Files
clang-p2996/lldb/source/Core/Section.cpp
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

614 lines
20 KiB
C++

//===-- Section.cpp ---------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lldb/Core/Section.h"
#include "lldb/Core/Address.h" // for Address
#include "lldb/Core/Module.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/FileSpec.h" // for FileSpec
#include "lldb/Utility/Stream.h" // for Stream
#include "lldb/Utility/VMRange.h" // for VMRange
#include <inttypes.h> // for PRIx64
#include <limits> // for numeric_limits
#include <utility> // for distance
namespace lldb_private {
class DataExtractor;
}
using namespace lldb;
using namespace lldb_private;
static const char *GetSectionTypeAsCString(lldb::SectionType sect_type) {
switch (sect_type) {
case eSectionTypeInvalid:
return "invalid";
case eSectionTypeCode:
return "code";
case eSectionTypeContainer:
return "container";
case eSectionTypeData:
return "data";
case eSectionTypeDataCString:
return "data-cstr";
case eSectionTypeDataCStringPointers:
return "data-cstr-ptr";
case eSectionTypeDataSymbolAddress:
return "data-symbol-addr";
case eSectionTypeData4:
return "data-4-byte";
case eSectionTypeData8:
return "data-8-byte";
case eSectionTypeData16:
return "data-16-byte";
case eSectionTypeDataPointers:
return "data-ptrs";
case eSectionTypeDebug:
return "debug";
case eSectionTypeZeroFill:
return "zero-fill";
case eSectionTypeDataObjCMessageRefs:
return "objc-message-refs";
case eSectionTypeDataObjCCFStrings:
return "objc-cfstrings";
case eSectionTypeDWARFDebugAbbrev:
return "dwarf-abbrev";
case eSectionTypeDWARFDebugAddr:
return "dwarf-addr";
case eSectionTypeDWARFDebugAranges:
return "dwarf-aranges";
case eSectionTypeDWARFDebugCuIndex:
return "dwarf-cu-index";
case eSectionTypeDWARFDebugFrame:
return "dwarf-frame";
case eSectionTypeDWARFDebugInfo:
return "dwarf-info";
case eSectionTypeDWARFDebugLine:
return "dwarf-line";
case eSectionTypeDWARFDebugLoc:
return "dwarf-loc";
case eSectionTypeDWARFDebugMacInfo:
return "dwarf-macinfo";
case eSectionTypeDWARFDebugMacro:
return "dwarf-macro";
case eSectionTypeDWARFDebugPubNames:
return "dwarf-pubnames";
case eSectionTypeDWARFDebugPubTypes:
return "dwarf-pubtypes";
case eSectionTypeDWARFDebugRanges:
return "dwarf-ranges";
case eSectionTypeDWARFDebugStr:
return "dwarf-str";
case eSectionTypeDWARFDebugStrOffsets:
return "dwarf-str-offsets";
case eSectionTypeELFSymbolTable:
return "elf-symbol-table";
case eSectionTypeELFDynamicSymbols:
return "elf-dynamic-symbols";
case eSectionTypeELFRelocationEntries:
return "elf-relocation-entries";
case eSectionTypeELFDynamicLinkInfo:
return "elf-dynamic-link-info";
case eSectionTypeDWARFAppleNames:
return "apple-names";
case eSectionTypeDWARFAppleTypes:
return "apple-types";
case eSectionTypeDWARFAppleNamespaces:
return "apple-namespaces";
case eSectionTypeDWARFAppleObjC:
return "apple-objc";
case eSectionTypeEHFrame:
return "eh-frame";
case eSectionTypeARMexidx:
return "ARM.exidx";
case eSectionTypeARMextab:
return "ARM.extab";
case eSectionTypeCompactUnwind:
return "compact-unwind";
case eSectionTypeGoSymtab:
return "go-symtab";
case eSectionTypeAbsoluteAddress:
return "absolute";
case eSectionTypeOther:
return "regular";
}
return "unknown";
}
Section::Section(const ModuleSP &module_sp, ObjectFile *obj_file,
user_id_t sect_id, const ConstString &name,
SectionType sect_type, addr_t file_addr, addr_t byte_size,
lldb::offset_t file_offset, lldb::offset_t file_size,
uint32_t log2align, uint32_t flags,
uint32_t target_byte_size /*=1*/)
: ModuleChild(module_sp), UserID(sect_id), Flags(flags),
m_obj_file(obj_file), m_type(sect_type), m_parent_wp(), m_name(name),
m_file_addr(file_addr), m_byte_size(byte_size),
m_file_offset(file_offset), m_file_size(file_size),
m_log2align(log2align), m_children(), m_fake(false), m_encrypted(false),
m_thread_specific(false), m_readable(false), m_writable(false),
m_executable(false), m_relocated(false), m_target_byte_size(target_byte_size) {
// printf ("Section::Section(%p): module=%p, sect_id = 0x%16.16" PRIx64 ",
// addr=[0x%16.16" PRIx64 " - 0x%16.16" PRIx64 "), file [0x%16.16" PRIx64 "
// - 0x%16.16" PRIx64 "), flags = 0x%8.8x, name = %s\n",
// this, module_sp.get(), sect_id, file_addr, file_addr +
// byte_size, file_offset, file_offset + file_size, flags,
// name.GetCString());
}
Section::Section(const lldb::SectionSP &parent_section_sp,
const ModuleSP &module_sp, ObjectFile *obj_file,
user_id_t sect_id, const ConstString &name,
SectionType sect_type, addr_t file_addr, addr_t byte_size,
lldb::offset_t file_offset, lldb::offset_t file_size,
uint32_t log2align, uint32_t flags,
uint32_t target_byte_size /*=1*/)
: ModuleChild(module_sp), UserID(sect_id), Flags(flags),
m_obj_file(obj_file), m_type(sect_type), m_parent_wp(), m_name(name),
m_file_addr(file_addr), m_byte_size(byte_size),
m_file_offset(file_offset), m_file_size(file_size),
m_log2align(log2align), m_children(), m_fake(false), m_encrypted(false),
m_thread_specific(false), m_readable(false), m_writable(false),
m_executable(false), m_relocated(false), m_target_byte_size(target_byte_size) {
// printf ("Section::Section(%p): module=%p, sect_id = 0x%16.16" PRIx64 ",
// addr=[0x%16.16" PRIx64 " - 0x%16.16" PRIx64 "), file [0x%16.16" PRIx64 "
// - 0x%16.16" PRIx64 "), flags = 0x%8.8x, name = %s.%s\n",
// this, module_sp.get(), sect_id, file_addr, file_addr +
// byte_size, file_offset, file_offset + file_size, flags,
// parent_section_sp->GetName().GetCString(), name.GetCString());
if (parent_section_sp)
m_parent_wp = parent_section_sp;
}
Section::~Section() {
// printf ("Section::~Section(%p)\n", this);
}
addr_t Section::GetFileAddress() const {
SectionSP parent_sp(GetParent());
if (parent_sp) {
// This section has a parent which means m_file_addr is an offset into
// the parent section, so the file address for this section is the file
// address of the parent plus the offset
return parent_sp->GetFileAddress() + m_file_addr;
}
// This section has no parent, so m_file_addr is the file base address
return m_file_addr;
}
bool Section::SetFileAddress(lldb::addr_t file_addr) {
SectionSP parent_sp(GetParent());
if (parent_sp) {
if (m_file_addr >= file_addr)
return parent_sp->SetFileAddress(m_file_addr - file_addr);
return false;
} else {
// This section has no parent, so m_file_addr is the file base address
m_file_addr = file_addr;
return true;
}
}
lldb::addr_t Section::GetOffset() const {
// This section has a parent which means m_file_addr is an offset.
SectionSP parent_sp(GetParent());
if (parent_sp)
return m_file_addr;
// This section has no parent, so there is no offset to be had
return 0;
}
addr_t Section::GetLoadBaseAddress(Target *target) const {
addr_t load_base_addr = LLDB_INVALID_ADDRESS;
SectionSP parent_sp(GetParent());
if (parent_sp) {
load_base_addr = parent_sp->GetLoadBaseAddress(target);
if (load_base_addr != LLDB_INVALID_ADDRESS)
load_base_addr += GetOffset();
}
if (load_base_addr == LLDB_INVALID_ADDRESS) {
load_base_addr = target->GetSectionLoadList().GetSectionLoadAddress(
const_cast<Section *>(this)->shared_from_this());
}
return load_base_addr;
}
bool Section::ResolveContainedAddress(addr_t offset, Address &so_addr,
bool allow_section_end) const {
const size_t num_children = m_children.GetSize();
for (size_t i = 0; i < num_children; i++) {
Section *child_section = m_children.GetSectionAtIndex(i).get();
addr_t child_offset = child_section->GetOffset();
if (child_offset <= offset &&
offset - child_offset <
child_section->GetByteSize() + (allow_section_end ? 1 : 0))
return child_section->ResolveContainedAddress(offset - child_offset,
so_addr, allow_section_end);
}
so_addr.SetOffset(offset);
so_addr.SetSection(const_cast<Section *>(this)->shared_from_this());
#ifdef LLDB_CONFIGURATION_DEBUG
// For debug builds, ensure that there are no orphaned (i.e., moduleless)
// sections.
assert(GetModule().get());
#endif
return true;
}
bool Section::ContainsFileAddress(addr_t vm_addr) const {
const addr_t file_addr = GetFileAddress();
if (file_addr != LLDB_INVALID_ADDRESS) {
if (file_addr <= vm_addr) {
const addr_t offset = (vm_addr - file_addr) * m_target_byte_size;
return offset < GetByteSize();
}
}
return false;
}
int Section::Compare(const Section &a, const Section &b) {
if (&a == &b)
return 0;
const ModuleSP a_module_sp = a.GetModule();
const ModuleSP b_module_sp = b.GetModule();
if (a_module_sp == b_module_sp) {
user_id_t a_sect_uid = a.GetID();
user_id_t b_sect_uid = b.GetID();
if (a_sect_uid < b_sect_uid)
return -1;
if (a_sect_uid > b_sect_uid)
return 1;
return 0;
} else {
// The modules are different, just compare the module pointers
if (a_module_sp.get() < b_module_sp.get())
return -1;
else
return 1; // We already know the modules aren't equal
}
}
void Section::Dump(Stream *s, Target *target, uint32_t depth) const {
// s->Printf("%.*p: ", (int)sizeof(void*) * 2, this);
s->Indent();
s->Printf("0x%8.8" PRIx64 " %-16s ", GetID(),
GetSectionTypeAsCString(m_type));
bool resolved = true;
addr_t addr = LLDB_INVALID_ADDRESS;
if (GetByteSize() == 0)
s->Printf("%39s", "");
else {
if (target)
addr = GetLoadBaseAddress(target);
if (addr == LLDB_INVALID_ADDRESS) {
if (target)
resolved = false;
addr = GetFileAddress();
}
VMRange range(addr, addr + m_byte_size);
range.Dump(s, 0);
}
s->Printf("%c %c%c%c 0x%8.8" PRIx64 " 0x%8.8" PRIx64 " 0x%8.8x ",
resolved ? ' ' : '*', m_readable ? 'r' : '-',
m_writable ? 'w' : '-', m_executable ? 'x' : '-', m_file_offset,
m_file_size, Get());
DumpName(s);
s->EOL();
if (depth > 0)
m_children.Dump(s, target, false, depth - 1);
}
void Section::DumpName(Stream *s) const {
SectionSP parent_sp(GetParent());
if (parent_sp) {
parent_sp->DumpName(s);
s->PutChar('.');
} else {
// The top most section prints the module basename
const char *name = NULL;
ModuleSP module_sp(GetModule());
const FileSpec &file_spec = m_obj_file->GetFileSpec();
if (m_obj_file)
name = file_spec.GetFilename().AsCString();
if ((!name || !name[0]) && module_sp)
name = module_sp->GetFileSpec().GetFilename().AsCString();
if (name && name[0])
s->Printf("%s.", name);
}
m_name.Dump(s);
}
bool Section::IsDescendant(const Section *section) {
if (this == section)
return true;
SectionSP parent_sp(GetParent());
if (parent_sp)
return parent_sp->IsDescendant(section);
return false;
}
bool Section::Slide(addr_t slide_amount, bool slide_children) {
if (m_file_addr != LLDB_INVALID_ADDRESS) {
if (slide_amount == 0)
return true;
m_file_addr += slide_amount;
if (slide_children)
m_children.Slide(slide_amount, slide_children);
return true;
}
return false;
}
//------------------------------------------------------------------
/// Get the permissions as OR'ed bits from lldb::Permissions
//------------------------------------------------------------------
uint32_t Section::GetPermissions() const {
uint32_t permissions = 0;
if (m_readable)
permissions |= ePermissionsReadable;
if (m_writable)
permissions |= ePermissionsWritable;
if (m_executable)
permissions |= ePermissionsExecutable;
return permissions;
}
//------------------------------------------------------------------
/// Set the permissions using bits OR'ed from lldb::Permissions
//------------------------------------------------------------------
void Section::SetPermissions(uint32_t permissions) {
m_readable = (permissions & ePermissionsReadable) != 0;
m_writable = (permissions & ePermissionsWritable) != 0;
m_executable = (permissions & ePermissionsExecutable) != 0;
}
lldb::offset_t Section::GetSectionData(void *dst, lldb::offset_t dst_len,
lldb::offset_t offset) {
if (m_obj_file)
return m_obj_file->ReadSectionData(this, offset, dst, dst_len);
return 0;
}
lldb::offset_t Section::GetSectionData(DataExtractor &section_data) {
if (m_obj_file)
return m_obj_file->ReadSectionData(this, section_data);
return 0;
}
#pragma mark SectionList
SectionList::SectionList() : m_sections() {}
SectionList::~SectionList() {}
SectionList &SectionList::operator=(const SectionList &rhs) {
if (this != &rhs)
m_sections = rhs.m_sections;
return *this;
}
size_t SectionList::AddSection(const lldb::SectionSP &section_sp) {
if (section_sp) {
size_t section_index = m_sections.size();
m_sections.push_back(section_sp);
return section_index;
}
return std::numeric_limits<size_t>::max();
}
// Warning, this can be slow as it's removing items from a std::vector.
bool SectionList::DeleteSection(size_t idx) {
if (idx < m_sections.size()) {
m_sections.erase(m_sections.begin() + idx);
return true;
}
return false;
}
size_t SectionList::FindSectionIndex(const Section *sect) {
iterator sect_iter;
iterator begin = m_sections.begin();
iterator end = m_sections.end();
for (sect_iter = begin; sect_iter != end; ++sect_iter) {
if (sect_iter->get() == sect) {
// The secton was already in this section list
return std::distance(begin, sect_iter);
}
}
return UINT32_MAX;
}
size_t SectionList::AddUniqueSection(const lldb::SectionSP &sect_sp) {
size_t sect_idx = FindSectionIndex(sect_sp.get());
if (sect_idx == UINT32_MAX) {
sect_idx = AddSection(sect_sp);
}
return sect_idx;
}
bool SectionList::ReplaceSection(user_id_t sect_id,
const lldb::SectionSP &sect_sp,
uint32_t depth) {
iterator sect_iter, end = m_sections.end();
for (sect_iter = m_sections.begin(); sect_iter != end; ++sect_iter) {
if ((*sect_iter)->GetID() == sect_id) {
*sect_iter = sect_sp;
return true;
} else if (depth > 0) {
if ((*sect_iter)
->GetChildren()
.ReplaceSection(sect_id, sect_sp, depth - 1))
return true;
}
}
return false;
}
size_t SectionList::GetNumSections(uint32_t depth) const {
size_t count = m_sections.size();
if (depth > 0) {
const_iterator sect_iter, end = m_sections.end();
for (sect_iter = m_sections.begin(); sect_iter != end; ++sect_iter) {
count += (*sect_iter)->GetChildren().GetNumSections(depth - 1);
}
}
return count;
}
SectionSP SectionList::GetSectionAtIndex(size_t idx) const {
SectionSP sect_sp;
if (idx < m_sections.size())
sect_sp = m_sections[idx];
return sect_sp;
}
SectionSP
SectionList::FindSectionByName(const ConstString &section_dstr) const {
SectionSP sect_sp;
// Check if we have a valid section string
if (section_dstr && !m_sections.empty()) {
const_iterator sect_iter;
const_iterator end = m_sections.end();
for (sect_iter = m_sections.begin();
sect_iter != end && sect_sp.get() == NULL; ++sect_iter) {
Section *child_section = sect_iter->get();
if (child_section) {
if (child_section->GetName() == section_dstr) {
sect_sp = *sect_iter;
} else {
sect_sp =
child_section->GetChildren().FindSectionByName(section_dstr);
}
}
}
}
return sect_sp;
}
SectionSP SectionList::FindSectionByID(user_id_t sect_id) const {
SectionSP sect_sp;
if (sect_id) {
const_iterator sect_iter;
const_iterator end = m_sections.end();
for (sect_iter = m_sections.begin();
sect_iter != end && sect_sp.get() == NULL; ++sect_iter) {
if ((*sect_iter)->GetID() == sect_id) {
sect_sp = *sect_iter;
break;
} else {
sect_sp = (*sect_iter)->GetChildren().FindSectionByID(sect_id);
}
}
}
return sect_sp;
}
SectionSP SectionList::FindSectionByType(SectionType sect_type,
bool check_children,
size_t start_idx) const {
SectionSP sect_sp;
size_t num_sections = m_sections.size();
for (size_t idx = start_idx; idx < num_sections; ++idx) {
if (m_sections[idx]->GetType() == sect_type) {
sect_sp = m_sections[idx];
break;
} else if (check_children) {
sect_sp = m_sections[idx]->GetChildren().FindSectionByType(
sect_type, check_children, 0);
if (sect_sp)
break;
}
}
return sect_sp;
}
SectionSP SectionList::FindSectionContainingFileAddress(addr_t vm_addr,
uint32_t depth) const {
SectionSP sect_sp;
const_iterator sect_iter;
const_iterator end = m_sections.end();
for (sect_iter = m_sections.begin();
sect_iter != end && sect_sp.get() == NULL; ++sect_iter) {
Section *sect = sect_iter->get();
if (sect->ContainsFileAddress(vm_addr)) {
// The file address is in this section. We need to make sure one of our
// child
// sections doesn't contain this address as well as obeying the depth
// limit
// that was passed in.
if (depth > 0)
sect_sp = sect->GetChildren().FindSectionContainingFileAddress(
vm_addr, depth - 1);
if (sect_sp.get() == NULL && !sect->IsFake())
sect_sp = *sect_iter;
}
}
return sect_sp;
}
bool SectionList::ContainsSection(user_id_t sect_id) const {
return FindSectionByID(sect_id).get() != NULL;
}
void SectionList::Dump(Stream *s, Target *target, bool show_header,
uint32_t depth) const {
bool target_has_loaded_sections =
target && !target->GetSectionLoadList().IsEmpty();
if (show_header && !m_sections.empty()) {
s->Indent();
s->Printf("SectID Type %s Address "
" Perm File Off. File Size Flags "
" Section Name\n",
target_has_loaded_sections ? "Load" : "File");
s->Indent();
s->PutCString("---------- ---------------- "
"--------------------------------------- ---- ---------- "
"---------- "
"---------- ----------------------------\n");
}
const_iterator sect_iter;
const_iterator end = m_sections.end();
for (sect_iter = m_sections.begin(); sect_iter != end; ++sect_iter) {
(*sect_iter)->Dump(s, target_has_loaded_sections ? target : NULL, depth);
}
if (show_header && !m_sections.empty())
s->IndentLess();
}
size_t SectionList::Slide(addr_t slide_amount, bool slide_children) {
size_t count = 0;
const_iterator pos, end = m_sections.end();
for (pos = m_sections.begin(); pos != end; ++pos) {
if ((*pos)->Slide(slide_amount, slide_children))
++count;
}
return count;
}