261 lines · cpp
1//===-- DWARFDebugInfo.cpp ------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "SymbolFileDWARF.h"10 11#include <algorithm>12#include <set>13 14#include "lldb/Host/PosixApi.h"15#include "lldb/Symbol/ObjectFile.h"16#include "lldb/Utility/RegularExpression.h"17#include "lldb/Utility/Stream.h"18#include "llvm/Support/Casting.h"19 20#include "DWARFCompileUnit.h"21#include "DWARFContext.h"22#include "DWARFDebugAranges.h"23#include "DWARFDebugInfo.h"24#include "DWARFDebugInfoEntry.h"25#include "DWARFFormValue.h"26#include "DWARFTypeUnit.h"27#include "LogChannelDWARF.h"28 29using namespace lldb;30using namespace lldb_private;31using namespace lldb_private::plugin::dwarf;32 33// Constructor34DWARFDebugInfo::DWARFDebugInfo(SymbolFileDWARF &dwarf, DWARFContext &context)35 : m_dwarf(dwarf), m_context(context), m_units(), m_cu_aranges_up() {}36 37const DWARFDebugAranges &DWARFDebugInfo::GetCompileUnitAranges() {38 if (m_cu_aranges_up)39 return *m_cu_aranges_up;40 41 m_cu_aranges_up = std::make_unique<DWARFDebugAranges>();42 const DWARFDataExtractor &debug_aranges_data =43 m_context.getOrLoadArangesData();44 45 // Extract what we can from the .debug_aranges first.46 m_cu_aranges_up->extract(debug_aranges_data);47 48 // Make a list of all CUs represented by the .debug_aranges data.49 std::set<dw_offset_t> cus_with_data;50 for (size_t n = 0; n < m_cu_aranges_up->GetNumRanges(); n++) {51 dw_offset_t offset = m_cu_aranges_up->OffsetAtIndex(n);52 if (offset != DW_INVALID_OFFSET)53 cus_with_data.insert(offset);54 }55 56 // Manually build arange data for everything that wasn't in .debug_aranges.57 // The .debug_aranges accelerator is not guaranteed to be complete.58 // Tools such as dsymutil can provide stronger guarantees than required by the59 // standard. Without that guarantee, we have to iterate over every CU in the60 // .debug_info and make sure there's a corresponding entry in the table and if61 // not, add one for every subprogram.62 ObjectFile *OF = m_dwarf.GetObjectFile();63 if (!OF || !OF->CanTrustAddressRanges()) {64 const size_t num_units = GetNumUnits();65 for (size_t idx = 0; idx < num_units; ++idx) {66 DWARFUnit *cu = GetUnitAtIndex(idx);67 68 dw_offset_t offset = cu->GetOffset();69 if (cus_with_data.find(offset) == cus_with_data.end())70 cu->BuildAddressRangeTable(m_cu_aranges_up.get());71 }72 }73 74 const bool minimize = true;75 m_cu_aranges_up->Sort(minimize);76 return *m_cu_aranges_up;77}78 79void DWARFDebugInfo::ParseUnitsFor(DIERef::Section section) {80 DWARFDataExtractor data = section == DIERef::Section::DebugTypes81 ? m_context.getOrLoadDebugTypesData()82 : m_context.getOrLoadDebugInfoData();83 lldb::offset_t offset = 0;84 while (data.ValidOffset(offset)) {85 const lldb::offset_t unit_header_offset = offset;86 llvm::Expected<DWARFUnitSP> expected_unit_sp =87 DWARFUnit::extract(m_dwarf, m_units.size(), data, section, &offset);88 89 if (!expected_unit_sp) {90 Log *log = GetLog(DWARFLog::DebugInfo);91 if (log)92 LLDB_LOG(log, "Unable to extract DWARFUnitHeader at {0:x}: {1}",93 unit_header_offset,94 llvm::toString(expected_unit_sp.takeError()));95 else96 llvm::consumeError(expected_unit_sp.takeError());97 return;98 }99 100 DWARFUnitSP unit_sp = *expected_unit_sp;101 102 // If it didn't return an error, then it should be returning a valid Unit.103 assert((bool)unit_sp);104 105 // Keep a map of DWO ID back to the skeleton units. Sometimes accelerator106 // table lookups can cause the DWO files to be accessed before the skeleton107 // compile unit is parsed, so we keep a map to allow us to match up the DWO108 // file to the back to the skeleton compile units.109 if (unit_sp->GetUnitType() == llvm::dwarf::DW_UT_skeleton) {110 if (std::optional<uint64_t> unit_dwo_id = unit_sp->GetHeaderDWOId())111 m_dwarf5_dwo_id_to_skeleton_unit[*unit_dwo_id] = unit_sp.get();112 }113 114 m_units.push_back(unit_sp);115 offset = unit_sp->GetNextUnitOffset();116 117 if (auto *type_unit = llvm::dyn_cast<DWARFTypeUnit>(unit_sp.get())) {118 m_type_hash_to_unit_index.emplace_back(type_unit->GetTypeHash(),119 unit_sp->GetID());120 }121 }122}123 124DWARFUnit *DWARFDebugInfo::GetSkeletonUnit(DWARFUnit *dwo_unit) {125 // If this isn't a DWO unit, don't try and find the skeleton unit.126 if (!dwo_unit->IsDWOUnit())127 return nullptr;128 129 auto dwo_id = dwo_unit->GetDWOId();130 if (!dwo_id.has_value())131 return nullptr;132 133 // Parse the unit headers so that m_dwarf5_dwo_id_to_skeleton_unit is filled134 // in with all of the DWARF5 skeleton compile units DWO IDs since it is easy135 // to access the DWO IDs in the DWARFUnitHeader for each DWARFUnit.136 ParseUnitHeadersIfNeeded();137 138 // Find the value in our cache and return it we we find it. This cache may139 // only contain DWARF5 units.140 auto iter = m_dwarf5_dwo_id_to_skeleton_unit.find(*dwo_id);141 if (iter != m_dwarf5_dwo_id_to_skeleton_unit.end())142 return iter->second;143 144 // DWARF5 unit headers have the DWO ID and should have already been in the map145 // so if it wasn't found in the above find() call, then we didn't find it and146 // don't need to do the more expensive DWARF4 search.147 if (dwo_unit->GetVersion() >= 5)148 return nullptr;149 150 // Parse all DWO IDs from all DWARF4 and earlier compile units that have DWO151 // IDs. It is more expensive to get the DWO IDs from DWARF4 compile units as152 // we need to parse the unit DIE and extract the DW_AT_dwo_id or153 // DW_AT_GNU_dwo_id attribute values, so do this only if we didn't find our154 // match above search and only for DWARF4 and earlier compile units.155 llvm::call_once(m_dwarf4_dwo_id_to_skeleton_unit_once_flag, [this]() {156 for (uint32_t i = 0, num = GetNumUnits(); i < num; ++i) {157 if (DWARFUnit *unit = GetUnitAtIndex(i)) {158 if (unit->GetVersion() < 5) {159 if (std::optional<uint64_t> unit_dwo_id = unit->GetDWOId())160 m_dwarf4_dwo_id_to_skeleton_unit[*unit_dwo_id] = unit;161 }162 }163 }164 });165 166 // Search the DWARF4 DWO results that we parsed lazily.167 iter = m_dwarf4_dwo_id_to_skeleton_unit.find(*dwo_id);168 if (iter != m_dwarf4_dwo_id_to_skeleton_unit.end())169 return iter->second;170 return nullptr;171}172 173void DWARFDebugInfo::ParseUnitHeadersIfNeeded() {174 llvm::call_once(m_units_once_flag, [&] {175 ParseUnitsFor(DIERef::Section::DebugInfo);176 ParseUnitsFor(DIERef::Section::DebugTypes);177 llvm::sort(m_type_hash_to_unit_index, llvm::less_first());178 });179}180 181size_t DWARFDebugInfo::GetNumUnits() {182 ParseUnitHeadersIfNeeded();183 return m_units.size();184}185 186DWARFUnit *DWARFDebugInfo::GetUnitAtIndex(size_t idx) {187 DWARFUnit *cu = nullptr;188 if (idx < GetNumUnits())189 cu = m_units[idx].get();190 return cu;191}192 193uint32_t DWARFDebugInfo::FindUnitIndex(DIERef::Section section,194 dw_offset_t offset) {195 ParseUnitHeadersIfNeeded();196 197 // llvm::lower_bound is not used as for DIE offsets it would still return198 // index +1 and GetOffset() returning index itself would be a special case.199 auto pos = llvm::upper_bound(200 m_units, std::make_pair(section, offset),201 [](const std::pair<DIERef::Section, dw_offset_t> &lhs,202 const DWARFUnitSP &rhs) {203 return lhs < std::make_pair(rhs->GetDebugSection(), rhs->GetOffset());204 });205 uint32_t idx = std::distance(m_units.begin(), pos);206 if (idx == 0)207 return DW_INVALID_INDEX;208 return idx - 1;209}210 211DWARFUnit *DWARFDebugInfo::GetUnitAtOffset(DIERef::Section section,212 dw_offset_t cu_offset,213 uint32_t *idx_ptr) {214 uint32_t idx = FindUnitIndex(section, cu_offset);215 DWARFUnit *result = GetUnitAtIndex(idx);216 if (result && result->GetOffset() != cu_offset) {217 result = nullptr;218 idx = DW_INVALID_INDEX;219 }220 if (idx_ptr)221 *idx_ptr = idx;222 return result;223}224 225DWARFUnit *226DWARFDebugInfo::GetUnitContainingDIEOffset(DIERef::Section section,227 dw_offset_t die_offset) {228 uint32_t idx = FindUnitIndex(section, die_offset);229 DWARFUnit *result = GetUnitAtIndex(idx);230 if (result && !result->ContainsDIEOffset(die_offset))231 return nullptr;232 return result;233}234 235const std::shared_ptr<SymbolFileDWARFDwo> &DWARFDebugInfo::GetDwpSymbolFile() {236 return m_dwarf.GetDwpSymbolFile();237}238 239DWARFTypeUnit *DWARFDebugInfo::GetTypeUnitForHash(uint64_t hash) {240 auto pos = llvm::lower_bound(m_type_hash_to_unit_index,241 std::make_pair(hash, 0u), llvm::less_first());242 if (pos == m_type_hash_to_unit_index.end() || pos->first != hash)243 return nullptr;244 return llvm::cast<DWARFTypeUnit>(GetUnitAtIndex(pos->second));245}246 247bool DWARFDebugInfo::ContainsTypeUnits() {248 ParseUnitHeadersIfNeeded();249 return !m_type_hash_to_unit_index.empty();250}251 252// GetDIE()253//254// Get the DIE (Debug Information Entry) with the specified offset.255DWARFDIE256DWARFDebugInfo::GetDIE(DIERef::Section section, dw_offset_t die_offset) {257 if (DWARFUnit *cu = GetUnitContainingDIEOffset(section, die_offset))258 return cu->GetNonSkeletonUnit().GetDIE(die_offset);259 return DWARFDIE(); // Not found260}261