[Sema] Implement __make_integer_seq

This new builtin template allows for incredibly fast instantiations of templates like std::integer_sequence. Performance numbers follow: My work station has 64 GB of ram + 20 Xeon Cores at 2.8 GHz. __make_integer_seq<std::integer_sequence, int, 90000> takes 0.25 seconds. std::make_integer_sequence<int, 90000> takes unbound time, it is still running. Clang is consuming gigabytes of memory. Differential Revision: http://reviews.llvm.org/D13786 git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@252036 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-mirror · Nov 4, 2015 · 6bb02a2 · 6bb02a2
1 parent 0c29653
commit 6bb02a2
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Showing 23 changed files with 308 additions and 4 deletions.
diff --git a/include/clang/AST/ASTContext.h b/include/clang/AST/ASTContext.h
@@ -70,6 +70,7 @@ namespace clang {
   class VTableContextBase;
 
   namespace Builtin { class Context; }
+  enum BuiltinTemplateKind : int;
 
   namespace comments {
     class FullComment;
@@ -246,6 +247,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
   /// The identifier 'NSCopying'.
   IdentifierInfo *NSCopyingName = nullptr;
 
+  /// The identifier '__make_integer_seq'.
+  mutable IdentifierInfo *MakeIntegerSeqName = nullptr;
+
   QualType ObjCConstantStringType;
   mutable RecordDecl *CFConstantStringTypeDecl;
 
@@ -399,6 +403,7 @@ class ASTContext : public RefCountedBase<ASTContext> {
 
   TranslationUnitDecl *TUDecl;
   mutable ExternCContextDecl *ExternCContext;
+  mutable BuiltinTemplateDecl *MakeIntegerSeqDecl;
 
   /// \brief The associated SourceManager object.a
   SourceManager &SourceMgr;
@@ -868,6 +873,7 @@ class ASTContext : public RefCountedBase<ASTContext> {
   TranslationUnitDecl *getTranslationUnitDecl() const { return TUDecl; }
 
   ExternCContextDecl *getExternCContextDecl() const;
+  BuiltinTemplateDecl *getMakeIntegerSeqDecl() const;
 
   // Builtin Types.
   CanQualType VoidTy;
@@ -941,6 +947,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
   void PrintStats() const;
   const SmallVectorImpl<Type *>& getTypes() const { return Types; }
 
+  BuiltinTemplateDecl *buildBuiltinTemplateDecl(BuiltinTemplateKind BTK,
+                                                const IdentifierInfo *II) const;
+
   /// \brief Create a new implicit TU-level CXXRecordDecl or RecordDecl
   /// declaration.
   RecordDecl *buildImplicitRecord(StringRef Name,
@@ -1444,6 +1453,12 @@ class ASTContext : public RefCountedBase<ASTContext> {
     return NSCopyingName;
   }
 
+  IdentifierInfo *getMakeIntegerSeqName() const {
+    if (!MakeIntegerSeqName)
+      MakeIntegerSeqName = &Idents.get("__make_integer_seq");
+    return MakeIntegerSeqName;
+  }
+
   /// \brief Retrieve the Objective-C "instancetype" type, if already known;
   /// otherwise, returns a NULL type;
   QualType getObjCInstanceType() {

diff --git a/include/clang/AST/DataRecursiveASTVisitor.h b/include/clang/AST/DataRecursiveASTVisitor.h
@@ -1551,6 +1551,10 @@ DEF_TRAVERSE_DECL(FunctionTemplateDecl, {
     TRY_TO(TraverseFunctionInstantiations(D));
 })
 
+DEF_TRAVERSE_DECL(BuiltinTemplateDecl, {
+  TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
+})
+
 DEF_TRAVERSE_DECL(TemplateTemplateParmDecl, {
   // D is the "T" in something like
   //   template <template <typename> class T> class container { };

diff --git a/include/clang/AST/DeclTemplate.h b/include/clang/AST/DeclTemplate.h
@@ -25,6 +25,7 @@
 
 namespace clang {
 
+enum BuiltinTemplateKind : int;
 class TemplateParameterList;
 class TemplateDecl;
 class RedeclarableTemplateDecl;
@@ -1490,6 +1491,35 @@ class TemplateTemplateParmDecl final
   friend TrailingObjects;
 };
 
+/// \brief Represents the builtin template declaration which is used to
+/// implement __make_integer_seq.  It serves no real purpose beyond existing as
+/// a place to hold template parameters.
+class BuiltinTemplateDecl : public TemplateDecl {
+  void anchor() override;
+
+  BuiltinTemplateDecl(const ASTContext &C, DeclContext *DC,
+                      DeclarationName Name, BuiltinTemplateKind BTK);
+
+  BuiltinTemplateKind BTK;
+
+public:
+  // Implement isa/cast/dyncast support
+  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
+  static bool classofKind(Kind K) { return K == BuiltinTemplate; }
+
+  static BuiltinTemplateDecl *Create(const ASTContext &C, DeclContext *DC,
+                                     DeclarationName Name,
+                                     BuiltinTemplateKind BTK) {
+    return new (C, DC) BuiltinTemplateDecl(C, DC, Name, BTK);
+  }
+
+  SourceRange getSourceRange() const override LLVM_READONLY {
+    return SourceRange();
+  }
+
+  BuiltinTemplateKind getBuiltinTemplateKind() const { return BTK; }
+};
+
 /// \brief Represents a class template specialization, which refers to
 /// a class template with a given set of template arguments.
 ///

diff --git a/include/clang/AST/RecursiveASTVisitor.h b/include/clang/AST/RecursiveASTVisitor.h
@@ -1603,6 +1603,10 @@ DEF_TRAVERSE_DECL(TemplateTemplateParmDecl, {
   TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
 })
 
+DEF_TRAVERSE_DECL(BuiltinTemplateDecl, {
+  TRY_TO(TraverseTemplateParameterListHelper(D->getTemplateParameters()));
+})
+
 DEF_TRAVERSE_DECL(TemplateTypeParmDecl, {
   // D is the "T" in something like "template<typename T> class vector;"
   if (D->getTypeForDecl())

diff --git a/include/clang/Basic/Builtins.h b/include/clang/Basic/Builtins.h
@@ -205,5 +205,12 @@ class Context {
 };
 
 }
+
+/// \brief Kinds of BuiltinTemplateDecl.
+enum BuiltinTemplateKind : int {
+  /// \brief This names the __make_integer_seq BuiltinTemplateDecl.
+  BTK__make_integer_seq
+};
+
 } // end namespace clang
 #endif
diff --git a/include/clang/Basic/DeclNodes.td b/include/clang/Basic/DeclNodes.td
@@ -59,6 +59,7 @@ def Named : Decl<1>;
       def VarTemplate : DDecl<RedeclarableTemplate>;
       def TypeAliasTemplate : DDecl<RedeclarableTemplate>;
     def TemplateTemplateParm : DDecl<Template>;
+    def BuiltinTemplate : DDecl<Template>;
   def Using : DDecl<Named>;
   def UsingShadow : DDecl<Named>;
   def ObjCMethod : DDecl<Named>, DeclContext;

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1995,7 +1995,13 @@ def err_concept_decl_invalid_specifiers : Error<
 def warn_cxx98_compat_unicode_type : Warning<
   "'%0' type specifier is incompatible with C++98">,
   InGroup<CXX98Compat>, DefaultIgnore;
-
+
+// __make_integer_seq
+def err_integer_sequence_negative_length : Error<
+  "integer sequences must have non-negative sequence length">;
+def err_integer_sequence_integral_element_type : Error<
+  "integer sequences must have integral element type">;
+
 // Objective-C++
 def err_objc_decls_may_only_appear_in_global_scope : Error<
   "Objective-C declarations may only appear in global scope">;

diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
@@ -982,13 +982,16 @@ namespace clang {
 
       /// \brief The extern "C" context.
       PREDEF_DECL_EXTERN_C_CONTEXT_ID = 12,
+
+      /// \brief The internal '__make_integer_seq' template.
+      PREDEF_DECL_MAKE_INTEGER_SEQ_ID = 13,
     };
 
     /// \brief The number of declaration IDs that are predefined.
     ///
     /// For more information about predefined declarations, see the
     /// \c PredefinedDeclIDs type and the PREDEF_DECL_*_ID constants.
-    const unsigned int NUM_PREDEF_DECL_IDS = 13;
+    const unsigned int NUM_PREDEF_DECL_IDS = 14;
 
     /// \brief Record code for a list of local redeclarations of a declaration.
     const unsigned int LOCAL_REDECLARATIONS = 50;

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
@@ -744,7 +744,7 @@ ASTContext::ASTContext(LangOptions &LOpts, SourceManager &SM,
       ucontext_tDecl(nullptr), BlockDescriptorType(nullptr),
       BlockDescriptorExtendedType(nullptr), cudaConfigureCallDecl(nullptr),
       FirstLocalImport(), LastLocalImport(), ExternCContext(nullptr),
-      SourceMgr(SM), LangOpts(LOpts),
+      MakeIntegerSeqDecl(nullptr), SourceMgr(SM), LangOpts(LOpts),
       SanitizerBL(new SanitizerBlacklist(LangOpts.SanitizerBlacklistFiles, SM)),
       AddrSpaceMap(nullptr), Target(nullptr), AuxTarget(nullptr),
       PrintingPolicy(LOpts), Idents(idents), Selectors(sels),
@@ -913,6 +913,24 @@ ExternCContextDecl *ASTContext::getExternCContextDecl() const {
   return ExternCContext;
 }
 
+BuiltinTemplateDecl *
+ASTContext::buildBuiltinTemplateDecl(BuiltinTemplateKind BTK,
+                                     const IdentifierInfo *II) const {
+  auto *BuiltinTemplate = BuiltinTemplateDecl::Create(*this, TUDecl, II, BTK);
+  BuiltinTemplate->setImplicit();
+  TUDecl->addDecl(BuiltinTemplate);
+
+  return BuiltinTemplate;
+}
+
+BuiltinTemplateDecl *
+ASTContext::getMakeIntegerSeqDecl() const {
+  if (!MakeIntegerSeqDecl)
+    MakeIntegerSeqDecl = buildBuiltinTemplateDecl(BTK__make_integer_seq,
+                                                  getMakeIntegerSeqName());
+  return MakeIntegerSeqDecl;
+}
+
 RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
                                             RecordDecl::TagKind TK) const {
   SourceLocation Loc;

diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
@@ -21,6 +21,7 @@
 #include "clang/AST/DeclVisitor.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/AST/TypeVisitor.h"
+#include "clang/Basic/Builtins.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/Support/raw_ostream.h"
@@ -447,6 +448,7 @@ namespace  {
         const ClassTemplatePartialSpecializationDecl *D);
     void VisitClassScopeFunctionSpecializationDecl(
         const ClassScopeFunctionSpecializationDecl *D);
+    void VisitBuiltinTemplateDecl(const BuiltinTemplateDecl *D);
     void VisitVarTemplateDecl(const VarTemplateDecl *D);
     void VisitVarTemplateSpecializationDecl(
         const VarTemplateSpecializationDecl *D);
@@ -1333,6 +1335,11 @@ void ASTDumper::VisitVarTemplateDecl(const VarTemplateDecl *D) {
   VisitTemplateDecl(D, false);
 }
 
+void ASTDumper::VisitBuiltinTemplateDecl(const BuiltinTemplateDecl *D) {
+  dumpName(D);
+  dumpTemplateParameters(D->getTemplateParameters());
+}
+
 void ASTDumper::VisitVarTemplateSpecializationDecl(
     const VarTemplateSpecializationDecl *D) {
   dumpTemplateArgumentList(D->getTemplateArgs());

diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
@@ -639,6 +639,7 @@ unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
     case ExternCContext:
 
     case UsingDirective:
+    case BuiltinTemplate:
     case ClassTemplateSpecialization:
     case ClassTemplatePartialSpecialization:
     case ClassScopeFunctionSpecialization:

diff --git a/lib/AST/DeclTemplate.cpp b/lib/AST/DeclTemplate.cpp
@@ -18,6 +18,7 @@
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/TypeLoc.h"
+#include "clang/Basic/Builtins.h"
 #include "clang/Basic/IdentifierTable.h"
 #include "llvm/ADT/STLExtras.h"
 #include <memory>
@@ -1191,3 +1192,69 @@ VarTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
                                                          unsigned ID) {
   return new (C, ID) VarTemplatePartialSpecializationDecl(C);
 }
+
+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);
+  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, 2, SourceLocation());
+
+  // template <typename T, ...Ints> class IntSeq
+  auto *TemplateTemplateParm = TemplateTemplateParmDecl::Create(
+      C, DC, SourceLocation(), /*Depth=*/0, /*Position=*/0,
+      /*ParameterPack=*/false, /*Id=*/nullptr, TPL);
+  TemplateTemplateParm->setImplicit(true);
+
+  // typename T
+  auto *TemplateTypeParm = TemplateTypeParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
+      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/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, 3, SourceLocation());
+}
+
+static TemplateParameterList *createBuiltinTemplateParameterList(
+    const ASTContext &C, DeclContext *DC, BuiltinTemplateKind BTK) {
+  switch (BTK) {
+  case BTK__make_integer_seq:
+    return createMakeIntegerSeqParameterList(C, DC);
+  }
+
+  llvm_unreachable("unhandled BuiltinTemplateKind!");
+}
+
+void BuiltinTemplateDecl::anchor() {}
+
+BuiltinTemplateDecl::BuiltinTemplateDecl(const ASTContext &C, DeclContext *DC,
+                                         DeclarationName Name,
+                                         BuiltinTemplateKind BTK)
+    : TemplateDecl(BuiltinTemplate, DC, SourceLocation(), Name,
+                   createBuiltinTemplateParameterList(C, DC, BTK)),
+      BTK(BTK) {}
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
@@ -35,6 +35,7 @@ using namespace CodeGen;
 
 void CodeGenFunction::EmitDecl(const Decl &D) {
   switch (D.getKind()) {
+  case Decl::BuiltinTemplate:
   case Decl::TranslationUnit:
   case Decl::ExternCContext:
   case Decl::Namespace:

diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
@@ -627,6 +627,11 @@ static bool LookupBuiltin(Sema &S, LookupResult &R) {
         R.addDecl(S.getASTContext().getFloat128StubType());
         return true;
       }
+      if (S.getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName &&
+          II == S.getASTContext().getMakeIntegerSeqName()) {
+        R.addDecl(S.getASTContext().getMakeIntegerSeqDecl());
+        return true;
+      }
 
       // If this is a builtin on this (or all) targets, create the decl.
       if (unsigned BuiltinID = II->getBuiltinID()) {