[clang][bytecode] Add support for typeid pointers

clang/lib/AST/ByteCode/Compiler.cpp

@@ -3426,6 +3426,38 @@ bool Compiler<Emitter>::VisitBlockExpr(const BlockExpr *E) {
   return this->emitGetFnPtr(Func, E);
 }
 
+template <class Emitter>
+bool Compiler<Emitter>::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
+  const Type *TypeInfoType = E->getType().getTypePtr();
+
+  if (!E->isPotentiallyEvaluated()) {
+    if (DiscardResult)
+      return true;
+
+    if (E->isTypeOperand())
+      return this->emitGetTypeid(
+          E->getTypeOperand(Ctx.getASTContext()).getTypePtr(), TypeInfoType, E);
+    return this->emitGetTypeid(E->getExprOperand()->getType().getTypePtr(),
+                               TypeInfoType, E);
+  }
+
+  // Otherwise, we need to evaluate the expression operand.
+  assert(E->getExprOperand());
+  assert(E->getExprOperand()->isLValue());
+
+  if (!Ctx.getLangOpts().CPlusPlus20 && !this->emitDiagTypeid(E))
+    return false;
+
+  if (!this->visit(E->getExprOperand()))
+    return false;
+
+  if (!this->emitGetTypeidPtr(TypeInfoType, E))
+    return false;
+  if (DiscardResult)
+    return this->emitPopPtr(E);
+  return true;
+}
+
 template <class Emitter>
 bool Compiler<Emitter>::VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
   assert(Ctx.getLangOpts().CPlusPlus);

clang/lib/AST/ByteCode/Compiler.h

@@ -205,6 +205,7 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
   bool VisitCXXNewExpr(const CXXNewExpr *E);
   bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
   bool VisitBlockExpr(const BlockExpr *E);
+  bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
 
   // Statements.
   bool visitCompoundStmt(const CompoundStmt *S);

clang/lib/AST/ByteCode/Interp.cpp

@@ -1154,6 +1154,53 @@ bool CheckLiteralType(InterpState &S, CodePtr OpPC, const Type *T) {
   return false;
 }
 
+static bool getField(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
+                     uint32_t Off) {
+  if (S.getLangOpts().CPlusPlus && S.inConstantContext() &&
+      !CheckNull(S, OpPC, Ptr, CSK_Field))
+    return false;
+
+  if (!CheckExtern(S, OpPC, Ptr))
+    return false;
+  if (!CheckRange(S, OpPC, Ptr, CSK_Field))
+    return false;
+  if (!CheckArray(S, OpPC, Ptr))
+    return false;
+  if (!CheckSubobject(S, OpPC, Ptr, CSK_Field))
+    return false;
+
+  if (Ptr.isIntegralPointer()) {
+    S.Stk.push<Pointer>(Ptr.asIntPointer().atOffset(S.getASTContext(), Off));
+    return true;
+  }
+
+  if (!Ptr.isBlockPointer()) {
+    // FIXME: The only time we (seem to) get here is when trying to access a
+    // field of a typeid pointer. In that case, we're supposed to diagnose e.g.
+    // `typeid(int).name`, but we currently diagnose `&typeid(int)`.
+    S.FFDiag(S.Current->getSource(OpPC),
+             diag::note_constexpr_access_unreadable_object)
+        << AK_Read << Ptr.toDiagnosticString(S.getASTContext());
+    return false;
+  }
+
+  if (Off > Ptr.block()->getSize())
+    return false;
+
+  S.Stk.push<Pointer>(Ptr.atField(Off));
+  return true;
+}
+
+bool GetPtrField(InterpState &S, CodePtr OpPC, uint32_t Off) {
+  const auto &Ptr = S.Stk.peek<Pointer>();
+  return getField(S, OpPC, Ptr, Off);
+}
+
+bool GetPtrFieldPop(InterpState &S, CodePtr OpPC, uint32_t Off) {
+  const auto &Ptr = S.Stk.pop<Pointer>();
+  return getField(S, OpPC, Ptr, Off);
+}
+
 static bool checkConstructor(InterpState &S, CodePtr OpPC, const Function *Func,
                              const Pointer &ThisPtr) {
   assert(Func->isConstructor());
@@ -1595,6 +1642,41 @@ bool CheckBitCast(InterpState &S, CodePtr OpPC, bool HasIndeterminateBits,
   return false;
 }
 
+bool GetTypeid(InterpState &S, CodePtr OpPC, const Type *TypePtr,
+               const Type *TypeInfoType) {
+  S.Stk.push<Pointer>(TypePtr, TypeInfoType);
+  return true;
+}
+
+bool GetTypeidPtr(InterpState &S, CodePtr OpPC, const Type *TypeInfoType) {
+  const auto &P = S.Stk.pop<Pointer>();
+
+  if (!P.isBlockPointer())
+    return false;
+
+  if (P.isDummy()) {
+    QualType StarThisType =
+        S.getASTContext().getLValueReferenceType(P.getType());
+    S.FFDiag(S.Current->getSource(OpPC),
+             diag::note_constexpr_polymorphic_unknown_dynamic_type)
+        << AK_TypeId
+        << P.toAPValue(S.getASTContext())
+               .getAsString(S.getASTContext(), StarThisType);
+    return false;
+  }
+
+  S.Stk.push<Pointer>(P.getType().getTypePtr(), TypeInfoType);
+  return true;
+}
+
+bool DiagTypeid(InterpState &S, CodePtr OpPC) {
+  const auto *E = cast<CXXTypeidExpr>(S.Current->getExpr(OpPC));
+  S.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
+      << E->getExprOperand()->getType()
+      << E->getExprOperand()->getSourceRange();
+  return false;
+}
+
 // https://github.com/llvm/llvm-project/issues/102513
 #if defined(_MSC_VER) && !defined(__clang__) && !defined(NDEBUG)
 #pragma optimize("", off)

clang/lib/AST/ByteCode/Interp.h

@@ -1526,61 +1526,8 @@ inline bool GetPtrGlobal(InterpState &S, CodePtr OpPC, uint32_t I) {
 
 /// 1) Peeks a Pointer
 /// 2) Pushes Pointer.atField(Off) on the stack
-inline bool GetPtrField(InterpState &S, CodePtr OpPC, uint32_t Off) {
-  const Pointer &Ptr = S.Stk.peek<Pointer>();
-
-  if (S.getLangOpts().CPlusPlus && S.inConstantContext() &&
-      !CheckNull(S, OpPC, Ptr, CSK_Field))
-    return false;
-
-  if (!CheckExtern(S, OpPC, Ptr))
-    return false;
-  if (!CheckRange(S, OpPC, Ptr, CSK_Field))
-    return false;
-  if (!CheckArray(S, OpPC, Ptr))
-    return false;
-  if (!CheckSubobject(S, OpPC, Ptr, CSK_Field))
-    return false;
-
-  if (Ptr.isBlockPointer() && Off > Ptr.block()->getSize())
-    return false;
-
-  if (Ptr.isIntegralPointer()) {
-    S.Stk.push<Pointer>(Ptr.asIntPointer().atOffset(S.getASTContext(), Off));
-    return true;
-  }
-
-  S.Stk.push<Pointer>(Ptr.atField(Off));
-  return true;
-}
-
-inline bool GetPtrFieldPop(InterpState &S, CodePtr OpPC, uint32_t Off) {
-  const Pointer &Ptr = S.Stk.pop<Pointer>();
-
-  if (S.getLangOpts().CPlusPlus && S.inConstantContext() &&
-      !CheckNull(S, OpPC, Ptr, CSK_Field))
-    return false;
-
-  if (!CheckExtern(S, OpPC, Ptr))
-    return false;
-  if (!CheckRange(S, OpPC, Ptr, CSK_Field))
-    return false;
-  if (!CheckArray(S, OpPC, Ptr))
-    return false;
-  if (!CheckSubobject(S, OpPC, Ptr, CSK_Field))
-    return false;
-
-  if (Ptr.isBlockPointer() && Off > Ptr.block()->getSize())
-    return false;
-
-  if (Ptr.isIntegralPointer()) {
-    S.Stk.push<Pointer>(Ptr.asIntPointer().atOffset(S.getASTContext(), Off));
-    return true;
-  }
-
-  S.Stk.push<Pointer>(Ptr.atField(Off));
-  return true;
-}
+bool GetPtrField(InterpState &S, CodePtr OpPC, uint32_t Off);
+bool GetPtrFieldPop(InterpState &S, CodePtr OpPC, uint32_t Off);
 
 inline bool GetPtrThisField(InterpState &S, CodePtr OpPC, uint32_t Off) {
   if (S.checkingPotentialConstantExpression())
@@ -3087,6 +3034,12 @@ inline bool BitCast(InterpState &S, CodePtr OpPC) {
   return true;
 }
 
+/// Typeid support.
+bool GetTypeid(InterpState &S, CodePtr OpPC, const Type *TypePtr,
+               const Type *TypeInfoType);
+bool GetTypeidPtr(InterpState &S, CodePtr OpPC, const Type *TypeInfoType);
+bool DiagTypeid(InterpState &S, CodePtr OpPC);
+
 //===----------------------------------------------------------------------===//
 // Read opcode arguments
 //===----------------------------------------------------------------------===//

clang/lib/AST/ByteCode/Opcodes.td

@@ -850,3 +850,7 @@ def BitCastPrim : Opcode {
 }
 
 def BitCast : Opcode;
+
+def GetTypeid : Opcode { let Args = [ArgTypePtr, ArgTypePtr]; }
+def GetTypeidPtr : Opcode { let Args = [ArgTypePtr]; }
+def DiagTypeid : Opcode;

clang/lib/AST/ByteCode/Pointer.cpp

@@ -96,6 +96,8 @@ void Pointer::operator=(const Pointer &P) {
     PointeeStorage.Int = P.PointeeStorage.Int;
   } else if (P.isFunctionPointer()) {
     PointeeStorage.Fn = P.PointeeStorage.Fn;
+  } else if (P.isTypeidPointer()) {
+    PointeeStorage.Typeid = P.PointeeStorage.Typeid;
   } else {
     assert(false && "Unhandled storage kind");
   }
@@ -132,6 +134,8 @@ void Pointer::operator=(Pointer &&P) {
     PointeeStorage.Int = P.PointeeStorage.Int;
   } else if (P.isFunctionPointer()) {
     PointeeStorage.Fn = P.PointeeStorage.Fn;
+  } else if (P.isTypeidPointer()) {
+    PointeeStorage.Typeid = P.PointeeStorage.Typeid;
   } else {
     assert(false && "Unhandled storage kind");
   }
@@ -151,6 +155,14 @@ APValue Pointer::toAPValue(const ASTContext &ASTCtx) const {
   if (isFunctionPointer())
     return asFunctionPointer().toAPValue(ASTCtx);
 
+  if (isTypeidPointer()) {
+    TypeInfoLValue TypeInfo(PointeeStorage.Typeid.TypePtr);
+    return APValue(
+        APValue::LValueBase::getTypeInfo(
+            TypeInfo, QualType(PointeeStorage.Typeid.TypeInfoType, 0)),
+        CharUnits::Zero(), APValue::NoLValuePath{});
+  }
+
   // Build the lvalue base from the block.
   const Descriptor *Desc = getDeclDesc();
   APValue::LValueBase Base;
@@ -304,6 +316,8 @@ void Pointer::print(llvm::raw_ostream &OS) const {
   case Storage::Fn:
     OS << "(Fn) { " << asFunctionPointer().getFunction() << " + " << Offset
        << " }";
+  case Storage::Typeid:
+    OS << "(Typeid)";
   }
 }
 
@@ -450,6 +464,8 @@ bool Pointer::hasSameBase(const Pointer &A, const Pointer &B) {
     return true;
   if (A.isFunctionPointer() && B.isFunctionPointer())
     return true;
+  if (A.isTypeidPointer() && B.isTypeidPointer())
+    return true;
 
   if (A.isIntegralPointer() || B.isIntegralPointer())
     return A.getSource() == B.getSource();

clang/lib/AST/ByteCode/Pointer.h

@@ -49,7 +49,12 @@ struct IntPointer {
   IntPointer baseCast(const ASTContext &ASTCtx, unsigned BaseOffset) const;
 };
 
-enum class Storage { Block, Int, Fn };
+struct TypeidPointer {
+  const Type *TypePtr;
+  const Type *TypeInfoType;
+};
+
+enum class Storage { Block, Int, Fn, Typeid };
 
 /// A pointer to a memory block, live or dead.
 ///
@@ -107,6 +112,11 @@ class Pointer {
       : Offset(Offset), StorageKind(Storage::Fn) {
     PointeeStorage.Fn = FunctionPointer(F);
   }
+  Pointer(const Type *TypePtr, const Type *TypeInfoType, uint64_t Offset = 0)
+      : Offset(Offset), StorageKind(Storage::Typeid) {
+    PointeeStorage.Typeid.TypePtr = TypePtr;
+    PointeeStorage.Typeid.TypeInfoType = TypeInfoType;
+  }
   Pointer(Block *Pointee, unsigned Base, uint64_t Offset);
   ~Pointer();
 
@@ -263,6 +273,8 @@ class Pointer {
       return asBlockPointer().Pointee == nullptr;
     if (isFunctionPointer())
       return asFunctionPointer().isZero();
+    if (isTypeidPointer())
+      return false;
     assert(isIntegralPointer());
     return asIntPointer().Value == 0 && Offset == 0;
   }
@@ -284,7 +296,7 @@ class Pointer {
   const Descriptor *getDeclDesc() const {
     if (isIntegralPointer())
       return asIntPointer().Desc;
-    if (isFunctionPointer())
+    if (isFunctionPointer() || isTypeidPointer())
       return nullptr;
 
     assert(isBlockPointer());
@@ -337,6 +349,9 @@ class Pointer {
 
   /// Returns the type of the innermost field.
   QualType getType() const {
+    if (isTypeidPointer())
+      return QualType(PointeeStorage.Typeid.TypeInfoType, 0);
+
     if (inPrimitiveArray() && Offset != asBlockPointer().Base) {
       // Unfortunately, complex and vector types are not array types in clang,
       // but they are for us.
@@ -437,7 +452,7 @@ class Pointer {
   }
   /// Pointer points directly to a block.
   bool isRoot() const {
-    if (isZero() || isIntegralPointer())
+    if (isZero() || !isBlockPointer())
       return true;
     return (asBlockPointer().Base ==
                 asBlockPointer().Pointee->getDescriptor()->getMetadataSize() ||
@@ -467,6 +482,7 @@ class Pointer {
   bool isBlockPointer() const { return StorageKind == Storage::Block; }
   bool isIntegralPointer() const { return StorageKind == Storage::Int; }
   bool isFunctionPointer() const { return StorageKind == Storage::Fn; }
+  bool isTypeidPointer() const { return StorageKind == Storage::Typeid; }
 
   /// Returns the record descriptor of a class.
   const Record *getRecord() const { return getFieldDesc()->ElemRecord; }
@@ -605,7 +621,7 @@ class Pointer {
 
   /// Checks if the index is one past end.
   bool isOnePastEnd() const {
-    if (isIntegralPointer() || isFunctionPointer())
+    if (!isBlockPointer())
       return false;
 
     if (!asBlockPointer().Pointee)
@@ -746,6 +762,7 @@ class Pointer {
     BlockPointer BS;
     IntPointer Int;
     FunctionPointer Fn;
+    TypeidPointer Typeid;
   } PointeeStorage;
   Storage StorageKind = Storage::Int;
 };