r319555 - Disallow a cleanup attribute from appertaining to a parameter (the attribute only appertains to local variables and is silently a noop on parameters). This repurposes the unused (and syntactically incorrect) NormalVar attribute subject.

[Aaron Ballman via cfe-commits]

Author: aaronballman
Date: Fri Dec  1 08:53:49 2017
New Revision: 319555

URL: http://llvm.org/viewvc/llvm-project?rev=319555&view=rev
Log:
Disallow a cleanup attribute from appertaining to a parameter (the attribute only appertains to local variables and is silently a noop on parameters). This repurposes the unused (and syntactically incorrect) NormalVar attribute subject.

Modified:
    cfe/trunk/include/clang/Basic/Attr.td
    cfe/trunk/lib/Sema/SemaDeclAttr.cpp
    cfe/trunk/test/Sema/attr-cleanup.c

Modified: cfe/trunk/include/clang/Basic/Attr.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=319555&r1=319554&r2=319555&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Attr.td (original)
+++ cfe/trunk/include/clang/Basic/Attr.td Fri Dec  1 08:53:49 2017
@@ -77,13 +77,8 @@ class SubsetSubject<AttrSubject base, co
   string DiagSpelling = diag;
 }
 
-// This is the type of a variable which C++11 allows alignas(...) to appertain
-// to.
-def NormalVar : SubsetSubject<Var,
-                              [{S->getStorageClass() != VarDecl::Register &&
-                                S->getKind() != Decl::ImplicitParam &&
-                                S->getKind() != Decl::ParmVar &&
-                                S->getKind() != Decl::NonTypeTemplateParm}],
+def LocalVar : SubsetSubject<Var,
+                              [{S->hasLocalStorage() && !isa<ParmVarDecl>(S)}],
                               "local variables">;
 def NonParmVar : SubsetSubject<Var,
                                [{S->getKind() != Decl::ParmVar}],
@@ -533,7 +528,6 @@ def Alias : Attr {
 def Aligned : InheritableAttr {
   let Spellings = [GCC<"aligned">, Declspec<"align">, Keyword<"alignas">,
                    Keyword<"_Alignas">];
-//  let Subjects = SubjectList<[NonBitField, NormalVar, Tag]>;
   let Args = [AlignedArgument<"Alignment", 1>];
   let Accessors = [Accessor<"isGNU", [GCC<"aligned">]>,
                    Accessor<"isC11", [Keyword<"_Alignas">]>,
@@ -768,7 +762,7 @@ def CFConsumed : InheritableParamAttr {
 def Cleanup : InheritableAttr {
   let Spellings = [GCC<"cleanup">];
   let Args = [FunctionArgument<"FunctionDecl">];
-  let Subjects = SubjectList<[Var]>;
+  let Subjects = SubjectList<[LocalVar]>;
   let Documentation = [Undocumented];
 }
 

Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=319555&r1=319554&r2=319555&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Fri Dec  1 08:53:49 2017
@@ -3067,12 +3067,6 @@ static void handleTargetAttr(Sema &S, De
 }
 
 static void handleCleanupAttr(Sema &S, Decl *D, const AttributeList &Attr) {
-  VarDecl *VD = cast<VarDecl>(D);
-  if (!VD->hasLocalStorage()) {
-    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << Attr.getName();
-    return;
-  }
-
   Expr *E = Attr.getArgAsExpr(0);
   SourceLocation Loc = E->getExprLoc();
   FunctionDecl *FD = nullptr;
@@ -3115,7 +3109,7 @@ static void handleCleanupAttr(Sema &S, D
 
   // We're currently more strict than GCC about what function types we accept.
   // If this ever proves to be a problem it should be easy to fix.
-  QualType Ty = S.Context.getPointerType(VD->getType());
+  QualType Ty = S.Context.getPointerType(cast<VarDecl>(D)->getType());
   QualType ParamTy = FD->getParamDecl(0)->getType();
   if (S.CheckAssignmentConstraints(FD->getParamDecl(0)->getLocation(),
                                    ParamTy, Ty) != Sema::Compatible) {

Modified: cfe/trunk/test/Sema/attr-cleanup.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-cleanup.c?rev=319555&r1=319554&r2=319555&view=diff
==============================================================================
--- cfe/trunk/test/Sema/attr-cleanup.c (original)
+++ cfe/trunk/test/Sema/attr-cleanup.c Fri Dec  1 08:53:49 2017
@@ -2,16 +2,16 @@
 
 void c1(int *a);
 
-extern int g1 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute ignored}}
-int g2 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute ignored}}
-static int g3 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute ignored}}
+extern int g1 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute only applies to local variables}}
+int g2 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute only applies to local variables}}
+static int g3 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute only applies to local variables}}
 
 void t1()
 {
     int v1 __attribute((cleanup)); // expected-error {{'cleanup' attribute takes one argument}}
     int v2 __attribute((cleanup(1, 2))); // expected-error {{'cleanup' attribute takes one argument}}
 
-    static int v3 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute ignored}}
+    static int v3 __attribute((cleanup(c1))); // expected-warning {{'cleanup' attribute only applies to local variables}}
 
     int v4 __attribute((cleanup(h))); // expected-error {{use of undeclared identifier 'h'}}
 
@@ -46,3 +46,5 @@ void t5() {
 void t6(void) {
   int i __attribute__((cleanup((void *)0)));  // expected-error {{'cleanup' argument is not a function}}
 }
+
+void t7(__attribute__((cleanup(c4))) int a) {} // expected-warning {{'cleanup' attribute only applies to local variables}}