Line data Source code
1 : //===- SymbolizableObjectFile.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 : // Implementation of SymbolizableObjectFile class.
11 : //
12 : //===----------------------------------------------------------------------===//
13 :
14 : #include "SymbolizableObjectFile.h"
15 : #include "llvm/ADT/STLExtras.h"
16 : #include "llvm/ADT/StringRef.h"
17 : #include "llvm/ADT/Triple.h"
18 : #include "llvm/BinaryFormat/COFF.h"
19 : #include "llvm/DebugInfo/DWARF/DWARFContext.h"
20 : #include "llvm/DebugInfo/Symbolize/SymbolizableModule.h"
21 : #include "llvm/Object/COFF.h"
22 : #include "llvm/Object/ObjectFile.h"
23 : #include "llvm/Object/SymbolSize.h"
24 : #include "llvm/Support/Casting.h"
25 : #include "llvm/Support/DataExtractor.h"
26 : #include "llvm/Support/Error.h"
27 : #include <algorithm>
28 : #include <cstdint>
29 : #include <memory>
30 : #include <string>
31 : #include <system_error>
32 : #include <utility>
33 : #include <vector>
34 :
35 : using namespace llvm;
36 : using namespace object;
37 : using namespace symbolize;
38 :
39 : static DILineInfoSpecifier
40 : getDILineInfoSpecifier(FunctionNameKind FNKind) {
41 : return DILineInfoSpecifier(
42 : DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FNKind);
43 : }
44 :
45 : ErrorOr<std::unique_ptr<SymbolizableObjectFile>>
46 202 : SymbolizableObjectFile::create(object::ObjectFile *Obj,
47 : std::unique_ptr<DIContext> DICtx) {
48 : std::unique_ptr<SymbolizableObjectFile> res(
49 202 : new SymbolizableObjectFile(Obj, std::move(DICtx)));
50 : std::unique_ptr<DataExtractor> OpdExtractor;
51 : uint64_t OpdAddress = 0;
52 : // Find the .opd (function descriptor) section if any, for big-endian
53 : // PowerPC64 ELF.
54 202 : if (Obj->getArch() == Triple::ppc64) {
55 5 : for (section_iterator Section : Obj->sections()) {
56 5 : StringRef Name;
57 5 : StringRef Data;
58 5 : if (auto EC = Section->getName(Name))
59 : return EC;
60 : if (Name == ".opd") {
61 1 : if (auto EC = Section->getContents(Data))
62 : return EC;
63 1 : OpdExtractor.reset(new DataExtractor(Data, Obj->isLittleEndian(),
64 1 : Obj->getBytesInAddress()));
65 1 : OpdAddress = Section->getAddress();
66 1 : break;
67 : }
68 : }
69 : }
70 : std::vector<std::pair<SymbolRef, uint64_t>> Symbols =
71 202 : computeSymbolSizes(*Obj);
72 13172129 : for (auto &P : Symbols)
73 13171927 : res->addSymbol(P.first, P.second, OpdExtractor.get(), OpdAddress);
74 :
75 : // If this is a COFF object and we didn't find any symbols, try the export
76 : // table.
77 202 : if (Symbols.empty()) {
78 : if (auto *CoffObj = dyn_cast<COFFObjectFile>(Obj))
79 0 : if (auto EC = res->addCoffExportSymbols(CoffObj))
80 0 : return EC;
81 : }
82 : return std::move(res);
83 : }
84 :
85 202 : SymbolizableObjectFile::SymbolizableObjectFile(ObjectFile *Obj,
86 202 : std::unique_ptr<DIContext> DICtx)
87 404 : : Module(Obj), DebugInfoContext(std::move(DICtx)) {}
88 :
89 : namespace {
90 :
91 : struct OffsetNamePair {
92 : uint32_t Offset;
93 : StringRef Name;
94 :
95 0 : bool operator<(const OffsetNamePair &R) const {
96 0 : return Offset < R.Offset;
97 : }
98 : };
99 :
100 : } // end anonymous namespace
101 :
102 0 : std::error_code SymbolizableObjectFile::addCoffExportSymbols(
103 : const COFFObjectFile *CoffObj) {
104 : // Get all export names and offsets.
105 : std::vector<OffsetNamePair> ExportSyms;
106 0 : for (const ExportDirectoryEntryRef &Ref : CoffObj->export_directories()) {
107 0 : StringRef Name;
108 : uint32_t Offset;
109 0 : if (auto EC = Ref.getSymbolName(Name))
110 0 : return EC;
111 0 : if (auto EC = Ref.getExportRVA(Offset))
112 0 : return EC;
113 0 : ExportSyms.push_back(OffsetNamePair{Offset, Name});
114 : }
115 0 : if (ExportSyms.empty())
116 0 : return std::error_code();
117 :
118 : // Sort by ascending offset.
119 : array_pod_sort(ExportSyms.begin(), ExportSyms.end());
120 :
121 : // Approximate the symbol sizes by assuming they run to the next symbol.
122 : // FIXME: This assumes all exports are functions.
123 0 : uint64_t ImageBase = CoffObj->getImageBase();
124 0 : for (auto I = ExportSyms.begin(), E = ExportSyms.end(); I != E; ++I) {
125 : OffsetNamePair &Export = *I;
126 : // FIXME: The last export has a one byte size now.
127 0 : uint32_t NextOffset = I != E ? I->Offset : Export.Offset + 1;
128 0 : uint64_t SymbolStart = ImageBase + Export.Offset;
129 0 : uint64_t SymbolSize = NextOffset - Export.Offset;
130 : SymbolDesc SD = {SymbolStart, SymbolSize};
131 0 : Functions.insert(std::make_pair(SD, Export.Name));
132 : }
133 0 : return std::error_code();
134 : }
135 :
136 13171927 : std::error_code SymbolizableObjectFile::addSymbol(const SymbolRef &Symbol,
137 : uint64_t SymbolSize,
138 : DataExtractor *OpdExtractor,
139 : uint64_t OpdAddress) {
140 : Expected<SymbolRef::Type> SymbolTypeOrErr = Symbol.getType();
141 13171927 : if (!SymbolTypeOrErr)
142 0 : return errorToErrorCode(SymbolTypeOrErr.takeError());
143 13171927 : SymbolRef::Type SymbolType = *SymbolTypeOrErr;
144 13171927 : if (SymbolType != SymbolRef::ST_Function && SymbolType != SymbolRef::ST_Data)
145 44665 : return std::error_code();
146 : Expected<uint64_t> SymbolAddressOrErr = Symbol.getAddress();
147 13127262 : if (!SymbolAddressOrErr)
148 0 : return errorToErrorCode(SymbolAddressOrErr.takeError());
149 13127262 : uint64_t SymbolAddress = *SymbolAddressOrErr;
150 13127262 : if (OpdExtractor) {
151 : // For big-endian PowerPC64 ELF, symbols in the .opd section refer to
152 : // function descriptors. The first word of the descriptor is a pointer to
153 : // the function's code.
154 : // For the purposes of symbolization, pretend the symbol's address is that
155 : // of the function's code, not the descriptor.
156 3 : uint64_t OpdOffset = SymbolAddress - OpdAddress;
157 3 : uint32_t OpdOffset32 = OpdOffset;
158 3 : if (OpdOffset == OpdOffset32 &&
159 : OpdExtractor->isValidOffsetForAddress(OpdOffset32))
160 : SymbolAddress = OpdExtractor->getAddress(&OpdOffset32);
161 : }
162 : Expected<StringRef> SymbolNameOrErr = Symbol.getName();
163 13127262 : if (!SymbolNameOrErr)
164 0 : return errorToErrorCode(SymbolNameOrErr.takeError());
165 13127262 : StringRef SymbolName = *SymbolNameOrErr;
166 : // Mach-O symbol table names have leading underscore, skip it.
167 26254524 : if (Module->isMachO() && !SymbolName.empty() && SymbolName[0] == '_')
168 53 : SymbolName = SymbolName.drop_front();
169 : // FIXME: If a function has alias, there are two entries in symbol table
170 : // with same address size. Make sure we choose the correct one.
171 13127262 : auto &M = SymbolType == SymbolRef::ST_Function ? Functions : Objects;
172 : SymbolDesc SD = { SymbolAddress, SymbolSize };
173 13127262 : M.insert(std::make_pair(SD, SymbolName));
174 13127262 : return std::error_code();
175 : }
176 :
177 : // Return true if this is a 32-bit x86 PE COFF module.
178 428 : bool SymbolizableObjectFile::isWin32Module() const {
179 428 : auto *CoffObject = dyn_cast<COFFObjectFile>(Module);
180 0 : return CoffObject && CoffObject->getMachine() == COFF::IMAGE_FILE_MACHINE_I386;
181 : }
182 :
183 0 : uint64_t SymbolizableObjectFile::getModulePreferredBase() const {
184 0 : if (auto *CoffObject = dyn_cast<COFFObjectFile>(Module))
185 0 : return CoffObject->getImageBase();
186 : return 0;
187 : }
188 :
189 954 : bool SymbolizableObjectFile::getNameFromSymbolTable(SymbolRef::Type Type,
190 : uint64_t Address,
191 : std::string &Name,
192 : uint64_t &Addr,
193 : uint64_t &Size) const {
194 954 : const auto &SymbolMap = Type == SymbolRef::ST_Function ? Functions : Objects;
195 954 : if (SymbolMap.empty())
196 : return false;
197 : SymbolDesc SD = { Address, Address };
198 : auto SymbolIterator = SymbolMap.upper_bound(SD);
199 950 : if (SymbolIterator == SymbolMap.begin())
200 : return false;
201 : --SymbolIterator;
202 950 : if (SymbolIterator->first.Size != 0 &&
203 930 : SymbolIterator->first.Addr + SymbolIterator->first.Size <= Address)
204 : return false;
205 1898 : Name = SymbolIterator->second.str();
206 949 : Addr = SymbolIterator->first.Addr;
207 949 : Size = SymbolIterator->first.Size;
208 949 : return true;
209 : }
210 :
211 1339 : bool SymbolizableObjectFile::shouldOverrideWithSymbolTable(
212 : FunctionNameKind FNKind, bool UseSymbolTable) const {
213 : // When DWARF is used with -gline-tables-only / -gmlt, the symbol table gives
214 : // better answers for linkage names than the DIContext. Otherwise, we are
215 : // probably using PEs and PDBs, and we shouldn't do the override. PE files
216 : // generally only contain the names of exported symbols.
217 1339 : return FNKind == FunctionNameKind::LinkageName && UseSymbolTable &&
218 1339 : isa<DWARFContext>(DebugInfoContext.get());
219 : }
220 :
221 672 : DILineInfo SymbolizableObjectFile::symbolizeCode(uint64_t ModuleOffset,
222 : FunctionNameKind FNKind,
223 : bool UseSymbolTable) const {
224 672 : DILineInfo LineInfo;
225 672 : if (DebugInfoContext) {
226 672 : LineInfo = DebugInfoContext->getLineInfoForAddress(
227 672 : ModuleOffset, getDILineInfoSpecifier(FNKind));
228 : }
229 : // Override function name from symbol table if necessary.
230 672 : if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) {
231 : std::string FunctionName;
232 : uint64_t Start, Size;
233 288 : if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset,
234 : FunctionName, Start, Size)) {
235 285 : LineInfo.FunctionName = FunctionName;
236 : }
237 : }
238 672 : return LineInfo;
239 : }
240 :
241 667 : DIInliningInfo SymbolizableObjectFile::symbolizeInlinedCode(
242 : uint64_t ModuleOffset, FunctionNameKind FNKind, bool UseSymbolTable) const {
243 : DIInliningInfo InlinedContext;
244 :
245 667 : if (DebugInfoContext)
246 667 : InlinedContext = DebugInfoContext->getInliningInfoForAddress(
247 667 : ModuleOffset, getDILineInfoSpecifier(FNKind));
248 : // Make sure there is at least one frame in context.
249 667 : if (InlinedContext.getNumberOfFrames() == 0)
250 774 : InlinedContext.addFrame(DILineInfo());
251 :
252 : // Override the function name in lower frame with name from symbol table.
253 667 : if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) {
254 : std::string FunctionName;
255 : uint64_t Start, Size;
256 666 : if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset,
257 : FunctionName, Start, Size)) {
258 664 : InlinedContext.getMutableFrame(InlinedContext.getNumberOfFrames() - 1)
259 664 : ->FunctionName = FunctionName;
260 : }
261 : }
262 :
263 667 : return InlinedContext;
264 : }
265 :
266 0 : DIGlobal SymbolizableObjectFile::symbolizeData(uint64_t ModuleOffset) const {
267 : DIGlobal Res;
268 0 : getNameFromSymbolTable(SymbolRef::ST_Data, ModuleOffset, Res.Name, Res.Start,
269 0 : Res.Size);
270 0 : return Res;
271 : }
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