[mlir][NFC] Apply rule of five to *Pass classes

Define all special member functions for mlir::Pass, mlir::OperationPass,
mlir::PassWrapper and PassGen types since these classes explicitly specify
copy-ctor. This, subsequently, should silence static analysis checkers that
report rule-of-3 / rule-of-5 violations.

Given the nature of the types, however, mark other special member
functions deleted: the semantics of a Pass type object seems to be that
it is only ever created by being wrapped in a smart pointer, so the
special member functions are never to be used externally (except for the
copy-ctor - it is "special" since it is a "delegating" ctor for derived
pass types to use during cloning - see https://reviews.llvm.org/D104302
for details).

Deleting other member functions means that `Pass x(std::move(y))` - that
used to silently work (via copy-ctor) - would fail to compile now. Yet,
as the copy ctors through the hierarchy are under 'protected' access, the
issue is unlikely to appear in practice.

Co-authored-by: Asya Pronina <[email protected]>
Co-authored-by: Harald Rotuna <[email protected]>

Author: 3 people

mlir/include/mlir/Pass/Pass.h

@@ -161,6 +161,9 @@ class Pass {
   explicit Pass(TypeID passID, std::optional<StringRef> opName = std::nullopt)
       : passID(passID), opName(opName) {}
   Pass(const Pass &other) : Pass(other.passID, other.opName) {}
+  Pass &operator=(const Pass &) = delete;
+  Pass(Pass &&) = delete;
+  Pass &operator=(Pass &&) = delete;
 
   /// Returns the current pass state.
   detail::PassExecutionState &getPassState() {
@@ -349,9 +352,15 @@ class Pass {
 ///   - A 'std::unique_ptr<Pass> clonePass() const' method.
 template <typename OpT = void>
 class OperationPass : public Pass {
+public:
+  ~OperationPass() = default;
+
 protected:
   OperationPass(TypeID passID) : Pass(passID, OpT::getOperationName()) {}
   OperationPass(const OperationPass &) = default;
+  OperationPass &operator=(const OperationPass &) = delete;
+  OperationPass(OperationPass &&) = delete;
+  OperationPass &operator=(OperationPass &&) = delete;
 
   /// Support isa/dyn_cast functionality.
   static bool classof(const Pass *pass) {
@@ -388,9 +397,15 @@ class OperationPass : public Pass {
 ///   - A 'std::unique_ptr<Pass> clonePass() const' method.
 template <>
 class OperationPass<void> : public Pass {
+public:
+  ~OperationPass() = default;
+
 protected:
   OperationPass(TypeID passID) : Pass(passID) {}
   OperationPass(const OperationPass &) = default;
+  OperationPass &operator=(const OperationPass &) = delete;
+  OperationPass(OperationPass &&) = delete;
+  OperationPass &operator=(OperationPass &&) = delete;
 
   /// Indicate if the current pass can be scheduled on the given operation type.
   /// By default, generic operation passes can be scheduled on any operation.
@@ -444,10 +459,14 @@ class PassWrapper : public BaseT {
   static bool classof(const Pass *pass) {
     return pass->getTypeID() == TypeID::get<PassT>();
   }
+  ~PassWrapper() = default;
 
 protected:
   PassWrapper() : BaseT(TypeID::get<PassT>()) {}
   PassWrapper(const PassWrapper &) = default;
+  PassWrapper &operator=(const PassWrapper &) = delete;
+  PassWrapper(PassWrapper &&) = delete;
+  PassWrapper &operator=(PassWrapper &&) = delete;
 
   /// Returns the derived pass name.
   StringRef getName() const override { return llvm::getTypeName<PassT>(); }

mlir/tools/mlir-tblgen/PassGen.cpp

@@ -183,6 +183,10 @@ class {0}Base : public {1} {
 
   {0}Base() : {1}(::mlir::TypeID::get<DerivedT>()) {{}
   {0}Base(const {0}Base &other) : {1}(other) {{}
+  {0}Base& operator=(const {0}Base &) = delete;
+  {0}Base({0}Base &&) = delete;
+  {0}Base& operator=({0}Base &&) = delete;
+  ~{0}Base() = default;
 
   /// Returns the command-line argument attached to this pass.
   static constexpr ::llvm::StringLiteral getArgumentName() {
@@ -380,6 +384,10 @@ class {0}Base : public {1} {
 
   {0}Base() : {1}(::mlir::TypeID::get<DerivedT>()) {{}
   {0}Base(const {0}Base &other) : {1}(other) {{}
+  {0}Base& operator=(const {0}Base &) = delete;
+  {0}Base({0}Base &&) = delete;
+  {0}Base& operator=({0}Base &&) = delete;
+  ~{0}Base() = default;
 
   /// Returns the command-line argument attached to this pass.
   static constexpr ::llvm::StringLiteral getArgumentName() {