-  Register reg = HandlerFrontendHeader(object, receiver(), last, name, &miss);
+  HandlerFrontendHeader(object, receiver(), last, name, &miss);
 
   // If the last object in the prototype chain is a global object,
   // check that the global property cell is empty.
@@ -1085,13 +1085,6 @@ void BaseLoadStubCompiler::NonexistentHandlerFrontend(
     GenerateCheckPropertyCell(masm(), global, name, scratch2(), &miss);
   }
 
-  if (!last->HasFastProperties()) {
-    __ movq(scratch2(), FieldOperand(reg, HeapObject::kMapOffset));
-    __ movq(scratch2(), FieldOperand(scratch2(), Map::kPrototypeOffset));
-    __ Cmp(scratch2(), isolate()->factory()->null_value());
-    __ j(not_equal, &miss);
-  }
-
   HandlerFrontendFooter(success, &miss);
 }