Generalize utilities to allow code templatization

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/17853004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15357 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.cc

@@ -10109,31 +10109,47 @@ SafepointEntry Code::GetSafepointEntry(Address pc) {
 }
 
 
-Map* Code::FindFirstMap() {
+Object* Code::FindNthObject(int n, Map* match_map) {
   ASSERT(is_inline_cache_stub());
   DisallowHeapAllocation no_allocation;
   int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
   for (RelocIterator it(this, mask); !it.done(); it.next()) {
     RelocInfo* info = it.rinfo();
     Object* object = info->target_object();
-    if (object->IsMap()) return Map::cast(object);
+    if (object->IsHeapObject()) {
+      if (HeapObject::cast(object)->map() == match_map) {
+        if (--n == 0) return object;
+      }
+    }
   }
   return NULL;
 }
 
 
-void Code::ReplaceFirstMap(Map* replace_with) {
+Map* Code::FindFirstMap() {
+  Object* result = FindNthObject(1, GetHeap()->meta_map());
+  return (result != NULL) ? Map::cast(result) : NULL;
+}
+
+
+void Code::ReplaceNthObject(int n,
+                            Map* match_map,
+                            Object* replace_with) {
   ASSERT(is_inline_cache_stub());
   DisallowHeapAllocation no_allocation;
   int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
   for (RelocIterator it(this, mask); !it.done(); it.next()) {
     RelocInfo* info = it.rinfo();
     Object* object = info->target_object();
-    if (object->IsMap()) {
+    if (object->IsHeapObject()) {
+      if (HeapObject::cast(object)->map() == match_map) {
+        if (--n == 0) {
           info->set_target_object(replace_with);
           return;
         }
       }
+    }
+  }
   UNREACHABLE();
 }
 
@@ -10150,6 +10166,11 @@ void Code::FindAllMaps(MapHandleList* maps) {
 }
 
 
+void Code::ReplaceFirstMap(Map* replace_with) {
+  ReplaceNthObject(1, GetHeap()->meta_map(), replace_with);
+}
+
+
 Code* Code::FindFirstCode() {
   ASSERT(is_inline_cache_stub());
   DisallowHeapAllocation no_allocation;
@@ -10191,6 +10212,21 @@ Name* Code::FindFirstName() {
 }
 
 
+void Code::ReplaceNthCell(int n, Cell* replace_with) {
+  ASSERT(is_inline_cache_stub());
+  DisallowHeapAllocation no_allocation;
+  int mask = RelocInfo::ModeMask(RelocInfo::CELL);
+  for (RelocIterator it(this, mask); !it.done(); it.next()) {
+    RelocInfo* info = it.rinfo();
+    if (--n == 0) {
+      info->set_target_cell(replace_with);
+      return;
+    }
+  }
+  UNREACHABLE();
+}
+
+
 void Code::ClearInlineCaches() {
   int mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET) |
              RelocInfo::ModeMask(RelocInfo::CONSTRUCT_CALL) |

src/objects.h

@@ -4685,6 +4685,10 @@ class Code: public HeapObject {
   // Get the safepoint entry for the given pc.
   SafepointEntry GetSafepointEntry(Address pc);
 
+  // Find an object in a stub with a specified map
+  Object* FindNthObject(int n, Map* match_map);
+  void ReplaceNthObject(int n, Map* match_map, Object* replace_with);
+
   // Find the first map in an IC stub.
   Map* FindFirstMap();
   void FindAllMaps(MapHandleList* maps);
@@ -4697,6 +4701,8 @@ class Code: public HeapObject {
   // Find the first name in an IC stub.
   Name* FindFirstName();
 
+  void ReplaceNthCell(int n, Cell* replace_with);
+
   class ExtraICStateStrictMode: public BitField<StrictModeFlag, 0, 1> {};
   class ExtraICStateKeyedAccessStoreMode:
       public BitField<KeyedAccessStoreMode, 1, 4> {};  // NOLINT