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 "llvm/ADT/STLExtras.h"
19 #include "llvm/Support/CommandLine.h"
20 #include "llvm/Support/FileSystem.h"
21 #include "llvm/Support/Path.h"
22 #include "llvm/Support/StringSaver.h"
23 
24 using namespace llvm;
25 
26 using namespace lld;
27 using namespace lld::elf2;
28 
29 // Create OptTable
30 
31 // Create prefix string literals used in Options.td
32 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
33 #include "Options.inc"
34 #undef PREFIX
35 
36 // Create table mapping all options defined in Options.td
37 static const opt::OptTable::Info infoTable[] = {
38 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
39   {                                                                            \
40     X1, X2, X9, X10, OPT_##ID, opt::Option::KIND##Class, X8, X7, OPT_##GROUP,  \
41         OPT_##ALIAS, X6                                                        \
42   }                                                                            \
43   ,
44 #include "Options.inc"
45 #undef OPTION
46 };
47 
48 class ELFOptTable : public opt::OptTable {
49 public:
50   ELFOptTable() : OptTable(infoTable) {}
51 };
52 
53 // Parses a given list of options.
54 opt::InputArgList lld::elf2::parseArgs(llvm::BumpPtrAllocator *A,
55                                        ArrayRef<const char *> Argv) {
56   // Make InputArgList from string vectors.
57   ELFOptTable Table;
58   unsigned MissingIndex;
59   unsigned MissingCount;
60 
61   // Expand response files. '@<filename>' is replaced by the file's contents.
62   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
63   StringSaver Saver(*A);
64   llvm::cl::ExpandResponseFiles(Saver, llvm::cl::TokenizeGNUCommandLine, Vec);
65 
66   // Parse options and then do error checking.
67   opt::InputArgList Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
68   if (MissingCount)
69     error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
70           "\", expected " + Twine(MissingCount) +
71           (MissingCount == 1 ? " argument.\n" : " arguments"));
72 
73   iterator_range<opt::arg_iterator> Unknowns = Args.filtered(OPT_UNKNOWN);
74   for (auto *Arg : Unknowns)
75     warning("warning: unknown argument: " + Arg->getSpelling());
76   if (Unknowns.begin() != Unknowns.end())
77     error("unknown argument(s) found");
78 
79   return Args;
80 }
81 
82 std::string lld::elf2::findFromSearchPaths(StringRef Path) {
83   for (StringRef Dir : Config->SearchPaths) {
84     std::string FullPath = buildSysrootedPath(Dir, Path);
85     if (sys::fs::exists(FullPath))
86       return FullPath;
87   }
88   return "";
89 }
90 
91 // Searches a given library from input search paths, which are filled
92 // from -L command line switches. Returns a path to an existent library file.
93 std::string lld::elf2::searchLibrary(StringRef Path) {
94   std::vector<std::string> Names;
95   if (Path[0] == ':') {
96     Names.push_back(Path.drop_front());
97   } else {
98     if (!Config->Static)
99       Names.push_back(("lib" + Path + ".so").str());
100     Names.push_back(("lib" + Path + ".a").str());
101   }
102   for (const std::string &Name : Names) {
103     std::string S = findFromSearchPaths(Name);
104     if (!S.empty())
105       return S;
106   }
107   error("Unable to find library -l" + Path);
108 }
109 
110 // Makes a path by concatenating Dir and File.
111 // If Dir starts with '=' the result will be preceded by Sysroot,
112 // which can be set with --sysroot command line switch.
113 std::string lld::elf2::buildSysrootedPath(StringRef Dir, StringRef File) {
114   SmallString<128> Path;
115   if (Dir.startswith("="))
116     sys::path::append(Path, Config->Sysroot, Dir.substr(1), File);
117   else
118     sys::path::append(Path, Dir, File);
119   return Path.str();
120 }
121