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         auto tagString = TagString(getTag());
49         if (!tagString.empty())
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     auto PropName = ApplePropertyString(Bit);
87     if (!PropName.empty())
88       OS << PropName;
89     else
90       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
91     if (!(Val ^= Bit))
92       break;
93     OS << ", ";
94   } while (true);
95   OS << ")";
96 }
97 
98 static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
99                        unsigned AddressSize, unsigned Indent) {
100   if (Ranges.empty())
101     return;
102 
103   for (const auto &Range: Ranges) {
104     OS << '\n';
105     OS.indent(Indent);
106     OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
107                  AddressSize*2, Range.first,
108                  AddressSize*2, Range.second);
109   }
110 }
111 
112 void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
113                                                DWARFUnit *u,
114                                                uint32_t *offset_ptr,
115                                                dwarf::Attribute attr,
116                                                dwarf::Form form,
117                                                unsigned indent) const {
118   const char BaseIndent[] = "            ";
119   OS << BaseIndent;
120   OS.indent(indent+2);
121   auto attrString = AttributeString(attr);
122   if (!attrString.empty())
123     WithColor(OS, syntax::Attribute) << attrString;
124   else
125     WithColor(OS, syntax::Attribute).get() << format("DW_AT_Unknown_%x", attr);
126 
127   auto formString = FormEncodingString(form);
128   if (!formString.empty())
129     OS << " [" << formString << ']';
130   else
131     OS << format(" [DW_FORM_Unknown_%x]", form);
132 
133   DWARFFormValue formValue(form);
134 
135   if (!formValue.extractValue(u->getDebugInfoExtractor(), offset_ptr, u))
136     return;
137 
138   OS << "\t(";
139 
140   StringRef Name;
141   std::string File;
142   auto Color = syntax::Enumerator;
143   if (attr == DW_AT_decl_file || attr == DW_AT_call_file) {
144     Color = syntax::String;
145     if (const auto *LT = u->getContext().getLineTableForUnit(u))
146       if (LT->getFileNameByIndex(
147              formValue.getAsUnsignedConstant().getValue(),
148              u->getCompilationDir(),
149              DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
150         File = '"' + File + '"';
151         Name = File;
152       }
153   } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
154     Name = AttributeValueString(attr, *Val);
155 
156   if (!Name.empty())
157     WithColor(OS, Color) << Name;
158   else if (attr == DW_AT_decl_line || attr == DW_AT_call_line)
159     OS << *formValue.getAsUnsignedConstant();
160   else
161     formValue.dump(OS);
162 
163   // We have dumped the attribute raw value. For some attributes
164   // having both the raw value and the pretty-printed value is
165   // interesting. These attributes are handled below.
166   if (attr == DW_AT_specification || attr == DW_AT_abstract_origin) {
167     Optional<uint64_t> Ref = formValue.getAsReference();
168     if (Ref.hasValue()) {
169       uint32_t RefOffset = Ref.getValue();
170       DWARFDebugInfoEntryMinimal DIE;
171       if (const DWARFUnit *RefU = findUnitAndExtractFast(DIE, u, &RefOffset))
172         if (const char *Name = DIE.getName(RefU, DINameKind::LinkageName))
173           OS << " \"" << Name << '\"';
174     }
175   } else if (attr == DW_AT_APPLE_property_attribute) {
176     if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
177       dumpApplePropertyAttribute(OS, *OptVal);
178   } else if (attr == DW_AT_ranges) {
179     dumpRanges(OS, getAddressRanges(u), u->getAddressByteSize(),
180                sizeof(BaseIndent)+indent+4);
181   }
182 
183   OS << ")\n";
184 }
185 
186 bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit &U,
187                                              uint32_t *OffsetPtr) {
188   DataExtractor DebugInfoData = U.getDebugInfoExtractor();
189   const uint32_t UEndOffset = U.getNextUnitOffset();
190   return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset);
191 }
192 bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit &U,
193                                              uint32_t *OffsetPtr,
194                                              const DataExtractor &DebugInfoData,
195                                              uint32_t UEndOffset) {
196   Offset = *OffsetPtr;
197   if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
198     return false;
199   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
200   if (0 == AbbrCode) {
201     // NULL debug tag entry.
202     AbbrevDecl = nullptr;
203     return true;
204   }
205   AbbrevDecl = U.getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
206   if (nullptr == AbbrevDecl) {
207     // Restore the original offset.
208     *OffsetPtr = Offset;
209     return false;
210   }
211   // See if all attributes in this DIE have fixed byte sizes. If so, we can
212   // just add this size to the offset to skip to the next DIE.
213   if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) {
214     *OffsetPtr += *FixedSize;
215     return true;
216   }
217 
218   // Skip all data in the .debug_info for the attributes
219   for (const auto &AttrSpec : AbbrevDecl->attributes()) {
220     // Check if this attribute has a fixed byte size.
221     if (Optional<uint8_t> FixedSize = AttrSpec.getByteSize(U)) {
222       // Attribute byte size if fixed, just add the size to the offset.
223       *OffsetPtr += *FixedSize;
224     } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
225                                           OffsetPtr, &U)) {
226       // We failed to skip this attribute's value, restore the original offset
227       // and return the failure status.
228       *OffsetPtr = Offset;
229       return false;
230     }
231   }
232   return true;
233 }
234 
235 bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
236   return getTag() == DW_TAG_subprogram;
237 }
238 
239 bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
240   uint32_t Tag = getTag();
241   return Tag == DW_TAG_subprogram ||
242          Tag == DW_TAG_inlined_subroutine;
243 }
244 
245 bool DWARFDebugInfoEntryMinimal::getAttributeValue(const DWARFUnit *U,
246     dwarf::Attribute Attr, DWARFFormValue &FormValue) const {
247   if (!AbbrevDecl || !U)
248     return false;
249   return AbbrevDecl->getAttributeValue(Offset, Attr, *U, FormValue);
250 }
251 
252 const char *DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
253     const DWARFUnit *U, dwarf::Attribute Attr,
254     const char *FailValue) const {
255   DWARFFormValue FormValue;
256   if (!getAttributeValue(U, Attr, FormValue))
257     return FailValue;
258   Optional<const char *> Result = FormValue.getAsCString();
259   return Result.hasValue() ? Result.getValue() : FailValue;
260 }
261 
262 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsAddress(
263     const DWARFUnit *U, dwarf::Attribute Attr,
264     uint64_t FailValue) const {
265   DWARFFormValue FormValue;
266   if (!getAttributeValue(U, Attr, FormValue))
267     return FailValue;
268   Optional<uint64_t> Result = FormValue.getAsAddress();
269   return Result.hasValue() ? Result.getValue() : FailValue;
270 }
271 
272 int64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSignedConstant(
273     const DWARFUnit *U, dwarf::Attribute Attr, int64_t FailValue) const {
274   DWARFFormValue FormValue;
275   if (!getAttributeValue(U, Attr, FormValue))
276     return FailValue;
277   Optional<int64_t> Result = FormValue.getAsSignedConstant();
278   return Result.hasValue() ? Result.getValue() : FailValue;
279 }
280 
281 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsignedConstant(
282     const DWARFUnit *U, dwarf::Attribute Attr,
283     uint64_t FailValue) const {
284   DWARFFormValue FormValue;
285   if (!getAttributeValue(U, Attr, FormValue))
286     return FailValue;
287   Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
288   return Result.hasValue() ? Result.getValue() : FailValue;
289 }
290 
291 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
292     const DWARFUnit *U, dwarf::Attribute Attr,
293     uint64_t FailValue) const {
294   DWARFFormValue FormValue;
295   if (!getAttributeValue(U, Attr, FormValue))
296     return FailValue;
297   Optional<uint64_t> Result = FormValue.getAsReference();
298   return Result.hasValue() ? Result.getValue() : FailValue;
299 }
300 
301 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
302     const DWARFUnit *U, dwarf::Attribute Attr,
303     uint64_t FailValue) const {
304   DWARFFormValue FormValue;
305   if (!getAttributeValue(U, Attr, FormValue))
306     return FailValue;
307   Optional<uint64_t> Result = FormValue.getAsSectionOffset();
308   return Result.hasValue() ? Result.getValue() : FailValue;
309 }
310 
311 uint64_t
312 DWARFDebugInfoEntryMinimal::getRangesBaseAttribute(const DWARFUnit *U,
313                                                    uint64_t FailValue) const {
314   uint64_t Result =
315       getAttributeValueAsSectionOffset(U, DW_AT_rnglists_base, -1ULL);
316   if (Result != -1ULL)
317     return Result;
318   return getAttributeValueAsSectionOffset(U, DW_AT_GNU_ranges_base, FailValue);
319 }
320 
321 bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
322                                                  uint64_t &LowPC,
323                                                  uint64_t &HighPC) const {
324   LowPC = getAttributeValueAsAddress(U, DW_AT_low_pc, -1ULL);
325   if (LowPC == -1ULL)
326     return false;
327   HighPC = getAttributeValueAsAddress(U, DW_AT_high_pc, -1ULL);
328   if (HighPC == -1ULL) {
329     // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
330     // it represents function size.
331     HighPC = getAttributeValueAsUnsignedConstant(U, DW_AT_high_pc, -1ULL);
332     if (HighPC != -1ULL)
333       HighPC += LowPC;
334   }
335   return (HighPC != -1ULL);
336 }
337 
338 DWARFAddressRangesVector
339 DWARFDebugInfoEntryMinimal::getAddressRanges(const DWARFUnit *U) const {
340   if (isNULL())
341     return DWARFAddressRangesVector();
342   // Single range specified by low/high PC.
343   uint64_t LowPC, HighPC;
344   if (getLowAndHighPC(U, LowPC, HighPC)) {
345     return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
346   }
347   // Multiple ranges from .debug_ranges section.
348   uint32_t RangesOffset =
349       getAttributeValueAsSectionOffset(U, DW_AT_ranges, -1U);
350   if (RangesOffset != -1U) {
351     DWARFDebugRangeList RangeList;
352     if (U->extractRangeList(RangesOffset, RangeList))
353       return RangeList.getAbsoluteRanges(U->getBaseAddress());
354   }
355   return DWARFAddressRangesVector();
356 }
357 
358 void DWARFDebugInfoEntryMinimal::collectChildrenAddressRanges(
359     const DWARFUnit *U, DWARFAddressRangesVector& Ranges) const {
360   if (isNULL())
361     return;
362   if (isSubprogramDIE()) {
363     const auto &DIERanges = getAddressRanges(U);
364     Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
365   }
366 
367   const DWARFDebugInfoEntryMinimal *Child = getFirstChild();
368   while (Child) {
369     Child->collectChildrenAddressRanges(U, Ranges);
370     Child = Child->getSibling();
371   }
372 }
373 
374 bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
375     const DWARFUnit *U, const uint64_t Address) const {
376   for (const auto& R : getAddressRanges(U)) {
377     if (R.first <= Address && Address < R.second)
378       return true;
379   }
380   return false;
381 }
382 
383 const char *
384 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
385                                               DINameKind Kind) const {
386   if (!isSubroutineDIE())
387     return nullptr;
388   return getName(U, Kind);
389 }
390 
391 const char *
392 DWARFDebugInfoEntryMinimal::getName(const DWARFUnit *U,
393                                     DINameKind Kind) const {
394   if (Kind == DINameKind::None)
395     return nullptr;
396   // Try to get mangled name only if it was asked for.
397   if (Kind == DINameKind::LinkageName) {
398     if (const char *name =
399             getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
400       return name;
401     if (const char *name =
402             getAttributeValueAsString(U, DW_AT_linkage_name, nullptr))
403       return name;
404   }
405   if (const char *name = getAttributeValueAsString(U, DW_AT_name, nullptr))
406     return name;
407   // Try to get name from specification DIE.
408   uint32_t spec_ref =
409       getAttributeValueAsReference(U, DW_AT_specification, -1U);
410   if (spec_ref != -1U) {
411     DWARFDebugInfoEntryMinimal spec_die;
412     if (const DWARFUnit *RefU = findUnitAndExtractFast(spec_die, U, &spec_ref)) {
413       if (const char *name = spec_die.getName(RefU, Kind))
414         return name;
415     }
416   }
417   // Try to get name from abstract origin DIE.
418   uint32_t abs_origin_ref =
419       getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
420   if (abs_origin_ref != -1U) {
421     DWARFDebugInfoEntryMinimal abs_origin_die;
422     if (const DWARFUnit *RefU = findUnitAndExtractFast(abs_origin_die, U,
423                                                        &abs_origin_ref)) {
424       if (const char *name = abs_origin_die.getName(RefU, Kind))
425         return name;
426     }
427   }
428   return nullptr;
429 }
430 
431 void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
432                                                 uint32_t &CallFile,
433                                                 uint32_t &CallLine,
434                                                 uint32_t &CallColumn) const {
435   CallFile = getAttributeValueAsUnsignedConstant(U, DW_AT_call_file, 0);
436   CallLine = getAttributeValueAsUnsignedConstant(U, DW_AT_call_line, 0);
437   CallColumn = getAttributeValueAsUnsignedConstant(U, DW_AT_call_column, 0);
438 }
439 
440 DWARFDebugInfoEntryInlinedChain
441 DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
442     const DWARFUnit *U, const uint64_t Address) const {
443   DWARFDebugInfoEntryInlinedChain InlinedChain;
444   InlinedChain.U = U;
445   if (isNULL())
446     return InlinedChain;
447   for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
448     // Append current DIE to inlined chain only if it has correct tag
449     // (e.g. it is not a lexical block).
450     if (DIE->isSubroutineDIE()) {
451       InlinedChain.DIEs.push_back(*DIE);
452     }
453     // Try to get child which also contains provided address.
454     const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
455     while (Child) {
456       if (Child->addressRangeContainsAddress(U, Address)) {
457         // Assume there is only one such child.
458         break;
459       }
460       Child = Child->getSibling();
461     }
462     DIE = Child;
463   }
464   // Reverse the obtained chain to make the root of inlined chain last.
465   std::reverse(InlinedChain.DIEs.begin(), InlinedChain.DIEs.end());
466   return InlinedChain;
467 }
468