[wasm] Print function name in disassembly

We already have some logic to try to get a reasonable name for the
function when logging code. It looks up the name custom section, and
falls back to the function index. Extract this into a helper, and call
it when disassembly the code.

Bug: v8:12098
Change-Id: Ieebe6594bc3184fa655f878faa0cb67c248d7f56
Fixed: v8:12098
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3125355Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76769}

src/wasm/wasm-code-manager.cc

@@ -217,40 +217,23 @@ bool WasmCode::ShouldBeLogged(Isolate* isolate) {
          isolate->is_profiling();
 }
 
-void WasmCode::LogCode(Isolate* isolate, const char* source_url,
-                       int script_id) const {
-  DCHECK(ShouldBeLogged(isolate));
-  if (IsAnonymous()) return;
+std::string WasmCode::DebugName() const {
+  if (IsAnonymous()) {
+    return "anonymous function";
+  }
 
-  ModuleWireBytes wire_bytes(native_module_->wire_bytes());
-  const WasmModule* module = native_module_->module();
+  ModuleWireBytes wire_bytes(native_module()->wire_bytes());
+  const WasmModule* module = native_module()->module();
   WireBytesRef name_ref =
       module->lazily_generated_names.LookupFunctionName(wire_bytes, index());
   WasmName name = wire_bytes.GetNameOrNull(name_ref);
-
-  const WasmDebugSymbols& debug_symbols = module->debug_symbols;
-  auto load_wasm_source_map = isolate->wasm_load_source_map_callback();
-  auto source_map = native_module_->GetWasmSourceMap();
-  if (!source_map && debug_symbols.type == WasmDebugSymbols::Type::SourceMap &&
-      !debug_symbols.external_url.is_empty() && load_wasm_source_map) {
-    WasmName external_url =
-        wire_bytes.GetNameOrNull(debug_symbols.external_url);
-    std::string external_url_string(external_url.data(), external_url.size());
-    HandleScope scope(isolate);
-    v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
-    Local<v8::String> source_map_str =
-        load_wasm_source_map(v8_isolate, external_url_string.c_str());
-    native_module_->SetWasmSourceMap(
-        std::make_unique<WasmModuleSourceMap>(v8_isolate, source_map_str));
-  }
-
   std::string name_buffer;
   if (kind() == kWasmToJsWrapper) {
     name_buffer = "wasm-to-js:";
     size_t prefix_len = name_buffer.size();
     constexpr size_t kMaxSigLength = 128;
     name_buffer.resize(prefix_len + kMaxSigLength);
-    const FunctionSig* sig = module->functions[index_].sig;
+    const FunctionSig* sig = module->functions[index()].sig;
     size_t sig_length = PrintSignature(
         base::VectorOf(&name_buffer[prefix_len], kMaxSigLength), sig);
     name_buffer.resize(prefix_len + sig_length);
@@ -259,13 +242,41 @@ void WasmCode::LogCode(Isolate* isolate, const char* source_url,
       name_buffer += '-';
       name_buffer.append(name.begin(), name.size());
     }
-    name = base::VectorOf(name_buffer);
   } else if (name.empty()) {
     name_buffer.resize(32);
     name_buffer.resize(
         SNPrintF(base::VectorOf(&name_buffer.front(), name_buffer.size()),
                  "wasm-function[%d]", index()));
-    name = base::VectorOf(name_buffer);
+  } else {
+    name_buffer.append(name.begin(), name.end());
+  }
+  return name_buffer;
+}
+
+void WasmCode::LogCode(Isolate* isolate, const char* source_url,
+                       int script_id) const {
+  DCHECK(ShouldBeLogged(isolate));
+  if (IsAnonymous()) return;
+
+  ModuleWireBytes wire_bytes(native_module_->wire_bytes());
+  const WasmModule* module = native_module_->module();
+  std::string fn_name = DebugName();
+  WasmName name = base::VectorOf(fn_name);
+
+  const WasmDebugSymbols& debug_symbols = module->debug_symbols;
+  auto load_wasm_source_map = isolate->wasm_load_source_map_callback();
+  auto source_map = native_module_->GetWasmSourceMap();
+  if (!source_map && debug_symbols.type == WasmDebugSymbols::Type::SourceMap &&
+      !debug_symbols.external_url.is_empty() && load_wasm_source_map) {
+    WasmName external_url =
+        wire_bytes.GetNameOrNull(debug_symbols.external_url);
+    std::string external_url_string(external_url.data(), external_url.size());
+    HandleScope scope(isolate);
+    v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
+    Local<v8::String> source_map_str =
+        load_wasm_source_map(v8_isolate, external_url_string.c_str());
+    native_module_->SetWasmSourceMap(
+        std::make_unique<WasmModuleSourceMap>(v8_isolate, source_map_str));
   }
 
   // Record source positions before adding code, otherwise when code is added,
@@ -334,7 +345,7 @@ void WasmCode::Validate() const {
 #endif
 }
 
-void WasmCode::MaybePrint(const char* name) const {
+void WasmCode::MaybePrint() const {
   // Determines whether flags want this code to be printed.
   bool function_index_matches =
       (!IsAnonymous() &&
@@ -342,7 +353,8 @@ void WasmCode::MaybePrint(const char* name) const {
   if (FLAG_print_code ||
       (kind() == kFunction ? (FLAG_print_wasm_code || function_index_matches)
                            : FLAG_print_wasm_stub_code)) {
-    Print(name);
+    std::string name = DebugName();
+    Print(name.c_str());
   }
 }
 
@@ -1255,6 +1267,7 @@ std::unique_ptr<WasmCode> NativeModule::AddCodeWithCodeSpace(
       safepoint_table_offset, handler_table_offset, constant_pool_offset,
       code_comments_offset, instr_size, protected_instructions_data, reloc_info,
       source_position_table, kind, tier, for_debugging}};
+
   code->MaybePrint();
   code->Validate();
 

src/wasm/wasm-code-manager.h

@@ -318,7 +318,7 @@ class V8_EXPORT_PRIVATE WasmCode final {
 
   void Validate() const;
   void Print(const char* name = nullptr) const;
-  void MaybePrint(const char* name = nullptr) const;
+  void MaybePrint() const;
   void Disassemble(const char* name, std::ostream& os,
                    Address current_pc = kNullAddress) const;
 
@@ -420,6 +420,10 @@ class V8_EXPORT_PRIVATE WasmCode final {
   std::unique_ptr<const byte[]> ConcatenateBytes(
       std::initializer_list<base::Vector<const byte>>);
 
+  // Tries to get a reasonable name. Lazily looks up the name section, and falls
+  // back to the function index. Return value is guaranteed to not be empty.
+  std::string DebugName() const;
+
   // Code objects that have been registered with the global trap handler within
   // this process, will have a {trap_handler_index} associated with them.
   int trap_handler_index() const {