================ @@ -0,0 +1,308 @@ +//===-- DILParser.cpp -----------------------------------------------------===// +// +// 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 implements the recursive descent parser for the Data Inspection +// Language (DIL), and its helper functions, which will eventually underlie the +// 'frame variable' command. The language that this parser recognizes is +// described in lldb/docs/dil-expr-lang.ebnf +// +//===----------------------------------------------------------------------===// + +#include "lldb/ValueObject/DILParser.h" +#include "lldb/Target/ExecutionContextScope.h" +#include "lldb/ValueObject/DILAST.h" +#include "lldb/ValueObject/DILEval.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/Support/FormatAdapters.h" +#include <limits.h> +#include <memory> +#include <sstream> +#include <stdlib.h> +#include <string> + +namespace lldb_private::dil { + +inline void TokenKindsJoinImpl(std::ostringstream &os, Token::Kind k) { + os << "'" << Token::GetTokenName(k).str() << "'"; +} + +template <typename... Ts> +inline void TokenKindsJoinImpl(std::ostringstream &os, Token::Kind k, + Ts... ks) { + TokenKindsJoinImpl(os, k); + os << ", "; + TokenKindsJoinImpl(os, ks...); +} + +template <typename... Ts> +inline std::string TokenKindsJoin(Token::Kind k, Ts... ks) { + std::ostringstream os; + TokenKindsJoinImpl(os, k, ks...); + + return os.str(); +} + +std::string FormatDiagnostics(llvm::StringRef text, const std::string &message, + uint32_t loc) { + // Get the source buffer and the location of the current token. + size_t loc_offset = (size_t)loc; + + // Look for the start of the line. + size_t line_start = text.rfind('\n', loc_offset); + line_start = line_start == llvm::StringRef::npos ? 0 : line_start + 1; + + // Look for the end of the line. + size_t line_end = text.find('\n', loc_offset); + line_end = line_end == llvm::StringRef::npos ? text.size() : line_end; + + // Get a view of the current line in the source code and the position of the + // diagnostics pointer. + llvm::StringRef line = text.slice(line_start, line_end); + int32_t arrow = loc + 1; // Column offset starts at 1, not 0. + + // Calculate the padding in case we point outside of the expression (this can + // happen if the parser expected something, but got EOF).˚ + size_t expr_rpad = std::max(0, arrow - static_cast<int32_t>(line.size())); + size_t arrow_rpad = std::max(0, static_cast<int32_t>(line.size()) - arrow); + + return llvm::formatv("<expr:1:{0}>: {1}\n{2}\n{3}", loc, message, + llvm::fmt_pad(line, 0, expr_rpad), + llvm::fmt_pad("^", arrow - 1, arrow_rpad)); +} + +DILParser::DILParser(llvm::StringRef dil_input_expr, DILLexer lexer, + std::shared_ptr<ExecutionContextScope> exe_ctx_scope, + lldb::DynamicValueType use_dynamic, bool use_synthetic, + bool fragile_ivar, bool check_ptr_vs_member) + : m_ctx_scope(exe_ctx_scope), m_input_expr(dil_input_expr), + m_dil_lexer(lexer), m_dil_token(lexer.GetCurrentToken()), + m_use_dynamic(use_dynamic), m_use_synthetic(use_synthetic), + m_fragile_ivar(fragile_ivar), m_check_ptr_vs_member(check_ptr_vs_member) { +} + +llvm::Expected<DILASTNodeUP> DILParser::Run() { + DILASTNodeUP expr; + + expr = ParseExpression(); + + Expect(Token::Kind::eof); + + if (m_error.Fail()) + return m_error.ToError(); + + return expr; +} + +// Parse an expression. +// +// expression: +// primary_expression +// +DILASTNodeUP DILParser::ParseExpression() { return ParsePrimaryExpression(); } + +// Parse a primary_expression. +// +// primary_expression: +// id_expression +// "this" +// "(" expression ")" +// +DILASTNodeUP DILParser::ParsePrimaryExpression() { + if (m_dil_token.IsOneOf(Token::coloncolon, Token::identifier)) { + // Save the source location for the diagnostics message. + uint32_t loc = m_dil_token.GetLocation(); + auto identifier = ParseIdExpression(); + + return std::make_unique<IdentifierNode>(loc, identifier, m_use_dynamic, + m_ctx_scope); + } else if (m_dil_token.Is(Token::l_paren)) { + ConsumeToken(); + auto expr = ParseExpression(); + Expect(Token::r_paren); + ConsumeToken(); + return expr; + } + + BailOut(ErrorCode::kInvalidExpressionSyntax, + llvm::formatv("Unexpected token: {0}", TokenDescription(m_dil_token)), + m_dil_token.GetLocation()); + return std::make_unique<ErrorNode>(); +} + +// Parse nested_name_specifier. +// +// nested_name_specifier: +// type_name "::" +// namespace_name "::" +// nested_name_specifier identifier "::" +// +std::string DILParser::ParseNestedNameSpecifier() { + // The first token in nested_name_specifier is always an identifier, or + // '(anonymous namespace)'. + if (m_dil_token.IsNot(Token::identifier) && + m_dil_token.IsNot(Token::l_paren)) { + return ""; + } + + // Anonymous namespaces need to be treated specially: They are represented + // the the string '(anonymous namespace)', which has a space in it (throwing + // off normal parsing) and is not actually proper C++> Check to see if we're + // looking at '(anonymous namespace)::...' + if (m_dil_token.Is(Token::l_paren)) { + // Look for all the pieces, in order: + // l_paren 'anonymous' 'namespace' r_paren coloncolon + if (m_dil_lexer.LookAhead(1).Is(Token::identifier) && + (m_dil_lexer.LookAhead(1).GetSpelling() == "anonymous") && + m_dil_lexer.LookAhead(2).Is(Token::identifier) && + (m_dil_lexer.LookAhead(2).GetSpelling() == "namespace") && + m_dil_lexer.LookAhead(3).Is(Token::r_paren) && + m_dil_lexer.LookAhead(4).Is(Token::coloncolon)) { + m_dil_lexer.Advance(4); + m_dil_token = m_dil_lexer.GetCurrentToken(); + + assert((m_dil_token.Is(Token::identifier) || + m_dil_token.Is(Token::l_paren)) && + "Expected an identifier or anonymous namespace, but not found."); + // Continue parsing the nested_namespace_specifier. + std::string identifier2 = ParseNestedNameSpecifier(); + if (identifier2.empty()) { + Expect(Token::identifier); + identifier2 = m_dil_token.GetSpelling(); + ConsumeToken(); + } + return "(anonymous namespace)::" + identifier2; + } + + return ""; + } // end of special handling for '(anonymous namespace)' + + // If the next token is scope ("::"), then this is indeed a + // nested_name_specifier + if (m_dil_lexer.LookAhead(1).Is(Token::coloncolon)) { + // This nested_name_specifier is a single identifier. + std::string identifier = m_dil_token.GetSpelling(); + m_dil_lexer.Advance(1); + m_dil_token = m_dil_lexer.GetCurrentToken(); + Expect(Token::coloncolon); + ConsumeToken(); + // Continue parsing the nested_name_specifier. + return identifier + "::" + ParseNestedNameSpecifier(); + } + + return ""; +} + +// Parse an id_expression. +// +// id_expression: +// unqualified_id +// qualified_id +// +// qualified_id: +// ["::"] [nested_name_specifier] unqualified_id +// ["::"] identifier +// +// identifier: +// ? Token::identifier ? +// +std::string DILParser::ParseIdExpression() { + // Try parsing optional global scope operator. + bool global_scope = false; + if (m_dil_token.Is(Token::coloncolon)) { + global_scope = true; + ConsumeToken(); + } + + // Try parsing optional nested_name_specifier. + auto nested_name_specifier = ParseNestedNameSpecifier(); + + // If nested_name_specifier is present, then it's qualified_id production. + // Follow the first production rule. + if (!nested_name_specifier.empty()) { + // Parse unqualified_id and construct a fully qualified id expression. + auto unqualified_id = ParseUnqualifiedId(); + + return llvm::formatv("{0}{1}{2}", global_scope ? "::" : "", + nested_name_specifier, unqualified_id); + } + + // No nested_name_specifier, but with global scope -- this is also a + // qualified_id production. Follow the second production rule. + else if (global_scope) { + Expect(Token::identifier); + std::string identifier = m_dil_token.GetSpelling(); + ConsumeToken(); + return llvm::formatv("{0}{1}", global_scope ? "::" : "", identifier); + } + + // This is unqualified_id production. + return ParseUnqualifiedId(); +} + +// Parse an unqualified_id. +// +// unqualified_id: +// identifier +// +// identifier: +// ? Token::identifier ? +// +std::string DILParser::ParseUnqualifiedId() { + Expect(Token::identifier); + std::string identifier = m_dil_token.GetSpelling(); + ConsumeToken(); + return identifier; +} + +void DILParser::BailOut(ErrorCode code, const std::string &error, + uint32_t loc) { + if (m_error.Fail()) { + // If error is already set, then the parser is in the "bail-out" mode. Don't + // do anything and keep the original error. + return; + } + + m_error = Status((uint32_t)code, lldb::eErrorTypeGeneric, + FormatDiagnostics(m_input_expr, error, loc)); + m_dil_token = Token(Token::eof, "", 0); +} + +void DILParser::BailOut(Status error) { + if (m_error.Fail()) { + // If error is already set, then the parser is in the "bail-out" mode. Don't + // do anything and keep the original error. + return; + } + m_error = std::move(error); + m_dil_token = Token(Token::eof, "", 0); +} + +void DILParser::ConsumeToken() { + if (m_dil_token.Is(Token::eof)) { + // Don't do anything if we're already at eof. This can happen if an error + // occurred during parsing and we're trying to bail out. + return; + } + m_dil_lexer.Advance(); + m_dil_token = m_dil_lexer.GetCurrentToken(); +} + +void DILParser::Expect(Token::Kind kind) { + if (m_dil_token.IsNot(kind)) { + BailOut(ErrorCode::kUnknown, + llvm::formatv("expected {0}, got: {1}", TokenKindsJoin(kind), + TokenDescription(m_dil_token)), + m_dil_token.GetLocation()); + } +} + +std::string DILParser::TokenDescription(const Token &token) { ---------------- cmtice wrote:
Same questions as above. https://github.com/llvm/llvm-project/pull/120971 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
