objective-C: introduce __attribute((objc_requires_super)) on method

in classes. Use it to flag those method implementations which don't
contain call to 'super' if they have 'super' class and it has the method
with this attribute set. This is wip. // rdar://6386358


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163434 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 94 insertions, 8 deletions

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index fade83ef93..7406ce2647 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -528,6 +528,11 @@ def ObjCReturnsInnerPointer : Attr {
   let Subjects = [ObjCMethod];
 }
 
+def ObjCRequiresSuper : InheritableAttr {
+  let Spellings = [GNU<"objc_requires_super">];
+  let Subjects = [ObjCMethod];
+}
+
 def ObjCRootClass : Attr {
   let Spellings = [GNU<"objc_root_class">];
   let Subjects = [ObjCInterface];
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 75c98b1159..2b6cb4c34e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -740,7 +740,7 @@ def warn_objc_property_attr_mutually_exclusive : Warning<
   "property attributes '%0' and '%1' are mutually exclusive">,
   InGroup<ReadOnlySetterAttrs>, DefaultIgnore;
 def warn_objc_missing_super_dealloc : Warning<
-  "method possibly missing a [super dealloc] call">,
+  "method possibly missing a [super %0] call">,
   InGroup<ObjCMissingSuperCalls>;
 def error_dealloc_bad_result_type : Error<
   "dealloc return type must be correctly specified as 'void' under ARC, "
@@ -2057,6 +2057,12 @@ def warn_ns_attribute_wrong_parameter_type : Warning<
   "%0 attribute only applies to %select{Objective-C object|pointer}1 "
   "parameters">,
   InGroup<IgnoredAttributes>;
+def warn_objc_requires_super_protocol : Warning<
+  "%0 attribute cannot be applied to %select{methods in protocols|dealloc}1">,
+  InGroup<DiagGroup<"requires-super-attribute">>;
+def note_protocol_decl : Note<
+  "protocol is declared here">;
+
 def err_ns_bridged_not_interface : Error<
   "parameter of 'ns_bridged' attribute does not name an Objective-C class">;
 
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index b3db840397..5ed06d6daa 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -7832,7 +7832,8 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
         computeNRVO(Body, getCurFunction());
     }
     if (getCurFunction()->ObjCShouldCallSuperDealloc) {
-      Diag(MD->getLocEnd(), diag::warn_objc_missing_super_dealloc);
+      Diag(MD->getLocEnd(), diag::warn_objc_missing_super_dealloc)
+        << MD->getDeclName();
       getCurFunction()->ObjCShouldCallSuperDealloc = false;
     }
     if (getCurFunction()->ObjCShouldCallSuperFinalize) {
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 8ffffab8b5..119ce7dfff 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -3974,6 +3974,33 @@ static void handleObjCReturnsInnerPointerAttr(Sema &S, Decl *D,
     ::new (S.Context) ObjCReturnsInnerPointerAttr(attr.getRange(), S.Context));
 }
 
+static void handleObjCRequiresSuperAttr(Sema &S, Decl *D,
+                                        const AttributeList &attr) {
+  SourceLocation loc = attr.getLoc();
+  ObjCMethodDecl *method = dyn_cast<ObjCMethodDecl>(D);
+  
+  if (!method) {
+   S.Diag(D->getLocStart(), diag::err_attribute_wrong_decl_type)
+   << SourceRange(loc, loc) << attr.getName() << ExpectedMethod;
+    return;
+  }
+  DeclContext *DC = method->getDeclContext();
+  if (const ObjCProtocolDecl *PDecl = dyn_cast_or_null<ObjCProtocolDecl>(DC)) {
+    S.Diag(D->getLocStart(), diag::warn_objc_requires_super_protocol)
+    << attr.getName() << 0;
+    S.Diag(PDecl->getLocation(), diag::note_protocol_decl);
+    return;
+  }
+  if (method->getMethodFamily() == OMF_dealloc) {
+    S.Diag(D->getLocStart(), diag::warn_objc_requires_super_protocol)
+    << attr.getName() << 1;
+    return;
+  }
+  
+  method->addAttr(
+    ::new (S.Context) ObjCRequiresSuperAttr(attr.getRange(), S.Context));
+}
+
 /// Handle cf_audited_transfer and cf_unknown_transfer.
 static void handleCFTransferAttr(Sema &S, Decl *D, const AttributeList &A) {
   if (!isa<FunctionDecl>(D)) {
@@ -4281,6 +4308,9 @@ static void ProcessInheritableDeclAttr(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_ObjCReturnsInnerPointer:
     handleObjCReturnsInnerPointerAttr(S, D, Attr); break;
 
+  case AttributeList::AT_ObjCRequiresSuper:
+      handleObjCRequiresSuperAttr(S, D, Attr); break;
+      
   case AttributeList::AT_NSBridged:
     handleNSBridgedAttr(S, scope, D, Attr); break;
 
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index e800a6a7a4..709a868582 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -371,8 +371,10 @@ void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
   // Warn on deprecated methods under -Wdeprecated-implementations,
   // and prepare for warning on missing super calls.
   if (ObjCInterfaceDecl *IC = MDecl->getClassInterface()) {
-    if (ObjCMethodDecl *IMD = 
-          IC->lookupMethod(MDecl->getSelector(), MDecl->isInstanceMethod()))
+    ObjCMethodDecl *IMD = 
+      IC->lookupMethod(MDecl->getSelector(), MDecl->isInstanceMethod());
+    
+    if (IMD)
       DiagnoseObjCImplementedDeprecations(*this, 
                                           dyn_cast<NamedDecl>(IMD), 
                                           MDecl->getLocation(), 0);
@@ -385,7 +387,10 @@ void Sema::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
       getCurFunction()->ObjCShouldCallSuperDealloc = 
         !(Context.getLangOpts().ObjCAutoRefCount ||
           Context.getLangOpts().getGC() == LangOptions::GCOnly) &&
-        MDecl->getMethodFamily() == OMF_dealloc;
+          MDecl->getMethodFamily() == OMF_dealloc;
+      if (!getCurFunction()->ObjCShouldCallSuperDealloc)
+        getCurFunction()->ObjCShouldCallSuperDealloc = 
+          (IMD && IMD->hasAttr<ObjCRequiresSuperAttr>());
       getCurFunction()->ObjCShouldCallSuperFinalize =
         Context.getLangOpts().getGC() != LangOptions::NonGC &&
         MDecl->getMethodFamily() == OMF_finalize;
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index 17850bb2d7..58e28a9404 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1780,6 +1780,14 @@ ExprResult Sema::ActOnSuperMessage(Scope *S,
   if (Method->isInstanceMethod()) {
     if (Sel.getMethodFamily() == OMF_dealloc)
       getCurFunction()->ObjCShouldCallSuperDealloc = false;
+    else if (const ObjCMethodDecl *IMD =
+               Class->lookupMethod(Method->getSelector(), 
+                                   Method->isInstanceMethod()))
+          // Must check for name of message since the method could
+          // be another method with objc_requires_super attribute set.
+          if (IMD->hasAttr<ObjCRequiresSuperAttr>() && 
+              Sel == IMD->getSelector())
+            getCurFunction()->ObjCShouldCallSuperDealloc = false;
     if (Sel.getMethodFamily() == OMF_finalize)
       getCurFunction()->ObjCShouldCallSuperFinalize = false;
 
diff --git a/test/SemaObjC/super-dealloc-attribute.m b/test/SemaObjC/super-dealloc-attribute.m
new file mode 100644
index 0000000000..c2da8e92af
--- /dev/null
+++ b/test/SemaObjC/super-dealloc-attribute.m
@@ -0,0 +1,31 @@
+// RUN: %clang_cc1  -fsyntax-only -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1  -fsyntax-only -fobjc-arc -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -x objective-c++ -fobjc-arc -fsyntax-only -verify -Wno-objc-root-class %s
+
+// rdar://6386358
+@protocol NSObject // expected-note {{protocol is declared here}}
+- MyDealloc __attribute((objc_requires_super)); // expected-warning {{'objc_requires_super' attribute cannot be applied to methods in protocols}}
+@end
+
+@interface Root
+- MyDealloc __attribute((objc_requires_super));
+- (void)XXX __attribute((objc_requires_super));
+- (void) dealloc __attribute((objc_requires_super)); // expected-warning {{'objc_requires_super' attribute cannot be applied to dealloc}}
+@end
+
+@interface Baz : Root<NSObject>
+- MyDealloc;
+@end
+
+@implementation Baz
+-  MyDealloc {
+   [super MyDealloc];
+        return 0;
+}
+
+- (void)XXX {
+  [super MyDealloc];
+} // expected-warning {{method possibly missing a [super 'XXX'] call}}
+@end
+
diff --git a/test/SemaObjC/warn-missing-super.m b/test/SemaObjC/warn-missing-super.m
index 02b81651d7..ba65ec8c8d 100644
--- a/test/SemaObjC/warn-missing-super.m
+++ b/test/SemaObjC/warn-missing-super.m
@@ -41,11 +41,11 @@ __attribute__((objc_root_class))
 @end
 
 // RUN: %clang_cc1 -fsyntax-only %s 2>&1 | FileCheck %s
-// CHECK: warn-missing-super.m:24:1: warning: method possibly missing a [super dealloc] call
+// CHECK: warn-missing-super.m:24:1: warning: method possibly missing a [super 'dealloc'] call
 // CHECK: 1 warning generated.
 
 // RUN: %clang_cc1 -fsyntax-only -fobjc-gc %s 2>&1 | FileCheck --check-prefix=CHECK-GC %s
-// CHECK-GC: warn-missing-super.m:24:1: warning: method possibly missing a [super dealloc] call
+// CHECK-GC: warn-missing-super.m:24:1: warning: method possibly missing a [super 'dealloc'] call
 // CHECK-GC: warn-missing-super.m:26:1: warning: method possibly missing a [super finalize] call
 // CHECK-GC: 2 warnings generated.
 
diff --git a/test/SemaObjCXX/warn-missing-super.mm b/test/SemaObjCXX/warn-missing-super.mm
index cd2a6cca76..7383781535 100644
--- a/test/SemaObjCXX/warn-missing-super.mm
+++ b/test/SemaObjCXX/warn-missing-super.mm
@@ -15,5 +15,5 @@ template<typename T> struct shared_ptr {
 - (void)dealloc
 {
 	constexpr shared_ptr<int> dummy;
-} // expected-warning {{method possibly missing a [super dealloc] call}}
+} // expected-warning {{method possibly missing a [super 'dealloc'] call}}
 @end