lld/ELF/DriverUtils.cpp

   1 //===- DriverUtils.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 contains utility functions for the driver. Because there
  10 // are so many small functions, we created this separate file to make
  11 // Driver.cpp less cluttered.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "Config.h"
  16 #include "Driver.h"
  17 #include "lld/Common/CommonLinkerContext.h"
  18 #include "lld/Common/Reproduce.h"
  19 #include "llvm/ADT/Optional.h"
  20 #include "llvm/ADT/Triple.h"
  21 #include "llvm/Option/Option.h"
  22 #include "llvm/Support/CommandLine.h"
  23 #include "llvm/Support/FileSystem.h"
  24 #include "llvm/Support/Host.h"
  25 #include "llvm/Support/Path.h"
  26 #include "llvm/Support/TimeProfiler.h"
  27
  28 using namespace llvm;
  29 using namespace llvm::sys;
  30 using namespace llvm::opt;
  31 using namespace lld;
  32 using namespace lld::elf;
  33
  34 // Create OptTable
  35
  36 // Create prefix string literals used in Options.td
  37 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
  38 #include "Options.inc"
  39 #undef PREFIX
  40
  41 // Create table mapping all options defined in Options.td
  42 static const opt::OptTable::Info optInfo[] = {
  43 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
  44   {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
  45    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
  46 #include "Options.inc"
  47 #undef OPTION
  48 };
  49
  50 ELFOptTable::ELFOptTable() : OptTable(optInfo) {}
  51
  52 // Set color diagnostics according to --color-diagnostics={auto,always,never}
  53 // or --no-color-diagnostics flags.
  54 static void handleColorDiagnostics(opt::InputArgList &args) {
  55   auto *arg = args.getLastArg(OPT_color_diagnostics);
  56   if (!arg)
  57     return;
  58   StringRef s = arg->getValue();
  59   if (s == "always")
  60     lld::errs().enable_colors(true);
  61   else if (s == "never")
  62     lld::errs().enable_colors(false);
  63   else if (s != "auto")
  64     error("unknown option: --color-diagnostics=" + s);
  65 }
  66
  67 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &args) {
  68   if (auto *arg = args.getLastArg(OPT_rsp_quoting)) {
  69     StringRef s = arg->getValue();
  70     if (s != "windows" && s != "posix")
  71       error("invalid response file quoting: " + s);
  72     if (s == "windows")
  73       return cl::TokenizeWindowsCommandLine;
  74     return cl::TokenizeGNUCommandLine;
  75   }
  76   if (Triple(sys::getProcessTriple()).isOSWindows())
  77     return cl::TokenizeWindowsCommandLine;
  78   return cl::TokenizeGNUCommandLine;
  79 }
  80
  81 // Gold LTO plugin takes a `--plugin-opt foo=bar` option as an alias for
  82 // `--plugin-opt=foo=bar`. We want to handle `--plugin-opt=foo=` as an
  83 // option name and `bar` as a value. Unfortunately, OptParser cannot
  84 // handle an option with a space in it.
  85 //
  86 // In this function, we concatenate command line arguments so that
  87 // `--plugin-opt <foo>` is converted to `--plugin-opt=<foo>`. This is a
  88 // bit hacky, but looks like it is still better than handling --plugin-opt
  89 // options by hand.
  90 static void concatLTOPluginOptions(SmallVectorImpl<const char *> &args) {
  91   SmallVector<const char *, 256> v;
  92   for (size_t i = 0, e = args.size(); i != e; ++i) {
  93     StringRef s = args[i];
  94     if ((s == "-plugin-opt" || s == "--plugin-opt") && i + 1 != e) {
  95       v.push_back(saver().save(s + "=" + args[i + 1]).data());
  96       ++i;
  97     } else {
  98       v.push_back(args[i]);
  99     }
 100   }
 101   args = std::move(v);
 102 }
 103
 104 // Parses a given list of options.
 105 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> argv) {
 106   // Make InputArgList from string vectors.
 107   unsigned missingIndex;
 108   unsigned missingCount;
 109   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
 110
 111   // We need to get the quoting style for response files before parsing all
 112   // options so we parse here before and ignore all the options but
 113   // --rsp-quoting.
 114   opt::InputArgList args = this->ParseArgs(vec, missingIndex, missingCount);
 115
 116   // Expand response files (arguments in the form of @<filename>)
 117   // and then parse the argument again.
 118   cl::ExpandResponseFiles(saver(), getQuotingStyle(args), vec);
 119   concatLTOPluginOptions(vec);
 120   args = this->ParseArgs(vec, missingIndex, missingCount);
 121
 122   handleColorDiagnostics(args);
 123   if (missingCount)
 124     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
 125
 126   for (opt::Arg *arg : args.filtered(OPT_UNKNOWN)) {
 127     std::string nearest;
 128     if (findNearest(arg->getAsString(args), nearest) > 1)
 129       error("unknown argument '" + arg->getAsString(args) + "'");
 130     else
 131       error("unknown argument '" + arg->getAsString(args) +
 132             "', did you mean '" + nearest + "'");
 133   }
 134   return args;
 135 }
 136
 137 void elf::printHelp() {
 138   ELFOptTable().printHelp(
 139       lld::outs(), (config->progName + " [options] file...").str().c_str(),
 140       "lld", false /*ShowHidden*/, true /*ShowAllAliases*/);
 141   lld::outs() << "\n";
 142
 143   // Scripts generated by Libtool versions up to 2021-10 expect /: supported
 144   // targets:.* elf/ in a message for the --help option. If it doesn't match,
 145   // the scripts assume that the linker doesn't support very basic features
 146   // such as shared libraries. Therefore, we need to print out at least "elf".
 147   lld::outs() << config->progName << ": supported targets: elf\n";
 148 }
 149
 150 static std::string rewritePath(StringRef s) {
 151   if (fs::exists(s))
 152     return relativeToRoot(s);
 153   return std::string(s);
 154 }
 155
 156 // Reconstructs command line arguments so that so that you can re-run
 157 // the same command with the same inputs. This is for --reproduce.
 158 std::string elf::createResponseFile(const opt::InputArgList &args) {
 159   SmallString<0> data;
 160   raw_svector_ostream os(data);
 161   os << "--chroot .\n";
 162
 163   // Copy the command line to the output while rewriting paths.
 164   for (auto *arg : args) {
 165     switch (arg->getOption().getID()) {
 166     case OPT_reproduce:
 167       break;
 168     case OPT_INPUT:
 169       os << quote(rewritePath(arg->getValue())) << "\n";
 170       break;
 171     case OPT_o:
 172     case OPT_Map:
 173     case OPT_print_archive_stats:
 174     case OPT_why_extract:
 175       // If an output path contains directories, "lld @response.txt" will
 176       // likely fail because the archive we are creating doesn't contain empty
 177       // directories for the output path (-o doesn't create directories).
 178       // Strip directories to prevent the issue.
 179       os << arg->getSpelling();
 180       if (arg->getOption().getRenderStyle() == opt::Option::RenderSeparateStyle)
 181         os << ' ';
 182       os << quote(path::filename(arg->getValue())) << '\n';
 183       break;
 184     case OPT_lto_sample_profile:
 185       os << arg->getSpelling() << quote(rewritePath(arg->getValue())) << "\n";
 186       break;
 187     case OPT_call_graph_ordering_file:
 188     case OPT_dynamic_list:
 189     case OPT_export_dynamic_symbol_list:
 190     case OPT_just_symbols:
 191     case OPT_library_path:
 192     case OPT_retain_symbols_file:
 193     case OPT_rpath:
 194     case OPT_script:
 195     case OPT_symbol_ordering_file:
 196     case OPT_sysroot:
 197     case OPT_version_script:
 198       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
 199          << "\n";
 200       break;
 201     default:
 202       os << toString(*arg) << "\n";
 203     }
 204   }
 205   return std::string(data.str());
 206 }
 207
 208 // Find a file by concatenating given paths. If a resulting path
 209 // starts with "=", the character is replaced with a --sysroot value.
 210 static Optional<std::string> findFile(StringRef path1, const Twine &path2) {
 211   SmallString<128> s;
 212   if (path1.startswith("="))
 213     path::append(s, config->sysroot, path1.substr(1), path2);
 214   else
 215     path::append(s, path1, path2);
 216
 217   if (fs::exists(s))
 218     return std::string(s);
 219   return None;
 220 }
 221
 222 Optional<std::string> elf::findFromSearchPaths(StringRef path) {
 223   for (StringRef dir : config->searchPaths)
 224     if (Optional<std::string> s = findFile(dir, path))
 225       return s;
 226   return None;
 227 }
 228
 229 // This is for -l<basename>. We'll look for lib<basename>.so or lib<basename>.a from
 230 // search paths.
 231 Optional<std::string> elf::searchLibraryBaseName(StringRef name) {
 232   for (StringRef dir : config->searchPaths) {
 233     if (!config->isStatic)
 234       if (Optional<std::string> s = findFile(dir, "lib" + name + ".so"))
 235         return s;
 236     if (Optional<std::string> s = findFile(dir, "lib" + name + ".a"))
 237       return s;
 238   }
 239   return None;
 240 }
 241
 242 // This is for -l<namespec>.
 243 Optional<std::string> elf::searchLibrary(StringRef name) {
 244   llvm::TimeTraceScope timeScope("Locate library", name);
 245   if (name.startswith(":"))
 246     return findFromSearchPaths(name.substr(1));
 247   return searchLibraryBaseName(name);
 248 }
 249
 250 // If a linker/version script doesn't exist in the current directory, we also
 251 // look for the script in the '-L' search paths. This matches the behaviour of
 252 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
 253 Optional<std::string> elf::searchScript(StringRef name) {
 254   if (fs::exists(name))
 255     return name.str();
 256   return findFromSearchPaths(name);
 257 }