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 "Memory.h"
19 #include "ScriptParser.h"
20 #include "lld/Config/Version.h"
21 #include "lld/Core/Reproduce.h"
22 #include "llvm/ADT/Optional.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/Option/Option.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/Path.h"
29 #include "llvm/Support/Process.h"
30 
31 using namespace llvm;
32 using namespace llvm::sys;
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 "ELF/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, X6, X7, X8, X9, X10)            \
47   {X1, X2, X9,          X10,         OPT_##ID, opt::Option::KIND##Class,       \
48    X8, X7, OPT_##GROUP, OPT_##ALIAS, X6},
49 #include "ELF/Options.inc"
50 #undef OPTION
51 };
52 
53 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
54 
55 // Parse -color-diagnostics={auto,always,never} or -no-color-diagnostics.
56 static bool getColorDiagnostics(opt::InputArgList &Args) {
57   bool Default = (ErrorOS == &errs() && Process::StandardErrHasColors());
58 
59   auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
60                               OPT_no_color_diagnostics);
61   if (!Arg)
62     return Default;
63   if (Arg->getOption().getID() == OPT_color_diagnostics)
64     return true;
65   if (Arg->getOption().getID() == OPT_no_color_diagnostics)
66     return false;
67 
68   StringRef S = Arg->getValue();
69   if (S == "auto")
70     return Default;
71   if (S == "always")
72     return true;
73   if (S != "never")
74     error("unknown option: -color-diagnostics=" + S);
75   return false;
76 }
77 
78 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
79   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
80     StringRef S = Arg->getValue();
81     if (S != "windows" && S != "posix")
82       error("invalid response file quoting: " + S);
83     if (S == "windows")
84       return cl::TokenizeWindowsCommandLine;
85     return cl::TokenizeGNUCommandLine;
86   }
87   if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
88     return cl::TokenizeWindowsCommandLine;
89   return cl::TokenizeGNUCommandLine;
90 }
91 
92 // Parses a given list of options.
93 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
94   // Make InputArgList from string vectors.
95   unsigned MissingIndex;
96   unsigned MissingCount;
97   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
98 
99   // We need to get the quoting style for response files before parsing all
100   // options so we parse here before and ignore all the options but
101   // --rsp-quoting.
102   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
103 
104   // Expand response files (arguments in the form of @<filename>)
105   // and then parse the argument again.
106   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
107   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
108 
109   // Interpret -color-diagnostics early so that error messages
110   // for unknown flags are colored.
111   Config->ColorDiagnostics = getColorDiagnostics(Args);
112   if (MissingCount)
113     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
114 
115   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
116     error("unknown argument: " + Arg->getSpelling());
117   return Args;
118 }
119 
120 void elf::printHelp(const char *Argv0) {
121   ELFOptTable Table;
122   Table.PrintHelp(outs(), Argv0, "lld", false);
123   outs() << "\n";
124 
125   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
126   // recent version as of March 2017) expect /supported targets:.* elf/ in
127   // a message for the -help option. If it doesn't match, the scripts
128   // assume that the linker doesn't support very basic features such as
129   // shared libraries. Therefore, we need to print out at least "elf".
130   // Here, we print out all the targets that we support.
131   outs() << Argv0 << ": supported targets: "
132          << "elf32-i386 elf32-iamcu elf32-littlearm elf32-powerpc "
133          << "elf32-tradbigmips elf32-tradlittlemips "
134          << "elf32-ntradbigmips elf32-ntradlittlemips elf32-x86-64 "
135          << "elf64-amdgpu elf64-littleaarch64 elf64-powerpc "
136          << "elf64-tradbigmips elf64-tradlittlemips elf64-x86-64\n";
137 }
138 
139 // Reconstructs command line arguments so that so that you can re-run
140 // the same command with the same inputs. This is for --reproduce.
141 std::string elf::createResponseFile(const opt::InputArgList &Args) {
142   SmallString<0> Data;
143   raw_svector_ostream OS(Data);
144 
145   // Copy the command line to the output while rewriting paths.
146   for (auto *Arg : Args) {
147     switch (Arg->getOption().getID()) {
148     case OPT_reproduce:
149       break;
150     case OPT_INPUT:
151       OS << quote(rewritePath(Arg->getValue())) << "\n";
152       break;
153     case OPT_L:
154     case OPT_dynamic_list:
155     case OPT_rpath:
156     case OPT_alias_script_T:
157     case OPT_script:
158     case OPT_version_script:
159       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
160          << "\n";
161       break;
162     default:
163       OS << toString(Arg) << "\n";
164     }
165   }
166   return Data.str();
167 }
168 
169 // Find a file by concatenating given paths. If a resulting path
170 // starts with "=", the character is replaced with a --sysroot value.
171 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
172   SmallString<128> S;
173   if (Path1.startswith("="))
174     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
175   else
176     path::append(S, Path1, Path2);
177 
178   if (fs::exists(S))
179     return S.str().str();
180   return None;
181 }
182 
183 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
184   for (StringRef Dir : Config->SearchPaths)
185     if (Optional<std::string> S = findFile(Dir, Path))
186       return S;
187   return None;
188 }
189 
190 // This is for -lfoo. We'll look for libfoo.so or libfoo.a from
191 // search paths.
192 Optional<std::string> elf::searchLibrary(StringRef Name) {
193   if (Name.startswith(":"))
194     return findFromSearchPaths(Name.substr(1));
195 
196   for (StringRef Dir : Config->SearchPaths) {
197     if (!Config->Static)
198       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
199         return S;
200     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
201       return S;
202   }
203   return None;
204 }
205