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lib: Consolidate platform configurations (used for crossSystem)

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This is good for maintenance and education.
This commit is contained in:
John Ericson 2017-05-23 18:04:15 -04:00
parent b20f20d3eb
commit 20e756a093
6 changed files with 200 additions and 173 deletions
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52
doc/cross-compilation.xml
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@ -85,7 +85,8 @@
This field is obsolete and will soon disappear—please do not use it.
</para></note>
<para>
The exact scheme these fields is a bit ill-defined due to a long and convoluted evolution, but this is slowly being cleaned up.
The exact schema these fields follow is a bit ill-defined due to a long and convoluted evolution, but this is slowly being cleaned up.
You can see examples of ones used in practice in <literal>lib.systems.examples</literal>; note how they are not all very consistent.
For now, here are few fields can count on them containing:
</para>
<variablelist>
@ -118,8 +119,27 @@
This is a nix representation of a parsed LLVM target triple with white-listed components.
This can be specified directly, or actually parsed from the <varname>config</varname>.
[Technically, only one need be specified and the others can be inferred, though the precision of inference may not be very good.]
See <literal>lib.systems.parse</literal> for the exact representation, along with some <literal>is*</literal>predicates.
These predicates are superior to the ones in <varname>stdenv</varname> as they aren't tied to the build platform (host, as previously discussed, would be a saner default).
See <literal>lib.systems.parse</literal> for the exact representation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>libc</varname></term>
<listitem>
<para>
This is a string identifying the standard C library used.
Valid identifiers include "glibc" for GNU libc, "libsystem" for Darwin's Libsystem, and "uclibc" for µClibc.
It should probably be refactored to use the module system, like <varname>parse</varname>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>is*</varname></term>
<listitem>
<para>
These predicates are defined in <literal>lib.systems.inspect</literal>, and slapped on every platform.
They are superior to the ones in <varname>stdenv</varname> as they force the user to be explicit about which platform they are inspecting.
Please use these instead of those.
</para>
</listitem>
</varlistentry>
@ -128,7 +148,7 @@
<listitem>
<para>
This is, quite frankly, a dumping ground of ad-hoc settings (it's an attribute set).
See <literal>lib.systems.platforms</literal> for examples—there's hopefully one in there that will work verbatim for each platform one is working.
See <literal>lib.systems.platforms</literal> for examples—there's hopefully one in there that will work verbatim for each platform that is working.
Please help us triage these flags and give them better homes!
</para>
</listitem>
@ -184,11 +204,27 @@
More information needs to moved from the old wiki, especially <link xlink:href="https://nixos.org/wiki/CrossCompiling" />, for this section.
</para></note>
<para>
Many sources (manual, wiki, etc) probably mention passing <varname>system</varname>, <varname>platform</varname>, and, optionally, <varname>crossSystem</varname> to nixpkgs:
<literal>import &lt;nixpkgs&gt; { system = ..; platform = ..; crossSystem = ..; }</literal>.
<varname>system</varname> and <varname>platform</varname> together determine the system on which packages are built, and <varname>crossSystem</varname> specifies the platform on which packages are ultimately intended to run, if it is different.
This still works, but with more recent changes, one can alternatively pass <varname>localSystem</varname>, containing <varname>system</varname> and <varname>platform</varname>, for symmetry.
Nixpkgs can be instantiated with <varname>localSystem</varname> alone, in which case there is no cross compiling and everything is built by and for that system,
or also with <varname>crossSystem</varname>, in which case packages run on the latter, but all building happens on the former.
Both parameters take the same schema as the 3 (build, host, and target) platforms defined in the previous section.
As mentioned above, <literal>lib.systems.examples</literal> has some platforms which are used as arguments for these parameters in practice.
You can use them programmatically, or on the command line like <command>nix-build &lt;nixpkgs&gt; --arg crossSystem '(import &lt;nixpkgs/lib&gt;).systems.examples.fooBarBaz'</command>.
</para>
<para>
While one is free to pass both parameters in full, there's a lot of logic to fill in missing fields.
As discussed in the previous section, only one of <varname>system</varname>, <varname>config</varname>, and <varname>parsed</varname> is needed to infer the other two.
Additionally, <varname>libc</varname> will be inferred from <varname>parse</varname>.
Finally, <literal>localSystem.system</literal> is also <emphasis>impurely</emphasis> inferred based on the platform evaluation occurs.
This means it is often not necessary to pass <varname>localSystem</varname> at all, as in the command-line example in the previous paragraph.
</para>
<note>
<para>
Many sources (manual, wiki, etc) probably mention passing <varname>system</varname>, <varname>platform</varname>, along with the optional <varname>crossSystem</varname> to nixpkgs:
<literal>import &lt;nixpkgs&gt; { system = ..; platform = ..; crossSystem = ..; }</literal>.
Passing those two instead of <varname>localSystem</varname> is still supported for compatibility, but is discouraged.
Indeed, much of the inference we do for these parameters is motivated by compatibility as much as convenience.
</para>
</note>
<para>
One would think that <varname>localSystem</varname> and <varname>crossSystem</varname> overlap horribly with the three <varname>*Platforms</varname> (<varname>buildPlatform</varname>, <varname>hostPlatform,</varname> and <varname>targetPlatform</varname>; see <varname>stage.nix</varname> or the manual).
Actually, those identifiers are purposefully not used here to draw a subtle but important distinction:

1
lib/systems/default.nix
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@ -5,6 +5,7 @@ rec {
parse = import ./parse.nix;
inspect = import ./inspect.nix;
platforms = import ./platforms.nix;
examples = import ./examples.nix;
# Elaborate a `localSystem` or `crossSystem` so that it contains everything
# necessary.

130
lib/systems/examples.nix Normal file
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@ -0,0 +1,130 @@
# These can be passed to nixpkgs as either the `localSystem` or
# `crossSystem`. They are put here for user convenience, but also used by cross
# tests and linux cross stdenv building, so handle with care!
let platforms = import ./platforms.nix; in
rec {
#
# Linux
#
sheevaplug = rec {
config = "armv5te-unknown-linux-gnueabi";
bigEndian = false;
arch = "armv5te";
float = "soft";
withTLS = true;
libc = "glibc";
platform = platforms.sheevaplug;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
raspberryPi = rec {
config = "armv6l-unknown-linux-gnueabihf";
bigEndian = false;
arch = "armv6l";
float = "hard";
fpu = "vfp";
withTLS = true;
libc = "glibc";
platform = platforms.raspberrypi;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
armv7l-hf-multiplatform = rec {
config = "arm-unknown-linux-gnueabihf";
bigEndian = false;
arch = "armv7-a";
float = "hard";
fpu = "vfpv3-d16";
withTLS = true;
libc = "glibc";
platform = platforms.armv7l-hf-multiplatform;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
aarch64-multiplatform = rec {
config = "aarch64-unknown-linux-gnu";
bigEndian = false;
arch = "aarch64";
withTLS = true;
libc = "glibc";
platform = platforms.aarch64-multiplatform;
inherit (platform) gcc;
};
scaleway-c1 = armv7l-hf-multiplatform // rec {
platform = platforms.scaleway-c1;
inherit (platform) gcc;
inherit (gcc) fpu;
};
pogoplug4 = rec {
arch = "armv5tel";
config = "armv5tel-softfloat-linux-gnueabi";
float = "soft";
platform = platforms.pogoplug4;
inherit (platform) gcc;
libc = "glibc";
withTLS = true;
openssl.system = "linux-generic32";
};
fuloongminipc = rec {
config = "mips64el-unknown-linux-gnu";
bigEndian = false;
arch = "mips";
float = "hard";
withTLS = true;
libc = "glibc";
platform = platforms.fuloong2f_n32;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
#
# Darwin
#
iphone64 = {
config = "aarch64-apple-darwin14";
arch = "arm64";
libc = "libsystem";
platform = {};
};
iphone32 = {
config = "arm-apple-darwin10";
arch = "armv7-a";
libc = "libsystem";
platform = {};
};
#
# Windows
#
# 32 bit mingw-w64
mingw32 = {
config = "i686-pc-mingw32";
arch = "x86"; # Irrelevant
libc = "msvcrt"; # This distinguishes the mingw (non posix) toolchain
platform = {};
};
# 64 bit mingw-w64
mingwW64 = {
# That's the triplet they use in the mingw-w64 docs.
config = "x86_64-pc-mingw32";
arch = "x86_64"; # Irrelevant
libc = "msvcrt"; # This distinguishes the mingw (non posix) toolchain
platform = {};
};
}

9
lib/systems/platforms.nix
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@ -255,6 +255,10 @@ rec {
arch = "armv6";
fpu = "vfp";
float = "hard";
# TODO(@Ericson2314) what is this and is it a good idea? It was
# used in some cross compilation examples but not others.
#
# abi = "aapcs-linux";
};
};
@ -460,7 +464,10 @@ rec {
'';
kernelTarget = "vmlinux";
uboot = null;
gcc.arch = "loongson2f";
gcc = {
arch = "loongson2f";
abi = "n32";
};
};
beaglebone = armv7l-hf-multiplatform // {

92
pkgs/stdenv/linux/make-bootstrap-tools-cross.nix
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@ -6,91 +6,19 @@ let
lib = import ../../../lib;
pkgsFun = import ../../..;
sheevaplugCrossSystem = {
crossSystem = rec {
config = "arm-linux-gnueabi";
bigEndian = false;
arch = "armv5te";
float = "soft";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.sheevaplug;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
};
raspberrypiCrossSystem = {
crossSystem = rec {
config = "arm-linux-gnueabihf";
bigEndian = false;
arch = "armv6";
float = "hard";
fpu = "vfp";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.raspberrypi;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
};
armv7l-hf-multiplatform-crossSystem = {
crossSystem = rec {
config = "arm-linux-gnueabihf";
bigEndian = false;
arch = "armv7-a";
float = "hard";
fpu = "vfpv3-d16";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.armv7l-hf-multiplatform;
openssl.system = "linux-generic32";
inherit (platform) gcc;
};
};
aarch64-multiplatform-crossSystem = {
crossSystem = rec {
config = "aarch64-linux-gnu";
bigEndian = false;
arch = "aarch64";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.aarch64-multiplatform;
inherit (platform) gcc;
};
};
scaleway-c1-crossSystem.crossSystem = armv7l-hf-multiplatform-crossSystem.crossSystem // rec {
platform = lib.systems.platforms.scaleway-c1;
inherit (platform) gcc;
inherit (gcc) fpu;
};
pogoplug4-crossSystem.crossSystem = {
arch = "armv5tel";
config = "armv5tel-softfloat-linux-gnueabi";
float = "soft";
platform = lib.systems.platforms.pogoplug4;
inherit (lib.systems.platforms.pogoplug4) gcc;
libc = "glibc";
withTLS = true;
openssl.system = "linux-generic32";
};
inherit (lib.systems.examples)
sheevaplug raspberryPi armv7l-hf-multiplatform
aarch64-multiplatform scaleway-c1 pogoplug4;
selectedCrossSystem =
if toolsArch == "armv5tel" then sheevaplugCrossSystem else
if toolsArch == "scaleway" then scaleway-c1-crossSystem else
if toolsArch == "pogoplug4" then pogoplug4-crossSystem else
if toolsArch == "armv6l" then raspberrypiCrossSystem else
if toolsArch == "armv7l" then armv7l-hf-multiplatform-crossSystem else
if toolsArch == "aarch64" then aarch64-multiplatform-crossSystem else null;
if toolsArch == "armv5tel" then sheevaplug else
if toolsArch == "scaleway" then scaleway-c1 else
if toolsArch == "pogoplug4" then pogoplug4 else
if toolsArch == "armv6l" then raspberryPi else
if toolsArch == "armv7l" then armv7l-hf-multiplatform else
if toolsArch == "aarch64" then aarch64-multiplatform else null;
pkgs = pkgsFun ({inherit system;} // selectedCrossSystem);
pkgs = pkgsFun ({ inherit system; crossSystem = selectedCrossSystem; });
glibc = pkgs.libcCross;
bash = pkgs.bash;

89
pkgs/top-level/release-cross.nix
View File

@ -89,101 +89,26 @@ in
guile = nativePlatforms;
};
darwinToAarch64 = let
crossSystem = {
config = "aarch64-apple-darwin14";
arch = "arm64";
libc = "libSystem";
};
in mapTestOnCross crossSystem darwinCommon;
crossIphone64 = mapTestOnCross lib.systems.examples.iphone64 darwinCommon;
darwinToArm = let
crossSystem = {
config = "arm-apple-darwin10";
arch = "armv7-a";
libc = "libSystem";
};
in mapTestOnCross crossSystem darwinCommon;
crossIphone32 = mapTestOnCross lib.systems.examples.iphone32 darwinCommon;
/* Test some cross builds to the Sheevaplug */
crossSheevaplugLinux = let
crossSystem = {
config = "armv5tel-unknown-linux-gnueabi";
bigEndian = false;
arch = "arm";
float = "soft";
withTLS = true;
platform = lib.systems.platforms.sheevaplug;
libc = "glibc";
openssl.system = "linux-generic32";
};
in mapTestOnCross crossSystem (linuxCommon // {
crossSheevaplugLinux = mapTestOnCross lib.systems.examples.sheevaplug (linuxCommon // {
ubootSheevaplug = nativePlatforms;
});
/* Test some cross builds on 32 bit mingw-w64 */
crossMingw32 = let
crossSystem = {
config = "i686-pc-mingw32";
arch = "x86"; # Irrelevant
libc = "msvcrt"; # This distinguishes the mingw (non posix) toolchain
platform = {};
};
in mapTestOnCross crossSystem windowsCommon;
crossMingw32 = mapTestOnCross lib.systems.examples.mingw32 windowsCommon;
/* Test some cross builds on 64 bit mingw-w64 */
crossMingwW64 = let
crossSystem = {
# That's the triplet they use in the mingw-w64 docs.
config = "x86_64-pc-mingw32";
arch = "x86_64"; # Irrelevant
libc = "msvcrt"; # This distinguishes the mingw (non posix) toolchain
platform = {};
};
in mapTestOnCross crossSystem windowsCommon;
crossMingwW64 = mapTestOnCross lib.systems.examples.mingwW64 windowsCommon;
/* Linux on the fuloong */
fuloongminipc = let
crossSystem = {
config = "mips64el-unknown-linux-gnu";
bigEndian = false;
arch = "mips";
float = "hard";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.fuloong2f_n32;
openssl.system = "linux-generic32";
gcc = {
arch = "loongson2f";
abi = "n32";
};
};
in mapTestOnCross crossSystem linuxCommon;
fuloongminipc = mapTestOnCross lib.systems.examples.fuloongminipc linuxCommon;
/* Linux on Raspberrypi */
rpi = let
crossSystem = {
config = "armv6l-unknown-linux-gnueabi";
bigEndian = false;
arch = "arm";
float = "hard";
fpu = "vfp";
withTLS = true;
libc = "glibc";
platform = lib.systems.platforms.raspberrypi;
openssl.system = "linux-generic32";
gcc = {
arch = "armv6";
fpu = "vfp";
float = "softfp";
abi = "aapcs-linux";
};
};
in mapTestOnCross crossSystem (linuxCommon // {
rpi = mapTestOnCross lib.systems.examples.raspberryPi (linuxCommon // {
vim = nativePlatforms;
unzip = nativePlatforms;
ddrescue = nativePlatforms;