diff --git a/pkgs/development/compilers/llvm/6/clang/default.nix b/pkgs/development/compilers/llvm/6/clang/default.nix
index 5ef97ef7d82e..a5e639cde6df 100644
--- a/pkgs/development/compilers/llvm/6/clang/default.nix
+++ b/pkgs/development/compilers/llvm/6/clang/default.nix
@@ -9,7 +9,7 @@ let
     name = "clang-${version}";
 
     unpackPhase = ''
-      unpackFile ${fetch "cfe" "1mrj0ig9x5dxvglmkyw6i8yb9hvznywqn2g6lqaw7a5fhjjdq0x2"}
+      unpackFile ${fetch "cfe" "1j9pzl71r1bnp0dsxj33p5pvl6njg0bf2yyi9vhci13nw7y71i0x"}
       mv cfe-${version}* clang
       sourceRoot=$PWD/clang
       unpackFile ${clang-tools-extra_src}
diff --git a/pkgs/development/compilers/llvm/6/default.nix b/pkgs/development/compilers/llvm/6/default.nix
index 3fa53f7281e4..c49f9e3d7340 100644
--- a/pkgs/development/compilers/llvm/6/default.nix
+++ b/pkgs/development/compilers/llvm/6/default.nix
@@ -7,15 +7,15 @@ let
   callPackage = newScope (self // { inherit stdenv cmake libxml2 python2 isl release_version version fetch; });
 
   release_version = "6.0.0";
-  version = "6.0.0rc1"; # differentiating these is important for rc's
+  version = "6.0.0rc2"; # differentiating these is important for rc's
 
   fetch = name: sha256: fetchurl {
-    url = "http://prereleases.llvm.org/${release_version}/rc1/${name}-${version}.src.tar.xz";
+    url = "http://prereleases.llvm.org/${release_version}/rc2/${name}-${version}.src.tar.xz";
     inherit sha256;
   };
 
-  compiler-rt_src = fetch "compiler-rt" "08dwlax5sfmpzwfbzdwig9hbmrqzlq2332rb5yh0l5xrp0y5869z";
-  clang-tools-extra_src = fetch "clang-tools-extra" "1rj4b6cqn05s2b3qiw7iadc8a1hrn4vs6g06nwxmqwpx3790dqyn";
+  compiler-rt_src = fetch "compiler-rt" "1ajk4iykgppc3wxij552m0qnj4rx3z1yyxj2yxhffwpsf973x68j";
+  clang-tools-extra_src = fetch "clang-tools-extra" "0vhaq3yq97w82jvq3w6ccvciwg7zp78b7s1246f3xdai6ijgk8g3";
 
   # Add man output without introducing extra dependencies.
   overrideManOutput = drv:
diff --git a/pkgs/development/compilers/llvm/6/libc++/default.nix b/pkgs/development/compilers/llvm/6/libc++/default.nix
index e0294430a267..cd9a7c548fc4 100644
--- a/pkgs/development/compilers/llvm/6/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/6/libc++/default.nix
@@ -3,7 +3,7 @@
 stdenv.mkDerivation rec {
   name = "libc++-${version}";
 
-  src = fetch "libcxx" "0l026xx364a6zbx8sbd3280wbag0pkmj342v8zh1lg0661w52l8d";
+  src = fetch "libcxx" "0rpgd25v4h7dgvmqjnksgjmss3lhqzah57lfirpskdllcj9cfa9z";
 
   postUnpack = ''
     unpackFile ${libcxxabi.src}
diff --git a/pkgs/development/compilers/llvm/6/libc++abi.nix b/pkgs/development/compilers/llvm/6/libc++abi.nix
index 3ffd5637ee0d..0a32e1e33b59 100644
--- a/pkgs/development/compilers/llvm/6/libc++abi.nix
+++ b/pkgs/development/compilers/llvm/6/libc++abi.nix
@@ -3,7 +3,7 @@
 stdenv.mkDerivation {
   name = "libc++abi-${version}";
 
-  src = fetch "libcxxabi" "0kmfmxm3iph9l1ndj2z7gj52n8bmy0rnnxzidfbliays2qzbwrsk";
+  src = fetch "libcxxabi" "10rc7r33bhz4fflnqdian9jvgf1r85p9qxkkgr78wxc7680f0ccx";
 
   nativeBuildInputs = [ cmake ];
   buildInputs = stdenv.lib.optional (!stdenv.isDarwin && !stdenv.isFreeBSD) libunwind;
diff --git a/pkgs/development/compilers/llvm/6/lld.nix b/pkgs/development/compilers/llvm/6/lld.nix
index 79bdacbf90cb..f52d5e70fef2 100644
--- a/pkgs/development/compilers/llvm/6/lld.nix
+++ b/pkgs/development/compilers/llvm/6/lld.nix
@@ -10,7 +10,7 @@
 stdenv.mkDerivation {
   name = "lld-${version}";
 
-  src = fetch "lld" "1yzq762bh375sskjgkcr0vqlhlii2br86z8wi2jbxmml0pj0xn99";
+  src = fetch "lld" "0wj8rwd4bqh32p03hksy9bngv5pwrwmlxglslm8clwlxrc2rkb1f";
 
   nativeBuildInputs = [ cmake ];
   buildInputs = [ llvm libxml2 ];
diff --git a/pkgs/development/compilers/llvm/6/lldb.nix b/pkgs/development/compilers/llvm/6/lldb.nix
index fa9bde903f6c..8890f154b4f3 100644
--- a/pkgs/development/compilers/llvm/6/lldb.nix
+++ b/pkgs/development/compilers/llvm/6/lldb.nix
@@ -17,7 +17,7 @@
 stdenv.mkDerivation {
   name = "lldb-${version}";
 
-  src = fetch "lldb" "1a0bmk0p4rclk0wvfg2ga4wkqp8lm6l3wx6g4g4dgiavd4bgsgl4";
+  src = fetch "lldb" "118yj804rgg5fwdj9j2yydamgfqx7c585ahiyap26x09cz5g2l1v";
 
   postPatch = ''
     # Fix up various paths that assume llvm and clang are installed in the same place
diff --git a/pkgs/development/compilers/llvm/6/llvm.nix b/pkgs/development/compilers/llvm/6/llvm.nix
index 4cfef8044b5e..75d096416c18 100644
--- a/pkgs/development/compilers/llvm/6/llvm.nix
+++ b/pkgs/development/compilers/llvm/6/llvm.nix
@@ -22,7 +22,7 @@
 }:
 
 let
-  src = fetch "llvm" "0dsik1l6jshd617fh4qs1373s6dfkq4gsjhyf6zq2qb6kyisy2vd";
+  src = fetch "llvm" "1jnk30b7csdldar88pws2b000k3n1484k6gg2sxgz2fc6j7ldkzn";
 
   # Used when creating a version-suffixed symlink of libLLVM.dylib
   shortVersion = with stdenv.lib;
diff --git a/pkgs/development/compilers/llvm/6/openmp.nix b/pkgs/development/compilers/llvm/6/openmp.nix
index f4c2a3f160a0..dc1b9b32544f 100644
--- a/pkgs/development/compilers/llvm/6/openmp.nix
+++ b/pkgs/development/compilers/llvm/6/openmp.nix
@@ -10,7 +10,7 @@
 stdenv.mkDerivation {
   name = "openmp-${version}";
 
-  src = fetch "openmp" "0infci57hr89nxgs3v34z87kaqdw9pdkr6apyywkb8av032rhhpf";
+  src = fetch "openmp" "1jz7i7gw8yazkn9hxsnq2lw9mj60g4wff4529yhx956jq1g1mr0k";
 
   nativeBuildInputs = [ cmake perl ];
   buildInputs = [ llvm ];