nicholas updated this revision to Diff 56236.
nicholas added a comment.
(Whoops, forgot to generate diff with full context for phab.)
http://reviews.llvm.org/D19851
Files:
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaInit.cpp
test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
test/Parser/cxx-casting.cpp
test/SemaCXX/cstyle-cast.cpp
test/SemaCXX/functional-cast.cpp
test/SemaCXX/new-delete.cpp
test/SemaCXX/static-cast.cpp
Index: test/SemaCXX/static-cast.cpp
===================================================================
--- test/SemaCXX/static-cast.cpp
+++ test/SemaCXX/static-cast.cpp
@@ -43,11 +43,11 @@
(void)static_cast<void*>((int*)0);
(void)static_cast<volatile const void*>((const int*)0);
(void)static_cast<A*>((B*)0);
- (void)static_cast<A&>(*((B*)0));
+ (void)static_cast<A&>(*((B*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)static_cast<const B*>((C1*)0);
- (void)static_cast<B&>(*((C1*)0));
+ (void)static_cast<B&>(*((C1*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)static_cast<A*>((D*)0);
- (void)static_cast<const A&>(*((D*)0));
+ (void)static_cast<const A&>(*((D*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)static_cast<int B::*>((int A::*)0);
(void)static_cast<void (B::*)()>((void (A::*)())0);
Index: test/SemaCXX/new-delete.cpp
===================================================================
--- test/SemaCXX/new-delete.cpp
+++ test/SemaCXX/new-delete.cpp
@@ -444,11 +444,11 @@
template<typename X>
void tfn() {
- new (*(PlacementArg*)0) T[1];
+ new (*(PlacementArg*)0) T[1]; // expected-warning 2 {{binding null pointer to reference has undefined behavior}}
}
void fn() {
- tfn<int>();
+ tfn<int>(); // expected-note {{in instantiation of function template specialization 'r150682::tfn<int>' requested here}}
}
}
Index: test/SemaCXX/functional-cast.cpp
===================================================================
--- test/SemaCXX/functional-cast.cpp
+++ test/SemaCXX/functional-cast.cpp
@@ -126,14 +126,14 @@
typedef A *Ap;
(void)Ap((B*)0);
typedef A &Ar;
- (void)Ar(*((B*)0));
+ (void)Ar(*((B*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
typedef const B *cBp;
(void)cBp((C1*)0);
typedef B &Br;
- (void)Br(*((C1*)0));
+ (void)Br(*((C1*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)Ap((D*)0);
typedef const A &cAr;
- (void)cAr(*((D*)0));
+ (void)cAr(*((D*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
typedef int B::*Bmp;
(void)Bmp((int A::*)0);
typedef void (B::*Bmfp)();
Index: test/SemaCXX/cstyle-cast.cpp
===================================================================
--- test/SemaCXX/cstyle-cast.cpp
+++ test/SemaCXX/cstyle-cast.cpp
@@ -84,11 +84,11 @@
(void)(void*)((int*)0);
(void)(volatile const void*)((const int*)0);
(void)(A*)((B*)0);
- (void)(A&)(*((B*)0));
+ (void)(A&)(*((B*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)(const B*)((C1*)0);
- (void)(B&)(*((C1*)0));
+ (void)(B&)(*((C1*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)(A*)((D*)0);
- (void)(const A&)(*((D*)0));
+ (void)(const A&)(*((D*)0)); // expected-warning {{binding null pointer to reference has undefined behavior}}
(void)(int B::*)((int A::*)0);
(void)(void (B::*)())((void (A::*)())0);
(void)(A*)((E*)0); // C-style cast ignores access control
Index: test/Parser/cxx-casting.cpp
===================================================================
--- test/Parser/cxx-casting.cpp
+++ test/Parser/cxx-casting.cpp
@@ -37,7 +37,7 @@
// This was being incorrectly tentatively parsed.
namespace test1 {
template <class T> class A {}; // expected-note 2{{here}}
- void foo() { A<int>(*(A<int>*)0); }
+ void foo() { A<int>(*(A<int>*)0); } // expected-warning {{binding null pointer to reference has undefined behavior}}
}
typedef char* c;
Index: test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
===================================================================
--- test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
+++ test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
@@ -11,7 +11,7 @@
template<typename T>
struct bogus_override_if_virtual : public T {
- bogus_override_if_virtual() : T(*(T*)0) { }
+ bogus_override_if_virtual() : T(*(T*)0) { } // expected-warning {{binding null pointer to reference has undefined behavior}}
int operator()() const;
};
@@ -36,7 +36,7 @@
lv(); // expected-error{{no matching function for call to object of type}}
mlv(); // expected-error{{no matching function for call to object of type}}
- bogus_override_if_virtual<decltype(l)> bogus;
+ bogus_override_if_virtual<decltype(l)> bogus; // expected-note{{in instantiation of member function 'bogus_override_if_virtual<(lambda}}
}
// Core issue 974: default arguments (8.3.6) may be specified in the
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -6193,6 +6193,21 @@
<< FixItHint::CreateRemoval(SourceRange(RParen, RParen));
}
+static void CheckForNullPointerDereference(Sema &S, const Expr *E) {
+ // Check to see if we are dereferencing a null pointer. If so, this is
+ // undefined behavior, so warn about it. This only handles the pattern
+ // "*null", which is a very syntactic check.
+ if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
+ if (UO->getOpcode() == UO_Deref &&
+ UO->getSubExpr()->IgnoreParenCasts()->
+ isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) &&
+ !UO->getType().isVolatileQualified()) {
+ S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
+ S.PDiag(diag::warn_binding_null_to_reference)
+ << UO->getSubExpr()->getSourceRange());
+ }
+}
+
ExprResult
InitializationSequence::Perform(Sema &S,
const InitializedEntity &Entity,
@@ -6445,6 +6460,7 @@
/*IsInitializerList=*/false,
ExtendingEntity->getDecl());
+ CheckForNullPointerDereference(S, CurInit.get());
break;
case SK_BindReferenceToTemporary: {
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -5365,6 +5365,8 @@
InGroup<DiagGroup<"void-ptr-dereference">>;
def warn_indirection_through_null : Warning<
"indirection of non-volatile null pointer will be deleted, not trap">, InGroup<NullDereference>;
+def warn_binding_null_to_reference : Warning<
+ "binding null pointer to reference has undefined behavior">, InGroup<NullDereference>;
def note_indirection_through_null : Note<
"consider using __builtin_trap() or qualifying pointer with 'volatile'">;
def warn_pointer_indirection_from_incompatible_type : Warning<
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