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/DWARFFormValue.h"
20 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
21 #include "llvm/Support/DataExtractor.h"
22 #include "llvm/Support/Format.h"
23 #include "llvm/Support/MathExtras.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <algorithm>
26 #include <cassert>
27 #include <cinttypes>
28 #include <cstdint>
29 #include <string>
30 #include <utility>
31 
32 using namespace llvm;
33 using namespace dwarf;
34 using namespace syntax;
35 
36 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
37   OS << " (";
38   do {
39     uint64_t Shift = countTrailingZeros(Val);
40     assert(Shift < 64 && "undefined behavior");
41     uint64_t Bit = 1ULL << Shift;
42     auto PropName = ApplePropertyString(Bit);
43     if (!PropName.empty())
44       OS << PropName;
45     else
46       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
47     if (!(Val ^= Bit))
48       break;
49     OS << ", ";
50   } while (true);
51   OS << ")";
52 }
53 
54 static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
55                        unsigned AddressSize, unsigned Indent) {
56   if (Ranges.empty())
57     return;
58 
59   for (const auto &Range: Ranges) {
60     OS << '\n';
61     OS.indent(Indent);
62     OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
63                  AddressSize*2, Range.LowPC,
64                  AddressSize*2, Range.HighPC);
65   }
66 }
67 
68 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
69                           uint32_t *OffsetPtr, dwarf::Attribute Attr,
70                           dwarf::Form Form, unsigned Indent,
71                           DIDumpOptions DumpOpts) {
72   if (!Die.isValid())
73     return;
74   const char BaseIndent[] = "            ";
75   OS << BaseIndent;
76   OS.indent(Indent+2);
77   auto attrString = AttributeString(Attr);
78   if (!attrString.empty())
79     WithColor(OS, syntax::Attribute) << attrString;
80   else
81     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", Attr);
82 
83   if (!DumpOpts.Brief) {
84     auto formString = FormEncodingString(Form);
85     if (!formString.empty())
86       OS << " [" << formString << ']';
87     else
88       OS << format(" [DW_FORM_Unknown_%x]", Form);
89   }
90 
91   DWARFUnit *U = Die.getDwarfUnit();
92   DWARFFormValue formValue(Form);
93 
94   if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr, U))
95     return;
96 
97   OS << "\t(";
98 
99   StringRef Name;
100   std::string File;
101   auto Color = syntax::Enumerator;
102   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
103     Color = syntax::String;
104     if (const auto *LT = U->getContext().getLineTableForUnit(U))
105       if (LT->getFileNameByIndex(formValue.getAsUnsignedConstant().getValue(), U->getCompilationDir(), DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
106         File = '"' + File + '"';
107         Name = File;
108       }
109   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
110     Name = AttributeValueString(Attr, *Val);
111 
112   if (!Name.empty())
113     WithColor(OS, Color) << Name;
114   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
115     OS << *formValue.getAsUnsignedConstant();
116   else
117     formValue.dump(OS);
118 
119   // We have dumped the attribute raw value. For some attributes
120   // having both the raw value and the pretty-printed value is
121   // interesting. These attributes are handled below.
122   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
123     if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(DINameKind::LinkageName))
124         OS << " \"" << Name << '\"';
125   } else if (Attr == DW_AT_APPLE_property_attribute) {
126     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
127       dumpApplePropertyAttribute(OS, *OptVal);
128   } else if (Attr == DW_AT_ranges) {
129     dumpRanges(OS, Die.getAddressRanges(), U->getAddressByteSize(),
130                sizeof(BaseIndent)+Indent+4);
131   }
132 
133   OS << ")\n";
134 }
135 
136 bool DWARFDie::isSubprogramDIE() const {
137   return getTag() == DW_TAG_subprogram;
138 }
139 
140 bool DWARFDie::isSubroutineDIE() const {
141   auto Tag = getTag();
142   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
143 }
144 
145 Optional<DWARFFormValue>
146 DWARFDie::find(dwarf::Attribute Attr) const {
147   if (!isValid())
148     return None;
149   auto AbbrevDecl = getAbbreviationDeclarationPtr();
150   if (AbbrevDecl)
151     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
152   return None;
153 }
154 
155 Optional<DWARFFormValue>
156 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
157   if (!isValid())
158     return None;
159   auto AbbrevDecl = getAbbreviationDeclarationPtr();
160   if (AbbrevDecl) {
161     for (auto Attr : Attrs) {
162       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
163         return Value;
164     }
165   }
166   return None;
167 }
168 
169 Optional<DWARFFormValue>
170 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
171   if (!isValid())
172     return None;
173   auto Die = *this;
174   if (auto Value = Die.find(Attrs))
175     return Value;
176   if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
177     Die = D;
178   if (auto Value = Die.find(Attrs))
179     return Value;
180   if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
181     Die = D;
182   if (auto Value = Die.find(Attrs))
183     return Value;
184   return None;
185 }
186 
187 DWARFDie
188 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
189   auto SpecRef = toReference(find(Attr));
190   if (SpecRef) {
191     auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef);
192     if (SpecUnit)
193       return SpecUnit->getDIEForOffset(*SpecRef);
194   }
195   return DWARFDie();
196 }
197 
198 Optional<uint64_t>
199 DWARFDie::getRangesBaseAttribute() const {
200   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
201 }
202 
203 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
204   if (auto FormValue = find(DW_AT_high_pc)) {
205     if (auto Address = FormValue->getAsAddress()) {
206       // High PC is an address.
207       return Address;
208     }
209     if (auto Offset = FormValue->getAsUnsignedConstant()) {
210       // High PC is an offset from LowPC.
211       return LowPC + *Offset;
212     }
213   }
214   return None;
215 }
216 
217 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
218                                uint64_t &SectionIndex) const {
219   auto F = find(DW_AT_low_pc);
220   auto LowPcAddr = toAddress(F);
221   if (!LowPcAddr)
222     return false;
223   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
224     LowPC = *LowPcAddr;
225     HighPC = *HighPcAddr;
226     SectionIndex = F->getSectionIndex();
227     return true;
228   }
229   return false;
230 }
231 
232 DWARFAddressRangesVector
233 DWARFDie::getAddressRanges() const {
234   if (isNULL())
235     return DWARFAddressRangesVector();
236   // Single range specified by low/high PC.
237   uint64_t LowPC, HighPC, Index;
238   if (getLowAndHighPC(LowPC, HighPC, Index))
239     return {{LowPC, HighPC, Index}};
240 
241   // Multiple ranges from .debug_ranges section.
242   auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
243   if (RangesOffset) {
244     DWARFDebugRangeList RangeList;
245     if (U->extractRangeList(*RangesOffset, RangeList))
246       return RangeList.getAbsoluteRanges(U->getBaseAddress());
247   }
248   return DWARFAddressRangesVector();
249 }
250 
251 void
252 DWARFDie::collectChildrenAddressRanges(DWARFAddressRangesVector& Ranges) const {
253   if (isNULL())
254     return;
255   if (isSubprogramDIE()) {
256     const auto &DIERanges = getAddressRanges();
257     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
258   }
259 
260   for (auto Child: children())
261     Child.collectChildrenAddressRanges(Ranges);
262 }
263 
264 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
265   for (const auto& R : getAddressRanges()) {
266     if (R.LowPC <= Address && Address < R.HighPC)
267       return true;
268   }
269   return false;
270 }
271 
272 const char *
273 DWARFDie::getSubroutineName(DINameKind Kind) const {
274   if (!isSubroutineDIE())
275     return nullptr;
276   return getName(Kind);
277 }
278 
279 const char *
280 DWARFDie::getName(DINameKind Kind) const {
281   if (!isValid() || Kind == DINameKind::None)
282     return nullptr;
283   // Try to get mangled name only if it was asked for.
284   if (Kind == DINameKind::LinkageName) {
285     if (auto Name = dwarf::toString(findRecursively({DW_AT_MIPS_linkage_name,
286                                     DW_AT_linkage_name}), nullptr))
287       return Name;
288   }
289   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
290     return Name;
291   return nullptr;
292 }
293 
294 uint64_t DWARFDie::getDeclLine() const {
295   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
296 }
297 
298 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
299                               uint32_t &CallColumn,
300                               uint32_t &CallDiscriminator) const {
301   CallFile = toUnsigned(find(DW_AT_call_file), 0);
302   CallLine = toUnsigned(find(DW_AT_call_line), 0);
303   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
304   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
305 }
306 
307 void DWARFDie::dump(raw_ostream &OS, unsigned RecurseDepth, unsigned Indent,
308                     DIDumpOptions DumpOpts) const {
309   if (!isValid())
310     return;
311   DataExtractor debug_info_data = U->getDebugInfoExtractor();
312   const uint32_t Offset = getOffset();
313   uint32_t offset = Offset;
314 
315   if (debug_info_data.isValidOffset(offset)) {
316     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
317     WithColor(OS, syntax::Address).get() << format("\n0x%8.8x: ", Offset);
318 
319     if (abbrCode) {
320       auto AbbrevDecl = getAbbreviationDeclarationPtr();
321       if (AbbrevDecl) {
322         auto tagString = TagString(getTag());
323         if (!tagString.empty())
324           WithColor(OS, syntax::Tag).get().indent(Indent) << tagString;
325         else
326           WithColor(OS, syntax::Tag).get().indent(Indent)
327           << format("DW_TAG_Unknown_%x", getTag());
328 
329         if (!DumpOpts.Brief)
330           OS << format(" [%u] %c", abbrCode,
331                        AbbrevDecl->hasChildren() ? '*' : ' ');
332         OS << '\n';
333 
334         // Dump all data in the DIE for the attributes.
335         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
336           if (AttrSpec.Form == DW_FORM_implicit_const) {
337             // We are dumping .debug_info section ,
338             // implicit_const attribute values are not really stored here,
339             // but in .debug_abbrev section. So we just skip such attrs.
340             continue;
341           }
342           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
343                         Indent, DumpOpts);
344         }
345 
346         DWARFDie child = getFirstChild();
347         if (RecurseDepth > 0 && child) {
348           while (child) {
349             child.dump(OS, RecurseDepth-1, Indent+2, DumpOpts);
350             child = child.getSibling();
351           }
352         }
353       } else {
354         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
355         << abbrCode << '\n';
356       }
357     } else {
358       OS.indent(Indent) << "NULL\n";
359     }
360   }
361 }
362 
363 DWARFDie DWARFDie::getParent() const {
364   if (isValid())
365     return U->getParent(Die);
366   return DWARFDie();
367 }
368 
369 DWARFDie DWARFDie::getSibling() const {
370   if (isValid())
371     return U->getSibling(Die);
372   return DWARFDie();
373 }
374 
375 iterator_range<DWARFDie::attribute_iterator>
376 DWARFDie::attributes() const {
377   return make_range(attribute_iterator(*this, false),
378                     attribute_iterator(*this, true));
379 }
380 
381 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End) :
382     Die(D), AttrValue(0), Index(0) {
383   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
384   assert(AbbrDecl && "Must have abbreviation declaration");
385   if (End) {
386     // This is the end iterator so we set the index to the attribute count.
387     Index = AbbrDecl->getNumAttributes();
388   } else {
389     // This is the begin iterator so we extract the value for this->Index.
390     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
391     updateForIndex(*AbbrDecl, 0);
392   }
393 }
394 
395 void DWARFDie::attribute_iterator::updateForIndex(
396     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
397   Index = I;
398   // AbbrDecl must be valid befor calling this function.
399   auto NumAttrs = AbbrDecl.getNumAttributes();
400   if (Index < NumAttrs) {
401     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
402     // Add the previous byte size of any previous attribute value.
403     AttrValue.Offset += AttrValue.ByteSize;
404     AttrValue.Value.setForm(AbbrDecl.getFormByIndex(Index));
405     uint32_t ParseOffset = AttrValue.Offset;
406     auto U = Die.getDwarfUnit();
407     assert(U && "Die must have valid DWARF unit");
408     bool b = AttrValue.Value.extractValue(U->getDebugInfoExtractor(),
409                                           &ParseOffset, U);
410     (void)b;
411     assert(b && "extractValue cannot fail on fully parsed DWARF");
412     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
413   } else {
414     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
415     AttrValue.clear();
416   }
417 }
418 
419 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
420   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
421     updateForIndex(*AbbrDecl, Index + 1);
422   return *this;
423 }
424