dcoughlin created this revision.
dcoughlin added reviewers: zaks.anna, NoQ.
dcoughlin added a subscriber: cfe-commits.
Herald added a subscriber: aemerson.
The analyzer does not model C++ temporary destructors completely and so reports
false alarms about leaks of memory allocated by the internals of shared_ptr:
std::shared_ptr<int> p(new int(1));
p = nullptr; // 'Potential leak of memory pointed to by field __cntrl_'
To avoid these spurious diagnostics, this patch suppresses all diagnostics
where the end of the path is inside a method in std::shared_ptr.
rdar://problem/23652766
http://reviews.llvm.org/D22048
Files:
lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
test/Analysis/Inputs/system-header-simulator-cxx.h
test/Analysis/inlining/stl.cpp
Index: test/Analysis/inlining/stl.cpp
===================================================================
--- test/Analysis/inlining/stl.cpp
+++ test/Analysis/inlining/stl.cpp
@@ -52,3 +52,9 @@
void testSupprerssion_independent_bits_engine(MyEngine& e) {
std::__independent_bits_engine<MyEngine, unsigned int> x(e, 64); //
no-warning
}
+
+void testSuppression_std_shared_pointer() {
+ std::shared_ptr<int> p(new int(1));
+
+ p = nullptr; // no-warning
+}
Index: test/Analysis/Inputs/system-header-simulator-cxx.h
===================================================================
--- test/Analysis/Inputs/system-header-simulator-cxx.h
+++ test/Analysis/Inputs/system-header-simulator-cxx.h
@@ -329,6 +329,36 @@
z = 5/z;
}
+#if __has_feature(cxx_decltype)
+typedef decltype(nullptr) nullptr_t;
+
+template<class _Tp>
+class shared_ptr
+{
+public:
+ constexpr shared_ptr(nullptr_t);
+ explicit shared_ptr(_Tp* __p);
+
+ shared_ptr(shared_ptr&& __r) { }
+
+ ~shared_ptr();
+
+ shared_ptr& operator=(shared_ptr&& __r) {
+ // Fake error trigger.
+ // No warning is expected as we are suppressing warning coming
+ // out of std::basic_string.
+ int z = 0;
+ z = 5/z;
+ }
+};
+
+template<class _Tp>
+inline
+constexpr
+shared_ptr<_Tp>::shared_ptr(nullptr_t) {
+}
+
+#endif // __has_feature(cxx_decltype)
}
void* operator new(std::size_t, const std::nothrow_t&) throw();
Index: lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
===================================================================
--- lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -1596,23 +1596,31 @@
}
}
- // The analyzer issues a false positive on
- // std::basic_string<uint8_t> v; v.push_back(1);
- // and
- // std::u16string s; s += u'a';
- // because we cannot reason about the internal invariants of the
- // datastructure.
for (const LocationContext *LCtx = N->getLocationContext(); LCtx;
LCtx = LCtx->getParent()) {
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());
if (!MD)
continue;
const CXXRecordDecl *CD = MD->getParent();
+ // The analyzer issues a false positive on
+ // std::basic_string<uint8_t> v; v.push_back(1);
+ // and
+ // std::u16string s; s += u'a';
+ // because we cannot reason about the internal invariants of the
+ // datastructure.
if (CD->getName() == "basic_string") {
BR.markInvalid(getTag(), nullptr);
return nullptr;
}
+
+ // The analyzer issues a false positive on
+ // std::shared_ptr<int> p(new int(1)); p = nullptr;
+ // because it does not reason properly about temporary destructors.
+ if (CD->getName() == "shared_ptr") {
+ BR.markInvalid(getTag(), nullptr);
+ return nullptr;
+ }
}
}
}
Index: test/Analysis/inlining/stl.cpp
===================================================================
--- test/Analysis/inlining/stl.cpp
+++ test/Analysis/inlining/stl.cpp
@@ -52,3 +52,9 @@
void testSupprerssion_independent_bits_engine(MyEngine& e) {
std::__independent_bits_engine<MyEngine, unsigned int> x(e, 64); // no-warning
}
+
+void testSuppression_std_shared_pointer() {
+ std::shared_ptr<int> p(new int(1));
+
+ p = nullptr; // no-warning
+}
Index: test/Analysis/Inputs/system-header-simulator-cxx.h
===================================================================
--- test/Analysis/Inputs/system-header-simulator-cxx.h
+++ test/Analysis/Inputs/system-header-simulator-cxx.h
@@ -329,6 +329,36 @@
z = 5/z;
}
+#if __has_feature(cxx_decltype)
+typedef decltype(nullptr) nullptr_t;
+
+template<class _Tp>
+class shared_ptr
+{
+public:
+ constexpr shared_ptr(nullptr_t);
+ explicit shared_ptr(_Tp* __p);
+
+ shared_ptr(shared_ptr&& __r) { }
+
+ ~shared_ptr();
+
+ shared_ptr& operator=(shared_ptr&& __r) {
+ // Fake error trigger.
+ // No warning is expected as we are suppressing warning coming
+ // out of std::basic_string.
+ int z = 0;
+ z = 5/z;
+ }
+};
+
+template<class _Tp>
+inline
+constexpr
+shared_ptr<_Tp>::shared_ptr(nullptr_t) {
+}
+
+#endif // __has_feature(cxx_decltype)
}
void* operator new(std::size_t, const std::nothrow_t&) throw();
Index: lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
===================================================================
--- lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -1596,23 +1596,31 @@
}
}
- // The analyzer issues a false positive on
- // std::basic_string<uint8_t> v; v.push_back(1);
- // and
- // std::u16string s; s += u'a';
- // because we cannot reason about the internal invariants of the
- // datastructure.
for (const LocationContext *LCtx = N->getLocationContext(); LCtx;
LCtx = LCtx->getParent()) {
const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());
if (!MD)
continue;
const CXXRecordDecl *CD = MD->getParent();
+ // The analyzer issues a false positive on
+ // std::basic_string<uint8_t> v; v.push_back(1);
+ // and
+ // std::u16string s; s += u'a';
+ // because we cannot reason about the internal invariants of the
+ // datastructure.
if (CD->getName() == "basic_string") {
BR.markInvalid(getTag(), nullptr);
return nullptr;
}
+
+ // The analyzer issues a false positive on
+ // std::shared_ptr<int> p(new int(1)); p = nullptr;
+ // because it does not reason properly about temporary destructors.
+ if (CD->getName() == "shared_ptr") {
+ BR.markInvalid(getTag(), nullptr);
+ return nullptr;
+ }
}
}
}
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