Ed Maste d13f691f41 Improve FreeBSD kernel debugging
FreeBSD kernel modules are actually relocatable (.o) ELF files and this
previously caused some issues for LLDB. This change addresses these when
using lldb to symbolicate FreeBSD kernel backtraces. 

The major problems:

- Relocations were not being applied to the DWARF debug info despite
  there being code to do this. Several issues prevented it from working:

  - Relocations are computed at the same time as the symbol table, but
    in the case of split debug files, symbol table parsing always
    redirects to the primary object file, meaning that relocations would
    never be applied in the debug file.

  - There's actually no guarantee that the symbol table has been parsed
    yet when trying to parse debug information.

  - When actually applying relocations, it will segfault because the
    object files are not mapped with MAP_PRIVATE and PROT_WRITE.

- LLDB returned invalid results when performing ordinary address-to-
  symbol resolution. It turned out that the addresses specified in the
  section headers were all 0, so LLDB believed all the sections had
  overlapping "file addresses" and would sometimes return a symbol from
  the wrong section.

Patch by Brian Koropoff

Differential Revision:	https://reviews.llvm.org/D38142

llvm-svn: 314672
2017-10-02 14:35:07 +00:00

114 lines
3.9 KiB
C++

//===-- ObjectFileJIT.h -----------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef liblldb_ObjectFileJIT_h_
#define liblldb_ObjectFileJIT_h_
// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Core/Address.h"
#include "lldb/Symbol/ObjectFile.h"
//----------------------------------------------------------------------
// This class needs to be hidden as eventually belongs in a plugin that
// will export the ObjectFile protocol
//----------------------------------------------------------------------
class ObjectFileJIT : public lldb_private::ObjectFile {
public:
ObjectFileJIT(const lldb::ModuleSP &module_sp,
const lldb::ObjectFileJITDelegateSP &delegate_sp);
~ObjectFileJIT() override;
//------------------------------------------------------------------
// Static Functions
//------------------------------------------------------------------
static void Initialize();
static void Terminate();
static lldb_private::ConstString GetPluginNameStatic();
static const char *GetPluginDescriptionStatic();
static lldb_private::ObjectFile *
CreateInstance(const lldb::ModuleSP &module_sp, lldb::DataBufferSP &data_sp,
lldb::offset_t data_offset, const lldb_private::FileSpec *file,
lldb::offset_t file_offset, lldb::offset_t length);
static lldb_private::ObjectFile *CreateMemoryInstance(
const lldb::ModuleSP &module_sp, lldb::DataBufferSP &data_sp,
const lldb::ProcessSP &process_sp, lldb::addr_t header_addr);
static size_t GetModuleSpecifications(const lldb_private::FileSpec &file,
lldb::DataBufferSP &data_sp,
lldb::offset_t data_offset,
lldb::offset_t file_offset,
lldb::offset_t length,
lldb_private::ModuleSpecList &specs);
//------------------------------------------------------------------
// Member Functions
//------------------------------------------------------------------
bool ParseHeader() override;
bool SetLoadAddress(lldb_private::Target &target, lldb::addr_t value,
bool value_is_offset) override;
lldb::ByteOrder GetByteOrder() const override;
bool IsExecutable() const override;
uint32_t GetAddressByteSize() const override;
lldb_private::Symtab *GetSymtab() override;
bool IsStripped() override;
void CreateSections(lldb_private::SectionList &unified_section_list) override;
void Dump(lldb_private::Stream *s) override;
bool GetArchitecture(lldb_private::ArchSpec &arch) override;
bool GetUUID(lldb_private::UUID *uuid) override;
uint32_t GetDependentModules(lldb_private::FileSpecList &files) override;
size_t ReadSectionData(lldb_private::Section *section,
lldb::offset_t section_offset, void *dst,
size_t dst_len) override;
size_t
ReadSectionData(lldb_private::Section *section,
lldb_private::DataExtractor &section_data) override;
lldb_private::Address GetEntryPointAddress() override;
lldb_private::Address GetHeaderAddress() override;
ObjectFile::Type CalculateType() override;
ObjectFile::Strata CalculateStrata() override;
//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
lldb_private::ConstString GetPluginName() override;
uint32_t GetPluginVersion() override;
protected:
lldb::ObjectFileJITDelegateWP m_delegate_wp;
};
#endif // liblldb_ObjectFileJIT_h_