Fix <rdar://problem/6191148> [sema] Objective-C method lookup (at global scope) fails to handle overloaded selectors properly.

Long standing bug in Sema::ActOnInstanceMessage(). We now warn when messaging an "id" with multiple method signatures in scope. The diags are a little verbose, however they can be streamlined if necessary. 


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@56843 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 28 insertions, 6 deletions

diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index dcd197dad6..49d69ad92d 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -379,6 +379,10 @@ private:
   /// messages sent to "id" (where the class of the object is unknown).
   void AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method);
   
+  /// LookupInstanceMethodInGlobalPool - Returns the method and warns if
+  /// there are multiple signatures.
+  ObjCMethodDecl *LookupInstanceMethodInGlobalPool(Selector Sel, SourceRange R);
+  
   /// AddFactoryMethodToGlobalPool - Same as above, but for factory methods.
   void AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method);
   //===--------------------------------------------------------------------===//
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index f98eeb6112..05c3bc78b3 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -776,6 +776,21 @@ void Sema::AddInstanceMethodToGlobalPool(ObjCMethodDecl *Method) {
   }
 }
 
+ObjCMethodDecl *Sema::LookupInstanceMethodInGlobalPool(Selector Sel, 
+                                                       SourceRange R) {
+  ObjCMethodList &MethList = InstanceMethodPool[Sel];
+  
+  if (MethList.Method && MethList.Next) {
+    Diag(R.getBegin(), diag::warn_multiple_method_decl, Sel.getName(), R);
+    Diag(MethList.Method->getLocStart(), diag::warn_using_decl, 
+         MethList.Method->getSourceRange());
+    for (ObjCMethodList *Next = MethList.Next; Next; Next = Next->Next)
+      Diag(Next->Method->getLocStart(), diag::warn_also_found_decl, 
+           Next->Method->getSourceRange());
+  }
+  return MethList.Method;
+}
+
 void Sema::AddFactoryMethodToGlobalPool(ObjCMethodDecl *Method) {
   ObjCMethodList &FirstMethod = FactoryMethodPool[Method->getSelector()];
   if (!FirstMethod.Method) {
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index db83405283..a474b7eee7 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -283,7 +283,8 @@ Sema::ExprResult Sema::ActOnInstanceMessage(ExprTy *receiver, Selector Sel,
   // Handle messages to id.
   if (ReceiverCType == Context.getCanonicalType(Context.getObjCIdType()) ||
       ReceiverCType->getAsBlockPointerType()) {
-    ObjCMethodDecl *Method = InstanceMethodPool[Sel].Method;
+    ObjCMethodDecl *Method = LookupInstanceMethodInGlobalPool(
+                               Sel, SourceRange(lbrac,rbrac));
     if (!Method)
       Method = FactoryMethodPool[Sel].Method;
     if (CheckMessageArgumentTypes(ArgExprs, NumArgs, Sel, Method, "-", 
@@ -306,7 +307,8 @@ Sema::ExprResult Sema::ActOnInstanceMessage(ExprTy *receiver, Selector Sel,
     if (!Method)
       Method = FactoryMethodPool[Sel].Method;
     if (!Method)
-      Method = InstanceMethodPool[Sel].Method;
+      Method = LookupInstanceMethodInGlobalPool(
+                               Sel, SourceRange(lbrac,rbrac));
     if (CheckMessageArgumentTypes(ArgExprs, NumArgs, Sel, Method, "-", 
                                   lbrac, rbrac, returnType))
       return true;
@@ -335,9 +337,9 @@ Sema::ExprResult Sema::ActOnInstanceMessage(ExprTy *receiver, Selector Sel,
     // We allow sending a message to a pointer to an interface (an object).
     
     ClassDecl = OCIReceiver->getDecl();
-    // FIXME: consider using InstanceMethodPool, since it will be faster
-    // than the following method (which can do *many* linear searches). The
-    // idea is to add class info to InstanceMethodPool.
+    // FIXME: consider using LookupInstanceMethodInGlobalPool, since it will be
+    // faster than the following method (which can do *many* linear searches). 
+    // The idea is to add class info to InstanceMethodPool.
     Method = ClassDecl->lookupInstanceMethod(Sel);
     
     if (!Method) {
@@ -369,7 +371,8 @@ Sema::ExprResult Sema::ActOnInstanceMessage(ExprTy *receiver, Selector Sel,
         // behavior isn't very desirable, however we need it for GCC
         // compatibility.
         if (!Method)
-          Method = InstanceMethodPool[Sel].Method;
+          Method = LookupInstanceMethodInGlobalPool(
+                               Sel, SourceRange(lbrac,rbrac));
   }
   if (CheckMessageArgumentTypes(ArgExprs, NumArgs, Sel, Method, "-", 
                                 lbrac, rbrac, returnType))