Introduce a new OpaquePtr<N> struct type, which is a simple POD wrapper for a

pointer.  Its purpose in life is to be a glorified void*, but which does not
implicitly convert to void* or other OpaquePtr's with a different UID.

Introduce Action::DeclPtrTy which is a typedef for OpaquePtr<0>.  Change the 
entire parser/sema interface to use DeclPtrTy instead of DeclTy*.  This
makes the C++ compiler enforce that these aren't convertible to other opaque
types.

We should also convert ExprTy, StmtTy, TypeTy, AttrTy, BaseTy, etc,
but I don't plan to do that in the short term.

The one outstanding known problem with this patch is that we lose the 
bitmangling optimization where ActionResult<DeclPtrTy> doesn't know how to
bitmangle the success bit into the low bit of DeclPtrTy.  I will rectify
this with a subsequent patch.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67952 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 8 deletions

diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 4082d485b8..b331911099 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -37,14 +37,13 @@ Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) {
   return Owned(new (Context) NullStmt(SemiLoc));
 }
 
-Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclTy *decl,
+Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclPtrTy decl,
                                            SourceLocation StartLoc,
                                            SourceLocation EndLoc) {
-  if (decl == 0)
+  Decl *D = decl.getAs<Decl>();
+  if (D == 0)
     return StmtError();
 
-  Decl *D = static_cast<Decl *>(decl);
-
   // This is a temporary hack until we are always passing around
   // DeclGroupRefs.
   llvm::SmallVector<Decl*, 10> decls;
@@ -1001,10 +1000,10 @@ Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
 
 Action::OwningStmtResult
 Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc,
-                           SourceLocation RParen, DeclTy *Parm,
+                           SourceLocation RParen, DeclPtrTy Parm,
                            StmtArg Body, StmtArg catchList) {
   Stmt *CatchList = static_cast<Stmt*>(catchList.release());
-  ParmVarDecl *PVD = static_cast<ParmVarDecl*>(Parm);
+  ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>());
   
   // PVD == 0 implies @catch(...).
   if (PVD) {
@@ -1071,11 +1070,11 @@ Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr,
 /// ActOnCXXCatchBlock - Takes an exception declaration and a handler block
 /// and creates a proper catch handler from them.
 Action::OwningStmtResult
-Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclTy *ExDecl,
+Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl,
                          StmtArg HandlerBlock) {
   // There's nothing to test that ActOnExceptionDecl didn't already test.
   return Owned(new (Context) CXXCatchStmt(CatchLoc,
-                                  static_cast<VarDecl*>(ExDecl),
+                                  cast_or_null<VarDecl>(ExDecl.getAs<Decl>()),
                                   static_cast<Stmt*>(HandlerBlock.release())));
 }