| //===------ EvaluationResult.h - Result class for the VM -------*- 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_AST_INTERP_EVALUATION_RESULT_H |
| #define LLVM_CLANG_AST_INTERP_EVALUATION_RESULT_H |
| |
| #include "FunctionPointer.h" |
| #include "Pointer.h" |
| #include "clang/AST/APValue.h" |
| #include "clang/AST/Decl.h" |
| #include "clang/AST/Expr.h" |
| #include <optional> |
| #include <variant> |
| |
| namespace clang { |
| namespace interp { |
| class EvalEmitter; |
| class Context; |
| |
| /// Defines the result of an evaluation. |
| /// |
| /// The result might be in different forms--one of the pointer types, |
| /// an APValue, or nothing. |
| /// |
| /// We use this class to inspect and diagnose the result, as well as |
| /// convert it to the requested form. |
| class EvaluationResult final { |
| public: |
| enum ResultKind { |
| Empty, // Initial state. |
| LValue, // Result is an lvalue/pointer. |
| RValue, // Result is an rvalue. |
| Invalid, // Result is invalid. |
| Valid, // Result is valid and empty. |
| }; |
| |
| using DeclTy = llvm::PointerUnion<const Decl *, const Expr *>; |
| |
| private: |
| const Context *Ctx = nullptr; |
| std::variant<std::monostate, Pointer, FunctionPointer, APValue> Value; |
| ResultKind Kind = Empty; |
| DeclTy Source = nullptr; // Currently only needed for dump(). |
| |
| EvaluationResult(ResultKind Kind) : Kind(Kind) { |
| // Leave everything empty. Can be used as an |
| // error marker or for void return values. |
| assert(Kind == Valid || Kind == Invalid); |
| } |
| |
| void setSource(DeclTy D) { Source = D; } |
| |
| void setValue(const APValue &V) { |
| // V could still be an LValue. |
| assert(empty()); |
| Value = std::move(V); |
| Kind = RValue; |
| } |
| void setPointer(const Pointer P) { |
| assert(empty()); |
| Value = P; |
| Kind = LValue; |
| } |
| void setFunctionPointer(const FunctionPointer &P) { |
| assert(empty()); |
| Value = P; |
| Kind = LValue; |
| } |
| void setInvalid() { |
| // We are NOT asserting empty() here, since setting it to invalid |
| // is allowed even if there is already a result. |
| Kind = Invalid; |
| } |
| void setValid() { |
| assert(empty()); |
| Kind = Valid; |
| } |
| |
| public: |
| EvaluationResult(const Context *Ctx) : Ctx(Ctx) {} |
| |
| bool empty() const { return Kind == Empty; } |
| bool isInvalid() const { return Kind == Invalid; } |
| bool isLValue() const { return Kind == LValue; } |
| bool isRValue() const { return Kind == RValue; } |
| |
| /// Returns an APValue for the evaluation result. The returned |
| /// APValue might be an LValue or RValue. |
| APValue toAPValue() const; |
| |
| /// If the result is an LValue, convert that to an RValue |
| /// and return it. This may fail, e.g. if the result is an |
| /// LValue and we can't read from it. |
| std::optional<APValue> toRValue() const; |
| |
| bool checkFullyInitialized(InterpState &S, const Pointer &Ptr) const; |
| |
| /// Dump to stderr. |
| void dump() const; |
| |
| friend class EvalEmitter; |
| }; |
| |
| } // namespace interp |
| } // namespace clang |
| |
| #endif |