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,
212                               U->getFormParams(), U))
213     return;
214 
215   OS << "\t(";
216 
217   StringRef Name;
218   std::string File;
219   auto Color = syntax::Enumerator;
220   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
221     Color = syntax::String;
222     if (const auto *LT = U->getContext().getLineTableForUnit(U))
223       if (LT->getFileNameByIndex(
224               formValue.getAsUnsignedConstant().getValue(),
225               U->getCompilationDir(),
226               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
227         File = '"' + File + '"';
228         Name = File;
229       }
230   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
231     Name = AttributeValueString(Attr, *Val);
232 
233   if (!Name.empty())
234     WithColor(OS, Color) << Name;
235   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
236     OS << *formValue.getAsUnsignedConstant();
237   else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
238            formValue.getAsUnsignedConstant()) {
239     if (DumpOpts.ShowAddresses) {
240       // Print the actual address rather than the offset.
241       uint64_t LowPC, HighPC, Index;
242       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
243         OS << format("0x%016" PRIx64, HighPC);
244       else
245         formValue.dump(OS, DumpOpts);
246     }
247   } else if (Attr == DW_AT_location || Attr == DW_AT_frame_base ||
248              Attr == DW_AT_data_member_location ||
249              Attr == DW_AT_GNU_call_site_value)
250     dumpLocation(OS, formValue, U, sizeof(BaseIndent) + Indent + 4, DumpOpts);
251   else
252     formValue.dump(OS, DumpOpts);
253 
254   // We have dumped the attribute raw value. For some attributes
255   // having both the raw value and the pretty-printed value is
256   // interesting. These attributes are handled below.
257   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
258     if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(
259             DINameKind::LinkageName))
260       OS << " \"" << Name << '\"';
261   } else if (Attr == DW_AT_type) {
262     OS << " \"";
263     dumpTypeName(OS, Die);
264     OS << '"';
265   } else if (Attr == DW_AT_APPLE_property_attribute) {
266     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
267       dumpApplePropertyAttribute(OS, *OptVal);
268   } else if (Attr == DW_AT_ranges) {
269     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
270     dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
271                sizeof(BaseIndent) + Indent + 4, DumpOpts);
272   }
273 
274   OS << ")\n";
275 }
276 
277 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
278 
279 bool DWARFDie::isSubroutineDIE() const {
280   auto Tag = getTag();
281   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
282 }
283 
284 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
285   if (!isValid())
286     return None;
287   auto AbbrevDecl = getAbbreviationDeclarationPtr();
288   if (AbbrevDecl)
289     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
290   return None;
291 }
292 
293 Optional<DWARFFormValue>
294 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
295   if (!isValid())
296     return None;
297   auto AbbrevDecl = getAbbreviationDeclarationPtr();
298   if (AbbrevDecl) {
299     for (auto Attr : Attrs) {
300       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
301         return Value;
302     }
303   }
304   return None;
305 }
306 
307 Optional<DWARFFormValue>
308 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
309   if (!isValid())
310     return None;
311   if (auto Value = find(Attrs))
312     return Value;
313   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_abstract_origin)) {
314     if (auto Value = Die.findRecursively(Attrs))
315       return Value;
316   }
317   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_specification)) {
318     if (auto Value = Die.findRecursively(Attrs))
319       return Value;
320   }
321   return None;
322 }
323 
324 DWARFDie
325 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
326   if (auto SpecRef = toReference(find(Attr))) {
327     if (auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef))
328       return SpecUnit->getDIEForOffset(*SpecRef);
329   }
330   return DWARFDie();
331 }
332 
333 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
334   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
335 }
336 
337 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
338   if (auto FormValue = find(DW_AT_high_pc)) {
339     if (auto Address = FormValue->getAsAddress()) {
340       // High PC is an address.
341       return Address;
342     }
343     if (auto Offset = FormValue->getAsUnsignedConstant()) {
344       // High PC is an offset from LowPC.
345       return LowPC + *Offset;
346     }
347   }
348   return None;
349 }
350 
351 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
352                                uint64_t &SectionIndex) const {
353   auto F = find(DW_AT_low_pc);
354   auto LowPcAddr = toAddress(F);
355   if (!LowPcAddr)
356     return false;
357   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
358     LowPC = *LowPcAddr;
359     HighPC = *HighPcAddr;
360     SectionIndex = F->getSectionIndex();
361     return true;
362   }
363   return false;
364 }
365 
366 DWARFAddressRangesVector DWARFDie::getAddressRanges() const {
367   if (isNULL())
368     return DWARFAddressRangesVector();
369   // Single range specified by low/high PC.
370   uint64_t LowPC, HighPC, Index;
371   if (getLowAndHighPC(LowPC, HighPC, Index))
372     return {{LowPC, HighPC, Index}};
373 
374   // Multiple ranges from .debug_ranges section.
375   auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
376   if (RangesOffset) {
377     DWARFDebugRangeList RangeList;
378     if (U->extractRangeList(*RangesOffset, RangeList))
379       return RangeList.getAbsoluteRanges(U->getBaseAddress());
380   }
381   return DWARFAddressRangesVector();
382 }
383 
384 void DWARFDie::collectChildrenAddressRanges(
385     DWARFAddressRangesVector &Ranges) const {
386   if (isNULL())
387     return;
388   if (isSubprogramDIE()) {
389     const auto &DIERanges = getAddressRanges();
390     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
391   }
392 
393   for (auto Child : children())
394     Child.collectChildrenAddressRanges(Ranges);
395 }
396 
397 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
398   for (const auto &R : getAddressRanges()) {
399     if (R.LowPC <= Address && Address < R.HighPC)
400       return true;
401   }
402   return false;
403 }
404 
405 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
406   if (!isSubroutineDIE())
407     return nullptr;
408   return getName(Kind);
409 }
410 
411 const char *DWARFDie::getName(DINameKind Kind) const {
412   if (!isValid() || Kind == DINameKind::None)
413     return nullptr;
414   // Try to get mangled name only if it was asked for.
415   if (Kind == DINameKind::LinkageName) {
416     if (auto Name = dwarf::toString(
417             findRecursively({DW_AT_MIPS_linkage_name, DW_AT_linkage_name}),
418             nullptr))
419       return Name;
420   }
421   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
422     return Name;
423   return nullptr;
424 }
425 
426 uint64_t DWARFDie::getDeclLine() const {
427   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
428 }
429 
430 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
431                               uint32_t &CallColumn,
432                               uint32_t &CallDiscriminator) const {
433   CallFile = toUnsigned(find(DW_AT_call_file), 0);
434   CallLine = toUnsigned(find(DW_AT_call_line), 0);
435   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
436   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
437 }
438 
439 /// Helper to dump a DIE with all of its parents, but no siblings.
440 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
441                                 DIDumpOptions DumpOpts) {
442   if (!Die)
443     return Indent;
444   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts);
445   Die.dump(OS, Indent, DumpOpts);
446   return Indent + 2;
447 }
448 
449 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
450                     DIDumpOptions DumpOpts) const {
451   if (!isValid())
452     return;
453   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
454   const uint32_t Offset = getOffset();
455   uint32_t offset = Offset;
456   if (DumpOpts.ShowParents) {
457     DumpOpts.ShowParents = false;
458     Indent = dumpParentChain(getParent(), OS, Indent, DumpOpts);
459   }
460 
461   if (debug_info_data.isValidOffset(offset)) {
462     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
463     if (DumpOpts.ShowAddresses)
464       WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
465 
466     if (abbrCode) {
467       auto AbbrevDecl = getAbbreviationDeclarationPtr();
468       if (AbbrevDecl) {
469         auto tagString = TagString(getTag());
470         if (!tagString.empty())
471           WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
472         else
473           WithColor(OS, syntax::Tag).get().indent(Indent)
474               << format("DW_TAG_Unknown_%x", getTag());
475 
476         if (DumpOpts.Verbose)
477           OS << format(" [%u] %c", abbrCode,
478                        AbbrevDecl->hasChildren() ? '*' : ' ');
479         OS << '\n';
480 
481         // Dump all data in the DIE for the attributes.
482         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
483           if (AttrSpec.Form == DW_FORM_implicit_const) {
484             // We are dumping .debug_info section ,
485             // implicit_const attribute values are not really stored here,
486             // but in .debug_abbrev section. So we just skip such attrs.
487             continue;
488           }
489           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
490                         Indent, DumpOpts);
491         }
492 
493         DWARFDie child = getFirstChild();
494         if (DumpOpts.ShowChildren && DumpOpts.RecurseDepth > 0 && child) {
495           DumpOpts.RecurseDepth--;
496           while (child) {
497             child.dump(OS, Indent + 2, DumpOpts);
498             child = child.getSibling();
499           }
500         }
501       } else {
502         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
503            << abbrCode << '\n';
504       }
505     } else {
506       OS.indent(Indent) << "NULL\n";
507     }
508   }
509 }
510 
511 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
512 
513 DWARFDie DWARFDie::getParent() const {
514   if (isValid())
515     return U->getParent(Die);
516   return DWARFDie();
517 }
518 
519 DWARFDie DWARFDie::getSibling() const {
520   if (isValid())
521     return U->getSibling(Die);
522   return DWARFDie();
523 }
524 
525 DWARFDie DWARFDie::getFirstChild() const {
526   if (isValid())
527     return U->getFirstChild(Die);
528   return DWARFDie();
529 }
530 
531 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
532   return make_range(attribute_iterator(*this, false),
533                     attribute_iterator(*this, true));
534 }
535 
536 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
537     : Die(D), AttrValue(0), Index(0) {
538   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
539   assert(AbbrDecl && "Must have abbreviation declaration");
540   if (End) {
541     // This is the end iterator so we set the index to the attribute count.
542     Index = AbbrDecl->getNumAttributes();
543   } else {
544     // This is the begin iterator so we extract the value for this->Index.
545     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
546     updateForIndex(*AbbrDecl, 0);
547   }
548 }
549 
550 void DWARFDie::attribute_iterator::updateForIndex(
551     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
552   Index = I;
553   // AbbrDecl must be valid before calling this function.
554   auto NumAttrs = AbbrDecl.getNumAttributes();
555   if (Index < NumAttrs) {
556     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
557     // Add the previous byte size of any previous attribute value.
558     AttrValue.Offset += AttrValue.ByteSize;
559     AttrValue.Value.setForm(AbbrDecl.getFormByIndex(Index));
560     uint32_t ParseOffset = AttrValue.Offset;
561     auto U = Die.getDwarfUnit();
562     assert(U && "Die must have valid DWARF unit");
563     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
564                                           &ParseOffset, U->getFormParams(), U);
565     (void)b;
566     assert(b && "extractValue cannot fail on fully parsed DWARF");
567     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
568   } else {
569     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
570     AttrValue.clear();
571   }
572 }
573 
574 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
575   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
576     updateForIndex(*AbbrDecl, Index + 1);
577   return *this;
578 }
579