Commit d2cd7c59 authored by Bill Wendling's avatar Bill Wendling
Browse files

Merging r216531: 

------------------------------------------------------------------------
r216531 | chandlerc | 2014-08-27 01:41:41 -0700 (Wed, 27 Aug 2014) | 22 lines

Significantly fix Clang's header search for Ubuntu (and possibly other
modern Debian-based distributions) due to on-going multiarch madness.

It appears that when the multiarch heeader search support went into the
clang driver, it went in in a quite bad state. The order of includes
completely failed to match the order exhibited by GCC, and in a specific
case -- when the GCC triple and the multiarch triple don't match as with
i686-linux-gnu and i386-linux-gnu -- we would absolutely fail to find
the libstdc++ target-specific header files.

I assume that folks who have been using Clang on Ubuntu 32-bit systems
have been applying weird patches to hack around this. I can't imagine
how else it could have worked. This was originally reported by a 64-bit
operating system user who had a 32-bit crosscompiler installed. We tried
to use that rather than the bi-arch support of the 64-bit compiler, but
failed due to the triple differences.

I've corrected all the wrong orderings in the existing tests and added
a specific test for the multiarch triple strings that are different in
a significant way. This should significantly improve the usability of
Clang when checked out vanilla from upstream onto Ubuntu machines with
an i686 GCC installation for whatever reason.
------------------------------------------------------------------------

llvm-svn: 216587
parent 76d25814

clang/lib/Driver/ToolChains.cpp

+40 −24
Original line number Diff line number Diff line
@@ -3386,32 +3386,39 @@ void Linux::AddClangSystemIncludeArgs(const ArgList &DriverArgs, 
  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");

}



/// \brief Helper to add the three variant paths for a libstdc++ installation.

/*static*/ bool Linux::addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,

                                                const ArgList &DriverArgs,

                                                ArgStringList &CC1Args) {

  if (!llvm::sys::fs::exists(Base))

    return false;

  addSystemInclude(DriverArgs, CC1Args, Base);

  addSystemInclude(DriverArgs, CC1Args, Base + "/" + TargetArchDir);

  addSystemInclude(DriverArgs, CC1Args, Base + "/backward");

  return true;

}



/// \brief Helper to add an extra variant path for an (Ubuntu) multilib

/// libstdc++ installation.

/// \brief Helper to add the variant paths of a libstdc++ installation.

/*static*/ bool Linux::addLibStdCXXIncludePaths(Twine Base, Twine Suffix,

                                                Twine TargetArchDir,

                                                StringRef GCCTriple,

                                                StringRef GCCMultiarchTriple,

                                                StringRef TargetMultiarchTriple,

                                                Twine IncludeSuffix,

                                                const ArgList &DriverArgs,

                                                ArgStringList &CC1Args) {

  if (!addLibStdCXXIncludePaths(Base + Suffix,

                                TargetArchDir + IncludeSuffix,

                                DriverArgs, CC1Args))

  if (!llvm::sys::fs::exists(Base))

    return false;



  addSystemInclude(DriverArgs, CC1Args, Base + "/" + TargetArchDir + Suffix

                   + IncludeSuffix);

  addSystemInclude(DriverArgs, CC1Args, Base + Suffix);



  // The vanilla GCC layout of libstdc++ headers uses a triple subdirectory. If

  // that path exists or we have neither a GCC nor target multiarch triple, use

  // this vanilla search path.

  if ((GCCMultiarchTriple.empty() && TargetMultiarchTriple.empty()) ||

      llvm::sys::fs::exists(Base + Suffix + "/" + GCCTriple + IncludeSuffix)) {

    addSystemInclude(DriverArgs, CC1Args,

                     Base + Suffix + "/" + GCCTriple + IncludeSuffix);

  } else {

    // Otherwise try to use multiarch naming schemes which have normalized the

    // triples and put the triple before the suffix.

    //

    // GCC surprisingly uses *both* the GCC triple with a multilib suffix and

    // the target triple, so we support that here.

    addSystemInclude(DriverArgs, CC1Args,

                     Base + "/" + GCCMultiarchTriple + Suffix + IncludeSuffix);

    addSystemInclude(DriverArgs, CC1Args,

                     Base + "/" + TargetMultiarchTriple + Suffix);

  }



  addSystemInclude(DriverArgs, CC1Args, Base + Suffix + "/backward");

  return true;

}
@@ -3455,13 +3462,21 @@ void Linux::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs, 
  StringRef InstallDir = GCCInstallation.getInstallPath();

  StringRef TripleStr = GCCInstallation.getTriple().str();

  const Multilib &Multilib = GCCInstallation.getMultilib();

  const std::string GCCMultiarchTriple =

      getMultiarchTriple(GCCInstallation.getTriple(), getDriver().SysRoot);

  const std::string TargetMultiarchTriple =

      getMultiarchTriple(getTriple(), getDriver().SysRoot);

  const GCCVersion &Version = GCCInstallation.getVersion();



  // The primary search for libstdc++ supports multiarch variants.

  if (addLibStdCXXIncludePaths(LibDir.str() + "/../include",

                               "/c++/" + Version.Text, TripleStr,

                               "/c++/" + Version.Text, TripleStr, GCCMultiarchTriple,

                               TargetMultiarchTriple,

                               Multilib.includeSuffix(), DriverArgs, CC1Args))

    return;



  // Otherwise, fall back on a bunch of options which don't use multiarch

  // layouts for simplicity.

  const std::string LibStdCXXIncludePathCandidates[] = {

    // Gentoo is weird and places its headers inside the GCC install, so if the

    // first attempt to find the headers fails, try these patterns.
@@ -3476,9 +3491,10 @@ void Linux::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs, 
  };



  for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {

    if (addLibStdCXXIncludePaths(IncludePath,

                                 TripleStr + Multilib.includeSuffix(),

                                 DriverArgs, CC1Args))

    if (addLibStdCXXIncludePaths(IncludePath, /*Suffix*/ "", TripleStr,

                                 /*GCCMultiarchTriple*/ "",

                                 /*TargetMultiarchTriple*/ "",

                                 Multilib.includeSuffix(), DriverArgs, CC1Args))

      break;

  }

}

clang/lib/Driver/ToolChains.h

+4 −4
Original line number Diff line number Diff line
@@ -678,10 +678,10 @@ protected: 


private:

  static bool addLibStdCXXIncludePaths(Twine Base, Twine Suffix,

                                       Twine TargetArchDir, Twine IncludeSuffix,

                                       const llvm::opt::ArgList &DriverArgs,

                                       llvm::opt::ArgStringList &CC1Args);

  static bool addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,

                                       StringRef GCCTriple,

                                       StringRef GCCMultiarchTriple,

                                       StringRef TargetMultiarchTriple,

                                       Twine IncludeSuffix,

                                       const llvm::opt::ArgList &DriverArgs,

                                       llvm::opt::ArgStringList &CC1Args);

clang/test/Driver/Inputs/ubuntu_14.04_multiarch_tree2/lib/i386-linux-gnu/.keep

0 → 100644
+0 −0

Empty file added.

clang/test/Driver/Inputs/ubuntu_14.04_multiarch_tree2/lib/x86_64-linux-gnu/.keep

0 → 100755
+0 −0

Empty file added.