r370773 - [LifetimeAnalysis] Fix some false positives
Gabor Horvath via cfe-commits
cfe-commits at lists.llvm.org
Tue Sep 3 09:17:24 PDT 2019
Author: xazax
Date: Tue Sep 3 09:17:24 2019
New Revision: 370773
URL: http://llvm.org/viewvc/llvm-project?rev=370773&view=rev
Log:
[LifetimeAnalysis] Fix some false positives
Differential Revision: https://reviews.llvm.org/D66806
Modified:
cfe/trunk/lib/Sema/SemaInit.cpp
cfe/trunk/test/Sema/warn-lifetime-analysis-nocfg.cpp
Modified: cfe/trunk/lib/Sema/SemaInit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=370773&r1=370772&r2=370773&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaInit.cpp (original)
+++ cfe/trunk/lib/Sema/SemaInit.cpp Tue Sep 3 09:17:24 2019
@@ -6775,6 +6775,10 @@ static bool shouldTrackFirstArgument(con
static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
LocalVisitor Visit) {
auto VisitPointerArg = [&](const Decl *D, Expr *Arg) {
+ // We are not interested in the temporary base objects of gsl Pointers:
+ // Temp().ptr; // Here ptr might not dangle.
+ if (isa<MemberExpr>(Arg->IgnoreImpCasts()))
+ return;
Path.push_back({IndirectLocalPathEntry::GslPointerInit, Arg, D});
if (Arg->isGLValue())
visitLocalsRetainedByReferenceBinding(Path, Arg, RK_ReferenceBinding,
@@ -7295,6 +7299,8 @@ static bool pathOnlyInitializesGslPointe
for (auto It = Path.rbegin(), End = Path.rend(); It != End; ++It) {
if (It->Kind == IndirectLocalPathEntry::VarInit)
continue;
+ if (It->Kind == IndirectLocalPathEntry::AddressOf)
+ continue;
return It->Kind == IndirectLocalPathEntry::GslPointerInit;
}
return false;
Modified: cfe/trunk/test/Sema/warn-lifetime-analysis-nocfg.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-lifetime-analysis-nocfg.cpp?rev=370773&r1=370772&r2=370773&view=diff
==============================================================================
--- cfe/trunk/test/Sema/warn-lifetime-analysis-nocfg.cpp (original)
+++ cfe/trunk/test/Sema/warn-lifetime-analysis-nocfg.cpp Tue Sep 3 09:17:24 2019
@@ -7,13 +7,21 @@ struct [[gsl::Owner(int)]] MyIntOwner {
struct [[gsl::Pointer(int)]] MyIntPointer {
MyIntPointer(int *p = nullptr);
// Conversion operator and constructor conversion will result in two
- // different ASTs. The former is tested with another owner and
+ // different ASTs. The former is tested with another owner and
// pointer type.
MyIntPointer(const MyIntOwner &);
int &operator*();
MyIntOwner toOwner();
};
+struct MySpecialIntPointer : MyIntPointer {
+};
+
+// We did see examples in the wild when a derived class changes
+// the ownership model. So we have a test for it.
+struct [[gsl::Owner(int)]] MyOwnerIntPointer : MyIntPointer {
+};
+
struct [[gsl::Pointer(long)]] MyLongPointerFromConversion {
MyLongPointerFromConversion(long *p = nullptr);
long &operator*();
@@ -56,21 +64,21 @@ struct Y {
};
void dangligGslPtrFromTemporary() {
- MyIntPointer p = Y{}.a; // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
+ MyIntPointer p = Y{}.a; // TODO
(void)p;
}
struct DanglingGslPtrField {
- MyIntPointer p; // expected-note 2{{pointer member declared here}}
+ MyIntPointer p; // expected-note {{pointer member declared here}}
MyLongPointerFromConversion p2; // expected-note {{pointer member declared here}}
- DanglingGslPtrField(int i) : p(&i) {} // expected-warning {{initializing pointer member 'p' with the stack address of parameter 'i'}}
+ DanglingGslPtrField(int i) : p(&i) {} // TODO
DanglingGslPtrField() : p2(MyLongOwnerWithConversion{}) {} // expected-warning {{initializing pointer member 'p2' to point to a temporary object whose lifetime is shorter than the lifetime of the constructed object}}
DanglingGslPtrField(double) : p(MyIntOwner{}) {} // expected-warning {{initializing pointer member 'p' to point to a temporary object whose lifetime is shorter than the lifetime of the constructed object}}
};
MyIntPointer danglingGslPtrFromLocal() {
int j;
- return &j; // expected-warning {{address of stack memory associated with local variable 'j' returned}}
+ return &j; // TODO
}
MyIntPointer returningLocalPointer() {
@@ -124,6 +132,7 @@ template <typename T>
struct basic_iterator {
basic_iterator operator++();
T& operator*() const;
+ T* operator->() const;
};
template<typename T>
@@ -141,6 +150,12 @@ typename remove_reference<T>::type &&mov
template <typename C>
auto data(const C &c) -> decltype(c.data());
+template <typename C>
+auto begin(C &c) -> decltype(c.begin());
+
+template<typename T, int N>
+T *begin(T (&array)[N]);
+
template <typename T>
struct vector {
typedef __gnu_cxx::basic_iterator<T> iterator;
@@ -158,6 +173,8 @@ struct basic_string_view {
template<typename T>
struct basic_string {
+ basic_string();
+ basic_string(const T *);
const T *c_str() const;
operator basic_string_view<T> () const;
};
@@ -188,8 +205,23 @@ struct any {};
template<typename T>
T any_cast(const any& operand);
+
+template<typename T>
+struct reference_wrapper {
+ template<typename U>
+ reference_wrapper(U &&);
+};
+
+template<typename T>
+reference_wrapper<T> ref(T& t) noexcept;
}
+struct Unannotated {
+ typedef std::vector<int>::iterator iterator;
+ iterator begin();
+ operator iterator() const;
+};
+
void modelIterators() {
std::vector<int>::iterator it = std::vector<int>().begin(); // expected-warning {{object backing the pointer will be destroyed at the end of the full-expression}}
(void)it;
@@ -298,3 +330,123 @@ void handleGslPtrInitsThroughReference2(
const std::vector<int> &v = getVec();
const int *val = v.data(); // Ok, it is lifetime extended.
}
+
+void handleTernaryOperator(bool cond) {
+ std::basic_string<char> def;
+ std::basic_string_view<char> v = cond ? def : ""; // expected-warning {{object backing the pointer will be destroyed at the end of the full-expression}}
+}
+
+std::reference_wrapper<int> danglingPtrFromNonOwnerLocal() {
+ int i = 5;
+ return i; // TODO
+}
+
+std::reference_wrapper<int> danglingPtrFromNonOwnerLocal2() {
+ int i = 5;
+ return std::ref(i); // TODO
+}
+
+std::reference_wrapper<int> danglingPtrFromNonOwnerLocal3() {
+ int i = 5;
+ return std::reference_wrapper<int>(i); // TODO
+}
+
+std::reference_wrapper<Unannotated> danglingPtrFromNonOwnerLocal4() {
+ Unannotated i;
+ return std::reference_wrapper<Unannotated>(i); // TODO
+}
+
+std::reference_wrapper<Unannotated> danglingPtrFromNonOwnerLocal5() {
+ Unannotated i;
+ return std::ref(i); // TODO
+}
+
+int *returnPtrToLocalArray() {
+ int a[5];
+ return std::begin(a); // TODO
+}
+
+struct ptr_wrapper {
+ std::vector<int>::iterator member;
+};
+
+ptr_wrapper getPtrWrapper();
+
+std::vector<int>::iterator returnPtrFromWrapper() {
+ ptr_wrapper local = getPtrWrapper();
+ return local.member;
+}
+
+std::vector<int>::iterator returnPtrFromWrapperThroughRef() {
+ ptr_wrapper local = getPtrWrapper();
+ ptr_wrapper &local2 = local;
+ return local2.member;
+}
+
+std::vector<int>::iterator returnPtrFromWrapperThroughRef2() {
+ ptr_wrapper local = getPtrWrapper();
+ std::vector<int>::iterator &local2 = local.member;
+ return local2;
+}
+
+void checkPtrMemberFromAggregate() {
+ std::vector<int>::iterator local = getPtrWrapper().member; // OK.
+}
+
+std::vector<int>::iterator doNotInterferWithUnannotated() {
+ Unannotated value;
+ // Conservative choice for now. Probably not ok, but we do not warn.
+ return std::begin(value);
+}
+
+std::vector<int>::iterator doNotInterferWithUnannotated2() {
+ Unannotated value;
+ return value;
+}
+
+std::vector<int>::iterator supportDerefAddrofChain(int a, std::vector<int>::iterator value) {
+ switch (a) {
+ default:
+ return value;
+ case 1:
+ return *&value;
+ case 2:
+ return *&*&value;
+ case 3:
+ return *&*&*&value;
+ }
+}
+
+int &supportDerefAddrofChain2(int a, std::vector<int>::iterator value) {
+ switch (a) {
+ default:
+ return *value;
+ case 1:
+ return **&value;
+ case 2:
+ return **&*&value;
+ case 3:
+ return **&*&*&value;
+ }
+}
+
+int *supportDerefAddrofChain3(int a, std::vector<int>::iterator value) {
+ switch (a) {
+ default:
+ return &*value;
+ case 1:
+ return &*&*value;
+ case 2:
+ return &*&**&value;
+ case 3:
+ return &*&**&*&value;
+ }
+}
+
+MyIntPointer handleDerivedToBaseCast1(MySpecialIntPointer ptr) {
+ return ptr;
+}
+
+MyIntPointer handleDerivedToBaseCast2(MyOwnerIntPointer ptr) {
+ return ptr; // expected-warning {{address of stack memory associated with parameter 'ptr' returned}}
+}
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