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75873bb4a6
This adds a `NewOrNewArrayExpr.getPlacementPointer` predicate and uses it in `Alloc.qll` to detect when a `new`-expression is not an allocation. User-defined replacements for `operator new` may not be allocations either, but the code continues to assume that they are. It's possible that we want to change this assumption in the future or leave it up to individual queries to decide on which side to err. It's hard to statically tell whether `operator new` has been overloaded in a particular file because it can be overloaded by a definition that is not in scope but is only linked together with that file.
140 lines
3.9 KiB
C++
140 lines
3.9 KiB
C++
// semmle-extractor-options: -std=c++17
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typedef unsigned long size_t;
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namespace std {
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enum class align_val_t : size_t {};
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}
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void* operator new(size_t, float);
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void* operator new[](size_t, float);
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void* operator new(size_t, std::align_val_t, float);
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void* operator new[](size_t, std::align_val_t, float);
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void operator delete(void*, float);
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void operator delete[](void*, float);
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void operator delete(void*, std::align_val_t, float);
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void operator delete[](void*, std::align_val_t, float);
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struct String {
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String();
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String(const String&);
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String(String&&);
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String(const char*);
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~String();
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String& operator=(const String&);
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String& operator=(String&&);
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const char* c_str() const;
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private:
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const char* p;
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};
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struct SizedDealloc {
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char a[32];
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void* operator new(size_t);
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void* operator new[](size_t);
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void operator delete(void*, size_t);
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void operator delete[](void*, size_t);
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};
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struct alignas(128) Overaligned {
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char a[256];
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};
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struct PolymorphicBase {
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virtual ~PolymorphicBase();
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};
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void OperatorNew() {
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new int; // No constructor
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new(1.0f) int; // Placement new, no constructor
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new int(); // Zero-init
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new String(); // Constructor
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new(1.0f) String("hello"); // Placement new, constructor with args
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new Overaligned; // Aligned new
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new(1.0f) Overaligned(); // Placement aligned new
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}
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void OperatorDelete() {
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delete static_cast<int*>(nullptr); // No destructor
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delete static_cast<String*>(nullptr); // Non-virtual destructor, with size.
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delete static_cast<SizedDealloc*>(nullptr); // No destructor, with size.
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delete static_cast<Overaligned*>(nullptr); // No destructor, with size and alignment.
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delete static_cast<PolymorphicBase*>(nullptr); // Virtual destructor
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delete static_cast<const String*>(nullptr); // Pointer to const
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}
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void OperatorNewArray(int n) {
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new int[n]; // No constructor
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new(1.0f) int[n]; // Placement new, no constructor
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new String[n]; // Constructor
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new Overaligned[n]; // Aligned new
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new String[10]; // Constant size
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}
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int* const GetPointer();
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void OperatorDeleteArray() {
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delete[] static_cast<int*>(nullptr); // No destructor
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delete[] static_cast<String*>(nullptr); // Non-virtual destructor, with size.
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delete[] static_cast<SizedDealloc*>(nullptr); // No destructor, with size.
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delete[] static_cast<Overaligned*>(nullptr); // No destructor, with size and alignment.
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delete[] static_cast<PolymorphicBase*>(nullptr); // Virtual destructor
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delete[] GetPointer();
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}
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struct FailedInit {
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FailedInit();
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~FailedInit();
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void* operator new(size_t); // Non-placement
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void* operator new[](size_t); // Non-placement
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void operator delete(void*, size_t); // Sized deallocation
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void operator delete[](void*, size_t); // Sized deallocation
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};
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struct alignas(128) FailedInitOveraligned {
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FailedInitOveraligned();
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~FailedInitOveraligned();
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void* operator new(size_t, std::align_val_t, float); // Aligned placement
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void* operator new[](size_t, std::align_val_t, float); // Aligned placement
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void operator delete(void*, std::align_val_t, float); // Aligned placement
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void operator delete[](void*, std::align_val_t, float); // Aligned placement
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};
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void TestFailedInit(int n) {
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new FailedInit();
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new FailedInit[n];
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new(1.0f) FailedInitOveraligned();
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new(1.0f) FailedInitOveraligned[10];
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}
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// --- non-allocating placement new ---
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namespace std {
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typedef unsigned long size_t;
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struct nothrow_t {};
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extern const nothrow_t nothrow;
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}
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void* operator new (std::size_t size, void* ptr) noexcept;
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void* operator new[](std::size_t size, void* ptr) noexcept;
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void* operator new(std::size_t size, const std::nothrow_t&) noexcept;
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void* operator new[](std::size_t size, const std::nothrow_t&) noexcept;
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int overloadedNew() {
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char buf[sizeof(int)];
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new(&buf[0]) int(5);
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int five = *(int*)buf;
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new(buf) int[1];
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*(int*)buf = 4;
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new(std::nothrow) int(3); // memory leak
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new(std::nothrow) int[2]; // memory leak
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return five;
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}
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