[VM, Precompiler] PoC Obfuscator

runtime/vm/precompiler.h

Index: runtime/vm/precompiler.h
diff --git a/runtime/vm/precompiler.h b/runtime/vm/precompiler.h
index 2aff2a4d0cac1f6ef279bce0da3f815b4a4eb876..2fac04f85cd53f049fba32a9a2185784a18b436a 100644
--- a/runtime/vm/precompiler.h
+++ b/runtime/vm/precompiler.h
@@ -398,6 +398,8 @@ class Precompiler : public ValueObject {
   void SwitchICCalls();
   void ResetPrecompilerState();
 
+  void Obfuscate();
+
   void CollectDynamicFunctionNames();
 
   void PrecompileStaticInitializers();
@@ -476,6 +478,126 @@ class FunctionsTraits {
 
 typedef UnorderedHashSet<FunctionsTraits> UniqueFunctionsSet;
 
+#if defined(DART_PRECOMPILER)
+// ObfuscationMap maps Strings to Strings.
+class ObfuscationMapTraits {
+ public:
+  static const char* Name() { return "ObfuscationMapTraits"; }
+  static bool ReportStats() { return false; }
+
+  // Only for non-descriptor lookup and table expansion.
+  static bool IsMatch(const Object& a, const Object& b) {
+    return a.raw() == b.raw();
+  }
+
+  static uword Hash(const Object& key) { return String::Cast(key).Hash(); }
+};
+typedef UnorderedHashMap<ObfuscationMapTraits> ObfuscationMap;
+
+class Obfuscator {
+ public:
+  Obfuscator(Thread* thread, const String& private_key);
+  ~Obfuscator();
+
+  RawString* Rename(const String& name, bool atomic = false) {
+    if (state_ == NULL) {
+      return name.raw();
+    }
+
+    return state_->RenameImpl(name, atomic);
+  }
+
+  static void ObfuscateSymbolInstance(Thread* thread, const Instance& instance);
+
+  static void Deobfuscate(Thread* thread, const GrowableObjectArray& pieces);
+
+ private:
+  void InitializeRenamingMap(Isolate* isolate);
+  void PreventRenaming(Dart_QualifiedFunctionName* entry_points);
+  void PreventRenaming(const char* name);
+  void PreventRenaming(const String& name) { state_->PreventRenaming(name); }
+
+  static const intptr_t kSavedStateNameIndex = 0;
+  static const intptr_t kSavedStateRenamesIndex = 1;
+  static const intptr_t kSavedStateSize = 2;
+
+  static RawArray* GetRenamesFromSavedState(const Array& saved_state) {
+    Array& renames = Array::Handle();
+    renames ^= saved_state.At(kSavedStateRenamesIndex);
+    return renames.raw();
+  }
+
+  static RawString* GetNameFromSavedState(const Array& saved_state) {
+    String& name = String::Handle();
+    name ^= saved_state.At(kSavedStateNameIndex);
+    return name.raw();
+  }
+
+  class ObfuscationState : public ZoneAllocated {
+   public:
+    ObfuscationState(Thread* thread,
+                     const Array& saved_state,
+                     const String& private_key)
+        : thread_(thread),
+          saved_state_(saved_state),
+          renames_(GetRenamesFromSavedState(saved_state)),
+          private_key_(private_key),
+          string_(String::Handle(thread->zone())),
+          renamed_(String::Handle(thread->zone())) {
+      memset(name_, 0, sizeof(name_));
+
+      string_ = GetNameFromSavedState(saved_state);
+      if (!string_.IsNull()) {
+        string_.ToUTF8(reinterpret_cast<uint8_t*>(name_), sizeof(name_));
+      }
+    }
+
+    void SaveState();
+
+    RawString* RenameImpl(const String& name, bool atomic);
+    RawString* BuildRename(const String& name, bool atomic);
+    RawString* NewAtomicRename(bool should_be_private);
+
+    void NextName();
+
+    void PreventRenaming(const String& name);
+    void PreventRenaming(const char* name);
+
+   private:
+    Thread* thread_;
+
+    const Array& saved_state_;
+
+    char name_[100];
+    ObfuscationMap renames_;
+
+    const String& private_key_;
+
+    String& string_;
+    String& renamed_;
+  };
+
+  ObfuscationState* state_;
+};
+#else
+// Minimal do-nothing implementation of an Obfuscator for non-precompiler
+// builds.
+class Obfuscator {
+ public:
+  Obfuscator(Thread* thread, const String& private_key) {}
+  ~Obfuscator() {}
+
+  RawString* Rename(const String& name, bool atomic = false) {
+    return name.raw();
+  }
+
+  static void ObfuscateSymbolInstance(Thread* thread,
+                                      const Instance& instance) {}
+
+  static void Deobfuscate(Thread* thread, const GrowableObjectArray& pieces) {}
+};
+#endif  // DART_PRECOMPILER
+
 }  // namespace dart
 
 #endif  // RUNTIME_VM_PRECOMPILER_H_