[torque] Print bitfield source positions

Change-Id: Ic394381f5159211a437e8ee30a474ed974b7f930
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3832374
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82477}

src/torque/implementation-visitor.cc

@@ -3884,7 +3884,7 @@ void ImplementationVisitor::GenerateBitFields(
 
     for (const auto& type : TypeOracle::GetBitFieldStructTypes()) {
       bool all_single_bits = true;  // Track whether every field is one bit.
-
+      header << "// " << type->GetPosition() << "\n";
       header << "#define DEFINE_TORQUE_GENERATED_"
              << CapifyStringWithUnderscores(type->name()) << "() \\\n";
       std::string type_name = type->GetConstexprGeneratedTypeName();

src/torque/types.h

@@ -521,6 +521,8 @@ class V8_EXPORT_PRIVATE BitFieldStructType final : public Type {
 
   const BitField& LookupField(const std::string& name) const;
 
+  const SourcePosition GetPosition() const { return decl_->pos; }
+
  private:
   friend class TypeOracle;
   BitFieldStructType(Namespace* nspace, const Type* parent,