================ @@ -0,0 +1,132 @@ +//===-- DILLexer.h ----------------------------------------------*- 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 LLDB_VALUEOBJECT_DILLEXER_H_ +#define LLDB_VALUEOBJECT_DILLEXER_H_ + +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/iterator_range.h" +#include "llvm/Support/Error.h" +#include <cstdint> +#include <limits.h> +#include <memory> +#include <string> +#include <vector> + +namespace lldb_private::dil { + +/// Class defining the tokens generated by the DIL lexer and used by the +/// DIL parser. +class Token { +public: + enum Kind { + coloncolon, + eof, + identifier, + l_paren, + r_paren, + unknown, + }; + + Token(Kind kind, std::string spelling, uint32_t start) + : m_kind(kind), m_spelling(std::move(spelling)), m_start_pos(start) {} + + Kind GetKind() const { return m_kind; } + + std::string GetSpelling() const { return m_spelling; } + + bool Is(Kind kind) const { return m_kind == kind; } + + bool IsNot(Kind kind) const { return m_kind != kind; } + + bool IsOneOf(Kind kind1, Kind kind2) const { return Is(kind1) || Is(kind2); } + + template <typename... Ts> bool IsOneOf(Kind kind, Ts... Ks) const { + return Is(kind) || IsOneOf(Ks...); + } + + uint32_t GetLocation() const { return m_start_pos; } + + static llvm::StringRef GetTokenName(Kind kind); + +private: + Kind m_kind; + std::string m_spelling; + uint32_t m_start_pos; // within entire expression string +}; + +/// Class for doing the simple lexing required by DIL. +class DILLexer { +public: + /// Lexes all the tokens in expr and calls the private constructor + /// with the lexed tokens. + static llvm::Expected<DILLexer> Create(llvm::StringRef expr); + + /// Return the current token to be handled by the DIL parser. + const Token &GetCurrentToken() { return m_lexed_tokens[m_tokens_idx]; } + + /// Advance the current token position by N. + void Advance(uint32_t N = 1) { + // UINT_MAX means uninitialized, no "current" position, so move to start. + if (m_tokens_idx == UINT_MAX) + m_tokens_idx = 0; + else if (m_tokens_idx + N >= m_lexed_tokens.size()) + // N is too large; advance to the end of the lexed tokens. + m_tokens_idx = m_lexed_tokens.size() - 1; + else + m_tokens_idx += N; + } + + /// Return the lexed token N positions ahead of the 'current' token + /// being handled by the DIL parser. + const Token &LookAhead(uint32_t N) { + if (m_tokens_idx + N < m_lexed_tokens.size()) + return m_lexed_tokens[m_tokens_idx + N]; + + // Last token should be an 'eof' token. + return m_lexed_tokens.back(); + } + + /// Return the index for the 'current' token being handled by the DIL parser. + uint32_t GetCurrentTokenIdx() { return m_tokens_idx; } + + /// Set the index for the 'current' token (to be handled by the parser) + /// to a particular position. Used for either committing 'look ahead' parsing + /// or rolling back tentative parsing. + void ResetTokenIdx(uint32_t new_value) { + assert(new_value == UINT_MAX || new_value < m_lexed_tokens.size()); + m_tokens_idx = new_value; + } + + uint32_t NumLexedTokens() { return m_lexed_tokens.size(); } + +private: + DILLexer(llvm::StringRef dil_expr, std::vector<Token> lexed_tokens) + : m_expr(dil_expr), m_lexed_tokens(std::move(lexed_tokens)), + m_tokens_idx(UINT_MAX), m_eof_token(Token(Token::eof, "", 0)) {} + + static llvm::Expected<Token> Lex(llvm::StringRef expr, + llvm::StringRef &remainder); + + // The input string we are lexing & parsing. + llvm::StringRef m_expr; + + // Holds all of the tokens lexed so far. + std::vector<Token> m_lexed_tokens; + + // Index into m_lexed_tokens; indicates which token the DIL parser is + // currently trying to parse/handle. + uint32_t m_tokens_idx; + + // "eof" token; to be returned by lexer when 'look ahead' fails. + Token m_eof_token; +}; ---------------- labath wrote:
```suggestion }; ``` https://github.com/llvm/llvm-project/pull/123521 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
