| //===- Ownership.h - Parser ownership helpers -------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains classes for managing ownership of Stmt and Expr nodes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_SEMA_OWNERSHIP_H |
| #define LLVM_CLANG_SEMA_OWNERSHIP_H |
| |
| #include "clang/AST/Expr.h" |
| #include "clang/Basic/LLVM.h" |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/Support/PointerLikeTypeTraits.h" |
| #include "llvm/Support/type_traits.h" |
| #include <cassert> |
| #include <cstddef> |
| #include <cstdint> |
| |
| //===----------------------------------------------------------------------===// |
| // OpaquePtr |
| //===----------------------------------------------------------------------===// |
| |
| namespace clang { |
| |
| class CXXBaseSpecifier; |
| class CXXCtorInitializer; |
| class Decl; |
| class Expr; |
| class ParsedTemplateArgument; |
| class QualType; |
| class Stmt; |
| class TemplateName; |
| class TemplateParameterList; |
| |
| /// Wrapper for void* pointer. |
| /// \tparam PtrTy Either a pointer type like 'T*' or a type that behaves like |
| /// a pointer. |
| /// |
| /// This is a very simple POD type that wraps a pointer that the Parser |
| /// doesn't know about but that Sema or another client does. The PtrTy |
| /// template argument is used to make sure that "Decl" pointers are not |
| /// compatible with "Type" pointers for example. |
| template <class PtrTy> |
| class OpaquePtr { |
| void *Ptr = nullptr; |
| |
| explicit OpaquePtr(void *Ptr) : Ptr(Ptr) {} |
| |
| using Traits = llvm::PointerLikeTypeTraits<PtrTy>; |
| |
| public: |
| OpaquePtr(std::nullptr_t = nullptr) {} |
| |
| static OpaquePtr make(PtrTy P) { OpaquePtr OP; OP.set(P); return OP; } |
| |
| /// Returns plain pointer to the entity pointed by this wrapper. |
| /// \tparam PointeeT Type of pointed entity. |
| /// |
| /// It is identical to getPtrAs<PointeeT*>. |
| template <typename PointeeT> PointeeT* getPtrTo() const { |
| return get(); |
| } |
| |
| /// Returns pointer converted to the specified type. |
| /// \tparam PtrT Result pointer type. There must be implicit conversion |
| /// from PtrTy to PtrT. |
| /// |
| /// In contrast to getPtrTo, this method allows the return type to be |
| /// a smart pointer. |
| template <typename PtrT> PtrT getPtrAs() const { |
| return get(); |
| } |
| |
| PtrTy get() const { |
| return Traits::getFromVoidPointer(Ptr); |
| } |
| |
| void set(PtrTy P) { |
| Ptr = Traits::getAsVoidPointer(P); |
| } |
| |
| explicit operator bool() const { return Ptr != nullptr; } |
| |
| void *getAsOpaquePtr() const { return Ptr; } |
| static OpaquePtr getFromOpaquePtr(void *P) { return OpaquePtr(P); } |
| }; |
| |
| /// UnionOpaquePtr - A version of OpaquePtr suitable for membership |
| /// in a union. |
| template <class T> struct UnionOpaquePtr { |
| void *Ptr; |
| |
| static UnionOpaquePtr make(OpaquePtr<T> P) { |
| UnionOpaquePtr OP = { P.getAsOpaquePtr() }; |
| return OP; |
| } |
| |
| OpaquePtr<T> get() const { return OpaquePtr<T>::getFromOpaquePtr(Ptr); } |
| operator OpaquePtr<T>() const { return get(); } |
| |
| UnionOpaquePtr &operator=(OpaquePtr<T> P) { |
| Ptr = P.getAsOpaquePtr(); |
| return *this; |
| } |
| }; |
| |
| } // namespace clang |
| |
| namespace llvm { |
| |
| template <class T> |
| struct PointerLikeTypeTraits<clang::OpaquePtr<T>> { |
| enum { NumLowBitsAvailable = 0 }; |
| |
| static inline void *getAsVoidPointer(clang::OpaquePtr<T> P) { |
| // FIXME: Doesn't work? return P.getAs< void >(); |
| return P.getAsOpaquePtr(); |
| } |
| |
| static inline clang::OpaquePtr<T> getFromVoidPointer(void *P) { |
| return clang::OpaquePtr<T>::getFromOpaquePtr(P); |
| } |
| }; |
| |
| } // namespace llvm |
| |
| namespace clang { |
| |
| // Basic |
| class DiagnosticBuilder; |
| |
| // Determines whether the low bit of the result pointer for the |
| // given UID is always zero. If so, ActionResult will use that bit |
| // for it's "invalid" flag. |
| template<class Ptr> |
| struct IsResultPtrLowBitFree { |
| static const bool value = false; |
| }; |
| |
| /// ActionResult - This structure is used while parsing/acting on |
| /// expressions, stmts, etc. It encapsulates both the object returned by |
| /// the action, plus a sense of whether or not it is valid. |
| /// When CompressInvalid is true, the "invalid" flag will be |
| /// stored in the low bit of the Val pointer. |
| template<class PtrTy, |
| bool CompressInvalid = IsResultPtrLowBitFree<PtrTy>::value> |
| class ActionResult { |
| PtrTy Val; |
| bool Invalid; |
| |
| public: |
| ActionResult(bool Invalid = false) : Val(PtrTy()), Invalid(Invalid) {} |
| ActionResult(PtrTy val) : Val(val), Invalid(false) {} |
| ActionResult(const DiagnosticBuilder &) : Val(PtrTy()), Invalid(true) {} |
| |
| // These two overloads prevent void* -> bool conversions. |
| ActionResult(const void *) = delete; |
| ActionResult(volatile void *) = delete; |
| |
| bool isInvalid() const { return Invalid; } |
| bool isUsable() const { return !Invalid && Val; } |
| bool isUnset() const { return !Invalid && !Val; } |
| |
| PtrTy get() const { return Val; } |
| template <typename T> T *getAs() { return static_cast<T*>(get()); } |
| |
| void set(PtrTy V) { Val = V; } |
| |
| const ActionResult &operator=(PtrTy RHS) { |
| Val = RHS; |
| Invalid = false; |
| return *this; |
| } |
| }; |
| |
| // This ActionResult partial specialization places the "invalid" |
| // flag into the low bit of the pointer. |
| template<typename PtrTy> |
| class ActionResult<PtrTy, true> { |
| // A pointer whose low bit is 1 if this result is invalid, 0 |
| // otherwise. |
| uintptr_t PtrWithInvalid; |
| |
| using PtrTraits = llvm::PointerLikeTypeTraits<PtrTy>; |
| |
| public: |
| ActionResult(bool Invalid = false) |
| : PtrWithInvalid(static_cast<uintptr_t>(Invalid)) {} |
| |
| ActionResult(PtrTy V) { |
| void *VP = PtrTraits::getAsVoidPointer(V); |
| PtrWithInvalid = reinterpret_cast<uintptr_t>(VP); |
| assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer"); |
| } |
| |
| ActionResult(const DiagnosticBuilder &) : PtrWithInvalid(0x01) {} |
| |
| // These two overloads prevent void* -> bool conversions. |
| ActionResult(const void *) = delete; |
| ActionResult(volatile void *) = delete; |
| |
| bool isInvalid() const { return PtrWithInvalid & 0x01; } |
| bool isUsable() const { return PtrWithInvalid > 0x01; } |
| bool isUnset() const { return PtrWithInvalid == 0; } |
| |
| PtrTy get() const { |
| void *VP = reinterpret_cast<void *>(PtrWithInvalid & ~0x01); |
| return PtrTraits::getFromVoidPointer(VP); |
| } |
| |
| template <typename T> T *getAs() { return static_cast<T*>(get()); } |
| |
| void set(PtrTy V) { |
| void *VP = PtrTraits::getAsVoidPointer(V); |
| PtrWithInvalid = reinterpret_cast<uintptr_t>(VP); |
| assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer"); |
| } |
| |
| const ActionResult &operator=(PtrTy RHS) { |
| void *VP = PtrTraits::getAsVoidPointer(RHS); |
| PtrWithInvalid = reinterpret_cast<uintptr_t>(VP); |
| assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer"); |
| return *this; |
| } |
| |
| // For types where we can fit a flag in with the pointer, provide |
| // conversions to/from pointer type. |
| static ActionResult getFromOpaquePointer(void *P) { |
| ActionResult Result; |
| Result.PtrWithInvalid = (uintptr_t)P; |
| return Result; |
| } |
| void *getAsOpaquePointer() const { return (void*)PtrWithInvalid; } |
| }; |
| |
| /// An opaque type for threading parsed type information through the |
| /// parser. |
| using ParsedType = OpaquePtr<QualType>; |
| using UnionParsedType = UnionOpaquePtr<QualType>; |
| |
| // We can re-use the low bit of expression, statement, base, and |
| // member-initializer pointers for the "invalid" flag of |
| // ActionResult. |
| template<> struct IsResultPtrLowBitFree<Expr*> { |
| static const bool value = true; |
| }; |
| template<> struct IsResultPtrLowBitFree<Stmt*> { |
| static const bool value = true; |
| }; |
| template<> struct IsResultPtrLowBitFree<CXXBaseSpecifier*> { |
| static const bool value = true; |
| }; |
| template<> struct IsResultPtrLowBitFree<CXXCtorInitializer*> { |
| static const bool value = true; |
| }; |
| |
| using ExprResult = ActionResult<Expr *>; |
| using StmtResult = ActionResult<Stmt *>; |
| using TypeResult = ActionResult<ParsedType>; |
| using BaseResult = ActionResult<CXXBaseSpecifier *>; |
| using MemInitResult = ActionResult<CXXCtorInitializer *>; |
| |
| using DeclResult = ActionResult<Decl *>; |
| using ParsedTemplateTy = OpaquePtr<TemplateName>; |
| using UnionParsedTemplateTy = UnionOpaquePtr<TemplateName>; |
| |
| using MultiExprArg = MutableArrayRef<Expr *>; |
| using MultiStmtArg = MutableArrayRef<Stmt *>; |
| using ASTTemplateArgsPtr = MutableArrayRef<ParsedTemplateArgument>; |
| using MultiTypeArg = MutableArrayRef<ParsedType>; |
| using MultiTemplateParamsArg = MutableArrayRef<TemplateParameterList *>; |
| |
| inline ExprResult ExprError() { return ExprResult(true); } |
| inline StmtResult StmtError() { return StmtResult(true); } |
| |
| inline ExprResult ExprError(const DiagnosticBuilder&) { return ExprError(); } |
| inline StmtResult StmtError(const DiagnosticBuilder&) { return StmtError(); } |
| |
| inline ExprResult ExprEmpty() { return ExprResult(false); } |
| inline StmtResult StmtEmpty() { return StmtResult(false); } |
| |
| inline Expr *AssertSuccess(ExprResult R) { |
| assert(!R.isInvalid() && "operation was asserted to never fail!"); |
| return R.get(); |
| } |
| |
| inline Stmt *AssertSuccess(StmtResult R) { |
| assert(!R.isInvalid() && "operation was asserted to never fail!"); |
| return R.get(); |
| } |
| |
| } // namespace clang |
| |
| #endif // LLVM_CLANG_SEMA_OWNERSHIP_H |