Unverified Commit 8b258206 authored by Timm Baeder's avatar Timm Baeder Committed by GitHub
Browse files

[clang][bytecode] Diagnose copying empty mutable unions (#195529) 

We had a special case for copy/move ctors of empty unions. Remove that.
Everything else is just so we don't regress diagnostics.
parent a9a899db

clang/lib/AST/ByteCode/Compiler.cpp

+4 −3
Original line number Diff line number Diff line
@@ -6809,12 +6809,13 @@ bool Compiler<Emitter>::compileConstructor(const CXXConstructorDecl *Ctor) { 
    return false;

  bool IsUnion = R->isUnion();



  // Union copy and move ctors are special.

  if (IsUnion && Ctor->isCopyOrMoveConstructor()) {

    LocOverrideScope<Emitter> LOS(this, SourceInfo{});



    if (R->getNumFields() == 0)

      return this->emitRetVoid(Ctor);

    // union copy and move ctors are special.

    // No special case for NumFields == 0 here, so the Memcpy op

    // below also does its checks in those cases.



    assert(cast<CompoundStmt>(Ctor->getBody())->body_empty());

    if (!this->emitThis(Ctor))

      return false;

clang/lib/AST/ByteCode/Function.cpp

+2 −1
Original line number Diff line number Diff line
@@ -29,7 +29,8 @@ Function::Function(Program &P, FunctionDeclTy Source, unsigned ArgSize, 
    Constexpr = F->isConstexpr();

    if (const auto *CD = dyn_cast<CXXConstructorDecl>(F)) {

      Virtual = CD->isVirtual();

      Kind = FunctionKind::Ctor;

      Kind = CD->isCopyOrMoveConstructor() ? FunctionKind::CopyOrMoveCtor

                                           : FunctionKind::Ctor;

    } else if (const auto *CD = dyn_cast<CXXDestructorDecl>(F)) {

      Virtual = CD->isVirtual();

      Kind = FunctionKind::Dtor;

clang/lib/AST/ByteCode/Function.h

+8 −1
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ public: 
  enum class FunctionKind {

    Normal,

    Ctor,

    CopyOrMoveCtor,

    Dtor,

    LambdaStaticInvoker,

    LambdaCallOperator,
@@ -185,7 +186,13 @@ public: 
  bool isConstexpr() const { return Constexpr; }



  /// Checks if the function is a constructor.

  bool isConstructor() const { return Kind == FunctionKind::Ctor; }

  bool isConstructor() const {

    return Kind == FunctionKind::Ctor || Kind == FunctionKind::CopyOrMoveCtor;

  }

  bool isCopyOrMoveConstructor() const {

    return Kind == FunctionKind::CopyOrMoveCtor;

  }



  /// Checks if the function is a destructor.

  bool isDestructor() const { return Kind == FunctionKind::Dtor; }

  /// Checks if the function is copy or move operator.

clang/lib/AST/ByteCode/Interp.cpp

+10 −0
Original line number Diff line number Diff line
@@ -910,6 +910,8 @@ static bool CheckInvoke(InterpState &S, CodePtr OpPC, const Pointer &Ptr, 
      return false;

    if (!IsCtorDtor && !CheckLifetime(S, OpPC, Ptr, AK_MemberCall))

      return false;

    if (!CheckMutable(S, OpPC, Ptr))

      return false;

  }

  return true;

}
@@ -1781,6 +1783,14 @@ bool Call(InterpState &S, CodePtr OpPC, const Function *Func, 
      if (!CheckInvoke(S, OpPC, ThisPtr,

                       Func->isConstructor() || Func->isDestructor()))

        return cleanup();



      if (Func->isCopyOrMoveOperator() || Func->isCopyOrMoveConstructor()) {

        const Pointer &RVOPtr =

            S.Stk.peek<Pointer>(ThisOffset - align(sizeof(Pointer)));

        if (!CheckInvoke(S, OpPC, RVOPtr, /*IsCtorDtor=*/true))

          return cleanup();

      }



      if (!Func->isConstructor() && !Func->isDestructor() &&

          !CheckActive(S, OpPC, ThisPtr, AK_MemberCall))

        return false;

clang/lib/AST/ByteCode/InterpFrame.cpp

+0 −5
Original line number Diff line number Diff line
@@ -150,11 +150,6 @@ static bool shouldSkipInBacktrace(const Function *F) { 
      MD && MD->getParent()->isAnonymousStructOrUnion())

    return true;



  if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(FD);

      Ctor && Ctor->isDefaulted() && Ctor->isTrivial() &&

      Ctor->isCopyOrMoveConstructor() && Ctor->inits().empty())

    return true;



  return false;

}