diff --git a/pkgs/development/compilers/llvm/4/clang/default.nix b/pkgs/development/compilers/llvm/4/clang/default.nix
index a90fbe6ae837..5bdd3731207e 100644
--- a/pkgs/development/compilers/llvm/4/clang/default.nix
+++ b/pkgs/development/compilers/llvm/4/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, release_version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, release_version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 }:
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/4/default.nix b/pkgs/development/compilers/llvm/4/default.nix
index 9651dbb72f4d..2f457880db10 100644
--- a/pkgs/development/compilers/llvm/4/default.nix
+++ b/pkgs/development/compilers/llvm/4/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -17,7 +17,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "1dhmp7ccfpr42bmvk3kp37ngjpf3a9m5d4kkpsn7d00hzi7fdl9m";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     llvm = callPackage ./llvm.nix {
@@ -29,12 +29,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -57,7 +57,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     stdenv = overrideCC stdenv buildLlvmTools.clang;
diff --git a/pkgs/development/compilers/llvm/4/libc++/default.nix b/pkgs/development/compilers/llvm/4/libc++/default.nix
index 0213741e3e06..264342701ae9 100644
--- a/pkgs/development/compilers/llvm/4/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/4/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version }:
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version }:
 
 stdenv.mkDerivation {
   pname = "libc++";
@@ -31,7 +31,7 @@ stdenv.mkDerivation {
   '' + lib.optionalString stdenv.hostPlatform.isMusl ''
     patchShebangs utils/cat_files.py
   '';
-  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python;
+  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/4/lldb.nix b/pkgs/development/compilers/llvm/4/lldb.nix
index 8adf11abddda..7f6231278e6c 100644
--- a/pkgs/development/compilers/llvm/4/lldb.nix
+++ b/pkgs/development/compilers/llvm/4/lldb.nix
@@ -9,7 +9,7 @@
 , libxml2
 , llvm
 , clang-unwrapped
-, python
+, python3
 , version
 , darwin
 }:
@@ -31,7 +31,7 @@ stdenv.mkDerivation {
       cmake/modules/LLDBStandalone.cmake
   '';
 
-  nativeBuildInputs = [ cmake python which swig ];
+  nativeBuildInputs = [ cmake python3 which swig ];
   buildInputs = [ ncurses zlib libedit libxml2 llvm ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.libobjc darwin.apple_sdk.libs.xpc darwin.apple_sdk.frameworks.Foundation darwin.bootstrap_cmds darwin.apple_sdk.frameworks.Carbon darwin.apple_sdk.frameworks.Cocoa ];
 
diff --git a/pkgs/development/compilers/llvm/4/llvm.nix b/pkgs/development/compilers/llvm/4/llvm.nix
index 317a5ea06f48..d5f640414861 100644
--- a/pkgs/development/compilers/llvm/4/llvm.nix
+++ b/pkgs/development/compilers/llvm/4/llvm.nix
@@ -2,7 +2,7 @@
 , fetch
 , fetchpatch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libxml2
@@ -40,8 +40,8 @@ stdenv.mkDerivation ({
   outputs = [ "out" ]
     ++ stdenv.lib.optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+  nativeBuildInputs = [ cmake python3 ]
+    ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
   buildInputs = [ libxml2 libffi ];
 
diff --git a/pkgs/development/compilers/llvm/5/clang/default.nix b/pkgs/development/compilers/llvm/5/clang/default.nix
index 6695609b8ecd..e391ce046dbc 100644
--- a/pkgs/development/compilers/llvm/5/clang/default.nix
+++ b/pkgs/development/compilers/llvm/5/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 }:
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/5/compiler-rt.nix b/pkgs/development/compilers/llvm/5/compiler-rt.nix
index c87b0f235961..0282591b6e20 100644
--- a/pkgs/development/compilers/llvm/5/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/5/compiler-rt.nix
@@ -1,11 +1,11 @@
-{ stdenv, version, fetch, cmake, python, llvm, libcxxabi }:
+{ stdenv, version, fetch, cmake, python3, llvm, libcxxabi }:
 with stdenv.lib;
 stdenv.mkDerivation {
   pname = "compiler-rt";
   inherit version;
   src = fetch "compiler-rt" "0ipd4jdxpczgr2w6lzrabymz6dhzj69ywmyybjjc1q397zgrvziy";
 
-  nativeBuildInputs = [ cmake python llvm ];
+  nativeBuildInputs = [ cmake python3 llvm ];
   buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin libcxxabi;
 
   configureFlags = [
diff --git a/pkgs/development/compilers/llvm/5/default.nix b/pkgs/development/compilers/llvm/5/default.nix
index 6807240df81e..05f4dbf6aa06 100644
--- a/pkgs/development/compilers/llvm/5/default.nix
+++ b/pkgs/development/compilers/llvm/5/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -16,7 +16,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "018b3fiwah8f8br5i26qmzh6sjvzchpn358sn8v079m49f2jldm3";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
     mkExtraBuildCommands = cc: ''
       rsrc="$out/resource-root"
       mkdir "$rsrc"
@@ -36,12 +36,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -74,7 +74,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     compiler-rt = callPackage ./compiler-rt.nix {};
diff --git a/pkgs/development/compilers/llvm/5/libc++/default.nix b/pkgs/development/compilers/llvm/5/libc++/default.nix
index 03d8a2085d0b..b02e09a83a81 100644
--- a/pkgs/development/compilers/llvm/5/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/5/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version }:
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version }:
 
 stdenv.mkDerivation {
   pname = "libc++";
@@ -25,7 +25,7 @@ stdenv.mkDerivation {
   '' + lib.optionalString stdenv.hostPlatform.isMusl ''
     patchShebangs utils/cat_files.py
   '';
-  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python;
+  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/5/lldb.nix b/pkgs/development/compilers/llvm/5/lldb.nix
index cce44c7e50f9..a91a7e4354ef 100644
--- a/pkgs/development/compilers/llvm/5/lldb.nix
+++ b/pkgs/development/compilers/llvm/5/lldb.nix
@@ -9,7 +9,7 @@
 , libxml2
 , llvm
 , clang-unwrapped
-, python
+, python3
 , version
 , darwin
 }:
@@ -30,7 +30,7 @@ stdenv.mkDerivation {
       cmake/modules/LLDBStandalone.cmake
   '';
 
-  nativeBuildInputs = [ cmake python which swig ];
+  nativeBuildInputs = [ cmake python3 which swig ];
   buildInputs = [ ncurses zlib libedit libxml2 llvm ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.libobjc darwin.apple_sdk.libs.xpc darwin.apple_sdk.frameworks.Foundation darwin.bootstrap_cmds darwin.apple_sdk.frameworks.Carbon darwin.apple_sdk.frameworks.Cocoa ];
 
diff --git a/pkgs/development/compilers/llvm/5/llvm.nix b/pkgs/development/compilers/llvm/5/llvm.nix
index d26af8438e73..cd26b7d17a92 100644
--- a/pkgs/development/compilers/llvm/5/llvm.nix
+++ b/pkgs/development/compilers/llvm/5/llvm.nix
@@ -2,7 +2,7 @@
 , fetch
 , fetchpatch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libxml2
@@ -37,8 +37,8 @@ stdenv.mkDerivation ({
   outputs = [ "out" "python" ]
     ++ stdenv.lib.optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+  nativeBuildInputs = [ cmake python3 ]
+    ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
   buildInputs = [ libxml2 libffi ];
 
diff --git a/pkgs/development/compilers/llvm/6/clang/default.nix b/pkgs/development/compilers/llvm/6/clang/default.nix
index d093379b3c99..9374fc0bda9f 100644
--- a/pkgs/development/compilers/llvm/6/clang/default.nix
+++ b/pkgs/development/compilers/llvm/6/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 }:
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/6/compiler-rt.nix b/pkgs/development/compilers/llvm/6/compiler-rt.nix
index 4cf79e79569c..b3b6e86fc525 100644
--- a/pkgs/development/compilers/llvm/6/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/6/compiler-rt.nix
@@ -1,11 +1,11 @@
-{ stdenv, version, fetch, cmake, python, llvm, libcxxabi }:
+{ stdenv, version, fetch, cmake, python3, llvm, libcxxabi }:
 with stdenv.lib;
 stdenv.mkDerivation {
   pname = "compiler-rt";
   inherit version;
   src = fetch "compiler-rt" "1fcr3jn24yr8lh36nc0c4ikli4744i2q9m1ik67p1jymwwaixkgl";
 
-  nativeBuildInputs = [ cmake python llvm ];
+  nativeBuildInputs = [ cmake python3 llvm ];
   buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin libcxxabi;
 
   configureFlags = [
diff --git a/pkgs/development/compilers/llvm/6/default.nix b/pkgs/development/compilers/llvm/6/default.nix
index ae51c19ec728..d4745930ed3f 100644
--- a/pkgs/development/compilers/llvm/6/default.nix
+++ b/pkgs/development/compilers/llvm/6/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -16,7 +16,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "1w8ml7fyn4vyxmy59n2qm4r1k1kgwgwkaldp6m45fdv4g0kkfbhd";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
     mkExtraBuildCommands = cc: ''
       rsrc="$out/resource-root"
       mkdir "$rsrc"
@@ -36,12 +36,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -74,7 +74,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     compiler-rt = callPackage ./compiler-rt.nix {};
diff --git a/pkgs/development/compilers/llvm/6/libc++/default.nix b/pkgs/development/compilers/llvm/6/libc++/default.nix
index 658068cbfaff..831c6c9c7002 100644
--- a/pkgs/development/compilers/llvm/6/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/6/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version }:
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version }:
 
 stdenv.mkDerivation {
   pname = "libc++";
@@ -25,7 +25,7 @@ stdenv.mkDerivation {
   '' + lib.optionalString stdenv.hostPlatform.isMusl ''
     patchShebangs utils/cat_files.py
   '';
-  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python;
+  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/6/lldb.nix b/pkgs/development/compilers/llvm/6/lldb.nix
index d3db8082c963..30d72d944264 100644
--- a/pkgs/development/compilers/llvm/6/lldb.nix
+++ b/pkgs/development/compilers/llvm/6/lldb.nix
@@ -9,7 +9,7 @@
 , libxml2
 , llvm
 , clang-unwrapped
-, python
+, python3
 , version
 , darwin
 }:
@@ -30,7 +30,7 @@ stdenv.mkDerivation {
       cmake/modules/LLDBStandalone.cmake
   '';
 
-  nativeBuildInputs = [ cmake python which swig ];
+  nativeBuildInputs = [ cmake python3 which swig ];
   buildInputs = [ ncurses zlib libedit libxml2 llvm ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.libobjc darwin.apple_sdk.libs.xpc darwin.apple_sdk.frameworks.Foundation darwin.bootstrap_cmds darwin.apple_sdk.frameworks.Carbon darwin.apple_sdk.frameworks.Cocoa ];
 
diff --git a/pkgs/development/compilers/llvm/6/llvm.nix b/pkgs/development/compilers/llvm/6/llvm.nix
index c6d2c09c2df6..8faab6b94a92 100644
--- a/pkgs/development/compilers/llvm/6/llvm.nix
+++ b/pkgs/development/compilers/llvm/6/llvm.nix
@@ -1,7 +1,7 @@
 { stdenv
 , fetch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libxml2
@@ -40,8 +40,8 @@ stdenv.mkDerivation ({
   outputs = [ "out" "python" ]
     ++ optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ optional enableManpages python.pkgs.sphinx;
+  nativeBuildInputs = [ cmake python3 ]
+    ++ optional enableManpages python3.pkgs.sphinx;
 
   buildInputs = [ libxml2 libffi ];
 
diff --git a/pkgs/development/compilers/llvm/7/clang/default.nix b/pkgs/development/compilers/llvm/7/clang/default.nix
index 5ac9a7a2672a..cc5dcfc160bc 100644
--- a/pkgs/development/compilers/llvm/7/clang/default.nix
+++ b/pkgs/development/compilers/llvm/7/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 , enablePolly ? false # TODO: get this info from llvm (passthru?)
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/7/compiler-rt.nix b/pkgs/development/compilers/llvm/7/compiler-rt.nix
index a7d4bcb86962..ae98940adeab 100644
--- a/pkgs/development/compilers/llvm/7/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/7/compiler-rt.nix
@@ -1,10 +1,10 @@
-{ stdenv, version, fetch, cmake, python, llvm, libcxxabi }:
+{ stdenv, version, fetch, cmake, python3, llvm, libcxxabi }:
 stdenv.mkDerivation {
   pname = "compiler-rt";
   inherit version;
   src = fetch "compiler-rt" "1n48p8gjarihkws0i2bay5w9bdwyxyxxbpwyng7ba58jb30dlyq5";
 
-  nativeBuildInputs = [ cmake python llvm ];
+  nativeBuildInputs = [ cmake python3 llvm ];
   buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin libcxxabi;
 
   NIX_CFLAGS_COMPILE = [
diff --git a/pkgs/development/compilers/llvm/7/default.nix b/pkgs/development/compilers/llvm/7/default.nix
index 621a246225d7..f5dbea58a7db 100644
--- a/pkgs/development/compilers/llvm/7/default.nix
+++ b/pkgs/development/compilers/llvm/7/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -16,7 +16,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "0lb4kdh7j2fhfz8kd6iv5df7m3pikiryk1vvwsf87spc90n09q0w";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
     mkExtraBuildCommands = cc: ''
       rsrc="$out/resource-root"
       mkdir "$rsrc"
@@ -42,12 +42,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -126,7 +126,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     compiler-rt = callPackage ./compiler-rt.nix {
diff --git a/pkgs/development/compilers/llvm/7/libc++/default.nix b/pkgs/development/compilers/llvm/7/libc++/default.nix
index f6f9970d7a6e..f2cdd2f6f5fa 100644
--- a/pkgs/development/compilers/llvm/7/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/7/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version
 , enableShared ? ! stdenv.hostPlatform.isMusl }:
 
 stdenv.mkDerivation {
@@ -24,7 +24,7 @@ stdenv.mkDerivation {
   '' + lib.optionalString stdenv.hostPlatform.isMusl ''
     patchShebangs utils/cat_files.py
   '';
-  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python;
+  nativeBuildInputs = [ cmake ] ++ stdenv.lib.optional stdenv.hostPlatform.isMusl python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/7/lldb.nix b/pkgs/development/compilers/llvm/7/lldb.nix
index 44687ead4d1c..ace6ae812fde 100644
--- a/pkgs/development/compilers/llvm/7/lldb.nix
+++ b/pkgs/development/compilers/llvm/7/lldb.nix
@@ -10,7 +10,7 @@
 , llvm
 , clang-unwrapped
 , perl
-, python
+, python3
 , version
 , darwin
 }:
@@ -21,7 +21,7 @@ stdenv.mkDerivation {
 
   src = fetch "lldb" "0klsscg1sczc4nw2l53xggi969k361cng2sjjrfp3bv4g5x14s4v";
 
-  nativeBuildInputs = [ cmake perl python which swig ];
+  nativeBuildInputs = [ cmake perl python3 which swig ];
   buildInputs = [ ncurses zlib libedit libxml2 llvm ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.libobjc darwin.apple_sdk.libs.xpc darwin.apple_sdk.frameworks.Foundation darwin.bootstrap_cmds darwin.apple_sdk.frameworks.Carbon darwin.apple_sdk.frameworks.Cocoa ];
 
diff --git a/pkgs/development/compilers/llvm/7/llvm.nix b/pkgs/development/compilers/llvm/7/llvm.nix
index c56bbfd0eab9..62be8bbedabe 100644
--- a/pkgs/development/compilers/llvm/7/llvm.nix
+++ b/pkgs/development/compilers/llvm/7/llvm.nix
@@ -2,7 +2,7 @@
 , fetch
 , fetchpatch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libpfm
@@ -48,8 +48,8 @@ in stdenv.mkDerivation ({
   outputs = [ "out" "python" ]
     ++ optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ optional enableManpages python.pkgs.sphinx;
+  nativeBuildInputs = [ cmake python3 ]
+    ++ optional enableManpages python3.pkgs.sphinx;
 
   buildInputs = [ libxml2 libffi ]
     ++ optional enablePFM libpfm; # exegesis
diff --git a/pkgs/development/compilers/llvm/8/clang/default.nix b/pkgs/development/compilers/llvm/8/clang/default.nix
index 8c540e45b286..8601f6d06809 100644
--- a/pkgs/development/compilers/llvm/8/clang/default.nix
+++ b/pkgs/development/compilers/llvm/8/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 , enablePolly ? false # TODO: get this info from llvm (passthru?)
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/8/compiler-rt.nix b/pkgs/development/compilers/llvm/8/compiler-rt.nix
index 344ff7256755..9c0829146f72 100644
--- a/pkgs/development/compilers/llvm/8/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/8/compiler-rt.nix
@@ -1,10 +1,10 @@
-{ stdenv, version, fetch, cmake, python, llvm, libcxxabi }:
+{ stdenv, version, fetch, cmake, python3, llvm, libcxxabi }:
 stdenv.mkDerivation {
   pname = "compiler-rt";
   inherit version;
   src = fetch "compiler-rt" "0dqqf8f930l8gag4d9qjgn1n0pj0nbv2anviqqhdi1rkhas8z0hi";
 
-  nativeBuildInputs = [ cmake python llvm ];
+  nativeBuildInputs = [ cmake python3 llvm ];
   buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin libcxxabi;
 
   NIX_CFLAGS_COMPILE = [
diff --git a/pkgs/development/compilers/llvm/8/default.nix b/pkgs/development/compilers/llvm/8/default.nix
index 36d7a14142b4..8b916e1cda7d 100644
--- a/pkgs/development/compilers/llvm/8/default.nix
+++ b/pkgs/development/compilers/llvm/8/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -16,7 +16,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "1qf3097bc5ia8p6cpmbx985rjr3yaah5s8fc0nv7pw742yv7jw8q";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
     mkExtraBuildCommands = cc: ''
       rsrc="$out/resource-root"
       mkdir "$rsrc"
@@ -42,12 +42,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -162,7 +162,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     compiler-rt = callPackage ./compiler-rt.nix ({} //
diff --git a/pkgs/development/compilers/llvm/8/libc++/default.nix b/pkgs/development/compilers/llvm/8/libc++/default.nix
index 8ec1c419748d..883d9c8776f3 100644
--- a/pkgs/development/compilers/llvm/8/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/8/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version
 , enableShared ? true }:
 
 stdenv.mkDerivation {
@@ -25,7 +25,7 @@ stdenv.mkDerivation {
     patchShebangs utils/cat_files.py
   '';
   nativeBuildInputs = [ cmake ]
-    ++ stdenv.lib.optional (stdenv.hostPlatform.isMusl || stdenv.hostPlatform.isWasi) python;
+    ++ stdenv.lib.optional (stdenv.hostPlatform.isMusl || stdenv.hostPlatform.isWasi) python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/8/lldb.nix b/pkgs/development/compilers/llvm/8/lldb.nix
index 254933c82a09..75be5b993df3 100644
--- a/pkgs/development/compilers/llvm/8/lldb.nix
+++ b/pkgs/development/compilers/llvm/8/lldb.nix
@@ -9,7 +9,7 @@
 , libxml2
 , llvm
 , clang-unwrapped
-, python
+, python3
 , version
 , darwin
 }:
@@ -30,7 +30,7 @@ stdenv.mkDerivation {
       cmake/modules/LLDBStandalone.cmake
   '';
 
-  nativeBuildInputs = [ cmake python which swig ];
+  nativeBuildInputs = [ cmake python3 which swig ];
   buildInputs = [ ncurses zlib libedit libxml2 llvm ]
     ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.libobjc darwin.apple_sdk.libs.xpc darwin.apple_sdk.frameworks.Foundation darwin.bootstrap_cmds darwin.apple_sdk.frameworks.Carbon darwin.apple_sdk.frameworks.Cocoa ];
 
diff --git a/pkgs/development/compilers/llvm/8/llvm.nix b/pkgs/development/compilers/llvm/8/llvm.nix
index df3d6e796aa0..18946f5d640b 100644
--- a/pkgs/development/compilers/llvm/8/llvm.nix
+++ b/pkgs/development/compilers/llvm/8/llvm.nix
@@ -1,7 +1,7 @@
 { stdenv
 , fetch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libpfm
@@ -46,8 +46,8 @@ in stdenv.mkDerivation ({
   outputs = [ "out" "python" ]
     ++ optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ optionals enableManpages [ python.pkgs.sphinx python.pkgs.recommonmark ];
+  nativeBuildInputs = [ cmake python3 ]
+    ++ optionals enableManpages [ python3.pkgs.sphinx python3.pkgs.recommonmark ];
 
   buildInputs = [ libxml2 libffi ]
     ++ optional enablePFM libpfm; # exegesis
diff --git a/pkgs/development/compilers/llvm/9/clang/default.nix b/pkgs/development/compilers/llvm/9/clang/default.nix
index 1b779b118a7f..5f89c3dc3b71 100644
--- a/pkgs/development/compilers/llvm/9/clang/default.nix
+++ b/pkgs/development/compilers/llvm/9/clang/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python
+{ stdenv, fetch, cmake, libxml2, llvm, version, clang-tools-extra_src, python3
 , fixDarwinDylibNames
 , enableManpages ? false
 , enablePolly ? false # TODO: get this info from llvm (passthru?)
@@ -19,8 +19,8 @@ let
       mv clang-tools-extra-* $sourceRoot/tools/extra
     '';
 
-    nativeBuildInputs = [ cmake python ]
-      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
+    nativeBuildInputs = [ cmake python3 ]
+      ++ stdenv.lib.optional enableManpages python3.pkgs.sphinx;
 
     buildInputs = [ libxml2 llvm ]
       ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
diff --git a/pkgs/development/compilers/llvm/9/compiler-rt.nix b/pkgs/development/compilers/llvm/9/compiler-rt.nix
index 75d0614b5142..037953bb23d8 100644
--- a/pkgs/development/compilers/llvm/9/compiler-rt.nix
+++ b/pkgs/development/compilers/llvm/9/compiler-rt.nix
@@ -1,10 +1,10 @@
-{ stdenv, version, fetch, cmake, python, llvm, libcxxabi }:
+{ stdenv, version, fetch, cmake, python3, llvm, libcxxabi }:
 stdenv.mkDerivation rec {
   pname = "compiler-rt";
   inherit version;
   src = fetch pname "0xwh79g3zggdabxgnd0bphry75asm1qz7mv3hcqihqwqr6aspgy2";
 
-  nativeBuildInputs = [ cmake python llvm ];
+  nativeBuildInputs = [ cmake python3 llvm ];
   buildInputs = stdenv.lib.optional stdenv.hostPlatform.isDarwin libcxxabi;
 
   NIX_CFLAGS_COMPILE = [
diff --git a/pkgs/development/compilers/llvm/9/default.nix b/pkgs/development/compilers/llvm/9/default.nix
index c9e8ce91f0ce..38ab7794018f 100644
--- a/pkgs/development/compilers/llvm/9/default.nix
+++ b/pkgs/development/compilers/llvm/9/default.nix
@@ -1,5 +1,5 @@
 { lowPrio, newScope, pkgs, stdenv, cmake, libstdcxxHook
-, libxml2, python, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
+, libxml2, python3, isl, fetchurl, overrideCC, wrapCCWith, wrapBintoolsWith
 , buildLlvmTools # tools, but from the previous stage, for cross
 , targetLlvmLibraries # libraries, but from the next stage, for cross
 }:
@@ -16,7 +16,7 @@ let
   clang-tools-extra_src = fetch "clang-tools-extra" "01vgzd4k1q93nfs8gyl83mjlc4x0qsgfqw32lacbjzdxg0mdfvxj";
 
   tools = stdenv.lib.makeExtensible (tools: let
-    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (tools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
     mkExtraBuildCommands = cc: ''
       rsrc="$out/resource-root"
       mkdir "$rsrc"
@@ -42,12 +42,12 @@ let
 
     llvm-manpages = lowPrio (tools.llvm.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     clang-manpages = lowPrio (tools.clang-unwrapped.override {
       enableManpages = true;
-      python = pkgs.python;  # don't use python-boot
+      python3 = pkgs.python3;  # don't use python-boot
     });
 
     libclang = tools.clang-unwrapped.lib;
@@ -162,7 +162,7 @@ let
   });
 
   libraries = stdenv.lib.makeExtensible (libraries: let
-    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python isl release_version version fetch; });
+    callPackage = newScope (libraries // buildLlvmTools // { inherit stdenv cmake libxml2 python3 isl release_version version fetch; });
   in {
 
     compiler-rt = callPackage ./compiler-rt.nix ({} //
diff --git a/pkgs/development/compilers/llvm/9/libc++/default.nix b/pkgs/development/compilers/llvm/9/libc++/default.nix
index 1166c7bd76c9..9e3525574d5c 100644
--- a/pkgs/development/compilers/llvm/9/libc++/default.nix
+++ b/pkgs/development/compilers/llvm/9/libc++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetch, cmake, python, libcxxabi, fixDarwinDylibNames, version
+{ lib, stdenv, fetch, cmake, python3, libcxxabi, fixDarwinDylibNames, version
 , enableShared ? true }:
 
 stdenv.mkDerivation {
@@ -21,7 +21,7 @@ stdenv.mkDerivation {
     patchShebangs utils/cat_files.py
   '';
   nativeBuildInputs = [ cmake ]
-    ++ stdenv.lib.optional (stdenv.hostPlatform.isMusl || stdenv.hostPlatform.isWasi) python;
+    ++ stdenv.lib.optional (stdenv.hostPlatform.isMusl || stdenv.hostPlatform.isWasi) python3;
 
   buildInputs = [ libcxxabi ] ++ lib.optional stdenv.isDarwin fixDarwinDylibNames;
 
diff --git a/pkgs/development/compilers/llvm/9/lldb.nix b/pkgs/development/compilers/llvm/9/lldb.nix
index 64f111502cc5..506fc1c3e505 100644
--- a/pkgs/development/compilers/llvm/9/lldb.nix
+++ b/pkgs/development/compilers/llvm/9/lldb.nix
@@ -9,7 +9,7 @@
 , libxml2
 , llvm
 , clang-unwrapped
-, python
+, python3
 , version
 , darwin
 , lit
@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
 
   patches = [ ./lldb-procfs.patch ];
 
-  nativeBuildInputs = [ cmake python which swig lit ];
+  nativeBuildInputs = [ cmake python3 which swig lit ];
   buildInputs = [
     ncurses
     zlib
diff --git a/pkgs/development/compilers/llvm/9/llvm.nix b/pkgs/development/compilers/llvm/9/llvm.nix
index acd3ec92897f..c0e750dc31c0 100644
--- a/pkgs/development/compilers/llvm/9/llvm.nix
+++ b/pkgs/development/compilers/llvm/9/llvm.nix
@@ -1,7 +1,7 @@
 { stdenv
 , fetch
 , cmake
-, python
+, python3
 , libffi
 , libbfd
 , libpfm
@@ -46,8 +46,8 @@ in stdenv.mkDerivation (rec {
   outputs = [ "out" "python" ]
     ++ optional enableSharedLibraries "lib";
 
-  nativeBuildInputs = [ cmake python ]
-    ++ optionals enableManpages [ python.pkgs.sphinx python.pkgs.recommonmark ];
+  nativeBuildInputs = [ cmake python3 ]
+    ++ optionals enableManpages [ python3.pkgs.sphinx python3.pkgs.recommonmark ];
 
   buildInputs = [ libxml2 libffi ]
     ++ optional enablePFM libpfm; # exegesis
diff --git a/pkgs/development/interpreters/python/cpython/2.7/boot.nix b/pkgs/development/interpreters/python/cpython/2.7/boot.nix
deleted file mode 100644
index 0b9ddc0bb345..000000000000
--- a/pkgs/development/interpreters/python/cpython/2.7/boot.nix
+++ /dev/null
@@ -1,103 +0,0 @@
-{ stdenv, fetchurl, configd, CF, coreutils }:
-
-with stdenv.lib;
-
-let
-
-  mkPaths = paths: {
-    C_INCLUDE_PATH = makeSearchPathOutput "dev" "include" paths;
-    LIBRARY_PATH = makeLibraryPath paths;
-  };
-
-in
-
-stdenv.mkDerivation rec {
-  pname = "python-boot";
-  version = "2.7.12";
-  libPrefix = "python2.7";
-
-  src = fetchurl {
-    url = "https://www.python.org/ftp/python/2.7.12/Python-${version}.tar.xz";
-    sha256 = "0y7rl603vmwlxm6ilkhc51rx2mfj14ckcz40xxgs0ljnvlhp30yp";
-  };
-
-  inherit (mkPaths buildInputs) C_INCLUDE_PATH LIBRARY_PATH;
-
-  LDFLAGS = optionalString (!stdenv.isDarwin) "-lgcc_s";
-  NIX_CFLAGS_COMPILE = optionalString stdenv.isDarwin "-msse2";
-
-  buildInputs = optionals stdenv.isDarwin [ CF configd ];
-
-  patches =
-    [ # Look in C_INCLUDE_PATH and LIBRARY_PATH for stuff.
-      ./search-path.patch
-
-      # Python recompiles a Python if the mtime stored *in* the
-      # pyc/pyo file differs from the mtime of the source file.  This
-      # doesn't work in Nix because Nix changes the mtime of files in
-      # the Nix store to 1.  So treat that as a special case.
-      ./nix-store-mtime.patch
-
-      # patch python to put zero timestamp into pyc
-      # if DETERMINISTIC_BUILD env var is set
-      ./deterministic-build.patch
-    ];
-
-  # Hack hack hack to stop shit from failing from a missing _scproxy on Darwin. Since
-  # we only use this python for bootstrappy things, it doesn't really matter if it
-  # doesn't have perfect proxy support in urllib :) this just makes it fall back on env
-  # vars instead of attempting to read the proxy configuration automatically, so not a
-  # huge loss even if for whatever reason we did want proxy support.
-  postPatch = ''
-    substituteInPlace Lib/urllib.py --replace "if sys.platform == 'darwin'" "if False"
-  '';
-
-  DETERMINISTIC_BUILD = 1;
-
-  preConfigure = ''
-      # Purity.
-      for i in /usr /sw /opt /pkg; do
-        substituteInPlace ./setup.py --replace $i /no-such-path
-      done
-    '' + optionalString (stdenv ? cc && stdenv.cc.libc != null) ''
-      for i in Lib/plat-*/regen; do
-        substituteInPlace $i --replace /usr/include/ ${stdenv.cc.libc}/include/
-      done
-    '' + optionalString stdenv.isDarwin ''
-      substituteInPlace configure --replace '`/usr/bin/arch`' '"i386"'
-      substituteInPlace Lib/multiprocessing/__init__.py \
-        --replace 'os.popen(comm)' 'os.popen("${coreutils}/bin/nproc")'
-    '';
-
-  configureFlags = [ "--enable-shared" "--with-threads" "--enable-unicode=ucs4" ]
-    ++ optionals stdenv.isCygwin [ "ac_cv_func_bind_textdomain_codeset=yes" ]
-    ++ optionals stdenv.isDarwin [ "--disable-toolbox-glue" ];
-
-  postInstall =
-    ''
-      ln -s $out/share/man/man1/{python2.7.1.gz,python.1.gz}
-
-      rm "$out"/lib/python*/plat-*/regen # refers to glibc.dev
-    '';
-
-  enableParallelBuilding = true;
-
-  passthru.pkgs = builtins.throw "python-boot does not support packages, this package is only intended for bootstrapping." {};
-
-  meta = {
-    homepage = http://python.org;
-    description = "A high-level dynamically-typed programming language";
-    longDescription = ''
-      Python is a remarkably powerful dynamic programming language that
-      is used in a wide variety of application domains. Some of its key
-      distinguishing features include: clear, readable syntax; strong
-      introspection capabilities; intuitive object orientation; natural
-      expression of procedural code; full modularity, supporting
-      hierarchical packages; exception-based error handling; and very
-      high level dynamic data types.
-    '';
-    license = stdenv.lib.licenses.psfl;
-    platforms = stdenv.lib.platforms.all;
-    maintainers = with stdenv.lib.maintainers; [ lnl7 domenkozar ];
-  };
-}
diff --git a/pkgs/development/interpreters/python/cpython/2.7/default.nix b/pkgs/development/interpreters/python/cpython/2.7/default.nix
index e6b3dff433b3..77b37c5f5c39 100644
--- a/pkgs/development/interpreters/python/cpython/2.7/default.nix
+++ b/pkgs/development/interpreters/python/cpython/2.7/default.nix
@@ -11,7 +11,7 @@
 , tcl ? null, tk ? null, tix ? null, xlibsWrapper ? null, libX11 ? null, x11Support ? false
 , zlib
 , self
-, CF, configd, coreutils
+, configd, coreutils
 , python-setup-hook
 # Some proprietary libs assume UCS2 unicode, especially on darwin :(
 , ucsEncoding ? 4
@@ -180,7 +180,7 @@ let
     ++ optional stdenv.hostPlatform.isCygwin expat
     ++ [ db gdbm ncurses sqlite readline ]
     ++ optionals x11Support [ tcl tk xlibsWrapper libX11 ]
-    ++ optionals stdenv.isDarwin ([ CF ] ++ optional (configd != null) configd);
+    ++ optional (stdenv.isDarwin && configd != null) configd;
   nativeBuildInputs =
     optionals (stdenv.hostPlatform != stdenv.buildPlatform)
     [ buildPackages.stdenv.cc buildPackages.python ];
diff --git a/pkgs/development/interpreters/python/cpython/default.nix b/pkgs/development/interpreters/python/cpython/default.nix
index e75bd0a09875..70eff43daf5c 100644
--- a/pkgs/development/interpreters/python/cpython/default.nix
+++ b/pkgs/development/interpreters/python/cpython/default.nix
@@ -11,7 +11,7 @@
 , tcl ? null, tk ? null, tix ? null, libX11 ? null, xorgproto ? null, x11Support ? false
 , zlib
 , self
-, CF, configd
+, configd
 , python-setup-hook
 , nukeReferences
 # For the Python package set
@@ -57,10 +57,10 @@ let
     pythonForBuild
   ];
 
-  buildInputs = filter (p: p != null) [
+  buildInputs = filter (p: p != null) ([
     zlib bzip2 expat lzma libffi gdbm sqlite readline ncurses openssl ]
     ++ optionals x11Support [ tcl tk libX11 xorgproto ]
-    ++ optionals stdenv.isDarwin [ CF configd ];
+    ++ optionals stdenv.isDarwin [ configd ]);
 
   hasDistutilsCxxPatch = !(stdenv.cc.isGNU or false);
 
diff --git a/pkgs/development/interpreters/python/default.nix b/pkgs/development/interpreters/python/default.nix
index caf2e13bdf62..367a6194ecff 100644
--- a/pkgs/development/interpreters/python/default.nix
+++ b/pkgs/development/interpreters/python/default.nix
@@ -57,7 +57,7 @@ in {
       suffix = "";
     };
     sha256 = "0hds28cg226m8j8sr394nm9yc4gxhvlv109w0avsf2mxrlrz0hsd";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -70,7 +70,7 @@ in {
       suffix = "";
     };
     sha256 = "0jdh9pvx6m6lfz2liwvvhn7vks7qrysqgwn517fkpxb77b33fjn2";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -83,7 +83,7 @@ in {
       suffix = "";
     };
     sha256 = "1pj0mz1xl27khi250p29c0y99vxg662js8zp71aprkf8i8wkr0qa";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -96,7 +96,7 @@ in {
       suffix = "";
     };
     sha256 = "0gskry19ylw91p38pdq36qcgk6h3x5i4ia0ik977kw2943kwr8jm";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -109,7 +109,7 @@ in {
       suffix = "";
     };
     sha256 = "1s4lwn5vzsajlc88m6hkghsvnjw4d00l2dsgng0m2w6vyqbl32bm";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -122,7 +122,7 @@ in {
       suffix = "a2";
     };
     sha256 = "02a301bdcldin05ksdg8xw8xr6gdkpf73p0cabvn9rdl6yhkr3q8";
-    inherit (darwin) CF configd;
+    inherit (darwin) configd;
     inherit passthruFun;
   };
 
@@ -136,6 +136,7 @@ in {
     ncurses = null;
     gdbm = null;
     sqlite = null;
+    configd = null;
     stripConfig = true;
     stripIdlelib = true;
     stripTests = true;
diff --git a/pkgs/development/tools/build-managers/ninja/default.nix b/pkgs/development/tools/build-managers/ninja/default.nix
index 1c90bcc3a9f8..7001510d52d6 100644
--- a/pkgs/development/tools/build-managers/ninja/default.nix
+++ b/pkgs/development/tools/build-managers/ninja/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, fetchpatch, python, buildDocs ? true, asciidoc, docbook_xml_dtd_45, docbook_xsl, libxslt, re2c }:
+{ stdenv, fetchFromGitHub, fetchpatch, python3, buildDocs ? true, asciidoc, docbook_xml_dtd_45, docbook_xsl, libxslt, re2c }:
 
 with stdenv.lib;
 
@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
       sha256 = "0zsg46jflsh644jccrcgyfalr7fkzrv041kyi8644nyk923gcrl9";
     })
     # https://github.com/ninja-build/ninja/issues/1510 - fix w/musl, possibly BSDs?
-    # 
+    #
     (fetchpatch {
       name = "fix-issue-1510.patch";
       url = https://github.com/makepost/ninja/commit/567815df38a2ff54ad7478a90bd75c91e434236a.patch;
@@ -29,7 +29,7 @@ stdenv.mkDerivation rec {
     })
   ];
 
-  nativeBuildInputs = [ python re2c ] ++ optionals buildDocs [ asciidoc docbook_xml_dtd_45 docbook_xsl libxslt.bin ];
+  nativeBuildInputs = [ python3 re2c ] ++ optionals buildDocs [ asciidoc docbook_xml_dtd_45 docbook_xsl libxslt.bin ];
 
   buildPhase = ''
     python configure.py --bootstrap
diff --git a/pkgs/os-specific/darwin/apple-sdk/default.nix b/pkgs/os-specific/darwin/apple-sdk/default.nix
index c3914777c6dc..aef7341e5e9f 100644
--- a/pkgs/os-specific/darwin/apple-sdk/default.nix
+++ b/pkgs/os-specific/darwin/apple-sdk/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, xar, cpio, pkgs, python, pbzx, lib }:
+{ stdenv, fetchurl, xar, cpio, pkgs, python3, pbzx, lib }:
 
 let
   # sadly needs to be exported because security_tool needs it
@@ -16,7 +16,7 @@ let
       sha256 = "13xq34sb7383b37hwy076gnhf96prpk1b4087p87xnwswxbrisih";
     };
 
-    buildInputs = [ xar cpio python pbzx ];
+    nativeBuildInputs = [ xar cpio python3 pbzx ];
 
     outputs = [ "out" "dev" "man" ];
 
diff --git a/pkgs/os-specific/darwin/apple-source-releases/xnu/default.nix b/pkgs/os-specific/darwin/apple-source-releases/xnu/default.nix
index afa5dc1c08cb..da2d0c5dc7bf 100644
--- a/pkgs/os-specific/darwin/apple-source-releases/xnu/default.nix
+++ b/pkgs/os-specific/darwin/apple-source-releases/xnu/default.nix
@@ -1,9 +1,11 @@
 { appleDerivation, lib, bootstrap_cmds, bison, flex
-, gnum4, unifdef, perl, python
+, gnum4, unifdef, perl, python3
 , headersOnly ? true }:
 
 appleDerivation ({
-  nativeBuildInputs = [ bootstrap_cmds bison flex gnum4 unifdef perl python ];
+  nativeBuildInputs = [ bootstrap_cmds bison flex gnum4 unifdef perl python3 ];
+
+  patches = [ ./python3.patch ];
 
   postPatch = ''
     substituteInPlace Makefile \
diff --git a/pkgs/os-specific/darwin/apple-source-releases/xnu/python3.patch b/pkgs/os-specific/darwin/apple-source-releases/xnu/python3.patch
new file mode 100644
index 000000000000..10778406c8e0
--- /dev/null
+++ b/pkgs/os-specific/darwin/apple-source-releases/xnu/python3.patch
@@ -0,0 +1,41 @@
+diff --git a/bsd/kern/makekdebugevents.py b/bsd/kern/makekdebugevents.py
+index 73b2db4..d354ba0 100755
+--- a/bsd/kern/makekdebugevents.py
++++ b/bsd/kern/makekdebugevents.py
+@@ -5,7 +5,7 @@
+ # named kd_events[] or these mappings.
+ # Required to generate a header file used by DEVELOPMENT and DEBUG kernels.
+ #
+- 
++
+ import sys
+ import re
+ 
+@@ -21,18 +21,18 @@ code_table = []
+ # scan file to generate internal table
+ with open(trace_code_file, 'rt') as codes:
+     for line in codes:
+-	m = id_name_pattern.match(line)
+-	if m:
++        m = id_name_pattern.match(line)
++    if m:
+             code_table += [(int(m.group(1),base=16), m.group(2))]
+ 
+ # emit typedef:
+-print "typedef struct {"
+-print "        uint32_t   id;"
+-print "        const char *name;"
+-print "} kd_event_t;"
++print("typedef struct {")
++print("        uint32_t   id;")
++print("        const char *name;")
++print("} kd_event_t;")
+ # emit structure declaration and sorted initialization:
+-print "kd_event_t kd_events[] = {"
++print("kd_event_t kd_events[] = {")
+ for mapping in sorted(code_table, key=lambda x: x[0]):
+-        print "        {0x%x, \"%s\"}," % mapping
+-print "};"
++        print("        {0x%x, \"%s\"}," % mapping)
++print("};")
+ 
diff --git a/pkgs/os-specific/darwin/iproute2mac/default.nix b/pkgs/os-specific/darwin/iproute2mac/default.nix
index be8554983074..e82636fce1f2 100644
--- a/pkgs/os-specific/darwin/iproute2mac/default.nix
+++ b/pkgs/os-specific/darwin/iproute2mac/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, darwin, python }:
+{ stdenv, fetchFromGitHub, darwin, python2 }:
 
 stdenv.mkDerivation rec {
   version = "1.2.1";
@@ -11,11 +11,11 @@ stdenv.mkDerivation rec {
     sha256 = "1n6la7blbxza2m79cpnywsavhzsdv4gzdxrkly4dppyidjg6jy1h";
   };
 
-  buildInputs = [ python ];
+  buildInputs = [ python2 ];
 
   postPatch = ''
     substituteInPlace src/ip.py \
-      --replace /usr/bin/python ${python}/bin/python \
+      --replace /usr/bin/python ${python2}/bin/python \
       --replace /sbin/ifconfig ${darwin.network_cmds}/bin/ifconfig \
       --replace /sbin/route ${darwin.network_cmds}/bin/route \
       --replace /usr/sbin/netstat ${darwin.network_cmds}/bin/netstat \
diff --git a/pkgs/os-specific/darwin/libtapi/default.nix b/pkgs/os-specific/darwin/libtapi/default.nix
index 2af1c5db2e32..182d1db3bfd5 100644
--- a/pkgs/os-specific/darwin/libtapi/default.nix
+++ b/pkgs/os-specific/darwin/libtapi/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, cmake, python, clang_6 }:
+{ lib, stdenv, fetchFromGitHub, cmake, python3, clang_6 }:
 
 stdenv.mkDerivation {
   name = "libtapi-1000.10.8";
@@ -9,7 +9,7 @@ stdenv.mkDerivation {
     sha256 = "1a19h39a48agvnmal99n9j1fjadiqwib7hfzmn342wmgh9z3vk0g";
   };
 
-  nativeBuildInputs = [ cmake python ];
+  nativeBuildInputs = [ cmake python3 ];
   buildInputs = [ clang_6.cc ];
 
   preConfigure = ''
diff --git a/pkgs/os-specific/darwin/swift-corelibs/corefoundation.nix b/pkgs/os-specific/darwin/swift-corelibs/corefoundation.nix
index 4f2f84b3c0a5..059cb70bfbd5 100644
--- a/pkgs/os-specific/darwin/swift-corelibs/corefoundation.nix
+++ b/pkgs/os-specific/darwin/swift-corelibs/corefoundation.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, fetchurl, python, ninja, libxml2, objc4, ICU, curl }:
+{ stdenv, fetchFromGitHub, fetchurl, ninja, python3, curl, libxml2, objc4, ICU }:
 
 let
   # 10.12 adds a new sysdir.h that our version of CF in the main derivation depends on, but
@@ -20,8 +20,8 @@ stdenv.mkDerivation {
     sha256 = "17kpql0f27xxz4jjw84vpas5f5sn4vdqwv10g151rc3rswbwln1z";
   };
 
-  nativeBuildInputs = [ ninja python ];
-  buildInputs = [ libxml2 objc4 ICU curl ];
+  nativeBuildInputs = [ ninja python3 ];
+  buildInputs = [ curl libxml2 objc4 ICU ];
 
   sourceRoot = "source/CoreFoundation";
 
diff --git a/pkgs/stdenv/darwin/default.nix b/pkgs/stdenv/darwin/default.nix
index 86a6e33c9424..f73fca48b7a7 100644
--- a/pkgs/stdenv/darwin/default.nix
+++ b/pkgs/stdenv/darwin/default.nix
@@ -190,13 +190,10 @@ in rec {
         useSharedLibraries = false;
       };
 
-      python = super.callPackage ../../development/interpreters/python/cpython/2.7/boot.nix {
-        CF = null;  # use CoreFoundation from bootstrap-tools
-        configd = null;
-      };
-      python2 = self.python;
+      python3 = super.python3Minimal;
 
       ninja = super.ninja.override { buildDocs = false; };
+
       darwin = super.darwin // {
         cctools = super.darwin.cctools.override {
           enableTapiSupport = false;
@@ -218,11 +215,11 @@ in rec {
   stage2 = prevStage: let
     persistent = self: super: with prevStage; {
       inherit
-        zlib patchutils m4 scons flex perl bison unifdef unzip openssl python
+        zlib patchutils m4 scons flex perl bison unifdef unzip openssl python3
         libxml2 gettext sharutils gmp libarchive ncurses pkg-config libedit groff
         openssh sqlite sed serf openldap db cyrus-sasl expat apr-util subversion xz
         findfreetype libssh curl cmake autoconf automake libtool ed cpio coreutils
-        libssh2 nghttp2 libkrb5 python2 ninja;
+        libssh2 nghttp2 libkrb5 ninja;
 
       darwin = super.darwin // {
         inherit (darwin)
@@ -252,11 +249,11 @@ in rec {
   stage3 = prevStage: let
     persistent = self: super: with prevStage; {
       inherit
-        patchutils m4 scons flex perl bison unifdef unzip openssl python
+        patchutils m4 scons flex perl bison unifdef unzip openssl python3
         gettext sharutils libarchive pkg-config groff bash subversion
         openssh sqlite sed serf openldap db cyrus-sasl expat apr-util
         findfreetype libssh curl cmake autoconf automake libtool cpio
-        libssh2 nghttp2 libkrb5 python2 ninja;
+        libssh2 nghttp2 libkrb5 ninja;
 
       # Avoid pulling in a full python and its extra dependencies for the llvm/clang builds.
       libxml2 = super.libxml2.override { pythonSupport = false; };
@@ -302,7 +299,7 @@ in rec {
   stage4 = prevStage: let
     persistent = self: super: with prevStage; {
       inherit
-        gnumake gzip gnused bzip2 gawk ed xz patch bash
+        gnumake gzip gnused bzip2 gawk ed xz patch bash python3
         ncurses libffi zlib gmp pcre gnugrep
         coreutils findutils diffutils patchutils ninja;
 
@@ -332,7 +329,7 @@ in rec {
         libxml2-nopython = super.libxml2.override { pythonSupport = false; };
         CF = super.darwin.CF.override {
           libxml2 = libxml2-nopython;
-          python = prevStage.python;
+          python3 = prevStage.python3;
         };
       };
     };
@@ -365,17 +362,6 @@ in rec {
         });
       in { inherit tools libraries; } // tools // libraries);
 
-      # N.B: the important thing here is to ensure that python == python2
-      # == python27 or you get weird issues with inconsistent package sets.
-      # In a particularly subtle bug, I overrode python2 instead of python27
-      # here, and it caused gnome-doc-utils to complain about:
-      # "PyThreadState_Get: no current thread". This is because Python gets
-      # really unhappy if you have Python A which loads a native python lib
-      # which was linked against Python B, which in our case was happening
-      # because we didn't override python "deeply enough". Anyway, this works
-      # and I'm just leaving this blurb here so people realize why it matters
-      python27 = super.python27.override { CF = prevStage.darwin.CF; };
-
       darwin = super.darwin // {
         inherit (darwin) dyld ICU Libsystem libiconv;
       } // lib.optionalAttrs (super.stdenv.targetPlatform == localSystem) {
@@ -438,7 +424,8 @@ in rec {
       inherit cc;
 
       darwin = super.darwin // {
-        xnu = super.darwin.xnu.override { python = super.python.override { configd = null; }; };
+        inherit (prevStage.darwin) CF;
+        xnu = super.darwin.xnu.override { inherit (prevStage) python3; };
       };
     });
   };
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index f5082bd39263..c8e9d44d75d1 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -13112,7 +13112,7 @@ in
   libxmi = callPackage ../development/libraries/libxmi { };
 
   libxml2 = callPackage ../development/libraries/libxml2 {
-    python = if stdenv.isDarwin then python2 else python3;
+    python = python3;
   };
 
   libxml2Python = let