Rewrite Expr::isNullPointerConstant() to deal with multiple levels of explicit casts.
Now, isNullPointerConstant() will return true for the following: "(void*)(double*)0"
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@45951 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/AST/Expr.cpp b/AST/Expr.cpp
index 61b02c3..61e997d 100644
--- a/AST/Expr.cpp
+++ b/AST/Expr.cpp
@@ -929,37 +929,47 @@
return true;
}
+/// Helper function for isNullPointerConstant. This routine skips all
+/// explicit casts, implicit casts and paren expressions.
+const Expr * getNullPointerConstantExpr(const Expr *exp) {
+ if (const CastExpr *CE = dyn_cast<CastExpr>(exp)) {
+ return getNullPointerConstantExpr(CE->getSubExpr());
+ } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(exp)) {
+ return getNullPointerConstantExpr(ICE->getSubExpr());
+ } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(exp)) {
+ // Accept ((void*)0) as a null pointer constant, as many other
+ // implementations do.
+ return getNullPointerConstantExpr(PE->getSubExpr());
+ }
+ return exp;
+}
/// 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 {
- // Strip off a cast to void*, if it exists.
- if (const CastExpr *CE = dyn_cast<CastExpr>(this)) {
- // Check that it is a cast to void*.
+ const CastExpr *CE = dyn_cast<CastExpr>(this);
+ const Expr *e = getNullPointerConstantExpr(this);
+
+ if (CE) {
+ bool castToVoidStar = false;
+ // Check if the highest precedence cast is "void *".
if (const PointerType *PT = dyn_cast<PointerType>(CE->getType())) {
QualType Pointee = PT->getPointeeType();
- if (Pointee.getQualifiers() == 0 && Pointee->isVoidType() && // to void*
- CE->getSubExpr()->getType()->isIntegerType()) // from int.
- return CE->getSubExpr()->isNullPointerConstant(Ctx);
+ if (Pointee.getQualifiers() == 0 && Pointee->isVoidType())
+ castToVoidStar = true;
}
- } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
- // Ignore the ImplicitCastExpr type entirely.
- return ICE->getSubExpr()->isNullPointerConstant(Ctx);
- } 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);
- }
-
- // This expression must be an integer type.
- if (!getType()->isIntegerType())
+ // This cast must be an integer type or void *.
+ if (!CE->getType()->isIntegerType() && !castToVoidStar)
+ return false;
+ } else if (!e->getType()->isIntegerType()) {
+ // This expression must be an integer type.
return false;
-
+ }
// If we have an integer constant expression, we need to *evaluate* it and
// test for the value 0.
llvm::APSInt Val(32);
- return isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
+ return e->isIntegerConstantExpr(Val, Ctx, 0, true) && Val == 0;
}
unsigned OCUVectorElementExpr::getNumElements() const {