From 83fb536ff98a65d4034d8b1cfd9b1b45a5950594 Mon Sep 17 00:00:00 2001
From: George Karpenkov <ekarpenkov@apple.com>
Date: Wed, 31 Oct 2018 17:38:46 +0000
Subject: [PATCH] [analyzer] Re-add custom OSIterator rule for
 RetainCountChecker

Turns out the rule is quite ubiquitous.

Revert of https://reviews.llvm.org/D53628

llvm-svn: 345747
---
 clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp | 13 +++++++++----
 clang/test/Analysis/osobject-retain-release.cpp        | 10 ++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp b/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
index b0e26ba..2fb0d75 100644
--- a/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
@@ -69,6 +69,10 @@ static bool isOSObjectDynamicCast(StringRef S) {
   return S == "safeMetaCast";
 }
 
+static bool isOSIteratorSubclass(const Decl *D) {
+  return isSubclass(D, "OSIterator");
+}
+
 static bool hasRCAnnotation(const Decl *D, StringRef rcAnnotation) {
   for (const auto *Ann : D->specific_attrs<AnnotateAttr>()) {
     if (Ann->getAnnotation() == rcAnnotation)
@@ -235,11 +239,12 @@ RetainSummaryManager::generateSummary(const FunctionDecl *FD,
         if (isOSObjectDynamicCast(II->getName()))
           return getDefaultSummary();
 
-        // All objects returned with functions starting with "get" are getters.
-        if (II->getName().startswith("get")) {
-          return getOSSummaryGetRule(FD);
-        } else {
+        // All objects returned with functions *not* starting with
+        // get, or iterators, are returned at +1.
+        if (!II->getName().startswith("get") || isOSIteratorSubclass(PD)) {
           return getOSSummaryCreateRule(FD);
+        } else {
+          return getOSSummaryGetRule(FD);
         }
       }
     }
diff --git a/clang/test/Analysis/osobject-retain-release.cpp b/clang/test/Analysis/osobject-retain-release.cpp
index 47601b0..71f9129 100644
--- a/clang/test/Analysis/osobject-retain-release.cpp
+++ b/clang/test/Analysis/osobject-retain-release.cpp
@@ -23,6 +23,9 @@ struct OSObject {
   static const OSMetaClass * const metaClass;
 };
 
+struct OSIterator : public OSObject {
+};
+
 struct OSArray : public OSObject {
   unsigned int getCount();
 
@@ -33,6 +36,8 @@ struct OSArray : public OSObject {
     return nullptr;
   }
 
+  OSIterator * getIterator();
+
   static OS_RETURNS_NOT_RETAINED OSArray *MaskedGetter();
   static OS_RETURNS_RETAINED OSArray *getOoopsActuallyCreate();
 
@@ -49,6 +54,11 @@ struct OSMetaClassBase {
   static OSObject *safeMetaCast(const OSObject *inst, const OSMetaClass *meta);
 };
 
+void check_custom_iterator_rule(OSArray *arr) {
+  OSIterator *it = arr->getIterator();
+  it->release();
+}
+
 void check_no_invalidation() {
   OSArray *arr = OSArray::withCapacity(10); // expected-note{{Call to function 'withCapacity' returns an OSObject of type struct OSArray * with a +1 retain count}}
   OtherStruct::doNothingToArray(arr);
-- 
2.7.4