Allow BytecodeArray::Disassemble to be called by a background thread

BytecodeArray::Disassemble fails a SLOW_DCHECK when invoking from
a background thread, due to the little hack to recover the handle
inside the function.

This CL changes the method to static with a handle as input.
The old method calls the static one, since it is allowed to be
called by the main thread.

Change-Id: I3546f0d2b160d15386da0980efc539693672c230
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3879498
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83063}

src/maglev/maglev-compiler.cc

@@ -547,7 +547,7 @@ void MaglevCompiler::Compile(LocalIsolate* local_isolate,
         compilation_info->toplevel_compilation_unit();
     std::cout << "Compiling " << Brief(*top_level_unit->function().object())
               << " with Maglev\n";
-    top_level_unit->bytecode().object()->Disassemble(std::cout);
+    BytecodeArray::Disassemble(top_level_unit->bytecode().object(), std::cout);
     top_level_unit->feedback().object()->Print(std::cout);
   }
 

src/objects/code.cc

@@ -752,19 +752,26 @@ void BytecodeArray::PrintJson(std::ostream& os) {
 
 void BytecodeArray::Disassemble(std::ostream& os) {
   DisallowGarbageCollection no_gc;
-
-  os << "Parameter count " << parameter_count() << "\n";
-  os << "Register count " << register_count() << "\n";
-  os << "Frame size " << frame_size() << "\n";
-  os << "Bytecode age: " << bytecode_age() << "\n";
-
-  Address base_address = GetFirstBytecodeAddress();
-  SourcePositionTableIterator source_positions(SourcePositionTable());
-
   // Storage for backing the handle passed to the iterator. This handle won't be
   // updated by the gc, but that's ok because we've disallowed GCs anyway.
   BytecodeArray handle_storage = *this;
   Handle<BytecodeArray> handle(reinterpret_cast<Address*>(&handle_storage));
+  Disassemble(handle, os);
+}
+
+// static
+void BytecodeArray::Disassemble(Handle<BytecodeArray> handle,
+                                std::ostream& os) {
+  DisallowGarbageCollection no_gc;
+
+  os << "Parameter count " << handle->parameter_count() << "\n";
+  os << "Register count " << handle->register_count() << "\n";
+  os << "Frame size " << handle->frame_size() << "\n";
+  os << "Bytecode age: " << handle->bytecode_age() << "\n";
+
+  Address base_address = handle->GetFirstBytecodeAddress();
+  SourcePositionTableIterator source_positions(handle->SourcePositionTable());
+
   interpreter::BytecodeArrayIterator iterator(handle);
   while (!iterator.done()) {
     if (!source_positions.done() &&
@@ -803,22 +810,22 @@ void BytecodeArray::Disassemble(std::ostream& os) {
     iterator.Advance();
   }
 
-  os << "Constant pool (size = " << constant_pool().length() << ")\n";
+  os << "Constant pool (size = " << handle->constant_pool().length() << ")\n";
 #ifdef OBJECT_PRINT
-  if (constant_pool().length() > 0) {
-    constant_pool().Print(os);
+  if (handle->constant_pool().length() > 0) {
+    handle->constant_pool().Print(os);
   }
 #endif
 
-  os << "Handler Table (size = " << handler_table().length() << ")\n";
+  os << "Handler Table (size = " << handle->handler_table().length() << ")\n";
 #ifdef ENABLE_DISASSEMBLER
-  if (handler_table().length() > 0) {
-    HandlerTable table(*this);
+  if (handle->handler_table().length() > 0) {
+    HandlerTable table(*handle);
     table.HandlerTableRangePrint(os);
   }
 #endif
 
-  ByteArray source_position_table = SourcePositionTable();
+  ByteArray source_position_table = handle->SourcePositionTable();
   os << "Source Position Table (size = " << source_position_table.length()
      << ")\n";
 #ifdef OBJECT_PRINT

src/objects/code.h

@@ -1281,6 +1281,9 @@ class BytecodeArray
   V8_EXPORT_PRIVATE void PrintJson(std::ostream& os);
   V8_EXPORT_PRIVATE void Disassemble(std::ostream& os);
 
+  V8_EXPORT_PRIVATE static void Disassemble(Handle<BytecodeArray> handle,
+                                            std::ostream& os);
+
   void CopyBytecodesTo(BytecodeArray to);
 
   // Bytecode aging