lib/DebugInfo/DWARF/DWARFDebugLoc.cpp

   1 //===- DWARFDebugLoc.cpp --------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
  10 #include "llvm/ADT/StringRef.h"
  11 #include "llvm/BinaryFormat/Dwarf.h"
  12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  13 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
  14 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
  15 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
  16 #include "llvm/Support/Compiler.h"
  17 #include "llvm/Support/Format.h"
  18 #include "llvm/Support/WithColor.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include <algorithm>
  21 #include <cinttypes>
  22 #include <cstdint>
  23
  24 using namespace llvm;
  25
  26 // When directly dumping the .debug_loc without a compile unit, we have to guess
  27 // at the DWARF version. This only affects DW_OP_call_ref, which is a rare
  28 // expression that LLVM doesn't produce. Guessing the wrong version means we
  29 // won't be able to pretty print expressions in DWARF2 binaries produced by
  30 // non-LLVM tools.
  31 static void dumpExpression(raw_ostream &OS, ArrayRef<uint8_t> Data,
  32                            bool IsLittleEndian, unsigned AddressSize,
  33                            const MCRegisterInfo *MRI, DWARFUnit *U) {
  34   DWARFDataExtractor Extractor(toStringRef(Data), IsLittleEndian, AddressSize);
  35   DWARFExpression(Extractor, dwarf::DWARF_VERSION, AddressSize).print(OS, MRI, U);
  36 }
  37
  38 void DWARFDebugLoc::LocationList::dump(raw_ostream &OS, uint64_t BaseAddress,
  39                                        bool IsLittleEndian,
  40                                        unsigned AddressSize,
  41                                        const MCRegisterInfo *MRI, DWARFUnit *U,
  42                                        DIDumpOptions DumpOpts,
  43                                        unsigned Indent) const {
  44   for (const Entry &E : Entries) {
  45     OS << '\n';
  46     OS.indent(Indent);
  47     OS << format("[0x%*.*" PRIx64 ", ", AddressSize * 2, AddressSize * 2,
  48                  BaseAddress + E.Begin);
  49     OS << format(" 0x%*.*" PRIx64 ")", AddressSize * 2, AddressSize * 2,
  50                  BaseAddress + E.End);
  51     OS << ": ";
  52
  53     dumpExpression(OS, E.Loc, IsLittleEndian, AddressSize, MRI, U);
  54   }
  55 }
  56
  57 DWARFDebugLoc::LocationList const *
  58 DWARFDebugLoc::getLocationListAtOffset(uint64_t Offset) const {
  59   auto It = partition_point(
  60       Locations, [=](const LocationList &L) { return L.Offset < Offset; });
  61   if (It != Locations.end() && It->Offset == Offset)
  62     return &(*It);
  63   return nullptr;
  64 }
  65
  66 void DWARFDebugLoc::dump(raw_ostream &OS, const MCRegisterInfo *MRI, DIDumpOptions DumpOpts,
  67                          Optional<uint64_t> Offset) const {
  68   auto DumpLocationList = [&](const LocationList &L) {
  69     OS << format("0x%8.8" PRIx64 ": ", L.Offset);
  70     L.dump(OS, 0, IsLittleEndian, AddressSize, MRI, nullptr, DumpOpts, 12);
  71     OS << "\n";
  72   };
  73
  74   if (Offset) {
  75     if (auto *L = getLocationListAtOffset(*Offset))
  76       DumpLocationList(*L);
  77     return;
  78   }
  79
  80   for (const LocationList &L : Locations) {
  81     DumpLocationList(L);
  82     if (&L != &Locations.back())
  83       OS << '\n';
  84   }
  85 }
  86
  87 Expected<DWARFDebugLoc::LocationList>
  88 DWARFDebugLoc::parseOneLocationList(const DWARFDataExtractor &Data,
  89                                     uint64_t *Offset) {
  90   LocationList LL;
  91   LL.Offset = *Offset;
  92   AddressSize = Data.getAddressSize();
  93   DataExtractor::Cursor C(*Offset);
  94
  95   // 2.6.2 Location Lists
  96   // A location list entry consists of:
  97   while (true) {
  98     Entry E;
  99
 100     // 1. A beginning address offset. ...
 101     E.Begin = Data.getRelocatedAddress(C);
 102
 103     // 2. An ending address offset. ...
 104     E.End = Data.getRelocatedAddress(C);
 105
 106     if (Error Err = C.takeError())
 107       return std::move(Err);
 108
 109     // The end of any given location list is marked by an end of list entry,
 110     // which consists of a 0 for the beginning address offset and a 0 for the
 111     // ending address offset.
 112     if (E.Begin == 0 && E.End == 0) {
 113       *Offset = C.tell();
 114       return LL;
 115     }
 116
 117     if (E.Begin != (AddressSize == 4 ? -1U : -1ULL)) {
 118       unsigned Bytes = Data.getU16(C);
 119       // A single location description describing the location of the object...
 120       Data.getU8(C, E.Loc, Bytes);
 121     }
 122
 123     LL.Entries.push_back(std::move(E));
 124   }
 125 }
 126
 127 void DWARFDebugLoc::parse(const DWARFDataExtractor &data) {
 128   IsLittleEndian = data.isLittleEndian();
 129   AddressSize = data.getAddressSize();
 130
 131   uint64_t Offset = 0;
 132   while (Offset < data.getData().size()) {
 133     if (auto LL = parseOneLocationList(data, &Offset))
 134       Locations.push_back(std::move(*LL));
 135     else {
 136       logAllUnhandledErrors(LL.takeError(), WithColor::error());
 137       break;
 138     }
 139   }
 140 }
 141
 142 Expected<DWARFDebugLoclists::LocationList>
 143 DWARFDebugLoclists::parseOneLocationList(const DataExtractor &Data,
 144                                          uint64_t *Offset, unsigned Version) {
 145   LocationList LL;
 146   LL.Offset = *Offset;
 147   DataExtractor::Cursor C(*Offset);
 148
 149   // dwarf::DW_LLE_end_of_list_entry is 0 and indicates the end of the list.
 150   while (auto Kind = Data.getU8(C)) {
 151     Entry E;
 152     E.Kind = Kind;
 153     E.Offset = C.tell() - 1;
 154     switch (Kind) {
 155     case dwarf::DW_LLE_base_addressx:
 156       E.Value0 = Data.getULEB128(C);
 157       break;
 158     case dwarf::DW_LLE_startx_length:
 159       E.Value0 = Data.getULEB128(C);
 160       // Pre-DWARF 5 has different interpretation of the length field. We have
 161       // to support both pre- and standartized styles for the compatibility.
 162       if (Version < 5)
 163         E.Value1 = Data.getU32(C);
 164       else
 165         E.Value1 = Data.getULEB128(C);
 166       break;
 167     case dwarf::DW_LLE_start_length:
 168       E.Value0 = Data.getAddress(C);
 169       E.Value1 = Data.getULEB128(C);
 170       break;
 171     case dwarf::DW_LLE_offset_pair:
 172       E.Value0 = Data.getULEB128(C);
 173       E.Value1 = Data.getULEB128(C);
 174       break;
 175     case dwarf::DW_LLE_base_address:
 176       E.Value0 = Data.getAddress(C);
 177       break;
 178     default:
 179       cantFail(C.takeError());
 180       return createStringError(errc::illegal_byte_sequence,
 181                                "LLE of kind %x not supported", (int)Kind);
 182     }
 183
 184     if (Kind != dwarf::DW_LLE_base_address &&
 185         Kind != dwarf::DW_LLE_base_addressx) {
 186       unsigned Bytes = Version >= 5 ? Data.getULEB128(C) : Data.getU16(C);
 187       // A single location description describing the location of the object...
 188       Data.getU8(C, E.Loc, Bytes);
 189     }
 190
 191     LL.Entries.push_back(std::move(E));
 192   }
 193   if (Error Err = C.takeError())
 194     return std::move(Err);
 195   Entry E;
 196   E.Kind = dwarf::DW_LLE_end_of_list;
 197   E.Offset = C.tell() - 1;
 198   LL.Entries.push_back(E);
 199   *Offset = C.tell();
 200   return LL;
 201 }
 202
 203 void DWARFDebugLoclists::parse(DataExtractor data, uint64_t Offset, uint64_t EndOffset, uint16_t Version) {
 204   IsLittleEndian = data.isLittleEndian();
 205   AddressSize = data.getAddressSize();
 206
 207   while (Offset < EndOffset) {
 208     if (auto LL = parseOneLocationList(data, &Offset, Version))
 209       Locations.push_back(std::move(*LL));
 210     else {
 211       logAllUnhandledErrors(LL.takeError(), WithColor::error());
 212       return;
 213     }
 214   }
 215 }
 216
 217 DWARFDebugLoclists::LocationList const *
 218 DWARFDebugLoclists::getLocationListAtOffset(uint64_t Offset) const {
 219   auto It = partition_point(
 220       Locations, [=](const LocationList &L) { return L.Offset < Offset; });
 221   if (It != Locations.end() && It->Offset == Offset)
 222     return &(*It);
 223   return nullptr;
 224 }
 225
 226 void DWARFDebugLoclists::Entry::dump(raw_ostream &OS, uint64_t &BaseAddr,
 227                                      bool IsLittleEndian, unsigned AddressSize,
 228                                      const MCRegisterInfo *MRI, DWARFUnit *U,
 229                                      DIDumpOptions DumpOpts, unsigned Indent,
 230                                      size_t MaxEncodingStringLength) const {
 231   if (DumpOpts.Verbose) {
 232     OS << "\n";
 233     OS.indent(Indent);
 234     auto EncodingString = dwarf::LocListEncodingString(Kind);
 235     // Unsupported encodings should have been reported during parsing.
 236     assert(!EncodingString.empty() && "Unknown loclist entry encoding");
 237     OS << format("%s%*c", EncodingString.data(),
 238                  MaxEncodingStringLength - EncodingString.size() + 1, '(');
 239     switch (Kind) {
 240     case dwarf::DW_LLE_startx_length:
 241     case dwarf::DW_LLE_start_length:
 242     case dwarf::DW_LLE_offset_pair:
 243       OS << format("0x%*.*" PRIx64 ", 0x%*.*" PRIx64, AddressSize * 2,
 244                  AddressSize * 2, Value0, AddressSize * 2, AddressSize * 2,
 245                  Value1);
 246       break;
 247     case dwarf::DW_LLE_base_addressx:
 248     case dwarf::DW_LLE_base_address:
 249       OS << format("0x%*.*" PRIx64, AddressSize * 2, AddressSize * 2,
 250                    Value0);
 251       break;
 252     case dwarf::DW_LLE_end_of_list:
 253       break;
 254     }
 255     OS << ')';
 256   }
 257   auto PrintPrefix = [&] {
 258     OS << "\n";
 259     OS.indent(Indent);
 260     if (DumpOpts.Verbose)
 261       OS << format("%*s", MaxEncodingStringLength, (const char *)"=> ");
 262   };
 263   switch (Kind) {
 264   case dwarf::DW_LLE_startx_length:
 265     PrintPrefix();
 266     OS << "Addr idx " << Value0 << " (w/ length " << Value1 << "): ";
 267     break;
 268   case dwarf::DW_LLE_start_length:
 269     PrintPrefix();
 270     DWARFAddressRange(Value0, Value0 + Value1)
 271         .dump(OS, AddressSize, DumpOpts);
 272     OS << ": ";
 273     break;
 274   case dwarf::DW_LLE_offset_pair:
 275     PrintPrefix();
 276     DWARFAddressRange(BaseAddr + Value0, BaseAddr + Value1)
 277         .dump(OS, AddressSize, DumpOpts);
 278     OS << ": ";
 279     break;
 280   case dwarf::DW_LLE_base_addressx:
 281     if (!DumpOpts.Verbose)
 282       return;
 283     break;
 284   case dwarf::DW_LLE_end_of_list:
 285     if (!DumpOpts.Verbose)
 286       return;
 287     break;
 288   case dwarf::DW_LLE_base_address:
 289     BaseAddr = Value0;
 290     if (!DumpOpts.Verbose)
 291       return;
 292     break;
 293   default:
 294     llvm_unreachable("unreachable locations list kind");
 295   }
 296
 297   dumpExpression(OS, Loc, IsLittleEndian, AddressSize, MRI, U);
 298 }
 299 void DWARFDebugLoclists::LocationList::dump(raw_ostream &OS, uint64_t BaseAddr,
 300                                             bool IsLittleEndian,
 301                                             unsigned AddressSize,
 302                                             const MCRegisterInfo *MRI,
 303                                             DWARFUnit *U,
 304                                             DIDumpOptions DumpOpts,
 305                                             unsigned Indent) const {
 306   size_t MaxEncodingStringLength = 0;
 307   if (DumpOpts.Verbose)
 308     for (const auto &Entry : Entries)
 309       MaxEncodingStringLength =
 310           std::max(MaxEncodingStringLength,
 311                    dwarf::LocListEncodingString(Entry.Kind).size());
 312
 313   for (const Entry &E : Entries)
 314     E.dump(OS, BaseAddr, IsLittleEndian, AddressSize, MRI, U, DumpOpts, Indent,
 315            MaxEncodingStringLength);
 316 }
 317
 318 void DWARFDebugLoclists::dump(raw_ostream &OS, uint64_t BaseAddr,
 319                               const MCRegisterInfo *MRI, DIDumpOptions DumpOpts,
 320                               Optional<uint64_t> Offset) const {
 321   auto DumpLocationList = [&](const LocationList &L) {
 322     OS << format("0x%8.8" PRIx64 ": ", L.Offset);
 323     L.dump(OS, BaseAddr, IsLittleEndian, AddressSize, MRI, nullptr, DumpOpts,
 324            /*Indent=*/12);
 325     OS << "\n";
 326   };
 327
 328   if (Offset) {
 329     if (auto *L = getLocationListAtOffset(*Offset))
 330       DumpLocationList(*L);
 331     return;
 332   }
 333
 334   for (const LocationList &L : Locations) {
 335     DumpLocationList(L);
 336     if (&L != &Locations.back())
 337       OS << '\n';
 338   }
 339 }