Plug a long standing memory leak in TemplateArgument.

The integral APSInt value is now stored in a decomposed form and the backing
store for large values is allocated via the ASTContext. This way its not
leaked as TemplateArguments are never destructed when they are allocated in
the ASTContext. Since the integral data is immutable it is now shared between
instances, making copying TemplateArguments a trivial operation.

Currently getting the integral data out of a TemplateArgument requires creating
a new APSInt object. This is cheap when the value is small but can be expensive
if it's not. If this turns out to be an issue a more efficient accessor could
be added.

llvm-svn: 158150

1 files changed, 6 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index e6f2b2d649a..78a860c53da 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -193,7 +193,7 @@ checkDeducedTemplateArguments(ASTContext &Context,
     if (Y.getKind() == TemplateArgument::Expression ||
         Y.getKind() == TemplateArgument::Declaration ||
         (Y.getKind() == TemplateArgument::Integral &&
-         hasSameExtendedValue(*X.getAsIntegral(), *Y.getAsIntegral())))
+         hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
       return DeducedTemplateArgument(X,
                                      X.wasDeducedFromArrayBound() &&
                                      Y.wasDeducedFromArrayBound());
@@ -293,7 +293,8 @@ DeduceNonTypeTemplateArgument(Sema &S,
   assert(NTTP->getDepth() == 0 &&
          "Cannot deduce non-type template argument with depth > 0");
 
-  DeducedTemplateArgument NewDeduced(Value, ValueType, DeducedFromArrayBound);
+  DeducedTemplateArgument NewDeduced(S.Context, Value, ValueType,
+                                     DeducedFromArrayBound);
   DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
                                                      Deduced[NTTP->getIndex()],
                                                                  NewDeduced);
@@ -1595,7 +1596,7 @@ DeduceTemplateArguments(Sema &S,
 
   case TemplateArgument::Integral:
     if (Arg.getKind() == TemplateArgument::Integral) {
-      if (hasSameExtendedValue(*Param.getAsIntegral(), *Arg.getAsIntegral()))
+      if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral()))
         return Sema::TDK_Success;
 
       Info.FirstArg = Param;
@@ -1618,7 +1619,7 @@ DeduceTemplateArguments(Sema &S,
           = getDeducedParameterFromExpr(Param.getAsExpr())) {
       if (Arg.getKind() == TemplateArgument::Integral)
         return DeduceNonTypeTemplateArgument(S, NTTP,
-                                             *Arg.getAsIntegral(),
+                                             Arg.getAsIntegral(),
                                              Arg.getIntegralType(),
                                              /*ArrayBound=*/false,
                                              Info, Deduced);
@@ -1867,7 +1868,7 @@ static bool isSameTemplateArg(ASTContext &Context,
                     Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer();
 
     case TemplateArgument::Integral:
-      return *X.getAsIntegral() == *Y.getAsIntegral();
+      return X.getAsIntegral() == Y.getAsIntegral();
 
     case TemplateArgument::Expression: {
       llvm::FoldingSetNodeID XID, YID;