lib/systems: Support FreeBSD

A tricky thing about FreeBSD is that there is no stable ABI across
versions. That means that putting in the version as part of the config
string is paramount.

We have a parsed represenation that separates name versus version to
accomplish this. We include FreeBSD versions 12 and 13 to demonstrate
how it works.

7 files changed, 26 insertions, 11 deletions

diff --git a/doc/stdenv/meta.chapter.md b/doc/stdenv/meta.chapter.md
index a83aa0bd90f..f4d8ed2919d 100644
--- a/doc/stdenv/meta.chapter.md
+++ b/doc/stdenv/meta.chapter.md
@@ -44,8 +44,8 @@ $ nix-env -qa hello --json
                 "mips32-linux",
                 "x86_64-darwin",
                 "i686-cygwin",
-                "i686-freebsd",
-                "x86_64-freebsd",
+                "i686-freebsd13",
+                "x86_64-freebsd13",
                 "i686-openbsd",
                 "x86_64-openbsd"
             ],
diff --git a/lib/systems/default.nix b/lib/systems/default.nix
index 233174d4083..24f90b4565e 100644
--- a/lib/systems/default.nix
+++ b/lib/systems/default.nix
@@ -47,9 +47,10 @@ rec {
         else if final.isUClibc              then "uclibc"
         else if final.isAndroid             then "bionic"
         else if final.isLinux /* default */ then "glibc"
+        else if final.isFreeBSD             then "fblibc"
+        else if final.isNetBSD              then "nblibc"
         else if final.isAvr                 then "avrlibc"
         else if final.isNone                then "newlib"
-        else if final.isNetBSD              then "nblibc"
         # TODO(@Ericson2314) think more about other operating systems
         else                                     "native/impure";
       # Choose what linker we wish to use by default. Someday we might also
diff --git a/lib/systems/doubles.nix b/lib/systems/doubles.nix
index 709b67607f7..23a44d02e85 100644
--- a/lib/systems/doubles.nix
+++ b/lib/systems/doubles.nix
@@ -13,7 +13,7 @@ let
     "x86_64-darwin" "i686-darwin" "aarch64-darwin" "armv7a-darwin"
 
     # FreeBSD
-    "i686-freebsd" "x86_64-freebsd"
+    "i686-freebsd13" "x86_64-freebsd13"
 
     # Genode
     "aarch64-genode" "i686-genode" "x86_64-genode"
diff --git a/lib/systems/examples.nix b/lib/systems/examples.nix
index 61a67072a85..de5adad3ca5 100644
--- a/lib/systems/examples.nix
+++ b/lib/systems/examples.nix
@@ -303,6 +303,11 @@ rec {
 
   # BSDs
 
+  x86_64-freebsd = {
+    config = "x86_64-unknown-freebsd13";
+    useLLVM = true;
+  };
+
   x86_64-netbsd = {
     config = "x86_64-unknown-netbsd";
   };
diff --git a/lib/systems/inspect.nix b/lib/systems/inspect.nix
index ee213438e04..4e0bb8e672e 100644
--- a/lib/systems/inspect.nix
+++ b/lib/systems/inspect.nix
@@ -59,7 +59,7 @@ rec {
     isiOS          = { kernel = kernels.ios; };
     isLinux        = { kernel = kernels.linux; };
     isSunOS        = { kernel = kernels.solaris; };
-    isFreeBSD      = { kernel = kernels.freebsd; };
+    isFreeBSD      = { kernel = { name = "freebsd"; }; };
     isNetBSD       = { kernel = kernels.netbsd; };
     isOpenBSD      = { kernel = kernels.openbsd; };
     isWindows      = { kernel = kernels.windows; };
diff --git a/lib/systems/parse.nix b/lib/systems/parse.nix
index ac450534fe1..d8ba251503a 100644
--- a/lib/systems/parse.nix
+++ b/lib/systems/parse.nix
@@ -290,7 +290,11 @@ rec {
     # the normalized name for macOS.
     macos    = { execFormat = macho;   families = { inherit darwin; }; name = "darwin"; };
     ios      = { execFormat = macho;   families = { inherit darwin; }; };
-    freebsd  = { execFormat = elf;     families = { inherit bsd; }; };
+    # A tricky thing about FreeBSD is that there is no stable ABI across
+    # versions. That means that putting in the version as part of the
+    # config string is paramount.
+    freebsd12 = { execFormat = elf;     families = { inherit bsd; }; name = "freebsd"; version = 12; };
+    freebsd13 = { execFormat = elf;     families = { inherit bsd; }; name = "freebsd"; version = 13; };
     linux    = { execFormat = elf;     families = { }; };
     netbsd   = { execFormat = elf;     families = { inherit bsd; }; };
     none     = { execFormat = unknown; families = { }; };
@@ -431,6 +435,8 @@ rec {
         then { cpu = elemAt l 0; vendor = elemAt l 1; kernel = "redox";                      }
       else if (elemAt l 2 == "mmixware")
         then { cpu = elemAt l 0; vendor = elemAt l 1; kernel = "mmixware";                   }
+      else if hasPrefix "freebsd" (elemAt l 2)
+        then { cpu = elemAt l 0; vendor = elemAt l 1;    kernel = elemAt l 2;                }
       else if hasPrefix "netbsd" (elemAt l 2)
         then { cpu = elemAt l 0; vendor = elemAt l 1;    kernel = elemAt l 2;                }
       else if (elem (elemAt l 2) ["eabi" "eabihf" "elf"])
@@ -485,10 +491,13 @@ rec {
 
   mkSystemFromString = s: mkSystemFromSkeleton (mkSkeletonFromList (lib.splitString "-" s));
 
+  kernelName = kernel:
+    kernel.name + toString (kernel.version or "");
+
   doubleFromSystem = { cpu, kernel, abi, ... }:
     /**/ if abi == abis.cygnus       then "${cpu.name}-cygwin"
     else if kernel.families ? darwin then "${cpu.name}-darwin"
-    else "${cpu.name}-${kernel.name}";
+    else "${cpu.name}-${kernelName kernel}";
 
   tripleFromSystem = { cpu, vendor, kernel, abi, ... } @ sys: assert isSystem sys; let
     optExecFormat =
@@ -496,7 +505,7 @@ rec {
                           gnuNetBSDDefaultExecFormat cpu != kernel.execFormat)
         kernel.execFormat.name;
     optAbi = lib.optionalString (abi != abis.unknown) "-${abi.name}";
-  in "${cpu.name}-${vendor.name}-${kernel.name}${optExecFormat}${optAbi}";
+  in "${cpu.name}-${vendor.name}-${kernelName kernel}${optExecFormat}${optAbi}";
 
   ################################################################################
 
diff --git a/lib/tests/systems.nix b/lib/tests/systems.nix
index 4175dc68841..27c5ff565ca 100644
--- a/lib/tests/systems.nix
+++ b/lib/tests/systems.nix
@@ -16,17 +16,17 @@ with lib.systems.doubles; lib.runTests {
   testall = mseteq all (linux ++ darwin ++ freebsd ++ openbsd ++ netbsd ++ illumos ++ wasi ++ windows ++ embedded ++ mmix ++ js ++ genode ++ redox);
 
   testarm = mseteq arm [ "armv5tel-linux" "armv6l-linux" "armv6l-netbsd" "armv6l-none" "armv7a-linux" "armv7a-netbsd" "armv7l-linux" "armv7l-netbsd" "arm-none" "armv7a-darwin" ];
-  testi686 = mseteq i686 [ "i686-linux" "i686-freebsd" "i686-genode" "i686-netbsd" "i686-openbsd" "i686-cygwin" "i686-windows" "i686-none" "i686-darwin" ];
+  testi686 = mseteq i686 [ "i686-linux" "i686-freebsd13" "i686-genode" "i686-netbsd" "i686-openbsd" "i686-cygwin" "i686-windows" "i686-none" "i686-darwin" ];
   testmips = mseteq mips [ "mips64el-linux" "mipsel-linux" "mipsel-netbsd" ];
   testmmix = mseteq mmix [ "mmix-mmixware" ];
   testriscv = mseteq riscv [ "riscv32-linux" "riscv64-linux" "riscv32-netbsd" "riscv64-netbsd" "riscv32-none" "riscv64-none" ];
   testriscv32 = mseteq riscv32 [ "riscv32-linux" "riscv32-netbsd" "riscv32-none" ];
   testriscv64 = mseteq riscv64 [ "riscv64-linux" "riscv64-netbsd" "riscv64-none" ];
-  testx86_64 = mseteq x86_64 [ "x86_64-linux" "x86_64-darwin" "x86_64-freebsd" "x86_64-genode" "x86_64-redox" "x86_64-openbsd" "x86_64-netbsd" "x86_64-cygwin" "x86_64-solaris" "x86_64-windows" "x86_64-none" ];
+  testx86_64 = mseteq x86_64 [ "x86_64-linux" "x86_64-darwin" "x86_64-freebsd13" "x86_64-genode" "x86_64-redox" "x86_64-openbsd" "x86_64-netbsd" "x86_64-cygwin" "x86_64-solaris" "x86_64-windows" "x86_64-none" ];
 
   testcygwin = mseteq cygwin [ "i686-cygwin" "x86_64-cygwin" ];
   testdarwin = mseteq darwin [ "x86_64-darwin" "i686-darwin" "aarch64-darwin" "armv7a-darwin" ];
-  testfreebsd = mseteq freebsd [ "i686-freebsd" "x86_64-freebsd" ];
+  testfreebsd = mseteq freebsd [ "i686-freebsd13" "x86_64-freebsd13" ];
   testgenode = mseteq genode [ "aarch64-genode" "i686-genode" "x86_64-genode" ];
   testredox = mseteq redox [ "x86_64-redox" ];
   testgnu = mseteq gnu (linux /* ++ kfreebsd ++ ... */);