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, 17 insertions, 18 deletions

diff --git a/lib/Sema/SemaCodeComplete.cpp b/lib/Sema/SemaCodeComplete.cpp
index e145d3ff66..f894a0ba27 100644
--- a/lib/Sema/SemaCodeComplete.cpp
+++ b/lib/Sema/SemaCodeComplete.cpp
@@ -2147,36 +2147,35 @@ static std::string FormatFunctionParameter(ASTContext &Context,
   
   // The argument for a block pointer parameter is a block literal with
   // the appropriate type.
-  FunctionTypeLoc *Block = 0;
-  FunctionProtoTypeLoc *BlockProto = 0;
+  FunctionTypeLoc Block;
+  FunctionProtoTypeLoc BlockProto;
   TypeLoc TL;
   if (TypeSourceInfo *TSInfo = Param->getTypeSourceInfo()) {
     TL = TSInfo->getTypeLoc().getUnqualifiedLoc();
     while (true) {
       // Look through typedefs.
       if (!SuppressBlock) {
-        if (TypedefTypeLoc *TypedefTL = dyn_cast<TypedefTypeLoc>(&TL)) {
-          if (TypeSourceInfo *InnerTSInfo
-              = TypedefTL->getTypedefNameDecl()->getTypeSourceInfo()) {
+        if (TypedefTypeLoc TypedefTL = TL.getAs<TypedefTypeLoc>()) {
+          if (TypeSourceInfo *InnerTSInfo =
+                  TypedefTL.getTypedefNameDecl()->getTypeSourceInfo()) {
             TL = InnerTSInfo->getTypeLoc().getUnqualifiedLoc();
             continue;
           }
         }
         
         // Look through qualified types
-        if (QualifiedTypeLoc *QualifiedTL = dyn_cast<QualifiedTypeLoc>(&TL)) {
-          TL = QualifiedTL->getUnqualifiedLoc();
+        if (QualifiedTypeLoc QualifiedTL = TL.getAs<QualifiedTypeLoc>()) {
+          TL = QualifiedTL.getUnqualifiedLoc();
           continue;
         }
       }
       
       // Try to get the function prototype behind the block pointer type,
       // then we're done.
-      if (BlockPointerTypeLoc *BlockPtr
-          = dyn_cast<BlockPointerTypeLoc>(&TL)) {
-        TL = BlockPtr->getPointeeLoc().IgnoreParens();
-        Block = dyn_cast<FunctionTypeLoc>(&TL);
-        BlockProto = dyn_cast<FunctionProtoTypeLoc>(&TL);
+      if (BlockPointerTypeLoc BlockPtr = TL.getAs<BlockPointerTypeLoc>()) {
+        TL = BlockPtr.getPointeeLoc().IgnoreParens();
+        Block = TL.getAs<FunctionTypeLoc>();
+        BlockProto = TL.getAs<FunctionProtoTypeLoc>();
       }
       break;
     }
@@ -2204,27 +2203,27 @@ static std::string FormatFunctionParameter(ASTContext &Context,
   // We have the function prototype behind the block pointer type, as it was
   // written in the source.
   std::string Result;
-  QualType ResultType = Block->getTypePtr()->getResultType();
+  QualType ResultType = Block.getTypePtr()->getResultType();
   if (!ResultType->isVoidType() || SuppressBlock)
     ResultType.getAsStringInternal(Result, Policy);
 
   // Format the parameter list.
   std::string Params;
-  if (!BlockProto || Block->getNumArgs() == 0) {
-    if (BlockProto && BlockProto->getTypePtr()->isVariadic())
+  if (!BlockProto || Block.getNumArgs() == 0) {
+    if (BlockProto && BlockProto.getTypePtr()->isVariadic())
       Params = "(...)";
     else
       Params = "(void)";
   } else {
     Params += "(";
-    for (unsigned I = 0, N = Block->getNumArgs(); I != N; ++I) {
+    for (unsigned I = 0, N = Block.getNumArgs(); I != N; ++I) {
       if (I)
         Params += ", ";
-      Params += FormatFunctionParameter(Context, Policy, Block->getArg(I),
+      Params += FormatFunctionParameter(Context, Policy, Block.getArg(I),
                                         /*SuppressName=*/false, 
                                         /*SuppressBlock=*/true);
       
-      if (I == N - 1 && BlockProto->getTypePtr()->isVariadic())
+      if (I == N - 1 && BlockProto.getTypePtr()->isVariadic())
         Params += ", ...";
     }
     Params += ")";