UnwindTable.h

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//===-- UnwindTable.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_SYMBOL_UNWINDTABLE_H
#define LLDB_SYMBOL_UNWINDTABLE_H
 
#include <atomic>
#include <map>
#include <mutex>
#include <optional>
 
#include "lldb/lldb-private.h"
 
namespace lldb_private {
 
// A class which holds all the FuncUnwinders objects for a given ObjectFile.
// The UnwindTable is populated with FuncUnwinders objects lazily during the
// debug session.
 
class UnwindTable {
public:
  /// Create an Unwind table using the data in the given module.
  explicit UnwindTable(Module &module);
 
  ~UnwindTable();
 
  lldb_private::CallFrameInfo *GetObjectFileUnwindInfo();
 
  lldb_private::DWARFCallFrameInfo *GetEHFrameInfo();
  lldb_private::DWARFCallFrameInfo *GetDebugFrameInfo();
 
  lldb_private::CompactUnwindInfo *GetCompactUnwindInfo();
 
  ArmUnwindInfo *GetArmUnwindInfo();
  SymbolFile *GetSymbolFile();
 
  lldb::FuncUnwindersSP
  GetFuncUnwindersContainingAddress(const Address &addr,
                                    const SymbolContext &sc);
 
  /// Return the start of the function containing \p addr according to the
  /// object file's own unwind info (the .pdata RUNTIME_FUNCTION on PE/COFF
  /// x64), or an invalid address if there is none.
  Address GetFunctionStartFromObjectFileUnwindInfo(const Address &addr);
 
  bool GetAllowAssemblyEmulationUnwindPlans();
 
  // Normally when we create a new FuncUnwinders object we track it in this
  // UnwindTable so it can be reused later.  But for the target modules show-
  // unwind we want to create brand new UnwindPlans for the function of
  // interest - so ignore any existing FuncUnwinders for that function and
  // don't add this new one to our UnwindTable. This FuncUnwinders object does
  // have a reference to the UnwindTable but the lifetime of this uncached
  // FuncUnwinders is expected to be short so in practice this will not be a
  // problem.
  lldb::FuncUnwindersSP
  GetUncachedFuncUnwindersContainingAddress(const Address &addr,
                                            const SymbolContext &sc);
 
  ArchSpec GetArchitecture();
 
  /// Called after an ObjectFile/SymbolFile has been added to a Module to add
  /// any new unwind sections that may now be available.
  void ModuleWasUpdated();
 
private:
  void Dump(Stream &s);
 
  void Initialize();
  AddressRanges GetAddressRanges(const Address &addr, const SymbolContext &sc);
 
  typedef std::map<lldb::addr_t, lldb::FuncUnwindersSP> collection;
  typedef collection::iterator iterator;
  typedef collection::const_iterator const_iterator;
 
  Module &m_module;
  collection m_unwinds;
 
  /// This is true when we have looked at the ObjectFile and SymbolFile for all
  /// sources of unwind information; false if we haven't done that yet, or one
  /// of the files has been updated in the Module.
  std::atomic<bool> m_scanned_all_unwind_sources;
  std::mutex m_mutex;
 
  std::unique_ptr<CallFrameInfo> m_object_file_unwind_up;
  std::unique_ptr<DWARFCallFrameInfo> m_eh_frame_up;
  std::unique_ptr<DWARFCallFrameInfo> m_debug_frame_up;
  std::unique_ptr<CompactUnwindInfo> m_compact_unwind_up;
  std::unique_ptr<ArmUnwindInfo> m_arm_unwind_up;
 
  UnwindTable(const UnwindTable &) = delete;
  const UnwindTable &operator=(const UnwindTable &) = delete;
};
 
} // namespace lldb_private
 
#endif // LLDB_SYMBOL_UNWINDTABLE_H