[NativePDB] Change GetOrCreateFunctionDecl to private and introduce CreateFunctionDecl

[lanza]

Summary

We're removing all clang specific details from PdbAstBuilder in order
to make it an abstract base class and then create subclasses specific
to the language.

GetOrCreateFunctionDecl returns a clang::FunctionDecl. But the only
class that uses the return is PdbAstBuilder itself. So we can simply
create a wrapper with no return that jumps to the actual creation
function in order to remove the clang specific behavior from
PdbAstBuilder.

source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.h

public:
   PdbAstBuilder(ObjectFile &obj, PdbIndex &index);
 
   lldb_private::CompilerDeclContext GetTranslationUnitDecl();
 
   lldb_private::CompilerDecl GetOrCreateDeclForUid(PdbSymUid uid);
   lldb_private::CompilerDeclContext GetOrCreateDeclContextForUid(PdbSymUid uid);
   lldb_private::CompilerDeclContext GetParentDeclContext(PdbSymUid uid);
 
-  clang::FunctionDecl *GetOrCreateFunctionDecl(PdbCompilandSymId func_id);
+  void CreateFunctionDecl(PdbCompilandSymId func_id);
   clang::BlockDecl *GetOrCreateBlockDecl(PdbCompilandSymId block_id);
   clang::VarDecl *GetOrCreateVariableDecl(PdbCompilandSymId scope_id,
                                           PdbCompilandSymId var_id);
   clang::VarDecl *GetOrCreateVariableDecl(PdbGlobalSymId var_id);
   clang::TypedefNameDecl *GetOrCreateTypedefDecl(PdbGlobalSymId id);
   void ParseDeclsForContext(clang::DeclContext &context);
 
   clang::QualType GetBasicType(lldb::BasicType type);
   clang::QualType GetOrCreateType(PdbTypeSymId type);
 
   bool CompleteTagDecl(clang::TagDecl &tag);
   bool CompleteType(clang::QualType qt);
 
   CompilerDecl ToCompilerDecl(clang::Decl &decl);
   CompilerType ToCompilerType(clang::QualType qt);
   CompilerDeclContext ToCompilerDeclContext(clang::DeclContext &context);
   clang::DeclContext *FromCompilerDeclContext(CompilerDeclContext context);
 
   ClangASTContext &clang() { return m_clang; }
   ClangASTImporter &importer() { return m_importer; }
 
   void Dump(Stream &stream);
 
 private:
+  clang::FunctionDecl *GetOrCreateFunctionDecl(PdbCompilandSymId func_id);
+
   clang::Decl *TryGetDecl(PdbSymUid uid) const;
 
   using TypeIndex = llvm::codeview::TypeIndex;
 
   clang::QualType
   CreatePointerType(const llvm::codeview::PointerRecord &pointer);
   clang::QualType
   CreateModifierType(const llvm::codeview::ModifierRecord &modifier);

source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp

if (IsTagRecord(type, m_index.tpi())) {
 
     DeclStatus &status = m_decl_to_status[tag];
     status.uid = uid;
     status.resolved = false;
   }
   return qt;
 }
 
+void PdbAstBuilder::CreateFunctionDecl(PdbCompilandSymId func_id) {
+  GetOrCreateFunctionDecl(func_id);
+}
+
 clang::FunctionDecl *
 PdbAstBuilder::GetOrCreateFunctionDecl(PdbCompilandSymId func_id) {
   if (clang::Decl *decl = TryGetDecl(func_id))
     return llvm::dyn_cast<clang::FunctionDecl>(decl);
 
   lldb_private::CompilerDeclContext decl_ctx =
       GetParentDeclContext(PdbSymUid(func_id));
   auto parent =

source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

lldb::FunctionSP SymbolFileNativePDB::CreateFunction(PdbCompilandSymId func_id,
   PdbTypeSymId sig_id(proc.FunctionType, false);
   Mangled mangled(proc.Name);
   FunctionSP func_sp = std::make_shared<Function>(
       &comp_unit, toOpaqueUid(func_id), toOpaqueUid(sig_id), mangled,
       func_type.get(), func_range);
 
   comp_unit.AddFunction(func_sp);
 
-  m_ast->GetOrCreateFunctionDecl(func_id);
+  m_ast->CreateFunctionDecl(func_id);
 
   return func_sp;
 }
 
 CompUnitSP
 SymbolFileNativePDB::CreateCompileUnit(const CompilandIndexItem &cci) {
   lldb::LanguageType lang =
       cci.m_compile_opts ? TranslateLanguage(cci.m_compile_opts->getLanguage())