Fix zero-array in 'struct hack'

Author: fabianbs96

include/phasar/PhasarLLVM/DataFlowSolver/IfdsIde/Problems/ExtendedTaintAnalysis/AbstractMemoryLocation.h

@@ -38,7 +38,9 @@ struct AbstractMemoryLoactionStorage : public llvm::FoldingSetNode {
   const llvm::Value *Baseptr;
   uint32_t Lifetime;
   uint32_t NumOffsets;
-  ptrdiff_t Offsets[0]; // NOLINT
+  /// The actual length of Offsets is a runtime-constant determined by
+  /// NumOffsets. Note, that NumOffsets can be larger than 1
+  ptrdiff_t Offsets[1]; // NOLINT
 
 protected:
   AbstractMemoryLoactionStorage(

include/phasar/PhasarLLVM/DataFlowSolver/IfdsIde/Problems/ExtendedTaintAnalysis/AbstractMemoryLocationFactory.h

@@ -37,7 +37,7 @@ class AbstractMemoryLocationFactoryBase {
   struct Allocator {
     struct Block {
       Block *Next = nullptr;
-      void *Data[0];
+      void *Data[1]; // NOLINT
 
       static Block *create(Block *Next, size_t NumPointerEntries);
       static void destroy(Block *Blck);
@@ -49,18 +49,23 @@ class AbstractMemoryLocationFactoryBase {
     Block *Root = nullptr;
     void **Pos = nullptr, **End = nullptr;
 
-    Allocator() = default;
+    Allocator() noexcept = default;
     Allocator(size_t InitialCapacity);
+    Allocator(const Allocator &) = delete;
+    Allocator(Allocator &&Other) noexcept;
     ~Allocator();
 
+    Allocator &operator=(const Allocator &) = delete;
+    Allocator &operator=(Allocator &&Other) noexcept;
+
     AbstractMemoryLocationImpl *create(const llvm::Value *Baseptr,
                                        size_t Lifetime,
                                        llvm::ArrayRef<ptrdiff_t> Offsets);
 
   private:
     constexpr static size_t ExpectedNumAmLsPerBlock = 1024;
     constexpr static size_t MinNumPointersPerAML =
-        sizeof(AbstractMemoryLocationImpl) / sizeof(void *);
+        offsetof(AbstractMemoryLocationImpl, Offsets) / sizeof(void *);
     constexpr static size_t NumPointersPerBlock =
         (MinNumPointersPerAML + 3) * ExpectedNumAmLsPerBlock;
   };

lib/PhasarLLVM/DataFlowSolver/IfdsIde/Problems/ExtendedTaintAnalysis/AbstractMemoryLocationFactory.cpp

@@ -17,6 +17,9 @@
 
 namespace psr::detail {
 
+/// We intentionally don't initialize the Data member as it will be a dynamic
+/// array at runtime
+// NOLINTNEXTLINE (cppcoreguidelines-pro-type-member-init)
 AbstractMemoryLocationFactoryBase::Allocator::Block::Block(Block *Next)
     : Next(Next) {}
 
@@ -34,6 +37,11 @@ auto AbstractMemoryLocationFactoryBase::Allocator::Block::create(
     std::terminate();
   }
 
+  static_assert(
+      alignof(AbstractMemoryLocationImpl) == alignof(size_t),
+      "The alignment of the AbstractMemoryLocationImpl allocation cannot be "
+      "guaranteed as it differs from the alignment of size_t");
+
   auto *Ret = reinterpret_cast<Block *>(new size_t[1 + NumPointerEntries]);
 
   new (Ret) Block(Next);
@@ -69,6 +77,21 @@ AbstractMemoryLocationFactoryBase::Allocator::~Allocator() {
   End = nullptr;
 }
 
+AbstractMemoryLocationFactoryBase::Allocator::Allocator(
+    Allocator &&Other) noexcept
+    : Root(Other.Root), Pos(Other.Pos), End(Other.End) {
+  Other.Root = nullptr;
+  Other.Pos = nullptr;
+  Other.End = nullptr;
+}
+
+auto AbstractMemoryLocationFactoryBase::Allocator::operator=(
+    Allocator &&Other) noexcept -> Allocator & {
+  this->Allocator::~Allocator();
+  new (this) Allocator(std::move(Other));
+  return *this;
+}
+
 AbstractMemoryLocationImpl *
 AbstractMemoryLocationFactoryBase::Allocator::create(
     const llvm::Value *Baseptr, size_t Lifetime,