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 AS,
21 StringRef RS, StringRef SS, StringRef SOS, StringRef AOS,
22 const RelocAddrMap *M, bool LE)
23 : Abbrev(DA), InfoSection(IS), AbbrevSection(AS), RangeSection(RS),
24 StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
25 RelocMap(M), isLittleEndian(LE) {
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 abbrOffsetOK = AbbrevSection.size() > abbrOffset;
63 bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
65 if (!lengthOK || !versionOK || !addrSizeOK || !abbrOffsetOK)
68 Abbrevs = Abbrev->getAbbreviationDeclarationSet(abbrOffset);
72 bool DWARFUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
77 if (debug_info.isValidOffset(*offset_ptr)) {
78 if (extractImpl(debug_info, offset_ptr))
81 // reset the offset to where we tried to parse from if anything went wrong
88 bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
89 DWARFDebugRangeList &RangeList) const {
90 // Require that compile unit is extracted.
91 assert(DieArray.size() > 0);
92 DataExtractor RangesData(RangeSection, isLittleEndian, AddrSize);
93 uint32_t ActualRangeListOffset = RangeSectionBase + RangeListOffset;
94 return RangeList.extract(RangesData, &ActualRangeListOffset);
97 void DWARFUnit::clear() {
104 RangeSectionBase = 0;
105 AddrOffsetSectionBase = 0;
110 const char *DWARFUnit::getCompilationDir() {
111 extractDIEsIfNeeded(true);
112 if (DieArray.empty())
114 return DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
117 uint64_t DWARFUnit::getDWOId() {
118 extractDIEsIfNeeded(true);
119 const uint64_t FailValue = -1ULL;
120 if (DieArray.empty())
123 .getAttributeValueAsUnsignedConstant(this, DW_AT_GNU_dwo_id, FailValue);
126 void DWARFUnit::setDIERelations() {
127 if (DieArray.empty())
129 DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
130 DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
131 DWARFDebugInfoEntryMinimal *curr_die;
132 // We purposely are skipping the last element in the array in the loop below
133 // so that we can always have a valid next item
134 for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
135 // Since our loop doesn't include the last element, we can always
136 // safely access the next die in the array.
137 DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
139 const DWARFAbbreviationDeclaration *curr_die_abbrev =
140 curr_die->getAbbreviationDeclarationPtr();
142 if (curr_die_abbrev) {
144 if (curr_die_abbrev->hasChildren())
145 next_die->setParent(curr_die);
147 curr_die->setSibling(next_die);
149 // NULL DIE that terminates a sibling chain
150 DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
152 parent->setSibling(next_die);
156 // Since we skipped the last element, we need to fix it up!
157 if (die_array_begin < die_array_end)
158 curr_die->setParent(die_array_begin);
161 void DWARFUnit::extractDIEsToVector(
162 bool AppendCUDie, bool AppendNonCUDies,
163 std::vector<DWARFDebugInfoEntryMinimal> &Dies) const {
164 if (!AppendCUDie && !AppendNonCUDies)
167 // Set the offset to that of the first DIE and calculate the start of the
168 // next compilation unit header.
169 uint32_t Offset = getFirstDIEOffset();
170 uint32_t NextCUOffset = getNextUnitOffset();
171 DWARFDebugInfoEntryMinimal DIE;
175 while (Offset < NextCUOffset && DIE.extractFast(this, &Offset)) {
179 if (!AppendNonCUDies)
181 // The average bytes per DIE entry has been seen to be
182 // around 14-20 so let's pre-reserve the needed memory for
183 // our DIE entries accordingly.
184 Dies.reserve(Dies.size() + getDebugInfoSize() / 14);
190 const DWARFAbbreviationDeclaration *AbbrDecl =
191 DIE.getAbbreviationDeclarationPtr();
194 if (AbbrDecl->hasChildren())
201 break; // We are done with this compile unit!
205 // Give a little bit of info if we encounter corrupt DWARF (our offset
206 // should always terminate at or before the start of the next compilation
208 if (Offset > NextCUOffset)
209 fprintf(stderr, "warning: DWARF compile unit extends beyond its "
210 "bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), Offset);
213 size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
214 if ((CUDieOnly && DieArray.size() > 0) ||
216 return 0; // Already parsed.
218 bool HasCUDie = DieArray.size() > 0;
219 extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);
221 if (DieArray.empty())
224 // If CU DIE was just parsed, copy several attribute values from it.
227 DieArray[0].getAttributeValueAsAddress(this, DW_AT_low_pc, -1ULL);
228 if (BaseAddr == -1ULL)
229 BaseAddr = DieArray[0].getAttributeValueAsAddress(this, DW_AT_entry_pc, 0);
230 setBaseAddress(BaseAddr);
231 AddrOffsetSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
232 this, DW_AT_GNU_addr_base, 0);
233 RangeSectionBase = DieArray[0].getAttributeValueAsSectionOffset(
234 this, DW_AT_GNU_ranges_base, 0);
238 return DieArray.size();
241 DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
243 DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
245 if (DWOContext->getNumDWOCompileUnits() > 0)
246 DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
249 bool DWARFUnit::parseDWO() {
252 extractDIEsIfNeeded(true);
253 if (DieArray.empty())
255 const char *DWOFileName =
256 DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
259 const char *CompilationDir =
260 DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
261 SmallString<16> AbsolutePath;
262 if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
263 sys::path::append(AbsolutePath, CompilationDir);
265 sys::path::append(AbsolutePath, DWOFileName);
266 ErrorOr<object::ObjectFile *> DWOFile =
267 object::ObjectFile::createObjectFile(AbsolutePath);
271 DWO.reset(new DWOHolder(DWOFile.get()));
272 DWARFUnit *DWOCU = DWO->getUnit();
273 // Verify that compile unit in .dwo file is valid.
274 if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
278 // Share .debug_addr and .debug_ranges section with compile unit in .dwo
279 DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
280 DWOCU->setRangesSection(RangeSection, RangeSectionBase);
284 void DWARFUnit::clearDIEs(bool KeepCUDie) {
285 if (DieArray.size() > (unsigned)KeepCUDie) {
286 // std::vectors never get any smaller when resized to a smaller size,
287 // or when clear() or erase() are called, the size will report that it
288 // is smaller, but the memory allocated remains intact (call capacity()
289 // to see this). So we need to create a temporary vector and swap the
290 // contents which will cause just the internal pointers to be swapped
291 // so that when temporary vector goes out of scope, it will destroy the
293 std::vector<DWARFDebugInfoEntryMinimal> TmpArray;
294 DieArray.swap(TmpArray);
295 // Save at least the compile unit DIE
297 DieArray.push_back(TmpArray.front());
301 void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
302 // First, check if CU DIE describes address ranges for the unit.
303 const auto &CUDIERanges = getCompileUnitDIE()->getAddressRanges(this);
304 if (!CUDIERanges.empty()) {
305 CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
309 // This function is usually called if there in no .debug_aranges section
310 // in order to produce a compile unit level set of address ranges that
311 // is accurate. If the DIEs weren't parsed, then we don't want all dies for
312 // all compile units to stay loaded when they weren't needed. So we can end
313 // up parsing the DWARF and then throwing them all away to keep memory usage
315 const bool ClearDIEs = extractDIEsIfNeeded(false) > 1;
316 DieArray[0].collectChildrenAddressRanges(this, CURanges);
318 // Collect address ranges from DIEs in .dwo if necessary.
319 bool DWOCreated = parseDWO();
321 DWO->getUnit()->collectAddressRanges(CURanges);
325 // Keep memory down by clearing DIEs if this generate function
326 // caused them to be parsed.
331 const DWARFDebugInfoEntryMinimal *
332 DWARFUnit::getSubprogramForAddress(uint64_t Address) {
333 extractDIEsIfNeeded(false);
334 for (const DWARFDebugInfoEntryMinimal &DIE : DieArray) {
335 if (DIE.isSubprogramDIE() &&
336 DIE.addressRangeContainsAddress(this, Address)) {
343 DWARFDebugInfoEntryInlinedChain
344 DWARFUnit::getInlinedChainForAddress(uint64_t Address) {
345 // First, find a subprogram that contains the given address (the root
346 // of inlined chain).
347 const DWARFUnit *ChainCU = nullptr;
348 const DWARFDebugInfoEntryMinimal *SubprogramDIE =
349 getSubprogramForAddress(Address);
353 // Try to look for subprogram DIEs in the DWO file.
356 SubprogramDIE = DWO->getUnit()->getSubprogramForAddress(Address);
358 ChainCU = DWO->getUnit();
362 // Get inlined chain rooted at this subprogram DIE.
364 return DWARFDebugInfoEntryInlinedChain();
365 return SubprogramDIE->getInlinedChainForAddress(ChainCU, Address);