NFC: simplify code in BuildInstanceMessage.

Instead of searching the global pool multiple times: in
LookupFactoryMethodInGlobalPool, LookupInstanceMethodInGlobalPool,
CollectMultipleMethodsInGlobalPool, and AreMultipleMethodsInGlobalPool,
we now collect the method candidates in CollectMultipleMethodsInGlobalPool
only, and other functions will use the collected method set.

This commit adds parameter "Methods" to AreMultipleMethodsInGlobalPool,
and SelectBestMethod. It also changes the implementation of
CollectMultipleMethodsInGlobalPool to collect the desired kind first, if none is
found, to collect the other kind. This avoids the need to call both
LookupFactoryMethodInGlobalPool and LookupInstanceMethodInGlobalPool.

llvm-svn: 265711

3 files changed, 94 insertions, 57 deletions

diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index b62f9130bdb..8ba3e7acec2 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -3281,25 +3281,57 @@ static bool isAcceptableMethodMismatch(ObjCMethodDecl *chosen,
   return (chosen->getReturnType()->isIntegerType());
 }
 
+/// We first select the type of the method: Instance or Factory, then collect
+/// all methods with that type.
 bool Sema::CollectMultipleMethodsInGlobalPool(
-    Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods, bool instance) {
+    Selector Sel, SmallVectorImpl<ObjCMethodDecl *> &Methods,
+    bool InstanceFirst, bool CheckTheOther) {
   if (ExternalSource)
     ReadMethodPool(Sel);
 
   GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
   if (Pos == MethodPool.end())
     return false;
+
   // Gather the non-hidden methods.
-  ObjCMethodList &MethList = instance ? Pos->second.first : Pos->second.second;
+  ObjCMethodList &MethList = InstanceFirst ? Pos->second.first :
+                             Pos->second.second;
   for (ObjCMethodList *M = &MethList; M; M = M->getNext())
     if (M->getMethod() && !M->getMethod()->isHidden())
       Methods.push_back(M->getMethod());
+
+  // Return if we find any method with the desired kind.
+  if (!Methods.empty())
+    return Methods.size() > 1;
+
+  if (!CheckTheOther)
+    return false;
+
+  // Gather the other kind.
+  ObjCMethodList &MethList2 = InstanceFirst ? Pos->second.second :
+                              Pos->second.first;
+  for (ObjCMethodList *M = &MethList2; M; M = M->getNext())
+    if (M->getMethod() && !M->getMethod()->isHidden())
+      Methods.push_back(M->getMethod());
+
   return Methods.size() > 1;
 }
 
-bool Sema::AreMultipleMethodsInGlobalPool(Selector Sel, ObjCMethodDecl *BestMethod,
-                                          SourceRange R,
-                                          bool receiverIdOrClass) {
+bool Sema::AreMultipleMethodsInGlobalPool(
+    Selector Sel, ObjCMethodDecl *BestMethod, SourceRange R,
+    bool receiverIdOrClass, SmallVectorImpl<ObjCMethodDecl *> &Methods) {
+  // Diagnose finding more than one method in global pool.
+  SmallVector<ObjCMethodDecl *, 4> FilteredMethods;
+  FilteredMethods.push_back(BestMethod);
+
+  for (auto *M : Methods)
+    if (M != BestMethod && !M->hasAttr<UnavailableAttr>())
+      FilteredMethods.push_back(M);
+
+  if (FilteredMethods.size() > 1)
+    DiagnoseMultipleMethodInGlobalPool(FilteredMethods, Sel, R,
+                                       receiverIdOrClass);
+
   GlobalMethodPool::iterator Pos = MethodPool.find(Sel);
   // Test for no method in the pool which should not trigger any warning by
   // caller.
@@ -3307,17 +3339,6 @@ bool Sema::AreMultipleMethodsInGlobalPool(Selector Sel, ObjCMethodDecl *BestMeth
     return true;
   ObjCMethodList &MethList =
     BestMethod->isInstanceMethod() ? Pos->second.first : Pos->second.second;
-  
-  // Diagnose finding more than one method in global pool
-  SmallVector<ObjCMethodDecl *, 4> Methods;
-  Methods.push_back(BestMethod);
-  for (ObjCMethodList *ML = &MethList; ML; ML = ML->getNext())
-    if (ObjCMethodDecl *M = ML->getMethod())
-      if (!M->isHidden() && M != BestMethod && !M->hasAttr<UnavailableAttr>())
-        Methods.push_back(M);
-  if (Methods.size() > 1)
-    DiagnoseMultipleMethodInGlobalPool(Methods, Sel, R, receiverIdOrClass);
-
   return MethList.hasMoreThanOneDecl();
 }
 
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 68f9235b074..7a51e612af8 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -2625,22 +2625,22 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
                                                                      typeBound);
     if (receiverIsIdLike || ReceiverType->isBlockPointerType() ||
         (Receiver && Context.isObjCNSObjectType(Receiver->getType()))) {
-      Method = LookupInstanceMethodInGlobalPool(Sel, 
-                                                SourceRange(LBracLoc, RBracLoc),
-                                                receiverIsIdLike);
-      if (!Method)
-        Method = LookupFactoryMethodInGlobalPool(Sel, 
-                                                 SourceRange(LBracLoc,RBracLoc),
-                                                 receiverIsIdLike);
-      if (Method) {
+      SmallVector<ObjCMethodDecl*, 4> Methods;
+      CollectMultipleMethodsInGlobalPool(Sel, Methods, true/*InstanceFirst*/,
+                                         true/*CheckTheOther*/);
+      if (!Methods.empty()) {
+        // We chose the first method as the initial condidate, then try to
+        // select a better one.
+        Method = Methods[0];
+
         if (ObjCMethodDecl *BestMethod =
-              SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod()))
+            SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(), Methods))
           Method = BestMethod;
+
         if (!AreMultipleMethodsInGlobalPool(Sel, Method,
                                             SourceRange(LBracLoc, RBracLoc),
-                                            receiverIsIdLike)) {
-          DiagnoseUseOfDecl(Method, SelLoc);
-        }
+                                            receiverIsIdLike, Methods))
+           DiagnoseUseOfDecl(Method, SelLoc);
       }
     } else if (ReceiverType->isObjCClassOrClassKindOfType() ||
                ReceiverType->isObjCQualifiedClassType()) {
@@ -2678,25 +2678,32 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
         if (!Method) {
           // If not messaging 'self', look for any factory method named 'Sel'.
           if (!Receiver || !isSelfExpr(Receiver)) {
-            Method = LookupFactoryMethodInGlobalPool(Sel, 
-                                                SourceRange(LBracLoc, RBracLoc));
-            if (!Method) {
-              // If no class (factory) method was found, check if an _instance_
-              // method of the same name exists in the root class only.
-              Method = LookupInstanceMethodInGlobalPool(Sel,
-                                               SourceRange(LBracLoc, RBracLoc));
-              if (Method)
-                  if (const ObjCInterfaceDecl *ID =
-                      dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
-                    if (ID->getSuperClass())
-                      Diag(SelLoc, diag::warn_root_inst_method_not_found)
-                      << Sel << SourceRange(LBracLoc, RBracLoc);
-                  }
+            // If no class (factory) method was found, check if an _instance_
+            // method of the same name exists in the root class only.
+            SmallVector<ObjCMethodDecl*, 4> Methods;
+            CollectMultipleMethodsInGlobalPool(Sel, Methods,
+                                               false/*InstanceFirst*/,
+                                               true/*CheckTheOther*/);
+            if (!Methods.empty()) {
+              // We chose the first method as the initial condidate, then try
+              // to select a better one.
+              Method = Methods[0];
+
+              // If we find an instance method, emit waring.
+              if (Method->isInstanceMethod()) {
+                if (const ObjCInterfaceDecl *ID =
+                    dyn_cast<ObjCInterfaceDecl>(Method->getDeclContext())) {
+                  if (ID->getSuperClass())
+                    Diag(SelLoc, diag::warn_root_inst_method_not_found)
+                        << Sel << SourceRange(LBracLoc, RBracLoc);
+                }
+              }
+
+             if (ObjCMethodDecl *BestMethod =
+                 SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
+                                  Methods))
+               Method = BestMethod;
             }
-            if (Method)
-              if (ObjCMethodDecl *BestMethod =
-                  SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod()))
-                Method = BestMethod;
           }
         }
       }
@@ -2761,15 +2768,24 @@ ExprResult Sema::BuildInstanceMessage(Expr *Receiver,
             // behavior isn't very desirable, however we need it for GCC
             // compatibility. FIXME: should we deviate??
             if (OCIType->qual_empty()) {
-              Method = LookupInstanceMethodInGlobalPool(Sel,
-                                              SourceRange(LBracLoc, RBracLoc));
-              if (Method) {
-                if (auto BestMethod =
-                      SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod()))
+              SmallVector<ObjCMethodDecl*, 4> Methods;
+              CollectMultipleMethodsInGlobalPool(Sel, Methods,
+                                                 true/*InstanceFirst*/,
+                                                 false/*CheckTheOther*/);
+              if (!Methods.empty()) {
+                // We chose the first method as the initial condidate, then try
+                // to select a better one.
+                Method = Methods[0];
+
+                if (ObjCMethodDecl *BestMethod =
+                    SelectBestMethod(Sel, ArgsIn, Method->isInstanceMethod(),
+                                     Methods))
                   Method = BestMethod;
+
                 AreMultipleMethodsInGlobalPool(Sel, Method,
                                                SourceRange(LBracLoc, RBracLoc),
-                                               true);
+                                               true/*receiverIdOrClass*/,
+                                               Methods);
               }
               if (Method && !forwardClass)
                 Diag(SelLoc, diag::warn_maynot_respond)
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 5b2ed0d8e43..0790dd15e13 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -5856,12 +5856,12 @@ Sema::AddOverloadCandidate(FunctionDecl *Function,
   }
 }
 
-ObjCMethodDecl *Sema::SelectBestMethod(Selector Sel, MultiExprArg Args,
-                                       bool IsInstance) {
-  SmallVector<ObjCMethodDecl*, 4> Methods;
-  if (!CollectMultipleMethodsInGlobalPool(Sel, Methods, IsInstance))
+ObjCMethodDecl *
+Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
+                       SmallVectorImpl<ObjCMethodDecl *> &Methods) {
+  if (Methods.size() <= 1)
     return nullptr;
-    
+
   for (unsigned b = 0, e = Methods.size(); b < e; b++) {
     bool Match = true;
     ObjCMethodDecl *Method = Methods[b];