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llvm-capstone/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
Greg Clayton 5ce9c5657c <rdar://problem/13159777> 
lldb was mmap'ing archive files once per .o file it loads, now it correctly shares the archive between modules.

LLDB was also always mapping entire contents of universal mach-o files, now it maps just the slice that is required.

Added a new logging channel for "lldb" called "mmap" to help track future regressions.

Modified the ObjectFile and ObjectContainer plugin interfaces to take a data offset along with the file offset and size so we can implement the correct caching and efficient reading of parts of files without mmap'ing the entire file like we used to.

The current implementation still keeps entire .a files mmaped (once) and entire slices from universal files mmaped to ensure that if a client builds their binaries during a debug session we don't lose our data and get corrupt object file info and debug info.

llvm-svn: 174524
2013-02-06 17:22:03 +00:00

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//===-- ObjectFileELF.cpp ------------------------------------- -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ObjectFileELF.h"
#include <cassert>
#include <algorithm>
#include "lldb/Core/ArchSpec.h"
#include "lldb/Core/DataBuffer.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/FileSpecList.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Section.h"
#include "lldb/Core/Stream.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Host/Host.h"
#include "llvm/ADT/PointerUnion.h"
#define CASE_AND_STREAM(s, def, width) \
case def: s->Printf("%-*s", width, #def); break;
using namespace lldb;
using namespace lldb_private;
using namespace elf;
using namespace llvm::ELF;
namespace {
//===----------------------------------------------------------------------===//
/// @class ELFRelocation
/// @brief Generic wrapper for ELFRel and ELFRela.
///
/// This helper class allows us to parse both ELFRel and ELFRela relocation
/// entries in a generic manner.
class ELFRelocation
{
public:
/// Constructs an ELFRelocation entry with a personality as given by @p
/// type.
///
/// @param type Either DT_REL or DT_RELA. Any other value is invalid.
ELFRelocation(unsigned type);
~ELFRelocation();
bool
Parse(const lldb_private::DataExtractor &data, lldb::offset_t *offset);
static unsigned
RelocType32(const ELFRelocation &rel);
static unsigned
RelocType64(const ELFRelocation &rel);
static unsigned
RelocSymbol32(const ELFRelocation &rel);
static unsigned
RelocSymbol64(const ELFRelocation &rel);
private:
typedef llvm::PointerUnion<ELFRel*, ELFRela*> RelocUnion;
RelocUnion reloc;
};
ELFRelocation::ELFRelocation(unsigned type)
{
if (type == DT_REL)
reloc = new ELFRel();
else if (type == DT_RELA)
reloc = new ELFRela();
else {
assert(false && "unexpected relocation type");
reloc = static_cast<ELFRel*>(NULL);
}
}
ELFRelocation::~ELFRelocation()
{
if (reloc.is<ELFRel*>())
delete reloc.get<ELFRel*>();
else
delete reloc.get<ELFRela*>();
}
bool
ELFRelocation::Parse(const lldb_private::DataExtractor &data, lldb::offset_t *offset)
{
if (reloc.is<ELFRel*>())
return reloc.get<ELFRel*>()->Parse(data, offset);
else
return reloc.get<ELFRela*>()->Parse(data, offset);
}
unsigned
ELFRelocation::RelocType32(const ELFRelocation &rel)
{
if (rel.reloc.is<ELFRel*>())
return ELFRel::RelocType32(*rel.reloc.get<ELFRel*>());
else
return ELFRela::RelocType32(*rel.reloc.get<ELFRela*>());
}
unsigned
ELFRelocation::RelocType64(const ELFRelocation &rel)
{
if (rel.reloc.is<ELFRel*>())
return ELFRel::RelocType64(*rel.reloc.get<ELFRel*>());
else
return ELFRela::RelocType64(*rel.reloc.get<ELFRela*>());
}
unsigned
ELFRelocation::RelocSymbol32(const ELFRelocation &rel)
{
if (rel.reloc.is<ELFRel*>())
return ELFRel::RelocSymbol32(*rel.reloc.get<ELFRel*>());
else
return ELFRela::RelocSymbol32(*rel.reloc.get<ELFRela*>());
}
unsigned
ELFRelocation::RelocSymbol64(const ELFRelocation &rel)
{
if (rel.reloc.is<ELFRel*>())
return ELFRel::RelocSymbol64(*rel.reloc.get<ELFRel*>());
else
return ELFRela::RelocSymbol64(*rel.reloc.get<ELFRela*>());
}
} // end anonymous namespace
//------------------------------------------------------------------
// Static methods.
//------------------------------------------------------------------
void
ObjectFileELF::Initialize()
{
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(),
CreateInstance,
CreateMemoryInstance);
}
void
ObjectFileELF::Terminate()
{
PluginManager::UnregisterPlugin(CreateInstance);
}
const char *
ObjectFileELF::GetPluginNameStatic()
{
return "object-file.elf";
}
const char *
ObjectFileELF::GetPluginDescriptionStatic()
{
return "ELF object file reader.";
}
ObjectFile *
ObjectFileELF::CreateInstance (const lldb::ModuleSP &module_sp,
DataBufferSP &data_sp,
lldb::offset_t data_offset,
const lldb_private::FileSpec* file,
lldb::offset_t file_offset,
lldb::offset_t length)
{
if (!data_sp)
{
data_sp = file->MemoryMapFileContents(file_offset, length);
data_offset = 0;
}
if (data_sp && data_sp->GetByteSize() > (llvm::ELF::EI_NIDENT + data_offset))
{
const uint8_t *magic = data_sp->GetBytes() + data_offset;
if (ELFHeader::MagicBytesMatch(magic))
{
// Update the data to contain the entire file
// Update the data to contain the entire file if it doesn't already
if (data_sp->GetByteSize() < length)
data_sp = file->MemoryMapFileContents(file_offset, length);
unsigned address_size = ELFHeader::AddressSizeInBytes(magic);
if (address_size == 4 || address_size == 8)
{
std::auto_ptr<ObjectFileELF> objfile_ap(new ObjectFileELF(module_sp, data_sp, data_offset, file, file_offset, length));
ArchSpec spec;
if (objfile_ap->GetArchitecture(spec) &&
objfile_ap->SetModulesArchitecture(spec))
return objfile_ap.release();
}
}
}
return NULL;
}
ObjectFile*
ObjectFileELF::CreateMemoryInstance (const lldb::ModuleSP &module_sp,
DataBufferSP& data_sp,
const lldb::ProcessSP &process_sp,
lldb::addr_t header_addr)
{
return NULL;
}
//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
const char *
ObjectFileELF::GetPluginName()
{
return "ObjectFileELF";
}
const char *
ObjectFileELF::GetShortPluginName()
{
return GetPluginNameStatic();
}
uint32_t
ObjectFileELF::GetPluginVersion()
{
return m_plugin_version;
}
//------------------------------------------------------------------
// ObjectFile protocol
//------------------------------------------------------------------
ObjectFileELF::ObjectFileELF (const lldb::ModuleSP &module_sp,
DataBufferSP& data_sp,
lldb::offset_t data_offset,
const FileSpec* file,
lldb::offset_t file_offset,
lldb::offset_t length) :
ObjectFile(module_sp, file, file_offset, length, data_sp, data_offset),
m_header(),
m_program_headers(),
m_section_headers(),
m_sections_ap(),
m_symtab_ap(),
m_filespec_ap(),
m_shstr_data()
{
if (file)
m_file = *file;
::memset(&m_header, 0, sizeof(m_header));
}
ObjectFileELF::~ObjectFileELF()
{
}
bool
ObjectFileELF::IsExecutable() const
{
return m_header.e_entry != 0;
}
ByteOrder
ObjectFileELF::GetByteOrder() const
{
if (m_header.e_ident[EI_DATA] == ELFDATA2MSB)
return eByteOrderBig;
if (m_header.e_ident[EI_DATA] == ELFDATA2LSB)
return eByteOrderLittle;
return eByteOrderInvalid;
}
uint32_t
ObjectFileELF::GetAddressByteSize() const
{
return m_data.GetAddressByteSize();
}
size_t
ObjectFileELF::SectionIndex(const SectionHeaderCollIter &I)
{
return std::distance(m_section_headers.begin(), I) + 1u;
}
size_t
ObjectFileELF::SectionIndex(const SectionHeaderCollConstIter &I) const
{
return std::distance(m_section_headers.begin(), I) + 1u;
}
bool
ObjectFileELF::ParseHeader()
{
lldb::offset_t offset = GetFileOffset();
return m_header.Parse(m_data, &offset);
}
bool
ObjectFileELF::GetUUID(lldb_private::UUID* uuid)
{
// FIXME: Return MD5 sum here. See comment in ObjectFile.h.
return false;
}
uint32_t
ObjectFileELF::GetDependentModules(FileSpecList &files)
{
size_t num_modules = ParseDependentModules();
uint32_t num_specs = 0;
for (unsigned i = 0; i < num_modules; ++i)
{
if (files.AppendIfUnique(m_filespec_ap->GetFileSpecAtIndex(i)))
num_specs++;
}
return num_specs;
}
user_id_t
ObjectFileELF::GetSectionIndexByType(unsigned type)
{
if (!ParseSectionHeaders())
return 0;
for (SectionHeaderCollIter sh_pos = m_section_headers.begin();
sh_pos != m_section_headers.end(); ++sh_pos)
{
if (sh_pos->sh_type == type)
return SectionIndex(sh_pos);
}
return 0;
}
Address
ObjectFileELF::GetImageInfoAddress()
{
if (!ParseDynamicSymbols())
return Address();
SectionList *section_list = GetSectionList();
if (!section_list)
return Address();
user_id_t dynsym_id = GetSectionIndexByType(SHT_DYNAMIC);
if (!dynsym_id)
return Address();
const ELFSectionHeader *dynsym_hdr = GetSectionHeaderByIndex(dynsym_id);
if (!dynsym_hdr)
return Address();
SectionSP dynsym_section_sp (section_list->FindSectionByID(dynsym_id));
if (dynsym_section_sp)
{
for (size_t i = 0; i < m_dynamic_symbols.size(); ++i)
{
ELFDynamic &symbol = m_dynamic_symbols[i];
if (symbol.d_tag == DT_DEBUG)
{
// Compute the offset as the number of previous entries plus the
// size of d_tag.
addr_t offset = i * dynsym_hdr->sh_entsize + GetAddressByteSize();
return Address(dynsym_section_sp, offset);
}
}
}
return Address();
}
lldb_private::Address
ObjectFileELF::GetEntryPointAddress ()
{
SectionList *sections;
addr_t offset;
if (m_entry_point_address.IsValid())
return m_entry_point_address;
if (!ParseHeader() || !IsExecutable())
return m_entry_point_address;
sections = GetSectionList();
offset = m_header.e_entry;
if (!sections)
{
m_entry_point_address.SetOffset(offset);
return m_entry_point_address;
}
m_entry_point_address.ResolveAddressUsingFileSections(offset, sections);
return m_entry_point_address;
}
//----------------------------------------------------------------------
// ParseDependentModules
//----------------------------------------------------------------------
size_t
ObjectFileELF::ParseDependentModules()
{
if (m_filespec_ap.get())
return m_filespec_ap->GetSize();
m_filespec_ap.reset(new FileSpecList());
if (!(ParseSectionHeaders() && GetSectionHeaderStringTable()))
return 0;
// Locate the dynamic table.
user_id_t dynsym_id = 0;
user_id_t dynstr_id = 0;
for (SectionHeaderCollIter sh_pos = m_section_headers.begin();
sh_pos != m_section_headers.end(); ++sh_pos)
{
if (sh_pos->sh_type == SHT_DYNAMIC)
{
dynsym_id = SectionIndex(sh_pos);
dynstr_id = sh_pos->sh_link + 1; // Section ID's are 1 based.
break;
}
}
if (!(dynsym_id && dynstr_id))
return 0;
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
// Resolve and load the dynamic table entries and corresponding string
// table.
Section *dynsym = section_list->FindSectionByID(dynsym_id).get();
Section *dynstr = section_list->FindSectionByID(dynstr_id).get();
if (!(dynsym && dynstr))
return 0;
DataExtractor dynsym_data;
DataExtractor dynstr_data;
if (ReadSectionData(dynsym, dynsym_data) &&
ReadSectionData(dynstr, dynstr_data))
{
ELFDynamic symbol;
const lldb::offset_t section_size = dynsym_data.GetByteSize();
lldb::offset_t offset = 0;
// The only type of entries we are concerned with are tagged DT_NEEDED,
// yielding the name of a required library.
while (offset < section_size)
{
if (!symbol.Parse(dynsym_data, &offset))
break;
if (symbol.d_tag != DT_NEEDED)
continue;
uint32_t str_index = static_cast<uint32_t>(symbol.d_val);
const char *lib_name = dynstr_data.PeekCStr(str_index);
m_filespec_ap->Append(FileSpec(lib_name, true));
}
}
return m_filespec_ap->GetSize();
}
//----------------------------------------------------------------------
// ParseProgramHeaders
//----------------------------------------------------------------------
size_t
ObjectFileELF::ParseProgramHeaders()
{
// We have already parsed the program headers
if (!m_program_headers.empty())
return m_program_headers.size();
// If there are no program headers to read we are done.
if (m_header.e_phnum == 0)
return 0;
m_program_headers.resize(m_header.e_phnum);
if (m_program_headers.size() != m_header.e_phnum)
return 0;
const size_t ph_size = m_header.e_phnum * m_header.e_phentsize;
const elf_off ph_offset = m_header.e_phoff;
DataExtractor data;
if (GetData (ph_offset, ph_size, data) != ph_size)
return 0;
uint32_t idx;
lldb::offset_t offset;
for (idx = 0, offset = 0; idx < m_header.e_phnum; ++idx)
{
if (m_program_headers[idx].Parse(data, &offset) == false)
break;
}
if (idx < m_program_headers.size())
m_program_headers.resize(idx);
return m_program_headers.size();
}
//----------------------------------------------------------------------
// ParseSectionHeaders
//----------------------------------------------------------------------
size_t
ObjectFileELF::ParseSectionHeaders()
{
// We have already parsed the section headers
if (!m_section_headers.empty())
return m_section_headers.size();
// If there are no section headers we are done.
if (m_header.e_shnum == 0)
return 0;
m_section_headers.resize(m_header.e_shnum);
if (m_section_headers.size() != m_header.e_shnum)
return 0;
const size_t sh_size = m_header.e_shnum * m_header.e_shentsize;
const elf_off sh_offset = m_header.e_shoff;
DataExtractor data;
if (GetData (sh_offset, sh_size, data) != sh_size)
return 0;
uint32_t idx;
lldb::offset_t offset;
for (idx = 0, offset = 0; idx < m_header.e_shnum; ++idx)
{
if (m_section_headers[idx].Parse(data, &offset) == false)
break;
}
if (idx < m_section_headers.size())
m_section_headers.resize(idx);
return m_section_headers.size();
}
size_t
ObjectFileELF::GetSectionHeaderStringTable()
{
if (m_shstr_data.GetByteSize() == 0)
{
const unsigned strtab_idx = m_header.e_shstrndx;
if (strtab_idx && strtab_idx < m_section_headers.size())
{
const ELFSectionHeader &sheader = m_section_headers[strtab_idx];
const size_t byte_size = sheader.sh_size;
const Elf64_Off offset = sheader.sh_offset;
m_shstr_data.SetData (m_data, offset, byte_size);
if (m_shstr_data.GetByteSize() != byte_size)
return 0;
}
}
return m_shstr_data.GetByteSize();
}
lldb::user_id_t
ObjectFileELF::GetSectionIndexByName(const char *name)
{
if (!(ParseSectionHeaders() && GetSectionHeaderStringTable()))
return 0;
// Search the collection of section headers for one with a matching name.
for (SectionHeaderCollIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I)
{
const char *sectionName = m_shstr_data.PeekCStr(I->sh_name);
if (!sectionName)
return 0;
if (strcmp(name, sectionName) != 0)
continue;
return SectionIndex(I);
}
return 0;
}
const elf::ELFSectionHeader *
ObjectFileELF::GetSectionHeaderByIndex(lldb::user_id_t id)
{
if (!ParseSectionHeaders() || !id)
return NULL;
if (--id < m_section_headers.size())
return &m_section_headers[id];
return NULL;
}
SectionList *
ObjectFileELF::GetSectionList()
{
if (m_sections_ap.get())
return m_sections_ap.get();
if (ParseSectionHeaders() && GetSectionHeaderStringTable())
{
m_sections_ap.reset(new SectionList());
for (SectionHeaderCollIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I)
{
const ELFSectionHeader &header = *I;
ConstString name(m_shstr_data.PeekCStr(header.sh_name));
const uint64_t file_size = header.sh_type == SHT_NOBITS ? 0 : header.sh_size;
const uint64_t vm_size = header.sh_flags & SHF_ALLOC ? header.sh_size : 0;
static ConstString g_sect_name_text (".text");
static ConstString g_sect_name_data (".data");
static ConstString g_sect_name_bss (".bss");
static ConstString g_sect_name_tdata (".tdata");
static ConstString g_sect_name_tbss (".tbss");
static ConstString g_sect_name_dwarf_debug_abbrev (".debug_abbrev");
static ConstString g_sect_name_dwarf_debug_aranges (".debug_aranges");
static ConstString g_sect_name_dwarf_debug_frame (".debug_frame");
static ConstString g_sect_name_dwarf_debug_info (".debug_info");
static ConstString g_sect_name_dwarf_debug_line (".debug_line");
static ConstString g_sect_name_dwarf_debug_loc (".debug_loc");
static ConstString g_sect_name_dwarf_debug_macinfo (".debug_macinfo");
static ConstString g_sect_name_dwarf_debug_pubnames (".debug_pubnames");
static ConstString g_sect_name_dwarf_debug_pubtypes (".debug_pubtypes");
static ConstString g_sect_name_dwarf_debug_ranges (".debug_ranges");
static ConstString g_sect_name_dwarf_debug_str (".debug_str");
static ConstString g_sect_name_eh_frame (".eh_frame");
SectionType sect_type = eSectionTypeOther;
bool is_thread_specific = false;
if (name == g_sect_name_text) sect_type = eSectionTypeCode;
else if (name == g_sect_name_data) sect_type = eSectionTypeData;
else if (name == g_sect_name_bss) sect_type = eSectionTypeZeroFill;
else if (name == g_sect_name_tdata)
{
sect_type = eSectionTypeData;
is_thread_specific = true;
}
else if (name == g_sect_name_tbss)
{
sect_type = eSectionTypeZeroFill;
is_thread_specific = true;
}
else if (name == g_sect_name_dwarf_debug_abbrev) sect_type = eSectionTypeDWARFDebugAbbrev;
else if (name == g_sect_name_dwarf_debug_aranges) sect_type = eSectionTypeDWARFDebugAranges;
else if (name == g_sect_name_dwarf_debug_frame) sect_type = eSectionTypeDWARFDebugFrame;
else if (name == g_sect_name_dwarf_debug_info) sect_type = eSectionTypeDWARFDebugInfo;
else if (name == g_sect_name_dwarf_debug_line) sect_type = eSectionTypeDWARFDebugLine;
else if (name == g_sect_name_dwarf_debug_loc) sect_type = eSectionTypeDWARFDebugLoc;
else if (name == g_sect_name_dwarf_debug_macinfo) sect_type = eSectionTypeDWARFDebugMacInfo;
else if (name == g_sect_name_dwarf_debug_pubnames) sect_type = eSectionTypeDWARFDebugPubNames;
else if (name == g_sect_name_dwarf_debug_pubtypes) sect_type = eSectionTypeDWARFDebugPubTypes;
else if (name == g_sect_name_dwarf_debug_ranges) sect_type = eSectionTypeDWARFDebugRanges;
else if (name == g_sect_name_dwarf_debug_str) sect_type = eSectionTypeDWARFDebugStr;
else if (name == g_sect_name_eh_frame) sect_type = eSectionTypeEHFrame;
SectionSP section_sp(new Section(
GetModule(), // Module to which this section belongs.
SectionIndex(I), // Section ID.
name, // Section name.
sect_type, // Section type.
header.sh_addr, // VM address.
vm_size, // VM size in bytes of this section.
header.sh_offset, // Offset of this section in the file.
file_size, // Size of the section as found in the file.
header.sh_flags)); // Flags for this section.
if (is_thread_specific)
section_sp->SetIsThreadSpecific (is_thread_specific);
m_sections_ap->AddSection(section_sp);
}
m_sections_ap->Finalize(); // Now that we're done adding sections, finalize to build fast-lookup caches
}
return m_sections_ap.get();
}
static unsigned
ParseSymbols(Symtab *symtab,
user_id_t start_id,
SectionList *section_list,
const ELFSectionHeader *symtab_shdr,
const DataExtractor &symtab_data,
const DataExtractor &strtab_data)
{
ELFSymbol symbol;
lldb::offset_t offset = 0;
const size_t num_symbols = symtab_data.GetByteSize() / symtab_shdr->sh_entsize;
static ConstString text_section_name(".text");
static ConstString init_section_name(".init");
static ConstString fini_section_name(".fini");
static ConstString ctors_section_name(".ctors");
static ConstString dtors_section_name(".dtors");
static ConstString data_section_name(".data");
static ConstString rodata_section_name(".rodata");
static ConstString rodata1_section_name(".rodata1");
static ConstString data2_section_name(".data1");
static ConstString bss_section_name(".bss");
unsigned i;
for (i = 0; i < num_symbols; ++i)
{
if (symbol.Parse(symtab_data, &offset) == false)
break;
SectionSP symbol_section_sp;
SymbolType symbol_type = eSymbolTypeInvalid;
Elf64_Half symbol_idx = symbol.st_shndx;
switch (symbol_idx)
{
case SHN_ABS:
symbol_type = eSymbolTypeAbsolute;
break;
case SHN_UNDEF:
symbol_type = eSymbolTypeUndefined;
break;
default:
symbol_section_sp = section_list->GetSectionAtIndex(symbol_idx);
break;
}
switch (symbol.getType())
{
default:
case STT_NOTYPE:
// The symbol's type is not specified.
break;
case STT_OBJECT:
// The symbol is associated with a data object, such as a variable,
// an array, etc.
symbol_type = eSymbolTypeData;
break;
case STT_FUNC:
// The symbol is associated with a function or other executable code.
symbol_type = eSymbolTypeCode;
break;
case STT_SECTION:
// The symbol is associated with a section. Symbol table entries of
// this type exist primarily for relocation and normally have
// STB_LOCAL binding.
break;
case STT_FILE:
// Conventionally, the symbol's name gives the name of the source
// file associated with the object file. A file symbol has STB_LOCAL
// binding, its section index is SHN_ABS, and it precedes the other
// STB_LOCAL symbols for the file, if it is present.
symbol_type = eSymbolTypeObjectFile;
break;
}
if (symbol_type == eSymbolTypeInvalid)
{
if (symbol_section_sp)
{
const ConstString &sect_name = symbol_section_sp->GetName();
if (sect_name == text_section_name ||
sect_name == init_section_name ||
sect_name == fini_section_name ||
sect_name == ctors_section_name ||
sect_name == dtors_section_name)
{
symbol_type = eSymbolTypeCode;
}
else if (sect_name == data_section_name ||
sect_name == data2_section_name ||
sect_name == rodata_section_name ||
sect_name == rodata1_section_name ||
sect_name == bss_section_name)
{
symbol_type = eSymbolTypeData;
}
}
}
uint64_t symbol_value = symbol.st_value;
if (symbol_section_sp)
symbol_value -= symbol_section_sp->GetFileAddress();
const char *symbol_name = strtab_data.PeekCStr(symbol.st_name);
bool is_global = symbol.getBinding() == STB_GLOBAL;
uint32_t flags = symbol.st_other << 8 | symbol.st_info;
bool is_mangled = symbol_name ? (symbol_name[0] == '_' && symbol_name[1] == 'Z') : false;
Symbol dc_symbol(
i + start_id, // ID is the original symbol table index.
symbol_name, // Symbol name.
is_mangled, // Is the symbol name mangled?
symbol_type, // Type of this symbol
is_global, // Is this globally visible?
false, // Is this symbol debug info?
false, // Is this symbol a trampoline?
false, // Is this symbol artificial?
symbol_section_sp, // Section in which this symbol is defined or null.
symbol_value, // Offset in section or symbol value.
symbol.st_size, // Size in bytes of this symbol.
flags); // Symbol flags.
symtab->AddSymbol(dc_symbol);
}
return i;
}
unsigned
ObjectFileELF::ParseSymbolTable(Symtab *symbol_table, user_id_t start_id,
const ELFSectionHeader *symtab_hdr,
user_id_t symtab_id)
{
assert(symtab_hdr->sh_type == SHT_SYMTAB ||
symtab_hdr->sh_type == SHT_DYNSYM);
// Parse in the section list if needed.
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
// Section ID's are ones based.
user_id_t strtab_id = symtab_hdr->sh_link + 1;
Section *symtab = section_list->FindSectionByID(symtab_id).get();
Section *strtab = section_list->FindSectionByID(strtab_id).get();
unsigned num_symbols = 0;
if (symtab && strtab)
{
DataExtractor symtab_data;
DataExtractor strtab_data;
if (ReadSectionData(symtab, symtab_data) &&
ReadSectionData(strtab, strtab_data))
{
num_symbols = ParseSymbols(symbol_table, start_id,
section_list, symtab_hdr,
symtab_data, strtab_data);
}
}
return num_symbols;
}
size_t
ObjectFileELF::ParseDynamicSymbols()
{
if (m_dynamic_symbols.size())
return m_dynamic_symbols.size();
user_id_t dyn_id = GetSectionIndexByType(SHT_DYNAMIC);
if (!dyn_id)
return 0;
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
Section *dynsym = section_list->FindSectionByID(dyn_id).get();
if (!dynsym)
return 0;
ELFDynamic symbol;
DataExtractor dynsym_data;
if (ReadSectionData(dynsym, dynsym_data))
{
const lldb::offset_t section_size = dynsym_data.GetByteSize();
lldb::offset_t cursor = 0;
while (cursor < section_size)
{
if (!symbol.Parse(dynsym_data, &cursor))
break;
m_dynamic_symbols.push_back(symbol);
}
}
return m_dynamic_symbols.size();
}
const ELFDynamic *
ObjectFileELF::FindDynamicSymbol(unsigned tag)
{
if (!ParseDynamicSymbols())
return NULL;
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
DynamicSymbolCollIter I = m_dynamic_symbols.begin();
DynamicSymbolCollIter E = m_dynamic_symbols.end();
for ( ; I != E; ++I)
{
ELFDynamic *symbol = &*I;
if (symbol->d_tag == tag)
return symbol;
}
return NULL;
}
Section *
ObjectFileELF::PLTSection()
{
const ELFDynamic *symbol = FindDynamicSymbol(DT_JMPREL);
SectionList *section_list = GetSectionList();
if (symbol && section_list)
{
addr_t addr = symbol->d_ptr;
return section_list->FindSectionContainingFileAddress(addr).get();
}
return NULL;
}
unsigned
ObjectFileELF::PLTRelocationType()
{
const ELFDynamic *symbol = FindDynamicSymbol(DT_PLTREL);
if (symbol)
return symbol->d_val;
return 0;
}
static unsigned
ParsePLTRelocations(Symtab *symbol_table,
user_id_t start_id,
unsigned rel_type,
const ELFHeader *hdr,
const ELFSectionHeader *rel_hdr,
const ELFSectionHeader *plt_hdr,
const ELFSectionHeader *sym_hdr,
const lldb::SectionSP &plt_section_sp,
DataExtractor &rel_data,
DataExtractor &symtab_data,
DataExtractor &strtab_data)
{
ELFRelocation rel(rel_type);
ELFSymbol symbol;
lldb::offset_t offset = 0;
const elf_xword plt_entsize = plt_hdr->sh_entsize;
const elf_xword num_relocations = rel_hdr->sh_size / rel_hdr->sh_entsize;
typedef unsigned (*reloc_info_fn)(const ELFRelocation &rel);
reloc_info_fn reloc_type;
reloc_info_fn reloc_symbol;
if (hdr->Is32Bit())
{
reloc_type = ELFRelocation::RelocType32;
reloc_symbol = ELFRelocation::RelocSymbol32;
}
else
{
reloc_type = ELFRelocation::RelocType64;
reloc_symbol = ELFRelocation::RelocSymbol64;
}
unsigned slot_type = hdr->GetRelocationJumpSlotType();
unsigned i;
for (i = 0; i < num_relocations; ++i)
{
if (rel.Parse(rel_data, &offset) == false)
break;
if (reloc_type(rel) != slot_type)
continue;
lldb::offset_t symbol_offset = reloc_symbol(rel) * sym_hdr->sh_entsize;
uint64_t plt_index = (i + 1) * plt_entsize;
if (!symbol.Parse(symtab_data, &symbol_offset))
break;
const char *symbol_name = strtab_data.PeekCStr(symbol.st_name);
bool is_mangled = symbol_name ? (symbol_name[0] == '_' && symbol_name[1] == 'Z') : false;
Symbol jump_symbol(
i + start_id, // Symbol table index
symbol_name, // symbol name.
is_mangled, // is the symbol name mangled?
eSymbolTypeTrampoline, // Type of this symbol
false, // Is this globally visible?
false, // Is this symbol debug info?
true, // Is this symbol a trampoline?
true, // Is this symbol artificial?
plt_section_sp, // Section in which this symbol is defined or null.
plt_index, // Offset in section or symbol value.
plt_entsize, // Size in bytes of this symbol.
0); // Symbol flags.
symbol_table->AddSymbol(jump_symbol);
}
return i;
}
unsigned
ObjectFileELF::ParseTrampolineSymbols(Symtab *symbol_table,
user_id_t start_id,
const ELFSectionHeader *rel_hdr,
user_id_t rel_id)
{
assert(rel_hdr->sh_type == SHT_RELA || rel_hdr->sh_type == SHT_REL);
// The link field points to the asscoiated symbol table. The info field
// points to the section holding the plt.
user_id_t symtab_id = rel_hdr->sh_link;
user_id_t plt_id = rel_hdr->sh_info;
if (!symtab_id || !plt_id)
return 0;
// Section ID's are ones based;
symtab_id++;
plt_id++;
const ELFSectionHeader *plt_hdr = GetSectionHeaderByIndex(plt_id);
if (!plt_hdr)
return 0;
const ELFSectionHeader *sym_hdr = GetSectionHeaderByIndex(symtab_id);
if (!sym_hdr)
return 0;
SectionList *section_list = GetSectionList();
if (!section_list)
return 0;
Section *rel_section = section_list->FindSectionByID(rel_id).get();
if (!rel_section)
return 0;
SectionSP plt_section_sp (section_list->FindSectionByID(plt_id));
if (!plt_section_sp)
return 0;
Section *symtab = section_list->FindSectionByID(symtab_id).get();
if (!symtab)
return 0;
Section *strtab = section_list->FindSectionByID(sym_hdr->sh_link + 1).get();
if (!strtab)
return 0;
DataExtractor rel_data;
if (!ReadSectionData(rel_section, rel_data))
return 0;
DataExtractor symtab_data;
if (!ReadSectionData(symtab, symtab_data))
return 0;
DataExtractor strtab_data;
if (!ReadSectionData(strtab, strtab_data))
return 0;
unsigned rel_type = PLTRelocationType();
if (!rel_type)
return 0;
return ParsePLTRelocations (symbol_table,
start_id,
rel_type,
&m_header,
rel_hdr,
plt_hdr,
sym_hdr,
plt_section_sp,
rel_data,
symtab_data,
strtab_data);
}
Symtab *
ObjectFileELF::GetSymtab()
{
if (m_symtab_ap.get())
return m_symtab_ap.get();
Symtab *symbol_table = new Symtab(this);
m_symtab_ap.reset(symbol_table);
Mutex::Locker locker(symbol_table->GetMutex());
if (!(ParseSectionHeaders() && GetSectionHeaderStringTable()))
return symbol_table;
// Locate and parse all linker symbol tables.
uint64_t symbol_id = 0;
for (SectionHeaderCollIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I)
{
if (I->sh_type == SHT_SYMTAB || I->sh_type == SHT_DYNSYM)
{
const ELFSectionHeader &symtab_header = *I;
user_id_t section_id = SectionIndex(I);
symbol_id += ParseSymbolTable(symbol_table, symbol_id,
&symtab_header, section_id);
}
}
// Synthesize trampoline symbols to help navigate the PLT.
Section *reloc_section = PLTSection();
if (reloc_section)
{
user_id_t reloc_id = reloc_section->GetID();
const ELFSectionHeader *reloc_header = GetSectionHeaderByIndex(reloc_id);
assert(reloc_header);
ParseTrampolineSymbols(symbol_table, symbol_id, reloc_header, reloc_id);
}
return symbol_table;
}
//===----------------------------------------------------------------------===//
// Dump
//
// Dump the specifics of the runtime file container (such as any headers
// segments, sections, etc).
//----------------------------------------------------------------------
void
ObjectFileELF::Dump(Stream *s)
{
DumpELFHeader(s, m_header);
s->EOL();
DumpELFProgramHeaders(s);
s->EOL();
DumpELFSectionHeaders(s);
s->EOL();
SectionList *section_list = GetSectionList();
if (section_list)
section_list->Dump(s, NULL, true, UINT32_MAX);
Symtab *symtab = GetSymtab();
if (symtab)
symtab->Dump(s, NULL, eSortOrderNone);
s->EOL();
DumpDependentModules(s);
s->EOL();
}
//----------------------------------------------------------------------
// DumpELFHeader
//
// Dump the ELF header to the specified output stream
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFHeader(Stream *s, const ELFHeader &header)
{
s->PutCString("ELF Header\n");
s->Printf("e_ident[EI_MAG0 ] = 0x%2.2x\n", header.e_ident[EI_MAG0]);
s->Printf("e_ident[EI_MAG1 ] = 0x%2.2x '%c'\n",
header.e_ident[EI_MAG1], header.e_ident[EI_MAG1]);
s->Printf("e_ident[EI_MAG2 ] = 0x%2.2x '%c'\n",
header.e_ident[EI_MAG2], header.e_ident[EI_MAG2]);
s->Printf("e_ident[EI_MAG3 ] = 0x%2.2x '%c'\n",
header.e_ident[EI_MAG3], header.e_ident[EI_MAG3]);
s->Printf("e_ident[EI_CLASS ] = 0x%2.2x\n", header.e_ident[EI_CLASS]);
s->Printf("e_ident[EI_DATA ] = 0x%2.2x ", header.e_ident[EI_DATA]);
DumpELFHeader_e_ident_EI_DATA(s, header.e_ident[EI_DATA]);
s->Printf ("\ne_ident[EI_VERSION] = 0x%2.2x\n", header.e_ident[EI_VERSION]);
s->Printf ("e_ident[EI_PAD ] = 0x%2.2x\n", header.e_ident[EI_PAD]);
s->Printf("e_type = 0x%4.4x ", header.e_type);
DumpELFHeader_e_type(s, header.e_type);
s->Printf("\ne_machine = 0x%4.4x\n", header.e_machine);
s->Printf("e_version = 0x%8.8x\n", header.e_version);
s->Printf("e_entry = 0x%8.8" PRIx64 "\n", header.e_entry);
s->Printf("e_phoff = 0x%8.8" PRIx64 "\n", header.e_phoff);
s->Printf("e_shoff = 0x%8.8" PRIx64 "\n", header.e_shoff);
s->Printf("e_flags = 0x%8.8x\n", header.e_flags);
s->Printf("e_ehsize = 0x%4.4x\n", header.e_ehsize);
s->Printf("e_phentsize = 0x%4.4x\n", header.e_phentsize);
s->Printf("e_phnum = 0x%4.4x\n", header.e_phnum);
s->Printf("e_shentsize = 0x%4.4x\n", header.e_shentsize);
s->Printf("e_shnum = 0x%4.4x\n", header.e_shnum);
s->Printf("e_shstrndx = 0x%4.4x\n", header.e_shstrndx);
}
//----------------------------------------------------------------------
// DumpELFHeader_e_type
//
// Dump an token value for the ELF header member e_type
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFHeader_e_type(Stream *s, elf_half e_type)
{
switch (e_type)
{
case ET_NONE: *s << "ET_NONE"; break;
case ET_REL: *s << "ET_REL"; break;
case ET_EXEC: *s << "ET_EXEC"; break;
case ET_DYN: *s << "ET_DYN"; break;
case ET_CORE: *s << "ET_CORE"; break;
default:
break;
}
}
//----------------------------------------------------------------------
// DumpELFHeader_e_ident_EI_DATA
//
// Dump an token value for the ELF header member e_ident[EI_DATA]
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFHeader_e_ident_EI_DATA(Stream *s, unsigned char ei_data)
{
switch (ei_data)
{
case ELFDATANONE: *s << "ELFDATANONE"; break;
case ELFDATA2LSB: *s << "ELFDATA2LSB - Little Endian"; break;
case ELFDATA2MSB: *s << "ELFDATA2MSB - Big Endian"; break;
default:
break;
}
}
//----------------------------------------------------------------------
// DumpELFProgramHeader
//
// Dump a single ELF program header to the specified output stream
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFProgramHeader(Stream *s, const ELFProgramHeader &ph)
{
DumpELFProgramHeader_p_type(s, ph.p_type);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64 " %8.8" PRIx64, ph.p_offset, ph.p_vaddr, ph.p_paddr);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64 " %8.8x (", ph.p_filesz, ph.p_memsz, ph.p_flags);
DumpELFProgramHeader_p_flags(s, ph.p_flags);
s->Printf(") %8.8" PRIx64, ph.p_align);
}
//----------------------------------------------------------------------
// DumpELFProgramHeader_p_type
//
// Dump an token value for the ELF program header member p_type which
// describes the type of the program header
// ----------------------------------------------------------------------
void
ObjectFileELF::DumpELFProgramHeader_p_type(Stream *s, elf_word p_type)
{
const int kStrWidth = 10;
switch (p_type)
{
CASE_AND_STREAM(s, PT_NULL , kStrWidth);
CASE_AND_STREAM(s, PT_LOAD , kStrWidth);
CASE_AND_STREAM(s, PT_DYNAMIC , kStrWidth);
CASE_AND_STREAM(s, PT_INTERP , kStrWidth);
CASE_AND_STREAM(s, PT_NOTE , kStrWidth);
CASE_AND_STREAM(s, PT_SHLIB , kStrWidth);
CASE_AND_STREAM(s, PT_PHDR , kStrWidth);
default:
s->Printf("0x%8.8x%*s", p_type, kStrWidth - 10, "");
break;
}
}
//----------------------------------------------------------------------
// DumpELFProgramHeader_p_flags
//
// Dump an token value for the ELF program header member p_flags
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFProgramHeader_p_flags(Stream *s, elf_word p_flags)
{
*s << ((p_flags & PF_X) ? "PF_X" : " ")
<< (((p_flags & PF_X) && (p_flags & PF_W)) ? '+' : ' ')
<< ((p_flags & PF_W) ? "PF_W" : " ")
<< (((p_flags & PF_W) && (p_flags & PF_R)) ? '+' : ' ')
<< ((p_flags & PF_R) ? "PF_R" : " ");
}
//----------------------------------------------------------------------
// DumpELFProgramHeaders
//
// Dump all of the ELF program header to the specified output stream
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFProgramHeaders(Stream *s)
{
if (ParseProgramHeaders())
{
s->PutCString("Program Headers\n");
s->PutCString("IDX p_type p_offset p_vaddr p_paddr "
"p_filesz p_memsz p_flags p_align\n");
s->PutCString("==== ---------- -------- -------- -------- "
"-------- -------- ------------------------- --------\n");
uint32_t idx = 0;
for (ProgramHeaderCollConstIter I = m_program_headers.begin();
I != m_program_headers.end(); ++I, ++idx)
{
s->Printf("[%2u] ", idx);
ObjectFileELF::DumpELFProgramHeader(s, *I);
s->EOL();
}
}
}
//----------------------------------------------------------------------
// DumpELFSectionHeader
//
// Dump a single ELF section header to the specified output stream
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFSectionHeader(Stream *s, const ELFSectionHeader &sh)
{
s->Printf("%8.8x ", sh.sh_name);
DumpELFSectionHeader_sh_type(s, sh.sh_type);
s->Printf(" %8.8" PRIx64 " (", sh.sh_flags);
DumpELFSectionHeader_sh_flags(s, sh.sh_flags);
s->Printf(") %8.8" PRIx64 " %8.8" PRIx64 " %8.8" PRIx64, sh.sh_addr, sh.sh_offset, sh.sh_size);
s->Printf(" %8.8x %8.8x", sh.sh_link, sh.sh_info);
s->Printf(" %8.8" PRIx64 " %8.8" PRIx64, sh.sh_addralign, sh.sh_entsize);
}
//----------------------------------------------------------------------
// DumpELFSectionHeader_sh_type
//
// Dump an token value for the ELF section header member sh_type which
// describes the type of the section
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFSectionHeader_sh_type(Stream *s, elf_word sh_type)
{
const int kStrWidth = 12;
switch (sh_type)
{
CASE_AND_STREAM(s, SHT_NULL , kStrWidth);
CASE_AND_STREAM(s, SHT_PROGBITS , kStrWidth);
CASE_AND_STREAM(s, SHT_SYMTAB , kStrWidth);
CASE_AND_STREAM(s, SHT_STRTAB , kStrWidth);
CASE_AND_STREAM(s, SHT_RELA , kStrWidth);
CASE_AND_STREAM(s, SHT_HASH , kStrWidth);
CASE_AND_STREAM(s, SHT_DYNAMIC , kStrWidth);
CASE_AND_STREAM(s, SHT_NOTE , kStrWidth);
CASE_AND_STREAM(s, SHT_NOBITS , kStrWidth);
CASE_AND_STREAM(s, SHT_REL , kStrWidth);
CASE_AND_STREAM(s, SHT_SHLIB , kStrWidth);
CASE_AND_STREAM(s, SHT_DYNSYM , kStrWidth);
CASE_AND_STREAM(s, SHT_LOPROC , kStrWidth);
CASE_AND_STREAM(s, SHT_HIPROC , kStrWidth);
CASE_AND_STREAM(s, SHT_LOUSER , kStrWidth);
CASE_AND_STREAM(s, SHT_HIUSER , kStrWidth);
default:
s->Printf("0x%8.8x%*s", sh_type, kStrWidth - 10, "");
break;
}
}
//----------------------------------------------------------------------
// DumpELFSectionHeader_sh_flags
//
// Dump an token value for the ELF section header member sh_flags
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFSectionHeader_sh_flags(Stream *s, elf_xword sh_flags)
{
*s << ((sh_flags & SHF_WRITE) ? "WRITE" : " ")
<< (((sh_flags & SHF_WRITE) && (sh_flags & SHF_ALLOC)) ? '+' : ' ')
<< ((sh_flags & SHF_ALLOC) ? "ALLOC" : " ")
<< (((sh_flags & SHF_ALLOC) && (sh_flags & SHF_EXECINSTR)) ? '+' : ' ')
<< ((sh_flags & SHF_EXECINSTR) ? "EXECINSTR" : " ");
}
//----------------------------------------------------------------------
// DumpELFSectionHeaders
//
// Dump all of the ELF section header to the specified output stream
//----------------------------------------------------------------------
void
ObjectFileELF::DumpELFSectionHeaders(Stream *s)
{
if (!(ParseSectionHeaders() && GetSectionHeaderStringTable()))
return;
s->PutCString("Section Headers\n");
s->PutCString("IDX name type flags "
"addr offset size link info addralgn "
"entsize Name\n");
s->PutCString("==== -------- ------------ -------------------------------- "
"-------- -------- -------- -------- -------- -------- "
"-------- ====================\n");
uint32_t idx = 0;
for (SectionHeaderCollConstIter I = m_section_headers.begin();
I != m_section_headers.end(); ++I, ++idx)
{
s->Printf("[%2u] ", idx);
ObjectFileELF::DumpELFSectionHeader(s, *I);
const char* section_name = m_shstr_data.PeekCStr(I->sh_name);
if (section_name)
*s << ' ' << section_name << "\n";
}
}
void
ObjectFileELF::DumpDependentModules(lldb_private::Stream *s)
{
size_t num_modules = ParseDependentModules();
if (num_modules > 0)
{
s->PutCString("Dependent Modules:\n");
for (unsigned i = 0; i < num_modules; ++i)
{
const FileSpec &spec = m_filespec_ap->GetFileSpecAtIndex(i);
s->Printf(" %s\n", spec.GetFilename().GetCString());
}
}
}
bool
ObjectFileELF::GetArchitecture (ArchSpec &arch)
{
if (!ParseHeader())
return false;
arch.SetArchitecture (eArchTypeELF, m_header.e_machine, LLDB_INVALID_CPUTYPE);
arch.GetTriple().setOSName (Host::GetOSString().GetCString());
arch.GetTriple().setVendorName(Host::GetVendorString().GetCString());
return true;
}
ObjectFile::Type
ObjectFileELF::CalculateType()
{
switch (m_header.e_type)
{
case llvm::ELF::ET_NONE:
// 0 - No file type
return eTypeUnknown;
case llvm::ELF::ET_REL:
// 1 - Relocatable file
return eTypeObjectFile;
case llvm::ELF::ET_EXEC:
// 2 - Executable file
return eTypeExecutable;
case llvm::ELF::ET_DYN:
// 3 - Shared object file
return eTypeSharedLibrary;
case ET_CORE:
// 4 - Core file
return eTypeCoreFile;
default:
break;
}
return eTypeUnknown;
}
ObjectFile::Strata
ObjectFileELF::CalculateStrata()
{
switch (m_header.e_type)
{
case llvm::ELF::ET_NONE:
// 0 - No file type
return eStrataUnknown;
case llvm::ELF::ET_REL:
// 1 - Relocatable file
return eStrataUnknown;
case llvm::ELF::ET_EXEC:
// 2 - Executable file
// TODO: is there any way to detect that an executable is a kernel
// related executable by inspecting the program headers, section
// headers, symbols, or any other flag bits???
return eStrataUser;
case llvm::ELF::ET_DYN:
// 3 - Shared object file
// TODO: is there any way to detect that an shared library is a kernel
// related executable by inspecting the program headers, section
// headers, symbols, or any other flag bits???
return eStrataUnknown;
case ET_CORE:
// 4 - Core file
// TODO: is there any way to detect that an core file is a kernel
// related executable by inspecting the program headers, section
// headers, symbols, or any other flag bits???
return eStrataUnknown;
default:
break;
}
return eStrataUnknown;
}
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