Index: clang/lib/Driver/ToolChain.cpp
===================================================================
--- clang/lib/Driver/ToolChain.cpp
+++ clang/lib/Driver/ToolChain.cpp
@@ -74,6 +74,29 @@
                      const ArgList &Args)
     : D(D), Triple(T), Args(Args), CachedRTTIArg(GetRTTIArgument(Args)),
       CachedRTTIMode(CalculateRTTIMode(Args, Triple, CachedRTTIArg)) {
+  SmallString<128> P(D.ResourceDir);
+  llvm::sys::path::append(P, D.getTargetTriple(), "lib");
+  if (getVFS().exists(P))
+    getFilePaths().push_back(P.str());
+
+  Arg *A = Args.getLastArg(options::OPT_m64, options::OPT_mx32,
+                           options::OPT_m32, options::OPT_m16);
+  if (A) {
+    if (A->getOption().matches(options::OPT_m64) &&
+        Triple.isArch32Bit()) {
+      llvm::sys::path::append(P, "64");
+    } else if (A->getOption().matches(options::OPT_mx32) &&
+               Triple.isArch64Bit()) {
+      llvm::sys::path::append(P, "x32");
+    } else if (A->getOption().matches(options::OPT_m32) &&
+               Triple.isArch64Bit()) {
+      llvm::sys::path::append(P, "32");
+    } else if (A->getOption().matches(options::OPT_m16) &&
+               Triple.isArch32Bit()) {
+      llvm::sys::path::append(P, "16");
+    }
+  }
+
   std::string CandidateLibPath = getArchSpecificLibPath();
   if (getVFS().exists(CandidateLibPath))
     getFilePaths().push_back(CandidateLibPath);
@@ -350,15 +373,42 @@
 std::string ToolChain::getCompilerRT(const ArgList &Args, StringRef Component,
                                      bool Shared) const {
   const llvm::Triple &TT = getTriple();
-  const char *Env = TT.isAndroid() ? "-android" : "";
   bool IsITANMSVCWindows =
       TT.isWindowsMSVCEnvironment() || TT.isWindowsItaniumEnvironment();
 
-  StringRef Arch = getArchNameForCompilerRTLib(*this, Args);
   const char *Prefix = IsITANMSVCWindows ? "" : "lib";
   const char *Suffix = Shared ? (Triple.isOSWindows() ? ".dll" : ".so")
                               : (IsITANMSVCWindows ? ".lib" : ".a");
 
+  const Driver &D = getDriver();
+  SmallString<128> P(D.ResourceDir);
+  llvm::sys::path::append(P, D.getTargetTriple(), "lib");
+
+  Arg *A = Args.getLastArg(options::OPT_m64, options::OPT_mx32,
+                           options::OPT_m32, options::OPT_m16);
+  if (A) {
+    if (A->getOption().matches(options::OPT_m64) &&
+        Triple.isArch32Bit()) {
+      llvm::sys::path::append(P, "64");
+    } else if (A->getOption().matches(options::OPT_mx32) &&
+               Triple.isArch64Bit()) {
+      llvm::sys::path::append(P, "x32");
+    } else if (A->getOption().matches(options::OPT_m32) &&
+               Triple.isArch64Bit()) {
+      llvm::sys::path::append(P, "32");
+    } else if (A->getOption().matches(options::OPT_m16) &&
+               Triple.isArch32Bit()) {
+      llvm::sys::path::append(P, "16");
+    }
+  }
+
+  if (getVFS().exists(P)) {
+    llvm::sys::path::append(P, Prefix + Twine("clang_rt.") + Component + Suffix);
+    return P.str();
+  }
+
+  StringRef Arch = getArchNameForCompilerRTLib(*this, Args);
+  const char *Env = TT.isAndroid() ? "-android" : "";
   SmallString<128> Path(getCompilerRTPath());
   llvm::sys::path::append(Path, Prefix + Twine("clang_rt.") + Component + "-" +
                                     Arch + Env + Suffix);
Index: clang/lib/Driver/ToolChains/Fuchsia.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Fuchsia.cpp
+++ clang/lib/Driver/ToolChains/Fuchsia.cpp
@@ -144,21 +144,6 @@
 
 /// Fuchsia - Fuchsia tool chain which can call as(1) and ld(1) directly.
 
-static std::string normalizeTriple(llvm::Triple Triple) {
-  SmallString<64> T;
-  T += Triple.getArchName();
-  T += "-";
-  T += Triple.getOSName();
-  return T.str();
-}
-
-static std::string getTargetDir(const Driver &D,
-                                llvm::Triple Triple) {
-  SmallString<128> P(llvm::sys::path::parent_path(D.Dir));
-  llvm::sys::path::append(P, "lib", normalizeTriple(Triple));
-  return P.str();
-}
-
 Fuchsia::Fuchsia(const Driver &D, const llvm::Triple &Triple,
                  const ArgList &Args)
     : ToolChain(D, Triple, Args) {
@@ -166,10 +151,6 @@
   if (getDriver().getInstalledDir() != D.Dir)
     getProgramPaths().push_back(D.Dir);
 
-  SmallString<128> P(getTargetDir(D, getTriple()));
-  llvm::sys::path::append(P, "lib");
-  getFilePaths().push_back(P.str());
-
   if (!D.SysRoot.empty()) {
     SmallString<128> P(D.SysRoot);
     llvm::sys::path::append(P, "lib");
@@ -180,8 +161,7 @@
 std::string Fuchsia::ComputeEffectiveClangTriple(const ArgList &Args,
                                                  types::ID InputType) const {
   llvm::Triple Triple(ComputeLLVMTriple(Args, InputType));
-  Triple.setTriple(normalizeTriple(Triple));
-  return Triple.getTriple();
+  return (Triple.getArchName() + "-" + Triple.getOSName()).str();
 }
 
 Tool *Fuchsia::buildLinker() const {
@@ -264,7 +244,7 @@
 
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
-    SmallString<128> P(getTargetDir(getDriver(), getTriple()));
+    SmallString<128> P(getDriver().ResourceDir);
     llvm::sys::path::append(P, "include", "c++", "v1");
     addSystemInclude(DriverArgs, CC1Args, P.str());
     break;
Index: clang/lib/Driver/ToolChains/Linux.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Linux.cpp
+++ clang/lib/Driver/ToolChains/Linux.cpp
@@ -803,6 +803,7 @@
                                   llvm::opt::ArgStringList &CC1Args) const {
   const std::string& SysRoot = computeSysRoot();
   const std::string LibCXXIncludePathCandidates[] = {
+      DetectLibcxxIncludePath(getDriver().ResourceDir + "/include/c++"),
       DetectLibcxxIncludePath(getDriver().Dir + "/../include/c++"),
       // If this is a development, non-installed, clang, libcxx will
       // not be found at ../include/c++ but it likely to be found at
Index: clang/test/CMakeLists.txt
===================================================================
--- clang/test/CMakeLists.txt
+++ clang/test/CMakeLists.txt
@@ -23,7 +23,8 @@
   CLANG_ENABLE_ARCMT
   CLANG_ENABLE_STATIC_ANALYZER
   ENABLE_BACKTRACES
-  HAVE_LIBZ)
+  HAVE_LIBZ
+  LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
 
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
Index: clang/test/Driver/fuchsia.c
===================================================================
--- clang/test/Driver/fuchsia.c
+++ clang/test/Driver/fuchsia.c
@@ -1,7 +1,9 @@
-// RUN: %clang %s -### -no-canonical-prefixes --target=x86_64-unknown-fuchsia \
+// RUN: %clang %s -### -no-canonical-prefixes --target=x86_64-fuchsia \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     --sysroot=%S/platform 2>&1 \
 // RUN:     | FileCheck -check-prefixes=CHECK,CHECK-X86_64 %s
-// RUN: %clang %s -### -no-canonical-prefixes --target=aarch64-unknown-fuchsia \
+// RUN: %clang %s -### -no-canonical-prefixes --target=aarch64-fuchsia \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     --sysroot=%S/platform 2>&1 \
 // RUN:     | FileCheck -check-prefixes=CHECK,CHECK-AARCH64 %s
 // CHECK: {{.*}}clang{{.*}}" "-cc1"
@@ -23,97 +25,106 @@
 // CHECK-NOT: crti.o
 // CHECK-NOT: crtbegin.o
 // CHECK: "-L[[SYSROOT]]{{/|\\\\}}lib"
-// CHECK-X86_64: "{{.*[/\\]}}libclang_rt.builtins-x86_64.a"
-// CHECK-AARCH64: "{{.*[/\\]}}libclang_rt.builtins-aarch64.a"
+// CHECK-X86_64: "{{.*[/\\]}}libclang_rt.builtins.a"
+// CHECK-AARCH64: "{{.*[/\\]}}libclang_rt.builtins.a"
 // CHECK: "-lc"
 // CHECK-NOT: crtend.o
 // CHECK-NOT: crtn.o
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia -rtlib=libgcc 2>&1 \
+// RUN: %clang %s -### --target=x86_64-fuchsia -rtlib=libgcc 2>&1 \
 // RUN:     | FileCheck %s -check-prefix=CHECK-RTLIB
 // CHECK-RTLIB: error: invalid runtime library name in argument '-rtlib=libgcc'
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia -static 2>&1 \
+// RUN: %clang %s -### --target=x86_64-fuchsia -static 2>&1 \
 // RUN:     | FileCheck %s -check-prefix=CHECK-STATIC
 // CHECK-STATIC: "-Bstatic"
 // CHECK-STATIC: "-Bdynamic"
 // CHECK-STATIC: "-lc"
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia -shared 2>&1 \
+// RUN: %clang %s -### --target=x86_64-fuchsia -shared 2>&1 \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SHARED
 // CHECK-SHARED-NOT: "-pie"
 // CHECK-SHARED: "-shared"
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia -r 2>&1 \
+// RUN: %clang %s -### --target=x86_64-fuchsia -r 2>&1 \
 // RUN:     | FileCheck %s -check-prefix=CHECK-RELOCATABLE
 // CHECK-RELOCATABLE-NOT: "-pie"
 // CHECK-RELOCATABLE-NOT: "--build-id"
 // CHECK-RELOCATABLE: "-r"
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia \
+// RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=safe-stack 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SAFESTACK
 // CHECK-SAFESTACK: "-fsanitize=safe-stack"
-// CHECK-SAFESTACK-NOT: "{{.*[/\\]}}libclang_rt.safestack-x86_64.a"
+// CHECK-SAFESTACK-NOT: "{{.*[/\\]}}libclang_rt.safestack.a"
 // CHECK-SAFESTACK-NOT: "__safestack_init"
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia \
+// RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=address 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-ASAN-X86
 // CHECK-ASAN-X86: "-fsanitize=address"
 // CHECK-ASAN-X86: "-fsanitize-address-globals-dead-stripping"
 // CHECK-ASAN-X86: "-dynamic-linker" "asan/ld.so.1"
-// CHECK-ASAN-X86: "{{.*[/\\]}}libclang_rt.asan-x86_64.so"
-// CHECK-ASAN-X86: "{{.*[/\\]}}libclang_rt.asan-preinit-x86_64.a"
+// CHECK-ASAN-X86: "{{.*[/\\]}}libclang_rt.asan.so"
+// CHECK-ASAN-X86: "{{.*[/\\]}}libclang_rt.asan-preinit.a"
 
 // RUN: %clang %s -### --target=aarch64-fuchsia \
 // RUN:     -fsanitize=address 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-ASAN-AARCH64
 // CHECK-ASAN-AARCH64: "-fsanitize=address"
 // CHECK-ASAN-AARCH64: "-fsanitize-address-globals-dead-stripping"
 // CHECK-ASAN-AARCH64: "-dynamic-linker" "asan/ld.so.1"
-// CHECK-ASAN-AARCH64: "{{.*[/\\]}}libclang_rt.asan-aarch64.so"
-// CHECK-ASAN-AARCH64: "{{.*[/\\]}}libclang_rt.asan-preinit-aarch64.a"
+// CHECK-ASAN-AARCH64: "{{.*[/\\]}}libclang_rt.asan.so"
+// CHECK-ASAN-AARCH64: "{{.*[/\\]}}libclang_rt.asan-preinit.a"
 
-// RUN: %clang %s -### --target=x86_64-unknown-fuchsia \
+// RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=address -fPIC -shared 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-ASAN-SHARED
 // CHECK-ASAN-SHARED: "-fsanitize=address"
 // CHECK-ASAN-SHARED: "-fsanitize-address-globals-dead-stripping"
-// CHECK-ASAN-SHARED: "{{.*[/\\]}}libclang_rt.asan-x86_64.so"
-// CHECK-ASAN-SHARED-NOT: "{{.*[/\\]}}libclang_rt.asan-preinit-x86_64.a"
+// CHECK-ASAN-SHARED: "{{.*[/\\]}}libclang_rt.asan.so"
+// CHECK-ASAN-SHARED-NOT: "{{.*[/\\]}}libclang_rt.asan-preinit.a"
 
 // RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=fuzzer 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-FUZZER-X86
 // CHECK-FUZZER-X86: "-fsanitize=fuzzer,fuzzer-no-link,safe-stack"
-// CHECK-FUZZER-X86: "{{.*[/\\]}}libclang_rt.fuzzer-x86_64.a"
+// CHECK-FUZZER-X86: "{{.*[/\\]}}libclang_rt.fuzzer.a"
 
 // RUN: %clang %s -### --target=aarch64-fuchsia \
 // RUN:     -fsanitize=fuzzer 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-FUZZER-AARCH64
 // CHECK-FUZZER-AARCH64: "-fsanitize=fuzzer,fuzzer-no-link,safe-stack"
-// CHECK-FUZZER-AARCH64: "{{.*[/\\]}}libclang_rt.fuzzer-aarch64.a"
+// CHECK-FUZZER-AARCH64: "{{.*[/\\]}}libclang_rt.fuzzer.a"
 
 // RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=scudo 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SCUDO-X86
 // CHECK-SCUDO-X86: "-fsanitize=safe-stack,scudo"
 // CHECK-SCUDO-X86: "-pie"
-// CHECK-SCUDO-X86: "{{.*[/\\]}}libclang_rt.scudo-x86_64.so"
+// CHECK-SCUDO-X86: "{{.*[/\\]}}libclang_rt.scudo.so"
 
 // RUN: %clang %s -### --target=aarch64-fuchsia \
 // RUN:     -fsanitize=scudo 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SCUDO-AARCH64
 // CHECK-SCUDO-AARCH64: "-fsanitize=safe-stack,scudo"
 // CHECK-SCUDO-AARCH64: "-pie"
-// CHECK-SCUDO-AARCH64: "{{.*[/\\]}}libclang_rt.scudo-aarch64.so"
+// CHECK-SCUDO-AARCH64: "{{.*[/\\]}}libclang_rt.scudo.so"
 
 // RUN: %clang %s -### --target=x86_64-fuchsia \
 // RUN:     -fsanitize=scudo -fPIC -shared 2>&1 \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
 // RUN:     | FileCheck %s -check-prefix=CHECK-SCUDO-SHARED
 // CHECK-SCUDO-SHARED: "-fsanitize=safe-stack,scudo"
-// CHECK-SCUDO-SHARED: "{{.*[/\\]}}libclang_rt.scudo-x86_64.so"
+// CHECK-SCUDO-SHARED: "{{.*[/\\]}}libclang_rt.scudo.so"
 
 // RUN: %clang %s -### --target=aarch64-fuchsia \
 // RUN:     -O3 -flto -mcpu=cortex-a53 2>&1 \
Index: clang/test/Driver/fuchsia.cpp
===================================================================
--- clang/test/Driver/fuchsia.cpp
+++ clang/test/Driver/fuchsia.cpp
@@ -4,7 +4,7 @@
 // CHECK: "-triple" "x86_64-fuchsia"
 // CHECK: "-fuse-init-array"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
-// CHECK: "-internal-isystem" "{{.*[/\\]}}x86_64-fuchsia{{/|\\\\}}include{{/|\\\\}}c++{{/|\\\\}}v1"
+// CHECK: "-internal-isystem" "{{.*[/\\]}}include{{/|\\\\}}c++{{/|\\\\}}v1"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
 // CHECK: {{.*}}ld.lld{{.*}}" "-z" "rodynamic"
 // CHECK: "--sysroot=[[SYSROOT]]"
Index: clang/test/Driver/linux-header-search.cpp
===================================================================
--- clang/test/Driver/linux-header-search.cpp
+++ clang/test/Driver/linux-header-search.cpp
@@ -7,6 +7,7 @@
 // RUN:     -target x86_64-unknown-linux-gnu \
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
 // RUN:     --gcc-toolchain="" \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-SYSROOT %s
@@ -18,6 +19,7 @@
 // RUN:     -target x86_64-unknown-linux-gnu \
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_libcxx_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
 // RUN:     --gcc-toolchain="" \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-INSTALL %s
@@ -30,6 +32,7 @@
 // RUN:     -target x86_64-unknown-linux-gnu \
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxxv2_tree \
 // RUN:     --gcc-toolchain="" \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXXV2-SYSROOT %s
@@ -41,6 +44,7 @@
 // RUN:     -target x86_64-unknown-linux-gnu \
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_libcxxv2_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxxv2_tree \
 // RUN:     --gcc-toolchain="" \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXXV2-INSTALL %s
@@ -54,6 +58,7 @@
 // RUN:     -target x86_64-unknown-linux-gnu \
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libstdcxx_libcxxv2_tree \
 // RUN:     --gcc-toolchain="" \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBSTDCXX-LIBCXXV2-SYSROOT %s
Index: clang/test/Driver/linux-ld.c
===================================================================
--- clang/test/Driver/linux-ld.c
+++ clang/test/Driver/linux-ld.c
@@ -426,6 +426,7 @@
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
 // RUN:     --gcc-toolchain="" \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-SYSROOT %s
 // CHECK-BASIC-LIBCXX-SYSROOT: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
@@ -438,6 +439,7 @@
 // RUN:     -stdlib=libc++ \
 // RUN:     -ccc-install-dir %S/Inputs/basic_linux_libcxx_tree/usr/bin \
 // RUN:     --gcc-toolchain="" \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
 // RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-INSTALL %s
 // CHECK-BASIC-LIBCXX-INSTALL: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
Index: clang/test/Driver/linux-per-target-runtime-dir.c
===================================================================
--- /dev/null
+++ clang/test/Driver/linux-per-target-runtime-dir.c
@@ -0,0 +1,21 @@
+// RUN: %clang -no-canonical-prefixes -x c++ %s -### -o %t.o 2>&1 \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     -stdlib=libc++ \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_libcxx_tree/usr/bin \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-PER-TARGET-RUNTIME %s
+// CHECK-PER-TARGET-RUNTIME: "{{[^"]*}}clang{{[^"]*}}" "-cc1"
+// CHECK-PER-TARGET-RUNTIME: "-resource-dir" "[[RESDIR:[^"]*]]"
+// CHECK-PER-TARGET-RUNTIME: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-PER-TARGET-RUNTIME: "-internal-isystem" "[[RESDIR]]/include/c++/v1"
+// CHECK-PER-TARGET-RUNTIME: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+// CHECK-PER-TARGET-RUNTIME: "--sysroot=[[SYSROOT]]"
+// CHECK-PER-TARGET-RUNTIME: "-L[[RESDIR]]/x86_64-linux-gnu/lib"
+
+// RUN: %clang -rtlib=compiler-rt -print-libgcc-file-name 2>&1 \
+// RUN:     --target=x86_64-linux-gnu \
+// RUN:     -resource-dir=%S/Inputs/resource_dir_with_per_target_subdir \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANGRT-X8664 %s
+// CHECK-CLANGRT-X8664: x86_64-linux-gnu/lib/libclang_rt.builtins.a
Index: compiler-rt/CMakeLists.txt
===================================================================
--- compiler-rt/CMakeLists.txt
+++ compiler-rt/CMakeLists.txt
@@ -102,6 +102,8 @@
 set(COMPILER_RT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(COMPILER_RT_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
+pythonize_bool(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
+
 # We support running instrumented tests when we're not cross compiling
 # and target a UNIX-like system or Windows.
 # We can run tests on Android even when we are cross-compiling.
Index: compiler-rt/cmake/Modules/AddCompilerRT.cmake
===================================================================
--- compiler-rt/cmake/Modules/AddCompilerRT.cmake
+++ compiler-rt/cmake/Modules/AddCompilerRT.cmake
@@ -109,10 +109,14 @@
 endfunction()
 
 macro(set_output_name output name arch)
-  if(ANDROID AND ${arch} STREQUAL "i386")
-    set(${output} "${name}-i686${COMPILER_RT_OS_SUFFIX}")
+  if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
+    set(${output} ${name})
   else()
-    set(${output} "${name}-${arch}${COMPILER_RT_OS_SUFFIX}")
+    if(ANDROID AND ${arch} STREQUAL "i386")
+      set(${output} "${name}-i686${COMPILER_RT_OS_SUFFIX}")
+    else()
+      set(${output} "${name}-${arch}${COMPILER_RT_OS_SUFFIX}")
+    endif()
   endif()
 endmacro()
 
@@ -168,6 +172,8 @@
         set(output_name_${libname} ${libname}${COMPILER_RT_OS_SUFFIX})
         set(sources_${libname} ${LIB_SOURCES})
         format_object_libs(sources_${libname} ${os} ${LIB_OBJECT_LIBS})
+        get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir_${libname})
+        get_compiler_rt_install_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} install_dir_${libname})
       endif()
     endforeach()
   else()
@@ -193,6 +199,8 @@
       format_object_libs(sources_${libname} ${arch} ${LIB_OBJECT_LIBS})
       set(libnames ${libnames} ${libname})
       set(extra_cflags_${libname} ${TARGET_${arch}_CFLAGS} ${NO_LTO_FLAGS} ${LIB_CFLAGS})
+      get_compiler_rt_output_dir(${arch} output_dir_${libname})
+      get_compiler_rt_install_dir(${arch} install_dir_${libname})
     endforeach()
   endif()
 
@@ -245,7 +253,7 @@
     set_target_link_flags(${libname} ${extra_link_flags_${libname}})
     set_property(TARGET ${libname} APPEND PROPERTY
                 COMPILE_DEFINITIONS ${LIB_DEFS})
-    set_target_output_directories(${libname} ${COMPILER_RT_LIBRARY_OUTPUT_DIR})
+    set_target_output_directories(${libname} ${output_dir_${libname}})
     set_target_properties(${libname} PROPERTIES
         OUTPUT_NAME ${output_name_${libname}})
     set_target_properties(${libname} PROPERTIES FOLDER "Compiler-RT Runtime")
@@ -270,11 +278,11 @@
       endif()
     endif()
     install(TARGETS ${libname}
-      ARCHIVE DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
+      ARCHIVE DESTINATION ${install_dir_${libname}}
               ${COMPONENT_OPTION}
-      LIBRARY DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
+      LIBRARY DESTINATION ${install_dir_${libname}}
               ${COMPONENT_OPTION}
-      RUNTIME DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR}
+      RUNTIME DESTINATION ${install_dir_${libname}}
               ${COMPONENT_OPTION})
 
     # We only want to generate per-library install targets if you aren't using
@@ -621,8 +629,10 @@
 function(configure_compiler_rt_lit_site_cfg input output)
   set_llvm_build_mode()
 
+  get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir)
+
   string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_TEST_COMPILER ${COMPILER_RT_TEST_COMPILER})
-  string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_LIBRARY_OUTPUT_DIR ${COMPILER_RT_LIBRARY_OUTPUT_DIR})
+  string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} COMPILER_RT_RESOLVED_LIBRARY_OUTPUT_DIR ${output_dir})
 
   configure_lit_site_cfg(${input} ${output})
 endfunction()
Index: compiler-rt/cmake/Modules/CompilerRTUtils.cmake
===================================================================
--- compiler-rt/cmake/Modules/CompilerRTUtils.cmake
+++ compiler-rt/cmake/Modules/CompilerRTUtils.cmake
@@ -314,3 +314,33 @@
   endforeach ()
   set(${output_var} ${intermediate} PARENT_SCOPE)
 endfunction()
+
+function(get_compiler_rt_target arch variable)
+  if(ANDROID AND ${arch} STREQUAL "i386")
+    set(target "i686${COMPILER_RT_OS_SUFFIX}-${COMPILER_RT_DEFAULT_TARGET_OS}")
+  else()
+    set(target "${arch}-${COMPILER_RT_DEFAULT_TARGET_OS}")
+  endif()
+  if(COMPILER_RT_DEFAULT_TARGET_ABI)
+    set(target "${target}-${COMPILER_RT_DEFAULT_TARGET_ABI}")
+  endif()
+  set(${variable} ${target} PARENT_SCOPE)
+endfunction()
+
+function(get_compiler_rt_install_dir arch install_dir)
+  if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+    get_compiler_rt_target(${arch} target)
+    set(${install_dir} ${COMPILER_RT_INSTALL_PATH}/${target}/lib PARENT_SCOPE)
+  else()
+    set(${install_dir} ${COMPILER_RT_LIBRARY_INSTALL_DIR} PARENT_SCOPE)
+  endif()
+endfunction()
+
+function(get_compiler_rt_output_dir arch output_dir)
+  if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+    get_compiler_rt_target(${arch} target)
+    set(${output_dir} ${COMPILER_RT_OUTPUT_DIR}/${target}/lib PARENT_SCOPE)
+  else()
+    set(${output_dir} ${COMPILER_RT_LIBRARY_OUTPUT_DIR} PARENT_SCOPE)
+  endif()
+endfunction()
Index: compiler-rt/cmake/Modules/SanitizerUtils.cmake
===================================================================
--- compiler-rt/cmake/Modules/SanitizerUtils.cmake
+++ compiler-rt/cmake/Modules/SanitizerUtils.cmake
@@ -1,3 +1,5 @@
+include(CompilerRTUtils)
+
 set(SANITIZER_GEN_DYNAMIC_LIST
   ${COMPILER_RT_SOURCE_DIR}/lib/sanitizer_common/scripts/gen_dynamic_list.py)
 
@@ -37,9 +39,9 @@
     add_custom_target(${target_name}-symbols ALL
       DEPENDS ${stamp}
       SOURCES ${SANITIZER_GEN_DYNAMIC_LIST} ${ARG_EXTRA})
-
+    get_compiler_rt_install_dir(${arch} install_dir)
     install(FILES $<TARGET_FILE:${target_name}>.syms
-            DESTINATION ${COMPILER_RT_LIBRARY_INSTALL_DIR})
+            DESTINATION ${install_dir})
     if(ARG_PARENT_TARGET)
       add_dependencies(${ARG_PARENT_TARGET} ${target_name}-symbols)
     endif()
Index: compiler-rt/cmake/base-config-ix.cmake
===================================================================
--- compiler-rt/cmake/base-config-ix.cmake
+++ compiler-rt/cmake/base-config-ix.cmake
@@ -76,10 +76,17 @@
 if(NOT DEFINED COMPILER_RT_OS_DIR)
   string(TOLOWER ${CMAKE_SYSTEM_NAME} COMPILER_RT_OS_DIR)
 endif()
-set(COMPILER_RT_LIBRARY_OUTPUT_DIR
-  ${COMPILER_RT_OUTPUT_DIR}/lib/${COMPILER_RT_OS_DIR})
-set(COMPILER_RT_LIBRARY_INSTALL_DIR
-  ${COMPILER_RT_INSTALL_PATH}/lib/${COMPILER_RT_OS_DIR})
+if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+  set(COMPILER_RT_LIBRARY_OUTPUT_DIR
+    ${COMPILER_RT_OUTPUT_DIR})
+  set(COMPILER_RT_LIBRARY_INSTALL_DIR
+    ${COMPILER_RT_INSTALL_PATH})
+else(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
+  set(COMPILER_RT_LIBRARY_OUTPUT_DIR
+    ${COMPILER_RT_OUTPUT_DIR}/lib/${COMPILER_RT_OS_DIR})
+  set(COMPILER_RT_LIBRARY_INSTALL_DIR
+    ${COMPILER_RT_INSTALL_PATH}/lib/${COMPILER_RT_OS_DIR})
+endif()
 
 if(APPLE)
   # On Darwin if /usr/include doesn't exist, the user probably has Xcode but not
Index: compiler-rt/cmake/config-ix.cmake
===================================================================
--- compiler-rt/cmake/config-ix.cmake
+++ compiler-rt/cmake/config-ix.cmake
@@ -384,7 +384,6 @@
   # for list_intersect
   include(CompilerRTUtils)
 
-
   list_intersect(SANITIZER_COMMON_SUPPORTED_ARCH
     ALL_SANITIZER_COMMON_SUPPORTED_ARCH
     COMPILER_RT_SUPPORTED_ARCH
Index: compiler-rt/test/asan/lit.cfg
===================================================================
--- compiler-rt/test/asan/lit.cfg
+++ compiler-rt/test/asan/lit.cfg
@@ -101,7 +101,7 @@
 config.substitutions.append( ("%clangxx ", build_invocation(target_cxxflags)) )
 config.substitutions.append( ("%clang_asan ", build_invocation(clang_asan_cflags)) )
 config.substitutions.append( ("%clangxx_asan ", build_invocation(clang_asan_cxxflags)) )
-config.substitutions.append( ("%shared_libasan", "libclang_rt.asan-%s.so" % config.target_arch))
+config.substitutions.append( ("%shared_libasan", "libclang_rt.asan%s.so" % config.target_suffix))
 if config.asan_dynamic:
   config.substitutions.append( ("%clang_asan_static ", build_invocation(clang_asan_static_cflags)) )
   config.substitutions.append( ("%clangxx_asan_static ", build_invocation(clang_asan_static_cxxflags)) )
@@ -124,7 +124,7 @@
   clang_cl_asan_invocation = clang_cl_asan_invocation.replace("clang.exe","clang-cl.exe")
   config.substitutions.append( ("%clang_cl_asan ", clang_cl_asan_invocation) )
 
-  base_lib = os.path.join(config.compiler_rt_libdir, "clang_rt.asan%%s-%s.lib" % config.target_arch)
+  base_lib = os.path.join(config.compiler_rt_libdir, "clang_rt.asan%%s%s.lib" % config.target_suffix)
   config.substitutions.append( ("%asan_lib", base_lib % "") )
   config.substitutions.append( ("%asan_cxx_lib", base_lib % "_cxx") )
   config.substitutions.append( ("%asan_dll_thunk", base_lib % "_dll_thunk") )
Index: compiler-rt/test/builtins/Unit/lit.cfg
===================================================================
--- compiler-rt/test/builtins/Unit/lit.cfg
+++ compiler-rt/test/builtins/Unit/lit.cfg
@@ -26,12 +26,12 @@
 # Path to the static library
 is_msvc = get_required_attr(config, "builtins_is_msvc")
 if is_msvc:
-  base_lib = os.path.join(config.compiler_rt_libdir, "clang_rt.builtins-%s.lib "
-                          % config.target_arch)
+  base_lib = os.path.join(config.compiler_rt_libdir, "clang_rt.builtins%s.lib "
+                          % config.target_suffix)
   config.substitutions.append( ("%librt ", base_lib) )
 else:
-  base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins-%s.a"
-                          % config.target_arch)
+  base_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.builtins%s.a"
+                          % config.target_suffix)
   config.substitutions.append( ("%librt ", base_lib + ' -lc -lm ') )
 
 builtins_source_dir = os.path.join(
Index: compiler-rt/test/fuzzer/lit.cfg
===================================================================
--- compiler-rt/test/fuzzer/lit.cfg
+++ compiler-rt/test/fuzzer/lit.cfg
@@ -53,10 +53,10 @@
   compiler_cmd = config.clang
   extra_cmd = config.target_flags
   if config.clang and config.stdlib == 'libc++':
-    link_cmd = '-stdlib=libc++ -Wl,-rpath=%s' % config.llvm_library_dir
+    link_cmd = '-stdlib=libc++ -Wl,-rpath=%s' % config.runtime_library_dir
   elif config.clang and config.stdlib == 'static-libc++':
     link_cmd = '-stdlib=libc++ -lc++abi -static-libstdc++ -Wl,-rpath=%s' % (
-        config.llvm_library_dir)
+        config.runtime_library_dir)
   elif any(x in config.target_triple for x in ('darwin', 'freebsd')):
     link_cmd = '-lc++'
   else:
Index: compiler-rt/test/fuzzer/lit.site.cfg.in
===================================================================
--- compiler-rt/test/fuzzer/lit.site.cfg.in
+++ compiler-rt/test/fuzzer/lit.site.cfg.in
@@ -18,4 +18,9 @@
 lit_config.load_config(config,
     "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
 
+if config.enable_per_target_runtime_dir:
+  config.runtime_library_dir = config.compiler_rt_libdir
+else:
+  config.runtime_library_dir = "@LLVM_LIBRARY_DIR@"
+
 lit_config.load_config(config, "@CMAKE_CURRENT_SOURCE_DIR@/lit.cfg")
Index: compiler-rt/test/lit.common.configured.in
===================================================================
--- compiler-rt/test/lit.common.configured.in
+++ compiler-rt/test/lit.common.configured.in
@@ -16,6 +16,7 @@
 set_default("llvm_obj_root", "@LLVM_BINARY_DIR@")
 set_default("compiler_rt_src_root", "@COMPILER_RT_SOURCE_DIR@")
 set_default("compiler_rt_obj_root", "@COMPILER_RT_BINARY_DIR@")
+set_default("enable_per_target_runtime_dir", @LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_PYBOOL@)
 set_default("llvm_tools_dir", "@LLVM_TOOLS_DIR@")
 set_default("llvm_shlib_dir", "@LLVM_LIBRARY_OUTPUT_INTDIR@")
 set_default("gold_executable", "@GOLD_EXECUTABLE@")
@@ -36,6 +37,11 @@
 set_default("android", @ANDROID_PYBOOL@)
 config.available_features.add('target-is-%s' % config.target_arch)
 
+if config.enable_per_target_runtime_dir:
+  set_default("target_suffix", "")
+else:
+  set_default("target_suffix", "-%s" % config.target_arch)
+
 # LLVM tools dir can be passed in lit parameters, so try to
 # apply substitution.
 try:
Index: compiler-rt/test/scudo/lit.cfg
===================================================================
--- compiler-rt/test/scudo/lit.cfg
+++ compiler-rt/test/scudo/lit.cfg
@@ -9,7 +9,7 @@
 config.test_source_root = os.path.dirname(__file__)
 
 # Path to the shared library
-shared_libscudo = os.path.join(config.compiler_rt_libdir, "libclang_rt.scudo-%s.so" % config.target_arch)
+shared_libscudo = os.path.join(config.compiler_rt_libdir, "libclang_rt.scudo%s.so" % config.target_suffix)
 
 # Test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp']
Index: compiler-rt/test/xray/lit.cfg
===================================================================
--- compiler-rt/test/xray/lit.cfg
+++ compiler-rt/test/xray/lit.cfg
@@ -18,9 +18,6 @@
 
 # Assume that llvm-xray is in the config.llvm_tools_dir.
 llvm_xray = os.path.join(config.llvm_tools_dir, 'llvm-xray')
-host_arch = config.host_arch
-if host_arch == 'amd64':
-  host_arch = 'x86_64'
 
 # Setup substitutions.
 if config.host_os == "Linux":
@@ -42,8 +39,8 @@
 config.substitutions.append(
     ('%xraylib',
         ('-lm -lpthread %s -lrt -L%s '
-         '-Wl,-whole-archive -lclang_rt.xray-%s -Wl,-no-whole-archive')
-        % (libdl_flag, config.compiler_rt_libdir, host_arch)))
+         '-Wl,-whole-archive -lclang_rt.xray%s -Wl,-no-whole-archive')
+        % (libdl_flag, config.compiler_rt_libdir, config.target_suffix)))
 
 # Default test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp']
Index: libcxx/CMakeLists.txt
===================================================================
--- libcxx/CMakeLists.txt
+++ libcxx/CMakeLists.txt
@@ -378,20 +378,30 @@
 set(LIBCXX_COMPILER    ${CMAKE_CXX_COMPILER})
 set(LIBCXX_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
 set(LIBCXX_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
+set(LIBCXX_HEADER_DIR  ${LLVM_BINARY_DIR})
 set(LIBCXX_BINARY_INCLUDE_DIR "${LIBCXX_BINARY_DIR}/include/c++build")
-if (LLVM_LIBRARY_OUTPUT_INTDIR)
+
+string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+       ${PACKAGE_VERSION})
+
+if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+  set(DEFAULT_INSTALL_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/)
+  set(DEFAULT_INSTALL_HEADER_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/)
+  set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LLVM_RUNTIMES_LIBDIR_SUFFIX})
+  set(LIBCXX_HEADER_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION})
+elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
 else()
   set(LIBCXX_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
 endif()
+
 file(MAKE_DIRECTORY "${LIBCXX_BINARY_INCLUDE_DIR}")
 
-set(LIBCXX_INSTALL_PREFIX "" CACHE STRING
+set(LIBCXX_INSTALL_PREFIX ${DEFAULT_INSTALL_PREFIX} CACHE STRING
     "Define libc++ destination prefix.")
 
-if (NOT LIBCXX_INSTALL_PREFIX MATCHES "^$|.*/")
-  message(FATAL_ERROR "LIBCXX_INSTALL_PREFIX has to end with \"/\".")
-endif()
+set(LIBCXX_INSTALL_HEADER_PREFIX ${DEFAULT_INSTALL_HEADER_PREFIX} CACHE STRING
+    "Define libc++ header destination prefix.")
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
Index: libcxx/cmake/Modules/HandleLibCXXABI.cmake
===================================================================
--- libcxx/cmake/Modules/HandleLibCXXABI.cmake
+++ libcxx/cmake/Modules/HandleLibCXXABI.cmake
@@ -65,7 +65,7 @@
 
         if (LIBCXX_INSTALL_HEADERS)
           install(FILES "${LIBCXX_BINARY_INCLUDE_DIR}/${fpath}"
-            DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1/${dstdir}
+            DESTINATION ${LIBCXX_INSTALL_PATH}include/c++/v1/${dstdir}
             COMPONENT cxx-headers
             PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
             )
Index: libcxx/include/CMakeLists.txt
===================================================================
--- libcxx/include/CMakeLists.txt
+++ libcxx/include/CMakeLists.txt
@@ -204,7 +204,7 @@
 endif()
 
 if(NOT LIBCXX_USING_INSTALLED_LLVM AND LLVM_BINARY_DIR)
-  set(output_dir ${LLVM_BINARY_DIR}/include/c++/v1)
+  set(output_dir ${LIBCXX_HEADER_DIR}/include/c++/v1)
 
   set(out_files)
   foreach(f ${files})
@@ -238,7 +238,7 @@
   foreach(file ${files})
     get_filename_component(dir ${file} DIRECTORY)
     install(FILES ${file}
-      DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1/${dir}
+      DESTINATION ${LIBCXX_INSTALL_PATH}include/c++/v1/${dir}
       COMPONENT cxx-headers
       PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
     )
@@ -247,7 +247,7 @@
   if (LIBCXX_NEEDS_SITE_CONFIG)
     # Install the generated header as __config.
     install(FILES ${LIBCXX_BINARY_DIR}/__generated_config
-      DESTINATION ${LIBCXX_INSTALL_PREFIX}include/c++/v1
+      DESTINATION ${LIBCXX_INSTALL_PATH}include/c++/v1
       PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
       RENAME __config
       COMPONENT cxx-headers)
Index: libcxxabi/CMakeLists.txt
===================================================================
--- libcxxabi/CMakeLists.txt
+++ libcxxabi/CMakeLists.txt
@@ -154,19 +154,22 @@
 set(LIBCXXABI_COMPILER    ${CMAKE_CXX_COMPILER})
 set(LIBCXXABI_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
 set(LIBCXXABI_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
-if (LLVM_LIBRARY_OUTPUT_INTDIR)
+
+string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+       ${PACKAGE_VERSION})
+
+if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+  set(DEFAULT_INSTALL_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/)
+  set(LIBCXXABI_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LLVM_RUNTIMES_LIBDIR_SUFFIX})
+elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBCXXABI_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
 else()
-  set(LIBCXXABI_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXXABI_LIBDIR_SUFFIX})
+  set(LIBCXXABI_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
 endif()
 
-set(LIBCXXABI_INSTALL_PREFIX "" CACHE STRING
+set(LIBCXXABI_INSTALL_PREFIX ${DEFAULT_INSTALL_PREFIX} CACHE STRING
     "Define libc++abi destination prefix.")
 
-if (NOT LIBCXXABI_INSTALL_PREFIX MATCHES "^$|.*/")
-  message(FATAL_ERROR "LIBCXXABI_INSTALL_PREFIX has to end with \"/\".")
-endif()
-
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
Index: libunwind/CMakeLists.txt
===================================================================
--- libunwind/CMakeLists.txt
+++ libunwind/CMakeLists.txt
@@ -170,7 +170,14 @@
 set(LIBUNWIND_COMPILER    ${CMAKE_CXX_COMPILER})
 set(LIBUNWIND_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})
 set(LIBUNWIND_BINARY_DIR  ${CMAKE_CURRENT_BINARY_DIR})
-if (LLVM_LIBRARY_OUTPUT_INTDIR)
+
+string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+       ${PACKAGE_VERSION})
+
+if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
+  set(DEFAULT_INSTALL_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/)
+  set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LLVM_RUNTIMES_LIBDIR_SUFFIX})
+elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
 else()
   set(LIBUNWIND_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBUNWIND_LIBDIR_SUFFIX})
@@ -180,13 +187,9 @@
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
 
-set(LIBUNWIND_INSTALL_PREFIX "" CACHE STRING
+set(LIBUNWIND_INSTALL_PREFIX ${DEFAULT_INSTALL_PREFIX} CACHE STRING
     "Define libunwind destination prefix.")
 
-if (NOT LIBUNWIND_INSTALL_PREFIX MATCHES "^$|.*/")
-  message(FATAL_ERROR "LIBUNWIND_INSTALL_PREFIX has to end with \"/\".")
-endif()
-
 set(LIBUNWIND_C_FLAGS "")
 set(LIBUNWIND_CXX_FLAGS "")
 set(LIBUNWIND_COMPILE_FLAGS "")
Index: llvm/CMakeLists.txt
===================================================================
--- llvm/CMakeLists.txt
+++ llvm/CMakeLists.txt
@@ -584,6 +584,9 @@
 set(LLVM_TARGET_TRIPLE_ENV CACHE STRING "The name of environment variable to override default target. Disabled by blank.")
 mark_as_advanced(LLVM_TARGET_TRIPLE_ENV)
 
+set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR OFF CACHE BOOL
+  "Enable per-target runtimes directory")
+
 # All options referred to from HandleLLVMOptions have to be specified
 # BEFORE this include, otherwise options will not be correctly set on
 # first cmake run
Index: llvm/runtimes/CMakeLists.txt
===================================================================
--- llvm/runtimes/CMakeLists.txt
+++ llvm/runtimes/CMakeLists.txt
@@ -124,6 +124,9 @@
     set(LLVM_RUNTIMES_PREFIX "${LLVM_RUNTIMES_TARGET}/")
   endif()
 
+  string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+         ${PACKAGE_VERSION})
+
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
@@ -133,12 +136,6 @@
     # The subdirectories need to treat this as standalone builds
     set(${canon_name}_STANDALONE_BUILD On)
 
-    if(LLVM_RUNTIMES_TARGET)
-      if(NOT "${projName}" MATCHES "compiler-rt")
-        set(${canon_name}_INSTALL_PREFIX "lib/${LLVM_RUNTIMES_PREFIX}/" CACHE STRING "" FORCE)
-      endif()
-    endif()
-
     # Setting a variable to let sub-projects detect which other projects
     # will be included under here.
     set(HAVE_${canon_name} On)
@@ -153,15 +150,6 @@
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
-    if(LLVM_RUNTIMES_TARGET)
-      if(NOT "${projName}" MATCHES "compiler-rt")
-        set(LLVM_BINARY_DIR "${LLVM_LIBRARY_DIR}/${LLVM_RUNTIMES_PREFIX}")
-        set(LLVM_LIBDIR_SUFFIX "${LLVM_RUNTIMES_LIBDIR_SUFFIX}")
-        set(LLVM_LIBRARY_OUTPUT_INTDIR "${LLVM_LIBRARY_DIR}/${LLVM_RUNTIMES_PREFIX}lib${LLVM_RUNTIMES_LIBDIR_SUFFIX}")
-        set(LLVM_RUNTIME_OUTPUT_INTDIR "${LLVM_TOOLS_BINARY_DIR}/${LLVM_RUNTIMES_PREFIX}")
-      endif()
-    endif()
-
     # Between each sub-project we want to cache and clear the LIT properties
     set_property(GLOBAL PROPERTY LLVM_LIT_TESTSUITES)
     set_property(GLOBAL PROPERTY LLVM_LIT_PARAMS)
@@ -247,6 +235,8 @@
                              ${compiler_rt_path}/lib/builtins
                              CMAKE_ARGS -DLLVM_LIBRARY_OUTPUT_INTDIR=${LLVM_LIBRARY_DIR}
                                         -DLLVM_RUNTIME_OUTPUT_INTDIR=${LLVM_TOOLS_BINARY_DIR}
+                                        -DLLVM_DEFAULT_TARGET_TRIPLE=${TARGET_TRIPLE}
+                                        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
                                         -DCMAKE_C_COMPILER_TARGET=${TARGET_TRIPLE}
                                         -DCMAKE_ASM_COMPILER_TARGET=${TARGET_TRIPLE}
                                         -DCMAKE_C_COMPILER_WORKS=ON
@@ -278,6 +268,8 @@
                              ${compiler_rt_path}/lib/builtins
                              CMAKE_ARGS -DLLVM_LIBRARY_OUTPUT_INTDIR=${LLVM_LIBRARY_DIR}
                                         -DLLVM_RUNTIME_OUTPUT_INTDIR=${LLVM_TOOLS_BINARY_DIR}
+                                        -DLLVM_DEFAULT_TARGET_TRIPLE=${target}
+                                        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
                                         -DCMAKE_C_COMPILER_TARGET=${target}
                                         -DCMAKE_ASM_COMPILER_TARGET=${target}
                                         -DCMAKE_C_COMPILER_WORKS=ON
@@ -371,6 +363,8 @@
                              CMAKE_ARGS -DCOMPILER_RT_BUILD_BUILTINS=Off
                                         -DLLVM_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
                                         -DLLVM_LIBRARY_DIR=${LLVM_LIBRARY_DIR}
+                                        -DLLVM_DEFAULT_TARGET_TRIPLE=${TARGET_TRIPLE}
+                                        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
                                         -DCMAKE_C_COMPILER_TARGET=${TARGET_TRIPLE}
                                         -DCMAKE_CXX_COMPILER_TARGET=${TARGET_TRIPLE}
                                         -DCMAKE_ASM_COMPILER_TARGET=${TARGET_TRIPLE}
@@ -455,6 +449,8 @@
                              CMAKE_ARGS -DCOMPILER_RT_BUILD_BUILTINS=Off
                                         -DLLVM_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
                                         -DLLVM_LIBRARY_DIR=${LLVM_LIBRARY_DIR}
+                                        -DLLVM_DEFAULT_TARGET_TRIPLE=${target}
+                                        -DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
                                         -DCMAKE_C_COMPILER_TARGET=${target}
                                         -DCMAKE_CXX_COMPILER_TARGET=${target}
                                         -DCMAKE_ASM_COMPILER_TARGET=${target}