xref: /freebsd/contrib/llvm-project/lld/MachO/DriverUtils.cpp (revision 56b17de1e8360fe131d425de20b5e75ff3ea897c)
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 #include "Config.h"
10 #include "Driver.h"
11 #include "InputFiles.h"
12 #include "ObjC.h"
13 #include "Target.h"
14 
15 #include "lld/Common/Args.h"
16 #include "lld/Common/CommonLinkerContext.h"
17 #include "lld/Common/Reproduce.h"
18 #include "llvm/ADT/CachedHashString.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/LTO/LTO.h"
21 #include "llvm/Option/Arg.h"
22 #include "llvm/Option/ArgList.h"
23 #include "llvm/Option/Option.h"
24 #include "llvm/Support/CommandLine.h"
25 #include "llvm/Support/FileSystem.h"
26 #include "llvm/Support/Path.h"
27 #include "llvm/TextAPI/InterfaceFile.h"
28 #include "llvm/TextAPI/TextAPIReader.h"
29 
30 using namespace llvm;
31 using namespace llvm::MachO;
32 using namespace llvm::opt;
33 using namespace llvm::sys;
34 using namespace lld;
35 using namespace lld::macho;
36 
37 // Create prefix string literals used in Options.td
38 #define PREFIX(NAME, VALUE)                                                    \
39   static constexpr StringLiteral NAME##_init[] = VALUE;                        \
40   static constexpr ArrayRef<StringLiteral> NAME(NAME##_init,                   \
41                                                 std::size(NAME##_init) - 1);
42 #include "Options.inc"
43 #undef PREFIX
44 
45 // Create table mapping all options defined in Options.td
46 static constexpr OptTable::Info optInfo[] = {
47 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS,         \
48                VISIBILITY, PARAM, HELPTEXT, HELPTEXTSFORVARIANTS, METAVAR,     \
49                VALUES)                                                         \
50   {PREFIX,                                                                     \
51    NAME,                                                                       \
52    HELPTEXT,                                                                   \
53    HELPTEXTSFORVARIANTS,                                                       \
54    METAVAR,                                                                    \
55    OPT_##ID,                                                                   \
56    opt::Option::KIND##Class,                                                   \
57    PARAM,                                                                      \
58    FLAGS,                                                                      \
59    VISIBILITY,                                                                 \
60    OPT_##GROUP,                                                                \
61    OPT_##ALIAS,                                                                \
62    ALIASARGS,                                                                  \
63    VALUES},
64 #include "Options.inc"
65 #undef OPTION
66 };
67 
68 MachOOptTable::MachOOptTable() : GenericOptTable(optInfo) {}
69 
70 // Set color diagnostics according to --color-diagnostics={auto,always,never}
71 // or --no-color-diagnostics flags.
72 static void handleColorDiagnostics(InputArgList &args) {
73   const Arg *arg =
74       args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
75                       OPT_no_color_diagnostics);
76   if (!arg)
77     return;
78   if (arg->getOption().getID() == OPT_color_diagnostics) {
79     lld::errs().enable_colors(true);
80   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
81     lld::errs().enable_colors(false);
82   } else {
83     StringRef s = arg->getValue();
84     if (s == "always")
85       lld::errs().enable_colors(true);
86     else if (s == "never")
87       lld::errs().enable_colors(false);
88     else if (s != "auto")
89       error("unknown option: --color-diagnostics=" + s);
90   }
91 }
92 
93 InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
94   // Make InputArgList from string vectors.
95   unsigned missingIndex;
96   unsigned missingCount;
97   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
98 
99   // Expand response files (arguments in the form of @<filename>)
100   // and then parse the argument again.
101   cl::ExpandResponseFiles(saver(), cl::TokenizeGNUCommandLine, vec);
102   InputArgList args = ParseArgs(vec, missingIndex, missingCount);
103 
104   // Handle -fatal_warnings early since it converts missing argument warnings
105   // to errors.
106   errorHandler().fatalWarnings = args.hasArg(OPT_fatal_warnings);
107   errorHandler().suppressWarnings = args.hasArg(OPT_w);
108 
109   if (missingCount)
110     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
111 
112   handleColorDiagnostics(args);
113 
114   for (const Arg *arg : args.filtered(OPT_UNKNOWN)) {
115     std::string nearest;
116     if (findNearest(arg->getAsString(args), nearest) > 1)
117       error("unknown argument '" + arg->getAsString(args) + "'");
118     else
119       error("unknown argument '" + arg->getAsString(args) +
120             "', did you mean '" + nearest + "'");
121   }
122   return args;
123 }
124 
125 void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
126   OptTable::printHelp(lld::outs(),
127                       (std::string(argv0) + " [options] file...").c_str(),
128                       "LLVM Linker", showHidden);
129   lld::outs() << "\n";
130 }
131 
132 static std::string rewritePath(StringRef s) {
133   if (fs::exists(s))
134     return relativeToRoot(s);
135   return std::string(s);
136 }
137 
138 static std::string rewriteInputPath(StringRef s) {
139   // Don't bother rewriting "absolute" paths that are actually under the
140   // syslibroot; simply rewriting the syslibroot is sufficient.
141   if (rerootPath(s) == s && fs::exists(s))
142     return relativeToRoot(s);
143   return std::string(s);
144 }
145 
146 // Reconstructs command line arguments so that so that you can re-run
147 // the same command with the same inputs. This is for --reproduce.
148 std::string macho::createResponseFile(const InputArgList &args) {
149   SmallString<0> data;
150   raw_svector_ostream os(data);
151 
152   // Copy the command line to the output while rewriting paths.
153   for (const Arg *arg : args) {
154     switch (arg->getOption().getID()) {
155     case OPT_reproduce:
156       break;
157     case OPT_INPUT:
158       os << quote(rewriteInputPath(arg->getValue())) << "\n";
159       break;
160     case OPT_o:
161       os << "-o " << quote(path::filename(arg->getValue())) << "\n";
162       break;
163     case OPT_filelist:
164       if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
165         for (StringRef path : args::getLines(*buffer))
166           os << quote(rewriteInputPath(path)) << "\n";
167       break;
168     case OPT_force_load:
169     case OPT_weak_library:
170     case OPT_load_hidden:
171       os << arg->getSpelling() << " "
172          << quote(rewriteInputPath(arg->getValue())) << "\n";
173       break;
174     case OPT_F:
175     case OPT_L:
176     case OPT_bundle_loader:
177     case OPT_exported_symbols_list:
178     case OPT_order_file:
179     case OPT_syslibroot:
180     case OPT_unexported_symbols_list:
181       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
182          << "\n";
183       break;
184     case OPT_sectcreate:
185       os << arg->getSpelling() << " " << quote(arg->getValue(0)) << " "
186          << quote(arg->getValue(1)) << " "
187          << quote(rewritePath(arg->getValue(2))) << "\n";
188       break;
189     default:
190       os << toString(*arg) << "\n";
191     }
192   }
193   return std::string(data);
194 }
195 
196 static void searchedDylib(const Twine &path, bool found) {
197   if (config->printDylibSearch)
198     message("searched " + path + (found ? ", found " : ", not found"));
199   if (!found)
200     depTracker->logFileNotFound(path);
201 }
202 
203 std::optional<StringRef> macho::resolveDylibPath(StringRef dylibPath) {
204   // TODO: if a tbd and dylib are both present, we should check to make sure
205   // they are consistent.
206   SmallString<261> tbdPath = dylibPath;
207   path::replace_extension(tbdPath, ".tbd");
208   bool tbdExists = fs::exists(tbdPath);
209   searchedDylib(tbdPath, tbdExists);
210   if (tbdExists)
211     return saver().save(tbdPath.str());
212 
213   bool dylibExists = fs::exists(dylibPath);
214   searchedDylib(dylibPath, dylibExists);
215   if (dylibExists)
216     return saver().save(dylibPath);
217   return {};
218 }
219 
220 // It's not uncommon to have multiple attempts to load a single dylib,
221 // especially if it's a commonly re-exported core library.
222 static DenseMap<CachedHashStringRef, DylibFile *> loadedDylibs;
223 
224 DylibFile *macho::loadDylib(MemoryBufferRef mbref, DylibFile *umbrella,
225                             bool isBundleLoader, bool explicitlyLinked) {
226   CachedHashStringRef path(mbref.getBufferIdentifier());
227   DylibFile *&file = loadedDylibs[path];
228   if (file) {
229     if (explicitlyLinked)
230       file->setExplicitlyLinked();
231     return file;
232   }
233 
234   DylibFile *newFile;
235   file_magic magic = identify_magic(mbref.getBuffer());
236   if (magic == file_magic::tapi_file) {
237     Expected<std::unique_ptr<InterfaceFile>> result = TextAPIReader::get(mbref);
238     if (!result) {
239       error("could not load TAPI file at " + mbref.getBufferIdentifier() +
240             ": " + toString(result.takeError()));
241       return nullptr;
242     }
243     file =
244         make<DylibFile>(**result, umbrella, isBundleLoader, explicitlyLinked);
245 
246     // parseReexports() can recursively call loadDylib(). That's fine since
247     // we wrote the DylibFile we just loaded to the loadDylib cache via the
248     // `file` reference. But the recursive load can grow loadDylibs, so the
249     // `file` reference might become invalid after parseReexports() -- so copy
250     // the pointer it refers to before continuing.
251     newFile = file;
252     if (newFile->exportingFile)
253       newFile->parseReexports(**result);
254   } else {
255     assert(magic == file_magic::macho_dynamically_linked_shared_lib ||
256            magic == file_magic::macho_dynamically_linked_shared_lib_stub ||
257            magic == file_magic::macho_executable ||
258            magic == file_magic::macho_bundle);
259     file = make<DylibFile>(mbref, umbrella, isBundleLoader, explicitlyLinked);
260 
261     // parseLoadCommands() can also recursively call loadDylib(). See comment
262     // in previous block for why this means we must copy `file` here.
263     newFile = file;
264     if (newFile->exportingFile)
265       newFile->parseLoadCommands(mbref);
266   }
267   return newFile;
268 }
269 
270 void macho::resetLoadedDylibs() { loadedDylibs.clear(); }
271 
272 std::optional<StringRef>
273 macho::findPathCombination(const Twine &name,
274                            const std::vector<StringRef> &roots,
275                            ArrayRef<StringRef> extensions) {
276   SmallString<261> base;
277   for (StringRef dir : roots) {
278     base = dir;
279     path::append(base, name);
280     for (StringRef ext : extensions) {
281       Twine location = base + ext;
282       bool exists = fs::exists(location);
283       searchedDylib(location, exists);
284       if (exists)
285         return saver().save(location.str());
286     }
287   }
288   return {};
289 }
290 
291 StringRef macho::rerootPath(StringRef path) {
292   if (!path::is_absolute(path, path::Style::posix) || path.ends_with(".o"))
293     return path;
294 
295   if (std::optional<StringRef> rerootedPath =
296           findPathCombination(path, config->systemLibraryRoots))
297     return *rerootedPath;
298 
299   return path;
300 }
301 
302 uint32_t macho::getModTime(StringRef path) {
303   if (config->zeroModTime)
304     return 0;
305 
306   fs::file_status stat;
307   if (!fs::status(path, stat))
308     if (fs::exists(stat))
309       return toTimeT(stat.getLastModificationTime());
310 
311   warn("failed to get modification time of " + path);
312   return 0;
313 }
314 
315 void macho::printArchiveMemberLoad(StringRef reason, const InputFile *f) {
316   if (config->printEachFile)
317     message(toString(f));
318   if (config->printWhyLoad)
319     message(reason + " forced load of " + toString(f));
320 }
321 
322 macho::DependencyTracker::DependencyTracker(StringRef path)
323     : path(path), active(!path.empty()) {
324   if (active && fs::exists(path) && !fs::can_write(path)) {
325     warn("Ignoring dependency_info option since specified path is not "
326          "writeable.");
327     active = false;
328   }
329 }
330 
331 void macho::DependencyTracker::write(StringRef version,
332                                      const SetVector<InputFile *> &inputs,
333                                      StringRef output) {
334   if (!active)
335     return;
336 
337   std::error_code ec;
338   raw_fd_ostream os(path, ec, fs::OF_None);
339   if (ec) {
340     warn("Error writing dependency info to file");
341     return;
342   }
343 
344   auto addDep = [&os](DepOpCode opcode, const StringRef &path) {
345     // XXX: Even though DepOpCode's underlying type is uint8_t,
346     // this cast is still needed because Clang older than 10.x has a bug,
347     // where it doesn't know to cast the enum to its underlying type.
348     // Hence `<< DepOpCode` is ambiguous to it.
349     os << static_cast<uint8_t>(opcode);
350     os << path;
351     os << '\0';
352   };
353 
354   addDep(DepOpCode::Version, version);
355 
356   // Sort the input by its names.
357   std::vector<StringRef> inputNames;
358   inputNames.reserve(inputs.size());
359   for (InputFile *f : inputs)
360     inputNames.push_back(f->getName());
361   llvm::sort(inputNames);
362 
363   for (const StringRef &in : inputNames)
364     addDep(DepOpCode::Input, in);
365 
366   for (const std::string &f : notFounds)
367     addDep(DepOpCode::NotFound, f);
368 
369   addDep(DepOpCode::Output, output);
370 }
371