Detect Clear Linux and apply Clear's default linker options

[thiagomacieira]

Summary

/usr/lib/os-release is the official path of /etc/os-release (the latter is usually a symlink to the former)

[thiagomacieira]

Oops, add the missing portion of the unit test (the part that actually tests).

[mgorny]

lib/Driver/Distro.cpp

139

Technically speaking, the spec says you are supposed to read /etc/os-release first and fall back to /usr/lib/os-release only if the former does not exist.

[thiagomacieira]

lib/Driver/Distro.cpp

139

You're right, I'll adapt.

[thiagomacieira]

Updated to check for /etc/os-release first and /usr/lib/os-release if that fails

[thiagomacieira]

lib/Driver/Distro.cpp

148

I'm changing this so we can detect Clear-derived distributions.

[thiagomacieira]

Update detection: as of Clear Linux 25620, /usr/lib/os-relaese contains ID_LIKE=clear-linux-os, which allows detecting not only Clear itself, but also Linux distributions derived from it (Clear Linux mixes).

[mgorny]

LGTM, presuming the tests pass for you.

include/clang/Driver/Distro.h

 class Distro {
 public:
   enum DistroType {
     // NB: Releases of a particular Linux distro should be kept together
     // in this enum, because some tests are done by integer comparison against
     // the first and last known member in the family, e.g. IsRedHat().
     AlpineLinux,
     ArchLinux,
+    ClearLinux,
     DebianLenny,
     DebianSqueeze,
     DebianWheezy,
     DebianJessie,
     DebianStretch,
     DebianBuster,
     Exherbo,
     RHEL5,
public:
   bool IsUbuntu() const {
     return DistroVal >= UbuntuHardy && DistroVal <= UbuntuCosmic;
   }
 
   bool IsAlpineLinux() const {
     return DistroVal == AlpineLinux;
   }
 
+  bool IsClearLinux() const {
+    return DistroVal == ClearLinux;
+  }
+
   /// @}
 };
 
 } // end namespace driver
 } // end namespace clang
 
 #endif

lib/Driver/Distro.cpp

if (VFS.exists("/etc/exherbo-release"))
     return Distro::Exherbo;
 
   if (VFS.exists("/etc/alpine-release"))
     return Distro::AlpineLinux;
 
   if (VFS.exists("/etc/arch-release"))
     return Distro::ArchLinux;
 
+  File = VFS.getBufferForFile("/usr/lib/os-release");
+  if (File) {
+    StringRef Data = File.get()->getBuffer();
+    SmallVector<StringRef, 16> Lines;
+    Data.split(Lines, "\n");
+    Distro::DistroType Version = Distro::UnknownDistro;
+    for (StringRef Line : Lines)
+      if (Version == Distro::UnknownDistro && Line.startswith("ID="))
+        Version = llvm::StringSwitch<Distro::DistroType>(Line.substr(3))
+                      .Case("clear-linux-os", Distro::ClearLinux);
+    return Version;
+  }
+
   return Distro::UnknownDistro;
 }
 
 Distro::Distro(vfs::FileSystem &VFS) : DistroVal(DetectDistro(VFS)) {}

lib/Driver/ToolChains/Linux.cpp

Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
   // FIXME: This seems unlikely to be Linux-specific.
   ToolChain::path_list &PPaths = getProgramPaths();
   PPaths.push_back(Twine(GCCInstallation.getParentLibPath() + "/../" +
                          GCCInstallation.getTriple().str() + "/bin")
                        .str());
 
   Distro Distro(D.getVFS());
 
-  if (Distro.IsAlpineLinux()) {
+  if (Distro.IsAlpineLinux() || Distro.IsClearLinux()) {
     ExtraOpts.push_back("-z");
     ExtraOpts.push_back("now");
   }
 
-  if (Distro.IsOpenSUSE() || Distro.IsUbuntu() || Distro.IsAlpineLinux()) {
+  if (Distro.IsOpenSUSE() || Distro.IsUbuntu() || Distro.IsAlpineLinux() || Distro.IsClearLinux()) {
     ExtraOpts.push_back("-z");
     ExtraOpts.push_back("relro");
   }
 
+  if (Distro.IsClearLinux())
+    ExtraOpts.push_back("--copy-dt-needed-entries");
+
   if (GCCInstallation.getParentLibPath().find("opt/rh/devtoolset") !=
       StringRef::npos)
     // With devtoolset on RHEL, we want to add a bin directory that is relative
     // to the detected gcc install, because if we are using devtoolset gcc then
     // we want to use other tools from devtoolset (e.g. ld) instead of the
     // standard system tools.
     PPaths.push_back(Twine(GCCInstallation.getParentLibPath() +
                      "/../bin").str());
Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
 
   if (Distro.IsRedhat() && Distro != Distro::RHEL5 && Distro != Distro::RHEL6)
     ExtraOpts.push_back("--no-add-needed");
 
 #ifdef ENABLE_LINKER_BUILD_ID
   ExtraOpts.push_back("--build-id");
 #endif
 
-  if (IsAndroid || Distro.IsOpenSUSE())
+  if (IsAndroid || Distro.IsOpenSUSE() || Distro.IsClearLinux())
     ExtraOpts.push_back("--enable-new-dtags");
 
   // The selection of paths to try here is designed to match the patterns which
   // the GCC driver itself uses, as this is part of the GCC-compatible driver.
   // This was determined by running GCC in a fake filesystem, creating all
   // possible permutations of these directories, and seeing which ones it added
   // to the link paths.
   path_list &Paths = getFilePaths();

unittests/Driver/DistroTest.cpp

TEST(DistroTest, DetectArchLinux) {
   Distro ArchLinux{ArchLinuxFileSystem};
   ASSERT_EQ(Distro(Distro::ArchLinux), ArchLinux);
   ASSERT_FALSE(ArchLinux.IsUbuntu());
   ASSERT_FALSE(ArchLinux.IsRedhat());
   ASSERT_FALSE(ArchLinux.IsOpenSUSE());
   ASSERT_FALSE(ArchLinux.IsDebian());
 }
 
+TEST(DistroTest, DetectClearLinux) {
+  vfs::InMemoryFileSystem ClearLinuxFileSystem;
+  ClearLinuxFileSystem.addFile("/usr/lib/os-release", 0,
+      llvm::MemoryBuffer::getMemBuffer("NAME=\"Clear Linux OS\"\n"
+                                       "VERSION=1\n"
+                                       "ID=clear-linux-os\n"
+                                       "VERSION_ID=25530\n"
+                                       "PRETTY_NAME=\"Clear Linux OS\"\n"
+                                       "ANSI_COLOR=\"1;35\"\n"
+                                       "HOME_URL=\"https://clearlinux.org\"\n"
+                                       "SUPPORT_URL=\"https://clearlinux.org\"\n"
+                                       "BUG_REPORT_URL=\"mailto:[e-mail]\"\n"
+                                       "PRIVACY_POLICY_URL=\"http://www.intel.com/privacy\"\n"));
+}
+
 } // end anonymous namespace