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 "lld/Config/Version.h"
20 #include "lld/Core/Reproduce.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 
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, X6, X7, X8, X9, X10)            \
46   {X1, X2, X9,          X10,         OPT_##ID, opt::Option::KIND##Class,       \
47    X8, X7, OPT_##GROUP, OPT_##ALIAS, X6},
48 #include "Options.inc"
49 #undef OPTION
50 };
51 
52 ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}
53 
54 // Parse -color-diagnostics={auto,always,never} or -no-color-diagnostics.
55 static bool getColorDiagnostics(opt::InputArgList &Args) {
56   bool Default = (ErrorOS == &errs() && Process::StandardErrHasColors());
57 
58   auto *Arg = Args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
59                               OPT_no_color_diagnostics);
60   if (!Arg)
61     return Default;
62   if (Arg->getOption().getID() == OPT_color_diagnostics)
63     return true;
64   if (Arg->getOption().getID() == OPT_no_color_diagnostics)
65     return false;
66 
67   StringRef S = Arg->getValue();
68   if (S == "auto")
69     return Default;
70   if (S == "always")
71     return true;
72   if (S != "never")
73     error("unknown option: -color-diagnostics=" + S);
74   return false;
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 // Parses a given list of options.
92 opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
93   // Make InputArgList from string vectors.
94   unsigned MissingIndex;
95   unsigned MissingCount;
96   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
97 
98   // We need to get the quoting style for response files before parsing all
99   // options so we parse here before and ignore all the options but
100   // --rsp-quoting.
101   opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
102 
103   // Expand response files (arguments in the form of @<filename>)
104   // and then parse the argument again.
105   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
106   Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
107 
108   // Interpret -color-diagnostics early so that error messages
109   // for unknown flags are colored.
110   Config->ColorDiagnostics = getColorDiagnostics(Args);
111   if (MissingCount)
112     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
113 
114   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
115     error("unknown argument: " + Arg->getSpelling());
116   return Args;
117 }
118 
119 void elf::printHelp(const char *Argv0) {
120   ELFOptTable Table;
121   Table.PrintHelp(outs(), Argv0, "lld", false);
122   outs() << "\n";
123 
124   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
125   // recent version as of March 2017) expect /: supported targets:.* elf/
126   // in a message for the -help option. If it doesn't match, the scripts
127   // assume that the linker doesn't support very basic features such as
128   // shared libraries. Therefore, we need to print out at least "elf".
129   // Here, we print out all the targets that we support.
130   outs() << Argv0 << ": supported targets: "
131          << "elf32-i386 elf32-iamcu elf32-littlearm elf32-powerpc "
132          << "elf32-tradbigmips elf32-tradlittlemips "
133          << "elf32-ntradbigmips elf32-ntradlittlemips elf32-x86-64 "
134          << "elf64-amdgpu elf64-littleaarch64 elf64-powerpc "
135          << "elf64-tradbigmips elf64-tradlittlemips elf64-x86-64\n";
136 }
137 
138 // Reconstructs command line arguments so that so that you can re-run
139 // the same command with the same inputs. This is for --reproduce.
140 std::string elf::createResponseFile(const opt::InputArgList &Args) {
141   SmallString<0> Data;
142   raw_svector_ostream OS(Data);
143 
144   // Copy the command line to the output while rewriting paths.
145   for (auto *Arg : Args) {
146     switch (Arg->getOption().getID()) {
147     case OPT_reproduce:
148       break;
149     case OPT_INPUT:
150       OS << quote(rewritePath(Arg->getValue())) << "\n";
151       break;
152     case OPT_o:
153       // If -o path contains directories, "lld @response.txt" will likely
154       // fail because the archive we are creating doesn't contain empty
155       // directories for the output path (-o doesn't create directories).
156       // Strip directories to prevent the issue.
157       OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
158       break;
159     case OPT_L:
160     case OPT_dynamic_list:
161     case OPT_rpath:
162     case OPT_alias_script_T:
163     case OPT_script:
164     case OPT_version_script:
165       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
166          << "\n";
167       break;
168     default:
169       OS << toString(Arg) << "\n";
170     }
171   }
172   return Data.str();
173 }
174 
175 // Find a file by concatenating given paths. If a resulting path
176 // starts with "=", the character is replaced with a --sysroot value.
177 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
178   SmallString<128> S;
179   if (Path1.startswith("="))
180     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
181   else
182     path::append(S, Path1, Path2);
183 
184   if (fs::exists(S))
185     return S.str().str();
186   return None;
187 }
188 
189 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
190   for (StringRef Dir : Config->SearchPaths)
191     if (Optional<std::string> S = findFile(Dir, Path))
192       return S;
193   return None;
194 }
195 
196 // This is for -lfoo. We'll look for libfoo.so or libfoo.a from
197 // search paths.
198 Optional<std::string> elf::searchLibrary(StringRef Name) {
199   if (Name.startswith(":"))
200     return findFromSearchPaths(Name.substr(1));
201 
202   for (StringRef Dir : Config->SearchPaths) {
203     if (!Config->Static)
204       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
205         return S;
206     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
207       return S;
208   }
209   return None;
210 }
211