lld/COFF/MapFile.cpp

   1 //===- MapFile.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 // This file implements the /map option in the same format as link.exe
  10 // (based on observations)
  11 //
  12 // Header (program name, timestamp info, preferred load address)
  13 //
  14 // Section list (Start = Section index:Base address):
  15 // Start         Length     Name                   Class
  16 // 0001:00001000 00000015H .text                   CODE
  17 //
  18 // Symbols list:
  19 // Address        Publics by Value    Rva + Base          Lib:Object
  20 // 0001:00001000  main                 0000000140001000    main.obj
  21 // 0001:00001300  ?__scrt_common_main@@YAHXZ  0000000140001300 libcmt:exe_main.obj
  22 //
  23 // entry point at        0001:00000360
  24 //
  25 // Static symbols
  26 //
  27 // 0000:00000000  __guard_fids__       0000000140000000     libcmt : exe_main.obj
  28 //===----------------------------------------------------------------------===//
  29
  30 #include "MapFile.h"
  31 #include "COFFLinkerContext.h"
  32 #include "SymbolTable.h"
  33 #include "Symbols.h"
  34 #include "Writer.h"
  35 #include "lld/Common/ErrorHandler.h"
  36 #include "lld/Common/Timer.h"
  37 #include "llvm/Support/Parallel.h"
  38 #include "llvm/Support/Path.h"
  39 #include "llvm/Support/TimeProfiler.h"
  40 #include "llvm/Support/raw_ostream.h"
  41
  42 using namespace llvm;
  43 using namespace llvm::object;
  44 using namespace lld;
  45 using namespace lld::coff;
  46
  47 // Print out the first two columns of a line.
  48 static void writeHeader(raw_ostream &os, uint32_t sec, uint64_t addr) {
  49   os << format(" %04x:%08llx", sec, addr);
  50 }
  51
  52 // Write the time stamp with the format used by link.exe
  53 // It seems identical to strftime with "%c" on msvc build, but we need a
  54 // locale-agnostic version.
  55 static void writeFormattedTimestamp(raw_ostream &os, time_t tds) {
  56   constexpr const char *const days[7] = {"Sun", "Mon", "Tue", "Wed",
  57                                          "Thu", "Fri", "Sat"};
  58   constexpr const char *const months[12] = {"Jan", "Feb", "Mar", "Apr",
  59                                             "May", "Jun", "Jul", "Aug",
  60                                             "Sep", "Oct", "Nov", "Dec"};
  61   tm *time = localtime(&tds);
  62   os << format("%s %s %2d %02d:%02d:%02d %d", days[time->tm_wday],
  63                months[time->tm_mon], time->tm_mday, time->tm_hour, time->tm_min,
  64                time->tm_sec, time->tm_year + 1900);
  65 }
  66
  67 static void sortUniqueSymbols(std::vector<Defined *> &syms,
  68                               uint64_t imageBase) {
  69   // Build helper vector
  70   using SortEntry = std::pair<Defined *, size_t>;
  71   std::vector<SortEntry> v;
  72   v.resize(syms.size());
  73   for (size_t i = 0, e = syms.size(); i < e; ++i)
  74     v[i] = SortEntry(syms[i], i);
  75
  76   // Remove duplicate symbol pointers
  77   parallelSort(v, std::less<SortEntry>());
  78   auto end = std::unique(v.begin(), v.end(),
  79                          [](const SortEntry &a, const SortEntry &b) {
  80                            return a.first == b.first;
  81                          });
  82   v.erase(end, v.end());
  83
  84   // Sort by RVA then original order
  85   parallelSort(v, [imageBase](const SortEntry &a, const SortEntry &b) {
  86     // Add config.imageBase to avoid comparing "negative" RVAs.
  87     // This can happen with symbols of Absolute kind
  88     uint64_t rvaa = imageBase + a.first->getRVA();
  89     uint64_t rvab = imageBase + b.first->getRVA();
  90     return rvaa < rvab || (rvaa == rvab && a.second < b.second);
  91   });
  92
  93   syms.resize(v.size());
  94   for (size_t i = 0, e = v.size(); i < e; ++i)
  95     syms[i] = v[i].first;
  96 }
  97
  98 // Returns the lists of all symbols that we want to print out.
  99 static void getSymbols(const COFFLinkerContext &ctx,
 100                        std::vector<Defined *> &syms,
 101                        std::vector<Defined *> &staticSyms) {
 102
 103   for (ObjFile *file : ctx.objFileInstances)
 104     for (Symbol *b : file->getSymbols()) {
 105       if (!b || !b->isLive())
 106         continue;
 107       if (auto *sym = dyn_cast<DefinedCOFF>(b)) {
 108         COFFSymbolRef symRef = sym->getCOFFSymbol();
 109         if (!symRef.isSectionDefinition() &&
 110             symRef.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL) {
 111           if (symRef.getStorageClass() == COFF::IMAGE_SYM_CLASS_STATIC)
 112             staticSyms.push_back(sym);
 113           else
 114             syms.push_back(sym);
 115         }
 116       } else if (auto *sym = dyn_cast<Defined>(b)) {
 117         syms.push_back(sym);
 118       }
 119     }
 120
 121   for (ImportFile *file : ctx.importFileInstances) {
 122     if (!file->live)
 123       continue;
 124
 125     if (!file->thunkSym)
 126       continue;
 127
 128     if (!file->thunkLive)
 129       continue;
 130
 131     if (auto *thunkSym = dyn_cast<Defined>(file->thunkSym))
 132       syms.push_back(thunkSym);
 133
 134     if (auto *impSym = dyn_cast_or_null<Defined>(file->impSym))
 135       syms.push_back(impSym);
 136   }
 137
 138   sortUniqueSymbols(syms, ctx.config.imageBase);
 139   sortUniqueSymbols(staticSyms, ctx.config.imageBase);
 140 }
 141
 142 // Construct a map from symbols to their stringified representations.
 143 static DenseMap<Defined *, std::string>
 144 getSymbolStrings(const COFFLinkerContext &ctx, ArrayRef<Defined *> syms) {
 145   std::vector<std::string> str(syms.size());
 146   parallelFor((size_t)0, syms.size(), [&](size_t i) {
 147     raw_string_ostream os(str[i]);
 148     Defined *sym = syms[i];
 149
 150     uint16_t sectionIdx = 0;
 151     uint64_t address = 0;
 152     SmallString<128> fileDescr;
 153
 154     if (auto *absSym = dyn_cast<DefinedAbsolute>(sym)) {
 155       address = absSym->getVA();
 156       fileDescr = "<absolute>";
 157     } else if (isa<DefinedSynthetic>(sym)) {
 158       fileDescr = "<linker-defined>";
 159     } else if (isa<DefinedCommon>(sym)) {
 160       fileDescr = "<common>";
 161     } else if (Chunk *chunk = sym->getChunk()) {
 162       address = sym->getRVA();
 163       if (OutputSection *sec = ctx.getOutputSection(chunk))
 164         address -= sec->header.VirtualAddress;
 165
 166       sectionIdx = chunk->getOutputSectionIdx();
 167
 168       InputFile *file;
 169       if (auto *impSym = dyn_cast<DefinedImportData>(sym))
 170         file = impSym->file;
 171       else if (auto *thunkSym = dyn_cast<DefinedImportThunk>(sym))
 172         file = thunkSym->wrappedSym->file;
 173       else
 174         file = sym->getFile();
 175
 176       if (file) {
 177         if (!file->parentName.empty()) {
 178           fileDescr = sys::path::filename(file->parentName);
 179           sys::path::replace_extension(fileDescr, "");
 180           fileDescr += ":";
 181         }
 182         fileDescr += sys::path::filename(file->getName());
 183       }
 184     }
 185     writeHeader(os, sectionIdx, address);
 186     os << "       ";
 187     os << left_justify(sym->getName(), 26);
 188     os << " ";
 189     os << format_hex_no_prefix((ctx.config.imageBase + sym->getRVA()), 16);
 190     if (!fileDescr.empty()) {
 191       os << "     "; // FIXME : Handle "f" and "i" flags sometimes generated
 192                      // by link.exe in those spaces
 193       os << fileDescr;
 194     }
 195   });
 196
 197   DenseMap<Defined *, std::string> ret;
 198   for (size_t i = 0, e = syms.size(); i < e; ++i)
 199     ret[syms[i]] = std::move(str[i]);
 200   return ret;
 201 }
 202
 203 void lld::coff::writeMapFile(COFFLinkerContext &ctx) {
 204   if (ctx.config.mapFile.empty())
 205     return;
 206
 207   llvm::TimeTraceScope timeScope("Map file");
 208   std::error_code ec;
 209   raw_fd_ostream os(ctx.config.mapFile, ec, sys::fs::OF_None);
 210   if (ec)
 211     fatal("cannot open " + ctx.config.mapFile + ": " + ec.message());
 212
 213   ScopedTimer t1(ctx.totalMapTimer);
 214
 215   // Collect symbol info that we want to print out.
 216   ScopedTimer t2(ctx.symbolGatherTimer);
 217   std::vector<Defined *> syms;
 218   std::vector<Defined *> staticSyms;
 219   getSymbols(ctx, syms, staticSyms);
 220   t2.stop();
 221
 222   ScopedTimer t3(ctx.symbolStringsTimer);
 223   DenseMap<Defined *, std::string> symStr = getSymbolStrings(ctx, syms);
 224   DenseMap<Defined *, std::string> staticSymStr =
 225       getSymbolStrings(ctx, staticSyms);
 226   t3.stop();
 227
 228   ScopedTimer t4(ctx.writeTimer);
 229   SmallString<128> AppName = sys::path::filename(ctx.config.outputFile);
 230   sys::path::replace_extension(AppName, "");
 231
 232   // Print out the file header
 233   os << " " << AppName << "\n";
 234   os << "\n";
 235
 236   os << " Timestamp is " << format_hex_no_prefix(ctx.config.timestamp, 8)
 237      << " (";
 238   if (ctx.config.repro) {
 239     os << "Repro mode";
 240   } else {
 241     writeFormattedTimestamp(os, ctx.config.timestamp);
 242   }
 243   os << ")\n";
 244
 245   os << "\n";
 246   os << " Preferred load address is "
 247      << format_hex_no_prefix(ctx.config.imageBase, 16) << "\n";
 248   os << "\n";
 249
 250   // Print out section table.
 251   os << " Start         Length     Name                   Class\n";
 252
 253   for (OutputSection *sec : ctx.outputSections) {
 254     // Merge display of chunks with same sectionName
 255     std::vector<std::pair<SectionChunk *, SectionChunk *>> ChunkRanges;
 256     for (Chunk *c : sec->chunks) {
 257       auto *sc = dyn_cast<SectionChunk>(c);
 258       if (!sc)
 259         continue;
 260
 261       if (ChunkRanges.empty() ||
 262           c->getSectionName() != ChunkRanges.back().first->getSectionName()) {
 263         ChunkRanges.emplace_back(sc, sc);
 264       } else {
 265         ChunkRanges.back().second = sc;
 266       }
 267     }
 268
 269     const bool isCodeSection =
 270         (sec->header.Characteristics & COFF::IMAGE_SCN_CNT_CODE) &&
 271         (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_READ) &&
 272         (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_EXECUTE);
 273     StringRef SectionClass = (isCodeSection ? "CODE" : "DATA");
 274
 275     for (auto &cr : ChunkRanges) {
 276       size_t size =
 277           cr.second->getRVA() + cr.second->getSize() - cr.first->getRVA();
 278
 279       auto address = cr.first->getRVA() - sec->header.VirtualAddress;
 280       writeHeader(os, sec->sectionIndex, address);
 281       os << " " << format_hex_no_prefix(size, 8) << "H";
 282       os << " " << left_justify(cr.first->getSectionName(), 23);
 283       os << " " << SectionClass;
 284       os << '\n';
 285     }
 286   }
 287
 288   // Print out the symbols table (without static symbols)
 289   os << "\n";
 290   os << "  Address         Publics by Value              Rva+Base"
 291         "               Lib:Object\n";
 292   os << "\n";
 293   for (Defined *sym : syms)
 294     os << symStr[sym] << '\n';
 295
 296   // Print out the entry point.
 297   os << "\n";
 298
 299   uint16_t entrySecIndex = 0;
 300   uint64_t entryAddress = 0;
 301
 302   if (!ctx.config.noEntry) {
 303     Defined *entry = dyn_cast_or_null<Defined>(ctx.config.entry);
 304     if (entry) {
 305       Chunk *chunk = entry->getChunk();
 306       entrySecIndex = chunk->getOutputSectionIdx();
 307       entryAddress =
 308           entry->getRVA() - ctx.getOutputSection(chunk)->header.VirtualAddress;
 309     }
 310   }
 311   os << " entry point at         ";
 312   os << format("%04x:%08llx", entrySecIndex, entryAddress);
 313   os << "\n";
 314
 315   // Print out the static symbols
 316   os << "\n";
 317   os << " Static symbols\n";
 318   os << "\n";
 319   for (Defined *sym : staticSyms)
 320     os << staticSymStr[sym] << '\n';
 321
 322   // Print out the exported functions
 323   if (ctx.config.mapInfo) {
 324     os << "\n";
 325     os << " Exports\n";
 326     os << "\n";
 327     os << "  ordinal    name\n\n";
 328     for (Export &e : ctx.config.exports) {
 329       os << format("  %7d", e.ordinal) << "    " << e.name << "\n";
 330       if (!e.extName.empty() && e.extName != e.name)
 331         os << "               exported name: " << e.extName << "\n";
 332     }
 333   }
 334
 335   t4.stop();
 336   t1.stop();
 337 }