diff --git a/pkgs/development/compilers/llvm/4/clang/default.nix b/pkgs/development/compilers/llvm/4/clang/default.nix
index c0a33f03e0f2..88eafe983d3e 100644
--- a/pkgs/development/compilers/llvm/4/clang/default.nix
+++ b/pkgs/development/compilers/llvm/4/clang/default.nix
@@ -6,7 +6,7 @@ let
     name = "clang-${version}";
 
     unpackPhase = ''
-      unpackFile ${fetch "cfe" "062n17mfsn85dx3qy1qvq8rfxi7hcbr2nj70v2dah3xmy28i3yaq"}
+      unpackFile ${fetch "cfe" "12n99m60aa680cir3ql56s1jsv6lp61hq4w9rabf4c6vpn7gi9ff"}
       mv cfe-${version}* clang
       sourceRoot=$PWD/clang
       unpackFile ${clang-tools-extra_src}
diff --git a/pkgs/development/compilers/llvm/4/default.nix b/pkgs/development/compilers/llvm/4/default.nix
index aed77b7513ad..999ff858d020 100644
--- a/pkgs/development/compilers/llvm/4/default.nix
+++ b/pkgs/development/compilers/llvm/4/default.nix
@@ -3,18 +3,15 @@ let
   callPackage = newScope (self // { inherit stdenv isl release_version version fetch; });
 
   release_version = "4.0.0";
-  rc = "rc4";
-  version = "${release_version}${rc}";
+  version = release_version; # differentiating these is important for rc's
 
   fetch = name: sha256: fetchurl {
-    url = "http://llvm.org/pre-releases/${release_version}/${rc}/${name}-${version}.src.tar.xz";
-    # Once 4 is released, use this instead:
-    # url = "http://llvm.org/releases/${release-version}/${name}-${version}.src.tar.xz";
+    url = "http://llvm.org/releases/${release_version}/${name}-${version}.src.tar.xz";
     inherit sha256;
   };
 
-  compiler-rt_src = fetch "compiler-rt" "1bxz2z9mxbx7211xfgsn5inwvpz53d1cqg76h8166dsli27xwkjm";
-  clang-tools-extra_src = fetch "clang-tools-extra" "0zkgnnv3srqxf44q4a5n3wpizf71mlq8w5rnwfwhdx777k94s5nx";
+  compiler-rt_src = fetch "compiler-rt" "059ipqq27gd928ay06f1ck3vw6y5h5z4zd766x8k0k7jpqimpwnk";
+  clang-tools-extra_src = fetch "clang-tools-extra" "16bwckgcxfn56mbqjlxi7fxja0zm9hjfa6s3ncm3dz98n5zd7ds1";
 
   self = {
     llvm = callPackage ./llvm.nix {
diff --git a/pkgs/development/compilers/llvm/4/libc++/default.nix b/pkgs/development/compilers/llvm/4/libc++/default.nix
index 753aded54ff7..8e2c8eaa1768 100644
--- a/pkgs/development/compilers/llvm/4/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/4/libc++/default.nix
@@ -3,7 +3,7 @@
 stdenv.mkDerivation rec {
   name = "libc++-${version}";
 
-  src = fetch "libcxx" "052fc91y8084830ajfm8nkc0vghafhnfl7l89b68qsyz3ra93i3l";
+  src = fetch "libcxx" "15ngfcjc3pjakpwfq7d4n546jj0rgfdv5rpb1qv9xgv9mp236kag";
 
   postUnpack = ''
     unpackFile ${libcxxabi.src}
diff --git a/pkgs/development/compilers/llvm/4/libc++abi.nix b/pkgs/development/compilers/llvm/4/libc++abi.nix
index 23269f605f09..559b6b26bc52 100644
--- a/pkgs/development/compilers/llvm/4/libc++abi.nix
+++ b/pkgs/development/compilers/llvm/4/libc++abi.nix
@@ -3,7 +3,7 @@
 stdenv.mkDerivation {
   name = "libc++abi-${version}";
 
-  src = fetch "libcxxabi" "02z8d0q42wfmnnd0rd1yg2x4y50rfrv1k9rq00a86b6803dc7p45";
+  src = fetch "libcxxabi" "1n416kv27anabg9jsw6331r28ic30xk46p381lx2vbb2jrhwpafw";
 
   buildInputs = [ cmake ] ++ stdenv.lib.optional (!stdenv.isDarwin && !stdenv.isFreeBSD) libunwind;
 
diff --git a/pkgs/development/compilers/llvm/4/lld.nix b/pkgs/development/compilers/llvm/4/lld.nix
index e62e50b2d316..549fa863c151 100644
--- a/pkgs/development/compilers/llvm/4/lld.nix
+++ b/pkgs/development/compilers/llvm/4/lld.nix
@@ -10,7 +10,7 @@
 stdenv.mkDerivation {
   name = "lld-${version}";
 
-  src = fetch "lld" "00wy4qczh4s6g49sbfmyk21845zx5qc2qpm39bznqz8ynpnh4phc";
+  src = fetch "lld" "00km1qawk146pyjqa6aphcdzgkzrmg6cgk0ikg4661ffp5bn9q1k";
 
   buildInputs = [ cmake llvm ];
 
diff --git a/pkgs/development/compilers/llvm/4/lldb.nix b/pkgs/development/compilers/llvm/4/lldb.nix
index 4fec3ad1a894..6e6fdf012dd6 100644
--- a/pkgs/development/compilers/llvm/4/lldb.nix
+++ b/pkgs/development/compilers/llvm/4/lldb.nix
@@ -17,7 +17,7 @@
 stdenv.mkDerivation {
   name = "lldb-${version}";
 
-  src = fetch "lldb" "14dy1j48nw10w8brkpmla2vjjwfr1mrsl9wfabjfx1j85ywp3h69";
+  src = fetch "lldb" "0g83hbw1r4gd0z8hlph9i34xs6dlcc69vz3h2bqwkhb2qq2qzg9d";
 
   patchPhase = ''
     # Fix up various paths that assume llvm and clang are installed in the same place
diff --git a/pkgs/development/compilers/llvm/4/llvm.nix b/pkgs/development/compilers/llvm/4/llvm.nix
index 1470e7d510fa..ac3fc6790d58 100644
--- a/pkgs/development/compilers/llvm/4/llvm.nix
+++ b/pkgs/development/compilers/llvm/4/llvm.nix
@@ -21,7 +21,7 @@
 }:
 
 let
-  src = fetch "llvm" "1ljb5y5wgypk3sy8zcd5qdgsm5hw8vl7cy6874mbf4gnk9k809b1";
+  src = fetch "llvm" "1giklnw71wzsgbqg9wb5x7dxnbj39m6zpfvskvzvhwvfz4fm244d";
   shlib = if stdenv.isDarwin then "dylib" else "so";
 
   # Used when creating a version-suffixed symlink of libLLVM.dylib
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 86058822f2a2..014eb5d96d17 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4782,7 +4782,7 @@ with pkgs;
 
   clang = llvmPackages.clang;
 
-  clang_4 = lowPrio llvmPackages_4.clang;
+  clang_4  = llvmPackages_4.clang;
   clang_39 = llvmPackages_39.clang;
   clang_38 = llvmPackages_38.clang;
   clang_37 = llvmPackages_37.clang;
@@ -5338,13 +5338,13 @@ with pkgs;
 
   lizardfs = callPackage ../tools/filesystems/lizardfs { };
 
-  lld = lowPrio llvmPackages_4.lld;
+  lld = llvmPackages_4.lld;
 
   lldb = llvmPackages.lldb;
 
   llvm = llvmPackages.llvm;
 
-  llvm_4 = lowPrio llvmPackages_4.llvm;
+  llvm_4  = llvmPackages_4.llvm;
   llvm_39 = llvmPackages_39.llvm;
   llvm_38 = llvmPackages_38.llvm;
   llvm_37 = llvmPackages_37.llvm;