Improved function entry hook coverage

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 014d82ee4f0aab86c5f16ca339c22b335c42753b..edffca18f42c7e792da0857f512172b27238a315 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -300,8 +300,13 @@ static inline bool EmptyCheck(const char* location, const v8::Data* obj) {
 // --- S t a t i c s ---
 
 
-static bool InitializeHelper() {
-  if (i::Snapshot::Initialize()) return true;
+static bool InitializeHelper(i::Isolate* isolate) {
+  // If the isolate has a function entry hook, it needs to re-build all its
+  // code stubs with entry hooks embedded, so let's deserialize a snapshot.
+  if (isolate == NULL || isolate->function_entry_hook() == NULL) {
+    if (i::Snapshot::Initialize())
+      return true;
+  }
   return i::V8::Initialize(NULL);
 }
 
@@ -313,7 +318,7 @@ static inline bool EnsureInitializedForIsolate(i::Isolate* isolate,
     if (isolate->IsInitialized()) return true;
   }
   ASSERT(isolate == i::Isolate::Current());
-  return ApiCheck(InitializeHelper(), location, "Error initializing V8");
+  return ApiCheck(InitializeHelper(isolate), location, "Error initializing V8");
 }
 
 // Some initializing API functions are called early and may be
@@ -5211,7 +5216,7 @@ bool v8::V8::Initialize() {
   if (isolate != NULL && isolate->IsInitialized()) {
     return true;
   }
-  return InitializeHelper();
+  return InitializeHelper(isolate);
 }
 
 
@@ -5227,7 +5232,30 @@ void v8::V8::SetReturnAddressLocationResolver(
 
 
 bool v8::V8::SetFunctionEntryHook(FunctionEntryHook entry_hook) {
-  return i::ProfileEntryHookStub::SetFunctionEntryHook(entry_hook);
+  return SetFunctionEntryHook(Isolate::GetCurrent(), entry_hook);
+}
+
+
+bool v8::V8::SetFunctionEntryHook(Isolate* ext_isolate,
+                                  FunctionEntryHook entry_hook) {
+  ASSERT(ext_isolate != NULL);
+  ASSERT(entry_hook != NULL);
+
+  i::Isolate* isolate = reinterpret_cast<i::Isolate*>(ext_isolate);
+
+  // The entry hook can only be set before the Isolate is initialized, as
+  // otherwise the Isolate's code stubs generated at initialization won't
+  // contain entry hooks.
+  if (isolate->IsInitialized())
+    return false;
+
+  // Setting an entry hook is a one-way operation, once set, it cannot be
+  // changed or unset.
+  if (isolate->function_entry_hook() != NULL)
+    return false;
+
+  isolate->set_function_entry_hook(entry_hook);
+  return true;
 }