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     error("unknown argument: " + Arg->getSpelling());
137   return Args;
138 }
139 
140 void elf::printHelp() {
141   ELFOptTable().PrintHelp(
142       outs(), (Config->ProgName + " [options] file...").str().c_str(), "lld",
143       false /*ShowHidden*/, true /*ShowAllAliases*/);
144   outs() << "\n";
145 
146   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
147   // recent version as of March 2017) expect /: supported targets:.* elf/
148   // in a message for the -help option. If it doesn't match, the scripts
149   // assume that the linker doesn't support very basic features such as
150   // shared libraries. Therefore, we need to print out at least "elf".
151   outs() << Config->ProgName << ": supported targets: elf\n";
152 }
153 
154 static std::string rewritePath(StringRef S) {
155   if (fs::exists(S))
156     return relativeToRoot(S);
157   return S;
158 }
159 
160 // Reconstructs command line arguments so that so that you can re-run
161 // the same command with the same inputs. This is for --reproduce.
162 std::string elf::createResponseFile(const opt::InputArgList &Args) {
163   SmallString<0> Data;
164   raw_svector_ostream OS(Data);
165   OS << "--chroot .\n";
166 
167   // Copy the command line to the output while rewriting paths.
168   for (auto *Arg : Args) {
169     switch (Arg->getOption().getUnaliasedOption().getID()) {
170     case OPT_reproduce:
171       break;
172     case OPT_INPUT:
173       OS << quote(rewritePath(Arg->getValue())) << "\n";
174       break;
175     case OPT_o:
176       // If -o path contains directories, "lld @response.txt" will likely
177       // fail because the archive we are creating doesn't contain empty
178       // directories for the output path (-o doesn't create directories).
179       // Strip directories to prevent the issue.
180       OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
181       break;
182     case OPT_dynamic_list:
183     case OPT_library_path:
184     case OPT_rpath:
185     case OPT_script:
186     case OPT_symbol_ordering_file:
187     case OPT_sysroot:
188     case OPT_version_script:
189       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
190          << "\n";
191       break;
192     default:
193       OS << toString(*Arg) << "\n";
194     }
195   }
196   return Data.str();
197 }
198 
199 // Find a file by concatenating given paths. If a resulting path
200 // starts with "=", the character is replaced with a --sysroot value.
201 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
202   SmallString<128> S;
203   if (Path1.startswith("="))
204     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
205   else
206     path::append(S, Path1, Path2);
207 
208   if (fs::exists(S))
209     return S.str().str();
210   return None;
211 }
212 
213 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
214   for (StringRef Dir : Config->SearchPaths)
215     if (Optional<std::string> S = findFile(Dir, Path))
216       return S;
217   return None;
218 }
219 
220 // This is for -lfoo. We'll look for libfoo.so or libfoo.a from
221 // search paths.
222 Optional<std::string> elf::searchLibrary(StringRef Name) {
223   if (Name.startswith(":"))
224     return findFromSearchPaths(Name.substr(1));
225 
226   for (StringRef Dir : Config->SearchPaths) {
227     if (!Config->Static)
228       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
229         return S;
230     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
231       return S;
232   }
233   return None;
234 }
235 
236 // If a linker/version script doesn't exist in the current directory, we also
237 // look for the script in the '-L' search paths. This matches the behaviour of
238 // '-T', --version-script=, and linker script INPUT() command in ld.bfd.
239 Optional<std::string> elf::searchScript(StringRef Name) {
240   if (fs::exists(Name))
241     return Name.str();
242   return findFromSearchPaths(Name);
243 }
244