1 //===- DWARFDie.cpp -------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
11 #include "SyntaxHighlighting.h"
12 #include "llvm/ADT/None.h"
13 #include "llvm/ADT/Optional.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/BinaryFormat/Dwarf.h"
16 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
17 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
18 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
19 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
20 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
21 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/DataExtractor.h"
24 #include "llvm/Support/Format.h"
25 #include "llvm/Support/MathExtras.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include <algorithm>
28 #include <cassert>
29 #include <cinttypes>
30 #include <cstdint>
31 #include <string>
32 #include <utility>
33 
34 using namespace llvm;
35 using namespace dwarf;
36 using namespace object;
37 using namespace syntax;
38 
39 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
40   OS << " (";
41   do {
42     uint64_t Shift = countTrailingZeros(Val);
43     assert(Shift < 64 && "undefined behavior");
44     uint64_t Bit = 1ULL << Shift;
45     auto PropName = ApplePropertyString(Bit);
46     if (!PropName.empty())
47       OS << PropName;
48     else
49       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
50     if (!(Val ^= Bit))
51       break;
52     OS << ", ";
53   } while (true);
54   OS << ")";
55 }
56 
57 static void dumpRanges(const DWARFObject &Obj, raw_ostream &OS,
58                        const DWARFAddressRangesVector &Ranges,
59                        unsigned AddressSize, unsigned Indent,
60                        const DIDumpOptions &DumpOpts) {
61   ArrayRef<SectionName> SectionNames;
62   if (DumpOpts.Verbose)
63     SectionNames = Obj.getSectionNames();
64 
65   for (size_t I = 0; I < Ranges.size(); ++I) {
66     const DWARFAddressRange &R = Ranges[I];
67 
68     OS << '\n';
69     OS.indent(Indent);
70     OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")", AddressSize * 2,
71                  R.LowPC, AddressSize * 2, R.HighPC);
72 
73     if (SectionNames.empty() || R.SectionIndex == -1ULL)
74       continue;
75 
76     StringRef Name = SectionNames[R.SectionIndex].Name;
77     OS << " \"" << Name << '\"';
78 
79     // Print section index if name is not unique.
80     if (!SectionNames[R.SectionIndex].IsNameUnique)
81       OS << format(" [%" PRIu64 "]", R.SectionIndex);
82   }
83 }
84 
85 static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
86                          DWARFUnit *U, unsigned Indent,
87                          DIDumpOptions DumpOpts) {
88   DWARFContext &Ctx = U->getContext();
89   const DWARFObject &Obj = Ctx.getDWARFObj();
90   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
91   if (FormValue.isFormClass(DWARFFormValue::FC_Block) ||
92       FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) {
93     ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
94     DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
95                        Ctx.isLittleEndian(), 0);
96     DWARFExpression(Data, U->getVersion(), U->getAddressByteSize())
97         .print(OS, MRI);
98     return;
99   }
100 
101   FormValue.dump(OS, DumpOpts);
102   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
103     const DWARFSection &LocSection = Obj.getLocSection();
104     const DWARFSection &LocDWOSection = Obj.getLocDWOSection();
105     uint32_t Offset = *FormValue.getAsSectionOffset();
106 
107     if (!LocSection.Data.empty()) {
108       DWARFDebugLoc DebugLoc;
109       DWARFDataExtractor Data(Obj, LocSection, Ctx.isLittleEndian(),
110                               Obj.getAddressSize());
111       auto LL = DebugLoc.parseOneLocationList(Data, &Offset);
112       if (LL)
113         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
114       else
115         OS << "error extracting location list.";
116     } else if (!LocDWOSection.Data.empty()) {
117       DataExtractor Data(LocDWOSection.Data, Ctx.isLittleEndian(), 0);
118       auto LL = DWARFDebugLocDWO::parseOneLocationList(Data, &Offset);
119       if (LL)
120         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
121       else
122         OS << "error extracting location list.";
123     }
124   }
125 }
126 
127 /// Dump the name encoded in the type tag.
128 static void dumpTypeTagName(raw_ostream &OS, dwarf::Tag T) {
129   StringRef TagStr = TagString(T);
130   if (!TagStr.startswith("DW_TAG_") || !TagStr.endswith("_type"))
131     return;
132   OS << TagStr.substr(7, TagStr.size() - 12) << " ";
133 }
134 
135 /// Recursively dump the DIE type name when applicable.
136 static void dumpTypeName(raw_ostream &OS, const DWARFDie &Die) {
137   DWARFDie D = Die.getAttributeValueAsReferencedDie(DW_AT_type);
138 
139   if (!D.isValid())
140     return;
141 
142   if (const char *Name = D.getName(DINameKind::LinkageName)) {
143     OS << Name;
144     return;
145   }
146 
147   // FIXME: We should have pretty printers per language. Currently we print
148   // everything as if it was C++ and fall back to the TAG type name.
149   const dwarf::Tag T = D.getTag();
150   switch (T) {
151   case DW_TAG_array_type:
152   case DW_TAG_pointer_type:
153   case DW_TAG_ptr_to_member_type:
154   case DW_TAG_reference_type:
155   case DW_TAG_rvalue_reference_type:
156     break;
157   default:
158     dumpTypeTagName(OS, T);
159   }
160 
161   // Follow the DW_AT_type if possible.
162   dumpTypeName(OS, D);
163 
164   switch (T) {
165   case DW_TAG_array_type:
166     OS << "[]";
167     break;
168   case DW_TAG_pointer_type:
169     OS << '*';
170     break;
171   case DW_TAG_ptr_to_member_type:
172     OS << '*';
173     break;
174   case DW_TAG_reference_type:
175     OS << '&';
176     break;
177   case DW_TAG_rvalue_reference_type:
178     OS << "&&";
179     break;
180   default:
181     break;
182   }
183 }
184 
185 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
186                           uint32_t *OffsetPtr, dwarf::Attribute Attr,
187                           dwarf::Form Form, unsigned Indent,
188                           DIDumpOptions DumpOpts) {
189   if (!Die.isValid())
190     return;
191   const char BaseIndent[] = "            ";
192   OS << BaseIndent;
193   OS.indent(Indent + 2);
194   auto attrString = AttributeString(Attr);
195   if (!attrString.empty())
196     WithColor(OS, syntax::Attribute) << attrString;
197   else
198     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", Attr);
199 
200   if (DumpOpts.Verbose || DumpOpts.ShowForm) {
201     auto formString = FormEncodingString(Form);
202     if (!formString.empty())
203       OS << " [" << formString << ']';
204     else
205       OS << format(" [DW_FORM_Unknown_%x]", Form);
206   }
207 
208   DWARFUnit *U = Die.getDwarfUnit();
209   DWARFFormValue formValue(Form);
210 
211   if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr, U))
212     return;
213 
214   OS << "\t(";
215 
216   StringRef Name;
217   std::string File;
218   auto Color = syntax::Enumerator;
219   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
220     Color = syntax::String;
221     if (const auto *LT = U->getContext().getLineTableForUnit(U))
222       if (LT->getFileNameByIndex(
223               formValue.getAsUnsignedConstant().getValue(),
224               U->getCompilationDir(),
225               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
226         File = '"' + File + '"';
227         Name = File;
228       }
229   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
230     Name = AttributeValueString(Attr, *Val);
231 
232   if (!Name.empty())
233     WithColor(OS, Color) << Name;
234   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
235     OS << *formValue.getAsUnsignedConstant();
236   else if (Attr == DW_AT_location || Attr == DW_AT_frame_base ||
237            Attr == DW_AT_data_member_location ||
238            Attr == DW_AT_GNU_call_site_value)
239     dumpLocation(OS, formValue, U, sizeof(BaseIndent) + Indent + 4, DumpOpts);
240   else
241     formValue.dump(OS, DumpOpts);
242 
243   // We have dumped the attribute raw value. For some attributes
244   // having both the raw value and the pretty-printed value is
245   // interesting. These attributes are handled below.
246   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
247     if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(
248             DINameKind::LinkageName))
249       OS << " \"" << Name << '\"';
250   } else if (Attr == DW_AT_type) {
251     OS << " \"";
252     dumpTypeName(OS, Die);
253     OS << '"';
254   } else if (Attr == DW_AT_APPLE_property_attribute) {
255     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
256       dumpApplePropertyAttribute(OS, *OptVal);
257   } else if (Attr == DW_AT_ranges) {
258     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
259     dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
260                sizeof(BaseIndent) + Indent + 4, DumpOpts);
261   }
262 
263   OS << ")\n";
264 }
265 
266 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
267 
268 bool DWARFDie::isSubroutineDIE() const {
269   auto Tag = getTag();
270   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
271 }
272 
273 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
274   if (!isValid())
275     return None;
276   auto AbbrevDecl = getAbbreviationDeclarationPtr();
277   if (AbbrevDecl)
278     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
279   return None;
280 }
281 
282 Optional<DWARFFormValue>
283 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
284   if (!isValid())
285     return None;
286   auto AbbrevDecl = getAbbreviationDeclarationPtr();
287   if (AbbrevDecl) {
288     for (auto Attr : Attrs) {
289       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
290         return Value;
291     }
292   }
293   return None;
294 }
295 
296 Optional<DWARFFormValue>
297 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
298   if (!isValid())
299     return None;
300   auto Die = *this;
301   if (auto Value = Die.find(Attrs))
302     return Value;
303   if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
304     Die = D;
305   if (auto Value = Die.find(Attrs))
306     return Value;
307   if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
308     Die = D;
309   if (auto Value = Die.find(Attrs))
310     return Value;
311   return None;
312 }
313 
314 DWARFDie
315 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
316   if (auto SpecRef = toReference(find(Attr))) {
317     if (auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef))
318       return SpecUnit->getDIEForOffset(*SpecRef);
319   }
320   return DWARFDie();
321 }
322 
323 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
324   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
325 }
326 
327 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
328   if (auto FormValue = find(DW_AT_high_pc)) {
329     if (auto Address = FormValue->getAsAddress()) {
330       // High PC is an address.
331       return Address;
332     }
333     if (auto Offset = FormValue->getAsUnsignedConstant()) {
334       // High PC is an offset from LowPC.
335       return LowPC + *Offset;
336     }
337   }
338   return None;
339 }
340 
341 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
342                                uint64_t &SectionIndex) const {
343   auto F = find(DW_AT_low_pc);
344   auto LowPcAddr = toAddress(F);
345   if (!LowPcAddr)
346     return false;
347   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
348     LowPC = *LowPcAddr;
349     HighPC = *HighPcAddr;
350     SectionIndex = F->getSectionIndex();
351     return true;
352   }
353   return false;
354 }
355 
356 DWARFAddressRangesVector DWARFDie::getAddressRanges() const {
357   if (isNULL())
358     return DWARFAddressRangesVector();
359   // Single range specified by low/high PC.
360   uint64_t LowPC, HighPC, Index;
361   if (getLowAndHighPC(LowPC, HighPC, Index))
362     return {{LowPC, HighPC, Index}};
363 
364   // Multiple ranges from .debug_ranges section.
365   auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
366   if (RangesOffset) {
367     DWARFDebugRangeList RangeList;
368     if (U->extractRangeList(*RangesOffset, RangeList))
369       return RangeList.getAbsoluteRanges(U->getBaseAddress());
370   }
371   return DWARFAddressRangesVector();
372 }
373 
374 void DWARFDie::collectChildrenAddressRanges(
375     DWARFAddressRangesVector &Ranges) const {
376   if (isNULL())
377     return;
378   if (isSubprogramDIE()) {
379     const auto &DIERanges = getAddressRanges();
380     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
381   }
382 
383   for (auto Child : children())
384     Child.collectChildrenAddressRanges(Ranges);
385 }
386 
387 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
388   for (const auto &R : getAddressRanges()) {
389     if (R.LowPC <= Address && Address < R.HighPC)
390       return true;
391   }
392   return false;
393 }
394 
395 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
396   if (!isSubroutineDIE())
397     return nullptr;
398   return getName(Kind);
399 }
400 
401 const char *DWARFDie::getName(DINameKind Kind) const {
402   if (!isValid() || Kind == DINameKind::None)
403     return nullptr;
404   // Try to get mangled name only if it was asked for.
405   if (Kind == DINameKind::LinkageName) {
406     if (auto Name = dwarf::toString(
407             findRecursively({DW_AT_MIPS_linkage_name, DW_AT_linkage_name}),
408             nullptr))
409       return Name;
410   }
411   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
412     return Name;
413   return nullptr;
414 }
415 
416 uint64_t DWARFDie::getDeclLine() const {
417   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
418 }
419 
420 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
421                               uint32_t &CallColumn,
422                               uint32_t &CallDiscriminator) const {
423   CallFile = toUnsigned(find(DW_AT_call_file), 0);
424   CallLine = toUnsigned(find(DW_AT_call_line), 0);
425   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
426   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
427 }
428 
429 /// Helper to dump a DIE with all of its parents, but no siblings.
430 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
431                                 DIDumpOptions DumpOpts) {
432   if (!Die)
433     return Indent;
434   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts);
435   Die.dump(OS, Indent, DumpOpts);
436   return Indent + 2;
437 }
438 
439 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
440                     DIDumpOptions DumpOpts) const {
441   if (!isValid())
442     return;
443   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
444   const uint32_t Offset = getOffset();
445   uint32_t offset = Offset;
446   if (DumpOpts.ShowParents) {
447     DumpOpts.ShowParents = false;
448     Indent = dumpParentChain(getParent(), OS, Indent, DumpOpts);
449   }
450 
451   if (debug_info_data.isValidOffset(offset)) {
452     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
453     WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
454 
455     if (abbrCode) {
456       auto AbbrevDecl = getAbbreviationDeclarationPtr();
457       if (AbbrevDecl) {
458         auto tagString = TagString(getTag());
459         if (!tagString.empty())
460           WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
461         else
462           WithColor(OS, syntax::Tag).get().indent(Indent)
463               << format("DW_TAG_Unknown_%x", getTag());
464 
465         if (DumpOpts.Verbose)
466           OS << format(" [%u] %c", abbrCode,
467                        AbbrevDecl->hasChildren() ? '*' : ' ');
468         OS << '\n';
469 
470         // Dump all data in the DIE for the attributes.
471         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
472           if (AttrSpec.Form == DW_FORM_implicit_const) {
473             // We are dumping .debug_info section ,
474             // implicit_const attribute values are not really stored here,
475             // but in .debug_abbrev section. So we just skip such attrs.
476             continue;
477           }
478           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
479                         Indent, DumpOpts);
480         }
481 
482         DWARFDie child = getFirstChild();
483         if (DumpOpts.RecurseDepth > 0 && child) {
484           DumpOpts.RecurseDepth--;
485           while (child) {
486             child.dump(OS, Indent + 2, DumpOpts);
487             child = child.getSibling();
488           }
489         }
490       } else {
491         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
492            << abbrCode << '\n';
493       }
494     } else {
495       OS.indent(Indent) << "NULL\n";
496     }
497   }
498 }
499 
500 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
501 
502 DWARFDie DWARFDie::getParent() const {
503   if (isValid())
504     return U->getParent(Die);
505   return DWARFDie();
506 }
507 
508 DWARFDie DWARFDie::getSibling() const {
509   if (isValid())
510     return U->getSibling(Die);
511   return DWARFDie();
512 }
513 
514 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
515   return make_range(attribute_iterator(*this, false),
516                     attribute_iterator(*this, true));
517 }
518 
519 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
520     : Die(D), AttrValue(0), Index(0) {
521   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
522   assert(AbbrDecl && "Must have abbreviation declaration");
523   if (End) {
524     // This is the end iterator so we set the index to the attribute count.
525     Index = AbbrDecl->getNumAttributes();
526   } else {
527     // This is the begin iterator so we extract the value for this->Index.
528     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
529     updateForIndex(*AbbrDecl, 0);
530   }
531 }
532 
533 void DWARFDie::attribute_iterator::updateForIndex(
534     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
535   Index = I;
536   // AbbrDecl must be valid before calling this function.
537   auto NumAttrs = AbbrDecl.getNumAttributes();
538   if (Index < NumAttrs) {
539     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
540     // Add the previous byte size of any previous attribute value.
541     AttrValue.Offset += AttrValue.ByteSize;
542     AttrValue.Value.setForm(AbbrDecl.getFormByIndex(Index));
543     uint32_t ParseOffset = AttrValue.Offset;
544     auto U = Die.getDwarfUnit();
545     assert(U && "Die must have valid DWARF unit");
546     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
547                                           &ParseOffset, U);
548     (void)b;
549     assert(b && "extractValue cannot fail on fully parsed DWARF");
550     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
551   } else {
552     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
553     AttrValue.clear();
554   }
555 }
556 
557 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
558   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
559     updateForIndex(*AbbrDecl, Index + 1);
560   return *this;
561 }
562