Concepts: Create space for requires-clause in TemplateParameterList; NFC

Summary:
Space for storing the //constraint-expression// of the
//requires-clause// associated with a `TemplateParameterList` is
arranged by taking a bit out of the `NumParams` field for the purpose
of determining whether there is a //requires-clause// or not, and by
adding to the trailing objects tied to the `TemplateParameterList`. An
accessor is provided.

An appropriate argument is supplied to `TemplateParameterList::Create`
at the various call sites.

Serialization changes will addressed as the Concepts implementation
becomes more solid.

Drive-by fix:
This change also replaces the custom
`FixedSizeTemplateParameterListStorage` implementation with one that
follows the interface provided by `llvm::TrailingObjects`.

Reviewers: aaron.ballman, faisalv, rsmith

Subscribers: cfe-commits, nwilson

Differential Revision: https://reviews.llvm.org/D19322

llvm-svn: 276069

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index b35bd7bd329..ddf3a1b4115 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7892,9 +7892,10 @@ ASTReader::ReadTemplateParameterList(ModuleFile &F,
   while (NumParams--)
     Params.push_back(ReadDeclAs<NamedDecl>(F, Record, Idx));
 
+  // TODO: Concepts
   TemplateParameterList* TemplateParams =
     TemplateParameterList::Create(Context, TemplateLoc, LAngleLoc,
-                                  Params, RAngleLoc);
+                                  Params, RAngleLoc, nullptr);
   return TemplateParams;
 }