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.
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 
36 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 
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 
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 
111 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       // The signature references aren't handled.
166       formValue.getForm() != DW_FORM_ref_sig8) {
167     uint32_t Ref = formValue.getAsReference(u).getValue();
168     DWARFDebugInfoEntryMinimal DIE;
169     if (const DWARFUnit *RefU = findUnitAndExtractFast(DIE, u, &Ref))
170       if (const char *Ref = DIE.getName(RefU, DINameKind::LinkageName))
171         OS << " \"" << Ref << '\"';
172   } else if (attr == DW_AT_APPLE_property_attribute) {
173     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
174       dumpApplePropertyAttribute(OS, *OptVal);
175   } else if (attr == DW_AT_ranges) {
176     dumpRanges(OS, getAddressRanges(u), u->getAddressByteSize(),
177                sizeof(BaseIndent)+indent+4);
178   }
179 
180   OS << ")\n";
181 }
182 
183 bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit *U,
184                                              uint32_t *OffsetPtr) {
185   Offset = *OffsetPtr;
186   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
187   uint32_t UEndOffset = U->getNextUnitOffset();
188   if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
189     return false;
190   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
191   if (0 == AbbrCode) {
192     // NULL debug tag entry.
193     AbbrevDecl = nullptr;
194     return true;
195   }
196   AbbrevDecl = U->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
197   if (nullptr == AbbrevDecl) {
198     // Restore the original offset.
199     *OffsetPtr = Offset;
200     return false;
201   }
202   ArrayRef<uint8_t> FixedFormSizes = DWARFFormValue::getFixedFormSizes(
203       U->getAddressByteSize(), U->getVersion());
204   assert(FixedFormSizes.size() > 0);
205 
206   // Skip all data in the .debug_info for the attributes
207   for (const auto &AttrSpec : AbbrevDecl->attributes()) {
208     uint16_t Form = AttrSpec.Form;
209 
210     uint8_t FixedFormSize =
211         (Form < FixedFormSizes.size()) ? FixedFormSizes[Form] : 0;
212     if (FixedFormSize)
213       *OffsetPtr += FixedFormSize;
214     else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, U)) {
215       // Restore the original offset.
216       *OffsetPtr = Offset;
217       return false;
218     }
219   }
220   return true;
221 }
222 
223 bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
224   return getTag() == DW_TAG_subprogram;
225 }
226 
227 bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
228   uint32_t Tag = getTag();
229   return Tag == DW_TAG_subprogram ||
230          Tag == DW_TAG_inlined_subroutine;
231 }
232 
233 bool DWARFDebugInfoEntryMinimal::getAttributeValue(
234     const DWARFUnit *U, const uint16_t Attr, DWARFFormValue &FormValue) const {
235   if (!AbbrevDecl)
236     return false;
237 
238   uint32_t AttrIdx = AbbrevDecl->findAttributeIndex(Attr);
239   if (AttrIdx == -1U)
240     return false;
241 
242   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
243   uint32_t DebugInfoOffset = getOffset();
244 
245   // Skip the abbreviation code so we are at the data for the attributes
246   DebugInfoData.getULEB128(&DebugInfoOffset);
247 
248   // Skip preceding attribute values.
249   for (uint32_t i = 0; i < AttrIdx; ++i) {
250     DWARFFormValue::skipValue(AbbrevDecl->getFormByIndex(i),
251                               DebugInfoData, &DebugInfoOffset, U);
252   }
253 
254   FormValue = DWARFFormValue(AbbrevDecl->getFormByIndex(AttrIdx));
255   return FormValue.extractValue(DebugInfoData, &DebugInfoOffset, U);
256 }
257 
258 const char *DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
259     const DWARFUnit *U, const uint16_t Attr, const char *FailValue) const {
260   DWARFFormValue FormValue;
261   if (!getAttributeValue(U, Attr, FormValue))
262     return FailValue;
263   Optional<const char *> Result = FormValue.getAsCString(U);
264   return Result.hasValue() ? Result.getValue() : FailValue;
265 }
266 
267 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsAddress(
268     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
269   DWARFFormValue FormValue;
270   if (!getAttributeValue(U, Attr, FormValue))
271     return FailValue;
272   Optional<uint64_t> Result = FormValue.getAsAddress(U);
273   return Result.hasValue() ? Result.getValue() : FailValue;
274 }
275 
276 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsignedConstant(
277     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
278   DWARFFormValue FormValue;
279   if (!getAttributeValue(U, Attr, FormValue))
280     return FailValue;
281   Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
282   return Result.hasValue() ? Result.getValue() : FailValue;
283 }
284 
285 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
286     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
287   DWARFFormValue FormValue;
288   if (!getAttributeValue(U, Attr, FormValue))
289     return FailValue;
290   Optional<uint64_t> Result = FormValue.getAsReference(U);
291   return Result.hasValue() ? Result.getValue() : FailValue;
292 }
293 
294 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
295     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
296   DWARFFormValue FormValue;
297   if (!getAttributeValue(U, Attr, FormValue))
298     return FailValue;
299   Optional<uint64_t> Result = FormValue.getAsSectionOffset();
300   return Result.hasValue() ? Result.getValue() : FailValue;
301 }
302 
303 uint64_t
304 DWARFDebugInfoEntryMinimal::getRangesBaseAttribute(const DWARFUnit *U,
305                                                    uint64_t FailValue) const {
306   uint64_t Result =
307       getAttributeValueAsSectionOffset(U, DW_AT_ranges_base, -1ULL);
308   if (Result != -1ULL)
309     return Result;
310   return getAttributeValueAsSectionOffset(U, DW_AT_GNU_ranges_base, FailValue);
311 }
312 
313 bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
314                                                  uint64_t &LowPC,
315                                                  uint64_t &HighPC) const {
316   LowPC = getAttributeValueAsAddress(U, DW_AT_low_pc, -1ULL);
317   if (LowPC == -1ULL)
318     return false;
319   HighPC = getAttributeValueAsAddress(U, DW_AT_high_pc, -1ULL);
320   if (HighPC == -1ULL) {
321     // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
322     // it represents function size.
323     HighPC = getAttributeValueAsUnsignedConstant(U, DW_AT_high_pc, -1ULL);
324     if (HighPC != -1ULL)
325       HighPC += LowPC;
326   }
327   return (HighPC != -1ULL);
328 }
329 
330 DWARFAddressRangesVector
331 DWARFDebugInfoEntryMinimal::getAddressRanges(const DWARFUnit *U) const {
332   if (isNULL())
333     return DWARFAddressRangesVector();
334   // Single range specified by low/high PC.
335   uint64_t LowPC, HighPC;
336   if (getLowAndHighPC(U, LowPC, HighPC)) {
337     return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
338   }
339   // Multiple ranges from .debug_ranges section.
340   uint32_t RangesOffset =
341       getAttributeValueAsSectionOffset(U, DW_AT_ranges, -1U);
342   if (RangesOffset != -1U) {
343     DWARFDebugRangeList RangeList;
344     if (U->extractRangeList(RangesOffset, RangeList))
345       return RangeList.getAbsoluteRanges(U->getBaseAddress());
346   }
347   return DWARFAddressRangesVector();
348 }
349 
350 void DWARFDebugInfoEntryMinimal::collectChildrenAddressRanges(
351     const DWARFUnit *U, DWARFAddressRangesVector& Ranges) const {
352   if (isNULL())
353     return;
354   if (isSubprogramDIE()) {
355     const auto &DIERanges = getAddressRanges(U);
356     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
357   }
358 
359   const DWARFDebugInfoEntryMinimal *Child = getFirstChild();
360   while (Child) {
361     Child->collectChildrenAddressRanges(U, Ranges);
362     Child = Child->getSibling();
363   }
364 }
365 
366 bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
367     const DWARFUnit *U, const uint64_t Address) const {
368   for (const auto& R : getAddressRanges(U)) {
369     if (R.first <= Address && Address < R.second)
370       return true;
371   }
372   return false;
373 }
374 
375 const char *
376 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
377                                               DINameKind Kind) const {
378   if (!isSubroutineDIE())
379     return nullptr;
380   return getName(U, Kind);
381 }
382 
383 const char *
384 DWARFDebugInfoEntryMinimal::getName(const DWARFUnit *U,
385                                     DINameKind Kind) const {
386   if (Kind == DINameKind::None)
387     return nullptr;
388   // Try to get mangled name only if it was asked for.
389   if (Kind == DINameKind::LinkageName) {
390     if (const char *name =
391             getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
392       return name;
393     if (const char *name =
394             getAttributeValueAsString(U, DW_AT_linkage_name, nullptr))
395       return name;
396   }
397   if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
398     return name;
399   // Try to get name from specification DIE.
400   uint32_t spec_ref =
401       getAttributeValueAsReference(U, DW_AT_specification, -1U);
402   if (spec_ref != -1U) {
403     DWARFDebugInfoEntryMinimal spec_die;
404     if (const DWARFUnit *RefU = findUnitAndExtractFast(spec_die, U, &spec_ref)) {
405       if (const char *name = spec_die.getName(RefU, Kind))
406         return name;
407     }
408   }
409   // Try to get name from abstract origin DIE.
410   uint32_t abs_origin_ref =
411       getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
412   if (abs_origin_ref != -1U) {
413     DWARFDebugInfoEntryMinimal abs_origin_die;
414     if (const DWARFUnit *RefU = findUnitAndExtractFast(abs_origin_die, U,
415                                                        &abs_origin_ref)) {
416       if (const char *name = abs_origin_die.getName(RefU, Kind))
417         return name;
418     }
419   }
420   return nullptr;
421 }
422 
423 void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
424                                                 uint32_t &CallFile,
425                                                 uint32_t &CallLine,
426                                                 uint32_t &CallColumn) const {
427   CallFile = getAttributeValueAsUnsignedConstant(U, DW_AT_call_file, 0);
428   CallLine = getAttributeValueAsUnsignedConstant(U, DW_AT_call_line, 0);
429   CallColumn = getAttributeValueAsUnsignedConstant(U, DW_AT_call_column, 0);
430 }
431 
432 DWARFDebugInfoEntryInlinedChain
433 DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
434     const DWARFUnit *U, const uint64_t Address) const {
435   DWARFDebugInfoEntryInlinedChain InlinedChain;
436   InlinedChain.U = U;
437   if (isNULL())
438     return InlinedChain;
439   for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
440     // Append current DIE to inlined chain only if it has correct tag
441     // (e.g. it is not a lexical block).
442     if (DIE->isSubroutineDIE()) {
443       InlinedChain.DIEs.push_back(*DIE);
444     }
445     // Try to get child which also contains provided address.
446     const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
447     while (Child) {
448       if (Child->addressRangeContainsAddress(U, Address)) {
449         // Assume there is only one such child.
450         break;
451       }
452       Child = Child->getSibling();
453     }
454     DIE = Child;
455   }
456   // Reverse the obtained chain to make the root of inlined chain last.
457   std::reverse(InlinedChain.DIEs.begin(), InlinedChain.DIEs.end());
458   return InlinedChain;
459 }
460