From b0b61955a10f4289cbdee6c11ef284fad04a6a70 Mon Sep 17 00:00:00 2001
From: George Karpenkov <ekarpenkov@apple.com>
Date: Thu, 6 Dec 2018 22:07:12 +0000
Subject: [PATCH] [analyzer] Rely on os_consumes_this attribute to signify that
 the method call consumes a reference for "this"

Differential Revision: https://reviews.llvm.org/D55158

llvm-svn: 348533
---
 .../clang/StaticAnalyzer/Core/RetainSummaryManager.h     |  4 ++++
 clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp   |  3 +++
 clang/test/Analysis/osobject-retain-release.cpp          | 16 ++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h b/clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
index dfcbd0c..c2e9eaa 100644
--- a/clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
+++ b/clang/include/clang/StaticAnalyzer/Core/RetainSummaryManager.h
@@ -369,8 +369,12 @@ public:
   ///  This is only meaningful if the summary applies to an ObjCMessageExpr*.
   ArgEffect getReceiverEffect() const { return Receiver; }
 
+  /// \return the effect on the "this" receiver of the method call.
   ArgEffect getThisEffect() const { return This; }
 
+  /// Set the effect of the method on "this".
+  void setThisEffect(ArgEffect e) { This = e; }
+
   bool isNoop() const {
     return Ret == RetEffect::MakeNoRet() && Receiver == DoNothing
       && DefaultArgEffect == MayEscape && This == DoNothing
diff --git a/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp b/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
index 0e82d9a..67efa54 100644
--- a/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RetainSummaryManager.cpp
@@ -759,6 +759,9 @@ RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
   QualType RetTy = FD->getReturnType();
   if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD))
     Template->setRetEffect(*RetE);
+
+  if (FD->hasAttr<OSConsumesThisAttr>())
+    Template->setThisEffect(DecRef);
 }
 
 void
diff --git a/clang/test/Analysis/osobject-retain-release.cpp b/clang/test/Analysis/osobject-retain-release.cpp
index a596d0d..cf92e2d 100644
--- a/clang/test/Analysis/osobject-retain-release.cpp
+++ b/clang/test/Analysis/osobject-retain-release.cpp
@@ -5,6 +5,7 @@ struct OSMetaClass;
 #define OS_CONSUME __attribute__((os_consumed))
 #define OS_RETURNS_RETAINED __attribute__((os_returns_retained))
 #define OS_RETURNS_NOT_RETAINED __attribute__((os_returns_not_retained))
+#define OS_CONSUMES_THIS __attribute__((os_consumes_this))
 
 #define OSTypeID(type)   (type::metaClass)
 
@@ -49,6 +50,11 @@ struct OSArray : public OSObject {
 
   virtual void consumeReference(OS_CONSUME OSArray *other);
 
+  void putIntoArray(OSArray *array) OS_CONSUMES_THIS;
+
+  template <typename T>
+  void putIntoT(T *owner) OS_CONSUMES_THIS;
+
   static OSArray *generateArrayHasCode() {
     return new OSArray;
   }
@@ -112,6 +118,16 @@ unsigned int check_attribute_indirect_propagation(MyArray *arr) {
   return 0;
 }
 
+void check_consumes_this(OSArray *owner) {
+  OSArray *arr = new OSArray;
+  arr->putIntoArray(owner);
+}
+
+void check_consumes_this_with_template(OSArray *owner) {
+  OSArray *arr = new OSArray;
+  arr->putIntoT(owner);
+}
+
 void check_free_no_error() {
   OSArray *arr = OSArray::withCapacity(10);
   arr->retain();
-- 
2.7.4