1 //===-- DWARFDebugInfoEntry.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 "SyntaxHighlighting.h"
11 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
13 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
14 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
15 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
16 #include "llvm/Support/DataTypes.h"
17 #include "llvm/Support/Debug.h"
18 #include "llvm/Support/Dwarf.h"
19 #include "llvm/Support/Format.h"
20 #include "llvm/Support/raw_ostream.h"
21 using namespace llvm;
22 using namespace dwarf;
23 using namespace syntax;
24 
25 // Small helper to extract a DIE pointed by a reference
26 // attribute. It looks up the Unit containing the DIE and calls
27 // DIE.extractFast with the right unit. Returns new unit on success,
28 // nullptr otherwise.
findUnitAndExtractFast(DWARFDebugInfoEntryMinimal & DIE,const DWARFUnit * Unit,uint32_t * Offset)29 static const DWARFUnit *findUnitAndExtractFast(DWARFDebugInfoEntryMinimal &DIE,
30                                                const DWARFUnit *Unit,
31                                                uint32_t *Offset) {
32   Unit = Unit->getUnitSection().getUnitForOffset(*Offset);
33   return (Unit && DIE.extractFast(Unit, Offset)) ? Unit : nullptr;
34 }
35 
dump(raw_ostream & OS,DWARFUnit * u,unsigned recurseDepth,unsigned indent) const36 void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, DWARFUnit *u,
37                                       unsigned recurseDepth,
38                                       unsigned indent) const {
39   DataExtractor debug_info_data = u->getDebugInfoExtractor();
40   uint32_t offset = Offset;
41 
42   if (debug_info_data.isValidOffset(offset)) {
43     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
44     WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
45 
46     if (abbrCode) {
47       if (AbbrevDecl) {
48           const char *tagString = TagString(getTag());
49           if (tagString)
50             WithColor(OS, syntax::Tag).get().indent(indent) << tagString;
51           else
52             WithColor(OS, syntax::Tag).get().indent(indent) <<
53               format("DW_TAG_Unknown_%x", getTag());
54 
55         OS << format(" [%u] %c\n", abbrCode,
56                      AbbrevDecl->hasChildren() ? '*' : ' ');
57 
58         // Dump all data in the DIE for the attributes.
59         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
60           dumpAttribute(OS, u, &offset, AttrSpec.Attr, AttrSpec.Form, indent);
61         }
62 
63         const DWARFDebugInfoEntryMinimal *child = getFirstChild();
64         if (recurseDepth > 0 && child) {
65           while (child) {
66             child->dump(OS, u, recurseDepth-1, indent+2);
67             child = child->getSibling();
68           }
69         }
70       } else {
71         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
72            << abbrCode << '\n';
73       }
74     } else {
75       OS.indent(indent) << "NULL\n";
76     }
77   }
78 }
79 
dumpApplePropertyAttribute(raw_ostream & OS,uint64_t Val)80 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
81   OS << " (";
82   do {
83     uint64_t Shift = countTrailingZeros(Val);
84     assert(Shift < 64 && "undefined behavior");
85     uint64_t Bit = 1ULL << Shift;
86     if (const char *PropName = ApplePropertyString(Bit))
87       OS << PropName;
88     else
89       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
90     if (!(Val ^= Bit))
91       break;
92     OS << ", ";
93   } while (true);
94   OS << ")";
95 }
96 
dumpRanges(raw_ostream & OS,const DWARFAddressRangesVector & Ranges,unsigned AddressSize,unsigned Indent)97 static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
98                        unsigned AddressSize, unsigned Indent) {
99   if (Ranges.empty())
100     return;
101 
102   for (const auto &Range: Ranges) {
103     OS << '\n';
104     OS.indent(Indent);
105     OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
106                  AddressSize*2, Range.first,
107                  AddressSize*2, Range.second);
108   }
109 }
110 
dumpAttribute(raw_ostream & OS,DWARFUnit * u,uint32_t * offset_ptr,uint16_t attr,uint16_t form,unsigned indent) const111 void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
112                                                DWARFUnit *u,
113                                                uint32_t *offset_ptr,
114                                                uint16_t attr, uint16_t form,
115                                                unsigned indent) const {
116   const char BaseIndent[] = "            ";
117   OS << BaseIndent;
118   OS.indent(indent+2);
119   const char *attrString = AttributeString(attr);
120   if (attrString)
121     WithColor(OS, syntax::Attribute) << attrString;
122   else
123     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", attr);
124 
125   const char *formString = FormEncodingString(form);
126   if (formString)
127     OS << " [" << formString << ']';
128   else
129     OS << format(" [DW_FORM_Unknown_%x]", form);
130 
131   DWARFFormValue formValue(form);
132 
133   if (!formValue.extractValue(u->getDebugInfoExtractor(), offset_ptr, u))
134     return;
135 
136   OS << "\t(";
137 
138   const char *Name = nullptr;
139   std::string File;
140   auto Color = syntax::Enumerator;
141   if (attr == DW_AT_decl_file || attr == DW_AT_call_file) {
142     Color = syntax::String;
143     if (const auto *LT = u->getContext().getLineTableForUnit(u))
144       if (LT->getFileNameByIndex(
145              formValue.getAsUnsignedConstant().getValue(),
146              u->getCompilationDir(),
147              DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
148         File = '"' + File + '"';
149         Name = File.c_str();
150       }
151   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
152     Name = AttributeValueString(attr, *Val);
153 
154   if (Name)
155     WithColor(OS, Color) << Name;
156   else if (attr == DW_AT_decl_line || attr == DW_AT_call_line)
157     OS << *formValue.getAsUnsignedConstant();
158   else
159     formValue.dump(OS, u);
160 
161   // We have dumped the attribute raw value. For some attributes
162   // having both the raw value and the pretty-printed value is
163   // interesting. These attributes are handled below.
164   if (attr == DW_AT_specification || attr == DW_AT_abstract_origin) {
165     Optional<uint64_t> Ref = formValue.getAsReference(u);
166     if (Ref.hasValue()) {
167       uint32_t RefOffset = Ref.getValue();
168       DWARFDebugInfoEntryMinimal DIE;
169       if (const DWARFUnit *RefU = findUnitAndExtractFast(DIE, u, &RefOffset))
170         if (const char *Name = DIE.getName(RefU, DINameKind::LinkageName))
171           OS << " \"" << Name << '\"';
172     }
173   } else if (attr == DW_AT_APPLE_property_attribute) {
174     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
175       dumpApplePropertyAttribute(OS, *OptVal);
176   } else if (attr == DW_AT_ranges) {
177     dumpRanges(OS, getAddressRanges(u), u->getAddressByteSize(),
178                sizeof(BaseIndent)+indent+4);
179   }
180 
181   OS << ")\n";
182 }
183 
extractFast(const DWARFUnit * U,uint32_t * OffsetPtr)184 bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit *U,
185                                              uint32_t *OffsetPtr) {
186   Offset = *OffsetPtr;
187   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
188   uint32_t UEndOffset = U->getNextUnitOffset();
189   if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
190     return false;
191   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
192   if (0 == AbbrCode) {
193     // NULL debug tag entry.
194     AbbrevDecl = nullptr;
195     return true;
196   }
197   AbbrevDecl = U->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
198   if (nullptr == AbbrevDecl) {
199     // Restore the original offset.
200     *OffsetPtr = Offset;
201     return false;
202   }
203   ArrayRef<uint8_t> FixedFormSizes = DWARFFormValue::getFixedFormSizes(
204       U->getAddressByteSize(), U->getVersion());
205   assert(FixedFormSizes.size() > 0);
206 
207   // Skip all data in the .debug_info for the attributes
208   for (const auto &AttrSpec : AbbrevDecl->attributes()) {
209     uint16_t Form = AttrSpec.Form;
210 
211     uint8_t FixedFormSize =
212         (Form < FixedFormSizes.size()) ? FixedFormSizes[Form] : 0;
213     if (FixedFormSize)
214       *OffsetPtr += FixedFormSize;
215     else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, U)) {
216       // Restore the original offset.
217       *OffsetPtr = Offset;
218       return false;
219     }
220   }
221   return true;
222 }
223 
isSubprogramDIE() const224 bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
225   return getTag() == DW_TAG_subprogram;
226 }
227 
isSubroutineDIE() const228 bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
229   uint32_t Tag = getTag();
230   return Tag == DW_TAG_subprogram ||
231          Tag == DW_TAG_inlined_subroutine;
232 }
233 
getAttributeValue(const DWARFUnit * U,const uint16_t Attr,DWARFFormValue & FormValue) const234 bool DWARFDebugInfoEntryMinimal::getAttributeValue(
235     const DWARFUnit *U, const uint16_t Attr, DWARFFormValue &FormValue) const {
236   if (!AbbrevDecl)
237     return false;
238 
239   uint32_t AttrIdx = AbbrevDecl->findAttributeIndex(Attr);
240   if (AttrIdx == -1U)
241     return false;
242 
243   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
244   uint32_t DebugInfoOffset = getOffset();
245 
246   // Skip the abbreviation code so we are at the data for the attributes
247   DebugInfoData.getULEB128(&DebugInfoOffset);
248 
249   // Skip preceding attribute values.
250   for (uint32_t i = 0; i < AttrIdx; ++i) {
251     DWARFFormValue::skipValue(AbbrevDecl->getFormByIndex(i),
252                               DebugInfoData, &DebugInfoOffset, U);
253   }
254 
255   FormValue = DWARFFormValue(AbbrevDecl->getFormByIndex(AttrIdx));
256   return FormValue.extractValue(DebugInfoData, &DebugInfoOffset, U);
257 }
258 
getAttributeValueAsString(const DWARFUnit * U,const uint16_t Attr,const char * FailValue) const259 const char *DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
260     const DWARFUnit *U, const uint16_t Attr, const char *FailValue) const {
261   DWARFFormValue FormValue;
262   if (!getAttributeValue(U, Attr, FormValue))
263     return FailValue;
264   Optional<const char *> Result = FormValue.getAsCString(U);
265   return Result.hasValue() ? Result.getValue() : FailValue;
266 }
267 
getAttributeValueAsAddress(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const268 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsAddress(
269     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
270   DWARFFormValue FormValue;
271   if (!getAttributeValue(U, Attr, FormValue))
272     return FailValue;
273   Optional<uint64_t> Result = FormValue.getAsAddress(U);
274   return Result.hasValue() ? Result.getValue() : FailValue;
275 }
276 
getAttributeValueAsUnsignedConstant(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const277 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsignedConstant(
278     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
279   DWARFFormValue FormValue;
280   if (!getAttributeValue(U, Attr, FormValue))
281     return FailValue;
282   Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
283   return Result.hasValue() ? Result.getValue() : FailValue;
284 }
285 
getAttributeValueAsReference(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const286 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
287     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
288   DWARFFormValue FormValue;
289   if (!getAttributeValue(U, Attr, FormValue))
290     return FailValue;
291   Optional<uint64_t> Result = FormValue.getAsReference(U);
292   return Result.hasValue() ? Result.getValue() : FailValue;
293 }
294 
getAttributeValueAsSectionOffset(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const295 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
296     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
297   DWARFFormValue FormValue;
298   if (!getAttributeValue(U, Attr, FormValue))
299     return FailValue;
300   Optional<uint64_t> Result = FormValue.getAsSectionOffset();
301   return Result.hasValue() ? Result.getValue() : FailValue;
302 }
303 
304 uint64_t
getRangesBaseAttribute(const DWARFUnit * U,uint64_t FailValue) const305 DWARFDebugInfoEntryMinimal::getRangesBaseAttribute(const DWARFUnit *U,
306                                                    uint64_t FailValue) const {
307   uint64_t Result =
308       getAttributeValueAsSectionOffset(U, DW_AT_ranges_base, -1ULL);
309   if (Result != -1ULL)
310     return Result;
311   return getAttributeValueAsSectionOffset(U, DW_AT_GNU_ranges_base, FailValue);
312 }
313 
getLowAndHighPC(const DWARFUnit * U,uint64_t & LowPC,uint64_t & HighPC) const314 bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
315                                                  uint64_t &LowPC,
316                                                  uint64_t &HighPC) const {
317   LowPC = getAttributeValueAsAddress(U, DW_AT_low_pc, -1ULL);
318   if (LowPC == -1ULL)
319     return false;
320   HighPC = getAttributeValueAsAddress(U, DW_AT_high_pc, -1ULL);
321   if (HighPC == -1ULL) {
322     // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
323     // it represents function size.
324     HighPC = getAttributeValueAsUnsignedConstant(U, DW_AT_high_pc, -1ULL);
325     if (HighPC != -1ULL)
326       HighPC += LowPC;
327   }
328   return (HighPC != -1ULL);
329 }
330 
331 DWARFAddressRangesVector
getAddressRanges(const DWARFUnit * U) const332 DWARFDebugInfoEntryMinimal::getAddressRanges(const DWARFUnit *U) const {
333   if (isNULL())
334     return DWARFAddressRangesVector();
335   // Single range specified by low/high PC.
336   uint64_t LowPC, HighPC;
337   if (getLowAndHighPC(U, LowPC, HighPC)) {
338     return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
339   }
340   // Multiple ranges from .debug_ranges section.
341   uint32_t RangesOffset =
342       getAttributeValueAsSectionOffset(U, DW_AT_ranges, -1U);
343   if (RangesOffset != -1U) {
344     DWARFDebugRangeList RangeList;
345     if (U->extractRangeList(RangesOffset, RangeList))
346       return RangeList.getAbsoluteRanges(U->getBaseAddress());
347   }
348   return DWARFAddressRangesVector();
349 }
350 
collectChildrenAddressRanges(const DWARFUnit * U,DWARFAddressRangesVector & Ranges) const351 void DWARFDebugInfoEntryMinimal::collectChildrenAddressRanges(
352     const DWARFUnit *U, DWARFAddressRangesVector& Ranges) const {
353   if (isNULL())
354     return;
355   if (isSubprogramDIE()) {
356     const auto &DIERanges = getAddressRanges(U);
357     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
358   }
359 
360   const DWARFDebugInfoEntryMinimal *Child = getFirstChild();
361   while (Child) {
362     Child->collectChildrenAddressRanges(U, Ranges);
363     Child = Child->getSibling();
364   }
365 }
366 
addressRangeContainsAddress(const DWARFUnit * U,const uint64_t Address) const367 bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
368     const DWARFUnit *U, const uint64_t Address) const {
369   for (const auto& R : getAddressRanges(U)) {
370     if (R.first <= Address && Address < R.second)
371       return true;
372   }
373   return false;
374 }
375 
376 const char *
getSubroutineName(const DWARFUnit * U,DINameKind Kind) const377 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
378                                               DINameKind Kind) const {
379   if (!isSubroutineDIE())
380     return nullptr;
381   return getName(U, Kind);
382 }
383 
384 const char *
getName(const DWARFUnit * U,DINameKind Kind) const385 DWARFDebugInfoEntryMinimal::getName(const DWARFUnit *U,
386                                     DINameKind Kind) const {
387   if (Kind == DINameKind::None)
388     return nullptr;
389   // Try to get mangled name only if it was asked for.
390   if (Kind == DINameKind::LinkageName) {
391     if (const char *name =
392             getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
393       return name;
394     if (const char *name =
395             getAttributeValueAsString(U, DW_AT_linkage_name, nullptr))
396       return name;
397   }
398   if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
399     return name;
400   // Try to get name from specification DIE.
401   uint32_t spec_ref =
402       getAttributeValueAsReference(U, DW_AT_specification, -1U);
403   if (spec_ref != -1U) {
404     DWARFDebugInfoEntryMinimal spec_die;
405     if (const DWARFUnit *RefU = findUnitAndExtractFast(spec_die, U, &spec_ref)) {
406       if (const char *name = spec_die.getName(RefU, Kind))
407         return name;
408     }
409   }
410   // Try to get name from abstract origin DIE.
411   uint32_t abs_origin_ref =
412       getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
413   if (abs_origin_ref != -1U) {
414     DWARFDebugInfoEntryMinimal abs_origin_die;
415     if (const DWARFUnit *RefU = findUnitAndExtractFast(abs_origin_die, U,
416                                                        &abs_origin_ref)) {
417       if (const char *name = abs_origin_die.getName(RefU, Kind))
418         return name;
419     }
420   }
421   return nullptr;
422 }
423 
getCallerFrame(const DWARFUnit * U,uint32_t & CallFile,uint32_t & CallLine,uint32_t & CallColumn) const424 void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
425                                                 uint32_t &CallFile,
426                                                 uint32_t &CallLine,
427                                                 uint32_t &CallColumn) const {
428   CallFile = getAttributeValueAsUnsignedConstant(U, DW_AT_call_file, 0);
429   CallLine = getAttributeValueAsUnsignedConstant(U, DW_AT_call_line, 0);
430   CallColumn = getAttributeValueAsUnsignedConstant(U, DW_AT_call_column, 0);
431 }
432 
433 DWARFDebugInfoEntryInlinedChain
getInlinedChainForAddress(const DWARFUnit * U,const uint64_t Address) const434 DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
435     const DWARFUnit *U, const uint64_t Address) const {
436   DWARFDebugInfoEntryInlinedChain InlinedChain;
437   InlinedChain.U = U;
438   if (isNULL())
439     return InlinedChain;
440   for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
441     // Append current DIE to inlined chain only if it has correct tag
442     // (e.g. it is not a lexical block).
443     if (DIE->isSubroutineDIE()) {
444       InlinedChain.DIEs.push_back(*DIE);
445     }
446     // Try to get child which also contains provided address.
447     const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
448     while (Child) {
449       if (Child->addressRangeContainsAddress(U, Address)) {
450         // Assume there is only one such child.
451         break;
452       }
453       Child = Child->getSibling();
454     }
455     DIE = Child;
456   }
457   // Reverse the obtained chain to make the root of inlined chain last.
458   std::reverse(InlinedChain.DIEs.begin(), InlinedChain.DIEs.end());
459   return InlinedChain;
460 }
461