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 "lld/Common/ErrorHandler.h"
18 #include "lld/Common/Memory.h"
19 #include "lld/Common/Reproduce.h"
20 #include "lld/Common/Version.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/Option/Option.h"
25 #include "llvm/Support/CommandLine.h"
26 #include "llvm/Support/FileSystem.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/Process.h"
29 
30 using namespace llvm;
31 using namespace llvm::sys;
32 using namespace llvm::opt;
33 
34 using namespace lld;
35 using namespace lld::elf;
36 
37 // Create OptTable
38 
39 // Create prefix string literals used in Options.td
40 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
41 #include "Options.inc"
42 #undef PREFIX
43 
44 // Create table mapping all options defined in Options.td
45 static const opt::OptTable::Info OptInfo[] = {
46 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
47   {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
48    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
49 #include "Options.inc"
50 #undef OPTION
51 };
52 
53 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
54 
55 // Set color diagnostics according to -color-diagnostics={auto,always,never}
56 // or -no-color-diagnostics flags.
57 static void handleColorDiagnostics(opt::InputArgList &Args) {
58   auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
59                               OPT_no_color_diagnostics);
60   if (!Arg)
61     return;
62   if (Arg->getOption().getID() == OPT_color_diagnostics) {
63     errorHandler().ColorDiagnostics = true;
64   } else if (Arg->getOption().getID() == OPT_no_color_diagnostics) {
65     errorHandler().ColorDiagnostics = false;
66   } else {
67     StringRef S = Arg->getValue();
68     if (S == "always")
69       errorHandler().ColorDiagnostics = true;
70     else if (S == "never")
71       errorHandler().ColorDiagnostics = false;
72     else if (S != "auto")
73       error("unknown option: --color-diagnostics=" + S);
74   }
75 }
76 
77 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
78   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
79     StringRef S = Arg->getValue();
80     if (S != "windows" && S != "posix")
81       error("invalid response file quoting: " + S);
82     if (S == "windows")
83       return cl::TokenizeWindowsCommandLine;
84     return cl::TokenizeGNUCommandLine;
85   }
86   if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
87     return cl::TokenizeWindowsCommandLine;
88   return cl::TokenizeGNUCommandLine;
89 }
90 
91 // Gold LTO plugin takes a `--plugin-opt foo=bar` option as an alias for
92 // `--plugin-opt=foo=bar`. We want to handle `--plugin-opt=foo=` as an
93 // option name and `bar` as a value. Unfortunately, OptParser cannot
94 // handle an option with a space in it.
95 //
96 // In this function, we concatenate command line arguments so that
97 // `--plugin-opt <foo>` is converted to `--plugin-opt=<foo>`. This is a
98 // bit hacky, but looks like it is still better than handling --plugin-opt
99 // options by hand.
100 static void concatLTOPluginOptions(SmallVectorImpl<const char *> &Args) {
101   SmallVector<const char *, 256> V;
102   for (size_t I = 0, E = Args.size(); I != E; ++I) {
103     StringRef S = Args[I];
104     if ((S == "-plugin-opt" || S == "--plugin-opt") && I + 1 != E) {
105       V.push_back(Saver.save(S + "=" + Args[I + 1]).data());
106       ++I;
107     } else {
108       V.push_back(Args[I]);
109     }
110   }
111   Args = std::move(V);
112 }
113 
114 // Parses a given list of options.
115 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
116   // Make InputArgList from string vectors.
117   unsigned MissingIndex;
118   unsigned MissingCount;
119   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
120 
121   // We need to get the quoting style for response files before parsing all
122   // options so we parse here before and ignore all the options but
123   // --rsp-quoting.
124   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
125 
126   // Expand response files (arguments in the form of @<filename>)
127   // and then parse the argument again.
128   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
129   concatLTOPluginOptions(Vec);
130   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
131 
132   handleColorDiagnostics(Args);
133   if (MissingCount)
134     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
135 
136   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
137     error("unknown argument: " + Arg->getSpelling());
138   return Args;
139 }
140 
141 void elf::printHelp() {
142   ELFOptTable().PrintHelp(
143       outs(), (Config->ProgName + " [options] file...").str().c_str(), "lld",
144       false /*ShowHidden*/, true /*ShowAllAliases*/);
145   outs() << "\n";
146 
147   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
148   // recent version as of March 2017) expect /: supported targets:.* elf/
149   // in a message for the -help option. If it doesn't match, the scripts
150   // assume that the linker doesn't support very basic features such as
151   // shared libraries. Therefore, we need to print out at least "elf".
152   outs() << Config->ProgName << ": supported targets: elf\n";
153 }
154 
155 // Reconstructs command line arguments so that so that you can re-run
156 // the same command with the same inputs. This is for --reproduce.
157 std::string elf::createResponseFile(const opt::InputArgList &Args) {
158   SmallString<0> Data;
159   raw_svector_ostream OS(Data);
160   OS << "--chroot .\n";
161 
162   // Copy the command line to the output while rewriting paths.
163   for (auto *Arg : Args) {
164     switch (Arg->getOption().getUnaliasedOption().getID()) {
165     case OPT_reproduce:
166       break;
167     case OPT_INPUT:
168       OS << quote(rewritePath(Arg->getValue())) << "\n";
169       break;
170     case OPT_o:
171       // If -o path contains directories, "lld @response.txt" will likely
172       // fail because the archive we are creating doesn't contain empty
173       // directories for the output path (-o doesn't create directories).
174       // Strip directories to prevent the issue.
175       OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
176       break;
177     case OPT_dynamic_list:
178     case OPT_library_path:
179     case OPT_rpath:
180     case OPT_script:
181     case OPT_symbol_ordering_file:
182     case OPT_sysroot:
183     case OPT_version_script:
184       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
185          << "\n";
186       break;
187     default:
188       OS << toString(*Arg) << "\n";
189     }
190   }
191   return Data.str();
192 }
193 
194 // Find a file by concatenating given paths. If a resulting path
195 // starts with "=", the character is replaced with a --sysroot value.
196 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
197   SmallString<128> S;
198   if (Path1.startswith("="))
199     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
200   else
201     path::append(S, Path1, Path2);
202 
203   if (fs::exists(S))
204     return S.str().str();
205   return None;
206 }
207 
208 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
209   for (StringRef Dir : Config->SearchPaths)
210     if (Optional<std::string> S = findFile(Dir, Path))
211       return S;
212   return None;
213 }
214 
215 // This is for -lfoo. We'll look for libfoo.so or libfoo.a from
216 // search paths.
217 Optional<std::string> elf::searchLibrary(StringRef Name) {
218   if (Name.startswith(":"))
219     return findFromSearchPaths(Name.substr(1));
220 
221   for (StringRef Dir : Config->SearchPaths) {
222     if (!Config->Static)
223       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
224         return S;
225     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
226       return S;
227   }
228   return None;
229 }
230 
231 // If a linker/version script doesn't exist in the current directory, we also
232 // look for the script in the '-L' search paths. This matches the behaviour of
233 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
234 Optional<std::string> elf::searchScript(StringRef Name) {
235   if (fs::exists(Name))
236     return Name.str();
237   return findFromSearchPaths(Name);
238 }
239