r351509 - [analyzer] [RetainCountChecker] Produce a correct message when OSTypeAlloc is used

[George Karpenkov via cfe-commits]

Author: george.karpenkov
Date: Thu Jan 17 19:12:48 2019
New Revision: 351509

URL: http://llvm.org/viewvc/llvm-project?rev=351509&view=rev
Log:
[analyzer] [RetainCountChecker] Produce a correct message when OSTypeAlloc is used

Differential Revision: https://reviews.llvm.org/D56820

Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp
    cfe/trunk/test/Analysis/os_object_base.h
    cfe/trunk/test/Analysis/osobject-retain-release.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp?rev=351509&r1=351508&r2=351509&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp Thu Jan 17 19:12:48 2019
@@ -132,6 +132,32 @@ static Optional<unsigned> findArgIdxOfSy
   return None;
 }
 
+Optional<std::string> findMetaClassAlloc(const Expr *Callee) {
+  if (const auto *ME = dyn_cast<MemberExpr>(Callee)) {
+    if (ME->getMemberDecl()->getNameAsString() != "alloc")
+      return None;
+    const Expr *This = ME->getBase()->IgnoreParenImpCasts();
+    if (const auto *DRE = dyn_cast<DeclRefExpr>(This)) {
+      const ValueDecl *VD = DRE->getDecl();
+      if (VD->getNameAsString() != "metaClass")
+        return None;
+
+      if (const auto *RD = dyn_cast<CXXRecordDecl>(VD->getDeclContext()))
+        return RD->getNameAsString();
+
+    }
+  }
+  return None;
+}
+
+std::string findAllocatedObjectName(const Stmt *S,
+                                    QualType QT) {
+  if (const auto *CE = dyn_cast<CallExpr>(S))
+    if (auto Out = findMetaClassAlloc(CE->getCallee()))
+      return *Out;
+  return getPrettyTypeName(QT);
+}
+
 static void generateDiagnosticsForCallLike(ProgramStateRef CurrSt,
                                            const LocationContext *LCtx,
                                            const RefVal &CurrV, SymbolRef &Sym,
@@ -189,7 +215,7 @@ static void generateDiagnosticsForCallLi
     os << "a Core Foundation object of type '"
        << Sym->getType().getAsString() << "' with a ";
   } else if (CurrV.getObjKind() == ObjKind::OS) {
-    os << "an OSObject of type '" << getPrettyTypeName(Sym->getType())
+    os << "an OSObject of type '" << findAllocatedObjectName(S, Sym->getType())
        << "' with a ";
   } else if (CurrV.getObjKind() == ObjKind::Generalized) {
     os << "an object of type '" << Sym->getType().getAsString()

Modified: cfe/trunk/test/Analysis/os_object_base.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/os_object_base.h?rev=351509&r1=351508&r2=351509&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/os_object_base.h (original)
+++ cfe/trunk/test/Analysis/os_object_base.h Thu Jan 17 19:12:48 2019
@@ -47,7 +47,7 @@ struct OSObject : public OSMetaClassBase
 };
 
 struct OSMetaClass : public OSMetaClassBase {
-  virtual OSObject * alloc();
+  virtual OSObject * alloc() const;
   virtual ~OSMetaClass(){}
 };
 

Modified: cfe/trunk/test/Analysis/osobject-retain-release.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/osobject-retain-release.cpp?rev=351509&r1=351508&r2=351509&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/osobject-retain-release.cpp (original)
+++ cfe/trunk/test/Analysis/osobject-retain-release.cpp Thu Jan 17 19:12:48 2019
@@ -627,3 +627,10 @@ void test_smart_ptr_no_leak() {
   }
   obj->release();
 }
+
+void test_ostypealloc_correct_diagnostic_name() {
+  OSArray *arr = OSTypeAlloc(OSArray); // expected-note{{Call to method 'OSMetaClass::alloc' returns an OSObject of type 'OSArray' with a +1 retain count}}
+  arr->retain(); // expected-note{{Reference count incremented. The object now has a +2 retain count}}
+  arr->release(); // expected-note{{Reference count decremented. The object now has a +1 retain count}}
+} // expected-note{{Object leaked: object allocated and stored into 'arr' is not referenced later in this execution path and has a retain count of +1}}
+  // expected-warning at -1{{Potential leak of an object stored into 'arr'}}