diff --git a/pkgs/development/compilers/llvm/4/default.nix b/pkgs/development/compilers/llvm/4/default.nix
index 562f9e3457dd4..3405ee27112d7 100644
--- a/pkgs/development/compilers/llvm/4/default.nix
+++ b/pkgs/development/compilers/llvm/4/default.nix
@@ -1,6 +1,6 @@
 { lowPrio, newScope, stdenv, targetPlatform, cmake, libstdcxxHook
 , libxml2, python2, isl, fetchurl, overrideCC, wrapCC, ccWrapperFun
-, darwin
+, darwin, hostLLVM
 }:
 
 let
@@ -23,7 +23,7 @@ let
     drv // { man = drv-manpages.out; /*outputs = drv.outputs ++ ["man"];*/ };
 
   llvm = callPackage ./llvm.nix {
-    inherit compiler-rt_src stdenv;
+    inherit compiler-rt_src stdenv hostLLVM;
   };
 
   clang-unwrapped = callPackage ./clang {
diff --git a/pkgs/development/compilers/llvm/4/llvm.nix b/pkgs/development/compilers/llvm/4/llvm.nix
index bc8453f743ade..709c8db846537 100644
--- a/pkgs/development/compilers/llvm/4/llvm.nix
+++ b/pkgs/development/compilers/llvm/4/llvm.nix
@@ -17,6 +17,7 @@
 , enableManpages ? false
 , enableSharedLibraries ? true
 , darwin
+, hostLLVM
 }:
 
 let
@@ -40,7 +41,8 @@ in stdenv.mkDerivation (rec {
     ++ stdenv.lib.optional enableSharedLibraries "lib";
 
   nativeBuildInputs = [ cmake python ]
-    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx
+    ++ stdenv.lib.optional (stdenv.buildPlatform != stdenv.hostPlatform) hostLLVM;
 
   buildInputs = [ libxml2 libffi ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ libcxxabi ];
@@ -122,6 +124,10 @@ in stdenv.mkDerivation (rec {
     "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
     "-DLLVM_DEFAULT_TARGET_TRIPLE=${stdenv.targetPlatform.config}"
     "-DTARGET_TRIPLE=${stdenv.targetPlatform.config}"
+  ]
+  ++ stdenv.lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
+    "-DCMAKE_CROSSCOMPILING=True"
+    "-DLLVM_TABLEGEN=${hostLLVM}/bin/llvm-tblgen"
   ];
 
   postBuild = ''
diff --git a/pkgs/development/compilers/llvm/5/default.nix b/pkgs/development/compilers/llvm/5/default.nix
index 13e1d2308f8c6..e4eac9d9f57ec 100644
--- a/pkgs/development/compilers/llvm/5/default.nix
+++ b/pkgs/development/compilers/llvm/5/default.nix
@@ -1,6 +1,6 @@
 { lowPrio, newScope, stdenv, targetPlatform, cmake, libstdcxxHook
 , libxml2, python2, isl, fetchurl, overrideCC, wrapCC, ccWrapperFun
-, darwin
+, darwin, hostLLVM
 }:
 
 let
@@ -23,7 +23,7 @@ let
     drv // { man = drv-manpages.out; /*outputs = drv.outputs ++ ["man"];*/ };
 
   llvm = callPackage ./llvm.nix {
-    inherit compiler-rt_src stdenv;
+    inherit compiler-rt_src stdenv hostLLVM;
   };
 
   clang-unwrapped = callPackage ./clang {
diff --git a/pkgs/development/compilers/llvm/5/llvm.nix b/pkgs/development/compilers/llvm/5/llvm.nix
index ac575a0bf7aa5..8c7129af7b949 100644
--- a/pkgs/development/compilers/llvm/5/llvm.nix
+++ b/pkgs/development/compilers/llvm/5/llvm.nix
@@ -17,6 +17,7 @@
 , enableManpages ? false
 , enableSharedLibraries ? true
 , darwin
+, hostLLVM
 }:
 
 let
@@ -40,7 +41,9 @@ in stdenv.mkDerivation (rec {
     ++ stdenv.lib.optional enableSharedLibraries "lib";
 
   nativeBuildInputs = [ cmake python ]
-    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx
+    ++ stdenv.lib.optional (stdenv.buildPlatform != stdenv.hostPlatform)
+                           hostLLVM;
 
   buildInputs = [ libxml2 libffi ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ libcxxabi ];
@@ -115,6 +118,10 @@ in stdenv.mkDerivation (rec {
     "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
     "-DLLVM_DEFAULT_TARGET_TRIPLE=${stdenv.targetPlatform.config}"
     "-DTARGET_TRIPLE=${stdenv.targetPlatform.config}"
+  ]
+  ++ stdenv.lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
+    "-DCMAKE_CROSSCOMPILING=True"
+    "-DLLVM_TABLEGEN=${hostLLVM}/bin/llvm-tblgen"
   ];
 
   postBuild = ''
@@ -148,7 +155,9 @@ in stdenv.mkDerivation (rec {
     ln -s $lib/lib/libLLVM.dylib $lib/lib/libLLVM-${release_version}.dylib
   '';
 
-  doCheck = stdenv.isLinux && (!stdenv.isi686);
+  doCheck = stdenv.isLinux
+         && (!stdenv.isi686)
+         && (stdenv.buildPlatform == stdenv.hostPlatform);
 
   checkTarget = "check-all";
 
diff --git a/pkgs/development/compilers/llvm/6/default.nix b/pkgs/development/compilers/llvm/6/default.nix
index cfa9e9e15fcf1..58bc3da43d8a5 100644
--- a/pkgs/development/compilers/llvm/6/default.nix
+++ b/pkgs/development/compilers/llvm/6/default.nix
@@ -1,6 +1,6 @@
 { lowPrio, newScope, stdenv, targetPlatform, cmake, libstdcxxHook
 , libxml2, python2, isl, fetchurl, overrideCC, wrapCC, ccWrapperFun
-, darwin
+, darwin, hostLLVM
 }:
 
 let
@@ -23,7 +23,7 @@ let
     drv // { man = drv-manpages.out; /*outputs = drv.outputs ++ ["man"];*/ };
 
   llvm = callPackage ./llvm.nix {
-    inherit compiler-rt_src stdenv;
+    inherit compiler-rt_src stdenv hostLLVM;
   };
 
   clang-unwrapped = callPackage ./clang {
diff --git a/pkgs/development/compilers/llvm/6/llvm.nix b/pkgs/development/compilers/llvm/6/llvm.nix
index 7cb3e88c2f85d..22c41e3bfb9d2 100644
--- a/pkgs/development/compilers/llvm/6/llvm.nix
+++ b/pkgs/development/compilers/llvm/6/llvm.nix
@@ -18,6 +18,7 @@
 , enableSharedLibraries ? true
 , enableWasm ? true
 , darwin
+, hostLLVM
 }:
 
 let
@@ -41,7 +42,8 @@ in stdenv.mkDerivation (rec {
     ++ stdenv.lib.optional enableSharedLibraries "lib";
 
   nativeBuildInputs = [ cmake python ]
-    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx
+    ++ stdenv.lib.optional (stdenv.buildPlatform != stdenv.hostPlatform) hostLLVM;
 
   buildInputs = [ libxml2 libffi ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ libcxxabi ];
@@ -114,8 +116,13 @@ in stdenv.mkDerivation (rec {
     "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
     "-DLLVM_DEFAULT_TARGET_TRIPLE=${stdenv.targetPlatform.config}"
     "-DTARGET_TRIPLE=${stdenv.targetPlatform.config}"
-  ] ++ stdenv.lib.optional enableWasm
-   "-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly"
+  ]
+  ++ stdenv.lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform)[
+    "-DCMAKE_CROSSCOMPILING=True"
+    "-DLLVM_TABLEGEN=${hostLLVM}/bin/llvm-tblgen"
+  ]
+  ++ stdenv.lib.optional enableWasm
+    "-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly"
   ;
 
   postBuild = ''
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 1129a984d2711..a6c44796af33d 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -6708,12 +6708,14 @@ with pkgs;
 
   llvmPackages_4 = callPackage ../development/compilers/llvm/4 ({
     inherit (stdenvAdapters) overrideCC;
+    hostLLVM = buildPackages.llvmPackages_4.llvm;
   } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
     stdenv = overrideCC stdenv gcc6;
   });
 
   llvmPackages_5 = callPackage ../development/compilers/llvm/5 ({
     inherit (stdenvAdapters) overrideCC;
+    hostLLVM = buildPackages.llvmPackages_5.llvm;
   } // stdenv.lib.optionalAttrs stdenv.isDarwin {
     cmake = cmake.override {
       isBootstrap = true;
@@ -6727,6 +6729,7 @@ with pkgs;
 
   llvmPackages_6 = callPackage ../development/compilers/llvm/6 ({
     inherit (stdenvAdapters) overrideCC;
+    hostLLVM = buildPackages.llvmPackages_6.llvm;
   } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
     stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
   });