sys-devel/llvm: Update llvm-config patches for improved compatibility

Backport upstream r252532 that improves llvm-config support for shared
libraries, adding --shared-mode option in particular, along with
--build-system option needed for it. Also fix --build-mode to report
"Release" rather than non-standard "Gentoo" type.

Bug: https://bugs.gentoo.org/show_bug.cgi?id=578304

5 files changed, 1237 insertions, 0 deletions

diff --git a/sys-devel/llvm/files/llvm-3.7.1-llvm-config-0.patch b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-0.patch
new file mode 100644
index 000000000000..87f9ff8c5ad7
--- /dev/null
+++ b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-0.patch
@@ -0,0 +1,83 @@
+From a59464503a7e059ddfd3fb4308753b692d03d996 Mon Sep 17 00:00:00 2001
+From: Tom Stellard <thomas.stellard@amd.com>
+Date: Wed, 9 Sep 2015 16:39:30 +0000
+Subject: [PATCH 1/4] llvm-config: Add --build-system option
+
+Summary:
+This can be used for distinguishing between cmake and autoconf builds.
+Users may need this in order to handle inconsistencies between the
+outputs of the two build systems.
+
+Reviewers: echristo, chandlerc, beanz
+
+Subscribers: llvm-commits
+
+Differential Revision: http://reviews.llvm.org/D11838
+
+git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247159 91177308-0d34-0410-b5e6-96231b3b80d8
+---
+ tools/llvm-config/BuildVariables.inc.in | 1 +
+ tools/llvm-config/CMakeLists.txt        | 2 ++
+ tools/llvm-config/Makefile              | 2 ++
+ tools/llvm-config/llvm-config.cpp       | 3 +++
+ 4 files changed, 8 insertions(+)
+
+diff --git a/tools/llvm-config/BuildVariables.inc.in b/tools/llvm-config/BuildVariables.inc.in
+index 3f51f49..0f28fad 100644
+--- a/tools/llvm-config/BuildVariables.inc.in
++++ b/tools/llvm-config/BuildVariables.inc.in
+@@ -26,3 +26,4 @@
+ #define LLVM_LIBDIR_SUFFIX "@LLVM_LIBDIR_SUFFIX@"
+ #define LLVM_TARGETS_BUILT "@LLVM_TARGETS_BUILT@"
+ #define LLVM_SYSTEM_LIBS "@LLVM_SYSTEM_LIBS@"
++#define LLVM_BUILD_SYSTEM "@LLVM_BUILD_SYSTEM@"
+diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt
+index edbd8c9..dd53460 100644
+--- a/tools/llvm-config/CMakeLists.txt
++++ b/tools/llvm-config/CMakeLists.txt
+@@ -24,6 +24,8 @@ set(LLVM_OBJ_ROOT ${LLVM_BINARY_DIR})
+ set(LLVM_CPPFLAGS "${CMAKE_CPP_FLAGS} ${CMAKE_CPP_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+ set(LLVM_CFLAGS "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+ set(LLVM_CXXFLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${COMPILE_FLAGS} ${LLVM_DEFINITIONS}")
++set(LLVM_BUILD_SYSTEM cmake)
++
+ # Use the C++ link flags, since they should be a superset of C link flags.
+ set(LLVM_LDFLAGS "${CMAKE_CXX_LINK_FLAGS}")
+ set(LLVM_BUILDMODE ${CMAKE_BUILD_TYPE})
+diff --git a/tools/llvm-config/Makefile b/tools/llvm-config/Makefile
+index 1ff8b6f..c2b5e8f 100644
+--- a/tools/llvm-config/Makefile
++++ b/tools/llvm-config/Makefile
+@@ -65,6 +65,8 @@ $(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile $(ObjDir)/.dir
+ 	  >> temp.sed
+ 	$(Verb) $(ECHO) 's/@LLVM_TARGETS_BUILT@/$(subst /,\/,$(TARGETS_TO_BUILD))/' \
+ 	  >> temp.sed
++	$(Verb) $(ECHO) 's/@LLVM_BUILD_SYSTEM@/autoconf/' \
++	  >> temp.sed
+ 	$(Verb) $(SED) -f temp.sed < $< > $@
+ 	$(Verb) $(RM) temp.sed
+ 
+diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
+index 879b9ab..4ce8f10 100644
+--- a/tools/llvm-config/llvm-config.cpp
++++ b/tools/llvm-config/llvm-config.cpp
+@@ -157,6 +157,7 @@ Options:\n\
+   --host-target     Target triple used to configure LLVM.\n\
+   --build-mode      Print build mode of LLVM tree (e.g. Debug or Release).\n\
+   --assertion-mode  Print assertion mode of LLVM tree (ON or OFF).\n\
++  --build-system    Print the build system used to build LLVM (autoconf or cmake).\n\
+ Typical components:\n\
+   all               All LLVM libraries (default).\n\
+   engine            Either a native JIT or a bitcode interpreter.\n";
+@@ -323,6 +324,8 @@ int main(int argc, char **argv) {
+ #else
+         OS << "ON\n";
+ #endif
++      } else if (Arg == "--build-system") {
++        OS << LLVM_BUILD_SYSTEM << '\n';
+       } else if (Arg == "--obj-root") {
+         OS << ActivePrefix << '\n';
+       } else if (Arg == "--src-root") {
+-- 
+2.7.4
+
diff --git a/sys-devel/llvm/files/llvm-3.7.1-llvm-config-1.patch b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-1.patch
new file mode 100644
index 000000000000..214a3bbbc0e2
--- /dev/null
+++ b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-1.patch
@@ -0,0 +1,453 @@
+From 55433193c56e6b2e0792c3ca1b0ef3881ab01138 Mon Sep 17 00:00:00 2001
+From: Richard Diamond <wichard@vitalitystudios.com>
+Date: Mon, 9 Nov 2015 23:15:38 +0000
+Subject: [PATCH 2/4] Fix `llvm-config` to adapt to the install environment.
+
+Summary:
+This patch does a couple of things:
+
+  - Adds a new argument `--shared-mode` which accepts a list of components and prints whether or not the provided components need to be linked statically or shared.
+  - Fixes `--libnames` when CMake BUILD_SHARED_LIBS is used.
+  - Fixes `--libnames`, `--libs`, and `--libfiles` for dylib when static components aren't installed.
+  - Fixes `--libnames`, `--libs`, `--libfiles`, and `--components` to use LLVM_DYLIB_COMPONENTS as the component manifest for dylib linking.
+  - Uses the host platform's usual convention for filename extensions and such, instead of always defaulting to Unix-izms.
+
+Because I don't own a Mac, I am not able to test the Mac platform dependent stuff locally. If someone would be willing to run a build for me on their machine (unless there's a better option), I'd appreciate it.
+
+Reviewers: jfb, brad.king, whitequark, beanz
+
+Subscribers: beanz, jauhien, llvm-commits
+
+Differential Revision: http://reviews.llvm.org/D13198
+
+git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252532 91177308-0d34-0410-b5e6-96231b3b80d8
+---
+ bindings/ocaml/Makefile.ocaml           |   2 +
+ tools/llvm-config/BuildVariables.inc.in |   3 +
+ tools/llvm-config/CMakeLists.txt        |   5 +
+ tools/llvm-config/llvm-config.cpp       | 265 +++++++++++++++++++++++++++++---
+ 4 files changed, 253 insertions(+), 22 deletions(-)
+
+diff --git a/bindings/ocaml/Makefile.ocaml b/bindings/ocaml/Makefile.ocaml
+index 1f65a7b..22b96a2 100644
+--- a/bindings/ocaml/Makefile.ocaml
++++ b/bindings/ocaml/Makefile.ocaml
+@@ -277,6 +277,8 @@ uninstall-local:: uninstall-deplibs
+ 
+ build-deplibs: $(OutputLibs)
+ 
++$(OcamlDir)/%.so: $(LibDir)/%.so
++	$(Verb) ln -sf $< $@
+ $(OcamlDir)/%.a: $(LibDir)/%.a
+ 	$(Verb) ln -sf $< $@
+ 
+diff --git a/tools/llvm-config/BuildVariables.inc.in b/tools/llvm-config/BuildVariables.inc.in
+index 0f28fad..e384838 100644
+--- a/tools/llvm-config/BuildVariables.inc.in
++++ b/tools/llvm-config/BuildVariables.inc.in
+@@ -27,3 +27,6 @@
+ #define LLVM_TARGETS_BUILT "@LLVM_TARGETS_BUILT@"
+ #define LLVM_SYSTEM_LIBS "@LLVM_SYSTEM_LIBS@"
+ #define LLVM_BUILD_SYSTEM "@LLVM_BUILD_SYSTEM@"
++#define LLVM_ENABLE_DYLIB "@LLVM_BUILD_LLVM_DYLIB@"
++#define LLVM_ENABLE_SHARED "@LLVM_ENABLE_SHARED@"
++#define LLVM_DYLIB_COMPONENTS "@LLVM_DYLIB_COMPONENTS@"
+diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt
+index dd53460..173f6dc 100644
+--- a/tools/llvm-config/CMakeLists.txt
++++ b/tools/llvm-config/CMakeLists.txt
+@@ -30,6 +30,11 @@ set(LLVM_BUILD_SYSTEM cmake)
+ set(LLVM_LDFLAGS "${CMAKE_CXX_LINK_FLAGS}")
+ set(LLVM_BUILDMODE ${CMAKE_BUILD_TYPE})
+ set(LLVM_SYSTEM_LIBS ${SYSTEM_LIBS})
++if(BUILD_SHARED_LIBS)
++  set(LLVM_ENABLE_SHARED ON)
++else()
++  set(LLVM_ENABLE_SHARED OFF)
++endif()
+ string(REPLACE ";" " " LLVM_TARGETS_BUILT "${LLVM_TARGETS_TO_BUILD}")
+ configure_file(${BUILDVARIABLES_SRCPATH} ${BUILDVARIABLES_OBJPATH} @ONLY)
+ 
+diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
+index 4ce8f10..51efbd8 100644
+--- a/tools/llvm-config/llvm-config.cpp
++++ b/tools/llvm-config/llvm-config.cpp
+@@ -30,6 +30,7 @@
+ #include <cstdlib>
+ #include <set>
+ #include <vector>
++#include <unordered_set>
+ 
+ using namespace llvm;
+ 
+@@ -51,12 +52,16 @@ using namespace llvm;
+ /// \param Name - The component to traverse.
+ /// \param ComponentMap - A prebuilt map of component names to descriptors.
+ /// \param VisitedComponents [in] [out] - The set of already visited components.
+-/// \param RequiredLibs [out] - The ordered list of required libraries.
++/// \param RequiredLibs [out] - The ordered list of required
++/// libraries.
++/// \param GetComponentNames - Get the component names instead of the
++/// library name.
+ static void VisitComponent(StringRef Name,
+                            const StringMap<AvailableComponent*> &ComponentMap,
+                            std::set<AvailableComponent*> &VisitedComponents,
+                            std::vector<StringRef> &RequiredLibs,
+-                           bool IncludeNonInstalled) {
++                           bool IncludeNonInstalled, bool GetComponentNames,
++                           const std::string *ActiveLibDir, bool *HasMissing) {
+   // Lookup the component.
+   AvailableComponent *AC = ComponentMap.lookup(Name);
+   assert(AC && "Invalid component name!");
+@@ -74,12 +79,22 @@ static void VisitComponent(StringRef Name,
+   // Otherwise, visit all the dependencies.
+   for (unsigned i = 0; AC->RequiredLibraries[i]; ++i) {
+     VisitComponent(AC->RequiredLibraries[i], ComponentMap, VisitedComponents,
+-                   RequiredLibs, IncludeNonInstalled);
++                   RequiredLibs, IncludeNonInstalled, GetComponentNames,
++                   ActiveLibDir, HasMissing);
++  }
++
++  if (GetComponentNames) {
++    RequiredLibs.push_back(Name);
++    return;
+   }
+ 
+   // Add to the required library list.
+-  if (AC->Library)
++  if (AC->Library) {
++    if (!IncludeNonInstalled && HasMissing && !*HasMissing && ActiveLibDir) {
++      *HasMissing = !sys::fs::exists(*ActiveLibDir + "/" + AC->Library);
++    }
+     RequiredLibs.push_back(AC->Library);
++  }
+ }
+ 
+ /// \brief Compute the list of required libraries for a given list of
+@@ -91,9 +106,12 @@ static void VisitComponent(StringRef Name,
+ /// are required to link the given components.
+ /// \param IncludeNonInstalled - Whether non-installed components should be
+ /// reported.
++/// \param GetComponentNames - True if one would prefer the component names.
+ static void ComputeLibsForComponents(const std::vector<StringRef> &Components,
+                                      std::vector<StringRef> &RequiredLibs,
+-                                     bool IncludeNonInstalled) {
++                                     bool IncludeNonInstalled, bool GetComponentNames,
++                                     const std::string *ActiveLibDir,
++                                     bool *HasMissing) {
+   std::set<AvailableComponent*> VisitedComponents;
+ 
+   // Build a map of component names to information.
+@@ -116,7 +134,8 @@ static void ComputeLibsForComponents(const std::vector<StringRef> &Components,
+     }
+ 
+     VisitComponent(ComponentLower, ComponentMap, VisitedComponents,
+-                   RequiredLibs, IncludeNonInstalled);
++                   RequiredLibs, IncludeNonInstalled, GetComponentNames,
++                   ActiveLibDir, HasMissing);
+   }
+ 
+   // The list is now ordered with leafs first, we want the libraries to printed
+@@ -157,6 +176,7 @@ Options:\n\
+   --host-target     Target triple used to configure LLVM.\n\
+   --build-mode      Print build mode of LLVM tree (e.g. Debug or Release).\n\
+   --assertion-mode  Print assertion mode of LLVM tree (ON or OFF).\n\
++  --shared-mode     Print how the provided components can be collectively linked (`shared` or `static`).\n\
+   --build-system    Print the build system used to build LLVM (autoconf or cmake).\n\
+ Typical components:\n\
+   all               All LLVM libraries (default).\n\
+@@ -172,10 +192,38 @@ std::string GetExecutablePath(const char *Argv0) {
+   return llvm::sys::fs::getMainExecutable(Argv0, P);
+ }
+ 
++/// \brief Expand the semi-colon delimited LLVM_DYLIB_COMPONENTS into
++/// the full list of components.
++std::vector<StringRef> GetAllDyLibComponents(const bool IsInDevelopmentTree,
++                                             const bool GetComponentNames) {
++  std::vector<StringRef> DyLibComponents;
++  {
++    StringRef DyLibComponentsStr(LLVM_DYLIB_COMPONENTS);
++    size_t Offset = 0;
++    while (true) {
++      const size_t NextOffset = DyLibComponentsStr.find(';', Offset);
++      DyLibComponents.push_back(DyLibComponentsStr.substr(Offset, NextOffset));
++      if (NextOffset == std::string::npos) {
++        break;
++      }
++      Offset = NextOffset + 1;
++    }
++
++    assert(DyLibComponents.size() > 0);
++  }
++
++  std::vector<StringRef> Components;
++  ComputeLibsForComponents(DyLibComponents, Components,
++                           /*IncludeNonInstalled=*/IsInDevelopmentTree,
++                           GetComponentNames, nullptr, nullptr);
++
++  return std::move(Components);
++}
++
+ int main(int argc, char **argv) {
+   std::vector<StringRef> Components;
+   bool PrintLibs = false, PrintLibNames = false, PrintLibFiles = false;
+-  bool PrintSystemLibs = false;
++  bool PrintSystemLibs = false, PrintSharedMode = false;
+   bool HasAnyOption = false;
+ 
+   // llvm-config is designed to support being run both from a development tree
+@@ -270,6 +318,108 @@ int main(int argc, char **argv) {
+     ActiveIncludeOption = "-I" + ActiveIncludeDir;
+   }
+ 
++  /// We only use `shared library` mode in cases where the static library form
++  /// of the components provided are not available; note however that this is
++  /// skipped if we're run from within the build dir. However, once installed,
++  /// we still need to provide correct output when the static archives are
++  /// removed or, as in the case of CMake's `BUILD_SHARED_LIBS`, never present
++  /// in the first place. This can't be done at configure/build time.
++
++  StringRef SharedExt, SharedVersionedExt, SharedDir, SharedPrefix, StaticExt,
++    StaticPrefix, StaticDir = "lib";
++  const Triple HostTriple(Triple::normalize(LLVM_DEFAULT_TARGET_TRIPLE));
++  if (HostTriple.isOSWindows()) {
++    SharedExt = "dll";
++    SharedVersionedExt = PACKAGE_VERSION ".dll";
++    StaticExt = "a";
++    SharedDir = ActiveBinDir;
++    StaticDir = ActiveLibDir;
++    StaticPrefix = SharedPrefix = "";
++  } else if (HostTriple.isOSDarwin()) {
++    SharedExt = "dylib";
++    SharedVersionedExt = PACKAGE_VERSION ".dylib";
++    StaticExt = "a";
++    StaticDir = SharedDir = ActiveLibDir;
++    StaticPrefix = SharedPrefix = "lib";
++  } else {
++    // default to the unix values:
++    SharedExt = "so";
++    SharedVersionedExt = PACKAGE_VERSION ".so";
++    StaticExt = "a";
++    StaticDir = SharedDir = ActiveLibDir;
++    StaticPrefix = SharedPrefix = "lib";
++  }
++
++  const bool BuiltDyLib = (std::strcmp(LLVM_ENABLE_DYLIB, "ON") == 0);
++
++  enum { CMake, AutoConf } ConfigTool;
++  if (std::strcmp(LLVM_BUILD_SYSTEM, "cmake") == 0) {
++    ConfigTool = CMake;
++  } else {
++    ConfigTool = AutoConf;
++  }
++
++  /// CMake style shared libs, ie each component is in a shared library.
++  const bool BuiltSharedLibs =
++      (ConfigTool == CMake && std::strcmp(LLVM_ENABLE_SHARED, "ON") == 0);
++
++  bool DyLibExists = false;
++  const std::string DyLibName =
++    (SharedPrefix + "LLVM-" + SharedVersionedExt).str();
++
++  if (BuiltDyLib) {
++    DyLibExists = sys::fs::exists(SharedDir + "/" + DyLibName);
++  }
++
++  /// Get the component's library name without the lib prefix and the
++  /// extension. Returns true if Lib is in a recognized format.
++  auto GetComponentLibraryNameSlice = [&](const StringRef &Lib,
++                                          StringRef &Out) {
++    if (Lib.startswith("lib")) {
++      unsigned FromEnd;
++      if (Lib.endswith(StaticExt)) {
++        FromEnd = StaticExt.size() + 1;
++      } else if (Lib.endswith(SharedExt)) {
++        FromEnd = SharedExt.size() + 1;
++      } else {
++        FromEnd = 0;
++      }
++
++      if (FromEnd != 0) {
++        Out = Lib.slice(3, Lib.size() - FromEnd);
++        return true;
++      }
++    }
++
++    return false;
++  };
++  /// Maps Unixizms to the host platform.
++  auto GetComponentLibraryFileName = [&](const StringRef &Lib,
++                                         const bool ForceShared) {
++    std::string LibFileName = Lib;
++    StringRef LibName;
++    if (GetComponentLibraryNameSlice(Lib, LibName)) {
++      if (BuiltSharedLibs || ForceShared) {
++        LibFileName = (SharedPrefix + LibName + "." + SharedExt).str();
++      } else {
++        // default to static
++        LibFileName = (StaticPrefix + LibName + "." + StaticExt).str();
++      }
++    }
++
++    return LibFileName;
++  };
++  /// Get the full path for a possibly shared component library.
++  auto GetComponentLibraryPath = [&](const StringRef &Name,
++                                     const bool ForceShared) {
++    auto LibFileName = GetComponentLibraryFileName(Name, ForceShared);
++    if (BuiltSharedLibs || ForceShared) {
++      return (SharedDir + "/" + LibFileName).str();
++    } else {
++      return (StaticDir + "/" + LibFileName).str();
++    }
++  };
++
+   raw_ostream &OS = outs();
+   for (int i = 1; i != argc; ++i) {
+     StringRef Arg = argv[i];
+@@ -303,13 +453,33 @@ int main(int argc, char **argv) {
+       } else if (Arg == "--libfiles") {
+         PrintLibFiles = true;
+       } else if (Arg == "--components") {
++        /// If there are missing static archives and a dylib was
++        /// built, print LLVM_DYLIB_COMPONENTS instead of everything
++        /// in the manifest.
++        std::vector<StringRef> Components;
+         for (unsigned j = 0; j != array_lengthof(AvailableComponents); ++j) {
+           // Only include non-installed components when in a development tree.
+           if (!AvailableComponents[j].IsInstalled && !IsInDevelopmentTree)
+             continue;
+ 
+-          OS << ' ';
+-          OS << AvailableComponents[j].Name;
++          Components.push_back(AvailableComponents[j].Name);
++          if (AvailableComponents[j].Library && !IsInDevelopmentTree) {
++            if (DyLibExists &&
++                !sys::fs::exists(GetComponentLibraryPath(
++                    AvailableComponents[j].Library, false))) {
++              Components = GetAllDyLibComponents(IsInDevelopmentTree, true);
++              std::sort(Components.begin(), Components.end());
++              break;
++            }
++          }
++        }
++
++        for (unsigned I = 0; I < Components.size(); ++I) {
++          if (I) {
++            OS << ' ';
++          }
++
++          OS << Components[I];
+         }
+         OS << '\n';
+       } else if (Arg == "--targets-built") {
+@@ -324,6 +494,8 @@ int main(int argc, char **argv) {
+ #else
+         OS << "ON\n";
+ #endif
++      } else if (Arg == "--shared-mode") {
++        PrintSharedMode = true;
+       } else if (Arg == "--build-system") {
+         OS << LLVM_BUILD_SYSTEM << '\n';
+       } else if (Arg == "--obj-root") {
+@@ -341,35 +513,84 @@ int main(int argc, char **argv) {
+   if (!HasAnyOption)
+     usage();
+ 
+-  if (PrintLibs || PrintLibNames || PrintLibFiles || PrintSystemLibs) {
++  if (PrintLibs || PrintLibNames || PrintLibFiles || PrintSystemLibs ||
++      PrintSharedMode) {
++
++    if (PrintSharedMode && BuiltSharedLibs) {
++      OS << "shared\n";
++      return 0;
++    }
++
+     // If no components were specified, default to "all".
+     if (Components.empty())
+       Components.push_back("all");
+ 
+     // Construct the list of all the required libraries.
+     std::vector<StringRef> RequiredLibs;
++    bool HasMissing = false;
+     ComputeLibsForComponents(Components, RequiredLibs,
+-                             /*IncludeNonInstalled=*/IsInDevelopmentTree);
++                             /*IncludeNonInstalled=*/IsInDevelopmentTree, false,
++                             &ActiveLibDir, &HasMissing);
++
++    if (PrintSharedMode) {
++      std::unordered_set<std::string> FullDyLibComponents;
++      std::vector<StringRef> DyLibComponents =
++          GetAllDyLibComponents(IsInDevelopmentTree, false);
++
++      for (auto &Component : DyLibComponents) {
++        FullDyLibComponents.insert(Component);
++      }
++      DyLibComponents.clear();
++
++      for (auto &Lib : RequiredLibs) {
++        if (!FullDyLibComponents.count(Lib)) {
++          OS << "static\n";
++          return 0;
++        }
++      }
++      FullDyLibComponents.clear();
++
++      if (HasMissing && DyLibExists) {
++        OS << "shared\n";
++        return 0;
++      } else {
++        OS << "static\n";
++        return 0;
++      }
++    }
+ 
+     if (PrintLibs || PrintLibNames || PrintLibFiles) {
+-      for (unsigned i = 0, e = RequiredLibs.size(); i != e; ++i) {
+-        StringRef Lib = RequiredLibs[i];
+-        if (i)
+-          OS << ' ';
+ 
++      auto PrintForLib = [&](const StringRef &Lib, const bool ForceShared) {
+         if (PrintLibNames) {
+-          OS << Lib;
++          OS << GetComponentLibraryFileName(Lib, ForceShared);
+         } else if (PrintLibFiles) {
+-          OS << ActiveLibDir << '/' << Lib;
++          OS << GetComponentLibraryPath(Lib, ForceShared);
+         } else if (PrintLibs) {
+           // If this is a typical library name, include it using -l.
+-          if (Lib.startswith("lib") && Lib.endswith(".a")) {
+-            OS << "-l" << Lib.slice(3, Lib.size()-2);
+-            continue;
++          StringRef LibName;
++          if (Lib.startswith("lib")) {
++            if (GetComponentLibraryNameSlice(Lib, LibName)) {
++              OS << "-l" << LibName;
++            } else {
++              OS << "-l:" << GetComponentLibraryFileName(Lib, ForceShared);
++            }
++          } else {
++            // Otherwise, print the full path.
++            OS << GetComponentLibraryPath(Lib, ForceShared);
+           }
++        }
++      };
++
++      if (HasMissing && DyLibExists) {
++        PrintForLib(DyLibName, true);
++      } else {
++        for (unsigned i = 0, e = RequiredLibs.size(); i != e; ++i) {
++          StringRef Lib = RequiredLibs[i];
++          if (i)
++            OS << ' ';
+ 
+-          // Otherwise, print the full path.
+-          OS << ActiveLibDir << '/' << Lib;
++          PrintForLib(Lib, false);
+         }
+       }
+       OS << '\n';
+-- 
+2.7.4
+
diff --git a/sys-devel/llvm/files/llvm-3.7.1-llvm-config-2.patch b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-2.patch
new file mode 100644
index 000000000000..2895d38d7a2c
--- /dev/null
+++ b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-2.patch
@@ -0,0 +1,113 @@
+From 4abc261d14c886c21d24f639293a60ce45c1dca3 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Micha=C5=82=20G=C3=B3rny?= <mgorny@gentoo.org>
+Date: Wed, 2 Dec 2015 16:04:56 +0100
+Subject: [PATCH 3/4] llvm-config: Clean up exported values, update for shared
+ linking
+
+Gentoo-specific fixup for llvm-config, including:
+- wiping build-specific CFLAGS, CXXFLAGS,
+- updating library suffixes for shared libs,
+- wiping --system-libs for shared linking,
+- banning --obj-root and --src-root due to no sources installed,
+- making --build-mode return "Release" rather than "Gentoo".
+
+Thanks to Steven Newbury for the initial patch.
+
+Bug: https://bugs.gentoo.org/565358
+Bug: https://bugs.gentoo.org/501684
+---
+ tools/llvm-config/CMakeLists.txt   | 11 ++++++++---
+ tools/llvm-config/llvm-config.cpp  | 20 +++++++++++++++-----
+ utils/llvm-build/llvmbuild/main.py |  4 +++-
+ 3 files changed, 26 insertions(+), 9 deletions(-)
+
+diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt
+index 173f6dc..013ea8c 100644
+--- a/tools/llvm-config/CMakeLists.txt
++++ b/tools/llvm-config/CMakeLists.txt
+@@ -22,14 +22,19 @@ get_property(COMPILE_FLAGS TARGET llvm-config PROPERTY COMPILE_FLAGS)
+ set(LLVM_SRC_ROOT ${LLVM_MAIN_SRC_DIR})
+ set(LLVM_OBJ_ROOT ${LLVM_BINARY_DIR})
+ set(LLVM_CPPFLAGS "${CMAKE_CPP_FLAGS} ${CMAKE_CPP_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+-set(LLVM_CFLAGS "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+-set(LLVM_CXXFLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${COMPILE_FLAGS} ${LLVM_DEFINITIONS}")
++# Just use CMAKE_CPP_FLAGS for CFLAGS and CXXFLAGS, otherwise compiler
++# specific flags will be set when we don't know what compiler will be used
++# with external project utilising llvm-config.  C++ Standard is required.
++# TODO: figure out if we can remove -std=c++11 and move it to revdeps.
++set(LLVM_CFLAGS "${CMAKE_CPP_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
++set(LLVM_CXXFLAGS "${CMAKE_CPP_FLAGS} -std=c++11 ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+ set(LLVM_BUILD_SYSTEM cmake)
+ 
+ # Use the C++ link flags, since they should be a superset of C link flags.
+ set(LLVM_LDFLAGS "${CMAKE_CXX_LINK_FLAGS}")
+ set(LLVM_BUILDMODE ${CMAKE_BUILD_TYPE})
+-set(LLVM_SYSTEM_LIBS ${SYSTEM_LIBS})
++# We don't do static libs, so we don't need to supply any system-libs
++set(LLVM_SYSTEM_LIBS "")
+ if(BUILD_SHARED_LIBS)
+   set(LLVM_ENABLE_SHARED ON)
+ else()
+diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
+index 51efbd8..315e5e1 100644
+--- a/tools/llvm-config/llvm-config.cpp
++++ b/tools/llvm-config/llvm-config.cpp
+@@ -487,7 +487,8 @@ int main(int argc, char **argv) {
+       } else if (Arg == "--host-target") {
+         OS << Triple::normalize(LLVM_DEFAULT_TARGET_TRIPLE) << '\n';
+       } else if (Arg == "--build-mode") {
+-        OS << build_mode << '\n';
++        // force Release since we force non-standard Gentoo build mode
++        OS << "Release" << '\n';
+       } else if (Arg == "--assertion-mode") {
+ #if defined(NDEBUG)
+         OS << "OFF\n";
+@@ -498,10 +499,19 @@ int main(int argc, char **argv) {
+         PrintSharedMode = true;
+       } else if (Arg == "--build-system") {
+         OS << LLVM_BUILD_SYSTEM << '\n';
+-      } else if (Arg == "--obj-root") {
+-        OS << ActivePrefix << '\n';
+-      } else if (Arg == "--src-root") {
+-        OS << LLVM_SRC_ROOT << '\n';
++      } else if (Arg == "--obj-root" || Arg == "--src-root") {
++        if (IsInDevelopmentTree) {
++          if (Arg == "--obj-root") {
++            OS << ActivePrefix << '\n';
++          } else {
++            OS << LLVM_SRC_ROOT << '\n';
++          }
++        } else {
++          // sources are not installed
++          llvm::errs() << "llvm-config: sources not installed, "
++                       << Arg << " not available\n";
++          exit(1);
++        }
+       } else {
+         usage();
+       }
+diff --git a/utils/llvm-build/llvmbuild/main.py b/utils/llvm-build/llvmbuild/main.py
+index 353741f..4ba5e91 100644
+--- a/utils/llvm-build/llvmbuild/main.py
++++ b/utils/llvm-build/llvmbuild/main.py
+@@ -393,6 +393,8 @@ subdirectories = %s
+ //
+ //===----------------------------------------------------------------------===//
+ 
++#include "llvm/Config/config.h"
++
+ """)
+         f.write('struct AvailableComponent {\n')
+         f.write('  /// The name of the component.\n')
+@@ -413,7 +415,7 @@ subdirectories = %s
+             if library_name is None:
+                 library_name_as_cstr = '0'
+             else:
+-                library_name_as_cstr = '"lib%s.a"' % library_name
++                library_name_as_cstr = '"lib%s" LTDL_SHLIB_EXT' % library_name
+             f.write('  { "%s", %s, %d, { %s } },\n' % (
+                 name, library_name_as_cstr, is_installed,
+                 ', '.join('"%s"' % dep
+-- 
+2.7.4
+
diff --git a/sys-devel/llvm/files/llvm-3.7.1-llvm-config-3.patch b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-3.patch
new file mode 100644
index 000000000000..7a1547e255dc
--- /dev/null
+++ b/sys-devel/llvm/files/llvm-3.7.1-llvm-config-3.patch
@@ -0,0 +1,29 @@
+From 9308d1858852bdc6f099025ca0482d7b3a32a9aa Mon Sep 17 00:00:00 2001
+From: NAKAMURA Takumi <geek4civic@gmail.com>
+Date: Wed, 10 Feb 2016 01:12:55 +0000
+Subject: [PATCH 4/4] llvm-config: Quick fix for cross compilation. Don't be
+ confsed between host and target. It has been there since r252532.
+
+FIXME: The clause may use conditions of host compiler, not HOST_TRIPLE.
+
+git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260343 91177308-0d34-0410-b5e6-96231b3b80d8
+---
+ tools/llvm-config/llvm-config.cpp | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
+index 315e5e1..346c9d9 100644
+--- a/tools/llvm-config/llvm-config.cpp
++++ b/tools/llvm-config/llvm-config.cpp
+@@ -327,7 +327,7 @@ int main(int argc, char **argv) {
+ 
+   StringRef SharedExt, SharedVersionedExt, SharedDir, SharedPrefix, StaticExt,
+     StaticPrefix, StaticDir = "lib";
+-  const Triple HostTriple(Triple::normalize(LLVM_DEFAULT_TARGET_TRIPLE));
++  const Triple HostTriple(Triple::normalize(LLVM_HOST_TRIPLE));
+   if (HostTriple.isOSWindows()) {
+     SharedExt = "dll";
+     SharedVersionedExt = PACKAGE_VERSION ".dll";
+-- 
+2.7.4
+
diff --git a/sys-devel/llvm/llvm-3.7.1-r1.ebuild b/sys-devel/llvm/llvm-3.7.1-r1.ebuild
new file mode 100644
index 000000000000..5ae3bc64414c
--- /dev/null
+++ b/sys-devel/llvm/llvm-3.7.1-r1.ebuild
@@ -0,0 +1,559 @@
+# Copyright 1999-2016 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Id$
+
+EAPI=5
+
+: ${CMAKE_MAKEFILE_GENERATOR:=ninja}
+PYTHON_COMPAT=( python2_7 )
+
+inherit check-reqs cmake-utils eutils flag-o-matic multilib \
+	multilib-minimal python-single-r1 toolchain-funcs pax-utils prefix
+
+DESCRIPTION="Low Level Virtual Machine"
+HOMEPAGE="http://llvm.org/"
+SRC_URI="http://llvm.org/releases/${PV}/${P}.src.tar.xz
+	clang? ( http://llvm.org/releases/${PV}/compiler-rt-${PV}.src.tar.xz
+		http://llvm.org/releases/${PV}/cfe-${PV}.src.tar.xz
+		http://llvm.org/releases/${PV}/clang-tools-extra-${PV}.src.tar.xz )
+	lldb? ( http://llvm.org/releases/${PV}/lldb-${PV}.src.tar.xz )
+	!doc? ( http://dev.gentoo.org/~voyageur/distfiles/${PN}-3.7.0-manpages.tar.bz2 )"
+
+LICENSE="UoI-NCSA"
+SLOT="0/${PV}"
+KEYWORDS="~amd64 ~arm ~arm64 ~ppc ~ppc64 ~sparc ~x86 ~amd64-fbsd ~x86-fbsd ~x64-freebsd ~amd64-linux ~arm-linux ~x86-linux ~ppc-macos ~x64-macos ~x86-macos"
+IUSE="clang debug doc gold libedit +libffi lldb multitarget ncurses ocaml
+	python +static-analyzer test xml video_cards_radeon
+	kernel_Darwin kernel_FreeBSD"
+
+COMMON_DEPEND="
+	sys-libs/zlib:0=
+	clang? (
+		python? ( ${PYTHON_DEPS} )
+		static-analyzer? (
+			dev-lang/perl:*
+			${PYTHON_DEPS}
+		)
+		xml? ( dev-libs/libxml2:2=[${MULTILIB_USEDEP}] )
+	)
+	gold? ( >=sys-devel/binutils-2.22:*[cxx] )
+	libedit? ( dev-libs/libedit:0=[${MULTILIB_USEDEP}] )
+	libffi? ( >=virtual/libffi-3.0.13-r1:0=[${MULTILIB_USEDEP}] )
+	ncurses? ( >=sys-libs/ncurses-5.9-r3:0=[${MULTILIB_USEDEP}] )
+	ocaml? (
+		>=dev-lang/ocaml-4.00.0:0=
+		dev-ml/findlib
+		dev-ml/ocaml-ctypes
+		!!<=sys-devel/llvm-3.7.0-r1[ocaml] )"
+# configparser-3.2 breaks the build (3.3 or none at all are fine)
+DEPEND="${COMMON_DEPEND}
+	dev-lang/perl
+	>=sys-devel/make-3.81
+	>=sys-devel/flex-2.5.4
+	>=sys-devel/bison-1.875d
+	|| ( >=sys-devel/gcc-3.0 >=sys-devel/llvm-3.5
+		( >=sys-freebsd/freebsd-lib-9.1-r10 sys-libs/libcxx )
+	)
+	|| ( >=sys-devel/binutils-2.18 >=sys-devel/binutils-apple-5.1 )
+	kernel_Darwin? ( <sys-libs/libcxx-${PV%_rc*}.9999 )
+	clang? ( xml? ( virtual/pkgconfig ) )
+	doc? ( dev-python/sphinx )
+	gold? ( sys-libs/binutils-libs )
+	libffi? ( virtual/pkgconfig )
+	lldb? ( dev-lang/swig )
+	!!<dev-python/configparser-3.3.0.2
+	ocaml? ( test? ( dev-ml/ounit ) )
+	${PYTHON_DEPS}"
+RDEPEND="${COMMON_DEPEND}
+	clang? ( !<=sys-devel/clang-${PV}-r99 )
+	abi_x86_32? ( !<=app-emulation/emul-linux-x86-baselibs-20130224-r2
+		!app-emulation/emul-linux-x86-baselibs[-abi_x86_32(-)] )"
+PDEPEND="clang? ( =sys-devel/clang-${PV}-r100 )"
+
+# pypy gives me around 1700 unresolved tests due to open file limit
+# being exceeded. probably GC does not close them fast enough.
+REQUIRED_USE="${PYTHON_REQUIRED_USE}
+	lldb? ( clang xml )"
+
+S=${WORKDIR}/${P/_}.src
+
+pkg_pretend() {
+	# in megs
+	# !clang !debug !multitarget -O2       400
+	# !clang !debug  multitarget -O2       550
+	#  clang !debug !multitarget -O2       950
+	#  clang !debug  multitarget -O2      1200
+	# !clang  debug  multitarget -O2      5G
+	#  clang !debug  multitarget -O0 -g  12G
+	#  clang  debug  multitarget -O2     16G
+	#  clang  debug  multitarget -O0 -g  14G
+
+	local build_size=550
+	use clang && build_size=1200
+
+	if use debug; then
+		ewarn "USE=debug is known to increase the size of package considerably"
+		ewarn "and cause the tests to fail."
+		ewarn
+
+		(( build_size *= 14 ))
+	elif is-flagq '-g?(gdb)?([1-9])'; then
+		ewarn "The C++ compiler -g option is known to increase the size of the package"
+		ewarn "considerably. If you run out of space, please consider removing it."
+		ewarn
+
+		(( build_size *= 10 ))
+	fi
+
+	# Multiply by number of ABIs :).
+	local abis=( $(multilib_get_enabled_abis) )
+	(( build_size *= ${#abis[@]} ))
+
+	local CHECKREQS_DISK_BUILD=${build_size}M
+	check-reqs_pkg_pretend
+
+	if [[ ${MERGE_TYPE} != binary ]]; then
+		echo 'int main() {return 0;}' > "${T}"/test.cxx || die
+		ebegin "Trying to build a C++11 test program"
+		if ! $(tc-getCXX) -std=c++11 -o /dev/null "${T}"/test.cxx; then
+			eerror "LLVM-${PV} requires C++11-capable C++ compiler. Your current compiler"
+			eerror "does not seem to support -std=c++11 option. Please upgrade your compiler"
+			eerror "to gcc-4.7 or an equivalent version supporting C++11."
+			die "Currently active compiler does not support -std=c++11"
+		fi
+		eend ${?}
+	fi
+}
+
+pkg_setup() {
+	pkg_pretend
+}
+
+src_unpack() {
+	default
+
+	if use clang; then
+		mv "${WORKDIR}"/cfe-${PV/_}.src "${S}"/tools/clang \
+			|| die "clang source directory move failed"
+		mv "${WORKDIR}"/compiler-rt-${PV/_}.src "${S}"/projects/compiler-rt \
+			|| die "compiler-rt source directory move failed"
+		mv "${WORKDIR}"/clang-tools-extra-${PV/_}.src "${S}"/tools/clang/tools/extra \
+			|| die "clang-tools-extra source directory move failed"
+	fi
+
+	if use lldb; then
+		mv "${WORKDIR}"/lldb-${PV/_}.src "${S}"/tools/lldb \
+			|| die "lldb source directory move failed"
+	fi
+}
+
+src_prepare() {
+	# Make ocaml warnings non-fatal, bug #537308
+	sed -e "/RUN/s/-warn-error A//" -i test/Bindings/OCaml/*ml  || die
+	# Fix libdir for ocaml bindings install, bug #559134
+	epatch "${FILESDIR}"/cmake/${PN}-3.7.0-ocaml-multilib.patch
+	# Do not build/install ocaml docs with USE=-doc, bug #562008
+	epatch "${FILESDIR}"/cmake/${PN}-3.7.0-ocaml-build_doc.patch
+
+	# Make it possible to override Sphinx HTML install dirs
+	# https://llvm.org/bugs/show_bug.cgi?id=23780
+	epatch "${FILESDIR}"/cmake/0002-cmake-Support-overriding-Sphinx-HTML-doc-install-dir.patch
+
+	# Prevent race conditions with parallel Sphinx runs
+	# https://llvm.org/bugs/show_bug.cgi?id=23781
+	epatch "${FILESDIR}"/cmake/0003-cmake-Add-an-ordering-dep-between-HTML-man-Sphinx-ta.patch
+
+	# Prevent installing libgtest
+	# https://llvm.org/bugs/show_bug.cgi?id=18341
+	epatch "${FILESDIR}"/cmake/0004-cmake-Do-not-install-libgtest.patch
+
+	# Fix llvm-config for shared linking, sane flags and return values
+	# in order:
+	# - backported r247159 that adds --build-system (needed for later code)
+	# - backported r252532 that adds better shared linking support
+	# - our fixes
+	# - backported r260343 that fixes cross-compilation
+	# combination of backported upstream r252532 with our patch
+	# https://bugs.gentoo.org/show_bug.cgi?id=565358
+	epatch "${FILESDIR}"/llvm-3.7.1-llvm-config-0.patch
+	epatch "${FILESDIR}"/llvm-3.7.1-llvm-config-1.patch
+	epatch "${FILESDIR}"/llvm-3.7.1-llvm-config-2.patch
+	epatch "${FILESDIR}"/llvm-3.7.1-llvm-config-3.patch
+
+	# Fix msan with newer kernels, #569894
+	epatch "${FILESDIR}"/llvm-3.7-msan-fix.patch
+
+	# disable use of SDK on OSX, bug #568758
+	sed -i -e 's/xcrun/false/' utils/lit/lit/util.py || die
+
+	if use clang; then
+		# Automatically select active system GCC's libraries, bugs #406163 and #417913
+		epatch "${FILESDIR}"/clang-3.5-gentoo-runtime-gcc-detection-v3.patch
+
+		epatch "${FILESDIR}"/clang-3.6-gentoo-install.patch
+
+		epatch "${FILESDIR}"/clang-3.4-darwin_prefix-include-paths.patch
+		eprefixify tools/clang/lib/Frontend/InitHeaderSearch.cpp
+
+		sed -i -e "s^@EPREFIX@^${EPREFIX}^" \
+			tools/clang/tools/scan-build/scan-build || die
+
+		# Install clang runtime into /usr/lib/clang
+		# https://llvm.org/bugs/show_bug.cgi?id=23792
+		epatch "${FILESDIR}"/cmake/clang-0001-Install-clang-runtime-into-usr-lib-without-suffix.patch
+		epatch "${FILESDIR}"/cmake/compiler-rt-0001-cmake-Install-compiler-rt-into-usr-lib-without-suffi.patch
+
+		# Do not force -march flags on arm platforms
+		# https://bugs.gentoo.org/show_bug.cgi?id=562706
+		epatch "${FILESDIR}"/cmake/${PN}-3.7.0-compiler_rt_arm_march_flags.patch
+
+		# Make it possible to override CLANG_LIBDIR_SUFFIX
+		# (that is used only to find LLVMgold.so)
+		# https://llvm.org/bugs/show_bug.cgi?id=23793
+		epatch "${FILESDIR}"/cmake/clang-0002-cmake-Make-CLANG_LIBDIR_SUFFIX-overridable.patch
+
+		pushd projects/compiler-rt >/dev/null || die
+
+		# Fix msan with newer kernels, compiler-rt part, #569894
+		epatch "${FILESDIR}"/compiler-rt-3.7-msan-fix.patch
+
+		# Fix WX sections, bug #421527
+		find lib/builtins -type f -name '*.S' -exec sed \
+			 -e '$a\\n#if defined(__linux__) && defined(__ELF__)\n.section .note.GNU-stack,"",%progbits\n#endif' \
+			 -i {} + || die
+
+		popd >/dev/null || die
+	fi
+
+	if use lldb; then
+		# Do not install dummy readline.so module from
+		# https://llvm.org/bugs/show_bug.cgi?id=18841
+		sed -e 's/add_subdirectory(readline)/#&/' \
+			-i tools/lldb/scripts/Python/modules/CMakeLists.txt || die
+
+		# Fix Python paths, bugs #562436 and #562438
+		epatch "${FILESDIR}"/${PN}-3.7-lldb_python.patch
+		sed -e "s/GENTOO_LIBDIR/$(get_libdir)/" \
+			-i tools/lldb/scripts/Python/finishSwigPythonLLDB.py || die
+
+		# Fix build with ncurses[tinfo], #560474
+		# http://llvm.org/viewvc/llvm-project?view=revision&revision=247842
+		epatch "${FILESDIR}"/cmake/${PN}-3.7.0-lldb_tinfo.patch
+	fi
+
+	# User patches
+	epatch_user
+
+	python_setup
+
+	# Native libdir is used to hold LLVMgold.so
+	NATIVE_LIBDIR=$(get_libdir)
+}
+
+multilib_src_configure() {
+	local targets
+	if use multitarget; then
+		targets=all
+	else
+		targets='host;BPF;CppBackend'
+		use video_cards_radeon && targets+=';AMDGPU'
+	fi
+
+	local ffi_cflags ffi_ldflags
+	if use libffi; then
+		ffi_cflags=$(pkg-config --cflags-only-I libffi)
+		ffi_ldflags=$(pkg-config --libs-only-L libffi)
+	fi
+
+	local libdir=$(get_libdir)
+	local mycmakeargs=(
+		-DLLVM_LIBDIR_SUFFIX=${libdir#lib}
+
+		-DBUILD_SHARED_LIBS=ON
+		-DLLVM_ENABLE_TIMESTAMPS=OFF
+		-DLLVM_TARGETS_TO_BUILD="${targets}"
+		-DLLVM_BUILD_TESTS=$(usex test)
+
+		-DLLVM_ENABLE_FFI=$(usex libffi)
+		-DLLVM_ENABLE_TERMINFO=$(usex ncurses)
+		-DLLVM_ENABLE_ASSERTIONS=$(usex debug)
+		-DLLVM_ENABLE_EH=ON
+		-DLLVM_ENABLE_RTTI=ON
+
+		-DWITH_POLLY=OFF # TODO
+
+		-DLLVM_HOST_TRIPLE="${CHOST}"
+
+		-DFFI_INCLUDE_DIR="${ffi_cflags#-I}"
+		-DFFI_LIBRARY_DIR="${ffi_ldflags#-L}"
+
+		-DHAVE_HISTEDIT_H=$(usex libedit)
+	)
+
+	if use clang; then
+		mycmakeargs+=(
+			-DCMAKE_DISABLE_FIND_PACKAGE_LibXml2=$(usex !xml)
+			# libgomp support fails to find headers without explicit -I
+			# furthermore, it provides only syntax checking
+			-DCLANG_DEFAULT_OPENMP_RUNTIME=libomp
+		)
+	fi
+
+	if use lldb; then
+		mycmakeargs+=(
+			-DLLDB_DISABLE_LIBEDIT=$(usex !libedit)
+			-DLLDB_DISABLE_CURSES=$(usex !ncurses)
+			-DLLDB_ENABLE_TERMINFO=$(usex ncurses)
+		)
+	fi
+
+	if ! multilib_is_native_abi || ! use ocaml; then
+		mycmakeargs+=(
+			-DOCAMLFIND=NO
+		)
+	fi
+#	Note: go bindings have no CMake rules at the moment
+#	but let's kill the check in case they are introduced
+#	if ! multilib_is_native_abi || ! use go; then
+		mycmakeargs+=(
+			-DGO_EXECUTABLE=GO_EXECUTABLE-NOTFOUND
+		)
+#	fi
+
+	if multilib_is_native_abi; then
+		mycmakeargs+=(
+			-DLLVM_BUILD_DOCS=$(usex doc)
+			-DLLVM_ENABLE_SPHINX=$(usex doc)
+			-DLLVM_ENABLE_DOXYGEN=OFF
+			-DLLVM_INSTALL_HTML="${EPREFIX}/usr/share/doc/${PF}/html"
+			-DSPHINX_WARNINGS_AS_ERRORS=OFF
+			-DLLVM_INSTALL_UTILS=ON
+		)
+
+		if use clang; then
+			mycmakeargs+=(
+				-DCLANG_INSTALL_HTML="${EPREFIX}/usr/share/doc/${PF}/clang"
+			)
+		fi
+
+		if use gold; then
+			mycmakeargs+=(
+				-DLLVM_BINUTILS_INCDIR="${EPREFIX}"/usr/include
+			)
+		fi
+
+		if use lldb; then
+			mycmakeargs+=(
+				-DLLDB_DISABLE_PYTHON=$(usex !python)
+			)
+		fi
+
+	else
+		if use clang; then
+			mycmakeargs+=(
+				# disable compiler-rt on non-native ABI because:
+				# 1. it fails to configure because of -m32
+				# 2. it is shared between ABIs so no point building
+				# it multiple times
+				-DLLVM_EXTERNAL_COMPILER_RT_BUILD=OFF
+				-DLLVM_EXTERNAL_CLANG_TOOLS_EXTRA_BUILD=OFF
+			)
+		fi
+		if use lldb; then
+			mycmakeargs+=(
+				# only run swig on native abi
+				-DLLDB_DISABLE_PYTHON=ON
+			)
+		fi
+	fi
+
+	if use clang; then
+		mycmakeargs+=(
+			-DCLANG_ENABLE_ARCMT=$(usex static-analyzer)
+			-DCLANG_ENABLE_STATIC_ANALYZER=$(usex static-analyzer)
+			-DCLANG_LIBDIR_SUFFIX="${NATIVE_LIBDIR#lib}"
+		)
+
+		# -- not needed when compiler-rt is built with host compiler --
+		# cmake passes host C*FLAGS to compiler-rt build
+		# which is performed using clang, so we need to filter out
+		# some flags clang does not support
+		# (if you know some more flags that don't work, let us know)
+		#filter-flags -msahf -frecord-gcc-switches
+	fi
+
+	cmake-utils_src_configure
+}
+
+multilib_src_compile() {
+	cmake-utils_src_compile
+	# TODO: not sure why this target is not correctly called
+	multilib_is_native_abi && use doc && use ocaml && cmake-utils_src_make docs/ocaml_doc
+
+	pax-mark m "${BUILD_DIR}"/bin/llvm-rtdyld
+	pax-mark m "${BUILD_DIR}"/bin/lli
+	pax-mark m "${BUILD_DIR}"/bin/lli-child-target
+
+	if use test; then
+		pax-mark m "${BUILD_DIR}"/unittests/ExecutionEngine/Orc/OrcJITTests
+		pax-mark m "${BUILD_DIR}"/unittests/ExecutionEngine/MCJIT/MCJITTests
+		pax-mark m "${BUILD_DIR}"/unittests/Support/SupportTests
+	fi
+}
+
+multilib_src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+	local test_targets=( check )
+	# clang tests won't work on non-native ABI because we skip compiler-rt
+	multilib_is_native_abi && use clang && test_targets+=( check-clang )
+	cmake-utils_src_make "${test_targets[@]}"
+}
+
+src_install() {
+	local MULTILIB_CHOST_TOOLS=(
+		/usr/bin/llvm-config
+	)
+
+	local MULTILIB_WRAPPED_HEADERS=(
+		/usr/include/llvm/Config/config.h
+		/usr/include/llvm/Config/llvm-config.h
+	)
+
+	if use clang; then
+		# note: magic applied in multilib_src_install()!
+		CLANG_VERSION=${PV%.*}
+
+		MULTILIB_CHOST_TOOLS+=(
+			/usr/bin/clang
+			/usr/bin/clang++
+			/usr/bin/clang-cl
+			/usr/bin/clang-${CLANG_VERSION}
+			/usr/bin/clang++-${CLANG_VERSION}
+			/usr/bin/clang-cl-${CLANG_VERSION}
+		)
+
+		MULTILIB_WRAPPED_HEADERS+=(
+			/usr/include/clang/Config/config.h
+		)
+	fi
+
+	multilib-minimal_src_install
+
+	# Remove unnecessary headers on FreeBSD, bug #417171
+	if use kernel_FreeBSD && use clang; then
+		rm "${ED}"usr/lib/clang/${PV}/include/{std,float,iso,limits,tgmath,varargs}*.h || die
+	fi
+}
+
+multilib_src_install() {
+	cmake-utils_src_install
+
+	if multilib_is_native_abi; then
+		# Install man pages.
+		use doc || doman "${WORKDIR}"/${PN}-3.7.0-manpages/*.1
+
+		# Symlink the gold plugin.
+		if use gold; then
+			dodir "/usr/${CHOST}/binutils-bin/lib/bfd-plugins"
+			dosym "../../../../$(get_libdir)/LLVMgold.so" \
+				"/usr/${CHOST}/binutils-bin/lib/bfd-plugins/LLVMgold.so"
+		fi
+	fi
+
+	# apply CHOST and CLANG_VERSION to clang executables
+	# they're statically linked so we don't have to worry about the lib
+	if use clang; then
+		local clang_tools=( clang clang++ clang-cl )
+		local i
+
+		# cmake gives us:
+		# - clang-X.Y
+		# - clang -> clang-X.Y
+		# - clang++, clang-cl -> clang
+		# we want to have:
+		# - clang-X.Y
+		# - clang++-X.Y, clang-cl-X.Y -> clang-X.Y
+		# - clang, clang++, clang-cl -> clang*-X.Y
+		# so we need to fix the two tools
+		for i in "${clang_tools[@]:1}"; do
+			rm "${ED%/}/usr/bin/${i}" || die
+			dosym "clang-${CLANG_VERSION}" "/usr/bin/${i}-${CLANG_VERSION}"
+			dosym "${i}-${CLANG_VERSION}" "/usr/bin/${i}"
+		done
+
+		# now prepend ${CHOST} and let the multilib-build.eclass symlink it
+		if ! multilib_is_native_abi; then
+			# non-native? let's replace it with a simple wrapper
+			for i in "${clang_tools[@]}"; do
+				rm "${ED%/}/usr/bin/${i}-${CLANG_VERSION}" || die
+				cat > "${T}"/wrapper.tmp <<-_EOF_
+					#!${EPREFIX}/bin/sh
+					exec "${i}-${CLANG_VERSION}" $(get_abi_CFLAGS) "\${@}"
+				_EOF_
+				newbin "${T}"/wrapper.tmp "${i}-${CLANG_VERSION}"
+			done
+		fi
+	fi
+}
+
+multilib_src_install_all() {
+	insinto /usr/share/vim/vimfiles
+	doins -r utils/vim/*/.
+	# some users may find it useful
+	dodoc utils/vim/vimrc
+
+	if use clang; then
+		pushd tools/clang >/dev/null || die
+
+		if use static-analyzer ; then
+			pushd tools/scan-build >/dev/null || die
+
+			dobin ccc-analyzer scan-build
+			dosym ccc-analyzer /usr/bin/c++-analyzer
+			doman scan-build.1
+
+			insinto /usr/share/llvm
+			doins scanview.css sorttable.js
+
+			popd >/dev/null || die
+		fi
+
+		if use static-analyzer ; then
+			pushd tools/scan-view >/dev/null || die
+
+			python_doscript scan-view
+
+			touch __init__.py || die
+			python_moduleinto clang
+			python_domodule *.py Resources
+
+			popd >/dev/null || die
+		fi
+
+		if use python ; then
+			pushd bindings/python/clang >/dev/null || die
+
+			python_moduleinto clang
+			python_domodule *.py
+
+			popd >/dev/null || die
+		fi
+
+		# AddressSanitizer symbolizer (currently separate)
+		dobin "${S}"/projects/compiler-rt/lib/asan/scripts/asan_symbolize.py
+
+		popd >/dev/null || die
+
+		python_fix_shebang "${ED}"
+		if use lldb && use python; then
+			python_optimize
+		fi
+	fi
+}
+
+pkg_postinst() {
+	if use clang && ! has_version sys-libs/libomp; then
+		elog "To enable OpenMP support in clang, install sys-libs/libomp."
+	fi
+}