Create C++ static initializer for use in global objects. (#115)

runtime/src/launcher/cpp/launcher.cpp

@@ -9,7 +9,8 @@ ArrayHeader* setupArgs(int argc, char** argv) {
     ArrayHeader* args = AllocArrayInstance(theArrayTypeInfo, SCOPE_GLOBAL, argc-1);
 
     for (int i = 0; i < argc-1; i++) {
-        Kotlin_Array_set(args, i, AllocStringInstance( argv[i+1], strlen(argv[i+1]) ));
+      Kotlin_Array_set(args, i, AllocStringInstance(
+          SCOPE_GLOBAL, argv[i+1], strlen(argv[i+1]) ));
     }
 
     return args;
@@ -27,4 +28,3 @@ int main(int argc, char** argv) {
     // Yes, we have to follow Java convention and return zero.
     return 0;
 }
-

runtime/src/main/cpp/Exceptions.cpp

@@ -36,7 +36,7 @@ class AutoFree {
 
 // TODO: this method ignores the encoding
 KString CreateKotlinStringFromCString(const char* str) {
-  return AllocStringInstance(str, strlen(str));
+  return AllocStringInstance(SCOPE_GLOBAL, str, strlen(str));
 }
 
 #ifdef __cplusplus

runtime/src/main/cpp/Memory.cpp

@@ -89,7 +89,8 @@ ArrayHeader* AllocArrayInstance(
   return ArrayContainer(type_info, elements).GetPlace();
 }
 
-ArrayHeader* AllocStringInstance(const char* data, uint32_t length) {
+ArrayHeader* AllocStringInstance(
+    PlacementHint hint, const char* data, uint32_t length) {
   ArrayHeader* result = ArrayContainer(theStringTypeInfo, length).GetPlace();
   memcpy(
       ByteArrayAddressOfElementAt(result, 0),
@@ -97,6 +98,35 @@ ArrayHeader* AllocStringInstance(const char* data, uint32_t length) {
       length);
   return result;
 }
+
+ObjHeader* InitInstance(
+    ObjHeader** location, const TypeInfo* type_info, PlacementHint hint,
+    void (*ctor)(ObjHeader*)) {
+  ObjHeader* sentinel = reinterpret_cast<ObjHeader*>(1);
+  ObjHeader* value;
+  // Wait until other initializers.
+  while ((value = __sync_val_compare_and_swap(
+             location, nullptr, sentinel)) == sentinel) {
+    // TODO: consider yielding.
+  }
+
+  if (value != nullptr) {
+    // OK'ish, inited by someone else.
+    return value;
+  }
+
+  ObjHeader* instance = AllocInstance(type_info, hint);
+  try {
+    ctor(instance);
+    __sync_val_compare_and_swap(location, sentinel, instance);
+    return instance;
+  } catch (...) {
+    Release(instance->container());
+    __sync_val_compare_and_swap(location, sentinel, nullptr);
+    return nullptr;
+  }
+}
+
 #ifdef __cplusplus
 }
 #endif

runtime/src/main/cpp/Memory.h

@@ -254,7 +254,11 @@ void InitMemory();
 ObjHeader* AllocInstance(const TypeInfo* type_info, PlacementHint hint);
 ArrayHeader* AllocArrayInstance(
     const TypeInfo* type_info, PlacementHint hint, uint32_t elements);
-ArrayHeader* AllocStringInstance(const char* data, uint32_t length);
+ArrayHeader* AllocStringInstance(PlacementHint hint,
+                                 const char* data, uint32_t length);
+ObjHeader* InitInstance(
+    ObjHeader** location, const TypeInfo* type_info, PlacementHint hint,
+    void (*ctor)(ObjHeader*));
 
 #ifdef __cplusplus
 }