[inspector] Consistent frame function name in V8 Inspector and API.

On the way to a cheaper and more scalable stack frame representation
for the inspector (crbug/1258599), this removes the need to expose
both what was called "function name" and what was called "function
debug name" on a v8::StackFrame instance.

The reason to having a distinction between that the V8 API exposes
and what the inspector exposes as frame function name is that after
the initial refactoring around v8::internal::StackFrameInfo, some
wasm cctests would still dig into the implementation details and
insist on seeing the "function name" rather than the "function
debug name". This CL now addresses that detail in the wasm cctests
and going forward unifies the function names used by the inspector
and the V8 API (which is not only needed for internal consistency
and reduced storage requirements in the future, but also because
Blink for example uses v8 API and v8_inspector API interchangeably
and assumes that they agree, even though at this point Blink
luckily wasn't paying attention to the function name):

- The so-called "detailed stack trace", which is produced for the
  inspector and exposed by the v8 API, always yields the "function
  debug name" (which for example in case of wasm will be a WAT
  compatible name),
- while the so-called "simple stack trace", which is what is used
  to implement the CallSite API and underlies Error.stack continues
  to stick to the "function name" which in case of wasm is not
  WAT compatible).

Bug: chromium:1258599
Change-Id: Ib15d038f3ec893703d0f7b03f6e7573a38e82b39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3312274Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78283}

src/api/api.cc

@@ -44,6 +44,9 @@
 #include "src/common/globals.h"
 #include "src/compiler-dispatcher/lazy-compile-dispatcher.h"
 #include "src/date/date.h"
+#if V8_ENABLE_WEBASSEMBLY
+#include "src/debug/debug-wasm-objects.h"
+#endif  // V8_ENABLE_WEBASSEMBLY
 #include "src/debug/liveedit.h"
 #include "src/deoptimizer/deoptimizer.h"
 #include "src/diagnostics/gdb-jit.h"
@@ -3294,6 +3297,15 @@ Local<String> StackFrame::GetScriptSourceMappingURL() const {
 
 Local<String> StackFrame::GetFunctionName() const {
   auto self = Utils::OpenHandle(this);
+#if V8_ENABLE_WEBASSEMBLY
+  if (self->IsWasm()) {
+    auto isolate = self->GetIsolate();
+    auto instance = handle(self->GetWasmInstance(), isolate);
+    auto func_index = self->GetWasmFunctionIndex();
+    return Utils::ToLocal(
+        i::GetWasmFunctionDebugName(isolate, instance, func_index));
+  }
+#endif  // V8_ENABLE_WEBASSEMBLY
   auto name = i::StackFrameInfo::GetFunctionName(self);
   if (!name->IsString()) return {};
   return Local<String>::Cast(Utils::ToLocal(name));

src/debug/debug-interface.cc

@@ -49,20 +49,6 @@ v8_inspector::V8Inspector* GetInspector(Isolate* isolate) {
   return reinterpret_cast<i::Isolate*>(isolate)->inspector();
 }
 
-Local<String> GetFunctionDebugName(Local<StackFrame> frame) {
-#if V8_ENABLE_WEBASSEMBLY
-  auto info = Utils::OpenHandle(*frame);
-  if (info->IsWasm()) {
-    auto isolate = info->GetIsolate();
-    auto instance = handle(info->GetWasmInstance(), isolate);
-    auto func_index = info->GetWasmFunctionIndex();
-    return Utils::ToLocal(
-        i::GetWasmFunctionDebugName(isolate, instance, func_index));
-  }
-#endif  // V8_ENABLE_WEBASSEMBLY
-  return frame->GetFunctionName();
-}
-
 Local<String> GetFunctionDescription(Local<Function> function) {
   auto receiver = Utils::OpenHandle(*function);
   if (receiver->IsJSBoundFunction()) {

src/debug/debug-interface.h

@@ -49,13 +49,6 @@ int GetContextId(Local<Context> context);
 void SetInspector(Isolate* isolate, v8_inspector::V8Inspector*);
 v8_inspector::V8Inspector* GetInspector(Isolate* isolate);
 
-// Returns the debug name for the function, which is supposed to be used
-// by the debugger and the developer tools. This can thus be different from
-// the name returned by the StackFrame::GetFunctionName() method. For example,
-// in case of WebAssembly, the debug name is WAT-compatible and thus always
-// preceeded by a dollar ('$').
-Local<String> GetFunctionDebugName(Local<StackFrame> frame);
-
 // Returns a debug string representation of the function.
 Local<String> GetFunctionDescription(Local<Function> function);
 

src/inspector/v8-debugger.cc

@@ -1094,8 +1094,7 @@ std::shared_ptr<StackFrame> V8Debugger::symbolize(
   int lineNumber = v8Frame->GetLineNumber() - 1;
   int columnNumber = v8Frame->GetColumn() - 1;
   CachedStackFrameKey key{scriptId, lineNumber, columnNumber};
-  auto functionName =
-      toProtocolString(isolate(), v8::debug::GetFunctionDebugName(v8Frame));
+  auto functionName = toProtocolString(isolate(), v8Frame->GetFunctionName());
   auto it = m_cachedStackFrames.find(key);
   if (it != m_cachedStackFrames.end() && !it->second.expired()) {
     auto stackFrame = it->second.lock();

src/objects/stack-frame-info.h

@@ -50,8 +50,8 @@ class StackFrameInfo
   // Used to signal that the requested field is unknown.
   static constexpr int kUnknown = kNoSourcePosition;
 
-  static int GetLineNumber(Handle<StackFrameInfo> info);
-  static int GetColumnNumber(Handle<StackFrameInfo> info);
+  V8_EXPORT_PRIVATE static int GetLineNumber(Handle<StackFrameInfo> info);
+  V8_EXPORT_PRIVATE static int GetColumnNumber(Handle<StackFrameInfo> info);
 
   static int GetEnclosingLineNumber(Handle<StackFrameInfo> info);
   static int GetEnclosingColumnNumber(Handle<StackFrameInfo> info);
@@ -65,7 +65,8 @@ class StackFrameInfo
   Object GetScriptSourceMappingURL() const;
 
   static Handle<PrimitiveHeapObject> GetEvalOrigin(Handle<StackFrameInfo> info);
-  static Handle<Object> GetFunctionName(Handle<StackFrameInfo> info);
+  V8_EXPORT_PRIVATE static Handle<Object> GetFunctionName(
+      Handle<StackFrameInfo> info);
   static Handle<Object> GetMethodName(Handle<StackFrameInfo> info);
   static Handle<Object> GetTypeName(Handle<StackFrameInfo> info);
 

test/cctest/wasm/test-wasm-stack.cc

@@ -158,11 +158,11 @@ WASM_COMPILED_EXEC_TEST(CollectDetailedWasmStack_ExplicitThrowFromJs) {
   CHECK(returnObjMaybe.is_null());
 
   ExceptionInfo expected_exceptions[] = {
-      {"a", 3, 8},           // -
-      {"js", 4, 2},          // -
-      {"main", 1, 8},        // -
-      {"call_main", 1, 21},  // -
-      {"callFn", 1, 24}      // -
+      {"a", 3, 8},            // -
+      {"js", 4, 2},           // -
+      {"$main", 1, 8},        // -
+      {"$call_main", 1, 21},  // -
+      {"callFn", 1, 24}       // -
   };
   CheckExceptionInfos(isolate, maybe_exc.ToHandleChecked(),
                       expected_exceptions);
@@ -275,9 +275,9 @@ WASM_COMPILED_EXEC_TEST(CollectDetailedWasmStack_WasmError) {
         unreachable_pos + main_offset + kMainLocalsLength + 1;
     const int expected_call_main_pos = call_main_offset + kMainLocalsLength + 1;
     ExceptionInfo expected_exceptions[] = {
-        {"main", 1, expected_main_pos},            // -
-        {"call_main", 1, expected_call_main_pos},  // -
-        {"callFn", 1, 24}                          //-
+        {"$main", 1, expected_main_pos},            // -
+        {"$call_main", 1, expected_call_main_pos},  // -
+        {"callFn", 1, 24}                           //-
     };
     CheckExceptionInfos(isolate, exception, expected_exceptions);
   }

test/cctest/wasm/test-wasm-trap-position.cc

@@ -5,6 +5,7 @@
 #include "include/v8-function.h"
 #include "src/api/api-inl.h"
 #include "src/codegen/assembler-inl.h"
+#include "src/objects/stack-frame-info-inl.h"
 #include "src/trap-handler/trap-handler.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/compiler/value-helper.h"
@@ -40,25 +41,24 @@ struct ExceptionInfo {
 };
 
 template <int N>
-void CheckExceptionInfos(v8::internal::Isolate* i_isolate, Handle<Object> exc,
+void CheckExceptionInfos(v8::internal::Isolate* isolate, Handle<Object> exc,
                          const ExceptionInfo (&excInfos)[N]) {
   // Check that it's indeed an Error object.
   CHECK(exc->IsJSError());
-  v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(i_isolate);
 
   exc->Print();
   // Extract stack frame from the exception.
-  Local<v8::Value> localExc = Utils::ToLocal(exc);
-  v8::Local<v8::StackTrace> stack = v8::Exception::GetStackTrace(localExc);
-  CHECK(!stack.IsEmpty());
-  CHECK_EQ(N, stack->GetFrameCount());
-
-  for (int frameNr = 0; frameNr < N; ++frameNr) {
-    v8::Local<v8::StackFrame> frame = stack->GetFrame(v8_isolate, frameNr);
-    v8::String::Utf8Value funName(v8_isolate, frame->GetFunctionName());
-    CHECK_CSTREQ(excInfos[frameNr].func_name, *funName);
-    CHECK_EQ(excInfos[frameNr].line_nr, frame->GetLineNumber());
-    CHECK_EQ(excInfos[frameNr].column, frame->GetColumn());
+  auto stack = Handle<FixedArray>::cast(JSReceiver::GetDataProperty(
+      Handle<JSObject>::cast(exc), isolate->factory()->stack_trace_symbol()));
+  CHECK_EQ(N, stack->length());
+
+  for (int i = 0; i < N; ++i) {
+    Handle<StackFrameInfo> info(StackFrameInfo::cast(stack->get(i)), isolate);
+    auto func_name = Handle<String>::cast(StackFrameInfo::GetFunctionName(info))
+                         ->ToCString();
+    CHECK_CSTREQ(excInfos[i].func_name, func_name.get());
+    CHECK_EQ(excInfos[i].line_nr, StackFrameInfo::GetLineNumber(info));
+    CHECK_EQ(excInfos[i].column, StackFrameInfo::GetColumnNumber(info));
   }
 }