Fix checking for a null pointer constant when the expression itself is
value-dependent. Audit (and fixed) all calls to
Expr::isNullPointerConstant() to provide the correct behavior with
value-dependent expressions. Fixes PR5041 and a crash in libstdc++
<locale>.
In the same vein, properly compute value- and type-dependence for
ChooseExpr. Fixes PR4996.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@82748 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index dc9cee1..dcfd147 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1625,9 +1625,21 @@
/// isNullPointerConstant - C99 6.3.2.3p3 - Return true if this is either an
/// integer constant expression with the value zero, or if this is one that is
/// cast to void*.
-bool Expr::isNullPointerConstant(ASTContext &Ctx) const {
- // Ignore value dependent expressions.
- assert(!isValueDependent() && "Unexpect value dependent expression!");
+bool Expr::isNullPointerConstant(ASTContext &Ctx,
+ NullPointerConstantValueDependence NPC) const {
+ if (isValueDependent()) {
+ switch (NPC) {
+ case NPC_NeverValueDependent:
+ assert(false && "Unexpected value dependent expression!");
+ // If the unthinkable happens, fall through to the safest alternative.
+
+ case NPC_ValueDependentIsNull:
+ return isTypeDependent() || getType()->isIntegralType();
+
+ case NPC_ValueDependentIsNotNull:
+ return false;
+ }
+ }
// Strip off a cast to void*, if it exists. Except in C++.
if (const ExplicitCastExpr *CE = dyn_cast<ExplicitCastExpr>(this)) {
@@ -1638,20 +1650,20 @@
if (!Pointee.hasQualifiers() &&
Pointee->isVoidType() && // to void*
CE->getSubExpr()->getType()->isIntegerType()) // from int.
- return CE->getSubExpr()->isNullPointerConstant(Ctx);
+ return CE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
}
}
} else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
// Ignore the ImplicitCastExpr type entirely.
- return ICE->getSubExpr()->isNullPointerConstant(Ctx);
+ return ICE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
} else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
// Accept ((void*)0) as a null pointer constant, as many other
// implementations do.
- return PE->getSubExpr()->isNullPointerConstant(Ctx);
+ return PE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
} else if (const CXXDefaultArgExpr *DefaultArg
= dyn_cast<CXXDefaultArgExpr>(this)) {
// See through default argument expressions
- return DefaultArg->getExpr()->isNullPointerConstant(Ctx);
+ return DefaultArg->getExpr()->isNullPointerConstant(Ctx, NPC);
} else if (isa<GNUNullExpr>(this)) {
// The GNU __null extension is always a null pointer constant.
return true;