Replace TypeLoc llvm::cast support to be well-defined.

The TypeLoc hierarchy used the llvm::cast machinery to perform undefined
behavior by casting pointers/references to TypeLoc objects to derived types
and then using the derived copy constructors (or even returning pointers to
derived types that actually point to the original TypeLoc object).

Some context is in this thread:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056804.html
Though it's spread over a few months which can be hard to read in the mail
archive.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175462 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 10 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 763a4ce774..1711c8726e 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -3757,7 +3757,7 @@ struct CheckAbstractUsage {
     switch (TL.getTypeLocClass()) {
 #define ABSTRACT_TYPELOC(CLASS, PARENT)
 #define TYPELOC(CLASS, PARENT) \
-    case TypeLoc::CLASS: Check(cast<CLASS##TypeLoc>(TL), Sel); break;
+    case TypeLoc::CLASS: Check(TL.castAs<CLASS##TypeLoc>(), Sel); break;
 #include "clang/AST/TypeLocNodes.def"
     }
   }
@@ -10432,15 +10432,16 @@ Decl *Sema::ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
 
     TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
     if (isa<DependentNameType>(T)) {
-      DependentNameTypeLoc TL = cast<DependentNameTypeLoc>(TSI->getTypeLoc());
+      DependentNameTypeLoc TL =
+          TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
       TL.setElaboratedKeywordLoc(TagLoc);
       TL.setQualifierLoc(QualifierLoc);
       TL.setNameLoc(NameLoc);
     } else {
-      ElaboratedTypeLoc TL = cast<ElaboratedTypeLoc>(TSI->getTypeLoc());
+      ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
       TL.setElaboratedKeywordLoc(TagLoc);
       TL.setQualifierLoc(QualifierLoc);
-      cast<TypeSpecTypeLoc>(TL.getNamedTypeLoc()).setNameLoc(NameLoc);
+      TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(NameLoc);
     }
 
     FriendDecl *Friend = FriendDecl::Create(Context, CurContext, NameLoc,
@@ -10460,7 +10461,7 @@ Decl *Sema::ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
   ElaboratedTypeKeyword ETK = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
   QualType T = Context.getDependentNameType(ETK, SS.getScopeRep(), Name);
   TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
-  DependentNameTypeLoc TL = cast<DependentNameTypeLoc>(TSI->getTypeLoc());
+  DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
   TL.setElaboratedKeywordLoc(TagLoc);
   TL.setQualifierLoc(SS.getWithLocInContext(Context));
   TL.setNameLoc(NameLoc);
@@ -11538,7 +11539,7 @@ bool Sema::checkThisInStaticMemberFunctionType(CXXMethodDecl *Method) {
     return false;
   
   TypeLoc TL = TSInfo->getTypeLoc();
-  FunctionProtoTypeLoc *ProtoTL = dyn_cast<FunctionProtoTypeLoc>(&TL);
+  FunctionProtoTypeLoc ProtoTL = TL.getAs<FunctionProtoTypeLoc>();
   if (!ProtoTL)
     return false;
   
@@ -11549,12 +11550,12 @@ bool Sema::checkThisInStaticMemberFunctionType(CXXMethodDecl *Method) {
   //   within a static member function as they are within a non-static member
   //   function). [ Note: this is because declaration matching does not occur
   //  until the complete declarator is known. - end note ]
-  const FunctionProtoType *Proto = ProtoTL->getTypePtr();
+  const FunctionProtoType *Proto = ProtoTL.getTypePtr();
   FindCXXThisExpr Finder(*this);
   
   // If the return type came after the cv-qualifier-seq, check it now.
   if (Proto->hasTrailingReturn() &&
-      !Finder.TraverseTypeLoc(ProtoTL->getResultLoc()))
+      !Finder.TraverseTypeLoc(ProtoTL.getResultLoc()))
     return true;
 
   // Check the exception specification.
@@ -11570,11 +11571,11 @@ bool Sema::checkThisInStaticMemberFunctionExceptionSpec(CXXMethodDecl *Method) {
     return false;
   
   TypeLoc TL = TSInfo->getTypeLoc();
-  FunctionProtoTypeLoc *ProtoTL = dyn_cast<FunctionProtoTypeLoc>(&TL);
+  FunctionProtoTypeLoc ProtoTL = TL.getAs<FunctionProtoTypeLoc>();
   if (!ProtoTL)
     return false;
   
-  const FunctionProtoType *Proto = ProtoTL->getTypePtr();
+  const FunctionProtoType *Proto = ProtoTL.getTypePtr();
   FindCXXThisExpr Finder(*this);
 
   switch (Proto->getExceptionSpecType()) {