Perform dynamic alignment computations so that the data in TypeLocs is

correctly aligned.  Not performing such computations led to misaligned loads,
which crash on some platforms and are generally bad on other platforms.

The implementation of TypeLocBuilder::pushImpl is rather messy; code using
TypeLocBuilder accidentally assumes that partial TypeLocs are
laid out like a complete TypeLoc.  As a followup, I intend to work on
fixing the TypeLocBuilder API to avoid exposing partial TypeLocs; this should
substantially simplify the implemementation.

Fixes PR16144.

llvm-svn: 183466

1 files changed, 7 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 3b8228016c5..cb6f4c19de0 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -18,6 +18,7 @@
 #include "clang/Sema/ScopeInfo.h"
 #include "clang/Sema/SemaInternal.h"
 #include "clang/Sema/Template.h"
+#include "TypeLocBuilder.h"
 
 using namespace clang;
 
@@ -463,17 +464,13 @@ Sema::CheckPackExpansion(TypeSourceInfo *Pattern, SourceLocation EllipsisLoc,
                                        EllipsisLoc, NumExpansions);
   if (Result.isNull())
     return 0;
-  
-  TypeSourceInfo *TSResult = Context.CreateTypeSourceInfo(Result);
-  PackExpansionTypeLoc TL =
-      TSResult->getTypeLoc().castAs<PackExpansionTypeLoc>();
+
+  TypeLocBuilder TLB;
+  TLB.pushFullCopy(Pattern->getTypeLoc());
+  PackExpansionTypeLoc TL = TLB.push<PackExpansionTypeLoc>(Result);
   TL.setEllipsisLoc(EllipsisLoc);
-  
-  // Copy over the source-location information from the type.
-  memcpy(TL.getNextTypeLoc().getOpaqueData(),
-         Pattern->getTypeLoc().getOpaqueData(),
-         Pattern->getTypeLoc().getFullDataSize());
-  return TSResult;
+
+  return TLB.getTypeSourceInfo(Context, Result);
 }
 
 QualType Sema::CheckPackExpansion(QualType Pattern, SourceRange PatternRange,