DILParser.h

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//===-- DILParser.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_DILPARSER_H
#define LLDB_VALUEOBJECT_DILPARSER_H
 
#include "lldb/Host/common/DiagnosticsRendering.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Utility/Status.h"
#include "lldb/ValueObject/DILAST.h"
#include "lldb/ValueObject/DILLexer.h"
#include "llvm/Support/Error.h"
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <tuple>
#include <vector>
 
namespace lldb_private {
class StackFrame;
}
 
namespace lldb_private::dil {
 
enum class ErrorCode : unsigned char {
  kOk = 0,
  kInvalidExpressionSyntax,
  kUndeclaredIdentifier,
  kUnknown,
};
 
CompilerType ResolveTypeByName(const std::string &name,
                               ExecutionContext &exe_ctx);
 
// The following is modeled on class OptionParseError.
class DILDiagnosticError
    : public llvm::ErrorInfo<DILDiagnosticError, DiagnosticError> {
  DiagnosticDetail m_detail;
 
public:
  using llvm::ErrorInfo<DILDiagnosticError, DiagnosticError>::ErrorInfo;
  DILDiagnosticError(DiagnosticDetail detail)
      : ErrorInfo(make_error_code(std::errc::invalid_argument)),
        m_detail(std::move(detail)) {}
 
  DILDiagnosticError(llvm::StringRef expr, const std::string &message,
                     uint32_t loc, uint16_t err_len = 1);
 
  std::unique_ptr<CloneableError> Clone() const override {
    return std::make_unique<DILDiagnosticError>(m_detail);
  }
 
  llvm::ArrayRef<DiagnosticDetail> GetDetails() const override {
    return m_detail;
  }
 
  std::string message() const override { return m_detail.rendered; }
};
 
/// Pure recursive descent parser for C++ like expressions.
/// EBNF grammar for the parser is described in lldb/docs/dil-expr-lang.ebnf
class DILParser {
public:
  /// Parse the lexed tokens.
  /// \returns An ASTNode tree or an error.
  static llvm::Expected<ASTNodeUP>
  Parse(ExecutionContext &exe_ctx, llvm::StringRef dil_input_expr,
        DILLexer lexer, lldb::DynamicValueType use_dynamic, lldb::DILMode mode);
 
  ~DILParser() = default;
 
private:
  explicit DILParser(ExecutionContext &exe_ctx, llvm::StringRef dil_input_expr,
                     DILLexer lexer, lldb::DynamicValueType use_dynamic,
                     llvm::Error &error, lldb::DILMode mode);
 
  ASTNodeUP Run();
 
  ASTNodeUP ParseExpression();
  ASTNodeUP ParseAssignmentExpression();
  ASTNodeUP ParsePureExpression();
  ASTNodeUP ParseConditionalExpression();
  ASTNodeUP ParseConditionalBranches(ASTNodeUP condition);
  ASTNodeUP ParseLogicalOrExpression();
  ASTNodeUP ParseLogicalAndExpression();
  ASTNodeUP ParseInclusiveOrExpression();
  ASTNodeUP ParseExclusiveOrExpression();
  ASTNodeUP ParseAndExpression();
  ASTNodeUP ParseEqualityExpression();
  ASTNodeUP ParseRelationalExpression();
  ASTNodeUP ParseShiftExpression();
  ASTNodeUP ParseAdditiveExpression();
  ASTNodeUP ParseMultiplicativeExpression();
  ASTNodeUP ParseUnaryExpression();
  ASTNodeUP ParsePostfixExpression();
  ASTNodeUP ParsePrimaryExpression();
 
  std::string ParseNestedNameSpecifier();
 
  std::string ParseIdExpression();
  std::string ParseUnqualifiedId();
  ASTNodeUP ParseNumericLiteral();
  ASTNodeUP ParseIntegerLiteral();
  ASTNodeUP ParseFloatingPointLiteral();
  ASTNodeUP ParseBooleanLiteral();
 
  ASTNodeUP ParseCastExpression();
  std::optional<CompilerType> ParseBuiltinType();
  std::optional<CompilerType> ParseTypeId();
  void ParseTypeSpecifierSeq(std::string &type_name);
  std::optional<std::string> ParseTypeSpecifier();
  std::optional<std::string> ParseTypeName();
  CompilerType ResolveTypeDeclarators(CompilerType type,
                                      const std::vector<Token> &ptr_operators);
 
  void BailOut(const std::string &error, uint32_t loc, uint16_t err_len);
 
  void Expect(Token::Kind kind);
 
  void ExpectOneOf(std::vector<Token::Kind> kinds_vec);
 
  void TentativeParsingRollback(uint32_t saved_idx) {
    if (m_error)
      llvm::consumeError(std::move(m_error));
    m_dil_lexer.ResetTokenIdx(saved_idx);
  }
 
  Token CurToken() { return m_dil_lexer.GetCurrentToken(); }
 
  // Parser doesn't own the evaluation context. The produced AST may depend on
  // it (for example, for source locations), so it's expected that expression
  // context will outlive the parser.
  ExecutionContext m_exe_ctx;
 
  llvm::StringRef m_input_expr;
 
  DILLexer m_dil_lexer;
 
  // Holds an error if it occures during parsing.
  llvm::Error &m_error;
 
  lldb::DynamicValueType m_use_dynamic;
 
  // DIL Mode requested by the caller.
  lldb::DILMode m_mode;
}; // class DILParser
 
} // namespace lldb_private::dil
 
#endif // LLDB_VALUEOBJECT_DILPARSER_H