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 "llvm/ADT/None.h"
12 #include "llvm/ADT/Optional.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/BinaryFormat/Dwarf.h"
15 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
16 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
17 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
18 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
19 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
20 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
21 #include "llvm/Object/ObjectFile.h"
22 #include "llvm/Support/DataExtractor.h"
23 #include "llvm/Support/Format.h"
24 #include "llvm/Support/FormatVariadic.h"
25 #include "llvm/Support/MathExtras.h"
26 #include "llvm/Support/WithColor.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include <algorithm>
29 #include <cassert>
30 #include <cinttypes>
31 #include <cstdint>
32 #include <string>
33 #include <utility>
34 
35 using namespace llvm;
36 using namespace dwarf;
37 using namespace object;
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 (const DWARFAddressRange &R : Ranges) {
66 
67     OS << '\n';
68     OS.indent(Indent);
69     R.dump(OS, AddressSize);
70 
71     if (SectionNames.empty() || R.SectionIndex == -1ULL)
72       continue;
73 
74     StringRef Name = SectionNames[R.SectionIndex].Name;
75     OS << " \"" << Name << '\"';
76 
77     // Print section index if name is not unique.
78     if (!SectionNames[R.SectionIndex].IsNameUnique)
79       OS << format(" [%" PRIu64 "]", R.SectionIndex);
80   }
81 }
82 
83 static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
84                          DWARFUnit *U, unsigned Indent,
85                          DIDumpOptions DumpOpts) {
86   DWARFContext &Ctx = U->getContext();
87   const DWARFObject &Obj = Ctx.getDWARFObj();
88   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
89   if (FormValue.isFormClass(DWARFFormValue::FC_Block) ||
90       FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) {
91     ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
92     DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
93                        Ctx.isLittleEndian(), 0);
94     DWARFExpression(Data, U->getVersion(), U->getAddressByteSize())
95         .print(OS, MRI);
96     return;
97   }
98 
99   FormValue.dump(OS, DumpOpts);
100   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
101     const DWARFSection &LocSection = Obj.getLocSection();
102     const DWARFSection &LocDWOSection = Obj.getLocDWOSection();
103     uint32_t Offset = *FormValue.getAsSectionOffset();
104 
105     if (!LocSection.Data.empty()) {
106       DWARFDebugLoc DebugLoc;
107       DWARFDataExtractor Data(Obj, LocSection, Ctx.isLittleEndian(),
108                               Obj.getAddressSize());
109       auto LL = DebugLoc.parseOneLocationList(Data, &Offset);
110       if (LL)
111         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
112       else
113         OS << "error extracting location list.";
114     } else if (!LocDWOSection.Data.empty()) {
115       DataExtractor Data(LocDWOSection.Data, Ctx.isLittleEndian(), 0);
116       auto LL = DWARFDebugLocDWO::parseOneLocationList(Data, &Offset);
117       if (LL)
118         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
119       else
120         OS << "error extracting location list.";
121     }
122   }
123 }
124 
125 /// Dump the name encoded in the type tag.
126 static void dumpTypeTagName(raw_ostream &OS, dwarf::Tag T) {
127   StringRef TagStr = TagString(T);
128   if (!TagStr.startswith("DW_TAG_") || !TagStr.endswith("_type"))
129     return;
130   OS << TagStr.substr(7, TagStr.size() - 12) << " ";
131 }
132 
133 /// Recursively dump the DIE type name when applicable.
134 static void dumpTypeName(raw_ostream &OS, const DWARFDie &Die) {
135   DWARFDie D = Die.getAttributeValueAsReferencedDie(DW_AT_type);
136 
137   if (!D.isValid())
138     return;
139 
140   if (const char *Name = D.getName(DINameKind::LinkageName)) {
141     OS << Name;
142     return;
143   }
144 
145   // FIXME: We should have pretty printers per language. Currently we print
146   // everything as if it was C++ and fall back to the TAG type name.
147   const dwarf::Tag T = D.getTag();
148   switch (T) {
149   case DW_TAG_array_type:
150   case DW_TAG_pointer_type:
151   case DW_TAG_ptr_to_member_type:
152   case DW_TAG_reference_type:
153   case DW_TAG_rvalue_reference_type:
154     break;
155   default:
156     dumpTypeTagName(OS, T);
157   }
158 
159   // Follow the DW_AT_type if possible.
160   dumpTypeName(OS, D);
161 
162   switch (T) {
163   case DW_TAG_array_type:
164     OS << "[]";
165     break;
166   case DW_TAG_pointer_type:
167     OS << '*';
168     break;
169   case DW_TAG_ptr_to_member_type:
170     OS << '*';
171     break;
172   case DW_TAG_reference_type:
173     OS << '&';
174     break;
175   case DW_TAG_rvalue_reference_type:
176     OS << "&&";
177     break;
178   default:
179     break;
180   }
181 }
182 
183 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
184                           uint32_t *OffsetPtr, dwarf::Attribute Attr,
185                           dwarf::Form Form, unsigned Indent,
186                           DIDumpOptions DumpOpts) {
187   if (!Die.isValid())
188     return;
189   const char BaseIndent[] = "            ";
190   OS << BaseIndent;
191   OS.indent(Indent + 2);
192   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
193 
194   if (DumpOpts.Verbose || DumpOpts.ShowForm)
195     OS << formatv(" [{0}]", Form);
196 
197   DWARFUnit *U = Die.getDwarfUnit();
198   DWARFFormValue formValue(Form);
199 
200   if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr,
201                               U->getFormParams(), U))
202     return;
203 
204   OS << "\t(";
205 
206   StringRef Name;
207   std::string File;
208   auto Color = HighlightColor::Enumerator;
209   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
210     Color = HighlightColor::String;
211     if (const auto *LT = U->getContext().getLineTableForUnit(U))
212       if (LT->getFileNameByIndex(
213               formValue.getAsUnsignedConstant().getValue(),
214               U->getCompilationDir(),
215               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
216         File = '"' + File + '"';
217         Name = File;
218       }
219   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
220     Name = AttributeValueString(Attr, *Val);
221 
222   if (!Name.empty())
223     WithColor(OS, Color) << Name;
224   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
225     OS << *formValue.getAsUnsignedConstant();
226   else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
227            formValue.getAsUnsignedConstant()) {
228     if (DumpOpts.ShowAddresses) {
229       // Print the actual address rather than the offset.
230       uint64_t LowPC, HighPC, Index;
231       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
232         OS << format("0x%016" PRIx64, HighPC);
233       else
234         formValue.dump(OS, DumpOpts);
235     }
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   if (auto Value = find(Attrs))
301     return Value;
302   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_abstract_origin)) {
303     if (auto Value = Die.findRecursively(Attrs))
304       return Value;
305   }
306   if (auto Die = getAttributeValueAsReferencedDie(DW_AT_specification)) {
307     if (auto Value = Die.findRecursively(Attrs))
308       return Value;
309   }
310   return None;
311 }
312 
313 DWARFDie
314 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
315   if (auto SpecRef = toReference(find(Attr))) {
316     if (auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef))
317       return SpecUnit->getDIEForOffset(*SpecRef);
318   }
319   return DWARFDie();
320 }
321 
322 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
323   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
324 }
325 
326 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
327   if (auto FormValue = find(DW_AT_high_pc)) {
328     if (auto Address = FormValue->getAsAddress()) {
329       // High PC is an address.
330       return Address;
331     }
332     if (auto Offset = FormValue->getAsUnsignedConstant()) {
333       // High PC is an offset from LowPC.
334       return LowPC + *Offset;
335     }
336   }
337   return None;
338 }
339 
340 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
341                                uint64_t &SectionIndex) const {
342   auto F = find(DW_AT_low_pc);
343   auto LowPcAddr = toAddress(F);
344   if (!LowPcAddr)
345     return false;
346   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
347     LowPC = *LowPcAddr;
348     HighPC = *HighPcAddr;
349     SectionIndex = F->getSectionIndex();
350     return true;
351   }
352   return false;
353 }
354 
355 DWARFAddressRangesVector DWARFDie::getAddressRanges() const {
356   if (isNULL())
357     return DWARFAddressRangesVector();
358   // Single range specified by low/high PC.
359   uint64_t LowPC, HighPC, Index;
360   if (getLowAndHighPC(LowPC, HighPC, Index))
361     return {{LowPC, HighPC, Index}};
362 
363   // Multiple ranges from .debug_ranges section.
364   auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
365   if (RangesOffset) {
366     DWARFDebugRangeList RangeList;
367     if (U->extractRangeList(*RangesOffset, RangeList))
368       return RangeList.getAbsoluteRanges(U->getBaseAddress());
369   }
370   return DWARFAddressRangesVector();
371 }
372 
373 void DWARFDie::collectChildrenAddressRanges(
374     DWARFAddressRangesVector &Ranges) const {
375   if (isNULL())
376     return;
377   if (isSubprogramDIE()) {
378     const auto &DIERanges = getAddressRanges();
379     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
380   }
381 
382   for (auto Child : children())
383     Child.collectChildrenAddressRanges(Ranges);
384 }
385 
386 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
387   for (const auto &R : getAddressRanges()) {
388     if (R.LowPC <= Address && Address < R.HighPC)
389       return true;
390   }
391   return false;
392 }
393 
394 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
395   if (!isSubroutineDIE())
396     return nullptr;
397   return getName(Kind);
398 }
399 
400 const char *DWARFDie::getName(DINameKind Kind) const {
401   if (!isValid() || Kind == DINameKind::None)
402     return nullptr;
403   // Try to get mangled name only if it was asked for.
404   if (Kind == DINameKind::LinkageName) {
405     if (auto Name = dwarf::toString(
406             findRecursively({DW_AT_MIPS_linkage_name, DW_AT_linkage_name}),
407             nullptr))
408       return Name;
409   }
410   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
411     return Name;
412   return nullptr;
413 }
414 
415 uint64_t DWARFDie::getDeclLine() const {
416   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
417 }
418 
419 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
420                               uint32_t &CallColumn,
421                               uint32_t &CallDiscriminator) const {
422   CallFile = toUnsigned(find(DW_AT_call_file), 0);
423   CallLine = toUnsigned(find(DW_AT_call_line), 0);
424   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
425   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
426 }
427 
428 /// Helper to dump a DIE with all of its parents, but no siblings.
429 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
430                                 DIDumpOptions DumpOpts) {
431   if (!Die)
432     return Indent;
433   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts);
434   Die.dump(OS, Indent, DumpOpts);
435   return Indent + 2;
436 }
437 
438 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
439                     DIDumpOptions DumpOpts) const {
440   if (!isValid())
441     return;
442   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
443   const uint32_t Offset = getOffset();
444   uint32_t offset = Offset;
445   if (DumpOpts.ShowParents) {
446     DumpOpts.ShowParents = false;
447     Indent = dumpParentChain(getParent(), OS, Indent, DumpOpts);
448   }
449 
450   if (debug_info_data.isValidOffset(offset)) {
451     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
452     if (DumpOpts.ShowAddresses)
453       WithColor(OS, HighlightColor::Address).get()
454           << format("\n0x%8.8x: ", Offset);
455 
456     if (abbrCode) {
457       auto AbbrevDecl = getAbbreviationDeclarationPtr();
458       if (AbbrevDecl) {
459         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
460             << formatv("{0}", getTag());
461         if (DumpOpts.Verbose)
462           OS << format(" [%u] %c", abbrCode,
463                        AbbrevDecl->hasChildren() ? '*' : ' ');
464         OS << '\n';
465 
466         // Dump all data in the DIE for the attributes.
467         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
468           if (AttrSpec.Form == DW_FORM_implicit_const) {
469             // We are dumping .debug_info section ,
470             // implicit_const attribute values are not really stored here,
471             // but in .debug_abbrev section. So we just skip such attrs.
472             continue;
473           }
474           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
475                         Indent, DumpOpts);
476         }
477 
478         DWARFDie child = getFirstChild();
479         if (DumpOpts.ShowChildren && DumpOpts.RecurseDepth > 0 && child) {
480           DumpOpts.RecurseDepth--;
481           while (child) {
482             child.dump(OS, Indent + 2, DumpOpts);
483             child = child.getSibling();
484           }
485         }
486       } else {
487         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
488            << abbrCode << '\n';
489       }
490     } else {
491       OS.indent(Indent) << "NULL\n";
492     }
493   }
494 }
495 
496 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
497 
498 DWARFDie DWARFDie::getParent() const {
499   if (isValid())
500     return U->getParent(Die);
501   return DWARFDie();
502 }
503 
504 DWARFDie DWARFDie::getSibling() const {
505   if (isValid())
506     return U->getSibling(Die);
507   return DWARFDie();
508 }
509 
510 DWARFDie DWARFDie::getFirstChild() const {
511   if (isValid())
512     return U->getFirstChild(Die);
513   return DWARFDie();
514 }
515 
516 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
517   return make_range(attribute_iterator(*this, false),
518                     attribute_iterator(*this, true));
519 }
520 
521 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
522     : Die(D), AttrValue(0), Index(0) {
523   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
524   assert(AbbrDecl && "Must have abbreviation declaration");
525   if (End) {
526     // This is the end iterator so we set the index to the attribute count.
527     Index = AbbrDecl->getNumAttributes();
528   } else {
529     // This is the begin iterator so we extract the value for this->Index.
530     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
531     updateForIndex(*AbbrDecl, 0);
532   }
533 }
534 
535 void DWARFDie::attribute_iterator::updateForIndex(
536     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
537   Index = I;
538   // AbbrDecl must be valid before calling this function.
539   auto NumAttrs = AbbrDecl.getNumAttributes();
540   if (Index < NumAttrs) {
541     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
542     // Add the previous byte size of any previous attribute value.
543     AttrValue.Offset += AttrValue.ByteSize;
544     AttrValue.Value.setForm(AbbrDecl.getFormByIndex(Index));
545     uint32_t ParseOffset = AttrValue.Offset;
546     auto U = Die.getDwarfUnit();
547     assert(U && "Die must have valid DWARF unit");
548     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
549                                           &ParseOffset, U->getFormParams(), U);
550     (void)b;
551     assert(b && "extractValue cannot fail on fully parsed DWARF");
552     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
553   } else {
554     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
555     AttrValue.clear();
556   }
557 }
558 
559 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
560   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
561     updateForIndex(*AbbrDecl, Index + 1);
562   return *this;
563 }
564