ObjC kindof: check the context when inserting methods to global pool.

To make kindof lookup work, we need to insert methods with different
context into the global pool, even though they have the same siganture.

Since diagnosis of availability is performed on the best candidate,
which is often the first candidate from the global pool, we prioritize
the methods that are unavaible or deprecated to the head of the list.

Since we now have more methods in the global pool, we need to watch
out for performance impact.

rdar://25635831

llvm-svn: 265877

1 files changed, 38 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 32244e9e195..a9cc0d61be9 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -3167,6 +3167,26 @@ bool Sema::MatchTwoMethodDeclarations(const ObjCMethodDecl *left,
   return true;
 }
 
+static bool isMethodContextSameForKindofLookup(ObjCMethodDecl *Method,
+                                               ObjCMethodDecl *MethodInList) {
+  auto *MethodProtocol = dyn_cast<ObjCProtocolDecl>(Method->getDeclContext());
+  auto *MethodInListProtocol =
+      dyn_cast<ObjCProtocolDecl>(MethodInList->getDeclContext());
+  // If this method belongs to a protocol but the method in list does not, or
+  // vice versa, we say the context is not the same.
+  if ((MethodProtocol && !MethodInListProtocol) ||
+      (!MethodProtocol && MethodInListProtocol))
+    return false;
+
+  if (MethodProtocol && MethodInListProtocol)
+    return true;
+
+  ObjCInterfaceDecl *MethodInterface = Method->getClassInterface();
+  ObjCInterfaceDecl *MethodInListInterface =
+      MethodInList->getClassInterface();
+  return MethodInterface == MethodInListInterface;
+}
+
 void Sema::addMethodToGlobalList(ObjCMethodList *List,
                                  ObjCMethodDecl *Method) {
   // Record at the head of the list whether there were 0, 1, or >= 2 methods
@@ -3185,13 +3205,17 @@ void Sema::addMethodToGlobalList(ObjCMethodList *List,
 
   // We've seen a method with this name, see if we have already seen this type
   // signature.
+  ObjCMethodList *Head = List;
   ObjCMethodList *Previous = List;
   for (; List; Previous = List, List = List->getNext()) {
     // If we are building a module, keep all of the methods.
     if (getLangOpts().CompilingModule)
       continue;
 
-    if (!MatchTwoMethodDeclarations(Method, List->getMethod())) {
+    // Looking for method with a type bound requires the correct context exists.
+    // We need to insert this method into the list if the context is different.
+    if (!MatchTwoMethodDeclarations(Method, List->getMethod()) ||
+        !isMethodContextSameForKindofLookup(Method, List->getMethod())) {
       // Even if two method types do not match, we would like to say
       // there is more than one declaration so unavailability/deprecated
       // warning is not too noisy.
@@ -3232,6 +3256,19 @@ void Sema::addMethodToGlobalList(ObjCMethodList *List,
   // We have a new signature for an existing method - add it.
   // This is extremely rare. Only 1% of Cocoa selectors are "overloaded".
   ObjCMethodList *Mem = BumpAlloc.Allocate<ObjCMethodList>();
+
+  // We tried to prioritize the list by putting deprecated and unavailable
+  // methods in the front.
+  if ((Method->isDeprecated() && !Head->getMethod()->isDeprecated()) ||
+      (Method->isUnavailable() &&
+       Head->getMethod()->getAvailability() < AR_Deprecated)) {
+    auto *List = new (Mem) ObjCMethodList(*Head);
+    // FIXME: should we clear the other bits in Head?
+    Head->setMethod(Method);
+    Head->setNext(List);
+    return;
+  }
+
   Previous->setNext(new (Mem) ObjCMethodList(Method));
 }