[wasm] Make more central data structure move-only

This makes all data structures containing non-trivially-copyable fields
move-only, to prevent security and performance bugs.

Drive-by: Fix smaller performance bugs found by this refactoring.

R=titzer@chromium.org

Change-Id: I6802ac3591534c2ab5cacb2ca42b737f3b7fa801
Reviewed-on: https://chromium-review.googlesource.com/576170Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46747}

src/wasm/module-compiler.cc

@@ -1791,7 +1791,7 @@ void InstanceBuilder::LoadTableSegments(Handle<FixedArray> code_table,
     // compilation).
     std::unordered_map<uint32_t, uint32_t> num_table_exports;
     if (compile_lazy(module_)) {
-      for (auto table_init : module_->table_inits) {
+      for (auto& table_init : module_->table_inits) {
         for (uint32_t func_index : table_init.entries) {
           Code* code =
               Code::cast(code_table->get(static_cast<int>(func_index)));
@@ -1806,7 +1806,7 @@ void InstanceBuilder::LoadTableSegments(Handle<FixedArray> code_table,
 
     // TODO(titzer): this does redundant work if there are multiple tables,
     // since initializations are not sorted by table index.
-    for (auto table_init : module_->table_inits) {
+    for (auto& table_init : module_->table_inits) {
       uint32_t base = EvalUint32InitExpr(table_init.offset);
       uint32_t num_entries = static_cast<uint32_t>(table_init.entries.size());
       DCHECK(in_bounds(base, num_entries,

src/wasm/module-decoder.cc

@@ -660,8 +660,7 @@ class ModuleDecoder : public Decoder {
       WasmInitExpr offset = consume_init_expr(module_.get(), kWasmI32);
       uint32_t num_elem =
           consume_count("number of elements", kV8MaxWasmTableEntries);
-      std::vector<uint32_t> vector;
-      module_->table_inits.push_back({table_index, offset, vector});
+      module_->table_inits.emplace_back(table_index, offset);
       WasmTableInit* init = &module_->table_inits.back();
       for (uint32_t j = 0; j < num_elem; j++) {
         WasmFunction* func = nullptr;

src/wasm/wasm-debug.cc

@@ -169,7 +169,7 @@ class InterpreterHandle {
     SeqOneByteString* bytes_str =
         debug_info->wasm_instance()->compiled_module()->module_bytes();
     Vector<const byte> bytes(bytes_str->GetChars(), bytes_str->length());
-    return ModuleBytesEnv(instance->module, instance, bytes);
+    return {instance->module, instance, bytes};
   }
 
   WasmInterpreter* interpreter() { return &interpreter_; }

src/wasm/wasm-module.h

@@ -34,6 +34,15 @@ class CallDescriptor;
 namespace wasm {
 class ErrorThrower;
 
+// Use this in the private section to mark a struct move-only.
+#define WASM_MOVE_ONLY_STRUCT(name) \
+ public:                            \
+  name() = default;                 \
+  name(name&&) = default;           \
+                                    \
+ private:                           \
+  DISALLOW_COPY_AND_ASSIGN(name)
+
 enum WasmExternalKind {
   kExternalFunction = 0,
   kExternalTable = 1,
@@ -142,13 +151,22 @@ struct WasmIndirectFunctionTable {
   bool imported = false;        // true if imported.
   bool exported = false;        // true if exported.
   SignatureMap map;             // canonicalizing map for sig indexes.
+
+ private:
+  WASM_MOVE_ONLY_STRUCT(WasmIndirectFunctionTable);
 };
 
 // Static representation of how to initialize a table.
 struct WasmTableInit {
+  WasmTableInit(uint32_t table_index, WasmInitExpr offset)
+      : table_index(table_index), offset(offset) {}
+
   uint32_t table_index;
   WasmInitExpr offset;
   std::vector<uint32_t> entries;
+
+ private:
+  WASM_MOVE_ONLY_STRUCT(WasmTableInit);
 };
 
 // Static representation of a wasm import.
@@ -210,6 +228,8 @@ struct V8_EXPORT_PRIVATE WasmModule {
  private:
   // TODO(kschimpf) - Encapsulate more fields.
   ModuleOrigin origin_ = kWasmOrigin;  // origin of the module
+
+  DISALLOW_COPY_AND_ASSIGN(WasmModule);
 };
 
 typedef Managed<WasmModule> WasmModuleWrapper;
@@ -251,6 +271,9 @@ struct WasmInstance {
       code = handle(*code, isolate);
     }
   }
+
+ private:
+  WASM_MOVE_ONLY_STRUCT(WasmInstance);
 };
 
 // Interface to the storage (wire bytes) of a wasm module.
@@ -369,6 +392,9 @@ struct V8_EXPORT_PRIVATE ModuleEnv {
     DCHECK_NOT_NULL(instance);
     return instance->function_code[index];
   }
+
+ private:
+  WASM_MOVE_ONLY_STRUCT(ModuleEnv);
 };
 
 // A ModuleEnv together with ModuleWireBytes.
@@ -546,6 +572,9 @@ void ValidateModuleState(Isolate* isolate, Handle<WasmModuleObject> module_obj);
 void ValidateOrphanedInstance(Isolate* isolate,
                               Handle<WasmInstanceObject> instance);
 }  // namespace testing
+
+#undef WASM_MOVE_ONLY_STRUCT
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8