[PATCH] D77551: [analyzer] Fix NSErrorChecker false positives

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko created this revision.
vsavchenko added reviewers: NoQ, dcoughlin.
Herald added subscribers: cfe-commits, ASDenysPetrov, martong, Charusso, dkrupp, donat.nagy, Szelethus, mikhail.ramalho, a.sidorin, szepet, baloghadamsoftware, xazax.hun.
Herald added a project: clang.

NSErrorChecker used to suggest changing 'void' return type for
constructors and delete operators. This makes little sense because
return types of these functions could not be altered.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77551

Files:
  clang/lib/StaticAnalyzer/Checkers/NSErrorChecker.cpp
  clang/test/Analysis/SpecialFunctionsCFError.cpp


Index: clang/test/Analysis/SpecialFunctionsCFError.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/SpecialFunctionsCFError.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,osx.coreFoundation.CFError \
+// RUN:   -analyzer-store=region -verify %s
+
+typedef unsigned long size_t;
+struct __CFError {};
+typedef struct __CFError *CFErrorRef;
+void *malloc(size_t);
+
+class Foo {
+public:
+  Foo(CFErrorRef *error) {} // no-warning
+
+  void operator delete(void *pointer, CFErrorRef *error) { // no-warning
+    return;
+  }
+
+  void operator delete[](void *pointer, CFErrorRef *error) { // no-warning
+    return;
+  }
+
+  // Check that we report warnings for operators when it can be useful
+  void operator()(CFErrorRef *error) {} // expected-warning {{Function accepting CFErrorRef* should have a non-void return value to indicate whether or not an error occurred}}
+};
+
+// Check that global delete operator is not bothered as well
+void operator delete(void *pointer, CFErrorRef *error) { // no-warning
+  return;
+}
Index: clang/lib/StaticAnalyzer/Checkers/NSErrorChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/NSErrorChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/NSErrorChecker.cpp
@@ -95,6 +95,15 @@
 };
 }
 
+static bool hasReservedReturnType(const FunctionDecl *D) {
+  if (isa<CXXConstructorDecl>(D))
+    return true;
+
+  // operators delete and delete[] are required to have 'void' return type
+  auto OperatorKind = D->getOverloadedOperator();
+  return OperatorKind == OO_Delete || OperatorKind == OO_Array_Delete;
+}
+
 void CFErrorFunctionChecker::checkASTDecl(const FunctionDecl *D,
                                         AnalysisManager &mgr,
                                         BugReporter &BR) const {
@@ -102,6 +111,8 @@
     return;
   if (!D->getReturnType()->isVoidType())
     return;
+  if (hasReservedReturnType(D))
+    return;
 
   if (!II)
     II = &D->getASTContext().Idents.get("CFErrorRef");


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