nixpkgs/pkgs/os-specific/windows/default.nix
Adam Joseph 2affd455a4 gccCrossStageStatic: enable dynamic libraries, rename to gccWithoutTargetLibc
This commit allows `gccCrossStageStatic` to build dynamically-linked
libraries.  Since is no longer restricted to building static
libraries its name is no longer appropriate, and this commit also
renames it to the more-accurate `gccWithoutTargetLibc`.

By default, you can't build a gcc that knows how to create dynamic
libraries unless you have already built the targetPlatform libc.

Because of this, our gcc cross-compiler is built in two stages:

  1. Build a cross-compiler (gccCrossStageStatic) that can build
     only static libraries.

  2. Use gccCrossStageStatic to compile the targetPlatform libc.

  3. Use the targetPlatform libc to build a fully-capable cross
     compiler.

You might notice that this pattern looks very similar to what we do
with `xgcc` in the stdenv bootstrap.  Indeed it is!  I would like to
work towards getting the existing stdenv bootstrap to handle cross
compilers as well.  However we don't want to cripple `stdenv.xgcc`
by taking away its ability to build dynamic libraries.

It turns out that the only thing gcc needs the targetPlatform libc
for is to emit a DT_NEEDED for `-lc` into `libgcc.so`.  That's it!
And since we don't use `gccCrossStageStatic` to build anything other
than libc, it's safe to omit the `DT_NEEDED` because that `libgcc`
will never be loaded by anything other than `libc`.  So `libc` will
already be in the process's address space.

Other people have noticed this; crosstool-ng has been using this
approach for a very long time:

  36ad0b17a7/scripts/build/cc/gcc.sh (L638-L640)
2023-07-01 13:12:40 -07:00

51 lines
1.2 KiB
Nix

{ lib, stdenv, buildPackages
, newScope, overrideCC, crossLibcStdenv, libcCross
}:
lib.makeScope newScope (self: with self; {
cygwinSetup = callPackage ./cygwin-setup { };
jom = callPackage ./jom { };
w32api = callPackage ./w32api { };
mingwrt = callPackage ./mingwrt { };
mingw_runtime = mingwrt;
mingw_w64 = callPackage ./mingw-w64 {
stdenv = crossLibcStdenv;
};
crossThreadsStdenv = overrideCC crossLibcStdenv
(if stdenv.hostPlatform.useLLVM or false
then buildPackages.llvmPackages_8.clangNoLibcxx
else buildPackages.gccWithoutTargetLibc.override (old: {
bintools = old.bintools.override {
libc = libcCross;
};
libc = libcCross;
}));
mingw_w64_headers = callPackage ./mingw-w64/headers.nix { };
mingw_w64_pthreads = callPackage ./mingw-w64/pthreads.nix {
stdenv = crossThreadsStdenv;
};
mcfgthreads_pre_gcc_13 = callPackage ./mcfgthreads/pre_gcc_13.nix {
stdenv = crossThreadsStdenv;
};
mcfgthreads = callPackage ./mcfgthreads {
stdenv = crossThreadsStdenv;
};
npiperelay = callPackage ./npiperelay { };
pthreads = callPackage ./pthread-w32 { };
wxMSW = callPackage ./wxMSW-2.8 { };
libgnurx = callPackage ./libgnurx { };
})