1 //===- DriverUtils.cpp ----------------------------------------------------===//
2 //
3 //                             The LLVM Linker
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains utility functions for the driver. Because there
11 // are so many small functions, we created this separate file to make
12 // Driver.cpp less cluttered.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "Driver.h"
17 #include "Error.h"
18 #include "lld/Config/Version.h"
19 #include "llvm/ADT/STLExtras.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/Path.h"
25 #include "llvm/Support/StringSaver.h"
26 
27 using namespace llvm;
28 using namespace llvm::sys;
29 
30 using namespace lld;
31 using namespace lld::elf;
32 
33 // Create OptTable
34 
35 // Create prefix string literals used in Options.td
36 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
37 #include "ELF/Options.inc"
38 #undef PREFIX
39 
40 // Create table mapping all options defined in Options.td
41 static const opt::OptTable::Info OptInfo[] = {
42 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
43   {                                                                            \
44     X1, X2, X9, X10, OPT_##ID, opt::Option::KIND##Class, X8, X7, OPT_##GROUP,  \
45         OPT_##ALIAS, X6                                                        \
46   },
47 #include "ELF/Options.inc"
48 #undef OPTION
49 };
50 
51 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
52 
53 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
54   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
55     StringRef S = Arg->getValue();
56     if (S != "windows" && S != "posix")
57       error("invalid response file quoting: " + S);
58     if (S == "windows")
59       return cl::TokenizeWindowsCommandLine;
60     return cl::TokenizeGNUCommandLine;
61   }
62   if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
63     return cl::TokenizeWindowsCommandLine;
64   return cl::TokenizeGNUCommandLine;
65 }
66 
67 // Parses a given list of options.
68 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
69   // Make InputArgList from string vectors.
70   unsigned MissingIndex;
71   unsigned MissingCount;
72   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
73 
74   // We need to get the quoting style for response files before parsing all
75   // options so we parse here before and ignore all the options but
76   // --rsp-quoting.
77   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
78 
79   // Expand response files. '@<filename>' is replaced by the file's contents.
80   StringSaver Saver(Alloc);
81   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
82 
83   // Parse options and then do error checking.
84   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
85   if (MissingCount)
86     error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
87           "\", expected " + Twine(MissingCount) +
88           (MissingCount == 1 ? " argument.\n" : " arguments"));
89 
90   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
91     error("unknown argument: " + Arg->getSpelling());
92   return Args;
93 }
94 
95 void elf::printHelp(const char *Argv0) {
96   ELFOptTable Table;
97   Table.PrintHelp(outs(), Argv0, "lld", false);
98 }
99 
100 std::string elf::getVersionString() {
101   std::string Version = getLLDVersion();
102   std::string Repo = getLLDRepositoryVersion();
103   if (Repo.empty())
104     return "LLD " + Version + "\n";
105   return "LLD " + Version + " " + Repo + "\n";
106 }
107 
108 // Makes a given pathname an absolute path first, and then remove
109 // beginning /. For example, "../foo.o" is converted to "home/john/foo.o",
110 // assuming that the current directory is "/home/john/bar".
111 std::string elf::relativeToRoot(StringRef Path) {
112   SmallString<128> Abs = Path;
113   if (std::error_code EC = fs::make_absolute(Abs))
114     fatal("make_absolute failed: " + EC.message());
115   path::remove_dots(Abs, /*remove_dot_dot=*/true);
116 
117   // This is Windows specific. root_name() returns a drive letter
118   // (e.g. "c:") or a UNC name (//net). We want to keep it as part
119   // of the result.
120   SmallString<128> Res;
121   StringRef Root = path::root_name(Abs);
122   if (Root.endswith(":"))
123     Res = Root.drop_back();
124   else if (Root.startswith("//"))
125     Res = Root.substr(2);
126 
127   path::append(Res, path::relative_path(Abs));
128   return Res.str();
129 }
130 
131 CpioFile::CpioFile(std::unique_ptr<raw_fd_ostream> OS, StringRef S)
132     : OS(std::move(OS)), Basename(S) {}
133 
134 CpioFile *CpioFile::create(StringRef OutputPath) {
135   std::string Path = (OutputPath + ".cpio").str();
136   std::error_code EC;
137   auto OS = llvm::make_unique<raw_fd_ostream>(Path, EC, fs::F_None);
138   if (EC) {
139     error(EC, "--reproduce: failed to open " + Path);
140     return nullptr;
141   }
142   return new CpioFile(std::move(OS), path::filename(OutputPath));
143 }
144 
145 static void writeMember(raw_fd_ostream &OS, StringRef Path, StringRef Data) {
146   // The c_dev/c_ino pair should be unique according to the spec,
147   // but no one seems to care.
148   OS << "070707";                        // c_magic
149   OS << "000000";                        // c_dev
150   OS << "000000";                        // c_ino
151   OS << "100664";                        // c_mode: C_ISREG | rw-rw-r--
152   OS << "000000";                        // c_uid
153   OS << "000000";                        // c_gid
154   OS << "000001";                        // c_nlink
155   OS << "000000";                        // c_rdev
156   OS << "00000000000";                   // c_mtime
157   OS << format("%06o", Path.size() + 1); // c_namesize
158   OS << format("%011o", Data.size());    // c_filesize
159   OS << Path << '\0';                    // c_name
160   OS << Data;                            // c_filedata
161 }
162 
163 void CpioFile::append(StringRef Path, StringRef Data) {
164   if (!Seen.insert(Path).second)
165     return;
166 
167   // Construct an in-archive filename so that /home/foo/bar is stored
168   // as baz/home/foo/bar where baz is the basename of the output file.
169   // (i.e. in that case we are creating baz.cpio.)
170   SmallString<128> Fullpath;
171   path::append(Fullpath, Basename, Path);
172 
173   // Use unix path separators so the cpio can be extracted on both unix and
174   // windows.
175   std::replace(Fullpath.begin(), Fullpath.end(), '\\', '/');
176 
177   writeMember(*OS, Fullpath, Data);
178 
179   // Print the trailer and seek back.
180   // This way we have a valid archive if we crash.
181   uint64_t Pos = OS->tell();
182   writeMember(*OS, "TRAILER!!!", "");
183   OS->seek(Pos);
184 }
185 
186 // Quote a given string if it contains a space character.
187 static std::string quote(StringRef S) {
188   if (S.find(' ') == StringRef::npos)
189     return S;
190   return ("\"" + S + "\"").str();
191 }
192 
193 static std::string rewritePath(StringRef S) {
194   if (fs::exists(S))
195     return relativeToRoot(S);
196   return S;
197 }
198 
199 static std::string stringize(opt::Arg *Arg) {
200   std::string K = Arg->getSpelling();
201   if (Arg->getNumValues() == 0)
202     return K;
203   std::string V = quote(Arg->getValue());
204   if (Arg->getOption().getRenderStyle() == opt::Option::RenderJoinedStyle)
205     return K + V;
206   return K + " " + V;
207 }
208 
209 // Reconstructs command line arguments so that so that you can re-run
210 // the same command with the same inputs. This is for --reproduce.
211 std::string elf::createResponseFile(const opt::InputArgList &Args) {
212   SmallString<0> Data;
213   raw_svector_ostream OS(Data);
214 
215   // Copy the command line to the output while rewriting paths.
216   for (auto *Arg : Args) {
217     switch (Arg->getOption().getID()) {
218     case OPT_reproduce:
219       break;
220     case OPT_INPUT:
221       OS << quote(rewritePath(Arg->getValue())) << "\n";
222       break;
223     case OPT_L:
224     case OPT_dynamic_list:
225     case OPT_rpath:
226     case OPT_alias_script_T:
227     case OPT_script:
228     case OPT_version_script:
229       OS << Arg->getSpelling() << " "
230          << quote(rewritePath(Arg->getValue())) << "\n";
231       break;
232     default:
233       OS << stringize(Arg) << "\n";
234     }
235   }
236   return Data.str();
237 }
238 
239 std::string elf::findFromSearchPaths(StringRef Path) {
240   for (StringRef Dir : Config->SearchPaths) {
241     std::string FullPath = buildSysrootedPath(Dir, Path);
242     if (fs::exists(FullPath))
243       return FullPath;
244   }
245   return "";
246 }
247 
248 // Searches a given library from input search paths, which are filled
249 // from -L command line switches. Returns a path to an existent library file.
250 std::string elf::searchLibrary(StringRef Path) {
251   if (Path.startswith(":"))
252     return findFromSearchPaths(Path.substr(1));
253   for (StringRef Dir : Config->SearchPaths) {
254     if (!Config->Static) {
255       std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".so").str());
256       if (fs::exists(S))
257         return S;
258     }
259     std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".a").str());
260     if (fs::exists(S))
261       return S;
262   }
263   return "";
264 }
265 
266 // Makes a path by concatenating Dir and File.
267 // If Dir starts with '=' the result will be preceded by Sysroot,
268 // which can be set with --sysroot command line switch.
269 std::string elf::buildSysrootedPath(StringRef Dir, StringRef File) {
270   SmallString<128> Path;
271   if (Dir.startswith("="))
272     path::append(Path, Config->Sysroot, Dir.substr(1), File);
273   else
274     path::append(Path, Dir, File);
275   return Path.str();
276 }
277