Compile cpp code with -Wall (#4310)

-Wunused-function is temporarily disabled because it conflicts with interesting but unused functions. When we will have C++ tests on runtime, these interesting functions will get tested and so stop being unused.

build-tools/src/main/kotlin/org/jetbrains/kotlin/CompileToBitcode.kt

@@ -67,6 +67,8 @@ open class CompileToBitcode @Inject constructor(@InputDirectory val srcRoot: Fil
                             "-Werror", "-ftls-model=initial-exec", "-Wno-unused-function")
                 Language.CPP ->
                     listOfNotNull("-std=c++14", "-Werror", "-O2",
+                            "-Wall",
+                            "-Wno-unused-function",  // TODO: Enable this warning when we have C++ runtime tests.
                             "-fPIC".takeIf { !HostManager().targetByName(target).isMINGW })
             }
             return commonFlags + languageFlags + compilerArgs

common/src/hash/cpp/Base64.cpp

@@ -136,7 +136,11 @@ int DecodeBase64(
   size_t buf = 0, len = 0;
 
   while (in < end) {
-    unsigned char c = kDecode[*in++];
+    // char may be a signed type. Explicitly convert it to an unsigned byte,
+    // so that indexing into kDecode array is safe. The latter has exactly
+    // 256 elements, so any unsigned byte value is valid.
+    uint8_t index = *in++;
+    unsigned char c = kDecode[index];
 
     switch (c) {
       case WHITESPACE: continue;   /* skip whitespace */

common/src/hash/cpp/City.cpp

@@ -26,10 +26,6 @@ static const uint64_t k0 = 0xc3a5c85c97cb3127ULL;
 static const uint64_t k1 = 0xb492b66fbe98f273ULL;
 static const uint64_t k2 = 0x9ae16a3b2f90404fULL;
 
-// Magic numbers for 32-bit hashing.  Copied from Murmur3.
-static const uint32_t c1 = 0xcc9e2d51;
-static const uint32_t c2 = 0x1b873593;
-
 uint64_t UNALIGNED_LOAD64(const char *p) {
   uint64_t result;
   memcpy(&result, p, sizeof(result));

common/src/hash/cpp/Names.cpp

@@ -29,7 +29,6 @@ constexpr uint32_t PrintableHexSize(uint32_t input_length) {
 
 void PrintableHex(const uint8_t* data, uint32_t data_length, char* hex) {
   static const char* hex_digits = "0123456789ABCDEF";
-  int i = 0;
   for(int i = 0; i < data_length; ++i) {
     *hex++ = hex_digits[(*data >> 4) & 0xf];
     *hex++ = hex_digits[(*data++) & 0xf];

runtime/src/main/cpp/KString.cpp

@@ -44,7 +44,7 @@ OBJ_GETTER(utf8ToUtf16Impl, const char* rawString, const char* end, uint32_t cha
   if (rawString == nullptr) RETURN_OBJ(nullptr);
   ArrayHeader* result = AllocArrayInstance(theStringTypeInfo, charCount, OBJ_RESULT)->array();
   KChar* rawResult = CharArrayAddressOfElementAt(result, 0);
-  auto convertResult = conversion(rawString, end, rawResult);
+  conversion(rawString, end, rawResult);
   RETURN_OBJ(result->obj());
 }
 
@@ -1091,7 +1091,6 @@ KInt Kotlin_String_lastIndexOfChar(KString thiz, KChar ch, KInt fromIndex) {
   if (fromIndex >= thiz->count_) {
     fromIndex = thiz->count_ - 1;
   }
-  KInt count = thiz->count_;
   KInt index = fromIndex;
   const KChar* thizRaw = CharArrayAddressOfElementAt(thiz, index);
   while (index >= 0) {
@@ -1116,7 +1115,6 @@ KInt Kotlin_String_indexOfString(KString thiz, KString other, KInt fromIndex) {
   if (other->count_ == 0) {
     return fromIndex;
   }
-  KInt count = thiz->count_;
   const KChar* thizRaw = CharArrayAddressOfElementAt(thiz, fromIndex);
   const KChar* otherRaw = CharArrayAddressOfElementAt(other, 0);
   void* result = konan::memmem(thizRaw, (thiz->count_ - fromIndex) * sizeof(KChar),

runtime/src/main/cpp/Memory.cpp

@@ -119,13 +119,18 @@ typedef KStdUnorderedMap<void**, std::pair<KRef*,int>> KThreadLocalStorageMap;
 // Prevents clang from replacing FrameOverlay struct
 // with single pointer.
 // Can be removed when FrameOverlay will become more complex.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-variable"
 FrameOverlay exportFrameOverlay;
+#pragma clang diagnostic pop
 
 // Current number of allocated containers.
 volatile int allocCount = 0;
 volatile int aliveMemoryStatesCount = 0;
 
+#if USE_CYCLIC_GC
 KBoolean g_hasCyclicCollector = true;
+#endif  // USE_CYCLIC_GC
 
 // TODO: can we pass this variable as an explicit argument?
 THREAD_LOCAL_VARIABLE MemoryState* memoryState = nullptr;
@@ -980,7 +985,7 @@ void freeContainer(ContainerHeader* container) {
   runDeallocationHooks(container);
 
   // Now let's clean all object's fields in this container.
-  traverseContainerObjectFields(container, [container](ObjHeader** location) {
+  traverseContainerObjectFields(container, [](ObjHeader** location) {
       ZeroHeapRef(location);
   });
 
@@ -1017,7 +1022,7 @@ void depthFirstTraversal(ContainerHeader* start, bool* hasCycles,
       continue;
     }
     toVisit.push_front(markAsRemoved(container));
-    traverseContainerReferredObjects(container, [container, hasCycles, firstBlocker, &order, &toVisit](ObjHeader* obj) {
+    traverseContainerReferredObjects(container, [container, hasCycles, firstBlocker, &toVisit](ObjHeader* obj) {
       if (*firstBlocker != nullptr)
         return;
       if (obj->has_meta_object() && ((obj->meta_object()->flags_ & MF_NEVER_FROZEN) != 0)) {
@@ -1426,7 +1431,7 @@ void collectWhite(MemoryState* state, ContainerHeader* start) {
      toVisit.pop_front();
      if (container->color() != CONTAINER_TAG_GC_WHITE || container->buffered()) continue;
      container->setColorAssertIfGreen(CONTAINER_TAG_GC_BLACK);
-     traverseContainerObjectFields(container, [state, &toVisit](ObjHeader** location) {
+     traverseContainerObjectFields(container, [&toVisit](ObjHeader** location) {
         auto* ref = *location;
         if (ref == nullptr) return;
         auto* childContainer = ref->container();
@@ -1610,7 +1615,9 @@ void decrementStack(MemoryState* state) {
 void garbageCollect(MemoryState* state, bool force) {
   RuntimeAssert(!state->gcInProgress, "Recursive GC is disallowed");
 
+#if TRACE_GC
   uint64_t allocSinceLastGc = state->allocSinceLastGc;
+#endif  // TRACE_GC
   state->allocSinceLastGc = 0;
 
   if (!IsStrictMemoryModel) {
@@ -2493,7 +2500,7 @@ void freezeAcyclic(ContainerHeader* rootContainer, ContainerHeaderSet* newlyFroz
       newlyFrozen->insert(current);
     MEMORY_LOG("freezing %p\n", current)
     current->freeze();
-    traverseContainerReferredObjects(current, [current, &queue](ObjHeader* obj) {
+    traverseContainerReferredObjects(current, [&queue](ObjHeader* obj) {
         ContainerHeader* objContainer = obj->container();
         if (canFreeze(objContainer)) {
           if (objContainer->marked())

runtime/src/main/cpp/ObjCExport.mm

@@ -799,8 +799,6 @@ static void throwIfCantBeOverridden(Class clazz, const KotlinToObjCMethodAdapter
 }
 
 static const TypeInfo* createTypeInfo(Class clazz, const TypeInfo* superType, const TypeInfo* fieldsInfo) {
-  Class superClass = class_getSuperclass(clazz);
-
   KStdUnorderedSet<SEL> definedSelectors;
   addDefinedSelectors(clazz, definedSelectors);
 
@@ -913,7 +911,7 @@ static const TypeInfo* createTypeInfo(Class clazz, const TypeInfo* superType, co
       auto interfaceVTablesIt = interfaceVTables.find(interfaceId);
       if (interfaceVTablesIt == interfaceVTables.end()) {
         itableEqualsSuper = false;
-        interfaceVTables.emplace(interfaceId, std::move(KStdVector<VTableElement>(interfaceVTableSize)));
+        interfaceVTables.emplace(interfaceId, KStdVector<VTableElement>(interfaceVTableSize));
       } else {
         auto const& interfaceVTable = interfaceVTablesIt->second;
         RuntimeAssert(interfaceVTable.size() == interfaceVTableSize, "");

runtime/src/main/cpp/Porting.cpp

@@ -85,7 +85,7 @@ int getLastErrorMessage(char* message, uint32_t size) {
     auto errMsgBufSize = size / 4;
     wchar_t errMsgBuffer[errMsgBufSize];
     ::FormatMessageW(flags, NULL, errCode, 0, errMsgBuffer, errMsgBufSize, NULL);
-    auto errMsgLength = ::WideCharToMultiByte(CP_UTF8, 0, errMsgBuffer, -1, message, size, NULL, NULL);
+    ::WideCharToMultiByte(CP_UTF8, 0, errMsgBuffer, -1, message, size, NULL, NULL);
   }
   return errCode;
 }
@@ -108,7 +108,6 @@ int32_t consoleReadUtf8(void* utf8, uint32_t maxSizeBytes) {
       if (!length && KonanNeedDebugInfo) {
         char msg[512];
         auto errCode = getLastErrorMessage(msg, sizeof(msg));
-        char buffer[1024];
         consoleErrorf("UTF-16 to UTF-8 conversion error %d: %s", errCode, msg);
       }
       ((char*) utf8)[length] = 0;

runtime/src/main/cpp/Worker.cpp

@@ -165,11 +165,6 @@ class Worker {
   pthread_t thread_ = 0;
 };
 
-#else  // WITH_WORKERS
-class Worker {
-  KInt id;
-};
-
 #endif  // WITH_WORKERS
 
 namespace {
@@ -407,7 +402,6 @@ class State {
   }
 
   OBJ_GETTER(getWorkerNameUnlocked, KInt id) {
-    Worker* worker = nullptr;
     ObjHolder nameHolder;
     {
       Locker locker(&lock_);
@@ -566,7 +560,6 @@ KInt currentWorker() {
 }
 
 KInt execute(KInt id, KInt transferMode, KRef producer, KNativePtr jobFunction) {
-  Job job;
   ObjHolder holder;
   WorkerLaunchpad(producer, holder.slot());
   KNativePtr jobArgument = transfer(&holder, transferMode);