[Sema] Don't try to account for the size of an incomplete type in CheckArrayAccess
When checking that the array access is not out-of-bounds in CheckArrayAccess
it is possible that the type of the base expression after IgnoreParenCasts is
incomplete, even though the type of the base expression before IgnoreParenCasts
is complete. In this case we have no information about whether the array access
is out-of-bounds and we should just bail-out instead. This fixes PR39746 which
was caused by trying to obtain the size of an incomplete type.
Differential Revision: https://reviews.llvm.org/D55862
Reviewed By: efriedma
llvm-svn: 349811
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index b06f793..9fe65c1 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -12379,10 +12379,19 @@
BaseExpr->getType()->getPointeeOrArrayElementType();
BaseExpr = BaseExpr->IgnoreParenCasts();
const ConstantArrayType *ArrayTy =
- Context.getAsConstantArrayType(BaseExpr->getType());
+ Context.getAsConstantArrayType(BaseExpr->getType());
+
if (!ArrayTy)
return;
+ const Type *BaseType = ArrayTy->getElementType().getTypePtr();
+ // It is possible that the type of the base expression after IgnoreParenCasts
+ // is incomplete, even though the type of the base expression before
+ // IgnoreParenCasts is complete (see PR39746 for an example). In this case we
+ // have no information about whether the array access is out-of-bounds.
+ if (BaseType->isIncompleteType())
+ return;
+
Expr::EvalResult Result;
if (!IndexExpr->EvaluateAsInt(Result, Context, Expr::SE_AllowSideEffects))
return;
@@ -12402,7 +12411,6 @@
if (!size.isStrictlyPositive())
return;
- const Type *BaseType = BaseExpr->getType()->getPointeeOrArrayElementType();
if (BaseType != EffectiveType) {
// Make sure we're comparing apples to apples when comparing index to size
uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType);