1 //===- DriverUtils.cpp ----------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains utility functions for the driver. Because there
10 // are so many small functions, we created this separate file to make
11 // Driver.cpp less cluttered.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "Driver.h"
16 #include "lld/Common/ErrorHandler.h"
17 #include "lld/Common/Memory.h"
18 #include "lld/Common/Reproduce.h"
19 #include "lld/Common/Version.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/Option/Option.h"
24 #include "llvm/Support/CommandLine.h"
25 #include "llvm/Support/FileSystem.h"
26 #include "llvm/Support/Host.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/Process.h"
29 #include "llvm/Support/TimeProfiler.h"
30 
31 using namespace llvm;
32 using namespace llvm::sys;
33 using namespace llvm::opt;
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     lld::errs().enable_colors(true);
64   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
65     lld::errs().enable_colors(false);
66   } else {
67     StringRef s = arg->getValue();
68     if (s == "always")
69       lld::errs().enable_colors(true);
70     else if (s == "never")
71       lld::errs().enable_colors(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()).isOSWindows())
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 (opt::Arg *arg : args.filtered(OPT_UNKNOWN)) {
137     std::string nearest;
138     if (findNearest(arg->getAsString(args), nearest) > 1)
139       error("unknown argument '" + arg->getAsString(args) + "'");
140     else
141       error("unknown argument '" + arg->getAsString(args) +
142             "', did you mean '" + nearest + "'");
143   }
144   return args;
145 }
146 
147 void elf::printHelp() {
148   ELFOptTable().PrintHelp(
149       lld::outs(), (config->progName + " [options] file...").str().c_str(),
150       "lld", false /*ShowHidden*/, true /*ShowAllAliases*/);
151   lld::outs() << "\n";
152 
153   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
154   // recent version as of March 2017) expect /: supported targets:.* elf/
155   // in a message for the -help option. If it doesn't match, the scripts
156   // assume that the linker doesn't support very basic features such as
157   // shared libraries. Therefore, we need to print out at least "elf".
158   lld::outs() << config->progName << ": supported targets: elf\n";
159 }
160 
161 static std::string rewritePath(StringRef s) {
162   if (fs::exists(s))
163     return relativeToRoot(s);
164   return std::string(s);
165 }
166 
167 // Reconstructs command line arguments so that so that you can re-run
168 // the same command with the same inputs. This is for --reproduce.
169 std::string elf::createResponseFile(const opt::InputArgList &args) {
170   SmallString<0> data;
171   raw_svector_ostream os(data);
172   os << "--chroot .\n";
173 
174   // Copy the command line to the output while rewriting paths.
175   for (auto *arg : args) {
176     switch (arg->getOption().getID()) {
177     case OPT_reproduce:
178       break;
179     case OPT_INPUT:
180       os << quote(rewritePath(arg->getValue())) << "\n";
181       break;
182     case OPT_o:
183       // If -o path contains directories, "lld @response.txt" will likely
184       // fail because the archive we are creating doesn't contain empty
185       // directories for the output path (-o doesn't create directories).
186       // Strip directories to prevent the issue.
187       os << "-o " << quote(path::filename(arg->getValue())) << "\n";
188       break;
189     case OPT_call_graph_ordering_file:
190     case OPT_dynamic_list:
191     case OPT_just_symbols:
192     case OPT_library_path:
193     case OPT_retain_symbols_file:
194     case OPT_rpath:
195     case OPT_script:
196     case OPT_symbol_ordering_file:
197     case OPT_sysroot:
198     case OPT_version_script:
199       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
200          << "\n";
201       break;
202     default:
203       os << toString(*arg) << "\n";
204     }
205   }
206   return std::string(data.str());
207 }
208 
209 // Find a file by concatenating given paths. If a resulting path
210 // starts with "=", the character is replaced with a --sysroot value.
211 static Optional<std::string> findFile(StringRef path1, const Twine &path2) {
212   SmallString<128> s;
213   if (path1.startswith("="))
214     path::append(s, config->sysroot, path1.substr(1), path2);
215   else
216     path::append(s, path1, path2);
217 
218   if (fs::exists(s))
219     return std::string(s);
220   return None;
221 }
222 
223 Optional<std::string> elf::findFromSearchPaths(StringRef path) {
224   for (StringRef dir : config->searchPaths)
225     if (Optional<std::string> s = findFile(dir, path))
226       return s;
227   return None;
228 }
229 
230 // This is for -l<basename>. We'll look for lib<basename>.so or lib<basename>.a from
231 // search paths.
232 Optional<std::string> elf::searchLibraryBaseName(StringRef name) {
233   for (StringRef dir : config->searchPaths) {
234     if (!config->isStatic)
235       if (Optional<std::string> s = findFile(dir, "lib" + name + ".so"))
236         return s;
237     if (Optional<std::string> s = findFile(dir, "lib" + name + ".a"))
238       return s;
239   }
240   return None;
241 }
242 
243 // This is for -l<namespec>.
244 Optional<std::string> elf::searchLibrary(StringRef name) {
245   llvm::TimeTraceScope timeScope("Locate library", name);
246   if (name.startswith(":"))
247     return findFromSearchPaths(name.substr(1));
248   return searchLibraryBaseName(name);
249 }
250 
251 // If a linker/version script doesn't exist in the current directory, we also
252 // look for the script in the '-L' search paths. This matches the behaviour of
253 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
254 Optional<std::string> elf::searchScript(StringRef name) {
255   if (fs::exists(name))
256     return name.str();
257   return findFromSearchPaths(name);
258 }
259