llvm-project

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//===- MapFile.cpp --------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the /map option in the same format as link.exe
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// (based on observations)
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//
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// Header (program name, timestamp info, preferred load address)
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//
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// Section list (Start = Section index:Base address):
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// Start         Length     Name                   Class
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// 0001:00001000 00000015H .text                   CODE
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//
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// Symbols list:
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// Address        Publics by Value    Rva + Base          Lib:Object
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// 0001:00001000  main                 0000000140001000    main.obj
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// 0001:00001300  ?__scrt_common_main@@YAHXZ  0000000140001300 libcmt:exe_main.obj
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//
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// entry point at        0001:00000360
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//
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// Static symbols
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//
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// 0000:00000000  __guard_fids__       0000000140000000     libcmt : exe_main.obj
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//===----------------------------------------------------------------------===//
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#include "MapFile.h"
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#include "COFFLinkerContext.h"
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#include "SymbolTable.h"
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#include "Symbols.h"
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#include "Writer.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Timer.h"
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#include "llvm/Support/Parallel.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/TimeProfiler.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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using namespace llvm::object;
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using namespace lld;
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using namespace lld::coff;
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// Print out the first two columns of a line.
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static void writeHeader(raw_ostream &os, uint32_t sec, uint64_t addr) {
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  os << format(" %04x:%08llx", sec, addr);
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}
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// Write the time stamp with the format used by link.exe
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// It seems identical to strftime with "%c" on msvc build, but we need a
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// locale-agnostic version.
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static void writeFormattedTimestamp(raw_ostream &os, time_t tds) {
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  constexpr const char *const days[7] = {"Sun", "Mon", "Tue", "Wed",
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                                         "Thu", "Fri", "Sat"};
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  constexpr const char *const months[12] = {"Jan", "Feb", "Mar", "Apr",
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                                            "May", "Jun", "Jul", "Aug",
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                                            "Sep", "Oct", "Nov", "Dec"};
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  tm *time = localtime(&tds);
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  os << format("%s %s %2d %02d:%02d:%02d %d", days[time->tm_wday],
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               months[time->tm_mon], time->tm_mday, time->tm_hour, time->tm_min,
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               time->tm_sec, time->tm_year + 1900);
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}
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static void sortUniqueSymbols(std::vector<Defined *> &syms,
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                              uint64_t imageBase) {
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  // Build helper vector
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  using SortEntry = std::pair<Defined *, size_t>;
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  std::vector<SortEntry> v;
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  v.resize(syms.size());
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  for (size_t i = 0, e = syms.size(); i < e; ++i)
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    v[i] = SortEntry(syms[i], i);
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  // Remove duplicate symbol pointers
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  parallelSort(v, std::less<SortEntry>());
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  auto end = std::unique(v.begin(), v.end(),
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                         [](const SortEntry &a, const SortEntry &b) {
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                           return a.first == b.first;
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                         });
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  v.erase(end, v.end());
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  // Sort by RVA then original order
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  parallelSort(v, [imageBase](const SortEntry &a, const SortEntry &b) {
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    // Add config.imageBase to avoid comparing "negative" RVAs.
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    // This can happen with symbols of Absolute kind
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    uint64_t rvaa = imageBase + a.first->getRVA();
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    uint64_t rvab = imageBase + b.first->getRVA();
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    return rvaa < rvab || (rvaa == rvab && a.second < b.second);
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  });
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  syms.resize(v.size());
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  for (size_t i = 0, e = v.size(); i < e; ++i)
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    syms[i] = v[i].first;
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}
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// Returns the lists of all symbols that we want to print out.
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static void getSymbols(const COFFLinkerContext &ctx,
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                       std::vector<Defined *> &syms,
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                       std::vector<Defined *> &staticSyms) {
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  for (ObjFile *file : ctx.objFileInstances)
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    for (Symbol *b : file->getSymbols()) {
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      if (!b || !b->isLive())
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        continue;
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      if (auto *sym = dyn_cast<DefinedCOFF>(b)) {
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        COFFSymbolRef symRef = sym->getCOFFSymbol();
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        if (!symRef.isSectionDefinition() &&
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            symRef.getStorageClass() != COFF::IMAGE_SYM_CLASS_LABEL) {
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          if (symRef.getStorageClass() == COFF::IMAGE_SYM_CLASS_STATIC)
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            staticSyms.push_back(sym);
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          else
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            syms.push_back(sym);
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        }
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      } else if (auto *sym = dyn_cast<Defined>(b)) {
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        syms.push_back(sym);
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      }
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    }
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  for (ImportFile *file : ctx.importFileInstances) {
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    if (!file->live)
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      continue;
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    if (!file->thunkSym)
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      continue;
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    if (!file->thunkLive)
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      continue;
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    if (auto *thunkSym = dyn_cast<Defined>(file->thunkSym))
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      syms.push_back(thunkSym);
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    if (auto *impSym = dyn_cast_or_null<Defined>(file->impSym))
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      syms.push_back(impSym);
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  }
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  sortUniqueSymbols(syms, ctx.config.imageBase);
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  sortUniqueSymbols(staticSyms, ctx.config.imageBase);
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}
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// Construct a map from symbols to their stringified representations.
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static DenseMap<Defined *, std::string>
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getSymbolStrings(const COFFLinkerContext &ctx, ArrayRef<Defined *> syms) {
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  std::vector<std::string> str(syms.size());
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  parallelFor((size_t)0, syms.size(), [&](size_t i) {
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    raw_string_ostream os(str[i]);
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    Defined *sym = syms[i];
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    uint16_t sectionIdx = 0;
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    uint64_t address = 0;
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    SmallString<128> fileDescr;
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    if (auto *absSym = dyn_cast<DefinedAbsolute>(sym)) {
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      address = absSym->getVA();
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      fileDescr = "<absolute>";
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    } else if (isa<DefinedSynthetic>(sym)) {
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      fileDescr = "<linker-defined>";
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    } else if (isa<DefinedCommon>(sym)) {
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      fileDescr = "<common>";
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    } else if (Chunk *chunk = sym->getChunk()) {
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      address = sym->getRVA();
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      if (OutputSection *sec = ctx.getOutputSection(chunk))
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        address -= sec->header.VirtualAddress;
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      sectionIdx = chunk->getOutputSectionIdx();
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      InputFile *file;
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      if (auto *impSym = dyn_cast<DefinedImportData>(sym))
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        file = impSym->file;
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      else if (auto *thunkSym = dyn_cast<DefinedImportThunk>(sym))
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        file = thunkSym->wrappedSym->file;
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      else
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        file = sym->getFile();
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      if (file) {
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        if (!file->parentName.empty()) {
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          fileDescr = sys::path::filename(file->parentName);
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          sys::path::replace_extension(fileDescr, "");
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          fileDescr += ":";
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        }
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        fileDescr += sys::path::filename(file->getName());
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      }
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    }
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    writeHeader(os, sectionIdx, address);
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    os << "       ";
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    os << left_justify(sym->getName(), 26);
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    os << " ";
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    os << format_hex_no_prefix((ctx.config.imageBase + sym->getRVA()), 16);
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    if (!fileDescr.empty()) {
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      os << "     "; // FIXME : Handle "f" and "i" flags sometimes generated
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                     // by link.exe in those spaces
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      os << fileDescr;
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    }
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  });
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  DenseMap<Defined *, std::string> ret;
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  for (size_t i = 0, e = syms.size(); i < e; ++i)
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    ret[syms[i]] = std::move(str[i]);
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  return ret;
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}
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void lld::coff::writeMapFile(COFFLinkerContext &ctx) {
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  if (ctx.config.mapFile.empty())
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    return;
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  llvm::TimeTraceScope timeScope("Map file");
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  std::error_code ec;
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  raw_fd_ostream os(ctx.config.mapFile, ec, sys::fs::OF_None);
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  if (ec)
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    fatal("cannot open " + ctx.config.mapFile + ": " + ec.message());
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  ScopedTimer t1(ctx.totalMapTimer);
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  // Collect symbol info that we want to print out.
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  ScopedTimer t2(ctx.symbolGatherTimer);
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  std::vector<Defined *> syms;
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  std::vector<Defined *> staticSyms;
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  getSymbols(ctx, syms, staticSyms);
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  t2.stop();
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  ScopedTimer t3(ctx.symbolStringsTimer);
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  DenseMap<Defined *, std::string> symStr = getSymbolStrings(ctx, syms);
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  DenseMap<Defined *, std::string> staticSymStr =
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      getSymbolStrings(ctx, staticSyms);
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  t3.stop();
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  ScopedTimer t4(ctx.writeTimer);
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  SmallString<128> AppName = sys::path::filename(ctx.config.outputFile);
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  sys::path::replace_extension(AppName, "");
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  // Print out the file header
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  os << " " << AppName << "\n";
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  os << "\n";
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  os << " Timestamp is " << format_hex_no_prefix(ctx.config.timestamp, 8)
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     << " (";
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  if (ctx.config.repro) {
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    os << "Repro mode";
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  } else {
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    writeFormattedTimestamp(os, ctx.config.timestamp);
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  }
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  os << ")\n";
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  os << "\n";
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  os << " Preferred load address is "
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     << format_hex_no_prefix(ctx.config.imageBase, 16) << "\n";
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  os << "\n";
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  // Print out section table.
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  os << " Start         Length     Name                   Class\n";
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  for (OutputSection *sec : ctx.outputSections) {
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    // Merge display of chunks with same sectionName
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    std::vector<std::pair<SectionChunk *, SectionChunk *>> ChunkRanges;
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    for (Chunk *c : sec->chunks) {
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      auto *sc = dyn_cast<SectionChunk>(c);
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      if (!sc)
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        continue;
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      if (ChunkRanges.empty() ||
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          c->getSectionName() != ChunkRanges.back().first->getSectionName()) {
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        ChunkRanges.emplace_back(sc, sc);
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      } else {
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        ChunkRanges.back().second = sc;
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      }
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    }
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    const bool isCodeSection =
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        (sec->header.Characteristics & COFF::IMAGE_SCN_CNT_CODE) &&
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        (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_READ) &&
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        (sec->header.Characteristics & COFF::IMAGE_SCN_MEM_EXECUTE);
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    StringRef SectionClass = (isCodeSection ? "CODE" : "DATA");
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    for (auto &cr : ChunkRanges) {
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      size_t size =
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          cr.second->getRVA() + cr.second->getSize() - cr.first->getRVA();
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      auto address = cr.first->getRVA() - sec->header.VirtualAddress;
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      writeHeader(os, sec->sectionIndex, address);
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      os << " " << format_hex_no_prefix(size, 8) << "H";
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      os << " " << left_justify(cr.first->getSectionName(), 23);
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      os << " " << SectionClass;
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      os << '\n';
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    }
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  }
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  // Print out the symbols table (without static symbols)
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  os << "\n";
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  os << "  Address         Publics by Value              Rva+Base"
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        "               Lib:Object\n";
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  os << "\n";
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  for (Defined *sym : syms)
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    os << symStr[sym] << '\n';
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  // Print out the entry point.
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  os << "\n";
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  uint16_t entrySecIndex = 0;
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  uint64_t entryAddress = 0;
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  if (!ctx.config.noEntry) {
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    Defined *entry = dyn_cast_or_null<Defined>(ctx.config.entry);
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    if (entry) {
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      Chunk *chunk = entry->getChunk();
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      entrySecIndex = chunk->getOutputSectionIdx();
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      entryAddress =
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          entry->getRVA() - ctx.getOutputSection(chunk)->header.VirtualAddress;
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    }
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  }
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  os << " entry point at         ";
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  os << format("%04x:%08llx", entrySecIndex, entryAddress);
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  os << "\n";
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  // Print out the static symbols
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  os << "\n";
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  os << " Static symbols\n";
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  os << "\n";
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  for (Defined *sym : staticSyms)
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    os << staticSymStr[sym] << '\n';
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  // Print out the exported functions
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  if (ctx.config.mapInfo) {
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    os << "\n";
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    os << " Exports\n";
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    os << "\n";
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    os << "  ordinal    name\n\n";
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    for (Export &e : ctx.config.exports) {
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      os << format("  %7d", e.ordinal) << "    " << e.name << "\n";
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      if (!e.extName.empty() && e.extName != e.name)
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        os << "               exported name: " << e.extName << "\n";
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    }
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  }
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  t4.stop();
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  t1.stop();
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}
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