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/Path.h"
27 #include "llvm/Support/Process.h"
28 
29 using namespace llvm;
30 using namespace llvm::sys;
31 using namespace llvm::opt;
32 
33 using namespace lld;
34 using namespace lld::elf;
35 
36 // Create OptTable
37 
38 // Create prefix string literals used in Options.td
39 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
40 #include "Options.inc"
41 #undef PREFIX
42 
43 // Create table mapping all options defined in Options.td
44 static const opt::OptTable::Info OptInfo[] = {
45 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
46   {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
47    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
48 #include "Options.inc"
49 #undef OPTION
50 };
51 
52 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
53 
54 // Set color diagnostics according to -color-diagnostics={auto,always,never}
55 // or -no-color-diagnostics flags.
56 static void handleColorDiagnostics(opt::InputArgList &Args) {
57   auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
58                               OPT_no_color_diagnostics);
59   if (!Arg)
60     return;
61   if (Arg->getOption().getID() == OPT_color_diagnostics) {
62     errorHandler().ColorDiagnostics = true;
63   } else if (Arg->getOption().getID() == OPT_no_color_diagnostics) {
64     errorHandler().ColorDiagnostics = false;
65   } else {
66     StringRef S = Arg->getValue();
67     if (S == "always")
68       errorHandler().ColorDiagnostics = true;
69     else if (S == "never")
70       errorHandler().ColorDiagnostics = false;
71     else if (S != "auto")
72       error("unknown option: --color-diagnostics=" + S);
73   }
74 }
75 
76 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
77   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
78     StringRef S = Arg->getValue();
79     if (S != "windows" && S != "posix")
80       error("invalid response file quoting: " + S);
81     if (S == "windows")
82       return cl::TokenizeWindowsCommandLine;
83     return cl::TokenizeGNUCommandLine;
84   }
85   if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
86     return cl::TokenizeWindowsCommandLine;
87   return cl::TokenizeGNUCommandLine;
88 }
89 
90 // Gold LTO plugin takes a `--plugin-opt foo=bar` option as an alias for
91 // `--plugin-opt=foo=bar`. We want to handle `--plugin-opt=foo=` as an
92 // option name and `bar` as a value. Unfortunately, OptParser cannot
93 // handle an option with a space in it.
94 //
95 // In this function, we concatenate command line arguments so that
96 // `--plugin-opt <foo>` is converted to `--plugin-opt=<foo>`. This is a
97 // bit hacky, but looks like it is still better than handling --plugin-opt
98 // options by hand.
99 static void concatLTOPluginOptions(SmallVectorImpl<const char *> &Args) {
100   SmallVector<const char *, 256> V;
101   for (size_t I = 0, E = Args.size(); I != E; ++I) {
102     StringRef S = Args[I];
103     if ((S == "-plugin-opt" || S == "--plugin-opt") && I + 1 != E) {
104       V.push_back(Saver.save(S + "=" + Args[I + 1]).data());
105       ++I;
106     } else {
107       V.push_back(Args[I]);
108     }
109   }
110   Args = std::move(V);
111 }
112 
113 // Parses a given list of options.
114 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
115   // Make InputArgList from string vectors.
116   unsigned MissingIndex;
117   unsigned MissingCount;
118   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
119 
120   // We need to get the quoting style for response files before parsing all
121   // options so we parse here before and ignore all the options but
122   // --rsp-quoting.
123   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
124 
125   // Expand response files (arguments in the form of @<filename>)
126   // and then parse the argument again.
127   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
128   concatLTOPluginOptions(Vec);
129   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
130 
131   handleColorDiagnostics(Args);
132   if (MissingCount)
133     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
134 
135   for (auto *Arg : Args.filtered(OPT_UNKNOWN)) {
136     std::string Nearest;
137     if (findNearest(Arg->getAsString(Args), Nearest) > 1)
138       error("unknown argument '" + Arg->getSpelling() + "'");
139     else
140       error("unknown argument '" + Arg->getSpelling() + "', did you mean '" +
141             Nearest + "'");
142   }
143   return Args;
144 }
145 
146 void elf::printHelp() {
147   ELFOptTable().PrintHelp(
148       outs(), (Config->ProgName + " [options] file...").str().c_str(), "lld",
149       false /*ShowHidden*/, true /*ShowAllAliases*/);
150   outs() << "\n";
151 
152   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
153   // recent version as of March 2017) expect /: supported targets:.* elf/
154   // in a message for the -help option. If it doesn't match, the scripts
155   // assume that the linker doesn't support very basic features such as
156   // shared libraries. Therefore, we need to print out at least "elf".
157   outs() << Config->ProgName << ": supported targets: elf\n";
158 }
159 
160 static std::string rewritePath(StringRef S) {
161   if (fs::exists(S))
162     return relativeToRoot(S);
163   return S;
164 }
165 
166 // Reconstructs command line arguments so that so that you can re-run
167 // the same command with the same inputs. This is for --reproduce.
168 std::string elf::createResponseFile(const opt::InputArgList &Args) {
169   SmallString<0> Data;
170   raw_svector_ostream OS(Data);
171   OS << "--chroot .\n";
172 
173   // Copy the command line to the output while rewriting paths.
174   for (auto *Arg : Args) {
175     switch (Arg->getOption().getUnaliasedOption().getID()) {
176     case OPT_reproduce:
177       break;
178     case OPT_INPUT:
179       OS << quote(rewritePath(Arg->getValue())) << "\n";
180       break;
181     case OPT_o:
182       // If -o path contains directories, "lld @response.txt" will likely
183       // fail because the archive we are creating doesn't contain empty
184       // directories for the output path (-o doesn't create directories).
185       // Strip directories to prevent the issue.
186       OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
187       break;
188     case OPT_dynamic_list:
189     case OPT_library_path:
190     case OPT_rpath:
191     case OPT_script:
192     case OPT_symbol_ordering_file:
193     case OPT_sysroot:
194     case OPT_version_script:
195       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
196          << "\n";
197       break;
198     default:
199       OS << toString(*Arg) << "\n";
200     }
201   }
202   return Data.str();
203 }
204 
205 // Find a file by concatenating given paths. If a resulting path
206 // starts with "=", the character is replaced with a --sysroot value.
207 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
208   SmallString<128> S;
209   if (Path1.startswith("="))
210     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
211   else
212     path::append(S, Path1, Path2);
213 
214   if (fs::exists(S))
215     return S.str().str();
216   return None;
217 }
218 
219 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
220   for (StringRef Dir : Config->SearchPaths)
221     if (Optional<std::string> S = findFile(Dir, Path))
222       return S;
223   return None;
224 }
225 
226 // This is for -l<basename>. We'll look for lib<basename>.so or lib<basename>.a from
227 // search paths.
228 Optional<std::string> elf::searchLibraryBaseName(StringRef Name) {
229   for (StringRef Dir : Config->SearchPaths) {
230     if (!Config->Static)
231       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
232         return S;
233     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
234       return S;
235   }
236   return None;
237 }
238 
239 // This is for -l<namespec>.
240 Optional<std::string> elf::searchLibrary(StringRef Name) {
241     if (Name.startswith(":"))
242         return findFromSearchPaths(Name.substr(1));
243     return searchLibraryBaseName (Name);
244 }
245 
246 // If a linker/version script doesn't exist in the current directory, we also
247 // look for the script in the '-L' search paths. This matches the behaviour of
248 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
249 Optional<std::string> elf::searchScript(StringRef Name) {
250   if (fs::exists(Name))
251     return Name.str();
252   return findFromSearchPaths(Name);
253 }
254