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