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 // 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 std::string elf::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 CpioFile::CpioFile(std::unique_ptr<llvm::raw_fd_ostream> OS, StringRef S)
115     : OS(std::move(OS)), Basename(S) {}
116 
117 CpioFile *CpioFile::create(StringRef OutputPath) {
118   std::string Path = (OutputPath + ".cpio").str();
119   std::error_code EC;
120   auto OS = llvm::make_unique<raw_fd_ostream>(Path, EC, fs::F_None);
121   if (EC) {
122     error(EC, "--reproduce: failed to open " + Path);
123     return nullptr;
124   }
125   return new CpioFile(std::move(OS), path::filename(OutputPath));
126 }
127 
128 static void writeMember(raw_fd_ostream &OS, StringRef Path, StringRef Data) {
129   // The c_dev/c_ino pair should be unique according to the spec,
130   // but no one seems to care.
131   OS << "070707";                        // c_magic
132   OS << "000000";                        // c_dev
133   OS << "000000";                        // c_ino
134   OS << "100664";                        // c_mode: C_ISREG | rw-rw-r--
135   OS << "000000";                        // c_uid
136   OS << "000000";                        // c_gid
137   OS << "000001";                        // c_nlink
138   OS << "000000";                        // c_rdev
139   OS << "00000000000";                   // c_mtime
140   OS << format("%06o", Path.size() + 1); // c_namesize
141   OS << format("%011o", Data.size());    // c_filesize
142   OS << Path << '\0';                    // c_name
143   OS << Data;                            // c_filedata
144 }
145 
146 void CpioFile::append(StringRef Path, StringRef Data) {
147   if (!Seen.insert(Path).second)
148     return;
149 
150   // Construct an in-archive filename so that /home/foo/bar is stored
151   // as baz/home/foo/bar where baz is the basename of the output file.
152   // (i.e. in that case we are creating baz.cpio.)
153   SmallString<128> Fullpath;
154   path::append(Fullpath, Basename, Path);
155   writeMember(*OS, Fullpath, Data);
156 
157   // Print the trailer and seek back.
158   // This way we have a valid archive if we crash.
159   uint64_t Pos = OS->tell();
160   writeMember(*OS, "TRAILER!!!", "");
161   OS->seek(Pos);
162 }
163 
164 // Quote a given string if it contains a space character.
165 static std::string quote(StringRef S) {
166   if (S.find(' ') == StringRef::npos)
167     return S;
168   return ("\"" + S + "\"").str();
169 }
170 
171 static std::string rewritePath(StringRef S) {
172   if (fs::exists(S))
173     return relativeToRoot(S);
174   return S;
175 }
176 
177 static std::string stringize(opt::Arg *Arg) {
178   std::string K = Arg->getSpelling();
179   if (Arg->getNumValues() == 0)
180     return K;
181   std::string V = quote(Arg->getValue());
182   if (Arg->getOption().getRenderStyle() == opt::Option::RenderJoinedStyle)
183     return K + V;
184   return K + " " + V;
185 }
186 
187 // Reconstructs command line arguments so that so that you can re-run
188 // the same command with the same inputs. This is for --reproduce.
189 std::string elf::createResponseFile(const opt::InputArgList &Args) {
190   SmallString<0> Data;
191   raw_svector_ostream OS(Data);
192 
193   // Copy the command line to the output while rewriting paths.
194   for (auto *Arg : Args) {
195     switch (Arg->getOption().getID()) {
196     case OPT_reproduce:
197       break;
198     case OPT_INPUT:
199       OS << quote(rewritePath(Arg->getValue())) << "\n";
200       break;
201     case OPT_L:
202     case OPT_dynamic_list:
203     case OPT_rpath:
204     case OPT_alias_script_T:
205     case OPT_script:
206     case OPT_version_script:
207       OS << Arg->getSpelling() << " "
208          << quote(rewritePath(Arg->getValue())) << "\n";
209       break;
210     default:
211       OS << stringize(Arg) << "\n";
212     }
213   }
214   return Data.str();
215 }
216 
217 std::string elf::findFromSearchPaths(StringRef Path) {
218   for (StringRef Dir : Config->SearchPaths) {
219     std::string FullPath = buildSysrootedPath(Dir, Path);
220     if (fs::exists(FullPath))
221       return FullPath;
222   }
223   return "";
224 }
225 
226 // Searches a given library from input search paths, which are filled
227 // from -L command line switches. Returns a path to an existent library file.
228 std::string elf::searchLibrary(StringRef Path) {
229   if (Path.startswith(":"))
230     return findFromSearchPaths(Path.substr(1));
231   for (StringRef Dir : Config->SearchPaths) {
232     if (!Config->Static) {
233       std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".so").str());
234       if (fs::exists(S))
235         return S;
236     }
237     std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".a").str());
238     if (fs::exists(S))
239       return S;
240   }
241   return "";
242 }
243 
244 // Makes a path by concatenating Dir and File.
245 // If Dir starts with '=' the result will be preceded by Sysroot,
246 // which can be set with --sysroot command line switch.
247 std::string elf::buildSysrootedPath(StringRef Dir, StringRef File) {
248   SmallString<128> Path;
249   if (Dir.startswith("="))
250     path::append(Path, Config->Sysroot, Dir.substr(1), File);
251   else
252     path::append(Path, Dir, File);
253   return Path.str();
254 }
255