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->impSym)
 126       syms.push_back(file->impSym);
 127     if (file->thunkSym && file->thunkSym->isLive())
 128       syms.push_back(file->thunkSym);
 129     if (file->auxThunkSym && file->auxThunkSym->isLive())
 130       syms.push_back(file->auxThunkSym);
 131     if (file->impchkThunk)
 132       syms.push_back(file->impchkThunk->sym);
 133     if (file->impECSym)
 134       syms.push_back(file->impECSym);
 135     if (file->auxImpCopySym)
 136       syms.push_back(file->auxImpCopySym);
 137   }
 138
 139   sortUniqueSymbols(syms, ctx.config.imageBase);
 140   sortUniqueSymbols(staticSyms, ctx.config.imageBase);
 141 }
 142
 143 // Construct a map from symbols to their stringified representations.
 144 static DenseMap<Defined *, std::string>
 145 getSymbolStrings(const COFFLinkerContext &ctx, ArrayRef<Defined *> syms) {
 146   std::vector<std::string> str(syms.size());
 147   parallelFor((size_t)0, syms.size(), [&](size_t i) {
 148     raw_string_ostream os(str[i]);
 149     Defined *sym = syms[i];
 150
 151     uint16_t sectionIdx = 0;
 152     uint64_t address = 0;
 153     SmallString<128> fileDescr;
 154
 155     if (auto *absSym = dyn_cast<DefinedAbsolute>(sym)) {
 156       address = absSym->getVA();
 157       fileDescr = "<absolute>";
 158     } else if (isa<DefinedSynthetic>(sym)) {
 159       fileDescr = "<linker-defined>";
 160     } else if (isa<DefinedCommon>(sym)) {
 161       fileDescr = "<common>";
 162     } else if (Chunk *chunk = sym->getChunk()) {
 163       address = sym->getRVA();
 164       if (OutputSection *sec = ctx.getOutputSection(chunk))
 165         address -= sec->header.VirtualAddress;
 166
 167       sectionIdx = chunk->getOutputSectionIdx();
 168
 169       InputFile *file;
 170       if (auto *impSym = dyn_cast<DefinedImportData>(sym))
 171         file = impSym->file;
 172       else if (auto *thunkSym = dyn_cast<DefinedImportThunk>(sym))
 173         file = thunkSym->wrappedSym->file;
 174       else
 175         file = sym->getFile();
 176
 177       if (file) {
 178         if (!file->parentName.empty()) {
 179           fileDescr = sys::path::filename(file->parentName);
 180           sys::path::replace_extension(fileDescr, "");
 181           fileDescr += ":";
 182         }
 183         fileDescr += sys::path::filename(file->getName());
 184       }
 185     }
 186     writeHeader(os, sectionIdx, address);
 187     os << "       ";
 188     os << left_justify(sym->getName(), 26);
 189     os << " ";
 190     os << format_hex_no_prefix((ctx.config.imageBase + sym->getRVA()), 16);
 191     if (!fileDescr.empty()) {
 192       os << "     "; // FIXME : Handle "f" and "i" flags sometimes generated
 193                      // by link.exe in those spaces
 194       os << fileDescr;
 195     }
 196   });
 197
 198   DenseMap<Defined *, std::string> ret;
 199   for (size_t i = 0, e = syms.size(); i < e; ++i)
 200     ret[syms[i]] = std::move(str[i]);
 201   return ret;
 202 }
 203
 204 void lld::coff::writeMapFile(COFFLinkerContext &ctx) {
 205   if (ctx.config.mapFile.empty())
 206     return;
 207
 208   llvm::TimeTraceScope timeScope("Map file");
 209   std::error_code ec;
 210   raw_fd_ostream os(ctx.config.mapFile, ec, sys::fs::OF_None);
 211   if (ec)
 212     fatal("cannot open " + ctx.config.mapFile + ": " + ec.message());
 213
 214   ScopedTimer t1(ctx.totalMapTimer);
 215
 216   // Collect symbol info that we want to print out.
 217   ScopedTimer t2(ctx.symbolGatherTimer);
 218   std::vector<Defined *> syms;
 219   std::vector<Defined *> staticSyms;
 220   getSymbols(ctx, syms, staticSyms);
 221   t2.stop();
 222
 223   ScopedTimer t3(ctx.symbolStringsTimer);
 224   DenseMap<Defined *, std::string> symStr = getSymbolStrings(ctx, syms);
 225   DenseMap<Defined *, std::string> staticSymStr =
 226       getSymbolStrings(ctx, staticSyms);
 227   t3.stop();
 228
 229   ScopedTimer t4(ctx.writeTimer);
 230   SmallString<128> AppName = sys::path::filename(ctx.config.outputFile);
 231   sys::path::replace_extension(AppName, "");
 232
 233   // Print out the file header
 234   os << " " << AppName << "\n";
 235   os << "\n";
 236
 237   os << " Timestamp is " << format_hex_no_prefix(ctx.config.timestamp, 8)
 238      << " (";
 239   if (ctx.config.repro) {
 240     os << "Repro mode";
 241   } else {
 242     writeFormattedTimestamp(os, ctx.config.timestamp);
 243   }
 244   os << ")\n";
 245
 246   os << "\n";
 247   os << " Preferred load address is "
 248      << format_hex_no_prefix(ctx.config.imageBase, 16) << "\n";
 249   os << "\n";
 250
 251   // Print out section table.
 252   os << " Start         Length     Name                   Class\n";
 253
 254   for (OutputSection *sec : ctx.outputSections) {
 255     // Merge display of chunks with same sectionName
 256     std::vector<std::pair<SectionChunk *, SectionChunk *>> ChunkRanges;
 257     for (Chunk *c : sec->chunks) {
 258       auto *sc = dyn_cast<SectionChunk>(c);
 259       if (!sc)
 260         continue;
 261
 262       if (ChunkRanges.empty() ||
 263           c->getSectionName() != ChunkRanges.back().first->getSectionName()) {
 264         ChunkRanges.emplace_back(sc, sc);
 265       } else {
 266         ChunkRanges.back().second = sc;
 267       }
 268     }
 269
 270     const bool isCodeSection =
 271         (sec->header.Characteristics & COFF::IMAGE_SCN_CNT_CODE) &&
 272         (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_READ) &&
 273         (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_EXECUTE);
 274     StringRef SectionClass = (isCodeSection ? "CODE" : "DATA");
 275
 276     for (auto &cr : ChunkRanges) {
 277       size_t size =
 278           cr.second->getRVA() + cr.second->getSize() - cr.first->getRVA();
 279
 280       auto address = cr.first->getRVA() - sec->header.VirtualAddress;
 281       writeHeader(os, sec->sectionIndex, address);
 282       os << " " << format_hex_no_prefix(size, 8) << "H";
 283       os << " " << left_justify(cr.first->getSectionName(), 23);
 284       os << " " << SectionClass;
 285       os << '\n';
 286     }
 287   }
 288
 289   // Print out the symbols table (without static symbols)
 290   os << "\n";
 291   os << "  Address         Publics by Value              Rva+Base"
 292         "               Lib:Object\n";
 293   os << "\n";
 294   for (Defined *sym : syms)
 295     os << symStr[sym] << '\n';
 296
 297   // Print out the entry point.
 298   os << "\n";
 299
 300   uint16_t entrySecIndex = 0;
 301   uint64_t entryAddress = 0;
 302
 303   if (!ctx.config.noEntry) {
 304     Defined *entry = dyn_cast_or_null<Defined>(ctx.config.entry);
 305     if (entry) {
 306       Chunk *chunk = entry->getChunk();
 307       entrySecIndex = chunk->getOutputSectionIdx();
 308       entryAddress =
 309           entry->getRVA() - ctx.getOutputSection(chunk)->header.VirtualAddress;
 310     }
 311   }
 312   os << " entry point at         ";
 313   os << format("%04x:%08llx", entrySecIndex, entryAddress);
 314   os << "\n";
 315
 316   // Print out the static symbols
 317   os << "\n";
 318   os << " Static symbols\n";
 319   os << "\n";
 320   for (Defined *sym : staticSyms)
 321     os << staticSymStr[sym] << '\n';
 322
 323   // Print out the exported functions
 324   if (ctx.config.mapInfo) {
 325     os << "\n";
 326     os << " Exports\n";
 327     os << "\n";
 328     os << "  ordinal    name\n\n";
 329     for (Export &e : ctx.config.exports) {
 330       os << format("  %7d", e.ordinal) << "    " << e.name << "\n";
 331       if (!e.extName.empty() && e.extName != e.name)
 332         os << "               exported name: " << e.extName << "\n";
 333     }
 334   }
 335
 336   t4.stop();
 337   t1.stop();
 338 }