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/DebugInfo/DWARF/DWARFCompileUnit.h"
13 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
14 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
15 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h"
16 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
17 #include "llvm/Support/DataTypes.h"
18 #include "llvm/Support/Debug.h"
19 #include "llvm/Support/Dwarf.h"
20 #include "llvm/Support/Format.h"
21 #include "llvm/Support/raw_ostream.h"
22 
23 using namespace llvm;
24 using namespace dwarf;
25 using namespace syntax;
26 
27 namespace {
28  static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
29   OS << " (";
30   do {
31     uint64_t Shift = countTrailingZeros(Val);
32     assert(Shift < 64 && "undefined behavior");
33     uint64_t Bit = 1ULL << Shift;
34     auto PropName = ApplePropertyString(Bit);
35     if (!PropName.empty())
36       OS << PropName;
37     else
38       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
39     if (!(Val ^= Bit))
40       break;
41     OS << ", ";
42   } while (true);
43   OS << ")";
44 }
45 
46 static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
47                        unsigned AddressSize, unsigned Indent) {
48   if (Ranges.empty())
49     return;
50 
51   for (const auto &Range: Ranges) {
52     OS << '\n';
53     OS.indent(Indent);
54     OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
55                  AddressSize*2, Range.first,
56                  AddressSize*2, Range.second);
57   }
58 }
59 
60 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
61                           uint32_t *OffsetPtr, dwarf::Attribute Attr,
62                           dwarf::Form Form, unsigned Indent) {
63   if (!Die.isValid())
64     return;
65   const char BaseIndent[] = "            ";
66   OS << BaseIndent;
67   OS.indent(Indent+2);
68   auto attrString = AttributeString(Attr);
69   if (!attrString.empty())
70     WithColor(OS, syntax::Attribute) << attrString;
71   else
72     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", Attr);
73 
74   auto formString = FormEncodingString(Form);
75   if (!formString.empty())
76     OS << " [" << formString << ']';
77   else
78     OS << format(" [DW_FORM_Unknown_%x]", Form);
79 
80   DWARFUnit *U = Die.getDwarfUnit();
81   DWARFFormValue formValue(Form);
82 
83   if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr, U))
84     return;
85 
86   OS << "\t(";
87 
88   StringRef Name;
89   std::string File;
90   auto Color = syntax::Enumerator;
91   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
92     Color = syntax::String;
93     if (const auto *LT = U->getContext().getLineTableForUnit(U))
94       if (LT->getFileNameByIndex(formValue.getAsUnsignedConstant().getValue(), U->getCompilationDir(), DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
95         File = '"' + File + '"';
96         Name = File;
97       }
98   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
99     Name = AttributeValueString(Attr, *Val);
100 
101   if (!Name.empty())
102     WithColor(OS, Color) << Name;
103   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
104     OS << *formValue.getAsUnsignedConstant();
105   else
106     formValue.dump(OS);
107 
108   // We have dumped the attribute raw value. For some attributes
109   // having both the raw value and the pretty-printed value is
110   // interesting. These attributes are handled below.
111   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
112     if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(DINameKind::LinkageName))
113         OS << " \"" << Name << '\"';
114   } else if (Attr == DW_AT_APPLE_property_attribute) {
115     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
116       dumpApplePropertyAttribute(OS, *OptVal);
117   } else if (Attr == DW_AT_ranges) {
118     dumpRanges(OS, Die.getAddressRanges(), U->getAddressByteSize(),
119                sizeof(BaseIndent)+Indent+4);
120   }
121 
122   OS << ")\n";
123 }
124 
125 } // end anonymous namespace
126 
127 bool DWARFDie::isSubprogramDIE() const {
128   return getTag() == DW_TAG_subprogram;
129 }
130 
131 bool DWARFDie::isSubroutineDIE() const {
132   auto Tag = getTag();
133   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
134 }
135 
136 Optional<DWARFFormValue>
137 DWARFDie::getAttributeValue(dwarf::Attribute Attr) const {
138   if (!isValid())
139     return None;
140   auto AbbrevDecl = getAbbreviationDeclarationPtr();
141   if (AbbrevDecl)
142     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
143   return None;
144 }
145 
146 const char *DWARFDie::getAttributeValueAsString(dwarf::Attribute Attr,
147                                                 const char *FailValue) const {
148   auto FormValue = getAttributeValue(Attr);
149   if (!FormValue)
150     return FailValue;
151   Optional<const char *> Result = FormValue->getAsCString();
152   return Result.hasValue() ? Result.getValue() : FailValue;
153 }
154 
155 Optional<uint64_t>
156 DWARFDie::getAttributeValueAsAddress(dwarf::Attribute Attr) const {
157   if (auto FormValue = getAttributeValue(Attr))
158     return FormValue->getAsAddress();
159   return None;
160 }
161 
162 Optional<int64_t>
163 DWARFDie::getAttributeValueAsSignedConstant(dwarf::Attribute Attr) const {
164   if (auto FormValue = getAttributeValue(Attr))
165     return FormValue->getAsSignedConstant();
166   return None;
167 }
168 
169 Optional<uint64_t>
170 DWARFDie::getAttributeValueAsUnsignedConstant(dwarf::Attribute Attr) const {
171   if (auto FormValue = getAttributeValue(Attr))
172     return FormValue->getAsUnsignedConstant();
173   return None;
174 }
175 
176 Optional<uint64_t>
177 DWARFDie::getAttributeValueAsReference(dwarf::Attribute Attr) const {
178   if (auto FormValue = getAttributeValue(Attr))
179     return FormValue->getAsReference();
180   return None;
181 }
182 
183 Optional<uint64_t>
184 DWARFDie::getAttributeValueAsSectionOffset(dwarf::Attribute Attr) const {
185   if (auto FormValue = getAttributeValue(Attr))
186     return FormValue->getAsSectionOffset();
187   return None;
188 }
189 
190 
191 DWARFDie
192 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
193   auto SpecRef = getAttributeValueAsReference(Attr);
194   if (SpecRef) {
195     auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef);
196     if (SpecUnit)
197       return SpecUnit->getDIEForOffset(*SpecRef);
198   }
199   return DWARFDie();
200 }
201 
202 Optional<uint64_t>
203 DWARFDie::getRangesBaseAttribute() const {
204   auto Result = getAttributeValueAsSectionOffset(DW_AT_rnglists_base);
205   if (Result)
206     return Result;
207   return getAttributeValueAsSectionOffset(DW_AT_GNU_ranges_base);
208 }
209 
210 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
211   if (auto FormValue = getAttributeValue(DW_AT_high_pc)) {
212     if (auto Address = FormValue->getAsAddress()) {
213       // High PC is an address.
214       return Address;
215     }
216     if (auto Offset = FormValue->getAsUnsignedConstant()) {
217       // High PC is an offset from LowPC.
218       return LowPC + *Offset;
219     }
220   }
221   return None;
222 }
223 
224 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC) const {
225   auto LowPcAddr = getAttributeValueAsAddress(DW_AT_low_pc);
226   if (!LowPcAddr)
227     return false;
228   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
229     LowPC = *LowPcAddr;
230     HighPC = *HighPcAddr;
231     return true;
232   }
233   return false;
234 }
235 
236 DWARFAddressRangesVector
237 DWARFDie::getAddressRanges() const {
238   if (isNULL())
239     return DWARFAddressRangesVector();
240   // Single range specified by low/high PC.
241   uint64_t LowPC, HighPC;
242   if (getLowAndHighPC(LowPC, HighPC)) {
243     return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
244   }
245   // Multiple ranges from .debug_ranges section.
246   auto RangesOffset = getAttributeValueAsSectionOffset(DW_AT_ranges);
247   if (RangesOffset) {
248     DWARFDebugRangeList RangeList;
249     if (U->extractRangeList(*RangesOffset, RangeList))
250       return RangeList.getAbsoluteRanges(U->getBaseAddress());
251   }
252   return DWARFAddressRangesVector();
253 }
254 
255 void
256 DWARFDie::collectChildrenAddressRanges(DWARFAddressRangesVector& Ranges) const {
257   if (isNULL())
258     return;
259   if (isSubprogramDIE()) {
260     const auto &DIERanges = getAddressRanges();
261     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
262   }
263 
264   for (auto Child: children())
265     Child.collectChildrenAddressRanges(Ranges);
266 }
267 
268 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
269   for (const auto& R : getAddressRanges()) {
270     if (R.first <= Address && Address < R.second)
271       return true;
272   }
273   return false;
274 }
275 
276 const char *
277 DWARFDie::getSubroutineName(DINameKind Kind) const {
278   if (!isSubroutineDIE())
279     return nullptr;
280   return getName(Kind);
281 }
282 
283 const char *
284 DWARFDie::getName(DINameKind Kind) const {
285   if (!isValid() || Kind == DINameKind::None)
286     return nullptr;
287   const char *name = nullptr;
288   // Try to get mangled name only if it was asked for.
289   if (Kind == DINameKind::LinkageName) {
290     if ((name = getAttributeValueAsString(DW_AT_MIPS_linkage_name, nullptr)))
291       return name;
292     if ((name = getAttributeValueAsString(DW_AT_linkage_name, nullptr)))
293       return name;
294   }
295   if ((name = getAttributeValueAsString(DW_AT_name, nullptr)))
296     return name;
297   // Try to get name from specification DIE.
298   DWARFDie SpecDie = getAttributeValueAsReferencedDie(DW_AT_specification);
299   if (SpecDie && (name = SpecDie.getName(Kind)))
300     return name;
301   // Try to get name from abstract origin DIE.
302   DWARFDie AbsDie = getAttributeValueAsReferencedDie(DW_AT_abstract_origin);
303   if (AbsDie && (name = AbsDie.getName(Kind)))
304     return name;
305   return nullptr;
306 }
307 
308 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
309                               uint32_t &CallColumn) const {
310   CallFile = getAttributeValueAsUnsignedConstant(DW_AT_call_file).getValueOr(0);
311   CallLine = getAttributeValueAsUnsignedConstant(DW_AT_call_line).getValueOr(0);
312   CallColumn =
313       getAttributeValueAsUnsignedConstant(DW_AT_call_column).getValueOr(0);
314 }
315 
316 void DWARFDie::dump(raw_ostream &OS, unsigned RecurseDepth,
317                     unsigned Indent) const {
318   if (!isValid())
319     return;
320   DataExtractor debug_info_data = U->getDebugInfoExtractor();
321   const uint32_t Offset = getOffset();
322   uint32_t offset = Offset;
323 
324   if (debug_info_data.isValidOffset(offset)) {
325     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
326     WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
327 
328     if (abbrCode) {
329       auto AbbrevDecl = getAbbreviationDeclarationPtr();
330       if (AbbrevDecl) {
331         auto tagString = TagString(getTag());
332         if (!tagString.empty())
333           WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
334         else
335           WithColor(OS, syntax::Tag).get().indent(Indent)
336           << format("DW_TAG_Unknown_%x", getTag());
337 
338         OS << format(" [%u] %c\n", abbrCode,
339                      AbbrevDecl->hasChildren() ? '*' : ' ');
340 
341         // Dump all data in the DIE for the attributes.
342         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
343           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
344                         Indent);
345         }
346 
347         DWARFDie child = getFirstChild();
348         if (RecurseDepth > 0 && child) {
349           while (child) {
350             child.dump(OS, RecurseDepth-1, Indent+2);
351             child = child.getSibling();
352           }
353         }
354       } else {
355         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
356         << abbrCode << '\n';
357       }
358     } else {
359       OS.indent(Indent) << "NULL\n";
360     }
361   }
362 }
363 
364 
365 void DWARFDie::getInlinedChainForAddress(
366     const uint64_t Address, SmallVectorImpl<DWARFDie> &InlinedChain) const {
367   if (isNULL())
368     return;
369   DWARFDie DIE(*this);
370   while (DIE) {
371     // Append current DIE to inlined chain only if it has correct tag
372     // (e.g. it is not a lexical block).
373     if (DIE.isSubroutineDIE())
374       InlinedChain.push_back(DIE);
375 
376     // Try to get child which also contains provided address.
377     DWARFDie Child = DIE.getFirstChild();
378     while (Child) {
379       if (Child.addressRangeContainsAddress(Address)) {
380         // Assume there is only one such child.
381         break;
382       }
383       Child = Child.getSibling();
384     }
385     DIE = Child;
386   }
387   // Reverse the obtained chain to make the root of inlined chain last.
388   std::reverse(InlinedChain.begin(), InlinedChain.end());
389 }
390 
391 DWARFDie DWARFDie::getParent() const {
392   if (isValid())
393     return U->getParent(Die);
394   return DWARFDie();
395 }
396 
397 DWARFDie DWARFDie::getSibling() const {
398   if (isValid())
399     return U->getSibling(Die);
400   return DWARFDie();
401 }
402