1 //===--- Hurd.cpp - Hurd ToolChain Implementations --------*- C++ -*-===//
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 #include "Hurd.h"
10 #include "CommonArgs.h"
11 #include "clang/Config/config.h"
12 #include "clang/Driver/Driver.h"
13 #include "clang/Driver/Options.h"
14 #include "llvm/Support/Path.h"
15 #include "llvm/Support/VirtualFileSystem.h"
16 
17 using namespace clang::driver;
18 using namespace clang::driver::toolchains;
19 using namespace clang;
20 using namespace llvm::opt;
21 
22 using tools::addPathIfExists;
23 
24 /// Get our best guess at the multiarch triple for a target.
25 ///
26 /// Debian-based systems are starting to use a multiarch setup where they use
27 /// a target-triple directory in the library and header search paths.
28 /// Unfortunately, this triple does not align with the vanilla target triple,
29 /// so we provide a rough mapping here.
30 std::string Hurd::getMultiarchTriple(const Driver &D,
31                                      const llvm::Triple &TargetTriple,
32                                      StringRef SysRoot) const {
33   if (TargetTriple.getArch() == llvm::Triple::x86) {
34     // We use the existence of '/lib/<triple>' as a directory to detect some
35     // common hurd triples that don't quite match the Clang triple for both
36     // 32-bit and 64-bit targets. Multiarch fixes its install triples to these
37     // regardless of what the actual target triple is.
38     if (D.getVFS().exists(SysRoot + "/lib/i386-gnu"))
39       return "i386-gnu";
40   }
41 
42   // For most architectures, just use whatever we have rather than trying to be
43   // clever.
44   return TargetTriple.str();
45 }
46 
47 static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {
48   // It happens that only x86 and PPC use the 'lib32' variant of oslibdir, and
49   // using that variant while targeting other architectures causes problems
50   // because the libraries are laid out in shared system roots that can't cope
51   // with a 'lib32' library search path being considered. So we only enable
52   // them when we know we may need it.
53   //
54   // FIXME: This is a bit of a hack. We should really unify this code for
55   // reasoning about oslibdir spellings with the lib dir spellings in the
56   // GCCInstallationDetector, but that is a more significant refactoring.
57 
58   if (Triple.getArch() == llvm::Triple::x86)
59     return "lib32";
60 
61   return Triple.isArch32Bit() ? "lib" : "lib64";
62 }
63 
64 Hurd::Hurd(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
65     : Generic_ELF(D, Triple, Args) {
66   std::string SysRoot = computeSysRoot();
67   path_list &Paths = getFilePaths();
68 
69   const std::string OSLibDir = getOSLibDir(Triple, Args);
70   const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);
71 
72 #ifdef ENABLE_LINKER_BUILD_ID
73   ExtraOpts.push_back("--build-id");
74 #endif
75 
76   // If we are currently running Clang inside of the requested system root, add
77   // its parent library paths to those searched.
78   // FIXME: It's not clear whether we should use the driver's installed
79   // directory ('Dir' below) or the ResourceDir.
80   if (StringRef(D.Dir).startswith(SysRoot)) {
81     addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);
82     addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
83   }
84 
85   addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
86   addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
87 
88   addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
89   addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
90 
91   // If we are currently running Clang inside of the requested system root, add
92   // its parent library path to those searched.
93   // FIXME: It's not clear whether we should use the driver's installed
94   // directory ('Dir' below) or the ResourceDir.
95   if (StringRef(D.Dir).startswith(SysRoot))
96     addPathIfExists(D, D.Dir + "/../lib", Paths);
97 
98   addPathIfExists(D, SysRoot + "/lib", Paths);
99   addPathIfExists(D, SysRoot + "/usr/lib", Paths);
100 }
101 
102 bool Hurd::HasNativeLLVMSupport() const { return true; }
103 
104 Tool *Hurd::buildLinker() const { return new tools::gnutools::Linker(*this); }
105 
106 Tool *Hurd::buildAssembler() const {
107   return new tools::gnutools::Assembler(*this);
108 }
109 
110 std::string Hurd::computeSysRoot() const {
111   if (!getDriver().SysRoot.empty())
112     return getDriver().SysRoot;
113 
114   return std::string();
115 }
116 
117 std::string Hurd::getDynamicLinker(const ArgList &Args) const {
118   if (getArch() == llvm::Triple::x86)
119     return "/lib/ld.so";
120 
121   llvm_unreachable("unsupported architecture");
122 }
123 
124 void Hurd::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
125                                      ArgStringList &CC1Args) const {
126   const Driver &D = getDriver();
127   std::string SysRoot = computeSysRoot();
128 
129   if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
130     return;
131 
132   if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
133     addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");
134 
135   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
136     SmallString<128> P(D.ResourceDir);
137     llvm::sys::path::append(P, "include");
138     addSystemInclude(DriverArgs, CC1Args, P);
139   }
140 
141   if (DriverArgs.hasArg(options::OPT_nostdlibinc))
142     return;
143 
144   // Check for configure-time C include directories.
145   StringRef CIncludeDirs(C_INCLUDE_DIRS);
146   if (CIncludeDirs != "") {
147     SmallVector<StringRef, 5> Dirs;
148     CIncludeDirs.split(Dirs, ":");
149     for (StringRef Dir : Dirs) {
150       StringRef Prefix =
151           llvm::sys::path::is_absolute(Dir) ? StringRef(SysRoot) : "";
152       addExternCSystemInclude(DriverArgs, CC1Args, Prefix + Dir);
153     }
154     return;
155   }
156 
157   // Lacking those, try to detect the correct set of system includes for the
158   // target triple.
159   if (getTriple().getArch() == llvm::Triple::x86) {
160     std::string Path = SysRoot + "/usr/include/i386-gnu";
161     if (D.getVFS().exists(Path))
162       addExternCSystemInclude(DriverArgs, CC1Args, Path);
163   }
164 
165   // Add an include of '/include' directly. This isn't provided by default by
166   // system GCCs, but is often used with cross-compiling GCCs, and harmless to
167   // add even when Clang is acting as-if it were a system compiler.
168   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");
169 
170   addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");
171 }
172 
173 void Hurd::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {
174   for (const auto &Opt : ExtraOpts)
175     CmdArgs.push_back(Opt.c_str());
176 }
177