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 "DWARFDebugInfoEntry.h"
11 #include "DWARFCompileUnit.h"
12 #include "DWARFContext.h"
13 #include "DWARFDebugAbbrev.h"
14 #include "llvm/DebugInfo/DWARFFormValue.h"
15 #include "llvm/Support/Debug.h"
16 #include "llvm/Support/Dwarf.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/raw_ostream.h"
19 using namespace llvm;
20 using namespace dwarf;
21 
dump(raw_ostream & OS,const DWARFUnit * u,unsigned recurseDepth,unsigned indent) const22 void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, const DWARFUnit *u,
23                                       unsigned recurseDepth,
24                                       unsigned indent) const {
25   DataExtractor debug_info_data = u->getDebugInfoExtractor();
26   uint32_t offset = Offset;
27 
28   if (debug_info_data.isValidOffset(offset)) {
29     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
30 
31     OS << format("\n0x%8.8x: ", Offset);
32     if (abbrCode) {
33       if (AbbrevDecl) {
34         const char *tagString = TagString(getTag());
35         if (tagString)
36           OS.indent(indent) << tagString;
37         else
38           OS.indent(indent) << format("DW_TAG_Unknown_%x", getTag());
39         OS << format(" [%u] %c\n", abbrCode,
40                      AbbrevDecl->hasChildren() ? '*' : ' ');
41 
42         // Dump all data in the DIE for the attributes.
43         const uint32_t numAttributes = AbbrevDecl->getNumAttributes();
44         for (uint32_t i = 0; i != numAttributes; ++i) {
45           uint16_t attr = AbbrevDecl->getAttrByIndex(i);
46           uint16_t form = AbbrevDecl->getFormByIndex(i);
47           dumpAttribute(OS, u, &offset, attr, form, indent);
48         }
49 
50         const DWARFDebugInfoEntryMinimal *child = getFirstChild();
51         if (recurseDepth > 0 && child) {
52           while (child) {
53             child->dump(OS, u, recurseDepth-1, indent+2);
54             child = child->getSibling();
55           }
56         }
57       } else {
58         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
59            << abbrCode << '\n';
60       }
61     } else {
62       OS.indent(indent) << "NULL\n";
63     }
64   }
65 }
66 
dumpAttribute(raw_ostream & OS,const DWARFUnit * u,uint32_t * offset_ptr,uint16_t attr,uint16_t form,unsigned indent) const67 void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
68                                                const DWARFUnit *u,
69                                                uint32_t *offset_ptr,
70                                                uint16_t attr, uint16_t form,
71                                                unsigned indent) const {
72   OS << "            ";
73   OS.indent(indent+2);
74   const char *attrString = AttributeString(attr);
75   if (attrString)
76     OS << attrString;
77   else
78     OS << format("DW_AT_Unknown_%x", attr);
79   const char *formString = FormEncodingString(form);
80   if (formString)
81     OS << " [" << formString << ']';
82   else
83     OS << format(" [DW_FORM_Unknown_%x]", form);
84 
85   DWARFFormValue formValue(form);
86 
87   if (!formValue.extractValue(u->getDebugInfoExtractor(), offset_ptr, u))
88     return;
89 
90   OS << "\t(";
91   formValue.dump(OS, u);
92   OS << ")\n";
93 }
94 
extractFast(const DWARFUnit * U,uint32_t * OffsetPtr)95 bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFUnit *U,
96                                              uint32_t *OffsetPtr) {
97   Offset = *OffsetPtr;
98   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
99   uint32_t UEndOffset = U->getNextUnitOffset();
100   if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
101     return false;
102   uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
103   if (0 == AbbrCode) {
104     // NULL debug tag entry.
105     AbbrevDecl = NULL;
106     return true;
107   }
108   AbbrevDecl = U->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
109   if (0 == AbbrevDecl) {
110     // Restore the original offset.
111     *OffsetPtr = Offset;
112     return false;
113   }
114   ArrayRef<uint8_t> FixedFormSizes = DWARFFormValue::getFixedFormSizes(
115       U->getAddressByteSize(), U->getVersion());
116   assert(FixedFormSizes.size() > 0);
117 
118   // Skip all data in the .debug_info for the attributes
119   for (uint32_t i = 0, n = AbbrevDecl->getNumAttributes(); i < n; ++i) {
120     uint16_t Form = AbbrevDecl->getFormByIndex(i);
121 
122     uint8_t FixedFormSize =
123         (Form < FixedFormSizes.size()) ? FixedFormSizes[Form] : 0;
124     if (FixedFormSize)
125       *OffsetPtr += FixedFormSize;
126     else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, U)) {
127       // Restore the original offset.
128       *OffsetPtr = Offset;
129       return false;
130     }
131   }
132   return true;
133 }
134 
isSubprogramDIE() const135 bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
136   return getTag() == DW_TAG_subprogram;
137 }
138 
isSubroutineDIE() const139 bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
140   uint32_t Tag = getTag();
141   return Tag == DW_TAG_subprogram ||
142          Tag == DW_TAG_inlined_subroutine;
143 }
144 
getAttributeValue(const DWARFUnit * U,const uint16_t Attr,DWARFFormValue & FormValue) const145 bool DWARFDebugInfoEntryMinimal::getAttributeValue(
146     const DWARFUnit *U, const uint16_t Attr, DWARFFormValue &FormValue) const {
147   if (!AbbrevDecl)
148     return false;
149 
150   uint32_t AttrIdx = AbbrevDecl->findAttributeIndex(Attr);
151   if (AttrIdx == -1U)
152     return false;
153 
154   DataExtractor DebugInfoData = U->getDebugInfoExtractor();
155   uint32_t DebugInfoOffset = getOffset();
156 
157   // Skip the abbreviation code so we are at the data for the attributes
158   DebugInfoData.getULEB128(&DebugInfoOffset);
159 
160   // Skip preceding attribute values.
161   for (uint32_t i = 0; i < AttrIdx; ++i) {
162     DWARFFormValue::skipValue(AbbrevDecl->getFormByIndex(i),
163                               DebugInfoData, &DebugInfoOffset, U);
164   }
165 
166   FormValue = DWARFFormValue(AbbrevDecl->getFormByIndex(AttrIdx));
167   return FormValue.extractValue(DebugInfoData, &DebugInfoOffset, U);
168 }
169 
getAttributeValueAsString(const DWARFUnit * U,const uint16_t Attr,const char * FailValue) const170 const char *DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
171     const DWARFUnit *U, const uint16_t Attr, const char *FailValue) const {
172   DWARFFormValue FormValue;
173   if (!getAttributeValue(U, Attr, FormValue))
174     return FailValue;
175   Optional<const char *> Result = FormValue.getAsCString(U);
176   return Result.hasValue() ? Result.getValue() : FailValue;
177 }
178 
getAttributeValueAsAddress(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const179 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsAddress(
180     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
181   DWARFFormValue FormValue;
182   if (!getAttributeValue(U, Attr, FormValue))
183     return FailValue;
184   Optional<uint64_t> Result = FormValue.getAsAddress(U);
185   return Result.hasValue() ? Result.getValue() : FailValue;
186 }
187 
getAttributeValueAsUnsignedConstant(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const188 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsignedConstant(
189     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
190   DWARFFormValue FormValue;
191   if (!getAttributeValue(U, Attr, FormValue))
192     return FailValue;
193   Optional<uint64_t> Result = FormValue.getAsUnsignedConstant();
194   return Result.hasValue() ? Result.getValue() : FailValue;
195 }
196 
getAttributeValueAsReference(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const197 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
198     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
199   DWARFFormValue FormValue;
200   if (!getAttributeValue(U, Attr, FormValue))
201     return FailValue;
202   Optional<uint64_t> Result = FormValue.getAsReference(U);
203   return Result.hasValue() ? Result.getValue() : FailValue;
204 }
205 
getAttributeValueAsSectionOffset(const DWARFUnit * U,const uint16_t Attr,uint64_t FailValue) const206 uint64_t DWARFDebugInfoEntryMinimal::getAttributeValueAsSectionOffset(
207     const DWARFUnit *U, const uint16_t Attr, uint64_t FailValue) const {
208   DWARFFormValue FormValue;
209   if (!getAttributeValue(U, Attr, FormValue))
210     return FailValue;
211   Optional<uint64_t> Result = FormValue.getAsSectionOffset();
212   return Result.hasValue() ? Result.getValue() : FailValue;
213 }
214 
getLowAndHighPC(const DWARFUnit * U,uint64_t & LowPC,uint64_t & HighPC) const215 bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFUnit *U,
216                                                  uint64_t &LowPC,
217                                                  uint64_t &HighPC) const {
218   LowPC = getAttributeValueAsAddress(U, DW_AT_low_pc, -1ULL);
219   if (LowPC == -1ULL)
220     return false;
221   HighPC = getAttributeValueAsAddress(U, DW_AT_high_pc, -1ULL);
222   if (HighPC == -1ULL) {
223     // Since DWARF4, DW_AT_high_pc may also be of class constant, in which case
224     // it represents function size.
225     HighPC = getAttributeValueAsUnsignedConstant(U, DW_AT_high_pc, -1ULL);
226     if (HighPC != -1ULL)
227       HighPC += LowPC;
228   }
229   return (HighPC != -1ULL);
230 }
231 
buildAddressRangeTable(const DWARFUnit * U,DWARFDebugAranges * DebugAranges,uint32_t UOffsetInAranges) const232 void DWARFDebugInfoEntryMinimal::buildAddressRangeTable(
233     const DWARFUnit *U, DWARFDebugAranges *DebugAranges,
234     uint32_t UOffsetInAranges) const {
235   if (AbbrevDecl) {
236     if (isSubprogramDIE()) {
237       uint64_t LowPC, HighPC;
238       if (getLowAndHighPC(U, LowPC, HighPC))
239         DebugAranges->appendRange(UOffsetInAranges, LowPC, HighPC);
240       // FIXME: try to append ranges from .debug_ranges section.
241     }
242 
243     const DWARFDebugInfoEntryMinimal *Child = getFirstChild();
244     while (Child) {
245       Child->buildAddressRangeTable(U, DebugAranges, UOffsetInAranges);
246       Child = Child->getSibling();
247     }
248   }
249 }
250 
addressRangeContainsAddress(const DWARFUnit * U,const uint64_t Address) const251 bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
252     const DWARFUnit *U, const uint64_t Address) const {
253   if (isNULL())
254     return false;
255   uint64_t LowPC, HighPC;
256   if (getLowAndHighPC(U, LowPC, HighPC))
257     return (LowPC <= Address && Address <= HighPC);
258   // Try to get address ranges from .debug_ranges section.
259   uint32_t RangesOffset =
260       getAttributeValueAsSectionOffset(U, DW_AT_ranges, -1U);
261   if (RangesOffset != -1U) {
262     DWARFDebugRangeList RangeList;
263     if (U->extractRangeList(RangesOffset, RangeList))
264       return RangeList.containsAddress(U->getBaseAddress(), Address);
265   }
266   return false;
267 }
268 
269 const char *
getSubroutineName(const DWARFUnit * U) const270 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U) const {
271   if (!isSubroutineDIE())
272     return 0;
273   // Try to get mangled name if possible.
274   if (const char *name =
275       getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, 0))
276     return name;
277   if (const char *name = getAttributeValueAsString(U, DW_AT_linkage_name, 0))
278     return name;
279   if (const char *name = getAttributeValueAsString(U, DW_AT_name, 0))
280     return name;
281   // Try to get name from specification DIE.
282   uint32_t spec_ref =
283       getAttributeValueAsReference(U, DW_AT_specification, -1U);
284   if (spec_ref != -1U) {
285     DWARFDebugInfoEntryMinimal spec_die;
286     if (spec_die.extractFast(U, &spec_ref)) {
287       if (const char *name = spec_die.getSubroutineName(U))
288         return name;
289     }
290   }
291   // Try to get name from abstract origin DIE.
292   uint32_t abs_origin_ref =
293       getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
294   if (abs_origin_ref != -1U) {
295     DWARFDebugInfoEntryMinimal abs_origin_die;
296     if (abs_origin_die.extractFast(U, &abs_origin_ref)) {
297       if (const char *name = abs_origin_die.getSubroutineName(U))
298         return name;
299     }
300   }
301   return 0;
302 }
303 
getCallerFrame(const DWARFUnit * U,uint32_t & CallFile,uint32_t & CallLine,uint32_t & CallColumn) const304 void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFUnit *U,
305                                                 uint32_t &CallFile,
306                                                 uint32_t &CallLine,
307                                                 uint32_t &CallColumn) const {
308   CallFile = getAttributeValueAsUnsignedConstant(U, DW_AT_call_file, 0);
309   CallLine = getAttributeValueAsUnsignedConstant(U, DW_AT_call_line, 0);
310   CallColumn = getAttributeValueAsUnsignedConstant(U, DW_AT_call_column, 0);
311 }
312 
313 DWARFDebugInfoEntryInlinedChain
getInlinedChainForAddress(const DWARFUnit * U,const uint64_t Address) const314 DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
315     const DWARFUnit *U, const uint64_t Address) const {
316   DWARFDebugInfoEntryInlinedChain InlinedChain;
317   InlinedChain.U = U;
318   if (isNULL())
319     return InlinedChain;
320   for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
321     // Append current DIE to inlined chain only if it has correct tag
322     // (e.g. it is not a lexical block).
323     if (DIE->isSubroutineDIE()) {
324       InlinedChain.DIEs.push_back(*DIE);
325     }
326     // Try to get child which also contains provided address.
327     const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
328     while (Child) {
329       if (Child->addressRangeContainsAddress(U, Address)) {
330         // Assume there is only one such child.
331         break;
332       }
333       Child = Child->getSibling();
334     }
335     DIE = Child;
336   }
337   // Reverse the obtained chain to make the root of inlined chain last.
338   std::reverse(InlinedChain.DIEs.begin(), InlinedChain.DIEs.end());
339   return InlinedChain;
340 }
341