[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

llvm-svn: 252036

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/AST/ASTDumper.cpp b/clang/lib/AST/ASTDumper.cpp
index 0c9c14ba308..d5e5372f01f 100644
--- a/clang/lib/AST/ASTDumper.cpp
+++ b/clang/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());