lib: Clean up float/fpu options

ARM ABIs now have a float field. This is used as a fallback to lessen
our use of `platform.gcc.float`. I didn't know what the MIPs convention
is so I kept using `platform.gcc.float` in that case.

lib/systems/examples.nix

@@ -11,21 +11,16 @@ rec {
 
   sheevaplug = rec {
     config = "armv5tel-unknown-linux-gnueabi";
-    float = "soft";
     platform = platforms.sheevaplug;
   };
 
   raspberryPi = rec {
     config = "armv6l-unknown-linux-gnueabihf";
-    float = "hard";
-    fpu = "vfp";
     platform = platforms.raspberrypi;
   };
 
   armv7l-hf-multiplatform = rec {
     config = "armv7a-unknown-linux-gnueabihf";
-    float = "hard";
-    fpu = "vfpv3-d16";
     platform = platforms.armv7l-hf-multiplatform;
   };
 
@@ -47,26 +42,24 @@ rec {
 
   pogoplug4 = rec {
     config = "armv5tel-unknown-linux-gnueabi";
-    float = "soft";
     platform = platforms.pogoplug4;
   };
 
   ben-nanonote = rec {
     config = "mipsel-unknown-linux-uclibc";
-    float = "soft";
     platform = {
       name = "ben_nanonote";
       kernelMajor = "2.6";
       kernelArch = "mips";
       gcc = {
         arch = "mips32";
+        float = "soft";
       };
     };
   };
 
   fuloongminipc = rec {
     config = "mipsel-unknown-linux-gnu";
-    float = "hard";
     platform = platforms.fuloong2f_n32;
   };
 

lib/systems/parse.nix

@@ -182,20 +182,24 @@ rec {
   types.abi = enum (attrValues abis);
 
   abis = setTypes types.openAbi {
-    android = {};
-    cygnus = {};
-    gnu = {};
-    msvc = {};
-    eabi = {};
-    androideabi = {};
-    gnueabi = {};
-    gnueabihf = {};
-    musleabi = {};
-    musleabihf = {};
-    musl = {};
-    uclibceabihf = {};
-    uclibceabi = {};
-    uclibc = {};
+    cygnus       = {};
+    msvc         = {};
+    eabi         = {};
+
+    androideabi  = {};
+    android      = {};
+
+    gnueabi      = { float = "soft"; };
+    gnueabihf    = { float = "hard"; };
+    gnu          = {};
+
+    musleabi     = { float = "soft"; };
+    musleabihf   = { float = "hard"; };
+    musl         = {};
+
+    uclibceabihf = { float = "soft"; };
+    uclibceabi   = { float = "hard"; };
+    uclibc       = {};
 
     unknown = {};
   };

lib/systems/platforms.nix

@@ -25,7 +25,6 @@ rec {
 
     gcc = {
       arch = "armv5te";
-      float = "soft";
     };
 
     kernelMajor = "2.6";
@@ -158,7 +157,6 @@ rec {
     kernelDTB = true; # Beyond 3.10
     gcc = {
       arch = "armv5te";
-      float = "soft";
     };
   };
 
@@ -336,7 +334,6 @@ rec {
     gcc = {
       cpu = "cortex-a9";
       fpu = "vfpv3";
-      float = "hard";
     };
   };
 
@@ -363,7 +360,6 @@ rec {
     gcc = {
       cpu = "cortex-a9";
       fpu = "neon";
-      float = "hard";
     };
   };
 
@@ -449,6 +445,7 @@ rec {
     kernelTarget = "vmlinux";
     gcc = {
       arch = "loongson2f";
+      float = "hard";
       abi = "n32";
     };
   };
@@ -498,7 +495,6 @@ rec {
       # and the above page suggests NEON is only an improvement with hand-written assembly.
       arch = "armv7-a";
       fpu = "vfpv3-d16";
-      float = "hard";
 
       # For Raspberry Pi the 2 the best would be:
       #   cpu = "cortex-a7";

pkgs/development/compilers/gcc/common/platform-flags.nix

@@ -2,11 +2,12 @@
 
 let
   p = targetPlatform.platform.gcc or {};
+  float = p.float or (targetPlatform.parsed.abi.float or null);
 in lib.concatLists [
   (lib.optional (p ? arch) "--with-arch=${p.arch}")
   (lib.optional (p ? cpu) "--with-cpu=${p.cpu}")
   (lib.optional (p ? abi) "--with-abi=${p.abi}")
   (lib.optional (p ? fpu) "--with-fpu=${p.fpu}")
-  (lib.optional (p ? float) "--with-float=${p.float}")
+  (lib.optional (float != null) "--with-float=${float}")
   (lib.optional (p ? mode) "--with-mode=${p.mode}")
 ]

pkgs/development/libraries/glibc/common.nix

@@ -127,7 +127,9 @@ stdenv.mkDerivation ({
     ] ++ lib.optionals withLinuxHeaders [
       "--enable-kernel=3.2.0" # can't get below with glibc >= 2.26
     ] ++ lib.optionals (cross != null) [
-      (if cross ? float && cross.float == "soft" then "--without-fp" else "--with-fp")
+      (if cross.platform.gcc.float or (cross.parsed.abi.float or "hard") == "soft"
+       then "--without-fp"
+       else "--with-fp")
     ] ++ lib.optionals (cross != null) [
       "--with-__thread"
     ] ++ lib.optionals (cross == null && stdenv.isAarch32) [