[wasm] Ensure constness of WasmModule after decoding

We pass the {WasmModule} by non-const pointer and by non-const
reference a lot. This violates the style guide, and adds the risk of
accidentally modifying it.
This CL makes the {WasmModule} const during compilation and
instantiation.

R=mstarzinger@chromium.org

Bug: v8:7754
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: Ie1878322828b63284b341d97da595e8e91dd4f51
Reviewed-on: https://chromium-review.googlesource.com/1117194Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54078}

src/api.cc

@@ -9450,7 +9450,7 @@ int debug::WasmScript::NumFunctions() const {
   DCHECK_EQ(i::Script::TYPE_WASM, script->type());
   i::WasmModuleObject* module_object =
       i::WasmModuleObject::cast(script->wasm_module_object());
-  i::wasm::WasmModule* module = module_object->module();
+  const i::wasm::WasmModule* module = module_object->module();
   DCHECK_GE(i::kMaxInt, module->functions.size());
   return static_cast<int>(module->functions.size());
 }
@@ -9461,7 +9461,7 @@ int debug::WasmScript::NumImportedFunctions() const {
   DCHECK_EQ(i::Script::TYPE_WASM, script->type());
   i::WasmModuleObject* module_object =
       i::WasmModuleObject::cast(script->wasm_module_object());
-  i::wasm::WasmModule* module = module_object->module();
+  const i::wasm::WasmModule* module = module_object->module();
   DCHECK_GE(i::kMaxInt, module->num_imported_functions);
   return static_cast<int>(module->num_imported_functions);
 }
@@ -9473,10 +9473,10 @@ std::pair<int, int> debug::WasmScript::GetFunctionRange(
   DCHECK_EQ(i::Script::TYPE_WASM, script->type());
   i::WasmModuleObject* module_object =
       i::WasmModuleObject::cast(script->wasm_module_object());
-  i::wasm::WasmModule* module = module_object->module();
+  const i::wasm::WasmModule* module = module_object->module();
   DCHECK_LE(0, function_index);
   DCHECK_GT(module->functions.size(), function_index);
-  i::wasm::WasmFunction& func = module->functions[function_index];
+  const i::wasm::WasmFunction& func = module->functions[function_index];
   DCHECK_GE(i::kMaxInt, func.code.offset());
   DCHECK_GE(i::kMaxInt, func.code.end_offset());
   return std::make_pair(static_cast<int>(func.code.offset()),
@@ -9489,10 +9489,10 @@ uint32_t debug::WasmScript::GetFunctionHash(int function_index) {
   DCHECK_EQ(i::Script::TYPE_WASM, script->type());
   i::WasmModuleObject* module_object =
       i::WasmModuleObject::cast(script->wasm_module_object());
-  i::wasm::WasmModule* module = module_object->module();
+  const i::wasm::WasmModule* module = module_object->module();
   DCHECK_LE(0, function_index);
   DCHECK_GT(module->functions.size(), function_index);
-  i::wasm::WasmFunction& func = module->functions[function_index];
+  const i::wasm::WasmFunction& func = module->functions[function_index];
   i::wasm::ModuleWireBytes wire_bytes(
       module_object->native_module()->wire_bytes());
   i::Vector<const i::byte> function_bytes = wire_bytes.GetFunctionBytes(&func);

src/compiler/wasm-compiler.cc

@@ -4721,7 +4721,7 @@ class WasmWrapperGraphBuilder : public WasmGraphBuilder {
 }  // namespace
 
 MaybeHandle<Code> CompileJSToWasmWrapper(
-    Isolate* isolate, wasm::WasmModule* module, Address call_target,
+    Isolate* isolate, const wasm::WasmModule* module, Address call_target,
     uint32_t index, wasm::UseTrapHandler use_trap_handler) {
   const wasm::WasmFunction* func = &module->functions[index];
 

src/compiler/wasm-compiler.h

@@ -116,7 +116,7 @@ MaybeHandle<Code> CompileWasmToJSWrapper(Isolate*, Handle<JSReceiver> target,
 
 // Wraps a given wasm code object, producing a code object.
 V8_EXPORT_PRIVATE MaybeHandle<Code> CompileJSToWasmWrapper(
-    Isolate*, wasm::WasmModule*, Address call_target, uint32_t index,
+    Isolate*, const wasm::WasmModule*, Address call_target, uint32_t index,
     wasm::UseTrapHandler);
 
 // Compiles a stub that redirects a call to a wasm function to the wasm

src/wasm/module-compiler.cc

@@ -188,7 +188,7 @@ namespace {
 class JSToWasmWrapperCache {
  public:
   Handle<Code> CloneOrCompileJSToWasmWrapper(
-      Isolate* isolate, wasm::WasmModule* module, Address call_target,
+      Isolate* isolate, const wasm::WasmModule* module, Address call_target,
       uint32_t index, wasm::UseTrapHandler use_trap_handler) {
     const bool is_import = index < module->num_imported_functions;
     DCHECK_EQ(is_import, call_target == kNullAddress);
@@ -259,7 +259,7 @@ class InstanceBuilder {
   };
 
   Isolate* isolate_;
-  WasmModule* const module_;
+  const WasmModule* const module_;
   const std::shared_ptr<Counters> async_counters_;
   ErrorThrower* thrower_;
   Handle<WasmModuleObject> module_object_;
@@ -320,8 +320,9 @@ class InstanceBuilder {
   // Load data segments into the memory.
   void LoadDataSegments(Handle<WasmInstanceObject> instance);
 
-  void WriteGlobalValue(WasmGlobal& global, double value);
-  void WriteGlobalValue(WasmGlobal& global, Handle<WasmGlobalObject> value);
+  void WriteGlobalValue(const WasmGlobal& global, double value);
+  void WriteGlobalValue(const WasmGlobal& global,
+                        Handle<WasmGlobalObject> value);
 
   void SanitizeImports();
 
@@ -335,7 +336,7 @@ class InstanceBuilder {
   int ProcessImports(Handle<WasmInstanceObject> instance);
 
   template <typename T>
-  T* GetRawGlobalPtr(WasmGlobal& global);
+  T* GetRawGlobalPtr(const WasmGlobal& global);
 
   // Process initialization of globals.
   void InitGlobals();
@@ -934,10 +935,11 @@ class BackgroundCompileTask : public CancelableTask {
 }  // namespace
 
 MaybeHandle<WasmModuleObject> CompileToModuleObject(
-    Isolate* isolate, ErrorThrower* thrower, std::shared_ptr<WasmModule> module,
-    const ModuleWireBytes& wire_bytes, Handle<Script> asm_js_script,
+    Isolate* isolate, ErrorThrower* thrower,
+    std::shared_ptr<const WasmModule> module, const ModuleWireBytes& wire_bytes,
+    Handle<Script> asm_js_script,
     Vector<const byte> asm_js_offset_table_bytes) {
-  WasmModule* wasm_module = module.get();
+  const WasmModule* wasm_module = module.get();
   TimedHistogramScope wasm_compile_module_time_scope(
       SELECT_WASM_COUNTER(isolate->async_counters(), wasm_module->origin,
                           wasm_compile, module_time));
@@ -1218,7 +1220,7 @@ MaybeHandle<WasmInstanceObject> InstanceBuilder::Build() {
   //--------------------------------------------------------------------------
   // Check that indirect function table segments are within bounds.
   //--------------------------------------------------------------------------
-  for (WasmTableInit& table_init : module_->table_inits) {
+  for (const WasmTableInit& table_init : module_->table_inits) {
     DCHECK(table_init.table_index < table_instances_.size());
     uint32_t base = EvalUint32InitExpr(table_init.offset);
     size_t table_size = table_instances_[table_init.table_index].table_size;
@@ -1231,7 +1233,7 @@ MaybeHandle<WasmInstanceObject> InstanceBuilder::Build() {
   //--------------------------------------------------------------------------
   // Check that memory segments are within bounds.
   //--------------------------------------------------------------------------
-  for (WasmDataSegment& seg : module_->data_segments) {
+  for (const WasmDataSegment& seg : module_->data_segments) {
     uint32_t base = EvalUint32InitExpr(seg.dest_addr);
     if (!in_bounds(base, seg.source.length(), instance->memory_size())) {
       thrower_->LinkError("data segment is out of bounds");
@@ -1430,7 +1432,7 @@ void InstanceBuilder::LoadDataSegments(Handle<WasmInstanceObject> instance) {
   }
 }
 
-void InstanceBuilder::WriteGlobalValue(WasmGlobal& global, double num) {
+void InstanceBuilder::WriteGlobalValue(const WasmGlobal& global, double num) {
   TRACE("init [globals_start=%p + %u] = %lf, type = %s\n",
         reinterpret_cast<void*>(raw_buffer_ptr(globals_, 0)), global.offset,
         num, ValueTypes::TypeName(global.type));
@@ -1453,7 +1455,7 @@ void InstanceBuilder::WriteGlobalValue(WasmGlobal& global, double num) {
   }
 }
 
-void InstanceBuilder::WriteGlobalValue(WasmGlobal& global,
+void InstanceBuilder::WriteGlobalValue(const WasmGlobal& global,
                                        Handle<WasmGlobalObject> value) {
   TRACE("init [globals_start=%p + %u] = ",
         reinterpret_cast<void*>(raw_buffer_ptr(globals_, 0)), global.offset);
@@ -1493,7 +1495,7 @@ void InstanceBuilder::SanitizeImports() {
   Vector<const uint8_t> wire_bytes =
       module_object_->native_module()->wire_bytes();
   for (size_t index = 0; index < module_->import_table.size(); ++index) {
-    WasmImport& import = module_->import_table[index];
+    const WasmImport& import = module_->import_table[index];
 
     Handle<String> module_name;
     MaybeHandle<String> maybe_module_name =
@@ -1559,7 +1561,7 @@ int InstanceBuilder::ProcessImports(Handle<WasmInstanceObject> instance) {
   int num_imports = static_cast<int>(module_->import_table.size());
   NativeModule* native_module = instance->module_object()->native_module();
   for (int index = 0; index < num_imports; ++index) {
-    WasmImport& import = module_->import_table[index];
+    const WasmImport& import = module_->import_table[index];
 
     Handle<String> module_name = sanitized_imports_[index].module_name;
     Handle<String> import_name = sanitized_imports_[index].import_name;
@@ -1622,7 +1624,8 @@ int InstanceBuilder::ProcessImports(Handle<WasmInstanceObject> instance) {
         }
         uint32_t table_num = import.index;
         DCHECK_EQ(table_num, num_imported_tables);
-        WasmIndirectFunctionTable& table = module_->function_tables[table_num];
+        const WasmIndirectFunctionTable& table =
+            module_->function_tables[table_num];
         TableInstance& table_instance = table_instances_[table_num];
         table_instance.table_object = Handle<WasmTableObject>::cast(value);
         instance->set_table_object(*table_instance.table_object);
@@ -1746,7 +1749,7 @@ int InstanceBuilder::ProcessImports(Handle<WasmInstanceObject> instance) {
         // Mutable global imports instead have their backing array buffers
         // referenced by this instance, and store the address of the imported
         // global in the {imported_mutable_globals_} array.
-        WasmGlobal& global = module_->globals[import.index];
+        const WasmGlobal& global = module_->globals[import.index];
 
         // The mutable-global proposal allows importing i64 values, but only if
         // they are passed as a WebAssembly.Global object.
@@ -1839,7 +1842,7 @@ int InstanceBuilder::ProcessImports(Handle<WasmInstanceObject> instance) {
 }
 
 template <typename T>
-T* InstanceBuilder::GetRawGlobalPtr(WasmGlobal& global) {
+T* InstanceBuilder::GetRawGlobalPtr(const WasmGlobal& global) {
   return reinterpret_cast<T*>(raw_buffer_ptr(globals_, global.offset));
 }
 
@@ -1931,7 +1934,7 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
     // imported WebAssembly functions into the js_wrappers_ list.
     for (int index = 0, end = static_cast<int>(module_->import_table.size());
          index < end; ++index) {
-      WasmImport& import = module_->import_table[index];
+      const WasmImport& import = module_->import_table[index];
       if (import.kind == kExternalFunction) {
         Handle<Object> value = sanitized_imports_[index].value;
         if (WasmExportedFunction::IsWasmExportedFunction(*value)) {
@@ -1971,7 +1974,7 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
 
   // Process each export in the export table.
   int export_index = 0;  // Index into {export_wrappers}.
-  for (WasmExport& exp : module_->export_table) {
+  for (const WasmExport& exp : module_->export_table) {
     Handle<String> name = WasmModuleObject::ExtractUtf8StringFromModuleBytes(
                               isolate_, module_object_, exp.name)
                               .ToHandleChecked();
@@ -1986,7 +1989,7 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
     switch (exp.kind) {
       case kExternalFunction: {
         // Wrap and export the code as a JSFunction.
-        WasmFunction& function = module_->functions[exp.index];
+        const WasmFunction& function = module_->functions[exp.index];
         Handle<JSFunction> js_function = js_wrappers_[exp.index];
         if (js_function.is_null()) {
           // Wrap the exported code as a JSFunction.
@@ -2014,7 +2017,8 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
       case kExternalTable: {
         // Export a table as a WebAssembly.Table object.
         TableInstance& table_instance = table_instances_[exp.index];
-        WasmIndirectFunctionTable& table = module_->function_tables[exp.index];
+        const WasmIndirectFunctionTable& table =
+            module_->function_tables[exp.index];
         if (table_instance.table_object.is_null()) {
           uint32_t maximum = table.has_maximum_size ? table.maximum_size
                                                     : FLAG_wasm_max_table_size;
@@ -2035,7 +2039,7 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
         break;
       }
       case kExternalGlobal: {
-        WasmGlobal& global = module_->globals[exp.index];
+        const WasmGlobal& global = module_->globals[exp.index];
         if (FLAG_experimental_wasm_mut_global) {
           Handle<JSArrayBuffer> buffer;
           uint32_t offset;
@@ -2119,7 +2123,7 @@ void InstanceBuilder::ProcessExports(Handle<WasmInstanceObject> instance) {
 void InstanceBuilder::InitializeTables(Handle<WasmInstanceObject> instance) {
   size_t table_count = module_->function_tables.size();
   for (size_t index = 0; index < table_count; ++index) {
-    WasmIndirectFunctionTable& table = module_->function_tables[index];
+    const WasmIndirectFunctionTable& table = module_->function_tables[index];
     TableInstance& table_instance = table_instances_[index];
 
     if (!instance->has_indirect_function_table()) {
@@ -2144,7 +2148,7 @@ void InstanceBuilder::LoadTableSegments(Handle<WasmInstanceObject> instance) {
       DCHECK(in_bounds(base, num_entries, table_instance.table_size));
       for (uint32_t i = 0; i < num_entries; ++i) {
         uint32_t func_index = table_init.entries[i];
-        WasmFunction* function = &module_->functions[func_index];
+        const WasmFunction* function = &module_->functions[func_index];
         int table_index = static_cast<int>(i + base);
 
         // Update the local dispatch table first.
@@ -2484,7 +2488,7 @@ class AsyncCompileJob::PrepareAndStartCompile : public CompileStep {
     Handle<Script> script = CreateWasmScript(job_->isolate_, job_->wire_bytes_);
     Handle<ByteArray> asm_js_offset_table;
 
-    WasmModule* module = job_->module_.get();
+    const WasmModule* module = job_->module_.get();
     ModuleEnv env = CreateDefaultModuleEnv(module);
     int export_wrapper_size = static_cast<int>(module->num_exported_functions);
     Handle<FixedArray> export_wrappers =
@@ -3100,7 +3104,7 @@ void CompileJsToWasmWrappers(Isolate* isolate,
   NativeModule* native_module = module_object->native_module();
   wasm::UseTrapHandler use_trap_handler =
       native_module->use_trap_handler() ? kUseTrapHandler : kNoTrapHandler;
-  WasmModule* module = module_object->module();
+  const WasmModule* module = module_object->module();
   for (auto exp : module->export_table) {
     if (exp.kind != kExternalFunction) continue;
     Address call_target =

src/wasm/module-compiler.h

@@ -48,9 +48,9 @@ std::unique_ptr<CompilationState, CompilationStateDeleter> NewCompilationState(
 ModuleEnv* GetModuleEnv(CompilationState* compilation_state);
 
 MaybeHandle<WasmModuleObject> CompileToModuleObject(
-    Isolate* isolate, ErrorThrower* thrower, std::shared_ptr<WasmModule> module,
-    const ModuleWireBytes& wire_bytes, Handle<Script> asm_js_script,
-    Vector<const byte> asm_js_offset_table_bytes);
+    Isolate* isolate, ErrorThrower* thrower,
+    std::shared_ptr<const WasmModule> module, const ModuleWireBytes& wire_bytes,
+    Handle<Script> asm_js_script, Vector<const byte> asm_js_offset_table_bytes);
 
 MaybeHandle<WasmInstanceObject> InstantiateToInstanceObject(
     Isolate* isolate, ErrorThrower* thrower,
@@ -148,7 +148,7 @@ class AsyncCompileJob {
   ModuleWireBytes wire_bytes_;
   Handle<Context> context_;
   std::unique_ptr<CompilationResultResolver> resolver_;
-  std::shared_ptr<WasmModule> module_;
+  std::shared_ptr<const WasmModule> module_;
 
   std::vector<DeferredHandles*> deferred_handles_;
   Handle<WasmModuleObject> module_object_;

src/wasm/wasm-debug.cc

@@ -612,7 +612,7 @@ void WasmDebugInfo::RedirectToInterpreter(Handle<WasmDebugInfo> debug_info,
   Handle<WasmInstanceObject> instance(debug_info->wasm_instance(), isolate);
   wasm::NativeModule* native_module =
       instance->module_object()->native_module();
-  wasm::WasmModule* module = instance->module();
+  const wasm::WasmModule* module = instance->module();
 
   // We may modify js wrappers, as well as wasm functions. Hence the 2
   // modification scopes.

src/wasm/wasm-module.cc

@@ -129,7 +129,7 @@ Handle<JSArray> GetImports(Isolate* isolate,
   Handle<String> global_string = factory->InternalizeUtf8String("global");
 
   // Create the result array.
-  WasmModule* module = module_object->module();
+  const WasmModule* module = module_object->module();
   int num_imports = static_cast<int>(module->import_table.size());
   Handle<JSArray> array_object = factory->NewJSArray(PACKED_ELEMENTS, 0, 0);
   Handle<FixedArray> storage = factory->NewFixedArray(num_imports);
@@ -141,7 +141,7 @@ Handle<JSArray> GetImports(Isolate* isolate,
 
   // Populate the result array.
   for (int index = 0; index < num_imports; ++index) {
-    WasmImport& import = module->import_table[index];
+    const WasmImport& import = module->import_table[index];
 
     Handle<JSObject> entry = factory->NewJSObject(object_function);
 
@@ -196,7 +196,7 @@ Handle<JSArray> GetExports(Isolate* isolate,
   Handle<String> global_string = factory->InternalizeUtf8String("global");
 
   // Create the result array.
-  WasmModule* module = module_object->module();
+  const WasmModule* module = module_object->module();
   int num_exports = static_cast<int>(module->export_table.size());
   Handle<JSArray> array_object = factory->NewJSArray(PACKED_ELEMENTS, 0, 0);
   Handle<FixedArray> storage = factory->NewFixedArray(num_exports);
@@ -208,7 +208,7 @@ Handle<JSArray> GetExports(Isolate* isolate,
 
   // Populate the result array.
   for (int index = 0; index < num_exports; ++index) {
-    WasmExport& exp = module->export_table[index];
+    const WasmExport& exp = module->export_table[index];
 
     Handle<String> export_kind;
     switch (exp.kind) {

src/wasm/wasm-objects-inl.h

@@ -52,7 +52,7 @@ CAST_ACCESSOR(WasmTableObject)
 ACCESSORS(WasmModuleObject, managed_native_module, Managed<wasm::NativeModule>,
           kNativeModuleOffset)
 ACCESSORS(WasmModuleObject, export_wrappers, FixedArray, kExportWrappersOffset)
-ACCESSORS(WasmModuleObject, managed_module, Managed<wasm::WasmModule>,
+ACCESSORS(WasmModuleObject, managed_module, Managed<const wasm::WasmModule>,
           kManagedModuleOffset)
 ACCESSORS(WasmModuleObject, script, Script, kScriptOffset)
 ACCESSORS(WasmModuleObject, weak_instance_list, WeakArrayList,
@@ -61,7 +61,7 @@ OPTIONAL_ACCESSORS(WasmModuleObject, asm_js_offset_table, ByteArray,
                    kAsmJsOffsetTableOffset)
 OPTIONAL_ACCESSORS(WasmModuleObject, breakpoint_infos, FixedArray,
                    kBreakPointInfosOffset)
-wasm::WasmModule* WasmModuleObject::module() const {
+const wasm::WasmModule* WasmModuleObject::module() const {
   return managed_module()->raw();
 }
 wasm::NativeModule* WasmModuleObject::native_module() {

src/wasm/wasm-objects.cc

@@ -176,16 +176,16 @@ enum DispatchTableElements : int {
 
 Handle<WasmModuleObject> WasmModuleObject::New(
     Isolate* isolate, Handle<FixedArray> export_wrappers,
-    std::shared_ptr<wasm::WasmModule> shared_module, wasm::ModuleEnv& env,
+    std::shared_ptr<const wasm::WasmModule> shared_module, wasm::ModuleEnv& env,
     std::unique_ptr<const uint8_t[]> wire_bytes, size_t wire_bytes_len,
     Handle<Script> script, Handle<ByteArray> asm_js_offset_table) {
-  WasmModule* module = shared_module.get();
+  const WasmModule* module = shared_module.get();
   DCHECK_EQ(module, env.module);
   size_t module_size = EstimateWasmModuleSize(module);
   // The {managed_module} will take shared ownership of the {WasmModule} object,
   // and release it when the GC reclaim the managed.
-  Handle<Managed<WasmModule>> managed_module =
-      Managed<WasmModule>::FromSharedPtr(isolate, module_size,
+  Handle<Managed<const WasmModule>> managed_module =
+      Managed<const WasmModule>::FromSharedPtr(isolate, module_size,
                                                std::move(shared_module));
 
   // Now create the {WasmModuleObject}.
@@ -228,7 +228,7 @@ bool WasmModuleObject::SetBreakPoint(Handle<WasmModuleObject> module_object,
   // Find the function for this breakpoint.
   int func_index = module_object->GetContainingFunction(*position);
   if (func_index < 0) return false;
-  WasmFunction& func = module_object->module()->functions[func_index];
+  const WasmFunction& func = module_object->module()->functions[func_index];
   int offset_in_func = *position - func.code.offset();
 
   // According to the current design, we should only be called with valid
@@ -372,7 +372,7 @@ void WasmModuleObject::SetBreakpointsOnNewInstance(
     // Find the function for this breakpoint, and set the breakpoint.
     int func_index = module_object->GetContainingFunction(position);
     DCHECK_LE(0, func_index);
-    WasmFunction& func = module_object->module()->functions[func_index];
+    const WasmFunction& func = module_object->module()->functions[func_index];
     int offset_in_func = position - func.code.offset();
     WasmDebugInfo::SetBreakpoint(debug_info, func_index, offset_in_func);
   }
@@ -431,7 +431,8 @@ Handle<ByteArray> GetDecodedAsmJsOffsetTable(
   module_object->set_asm_js_offset_table(*decoded_table);
 
   int idx = 0;
-  std::vector<WasmFunction>& wasm_funs = module_object->module()->functions;
+  const std::vector<WasmFunction>& wasm_funs =
+      module_object->module()->functions;
   for (int func = 0; func < num_functions; ++func) {
     std::vector<wasm::AsmJsOffsetEntry>& func_asm_offsets =
         asm_offsets.val[func];
@@ -520,7 +521,7 @@ bool WasmModuleObject::GetPossibleBreakpoints(
     std::vector<v8::debug::BreakLocation>* locations) {
   DisallowHeapAllocation no_gc;
 
-  std::vector<WasmFunction>& functions = module()->functions;
+  const std::vector<WasmFunction>& functions = module()->functions;
   if (start.GetLineNumber() < 0 || start.GetColumnNumber() < 0 ||
       (!end.IsEmpty() &&
        (end.GetLineNumber() < 0 || end.GetColumnNumber() < 0)))
@@ -566,7 +567,7 @@ bool WasmModuleObject::GetPossibleBreakpoints(
 
   for (uint32_t func_idx = start_func_index; func_idx <= end_func_index;
        ++func_idx) {
-    WasmFunction& func = functions[func_idx];
+    const WasmFunction& func = functions[func_idx];
     if (func.code.length() == 0) continue;
 
     wasm::BodyLocalDecls locals(&tmp);
@@ -637,7 +638,7 @@ MaybeHandle<String> WasmModuleObject::ExtractUtf8StringFromModuleBytes(
 
 MaybeHandle<String> WasmModuleObject::GetModuleNameOrNull(
     Isolate* isolate, Handle<WasmModuleObject> module_object) {
-  WasmModule* module = module_object->module();
+  const WasmModule* module = module_object->module();
   if (!module->name.is_set()) return {};
   return ExtractUtf8StringFromModuleBytes(isolate, module_object, module->name);
 }
@@ -672,14 +673,14 @@ Vector<const uint8_t> WasmModuleObject::GetRawFunctionName(
 }
 
 int WasmModuleObject::GetFunctionOffset(uint32_t func_index) {
-  std::vector<WasmFunction>& functions = module()->functions;
+  const std::vector<WasmFunction>& functions = module()->functions;
   if (static_cast<uint32_t>(func_index) >= functions.size()) return -1;
   DCHECK_GE(kMaxInt, functions[func_index].code.offset());
   return static_cast<int>(functions[func_index].code.offset());
 }
 
 int WasmModuleObject::GetContainingFunction(uint32_t byte_offset) {
-  std::vector<WasmFunction>& functions = module()->functions;
+  const std::vector<WasmFunction>& functions = module()->functions;
 
   // Binary search for a function containing the given position.
   int left = 0;                                    // inclusive
@@ -694,7 +695,7 @@ int WasmModuleObject::GetContainingFunction(uint32_t byte_offset) {
     }
   }
   // If the found function does not contains the given position, return -1.
-  WasmFunction& func = functions[left];
+  const WasmFunction& func = functions[left];
   if (byte_offset < func.code.offset() ||
       byte_offset >= func.code.end_offset()) {
     return -1;
@@ -708,7 +709,7 @@ bool WasmModuleObject::GetPositionInfo(uint32_t position,
   int func_index = GetContainingFunction(position);
   if (func_index < 0) return false;
 
-  WasmFunction& function = module()->functions[func_index];
+  const WasmFunction& function = module()->functions[func_index];
 
   info->line = func_index;
   info->column = position - function.code.offset();
@@ -1188,7 +1189,9 @@ void WasmInstanceObject::SetRawMemory(byte* mem_start, uint32_t mem_size) {
   set_memory_mask(mem_mask64);
 }
 
-WasmModule* WasmInstanceObject::module() { return module_object()->module(); }
+const WasmModule* WasmInstanceObject::module() {
+  return module_object()->module();
+}
 
 Handle<WasmDebugInfo> WasmInstanceObject::GetOrCreateDebugInfo(
     Handle<WasmInstanceObject> instance) {

src/wasm/wasm-objects.h

@@ -107,8 +107,8 @@ class WasmModuleObject : public JSObject {
   DECL_ACCESSORS(managed_native_module, Managed<wasm::NativeModule>)
   inline wasm::NativeModule* native_module();
   DECL_ACCESSORS(export_wrappers, FixedArray)
-  DECL_ACCESSORS(managed_module, Managed<wasm::WasmModule>)
-  inline wasm::WasmModule* module() const;
+  DECL_ACCESSORS(managed_module, Managed<const wasm::WasmModule>)
+  inline const wasm::WasmModule* module() const;
   DECL_ACCESSORS(script, Script)
   DECL_ACCESSORS(weak_instance_list, WeakArrayList)
   DECL_OPTIONAL_ACCESSORS(asm_js_offset_table, ByteArray)
@@ -136,7 +136,7 @@ class WasmModuleObject : public JSObject {
 
   static Handle<WasmModuleObject> New(
       Isolate* isolate, Handle<FixedArray> export_wrappers,
-      std::shared_ptr<wasm::WasmModule> module, wasm::ModuleEnv& env,
+      std::shared_ptr<const wasm::WasmModule> module, wasm::ModuleEnv& env,
       std::unique_ptr<const uint8_t[]> wire_bytes, size_t wire_bytes_len,
       Handle<Script> script, Handle<ByteArray> asm_js_offset_table);
 
@@ -437,7 +437,7 @@ class WasmInstanceObject : public JSObject {
                                 WASM_INSTANCE_OBJECT_FIELDS)
 #undef WASM_INSTANCE_OBJECT_FIELDS
 
-  V8_EXPORT_PRIVATE wasm::WasmModule* module();
+  V8_EXPORT_PRIVATE const wasm::WasmModule* module();
 
   static bool EnsureIndirectFunctionTableWithMinimumSize(
       Handle<WasmInstanceObject> instance, uint32_t minimum_size);