[DWARF parser] Produce correct template parameter packs

[spyffe]

Summary

Templates can end in parameter packs, like this

template <class T...> struct MyStruct { /*...*/ };

LLDB does not currently support these parameter packs; it does not emit them into the template argument list at all. This causes problems when you specialize, e.g.:

template <> struct MyStruct<int> { /*...*/ };
template <> struct MyStruct<int, int> : MyStruct<int> { /*...*/ };

LLDB generates two template specializations, each with no template arguments, and then when they are imported by the ASTImporter into a parser's AST context we get a single specialization that inherits from itself, causing Clang's record layout mechanism to smash its stack.

This patch fixes the problem for classes and adds tests. The tests for functions fail because Clang's ASTImporter can't import them at the moment, so I've xfailed that test.

[clayborg]

Very nice

lldb/trunk/include/lldb/Symbol/ClangASTContext.h

CompilerType CreateRecordType(clang::DeclContext *decl_ctx,
                                 int kind, lldb::LanguageType language,
                                 ClangASTMetadata *metadata = nullptr);
 
   class TemplateParameterInfos {
   public:
     bool IsValid() const {
       if (args.empty())
         return false;
-      return args.size() == names.size();
-    }
-
-    size_t GetSize() const {
-      if (IsValid())
-        return args.size();
-      return 0;
+      return args.size() == names.size() &&
+        ((bool)pack_name == (bool)packed_args) &&
+        (!packed_args || !packed_args->packed_args);
     }
 
     llvm::SmallVector<const char *, 2> names;
     llvm::SmallVector<clang::TemplateArgument, 2> args;
+    
+    const char * pack_name = nullptr;
+    std::unique_ptr<TemplateParameterInfos> packed_args;
   };
 
   clang::FunctionTemplateDecl *
   CreateFunctionTemplateDecl(clang::DeclContext *decl_ctx,
                              clang::FunctionDecl *func_decl, const char *name,
                              const TemplateParameterInfos &infos);
 
   void CreateFunctionTemplateSpecializationInfo(

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/class-template-parameter-pack/Makefile

+LEVEL = ../../../make
+CXX_SOURCES := main.cpp
+include $(LEVEL)/Makefile.rules

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/class-template-parameter-pack/TestClassTemplateParameterPack.py

+from lldbsuite.test import lldbinline
+from lldbsuite.test import decorators
+
+lldbinline.MakeInlineTest(
+    __file__, globals(), [
+        decorators.expectedFailureAll(
+            oslist=["windows"], bugnumber="llvm.org/pr24764")])

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/class-template-parameter-pack/main.cpp

+//===-- main.cpp ------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LIDENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+template <class T, int... Args> struct C {
+  T member;
+  bool isSixteenThirtyTwo() { return false; }
+};
+
+template <> struct C<int, 16> {
+  int member;
+  bool isSixteenThirtyTwo() { return false; }
+};
+
+template <> struct C<int, 16, 32> : C<int, 16> {
+  bool isSixteenThirtyTwo() { return true; }
+};
+
+template <class T, typename... Args> struct D {
+  T member;
+  bool isIntBool() { return false; }
+};
+
+template <> struct D<int, int> {
+  int member;
+  bool isIntBool() { return false; }
+};
+
+template <> struct D<int, int, bool> : D<int, int> {
+  bool isIntBool() { return true; }
+};
+
+int main (int argc, char const *argv[])
+{
+    C<int,16,32> myC;
+    C<int,16> myLesserC;
+    myC.member = 64;
+    (void)C<int,16,32>().isSixteenThirtyTwo();
+    (void)C<int,16>().isSixteenThirtyTwo();
+    (void)(myC.member != 64);   //% self.expect("expression -- myC", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["64"])
+                                //% self.expect("expression -- C<int, 16>().isSixteenThirtyTwo()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["false"])
+                                //% self.expect("expression -- C<int, 16, 32>().isSixteenThirtyTwo()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["true"])
+                                //% self.expect("expression -- myLesserC.isSixteenThirtyTwo()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["false"])
+                                //% self.expect("expression -- myC.isSixteenThirtyTwo()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["true"])
+   
+    D<int,int,bool> myD;
+    D<int,int> myLesserD;
+    myD.member = 64;
+    (void)D<int,int,bool>().isIntBool();
+    (void)D<int,int>().isIntBool();
+    return myD.member != 64;  //% self.expect("expression -- myD", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["64"])
+                                //% self.expect("expression -- D<int, int>().isIntBool()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["false"])
+                                //% self.expect("expression -- D<int, int, bool>().isIntBool()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["true"])
+                                //% self.expect("expression -- myLesserD.isIntBool()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["false"])
+                                //% self.expect("expression -- myD.isIntBool()", DATA_TYPES_DISPLAYED_CORRECTLY, substrs = ["true"])
+}

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/function-template-parameter-pack/Makefile

+LEVEL = ../../../make
+CXX_SOURCES := main.cpp
+include $(LEVEL)/Makefile.rules

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/function-template-parameter-pack/TestFunctionTemplateParameterPack.py

+from lldbsuite.test import lldbinline
+from lldbsuite.test import decorators
+
+lldbinline.MakeInlineTest(
+    __file__, globals(), [
+        decorators.expectedFailureAll(bugnumber="rdar://problem/32096064")])

lldb/trunk/packages/Python/lldbsuite/test/lang/cpp/function-template-parameter-pack/main.cpp

+//===-- main.cpp ------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LIDENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+template <class T> int staticSizeof() {
+  return sizeof(T);
+}
+
+template <class T1, class T2, class... Ts> int staticSizeof() {
+  return staticSizeof<T2, Ts...>() + sizeof(T1);
+}
+
+int main (int argc, char const *argv[])
+{
+  int sz = staticSizeof<long, int, char>();
+  return staticSizeof<long, int, char>() != sz; //% self.expect("expression -- sz == staticSizeof<long, int, char>()", "staticSizeof<long, int, char> worked", substrs = ["true"])
+                                  //% self.expect("expression -- sz == staticSizeof<long, int>() + sizeof(char)", "staticSizeof<long, int> worked", substrs = ["true"])
+                                  //% self.expect("expression -- sz == staticSizeof<long>() + sizeof(int) + sizeof(char)", "staticSizeof<long> worked", substrs = ["true"])
+}

lldb/trunk/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp

if (!extern_c) {
       TypeSystem *type_system = function->GetDeclContext().GetTypeSystem();
       if (ClangASTContext *src_ast =
               llvm::dyn_cast<ClangASTContext>(type_system)) {
         clang::DeclContext *src_decl_context =
             (clang::DeclContext *)function->GetDeclContext()
                 .GetOpaqueDeclContext();
         clang::FunctionDecl *src_function_decl =
             llvm::dyn_cast_or_null<clang::FunctionDecl>(src_decl_context);
+        if (src_function_decl &&
+            src_function_decl->getTemplateSpecializationInfo()) {
+          clang::FunctionTemplateDecl *function_template =
+              src_function_decl->getTemplateSpecializationInfo()->getTemplate();
+          clang::FunctionTemplateDecl *copied_function_template =
+              llvm::dyn_cast_or_null<clang::FunctionTemplateDecl>(
+                 m_ast_importer_sp->CopyDecl(m_ast_context,
+                                             src_ast->getASTContext(),
+                                             function_template));
+          if (copied_function_template) {
+            if (log) {
+              ASTDumper ast_dumper((clang::Decl *)copied_function_template);
+              
+              StreamString ss;
+              
+              function->DumpSymbolContext(&ss);
+              
+              log->Printf("  CEDM::FEVD[%u] Imported decl for function template"
+                          " %s (description %s), returned %s",
+                          current_id,
+                          copied_function_template->getNameAsString().c_str(),
+                          ss.GetData(), ast_dumper.GetCString());
+            }
             
-        if (src_function_decl) {
+            context.AddNamedDecl(copied_function_template);
+          }
+        } else if (src_function_decl) {
           if (clang::FunctionDecl *copied_function_decl =
                   llvm::dyn_cast_or_null<clang::FunctionDecl>(
                       m_ast_importer_sp->CopyDecl(m_ast_context,
                                                   src_ast->getASTContext(),
                                                   src_function_decl))) {
             if (log) {
               ASTDumper ast_dumper((clang::Decl *)copied_function_decl);
 

lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

 
             if (!function_decl) {
               // We just have a function that isn't part of a class
               function_decl = m_ast.CreateFunctionDeclaration(
                   ignore_containing_context ? m_ast.GetTranslationUnitDecl()
                                             : containing_decl_ctx,
                   type_name_cstr, clang_type, storage, is_inline);
 
-              //                            if (template_param_infos.GetSize() >
-              //                            0)
-              //                            {
-              //                                clang::FunctionTemplateDecl
-              //                                *func_template_decl =
-              //                                CreateFunctionTemplateDecl
-              //                                (containing_decl_ctx,
-              //                                                                                                              function_decl,
-              //                                                                                                              type_name_cstr,
-              //                                                                                                              template_param_infos);
-              //
-              //                                CreateFunctionTemplateSpecializationInfo
-              //                                (function_decl,
-              //                                                                          func_template_decl,
-              //                                                                          template_param_infos);
-              //                            }
-              // Add the decl to our DIE to decl context map
+              if (has_template_params) {
+                ClangASTContext::TemplateParameterInfos template_param_infos;
+                ParseTemplateParameterInfos(die, template_param_infos);
+                clang::FunctionTemplateDecl *func_template_decl =
+                    m_ast.CreateFunctionTemplateDecl(
+                        containing_decl_ctx, function_decl, type_name_cstr,
+                        template_param_infos);
+                m_ast.CreateFunctionTemplateSpecializationInfo(
+                    function_decl, func_template_decl, template_param_infos);
+              }
               
               lldbassert(function_decl);
 
               if (function_decl) {
                 LinkDeclContextToDIE(function_decl, die);
 
                 if (!function_param_decls.empty())
                   m_ast.SetFunctionParameters(function_decl,
                                               &function_param_decls.front(),

 };
 
 bool DWARFASTParserClang::ParseTemplateDIE(
     const DWARFDIE &die,
     ClangASTContext::TemplateParameterInfos &template_param_infos) {
   const dw_tag_t tag = die.Tag();
 
   switch (tag) {
+  case DW_TAG_GNU_template_parameter_pack: {
+    template_param_infos.packed_args.reset(
+      new ClangASTContext::TemplateParameterInfos);
+    for (DWARFDIE child_die = die.GetFirstChild(); child_die.IsValid();
+         child_die = child_die.GetSibling()) {
+      if (!ParseTemplateDIE(child_die, *template_param_infos.packed_args))
+        return false;
+    }
+    if (const char *name = die.GetName()) {
+      template_param_infos.pack_name = name;
+    }
+    return true;
+  }
   case DW_TAG_template_type_parameter:
   case DW_TAG_template_value_parameter: {
     DWARFAttributes attributes;
     const size_t num_attributes = die.GetAttributes(attributes);
     const char *name = nullptr;
     CompilerType clang_type;
     uint64_t uval64 = 0;
     bool uval64_valid = false;
bool DWARFASTParserClang::ParseTemplateParameterInfos(
   Args template_parameter_names;
   for (DWARFDIE die = parent_die.GetFirstChild(); die.IsValid();
        die = die.GetSibling()) {
     const dw_tag_t tag = die.Tag();
 
     switch (tag) {
     case DW_TAG_template_type_parameter:
     case DW_TAG_template_value_parameter:
+    case DW_TAG_GNU_template_parameter_pack:
       ParseTemplateDIE(die, template_param_infos);
       break;
 
     default:
       break;
     }
   }
   if (template_param_infos.args.empty())
for (DWARFDIE die = parent_die.GetFirstChild(); die.IsValid();
     } break;
 
     case DW_TAG_unspecified_parameters:
       is_variadic = true;
       break;
 
     case DW_TAG_template_type_parameter:
     case DW_TAG_template_value_parameter:
+    case DW_TAG_GNU_template_parameter_pack:
       // The one caller of this was never using the template_param_infos,
       // and the local variable was taking up a large amount of stack space
       // in SymbolFileDWARF::ParseType() so this was removed. If we ever need
       // the template params back, we can add them back.
       // ParseTemplateDIE (dwarf_cu, die, template_param_infos);
       has_template_params = true;
       break;
 

lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp

case DW_TAG_packed_type:
       break;
     case DW_TAG_subprogram:
       match_addr_range = true;
       break;
     case DW_TAG_template_type_parameter:
       break;
     case DW_TAG_template_value_parameter:
       break;
+    case DW_TAG_GNU_template_parameter_pack:
+      break;
     case DW_TAG_thrown_type:
       break;
     case DW_TAG_try_block:
       match_addr_range = true;
       break;
     case DW_TAG_variant_part:
       break;
     case DW_TAG_variable:

lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFDefines.cpp

DW_TAG_CategoryEnum get_tag_category(uint16_t tag) {
   case DW_TAG_packed_type:
     return TagCategoryType;
   case DW_TAG_subprogram:
     return TagCategoryProgram;
   case DW_TAG_template_type_parameter:
     return TagCategoryType;
   case DW_TAG_template_value_parameter:
     return TagCategoryType;
+  case DW_TAG_GNU_template_parameter_pack:
+    return TagCategoryType;
   case DW_TAG_thrown_type:
     return TagCategoryType;
   case DW_TAG_try_block:
     return TagCategoryProgram;
   case DW_TAG_variant_part:
     return TagCategoryType;
   case DW_TAG_variable:
     return TagCategoryVariable;

lldb/trunk/source/Symbol/ClangASTContext.cpp

if (decl) {
     if (decl_ctx)
       decl_ctx->addDecl(decl);
 
     return CompilerType(ast, ast->getTagDeclType(decl));
   }
   return CompilerType();
 }
 
+namespace {
+  bool IsValueParam(const clang::TemplateArgument &argument) {
+    return argument.getKind() == TemplateArgument::Integral;
+  }
+}
+
 static TemplateParameterList *CreateTemplateParameterList(
     ASTContext *ast,
     const ClangASTContext::TemplateParameterInfos &template_param_infos,
     llvm::SmallVector<NamedDecl *, 8> &template_param_decls) {
   const bool parameter_pack = false;
   const bool is_typename = false;
   const unsigned depth = 0;
-  const size_t num_template_params = template_param_infos.GetSize();
+  const size_t num_template_params = template_param_infos.args.size();
+  DeclContext *const decl_context =
+      ast->getTranslationUnitDecl(); // Is this the right decl context?,
   for (size_t i = 0; i < num_template_params; ++i) {
     const char *name = template_param_infos.names[i];
 
     IdentifierInfo *identifier_info = nullptr;
     if (name && name[0])
       identifier_info = &ast->Idents.get(name);
-    if (template_param_infos.args[i].getKind() == TemplateArgument::Integral) {
+    if (IsValueParam(template_param_infos.args[i])) {
       template_param_decls.push_back(NonTypeTemplateParmDecl::Create(
-          *ast,
-          ast->getTranslationUnitDecl(), // Is this the right decl context?,
-                                         // SourceLocation StartLoc,
+          *ast, decl_context,
           SourceLocation(), SourceLocation(), depth, i, identifier_info,
           template_param_infos.args[i].getIntegralType(), parameter_pack,
           nullptr));
 
     } else {
       template_param_decls.push_back(TemplateTypeParmDecl::Create(
-          *ast,
-          ast->getTranslationUnitDecl(), // Is this the right decl context?
+          *ast, decl_context,
           SourceLocation(), SourceLocation(), depth, i, identifier_info,
           is_typename, parameter_pack));
     }
   }
   
+  if (template_param_infos.packed_args &&
+      template_param_infos.packed_args->args.size()) {
+    IdentifierInfo *identifier_info = nullptr;
+    if (template_param_infos.pack_name && template_param_infos.pack_name[0])
+      identifier_info = &ast->Idents.get(template_param_infos.pack_name);
+    const bool parameter_pack_true = true;
+    if (IsValueParam(template_param_infos.packed_args->args[0])) {
+      template_param_decls.push_back(NonTypeTemplateParmDecl::Create(
+          *ast, decl_context,
+          SourceLocation(), SourceLocation(), depth, num_template_params,
+          identifier_info,
+          template_param_infos.packed_args->args[0].getIntegralType(),
+          parameter_pack_true, nullptr));
+    } else {
+      template_param_decls.push_back(TemplateTypeParmDecl::Create(
+          *ast, decl_context,
+          SourceLocation(), SourceLocation(), depth, num_template_params,
+          identifier_info,
+          is_typename, parameter_pack_true));
+    }
+  }
   clang::Expr *const requires_clause = nullptr; // TODO: Concepts
   TemplateParameterList *template_param_list = TemplateParameterList::Create(
       *ast, SourceLocation(), SourceLocation(), template_param_decls,
       SourceLocation(), requires_clause);
   return template_param_list;
 }
 
 clang::FunctionTemplateDecl *ClangASTContext::CreateFunctionTemplateDecl(
#endif
   return class_template_decl;
 }
 
 ClassTemplateSpecializationDecl *
 ClangASTContext::CreateClassTemplateSpecializationDecl(
     DeclContext *decl_ctx, ClassTemplateDecl *class_template_decl, int kind,
     const TemplateParameterInfos &template_param_infos) {
   ASTContext *ast = getASTContext();
+  llvm::SmallVector<clang::TemplateArgument, 2> args(
+      template_param_infos.args.size() +
+      (template_param_infos.packed_args ? 1 : 0));
+  std::copy(template_param_infos.args.begin(), template_param_infos.args.end(),
+            args.begin());
+  if (template_param_infos.packed_args) {
+    args[args.size() - 1] = TemplateArgument::CreatePackCopy(
+        *ast, template_param_infos.packed_args->args);
+  }
   ClassTemplateSpecializationDecl *class_template_specialization_decl =
       ClassTemplateSpecializationDecl::Create(
           *ast, (TagDecl::TagKind)kind, decl_ctx, SourceLocation(),
-          SourceLocation(), class_template_decl, template_param_infos.args,
+          SourceLocation(), class_template_decl, args,
           nullptr);
 
   class_template_specialization_decl->setSpecializationKind(
       TSK_ExplicitSpecialization);
 
   return class_template_specialization_decl;
 }