For

double data[20000000] = {0};

we would blow out the memory by creating 20M Exprs to fill out the initializer.

To fix this, if the initializer list initializes an array with more elements than
there are initializers in the list, have InitListExpr store a single 'ArrayFiller' expression
that specifies an expression to be used for value initialization of the rest of the elements.

Fixes rdar://9275920.

llvm-svn: 129896

2 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 6fb9987ecd7..5b3c0905e54 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -641,6 +641,8 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
       
       if (i < NumInitElements)
         EmitInitializationToLValue(E->getInit(i), LV, ElementType);
+      else if (Expr *filler = E->getArrayFiller())
+        EmitInitializationToLValue(filler, LV, ElementType);
       else
         EmitNullInitializationToLValue(LV, ElementType);
       
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 8e26b206ebf..338fb03b8a0 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -667,8 +667,16 @@ public:
 
     // Initialize remaining array elements.
     // FIXME: This doesn't handle member pointers correctly!
+    llvm::Constant *fillC;
+    if (Expr *filler = ILE->getArrayFiller())
+      fillC = CGM.EmitConstantExpr(filler, filler->getType(), CGF);
+    else
+      fillC = llvm::Constant::getNullValue(ElemTy);
+    if (!fillC)
+      return 0;
+    RewriteType |= (fillC->getType() != ElemTy);
     for (; i < NumElements; ++i)
-      Elts.push_back(llvm::Constant::getNullValue(ElemTy));
+      Elts.push_back(fillC);
 
     if (RewriteType) {
       // FIXME: Try to avoid packing the array