Add a warning for Objective-C pointer introspection, which is solely the job of the Objective-C runtime.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180062 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index c7daf0b..0f73c7b 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -642,6 +642,10 @@
def warn_objc_isa_assign : Warning<
"assignment to Objective-C's isa is deprecated in favor of "
"object_setClass()">, InGroup<DeprecatedObjCIsaUsage>;
+def warn_objc_pointer_masking : Warning<
+ "bitmasking for introspection of Objective-C object pointers is strongly "
+ "discouraged in favor of using runtime APIs">,
+ InGroup<DiagGroup<"deprecated-objc-pointer-introspection">>;
def warn_objc_property_default_assign_on_object : Warning<
"default property attribute 'assign' not appropriate for non-GC object">,
InGroup<ObjCPropertyNoAttribute>;
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index fb0e9ef..a0e6c21 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -8559,6 +8559,36 @@
<< LHSExpr->getSourceRange() << RHSExpr->getSourceRange();
}
+/// Check if a bitwise-& is performed on an Objective-C pointer. This
+/// is usually indicative of introspection within the Objective-C pointer.
+static void checkObjCPointerIntrospection(Sema &S, ExprResult &L, ExprResult &R,
+ SourceLocation OpLoc) {
+ if (!S.getLangOpts().ObjC1)
+ return;
+
+ const Expr *ObjCPointerExpr = 0, *OtherExpr = 0;
+ const Expr *LHS = L.get();
+ const Expr *RHS = R.get();
+
+ if (LHS->IgnoreParenCasts()->getType()->isObjCObjectPointerType()) {
+ ObjCPointerExpr = LHS;
+ OtherExpr = RHS;
+ }
+ else if (RHS->IgnoreParenCasts()->getType()->isObjCObjectPointerType()) {
+ ObjCPointerExpr = RHS;
+ OtherExpr = LHS;
+ }
+
+ // This warning is deliberately made very specific to reduce false
+ // positives with logic that uses '&' for hashing. This logic mainly
+ // looks for code trying to introspect into tagged pointers, which
+ // code should generally never do.
+ if (ObjCPointerExpr && isa<IntegerLiteral>(OtherExpr->IgnoreParenCasts())) {
+ S.Diag(OpLoc, diag::warn_objc_pointer_masking)
+ << ObjCPointerExpr->getSourceRange();
+ }
+}
+
/// CreateBuiltinBinOp - Creates a new built-in binary operation with
/// operator @p Opc at location @c TokLoc. This routine only supports
/// built-in operations; ActOnBinOp handles overloaded operators.
@@ -8636,6 +8666,7 @@
ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc, false);
break;
case BO_And:
+ checkObjCPointerIntrospection(*this, LHS, RHS, OpLoc);
case BO_Xor:
case BO_Or:
ResultTy = CheckBitwiseOperands(LHS, RHS, OpLoc);
