llvm-6502/lib/DebugInfo/DWARFUnit.cpp
2013-09-23 23:15:57 +00:00

393 lines
13 KiB
C++

//===-- DWARFUnit.cpp -----------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "DWARFUnit.h"
#include "DWARFContext.h"
#include "llvm/DebugInfo/DWARFFormValue.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/Path.h"
#include <cstdio>
using namespace llvm;
using namespace dwarf;
DWARFUnit::DWARFUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef AS,
StringRef RS, StringRef SS, StringRef SOS, StringRef AOS,
const RelocAddrMap *M, bool LE)
: Abbrev(DA), InfoSection(IS), AbbrevSection(AS), RangeSection(RS),
StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
RelocMap(M), isLittleEndian(LE) {
clear();
}
DWARFUnit::~DWARFUnit() {
}
bool DWARFUnit::getAddrOffsetSectionItem(uint32_t Index,
uint64_t &Result) const {
uint32_t Offset = AddrOffsetSectionBase + Index * AddrSize;
if (AddrOffsetSection.size() < Offset + AddrSize)
return false;
DataExtractor DA(AddrOffsetSection, isLittleEndian, AddrSize);
Result = DA.getAddress(&Offset);
return true;
}
bool DWARFUnit::getStringOffsetSectionItem(uint32_t Index,
uint32_t &Result) const {
// FIXME: string offset section entries are 8-byte for DWARF64.
const uint32_t ItemSize = 4;
uint32_t Offset = Index * ItemSize;
if (StringOffsetSection.size() < Offset + ItemSize)
return false;
DataExtractor DA(StringOffsetSection, isLittleEndian, 0);
Result = DA.getU32(&Offset);
return true;
}
bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
Length = debug_info.getU32(offset_ptr);
Version = debug_info.getU16(offset_ptr);
uint64_t abbrOffset = debug_info.getU32(offset_ptr);
AddrSize = debug_info.getU8(offset_ptr);
bool lengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
bool versionOK = DWARFContext::isSupportedVersion(Version);
bool abbrOffsetOK = AbbrevSection.size() > abbrOffset;
bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
if (!lengthOK || !versionOK || !addrSizeOK || !abbrOffsetOK)
return false;
Abbrevs = Abbrev->getAbbreviationDeclarationSet(abbrOffset);
return true;
}
bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
clear();
Offset = *offset_ptr;
if (debug_info.isValidOffset(*offset_ptr)) {
if (extractImpl(debug_info, offset_ptr))
return true;
// reset the offset to where we tried to parse from if anything went wrong
*offset_ptr = Offset;
}
return false;
}
uint32_t
DWARFUnit::extract(uint32_t offset, DataExtractor debug_info_data,
const DWARFAbbreviationDeclarationSet *abbrevs) {
clear();
Offset = offset;
if (debug_info_data.isValidOffset(offset)) {
Length = debug_info_data.getU32(&offset);
Version = debug_info_data.getU16(&offset);
bool abbrevsOK = debug_info_data.getU32(&offset) == abbrevs->getOffset();
Abbrevs = abbrevs;
AddrSize = debug_info_data.getU8(&offset);
bool versionOK = DWARFContext::isSupportedVersion(Version);
bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
if (versionOK && addrSizeOK && abbrevsOK &&
debug_info_data.isValidOffset(offset))
return offset;
}
return 0;
}
bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
DWARFDebugRangeList &RangeList) const {
// Require that compile unit is extracted.
assert(DieArray.size() > 0);
DataExtractor RangesData(RangeSection, isLittleEndian, AddrSize);
uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
return RangeList.extract(RangesData, &ActualRangeListOffset);
}
void DWARFUnit::clear() {
Offset = 0;
Length = 0;
Version = 0;
Abbrevs = 0;
AddrSize = 0;
BaseAddr = 0;
RangeSectionBase = 0;
AddrOffsetSectionBase = 0;
clearDIEs(false);
DWO.reset();
}
const char *DWARFUnit::getCompilationDir() {
extractDIEsIfNeeded(true);
if (DieArray.empty())
return 0;
return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
}
uint64_t DWARFUnit::getDWOId() {
extractDIEsIfNeeded(true);
const uint64_t FailValue = -1ULL;
if (DieArray.empty())
return FailValue;
return DieArray[0]
.getAttributeValueAsUnsigned(this, DW_AT_GNU_dwo_id, FailValue);
}
void DWARFUnit::setDIERelations() {
if (DieArray.empty())
return;
DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
DWARFDebugInfoEntryMinimal *curr_die;
// We purposely are skipping the last element in the array in the loop below
// so that we can always have a valid next item
for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
// Since our loop doesn't include the last element, we can always
// safely access the next die in the array.
DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
const DWARFAbbreviationDeclaration *curr_die_abbrev =
curr_die->getAbbreviationDeclarationPtr();
if (curr_die_abbrev) {
// Normal DIE
if (curr_die_abbrev->hasChildren())
next_die->setParent(curr_die);
else
curr_die->setSibling(next_die);
} else {
// NULL DIE that terminates a sibling chain
DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
if (parent)
parent->setSibling(next_die);
}
}
// Since we skipped the last element, we need to fix it up!
if (die_array_begin < die_array_end)
curr_die->setParent(die_array_begin);
}
void DWARFUnit::extractDIEsToVector(
bool AppendCUDie, bool AppendNonCUDies,
std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
if (!AppendCUDie && !AppendNonCUDies)
return;
// Set the offset to that of the first DIE and calculate the start of the
// next compilation unit header.
uint32_t Offset = getFirstDIEOffset();
uint32_t NextCUOffset = getNextUnitOffset();
DWARFDebugInfoEntryMinimal DIE;
uint32_t Depth = 0;
const uint8_t *FixedFormSizes =
DWARFFormValue::getFixedFormSizes(getAddressByteSize(), getVersion());
bool IsCUDie = true;
while (Offset < NextCUOffset &&
DIE.extractFast(this, FixedFormSizes, &Offset)) {
if (IsCUDie) {
if (AppendCUDie)
Dies.push_back(DIE);
if (!AppendNonCUDies)
break;
// The average bytes per DIE entry has been seen to be
// around 14-20 so let's pre-reserve the needed memory for
// our DIE entries accordingly.
Dies.reserve(Dies.size() + getDebugInfoSize() / 14);
IsCUDie = false;
} else {
Dies.push_back(DIE);
}
const DWARFAbbreviationDeclaration *AbbrDecl =
DIE.getAbbreviationDeclarationPtr();
if (AbbrDecl) {
// Normal DIE
if (AbbrDecl->hasChildren())
++Depth;
} else {
// NULL DIE.
if (Depth > 0)
--Depth;
if (Depth == 0)
break; // We are done with this compile unit!
}
}
// Give a little bit of info if we encounter corrupt DWARF (our offset
// should always terminate at or before the start of the next compilation
// unit header).
if (Offset > NextCUOffset)
fprintf(stderr, "warning: DWARF compile unit extends beyond its "
"bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), Offset);
}
size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
if ((CUDieOnly && DieArray.size() > 0) ||
DieArray.size() > 1)
return 0; // Already parsed.
bool HasCUDie = DieArray.size() > 0;
extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);
if (DieArray.empty())
return 0;
// If CU DIE was just parsed, copy several attribute values from it.
if (!HasCUDie) {
uint64_t BaseAddr =
DieArray[0].getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
if (BaseAddr == -1U)
BaseAddr = DieArray[0].getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
setBaseAddress(BaseAddr);
AddrOffsetSectionBase =
DieArray[0].getAttributeValueAsReference(this, DW_AT_GNU_addr_base, 0);
RangeSectionBase =
DieArray[0].getAttributeValueAsReference(this, DW_AT_GNU_ranges_base, 0);
}
setDIERelations();
return DieArray.size();
}
DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
: DWOFile(DWOFile),
DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
DWOU(0) {
if (DWOContext->getNumDWOCompileUnits() > 0)
DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
}
bool DWARFUnit::parseDWO() {
if (DWO.get() != 0)
return false;
extractDIEsIfNeeded(true);
if (DieArray.empty())
return false;
const char *DWOFileName =
DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, 0);
if (DWOFileName == 0)
return false;
const char *CompilationDir =
DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
SmallString<16> AbsolutePath;
if (sys::path::is_relative(DWOFileName) && CompilationDir != 0) {
sys::path::append(AbsolutePath, CompilationDir);
}
sys::path::append(AbsolutePath, DWOFileName);
object::ObjectFile *DWOFile =
object::ObjectFile::createObjectFile(AbsolutePath);
if (!DWOFile)
return false;
// Reset DWOHolder.
DWO.reset(new DWOHolder(DWOFile));
DWARFUnit *DWOCU = DWO->getUnit();
// Verify that compile unit in .dwo file is valid.
if (DWOCU == 0 || DWOCU->getDWOId() != getDWOId()) {
DWO.reset();
return false;
}
// Share .debug_addr and .debug_ranges section with compile unit in .dwo
DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
DWOCU->setRangesSection(RangeSection, RangeSectionBase);
return true;
}
void DWARFUnit::clearDIEs(bool KeepCUDie) {
if (DieArray.size() > (unsigned)KeepCUDie) {
// std::vectors never get any smaller when resized to a smaller size,
// or when clear() or erase() are called, the size will report that it
// is smaller, but the memory allocated remains intact (call capacity()
// to see this). So we need to create a temporary vector and swap the
// contents which will cause just the internal pointers to be swapped
// so that when temporary vector goes out of scope, it will destroy the
// contents.
std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
DieArray.swap(TmpArray);
// Save at least the compile unit DIE
if (KeepCUDie)
DieArray.push_back(TmpArray.front());
}
}
void
DWARFUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
bool clear_dies_if_already_not_parsed,
uint32_t CUOffsetInAranges) {
// This function is usually called if there in no .debug_aranges section
// in order to produce a compile unit level set of address ranges that
// is accurate. If the DIEs weren't parsed, then we don't want all dies for
// all compile units to stay loaded when they weren't needed. So we can end
// up parsing the DWARF and then throwing them all away to keep memory usage
// down.
const bool clear_dies = extractDIEsIfNeeded(false) > 1 &&
clear_dies_if_already_not_parsed;
DieArray[0].buildAddressRangeTable(this, debug_aranges, CUOffsetInAranges);
bool DWOCreated = parseDWO();
if (DWO.get()) {
// If there is a .dwo file for this compile unit, then skeleton CU DIE
// doesn't have children, and we should instead build address range table
// from DIEs in the .debug_info.dwo section of .dwo file.
DWO->getUnit()->buildAddressRangeTable(
debug_aranges, clear_dies_if_already_not_parsed, CUOffsetInAranges);
}
if (DWOCreated && clear_dies_if_already_not_parsed)
DWO.reset();
// Keep memory down by clearing DIEs if this generate function
// caused them to be parsed.
if (clear_dies)
clearDIEs(true);
}
const DWARFDebugInfoEntryMinimal *
DWARFUnit::getSubprogramForAddress(uint64_t Address) {
extractDIEsIfNeeded(false);
for (size_t i = 0, n = DieArray.size(); i != n; i++)
if (DieArray[i].isSubprogramDIE() &&
DieArray[i].addressRangeContainsAddress(this, Address)) {
return &DieArray[i];
}
return 0;
}
DWARFDebugInfoEntryInlinedChain
DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
// First, find a subprogram that contains the given address (the root
// of inlined chain).
const DWARFUnit *ChainCU = 0;
const DWARFDebugInfoEntryMinimal *SubprogramDIE =
getSubprogramForAddress(Address);
if (SubprogramDIE) {
ChainCU = this;
} else {
// Try to look for subprogram DIEs in the DWO file.
parseDWO();
if (DWO.get()) {
SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address);
if (SubprogramDIE)
ChainCU = DWO->getUnit();
}
}
// Get inlined chain rooted at this subprogram DIE.
if (!SubprogramDIE)
return DWARFDebugInfoEntryInlinedChain();
return SubprogramDIE->getInlinedChainForAddress(ChainCU, Address);
}