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/Option/Option.h"
21 #include "llvm/Support/CommandLine.h"
22 #include "llvm/Support/FileSystem.h"
23 #include "llvm/Support/Path.h"
24 #include "llvm/Support/StringSaver.h"
25 
26 using namespace llvm;
27 using namespace llvm::sys;
28 
29 using namespace lld;
30 using namespace lld::elf;
31 
32 // Create OptTable
33 
34 // Create prefix string literals used in Options.td
35 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
36 #include "Options.inc"
37 #undef PREFIX
38 
39 // Create table mapping all options defined in Options.td
40 static const opt::OptTable::Info OptInfo[] = {
41 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
42   {                                                                            \
43     X1, X2, X9, X10, OPT_##ID, opt::Option::KIND##Class, X8, X7, OPT_##GROUP,  \
44         OPT_##ALIAS, X6                                                        \
45   },
46 #include "Options.inc"
47 #undef OPTION
48 };
49 
50 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
51 
52 // Parses a given list of options.
53 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
54   // Make InputArgList from string vectors.
55   unsigned MissingIndex;
56   unsigned MissingCount;
57 
58   // Expand response files. '@<filename>' is replaced by the file's contents.
59   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
60   StringSaver Saver(Alloc);
61   cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, Vec);
62 
63   // Parse options and then do error checking.
64   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
65   if (MissingCount)
66     error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
67           "\", expected " + Twine(MissingCount) +
68           (MissingCount == 1 ? " argument.\n" : " arguments"));
69 
70   iterator_range<opt::arg_iterator> Unknowns = Args.filtered(OPT_UNKNOWN);
71   for (auto *Arg : Unknowns)
72     warning("warning: unknown argument: " + Arg->getSpelling());
73   if (Unknowns.begin() != Unknowns.end())
74     error("unknown argument(s) found");
75   return Args;
76 }
77 
78 void elf::printHelp(const char *Argv0) {
79   ELFOptTable Table;
80   Table.PrintHelp(outs(), Argv0, "lld", false);
81 }
82 
83 void elf::printVersion() {
84   outs() << "LLD " << getLLDVersion();
85   std::string S = getLLDRepositoryVersion();
86   if (!S.empty())
87     outs() << " " << S;
88   outs() << "\n";
89 }
90 
91 // Makes a given pathname an absolute path first, and then remove
92 // beginning /. For example, "../foo.o" is converted to "home/john/foo.o",
93 // assuming that the current directory is "/home/john/bar".
94 static std::string relativeToRoot(StringRef Path) {
95   SmallString<128> Abs = Path;
96   if (std::error_code EC = fs::make_absolute(Abs))
97     fatal("make_absolute failed: " + EC.message());
98   path::remove_dots(Abs, /*remove_dot_dot=*/true);
99 
100   // This is Windows specific. root_name() returns a drive letter
101   // (e.g. "c:") or a UNC name (//net). We want to keep it as part
102   // of the result.
103   SmallString<128> Res;
104   StringRef Root = path::root_name(Abs);
105   if (Root.endswith(":"))
106     Res = Root.drop_back();
107   else if (Root.startswith("//"))
108     Res = Root.substr(2);
109 
110   path::append(Res, path::relative_path(Abs));
111   return Res.str();
112 }
113 
114 static std::string getDestPath(StringRef Path) {
115   std::string Relpath = relativeToRoot(Path);
116   SmallString<128> Dest;
117   path::append(Dest, path::filename(Config->Reproduce), Relpath);
118   return Dest.str();
119 }
120 
121 static void maybePrintCpioMemberAux(raw_fd_ostream &OS, StringRef Path,
122                                     StringRef Data) {
123   OS << "070707"; // c_magic
124 
125   // The c_dev/c_ino pair should be unique according to the spec, but no one
126   // seems to care.
127   OS << "000000"; // c_dev
128   OS << "000000"; // c_ino
129 
130   OS << "100664";                        // c_mode: C_ISREG | rw-rw-r--
131   OS << "000000";                        // c_uid
132   OS << "000000";                        // c_gid
133   OS << "000001";                        // c_nlink
134   OS << "000000";                        // c_rdev
135   OS << "00000000000";                   // c_mtime
136   OS << format("%06o", Path.size() + 1); // c_namesize
137   OS << format("%011o", Data.size());    // c_filesize
138   OS << Path << '\0';                    // c_name
139   OS << Data;                            // c_filedata
140 }
141 
142 static void maybePrintCpioMember(StringRef Path, StringRef Data) {
143   if (Config->Reproduce.empty())
144     return;
145 
146   if (!Driver->IncludedFiles.insert(Path).second)
147     return;
148   raw_fd_ostream &OS = *Driver->ReproduceArchive;
149   maybePrintCpioMemberAux(OS, Path, Data);
150 
151   // Print the trailer and seek back. This way we have a valid archive if we
152   // crash.
153   // See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_11
154   // for the format details.
155   uint64_t Pos = OS.tell();
156   maybePrintCpioMemberAux(OS, "TRAILER!!!", "");
157   OS.seek(Pos);
158 }
159 
160 // Write file Src with content Data to the archive.
161 void elf::maybeCopyInputFile(StringRef Src, StringRef Data) {
162   std::string Dest = getDestPath(Src);
163   maybePrintCpioMember(Dest, Data);
164 }
165 
166 // Quote a given string if it contains a space character.
167 static std::string quote(StringRef S) {
168   if (S.find(' ') == StringRef::npos)
169     return S;
170   return ("\"" + S + "\"").str();
171 }
172 
173 static std::string rewritePath(StringRef S) {
174   if (fs::exists(S))
175     return relativeToRoot(S);
176   return S;
177 }
178 
179 static std::string stringize(opt::Arg *Arg) {
180   std::string K = Arg->getSpelling();
181   if (Arg->getNumValues() == 0)
182     return K;
183   std::string V = quote(Arg->getValue());
184   if (Arg->getOption().getRenderStyle() == opt::Option::RenderJoinedStyle)
185     return K + V;
186   return K + " " + V;
187 }
188 
189 // Copies all input files to Config->Reproduce directory and
190 // create a response file as "response.txt", so that you can re-run
191 // the same command with the same inputs just by executing
192 // "ld.lld @response.txt". Used by --reproduce. This feature is
193 // supposed to be used by users to report an issue to LLD developers.
194 void elf::createResponseFile(const opt::InputArgList &Args) {
195   SmallString<0> Data;
196   raw_svector_ostream OS(Data);
197   // Copy the command line to response.txt while rewriting paths.
198   for (auto *Arg : Args) {
199     switch (Arg->getOption().getID()) {
200     case OPT_reproduce:
201       break;
202     case OPT_INPUT:
203       OS << quote(rewritePath(Arg->getValue())) << "\n";
204       break;
205     case OPT_L:
206     case OPT_dynamic_list:
207     case OPT_rpath:
208     case OPT_script:
209     case OPT_version_script:
210       OS << Arg->getSpelling() << " "
211          << quote(rewritePath(Arg->getValue())) << "\n";
212       break;
213     default:
214       OS << stringize(Arg) << "\n";
215     }
216   }
217 
218   SmallString<128> Dest;
219   path::append(Dest, path::filename(Config->Reproduce), "response.txt");
220   maybePrintCpioMember(Dest, Data);
221 }
222 
223 std::string elf::findFromSearchPaths(StringRef Path) {
224   for (StringRef Dir : Config->SearchPaths) {
225     std::string FullPath = buildSysrootedPath(Dir, Path);
226     if (fs::exists(FullPath))
227       return FullPath;
228   }
229   return "";
230 }
231 
232 // Searches a given library from input search paths, which are filled
233 // from -L command line switches. Returns a path to an existent library file.
234 std::string elf::searchLibrary(StringRef Path) {
235   if (Path.startswith(":"))
236     return findFromSearchPaths(Path.substr(1));
237   if (!Config->Static) {
238     std::string S = findFromSearchPaths(("lib" + Path + ".so").str());
239     if (!S.empty())
240       return S;
241   }
242   return findFromSearchPaths(("lib" + Path + ".a").str());
243 }
244 
245 // Makes a path by concatenating Dir and File.
246 // If Dir starts with '=' the result will be preceded by Sysroot,
247 // which can be set with --sysroot command line switch.
248 std::string elf::buildSysrootedPath(StringRef Dir, StringRef File) {
249   SmallString<128> Path;
250   if (Dir.startswith("="))
251     path::append(Path, Config->Sysroot, Dir.substr(1), File);
252   else
253     path::append(Path, Dir, File);
254   return Path.str();
255 }
256