[wasm] Remove some small TODOs and small fixes.

R=clemensh@chromium.org,ahaas@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2963603003
Cr-Commit-Position: refs/heads/master@{#46283}

src/wasm/wasm-js.cc

@@ -121,7 +121,6 @@ i::wasm::ModuleWireBytes GetFirstArgumentAsBytes(
                         i::wasm::kV8MaxWasmModuleSize, length);
   }
   if (thrower->error()) return i::wasm::ModuleWireBytes(nullptr, nullptr);
-  // TODO(titzer): use the handle as well?
   return i::wasm::ModuleWireBytes(start, start + length);
 }
 
@@ -839,12 +838,10 @@ Handle<JSFunction> InstallGetter(Isolate* isolate, Handle<JSObject> object,
 void WasmJs::Install(Isolate* isolate) {
   Handle<JSGlobalObject> global = isolate->global_object();
   Handle<Context> context(global->native_context(), isolate);
-  // TODO(titzer): once FLAG_expose_wasm is gone, this should become a DCHECK.
+  // Check if the map is already installed and do nothing otherwise.
   if (context->get(Context::WASM_FUNCTION_MAP_INDEX)->IsMap()) return;
 
   // Install Maps.
-
-  // TODO(titzer): Also make one for strict mode functions?
   Handle<Map> prev_map = Handle<Map>(context->sloppy_function_map(), isolate);
 
   InstanceType instance_type = prev_map->instance_type();

src/wasm/wasm-module.cc

@@ -358,7 +358,7 @@ WasmInstanceObject* wasm::GetOwningWasmInstance(Code* code) {
 }
 
 WasmModule::WasmModule(std::unique_ptr<Zone> owned)
-    : signature_zone(std::move(owned)), pending_tasks(new base::Semaphore(0)) {}
+    : signature_zone(std::move(owned)) {}
 
 WasmFunction* wasm::GetWasmFunctionForImportWrapper(Isolate* isolate,
                                                     Handle<Object> target) {

src/wasm/wasm-module.h

@@ -183,14 +183,6 @@ struct V8_EXPORT_PRIVATE WasmModule {
   std::vector<WasmImport> import_table;        // import table.
   std::vector<WasmExport> export_table;        // export table.
   std::vector<WasmTableInit> table_inits;      // initializations of tables
-  // We store the semaphore here to extend its lifetime. In <libc-2.21, which we
-  // use on the try bots, semaphore::Wait() can return while some compilation
-  // tasks are still executing semaphore::Signal(). If the semaphore is cleaned
-  // up right after semaphore::Wait() returns, then this can cause an
-  // invalid-semaphore error in the compilation tasks.
-  // TODO(wasm): Move this semaphore back to CompileInParallel when the try bots
-  // switch to libc-2.21 or higher.
-  std::unique_ptr<base::Semaphore> pending_tasks;
 
   WasmModule() : WasmModule(nullptr) {}
   WasmModule(std::unique_ptr<Zone> owned);

src/wasm/wasm-objects.cc

@@ -271,7 +271,7 @@ Handle<FixedArray> WasmTableObject::AddDispatchTable(
   if (instance.is_null()) return dispatch_tables;
   // TODO(titzer): use weak cells here to avoid leaking instances.
 
-  // Grow the dispatch table and add a new triple at the end.
+  // Grow the dispatch table and add a new entry at the end.
   Handle<FixedArray> new_dispatch_tables =
       isolate->factory()->CopyFixedArrayAndGrow(dispatch_tables, 4);
 
@@ -360,9 +360,9 @@ Handle<JSArrayBuffer> GrowMemoryBuffer(Isolate* isolate,
 
   // TODO(gdeepti): Change the protection here instead of allocating a new
   // buffer before guard regions are turned on, see issue #5886.
-  const bool enable_guard_regions =
-      (old_buffer.is_null() && EnableGuardRegions()) ||
-      (!old_buffer.is_null() && old_buffer->has_guard_region());
+  const bool enable_guard_regions = old_buffer.is_null()
+                                        ? EnableGuardRegions()
+                                        : old_buffer->has_guard_region();
   size_t new_size =
       static_cast<size_t>(old_pages + pages) * WasmModule::kPageSize;
   Handle<JSArrayBuffer> new_buffer =

src/wasm/wasm-opcodes.cc

@@ -399,13 +399,6 @@ FunctionSig* WasmOpcodes::AtomicSignature(WasmOpcode opcode) {
       kSimpleExprSigs[kAtomicExprSigTable[opcode & 0xff]]);
 }
 
-// TODO(titzer): pull WASM_64 up to a common header.
-#if !V8_TARGET_ARCH_32_BIT || V8_TARGET_ARCH_X64
-#define WASM_64 1
-#else
-#define WASM_64 0
-#endif
-
 int WasmOpcodes::TrapReasonToMessageId(TrapReason reason) {
   switch (reason) {
 #define TRAPREASON_TO_MESSAGE(name) \