[Clang] Add BuiltinTemplates.td to generate code for builtin templates (#123736)

This makes it significantly easier to add new builtin templates, since
you only have to modify two places instead of a dozen or so.

The `BuiltinTemplates.td` could also be extended to generate
documentation from it in the future.

7 files changed, 32 insertions, 198 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 4a79131..fce1c34 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -1198,28 +1198,14 @@ ASTContext::buildBuiltinTemplateDecl(BuiltinTemplateKind BTK,
   return BuiltinTemplate;
 }
 
-BuiltinTemplateDecl *
-ASTContext::getMakeIntegerSeqDecl() const {
-  if (!MakeIntegerSeqDecl)
-    MakeIntegerSeqDecl = buildBuiltinTemplateDecl(BTK__make_integer_seq,
-                                                  getMakeIntegerSeqName());
-  return MakeIntegerSeqDecl;
-}
-
-BuiltinTemplateDecl *
-ASTContext::getTypePackElementDecl() const {
-  if (!TypePackElementDecl)
-    TypePackElementDecl = buildBuiltinTemplateDecl(BTK__type_pack_element,
-                                                   getTypePackElementName());
-  return TypePackElementDecl;
-}
-
-BuiltinTemplateDecl *ASTContext::getBuiltinCommonTypeDecl() const {
-  if (!BuiltinCommonTypeDecl)
-    BuiltinCommonTypeDecl = buildBuiltinTemplateDecl(
-        BTK__builtin_common_type, getBuiltinCommonTypeName());
-  return BuiltinCommonTypeDecl;
-}
+#define BuiltinTemplate(BTName)                                                \
+  BuiltinTemplateDecl *ASTContext::get##BTName##Decl() const {                 \
+    if (!Decl##BTName)                                                         \
+      Decl##BTName =                                                           \
+          buildBuiltinTemplateDecl(BTK##BTName, get##BTName##Name());          \
+    return Decl##BTName;                                                       \
+  }
+#include "clang/Basic/BuiltinTemplates.inc"
 
 RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
                                             RecordDecl::TagKind TK) const {
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 43da76e..8218048 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -5465,15 +5465,11 @@ ExpectedDecl ASTNodeImporter::VisitUnresolvedUsingTypenameDecl(
 ExpectedDecl ASTNodeImporter::VisitBuiltinTemplateDecl(BuiltinTemplateDecl *D) {
   Decl* ToD = nullptr;
   switch (D->getBuiltinTemplateKind()) {
-  case BuiltinTemplateKind::BTK__make_integer_seq:
-    ToD = Importer.getToContext().getMakeIntegerSeqDecl();
-    break;
-  case BuiltinTemplateKind::BTK__type_pack_element:
-    ToD = Importer.getToContext().getTypePackElementDecl();
-    break;
-  case BuiltinTemplateKind::BTK__builtin_common_type:
-    ToD = Importer.getToContext().getBuiltinCommonTypeDecl();
+#define BuiltinTemplate(BTName)                                                \
+  case BuiltinTemplateKind::BTK##BTName:                                       \
+    ToD = Importer.getToContext().get##BTName##Decl();                         \
     break;
+#include "clang/Basic/BuiltinTemplates.inc"
   }
   assert(ToD && "BuiltinTemplateDecl of unsupported kind!");
   Importer.MapImported(D, ToD);
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 63caf04..b8fe19c 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -1581,140 +1581,11 @@ SourceRange VarTemplatePartialSpecializationDecl::getSourceRange() const {
   return Range;
 }
 
-static TemplateParameterList *
-createMakeIntegerSeqParameterList(const ASTContext &C, DeclContext *DC) {
-  // typename T
-  auto *T = TemplateTypeParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/1, /*Position=*/0,
-      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/false,
-      /*HasTypeConstraint=*/false);
-  T->setImplicit(true);
-
-  // T ...Ints
-  TypeSourceInfo *TI =
-      C.getTrivialTypeSourceInfo(QualType(T->getTypeForDecl(), 0));
-  auto *N = NonTypeTemplateParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
-      /*Id=*/nullptr, TI->getType(), /*ParameterPack=*/true, TI);
-  N->setImplicit(true);
-
-  // <typename T, T ...Ints>
-  NamedDecl *P[2] = {T, N};
-  auto *TPL = TemplateParameterList::Create(
-      C, SourceLocation(), SourceLocation(), P, SourceLocation(), nullptr);
-
-  // template <typename T, ...Ints> class IntSeq
-  auto *TemplateTemplateParm = TemplateTemplateParmDecl::Create(
-      C, DC, SourceLocation(), /*Depth=*/0, /*Position=*/0,
-      /*ParameterPack=*/false, /*Id=*/nullptr, /*Typename=*/false, TPL);
-  TemplateTemplateParm->setImplicit(true);
-
-  // typename T
-  auto *TemplateTypeParm = TemplateTypeParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
-      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/false,
-      /*HasTypeConstraint=*/false);
-  TemplateTypeParm->setImplicit(true);
-
-  // T N
-  TypeSourceInfo *TInfo = C.getTrivialTypeSourceInfo(
-      QualType(TemplateTypeParm->getTypeForDecl(), 0));
-  auto *NonTypeTemplateParm = NonTypeTemplateParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/2,
-      /*Id=*/nullptr, TInfo->getType(), /*ParameterPack=*/false, TInfo);
-  NamedDecl *Params[] = {TemplateTemplateParm, TemplateTypeParm,
-                         NonTypeTemplateParm};
-
-  // template <template <typename T, T ...Ints> class IntSeq, typename T, T N>
-  return TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
-                                       Params, SourceLocation(), nullptr);
-}
-
-static TemplateParameterList *
-createTypePackElementParameterList(const ASTContext &C, DeclContext *DC) {
-  // std::size_t Index
-  TypeSourceInfo *TInfo = C.getTrivialTypeSourceInfo(C.getSizeType());
-  auto *Index = NonTypeTemplateParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/0,
-      /*Id=*/nullptr, TInfo->getType(), /*ParameterPack=*/false, TInfo);
-
-  // typename ...T
-  auto *Ts = TemplateTypeParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
-      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/true,
-      /*HasTypeConstraint=*/false);
-  Ts->setImplicit(true);
-
-  // template <std::size_t Index, typename ...T>
-  NamedDecl *Params[] = {Index, Ts};
-  return TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
-                                       llvm::ArrayRef(Params), SourceLocation(),
-                                       nullptr);
-}
-
-static TemplateParameterList *createBuiltinCommonTypeList(const ASTContext &C,
-                                                          DeclContext *DC) {
-  // class... Args
-  auto *Args =
-      TemplateTypeParmDecl::Create(C, DC, SourceLocation(), SourceLocation(),
-                                   /*Depth=*/1, /*Position=*/0, /*Id=*/nullptr,
-                                   /*Typename=*/false, /*ParameterPack=*/true);
-
-  // <class... Args>
-  auto *BaseTemplateList = TemplateParameterList::Create(
-      C, SourceLocation(), SourceLocation(), Args, SourceLocation(), nullptr);
-
-  // template <class... Args> class BaseTemplate
-  auto *BaseTemplate = TemplateTemplateParmDecl::Create(
-      C, DC, SourceLocation(), /*Depth=*/0, /*Position=*/0,
-      /*ParameterPack=*/false, /*Id=*/nullptr,
-      /*Typename=*/false, BaseTemplateList);
-
-  // class TypeMember
-  auto *TypeMember =
-      TemplateTypeParmDecl::Create(C, DC, SourceLocation(), SourceLocation(),
-                                   /*Depth=*/1, /*Position=*/0, /*Id=*/nullptr,
-                                   /*Typename=*/false, /*ParameterPack=*/false);
-
-  // <class TypeMember>
-  auto *HasTypeMemberList =
-      TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
-                                    TypeMember, SourceLocation(), nullptr);
-
-  // template <class TypeMember> class HasTypeMember
-  auto *HasTypeMember = TemplateTemplateParmDecl::Create(
-      C, DC, SourceLocation(), /*Depth=*/0, /*Position=*/1,
-      /*ParameterPack=*/false, /*Id=*/nullptr,
-      /*Typename=*/false, HasTypeMemberList);
-
-  // class HasNoTypeMember
-  auto *HasNoTypeMember = TemplateTypeParmDecl::Create(
-      C, DC, {}, {}, /*Depth=*/0, /*Position=*/2, /*Id=*/nullptr,
-      /*Typename=*/false, /*ParameterPack=*/false);
-
-  // class... Ts
-  auto *Ts = TemplateTypeParmDecl::Create(
-      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/3,
-      /*Id=*/nullptr, /*Typename=*/false, /*ParameterPack=*/true);
-
-  // template <template <class... Args> class BaseTemplate,
-  //   template <class TypeMember> class HasTypeMember, class HasNoTypeMember,
-  //   class... Ts>
-  return TemplateParameterList::Create(
-      C, SourceLocation(), SourceLocation(),
-      {BaseTemplate, HasTypeMember, HasNoTypeMember, Ts}, SourceLocation(),
-      nullptr);
-}
-
 static TemplateParameterList *createBuiltinTemplateParameterList(
     const ASTContext &C, DeclContext *DC, BuiltinTemplateKind BTK) {
   switch (BTK) {
-  case BTK__make_integer_seq:
-    return createMakeIntegerSeqParameterList(C, DC);
-  case BTK__type_pack_element:
-    return createTypePackElementParameterList(C, DC);
-  case BTK__builtin_common_type:
-    return createBuiltinCommonTypeList(C, DC);
+#define CREATE_BUILTIN_TEMPLATE_PARAMETER_LIST
+#include "clang/Basic/BuiltinTemplates.inc"
   }
 
   llvm_unreachable("unhandled BuiltinTemplateKind!");
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 944966a..8e35d56 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1831,10 +1831,9 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
             return true;
           } else {
             return llvm::StringSwitch<bool>(II->getName())
-                // Report builtin templates as being builtins.
-                .Case("__make_integer_seq", getLangOpts().CPlusPlus)
-                .Case("__type_pack_element", getLangOpts().CPlusPlus)
-                .Case("__builtin_common_type", getLangOpts().CPlusPlus)
+        // Report builtin templates as being builtins.
+#define BuiltinTemplate(BTName) .Case(#BTName, getLangOpts().CPlusPlus)
+#include "clang/Basic/BuiltinTemplates.inc"
                 // Likewise for some builtin preprocessor macros.
                 // FIXME: This is inconsistent; we usually suggest detecting
                 // builtin macros via #ifdef. Don't add more cases here.
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 0f5b742..aecf8ed 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -924,18 +924,12 @@ bool Sema::LookupBuiltin(LookupResult &R) {
     IdentifierInfo *II = R.getLookupName().getAsIdentifierInfo();
     if (II) {
       if (getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName) {
-        if (II == getASTContext().getMakeIntegerSeqName()) {
-          R.addDecl(getASTContext().getMakeIntegerSeqDecl());
-          return true;
-        }
-        if (II == getASTContext().getTypePackElementName()) {
-          R.addDecl(getASTContext().getTypePackElementDecl());
-          return true;
-        }
-        if (II == getASTContext().getBuiltinCommonTypeName()) {
-          R.addDecl(getASTContext().getBuiltinCommonTypeDecl());
-          return true;
-        }
+#define BuiltinTemplate(BIName)                                                \
+  if (II == getASTContext().get##BIName##Name()) {                             \
+    R.addDecl(getASTContext().get##BIName##Decl());                            \
+    return true;                                                               \
+  }
+#include "clang/Basic/BuiltinTemplates.inc"
       }
 
       // Check if this is an OpenCL Builtin, and if so, insert its overloads.
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 4a40df6..294e8e0 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -8114,12 +8114,6 @@ Decl *ASTReader::getPredefinedDecl(PredefinedDeclIDs ID) {
     NewLoaded = Context.getExternCContextDecl();
     break;
 
-  case PREDEF_DECL_MAKE_INTEGER_SEQ_ID:
-    if (Context.MakeIntegerSeqDecl)
-      return Context.MakeIntegerSeqDecl;
-    NewLoaded = Context.getMakeIntegerSeqDecl();
-    break;
-
   case PREDEF_DECL_CF_CONSTANT_STRING_ID:
     if (Context.CFConstantStringTypeDecl)
       return Context.CFConstantStringTypeDecl;
@@ -8132,17 +8126,13 @@ Decl *ASTReader::getPredefinedDecl(PredefinedDeclIDs ID) {
     NewLoaded = Context.getCFConstantStringTagDecl();
     break;
 
-  case PREDEF_DECL_TYPE_PACK_ELEMENT_ID:
-    if (Context.TypePackElementDecl)
-      return Context.TypePackElementDecl;
-    NewLoaded = Context.getTypePackElementDecl();
-    break;
-
-  case PREDEF_DECL_COMMON_TYPE_ID:
-    if (Context.BuiltinCommonTypeDecl)
-      return Context.BuiltinCommonTypeDecl;
-    NewLoaded = Context.getBuiltinCommonTypeDecl();
+#define BuiltinTemplate(BTName)                                                \
+  case PREDEF_DECL##BTName##_ID:                                               \
+    if (Context.Decl##BTName)                                                  \
+      return Context.Decl##BTName;                                             \
+    NewLoaded = Context.get##BTName##Decl();                                   \
     break;
+#include "clang/Basic/BuiltinTemplates.inc"
 
   case NUM_PREDEF_DECL_IDS:
     llvm_unreachable("Invalid decl ID");
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 79b777c..a01e72f 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5539,15 +5539,13 @@ void ASTWriter::PrepareWritingSpecialDecls(Sema &SemaRef) {
   RegisterPredefDecl(Context.MSGuidTagDecl,
                      PREDEF_DECL_BUILTIN_MS_GUID_ID);
   RegisterPredefDecl(Context.ExternCContext, PREDEF_DECL_EXTERN_C_CONTEXT_ID);
-  RegisterPredefDecl(Context.MakeIntegerSeqDecl,
-                     PREDEF_DECL_MAKE_INTEGER_SEQ_ID);
   RegisterPredefDecl(Context.CFConstantStringTypeDecl,
                      PREDEF_DECL_CF_CONSTANT_STRING_ID);
   RegisterPredefDecl(Context.CFConstantStringTagDecl,
                      PREDEF_DECL_CF_CONSTANT_STRING_TAG_ID);
-  RegisterPredefDecl(Context.TypePackElementDecl,
-                     PREDEF_DECL_TYPE_PACK_ELEMENT_ID);
-  RegisterPredefDecl(Context.BuiltinCommonTypeDecl, PREDEF_DECL_COMMON_TYPE_ID);
+#define BuiltinTemplate(BTName)                                                \
+  RegisterPredefDecl(Context.Decl##BTName, PREDEF_DECL##BTName##_ID);
+#include "clang/Basic/BuiltinTemplates.inc"
 
   const TranslationUnitDecl *TU = Context.getTranslationUnitDecl();