After some discussion, conservatively extend our sentinel check to discard

casts, but still require the (casted) type to be a pointer.  Fixes PR5685.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103216 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rjmccall

lib/Sema/SemaExpr.cpp

@@ -160,16 +160,19 @@ void Sema::DiagnoseSentinelCalls(NamedDecl *D, SourceLocation Loc,
     ++sentinel;
   }
   Expr *sentinelExpr = Args[sentinel];
-  if (sentinelExpr && (!isa<GNUNullExpr>(sentinelExpr) &&
-                       !sentinelExpr->isTypeDependent() &&
-                       !sentinelExpr->isValueDependent() &&
-                       (!sentinelExpr->getType()->isPointerType() ||
-                        !sentinelExpr->isNullPointerConstant(Context,
-                                            Expr::NPC_ValueDependentIsNull)))) {
-    Diag(Loc, diag::warn_missing_sentinel) << isMethod;
-    Diag(D->getLocation(), diag::note_sentinel_here) << isMethod;
-  }
-  return;
+  if (!sentinelExpr) return;
+  if (sentinelExpr->isTypeDependent()) return;
+  if (sentinelExpr->isValueDependent()) return;
+  if (sentinelExpr->getType()->isPointerType() &&
+      sentinelExpr->IgnoreParenCasts()->isNullPointerConstant(Context,
+                                            Expr::NPC_ValueDependentIsNull))
+    return;
+
+  // Unfortunately, __null has type 'int'.
+  if (isa<GNUNullExpr>(sentinelExpr)) return;
+
+  Diag(Loc, diag::warn_missing_sentinel) << isMethod;
+  Diag(D->getLocation(), diag::note_sentinel_here) << isMethod;
 }
 
 SourceRange Sema::getExprRange(ExprTy *E) const {

test/Sema/attr-sentinel.c

@@ -4,7 +4,7 @@
 
 #define ATTR __attribute__ ((__sentinel__)) 
 
-void foo1 (int x, ...) ATTR; // expected-note {{function has been explicitly marked sentinel here}}
+void foo1 (int x, ...) ATTR; // expected-note 2 {{function has been explicitly marked sentinel here}}
 void foo5 (int x, ...) __attribute__ ((__sentinel__(1))); // expected-note {{function has been explicitly marked sentinel here}}
 void foo6 (int x, ...) __attribute__ ((__sentinel__(5))); // expected-note {{function has been explicitly marked sentinel here}}
 void foo7 (int x, ...) __attribute__ ((__sentinel__(0))); // expected-note {{function has been explicitly marked sentinel here}}
@@ -24,6 +24,12 @@ void test1() {
   foo7(1, NULL); // OK
 
   foo12(1); // expected-warning {{not enough variable arguments in 'foo12' declaration to fit a sentinel}}
+
+  // PR 5685
+  struct A {};
+  struct A a, b, c;
+  foo1(3, &a, &b, &c); // expected-warning {{missing sentinel in function call}}
+  foo1(3, &a, &b, &c, (struct A*) 0);
 }