1 //===-- DWARFUnit.cpp -----------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "DWARFUnit.h"
11 #include "DWARFContext.h"
12 #include "llvm/DebugInfo/DWARFFormValue.h"
13 #include "llvm/Support/Dwarf.h"
14 #include "llvm/Support/Path.h"
18 using namespace dwarf;
20 DWARFUnit::DWARFUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef RS,
21 StringRef SS, StringRef SOS, StringRef AOS,
22 const RelocAddrMap *M, bool LE)
23 : Abbrev(DA), InfoSection(IS), RangeSection(RS), StringSection(SS),
24 StringOffsetSection(SOS), AddrOffsetSection(AOS), RelocMap(M),
29 DWARFUnit::~DWARFUnit() {
32 bool DWARFUnit::getAddrOffsetSectionItem(uint32_t Index,
33 uint64_t &Result) const {
34 uint32_t Offset = AddrOffsetSectionBase + Index * AddrSize;
35 if (AddrOffsetSection.size() < Offset + AddrSize)
37 DataExtractor DA(AddrOffsetSection, isLittleEndian, AddrSize);
38 Result = DA.getAddress(&Offset);
42 bool DWARFUnit::getStringOffsetSectionItem(uint32_t Index,
43 uint32_t &Result) const {
44 // FIXME: string offset section entries are 8-byte for DWARF64.
45 const uint32_t ItemSize = 4;
46 uint32_t Offset = Index * ItemSize;
47 if (StringOffsetSection.size() < Offset + ItemSize)
49 DataExtractor DA(StringOffsetSection, isLittleEndian, 0);
50 Result = DA.getU32(&Offset);
54 bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
55 Length = debug_info.getU32(offset_ptr);
56 Version = debug_info.getU16(offset_ptr);
57 uint64_t AbbrOffset = debug_info.getU32(offset_ptr);
58 AddrSize = debug_info.getU8(offset_ptr);
60 bool LengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
61 bool VersionOK = DWARFContext::isSupportedVersion(Version);
62 bool AddrSizeOK = AddrSize == 4 || AddrSize == 8;
64 if (!LengthOK || !VersionOK || !AddrSizeOK)
67 Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
68 if (Abbrevs == nullptr)
74 bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
79 if (debug_info.isValidOffset(*offset_ptr)) {
80 if (extractImpl(debug_info, offset_ptr))
83 // reset the offset to where we tried to parse from if anything went wrong
90 bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
91 DWARFDebugRangeList &RangeList) const {
92 // Require that compile unit is extracted.
93 assert(DieArray.size() > 0);
94 DataExtractor RangesData(RangeSection, isLittleEndian, AddrSize);
95 uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
96 return RangeList.extract(RangesData, &ActualRangeListOffset);
99 void DWARFUnit::clear() {
106 RangeSectionBase = 0;
107 AddrOffsetSectionBase = 0;
112 const char *DWARFUnit::getCompilationDir() {
113 extractDIEsIfNeeded(true);
114 if (DieArray.empty())
116 return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
119 uint64_t DWARFUnit::getDWOId() {
120 extractDIEsIfNeeded(true);
121 const uint64_t FailValue = -1ULL;
122 if (DieArray.empty())
125 .getAttributeValueAsUnsignedConstant(this, DW_AT_GNU_dwo_id, FailValue);
128 void DWARFUnit::setDIERelations() {
129 if (DieArray.empty())
131 DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
132 DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
133 DWARFDebugInfoEntryMinimal *curr_die;
134 // We purposely are skipping the last element in the array in the loop below
135 // so that we can always have a valid next item
136 for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
137 // Since our loop doesn't include the last element, we can always
138 // safely access the next die in the array.
139 DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
141 const DWARFAbbreviationDeclaration *curr_die_abbrev =
142 curr_die->getAbbreviationDeclarationPtr();
144 if (curr_die_abbrev) {
146 if (curr_die_abbrev->hasChildren())
147 next_die->setParent(curr_die);
149 curr_die->setSibling(next_die);
151 // NULL DIE that terminates a sibling chain
152 DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
154 parent->setSibling(next_die);
158 // Since we skipped the last element, we need to fix it up!
159 if (die_array_begin < die_array_end)
160 curr_die->setParent(die_array_begin);
163 void DWARFUnit::extractDIEsToVector(
164 bool AppendCUDie, bool AppendNonCUDies,
165 std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
166 if (!AppendCUDie && !AppendNonCUDies)
169 // Set the offset to that of the first DIE and calculate the start of the
170 // next compilation unit header.
171 uint32_t DIEOffset = Offset + getHeaderSize();
172 uint32_t NextCUOffset = getNextUnitOffset();
173 DWARFDebugInfoEntryMinimal DIE;
177 while (DIEOffset < NextCUOffset && DIE.extractFast(this, &DIEOffset)) {
181 if (!AppendNonCUDies)
183 // The average bytes per DIE entry has been seen to be
184 // around 14-20 so let's pre-reserve the needed memory for
185 // our DIE entries accordingly.
186 Dies.reserve(Dies.size() + getDebugInfoSize() / 14);
192 const DWARFAbbreviationDeclaration *AbbrDecl =
193 DIE.getAbbreviationDeclarationPtr();
196 if (AbbrDecl->hasChildren())
203 break; // We are done with this compile unit!
207 // Give a little bit of info if we encounter corrupt DWARF (our offset
208 // should always terminate at or before the start of the next compilation
210 if (DIEOffset > NextCUOffset)
211 fprintf(stderr, "warning: DWARF compile unit extends beyond its "
212 "bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), DIEOffset);
215 size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
216 if ((CUDieOnly && DieArray.size() > 0) ||
218 return 0; // Already parsed.
220 bool HasCUDie = DieArray.size() > 0;
221 extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);
223 if (DieArray.empty())
226 // If CU DIE was just parsed, copy several attribute values from it.
229 DieArray[0].getAttributeValueAsAddress(this, DW_AT_low_pc, -1ULL);
230 if (BaseAddr == -1ULL)
231 BaseAddr = DieArray[0].getAttributeValueAsAddress(this, DW_AT_entry_pc, 0);
232 setBaseAddress(BaseAddr);
233 AddrOffsetSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
234 this, DW_AT_GNU_addr_base, 0);
235 RangeSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
236 this, DW_AT_GNU_ranges_base, 0);
240 return DieArray.size();
243 DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
245 DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
247 if (DWOContext->getNumDWOCompileUnits() > 0)
248 DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
251 bool DWARFUnit::parseDWO() {
254 extractDIEsIfNeeded(true);
255 if (DieArray.empty())
257 const char *DWOFileName =
258 DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
261 const char *CompilationDir =
262 DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
263 SmallString<16> AbsolutePath;
264 if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
265 sys::path::append(AbsolutePath, CompilationDir);
267 sys::path::append(AbsolutePath, DWOFileName);
268 ErrorOr<object::ObjectFile *> DWOFile =
269 object::ObjectFile::createObjectFile(AbsolutePath);
273 DWO.reset(new DWOHolder(DWOFile.get()));
274 DWARFUnit *DWOCU = DWO->getUnit();
275 // Verify that compile unit in .dwo file is valid.
276 if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
280 // Share .debug_addr and .debug_ranges section with compile unit in .dwo
281 DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
282 DWOCU->setRangesSection(RangeSection, RangeSectionBase);
286 void DWARFUnit::clearDIEs(bool KeepCUDie) {
287 if (DieArray.size() > (unsigned)KeepCUDie) {
288 // std::vectors never get any smaller when resized to a smaller size,
289 // or when clear() or erase() are called, the size will report that it
290 // is smaller, but the memory allocated remains intact (call capacity()
291 // to see this). So we need to create a temporary vector and swap the
292 // contents which will cause just the internal pointers to be swapped
293 // so that when temporary vector goes out of scope, it will destroy the
295 std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
296 DieArray.swap(TmpArray);
297 // Save at least the compile unit DIE
299 DieArray.push_back(TmpArray.front());
303 void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
304 // First, check if CU DIE describes address ranges for the unit.
305 const auto &CUDIERanges = getCompileUnitDIE()->getAddressRanges(this);
306 if (!CUDIERanges.empty()) {
307 CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
311 // This function is usually called if there in no .debug_aranges section
312 // in order to produce a compile unit level set of address ranges that
313 // is accurate. If the DIEs weren't parsed, then we don't want all dies for
314 // all compile units to stay loaded when they weren't needed. So we can end
315 // up parsing the DWARF and then throwing them all away to keep memory usage
317 const bool ClearDIEs = extractDIEsIfNeeded(false) > 1;
318 DieArray[0].collectChildrenAddressRanges(this, CURanges);
320 // Collect address ranges from DIEs in .dwo if necessary.
321 bool DWOCreated = parseDWO();
323 DWO->getUnit()->collectAddressRanges(CURanges);
327 // Keep memory down by clearing DIEs if this generate function
328 // caused them to be parsed.
333 const DWARFDebugInfoEntryMinimal *
334 DWARFUnit::getSubprogramForAddress(uint64_t Address) {
335 extractDIEsIfNeeded(false);
336 for (const DWARFDebugInfoEntryMinimal &DIE : DieArray) {
337 if (DIE.isSubprogramDIE() &&
338 DIE.addressRangeContainsAddress(this, Address)) {
345 DWARFDebugInfoEntryInlinedChain
346 DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
347 // First, find a subprogram that contains the given address (the root
348 // of inlined chain).
349 const DWARFUnit *ChainCU = nullptr;
350 const DWARFDebugInfoEntryMinimal *SubprogramDIE =
351 getSubprogramForAddress(Address);
355 // Try to look for subprogram DIEs in the DWO file.
358 SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address);
360 ChainCU = DWO->getUnit();
364 // Get inlined chain rooted at this subprogram DIE.
366 return DWARFDebugInfoEntryInlinedChain();
367 return SubprogramDIE->getInlinedChainForAddress(ChainCU, Address);