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 }
123 
124 // Reconstructs command line arguments so that so that you can re-run
125 // the same command with the same inputs. This is for --reproduce.
126 std::string elf::createResponseFile(const opt::InputArgList &Args) {
127   SmallString<0> Data;
128   raw_svector_ostream OS(Data);
129 
130   // Copy the command line to the output while rewriting paths.
131   for (auto *Arg : Args) {
132     switch (Arg->getOption().getID()) {
133     case OPT_reproduce:
134       break;
135     case OPT_INPUT:
136       OS << quote(rewritePath(Arg->getValue())) << "\n";
137       break;
138     case OPT_o:
139       // If -o path contains directories, "lld @response.txt" will likely
140       // fail because the archive we are creating doesn't contain empty
141       // directories for the output path (-o doesn't create directories).
142       // Strip directories to prevent the issue.
143       OS << "-o " << quote(sys::path::filename(Arg->getValue())) << "\n";
144       break;
145     case OPT_L:
146     case OPT_dynamic_list:
147     case OPT_rpath:
148     case OPT_alias_script_T:
149     case OPT_script:
150     case OPT_version_script:
151       OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
152          << "\n";
153       break;
154     default:
155       OS << toString(Arg) << "\n";
156     }
157   }
158   return Data.str();
159 }
160 
161 // Find a file by concatenating given paths. If a resulting path
162 // starts with "=", the character is replaced with a --sysroot value.
163 static Optional<std::string> findFile(StringRef Path1, const Twine &Path2) {
164   SmallString<128> S;
165   if (Path1.startswith("="))
166     path::append(S, Config->Sysroot, Path1.substr(1), Path2);
167   else
168     path::append(S, Path1, Path2);
169 
170   if (fs::exists(S))
171     return S.str().str();
172   return None;
173 }
174 
175 Optional<std::string> elf::findFromSearchPaths(StringRef Path) {
176   for (StringRef Dir : Config->SearchPaths)
177     if (Optional<std::string> S = findFile(Dir, Path))
178       return S;
179   return None;
180 }
181 
182 // This is for -lfoo. We'll look for libfoo.so or libfoo.a from
183 // search paths.
184 Optional<std::string> elf::searchLibrary(StringRef Name) {
185   if (Name.startswith(":"))
186     return findFromSearchPaths(Name.substr(1));
187 
188   for (StringRef Dir : Config->SearchPaths) {
189     if (!Config->Static)
190       if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".so"))
191         return S;
192     if (Optional<std::string> S = findFile(Dir, "lib" + Name + ".a"))
193       return S;
194   }
195   return None;
196 }
197