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 std::string elf::getVersionString() {
84   std::string Version = getLLDVersion();
85   std::string Repo = getLLDRepositoryVersion();
86   if (Repo.empty())
87     return "LLD " + Version + "\n";
88   return "LLD " + Version + " " + Repo + "\n";
89 }
90 
91 // Converts a hex string (e.g. "0x123456") to a vector.
92 std::vector<uint8_t> elf::parseHexstring(StringRef S) {
93   if (S.find_first_not_of("0123456789abcdefABCDEF") != StringRef::npos ||
94       S.size() % 2) {
95     error("malformed hexstring: " + S);
96     return {};
97   }
98   std::vector<uint8_t> V;
99   for (; !S.empty(); S = S.substr(2)) {
100     int I;
101     S.substr(0, 2).getAsInteger(16, I);
102     V.push_back(I);
103   }
104   return V;
105 }
106 
107 // Makes a given pathname an absolute path first, and then remove
108 // beginning /. For example, "../foo.o" is converted to "home/john/foo.o",
109 // assuming that the current directory is "/home/john/bar".
110 std::string elf::relativeToRoot(StringRef Path) {
111   SmallString<128> Abs = Path;
112   if (std::error_code EC = fs::make_absolute(Abs))
113     fatal("make_absolute failed: " + EC.message());
114   path::remove_dots(Abs, /*remove_dot_dot=*/true);
115 
116   // This is Windows specific. root_name() returns a drive letter
117   // (e.g. "c:") or a UNC name (//net). We want to keep it as part
118   // of the result.
119   SmallString<128> Res;
120   StringRef Root = path::root_name(Abs);
121   if (Root.endswith(":"))
122     Res = Root.drop_back();
123   else if (Root.startswith("//"))
124     Res = Root.substr(2);
125 
126   path::append(Res, path::relative_path(Abs));
127   return Res.str();
128 }
129 
130 CpioFile::CpioFile(std::unique_ptr<llvm::raw_fd_ostream> OS, StringRef S)
131     : OS(std::move(OS)), Basename(S) {}
132 
133 CpioFile *CpioFile::create(StringRef OutputPath) {
134   std::string Path = (OutputPath + ".cpio").str();
135   std::error_code EC;
136   auto OS = llvm::make_unique<raw_fd_ostream>(Path, EC, fs::F_None);
137   if (EC) {
138     error(EC, "--reproduce: failed to open " + Path);
139     return nullptr;
140   }
141   return new CpioFile(std::move(OS), path::filename(OutputPath));
142 }
143 
144 static void writeMember(raw_fd_ostream &OS, StringRef Path, StringRef Data) {
145   // The c_dev/c_ino pair should be unique according to the spec,
146   // but no one seems to care.
147   OS << "070707";                        // c_magic
148   OS << "000000";                        // c_dev
149   OS << "000000";                        // c_ino
150   OS << "100664";                        // c_mode: C_ISREG | rw-rw-r--
151   OS << "000000";                        // c_uid
152   OS << "000000";                        // c_gid
153   OS << "000001";                        // c_nlink
154   OS << "000000";                        // c_rdev
155   OS << "00000000000";                   // c_mtime
156   OS << format("%06o", Path.size() + 1); // c_namesize
157   OS << format("%011o", Data.size());    // c_filesize
158   OS << Path << '\0';                    // c_name
159   OS << Data;                            // c_filedata
160 }
161 
162 void CpioFile::append(StringRef Path, StringRef Data) {
163   if (!Seen.insert(Path).second)
164     return;
165 
166   // Construct an in-archive filename so that /home/foo/bar is stored
167   // as baz/home/foo/bar where baz is the basename of the output file.
168   // (i.e. in that case we are creating baz.cpio.)
169   SmallString<128> Fullpath;
170   path::append(Fullpath, Basename, Path);
171   writeMember(*OS, Fullpath, Data);
172 
173   // Print the trailer and seek back.
174   // This way we have a valid archive if we crash.
175   uint64_t Pos = OS->tell();
176   writeMember(*OS, "TRAILER!!!", "");
177   OS->seek(Pos);
178 }
179 
180 // Quote a given string if it contains a space character.
181 static std::string quote(StringRef S) {
182   if (S.find(' ') == StringRef::npos)
183     return S;
184   return ("\"" + S + "\"").str();
185 }
186 
187 static std::string rewritePath(StringRef S) {
188   if (fs::exists(S))
189     return relativeToRoot(S);
190   return S;
191 }
192 
193 static std::string stringize(opt::Arg *Arg) {
194   std::string K = Arg->getSpelling();
195   if (Arg->getNumValues() == 0)
196     return K;
197   std::string V = quote(Arg->getValue());
198   if (Arg->getOption().getRenderStyle() == opt::Option::RenderJoinedStyle)
199     return K + V;
200   return K + " " + V;
201 }
202 
203 // Reconstructs command line arguments so that so that you can re-run
204 // the same command with the same inputs. This is for --reproduce.
205 std::string elf::createResponseFile(const opt::InputArgList &Args) {
206   SmallString<0> Data;
207   raw_svector_ostream OS(Data);
208 
209   // Copy the command line to the output while rewriting paths.
210   for (auto *Arg : Args) {
211     switch (Arg->getOption().getID()) {
212     case OPT_reproduce:
213       break;
214     case OPT_INPUT:
215       OS << quote(rewritePath(Arg->getValue())) << "\n";
216       break;
217     case OPT_L:
218     case OPT_dynamic_list:
219     case OPT_rpath:
220     case OPT_alias_script_T:
221     case OPT_script:
222     case OPT_version_script:
223       OS << Arg->getSpelling() << " "
224          << quote(rewritePath(Arg->getValue())) << "\n";
225       break;
226     default:
227       OS << stringize(Arg) << "\n";
228     }
229   }
230   return Data.str();
231 }
232 
233 std::string elf::findFromSearchPaths(StringRef Path) {
234   for (StringRef Dir : Config->SearchPaths) {
235     std::string FullPath = buildSysrootedPath(Dir, Path);
236     if (fs::exists(FullPath))
237       return FullPath;
238   }
239   return "";
240 }
241 
242 // Searches a given library from input search paths, which are filled
243 // from -L command line switches. Returns a path to an existent library file.
244 std::string elf::searchLibrary(StringRef Path) {
245   if (Path.startswith(":"))
246     return findFromSearchPaths(Path.substr(1));
247   if (!Config->Static) {
248     std::string S = findFromSearchPaths(("lib" + Path + ".so").str());
249     if (!S.empty())
250       return S;
251   }
252   return findFromSearchPaths(("lib" + Path + ".a").str());
253 }
254 
255 // Makes a path by concatenating Dir and File.
256 // If Dir starts with '=' the result will be preceded by Sysroot,
257 // which can be set with --sysroot command line switch.
258 std::string elf::buildSysrootedPath(StringRef Dir, StringRef File) {
259   SmallString<128> Path;
260   if (Dir.startswith("="))
261     path::append(Path, Config->Sysroot, Dir.substr(1), File);
262   else
263     path::append(Path, Dir, File);
264   return Path.str();
265 }
266