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 ctx.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/Option/Option.h"
  20 #include "llvm/Support/CommandLine.h"
  21 #include "llvm/Support/FileSystem.h"
  22 #include "llvm/Support/Path.h"
  23 #include "llvm/Support/TimeProfiler.h"
  24 #include "llvm/TargetParser/Host.h"
  25 #include "llvm/TargetParser/Triple.h"
  26 #include <optional>
  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)                                                    \
  38   static constexpr StringLiteral NAME##_init[] = VALUE;                        \
  39   static constexpr ArrayRef<StringLiteral> NAME(NAME##_init,                   \
  40                                                 std::size(NAME##_init) - 1);
  41 #include "Options.inc"
  42 #undef PREFIX
  43
  44 // Create table mapping all options defined in Options.td
  45 static constexpr opt::OptTable::Info optInfo[] = {
  46 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
  47 #include "Options.inc"
  48 #undef OPTION
  49 };
  50
  51 ELFOptTable::ELFOptTable() : GenericOptTable(optInfo) {}
  52
  53 // Set color diagnostics according to --color-diagnostics={auto,always,never}
  54 // or --no-color-diagnostics flags.
  55 static void handleColorDiagnostics(opt::InputArgList &args) {
  56   auto *arg = args.getLastArg(OPT_color_diagnostics);
  57   if (!arg)
  58     return;
  59   StringRef s = arg->getValue();
  60   if (s == "always")
  61     lld::errs().enable_colors(true);
  62   else if (s == "never")
  63     lld::errs().enable_colors(false);
  64   else if (s != "auto")
  65     error("unknown option: --color-diagnostics=" + s);
  66 }
  67
  68 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &args) {
  69   if (auto *arg = args.getLastArg(OPT_rsp_quoting)) {
  70     StringRef s = arg->getValue();
  71     if (s != "windows" && s != "posix")
  72       error("invalid response file quoting: " + s);
  73     if (s == "windows")
  74       return cl::TokenizeWindowsCommandLine;
  75     return cl::TokenizeGNUCommandLine;
  76   }
  77   if (Triple(sys::getProcessTriple()).isOSWindows())
  78     return cl::TokenizeWindowsCommandLine;
  79   return cl::TokenizeGNUCommandLine;
  80 }
  81
  82 // Gold LTO plugin takes a `--plugin-opt foo=bar` option as an alias for
  83 // `--plugin-opt=foo=bar`. We want to handle `--plugin-opt=foo=` as an
  84 // option name and `bar` as a value. Unfortunately, OptParser cannot
  85 // handle an option with a space in it.
  86 //
  87 // In this function, we concatenate command line arguments so that
  88 // `--plugin-opt <foo>` is converted to `--plugin-opt=<foo>`. This is a
  89 // bit hacky, but looks like it is still better than handling --plugin-opt
  90 // options by hand.
  91 static void concatLTOPluginOptions(SmallVectorImpl<const char *> &args) {
  92   SmallVector<const char *, 256> v;
  93   for (size_t i = 0, e = args.size(); i != e; ++i) {
  94     StringRef s = args[i];
  95     if ((s == "-plugin-opt" || s == "--plugin-opt") && i + 1 != e) {
  96       v.push_back(saver().save(s + "=" + args[i + 1]).data());
  97       ++i;
  98     } else {
  99       v.push_back(args[i]);
 100     }
 101   }
 102   args = std::move(v);
 103 }
 104
 105 // Parses a given list of options.
 106 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> argv) {
 107   // Make InputArgList from string vectors.
 108   unsigned missingIndex;
 109   unsigned missingCount;
 110   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
 111
 112   // We need to get the quoting style for response files before parsing all
 113   // options so we parse here before and ignore all the options but
 114   // --rsp-quoting.
 115   opt::InputArgList args = this->ParseArgs(vec, missingIndex, missingCount);
 116
 117   // Expand response files (arguments in the form of @<filename>)
 118   // and then parse the argument again.
 119   cl::ExpandResponseFiles(saver(), getQuotingStyle(args), vec);
 120   concatLTOPluginOptions(vec);
 121   args = this->ParseArgs(vec, missingIndex, missingCount);
 122
 123   handleColorDiagnostics(args);
 124   if (missingCount)
 125     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
 126
 127   for (opt::Arg *arg : args.filtered(OPT_UNKNOWN)) {
 128     std::string nearest;
 129     if (findNearest(arg->getAsString(args), nearest) > 1)
 130       error("unknown argument '" + arg->getAsString(args) + "'");
 131     else
 132       error("unknown argument '" + arg->getAsString(args) +
 133             "', did you mean '" + nearest + "'");
 134   }
 135   return args;
 136 }
 137
 138 void elf::printHelp() {
 139   ELFOptTable().printHelp(
 140       lld::outs(), (config->progName + " [options] file...").str().c_str(),
 141       "lld", false /*ShowHidden*/, true /*ShowAllAliases*/);
 142   lld::outs() << "\n";
 143
 144   // Scripts generated by Libtool versions up to 2021-10 expect /: supported
 145   // targets:.* elf/ in a message for the --help option. If it doesn't match,
 146   // the scripts assume that the linker doesn't support very basic features
 147   // such as shared libraries. Therefore, we need to print out at least "elf".
 148   lld::outs() << config->progName << ": supported targets: elf\n";
 149 }
 150
 151 static std::string rewritePath(StringRef s) {
 152   if (fs::exists(s))
 153     return relativeToRoot(s);
 154   return std::string(s);
 155 }
 156
 157 // Reconstructs command line arguments so that so that you can re-run
 158 // the same command with the same inputs. This is for --reproduce.
 159 std::string elf::createResponseFile(const opt::InputArgList &args) {
 160   SmallString<0> data;
 161   raw_svector_ostream os(data);
 162   os << "--chroot .\n";
 163
 164   // Copy the command line to the output while rewriting paths.
 165   for (auto *arg : args) {
 166     switch (arg->getOption().getID()) {
 167     case OPT_reproduce:
 168       break;
 169     case OPT_INPUT:
 170       os << quote(rewritePath(arg->getValue())) << "\n";
 171       break;
 172     case OPT_o:
 173     case OPT_Map:
 174     case OPT_print_archive_stats:
 175     case OPT_why_extract:
 176       // If an output path contains directories, "lld @response.txt" will
 177       // likely fail because the archive we are creating doesn't contain empty
 178       // directories for the output path (-o doesn't create directories).
 179       // Strip directories to prevent the issue.
 180       os << arg->getSpelling();
 181       if (arg->getOption().getRenderStyle() == opt::Option::RenderSeparateStyle)
 182         os << ' ';
 183       os << quote(path::filename(arg->getValue())) << '\n';
 184       break;
 185     case OPT_lto_sample_profile:
 186       os << arg->getSpelling() << quote(rewritePath(arg->getValue())) << "\n";
 187       break;
 188     case OPT_call_graph_ordering_file:
 189     case OPT_default_script:
 190     case OPT_dynamic_list:
 191     case OPT_export_dynamic_symbol_list:
 192     case OPT_just_symbols:
 193     case OPT_library_path:
 194     case OPT_remap_inputs_file:
 195     case OPT_retain_symbols_file:
 196     case OPT_rpath:
 197     case OPT_script:
 198     case OPT_symbol_ordering_file:
 199     case OPT_sysroot:
 200     case OPT_version_script:
 201       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
 202          << "\n";
 203       break;
 204     default:
 205       os << toString(*arg) << "\n";
 206     }
 207   }
 208   return std::string(data);
 209 }
 210
 211 // Find a file by concatenating given paths. If a resulting path
 212 // starts with "=", the character is replaced with a --sysroot value.
 213 static std::optional<std::string> findFile(StringRef path1,
 214                                            const Twine &path2) {
 215   SmallString<128> s;
 216   if (path1.starts_with("="))
 217     path::append(s, config->sysroot, path1.substr(1), path2);
 218   else
 219     path::append(s, path1, path2);
 220
 221   if (fs::exists(s))
 222     return std::string(s);
 223   return std::nullopt;
 224 }
 225
 226 std::optional<std::string> elf::findFromSearchPaths(StringRef path) {
 227   for (StringRef dir : config->searchPaths)
 228     if (std::optional<std::string> s = findFile(dir, path))
 229       return s;
 230   return std::nullopt;
 231 }
 232
 233 // This is for -l<basename>. We'll look for lib<basename>.so or lib<basename>.a from
 234 // search paths.
 235 std::optional<std::string> elf::searchLibraryBaseName(StringRef name) {
 236   for (StringRef dir : config->searchPaths) {
 237     if (!config->isStatic)
 238       if (std::optional<std::string> s = findFile(dir, "lib" + name + ".so"))
 239         return s;
 240     if (std::optional<std::string> s = findFile(dir, "lib" + name + ".a"))
 241       return s;
 242   }
 243   return std::nullopt;
 244 }
 245
 246 // This is for -l<namespec>.
 247 std::optional<std::string> elf::searchLibrary(StringRef name) {
 248   llvm::TimeTraceScope timeScope("Locate library", name);
 249   if (name.starts_with(":"))
 250     return findFromSearchPaths(name.substr(1));
 251   return searchLibraryBaseName(name);
 252 }
 253
 254 // If a linker/version script doesn't exist in the current directory, we also
 255 // look for the script in the '-L' search paths. This matches the behaviour of
 256 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
 257 std::optional<std::string> elf::searchScript(StringRef name) {
 258   if (fs::exists(name))
 259     return name.str();
 260   return findFromSearchPaths(name);
 261 }