Fil-C on Nix

Filnix wiki

mbrock/filnix

ports/build-tools.nix

Build-platform code generators whose output targets Fil-C.

GLib's gdbus-codegen and glib-genmarshal, Meson's mkenums_simple, valac, gtkdoc-scangobj and the introspection scanner's gdump.c emit C for the package being built. Under Fil-C that C must treat GType as a pointer. Like a compiler, these tools are target-dependent, so patch them in the package set whose target is Fil-C (pkgsBuildHost): splicing then selects them for Fil-C nativeBuildInputs. The native package set, whose target is not Fil-C, keeps its ordinary tools.

GLib and gobject-introspection are native twins of the Fil-C ports, at the same versions: generated code must only use APIs the target GLib has, and Meson negotiates scanner options by the build GI's version. Only the target-neutral parts of the port patches apply; the rest assume Fil-C.

The twins are tools, not libraries for the build platform. Replacing pkgsBuildHost's glib would relink every native library there against GLib 2.80.4 (Pango, GTK, Qt, glibmm, SDL's PipeWire...), rebuilding them outside the binary cache and breaking those that need a newer GLib. So the twins are built from pkgsBuildHost but only the Fil-C set's view of it, pkgsBuildHost (and so buildPackages and splicing), names them; native packages inside pkgsBuildHost keep the ordinary GLib.

λfinal prev
let
25inherit prev
lib

The ports DSL for package set pkgs, applied to one of its packages.

28dsl=
pkgs: import./default.nix inherit lib pkgs;
used by spec twins
29build=
λpkgs pkg steps
let
32spec=
dslpkgs.forpkg steps
uses dsl
in
pkg.overridespec.overrideArgs.overrideAttrsspec.attrs
used by glib gobject-introspection-unwrapped twins

Native Qt programs must not propagate their native qtbase into Fil-C builds. Only the Fil-C view below uses these program-only modules and target hooks; native packages keep their ordinary Qt scope.

39qtToolsOnly=
λm
prev.runCommand"${m.name}-programs" outputs = m.outputs or "out";
lib.concatMapStrings
λo
mkdir -p ''$${o}
if [ -d ${m.${o}}/bin ]; then ln -s ${m.${o}}/bin ''$${o}/bin; fi
m.outputs or "out"
uses lib used by qtForFilcBuilds
47unspliced=
p: p.__spliced.hostTarget or p
used by qtForFilcBuilds
48qtForFilcBuilds=
λnative filc
native
//
lib.mapAttrs_: qtToolsOnly lib.filterAttrsname: v: lib.hasPrefix"qt" name ∧ lib.isDerivationv native
//
57qmake=
prev.makeSetupHook
58name=
"qmake-hook"
59propagatedBuildInputs=
unsplicedfilc.qmake unsplicedfilc.qtbase.dev
prev.writeText"qmake-filc.sh" ""
64wrapQtAppsHook=
prev.makeSetupHook
65name=
"wrap-qt5-apps-hook"
66propagatedBuildInputs=
unsplicedfilc.qtbase.dev final.makeBinaryWrapper unsplicedfilc.qtwayland.dev
prev.path + "/pkgs/development/libraries/qt-5/hooks/wrap-qt-apps-hook.sh"
uses lib qtToolsOnly unspliced
74twins=
λbh
let
77inherit dslbh
arg use pin patch skipPatch

Select hunks of a port patch by file, keeping one source for them.

86hunks=
λname portPatch files
bh.runCommandname nativeBuildInputs = bh.patchutils;
filterdiff ${lib.concatMapStringsSep" " f: "-i '*/${f}'" files} \
${portPatch} > $out
test -s $out
uses lib used by glib gobject-introspection-unwrapped
94glib=
buildbh bh.glib
pin"2.80.4" "sha256-JOApxd/JtE5Fc2l63zMHipgnxIk4VVAEs7kJb6TqA08="
patchhunks"glib-filc-generators.patch" ../ports/patch/glib-2.80.4.patch "gio/gdbus-2.0/codegen/codegen.py" "gobject/glib-genmarshal.in"
skipPatch"split-dev-programs.patch"
patch../patches/glib-split-backport.patch
arg
105libsysprof-capture=
null

The Fil-C GI port supplies the target GLib GIRs.

107withIntrospection=
false
use
110doCheck=
false
111mesonFlags=
"-Ddevbindir=${placeholder"dev"}/bin" "-Dglib_debug=disabled" "-Ddocumentation=true" lib.mesonBool"dtrace" false lib.mesonBool"systemtap" false "-Dnls=enabled" lib.mesonEnable"introspection" false "-Dtests=false"
use
λold

Native build tools such as gdk-pixbuf propagate the ordinary GLib, whose newer, unpatched generators can precede these on PATH and in the build pkg-config path, where Meson looks them up (gio-2.0's gdbus_codegen). Put these first once all hooks have run.

128postFixup=
old.postFixup or ""
+
mkdir -p $dev/libexec/filc-generators
for tool in gdbus-codegen glib-genmarshal glib-mkenums; do
ln -s $dev/bin/$tool $dev/libexec/filc-generators/$tool
done
cat >> $dev/nix-support/setup-hook <<EOF
_filcGlibGenerators() {
PATH="$dev/libexec/filc-generators:\$PATH"
export PKG_CONFIG_PATH_FOR_BUILD="$dev/lib/pkgconfig\''${PKG_CONFIG_PATH_FOR_BUILD:+:\$PKG_CONFIG_PATH_FOR_BUILD}"
}
postHooks+=(_filcGlibGenerators)
EOF
uses arg build hunks lib patch pin skipPatch use
145gobject-introspection-unwrapped=
buildbh bh.gobject-introspection-unwrapped
arg
149inherit
glib

Only its library path reaches the scanner; keep it the one the twin has always had.

152cairo=
bh.cairo.overrideinherit glib;
pin"1.80.1" "sha256-od98Qk4VvaGrY5wA6QUbmt9c6hqeUS+KYDtTzRmbxtg="
patchhunks"gobject-introspection-filc-scanner.patch" ../ports/patch/gobject-introspection-1.80.1.patch "girepository/gdump.c" "giscanner/ccompiler.py"
patch../patches/gobject-introspection-filc-tools.patch
patch../patches/gobject-introspection-link-environment.patch
use
λold
166postPatch=
old.postPatch or ""
+
# Fil-C GLib's gtype.h provides uintptr_t; native GLib's does not.
sed -i '/#include <stdio.h>/a #include <stdint.h>' girepository/gdump.c
# Fil-C builds have no ldd on PATH; the scanner runs it on dumpers.
substituteInPlace giscanner/shlibs.py \
--replace-fail "['ldd', binary.args[0]]" "['${lib.getBinbh.stdenv.cc.libc}/bin/ldd', binary.args[0]]"

Resolve GIR includes against the Fil-C libraries being linked rather than build-platform GIRs, which XDG_DATA_DIRS lists first. The scanner searches GI_GIR_PATH before XDG_DATA_DIRS.

176postFixup=
old.postFixup or ""
+
cat >> "$dev/nix-support/setup-hook" <<'EOF'
_filcTargetGirPath() {
if [ -d "$1/share/gir-1.0" ]; then
addToSearchPath GI_GIR_PATH "$1/share/gir-1.0"
fi
}
addEnvHooks "$targetOffset" _filcTargetGirPath
EOF
# Native PyGObject propagates the ordinary GI, whose scanner
# can precede this one on PATH; see the GLib twin.
cat >> "$dev/nix-support/setup-hook" <<EOF
_filcGirTools() {
PATH="$dev/bin:\$PATH"
export PKG_CONFIG_PATH_FOR_BUILD="$dev/lib/pkgconfig\''${PKG_CONFIG_PATH_FOR_BUILD:+:\$PKG_CONFIG_PATH_FOR_BUILD}"
}
postHooks+=(_filcGirTools)
EOF
uses arg build hunks lib patch pin use
in
200inherit
glib gobject-introspection-unwrapped

The Fil-C-targeted wrapper, which the set itself no longer names.

202gobject-introspection=
bh.callPackagebh.path + "/pkgs/development/libraries/gobject-introspection/wrapper.nix" inherit gobject-introspection-unwrapped;

Like the GLib twins, these generators are patched only in the Fil-C-facing view, not in native libraries' own build dependencies.

210vala=
buildbh bh.vala
patch../patches/vala-pointer-once.patch
use
λold
213postPatch=
old.postPatch or ""
+
# Keep the shipped patched C from being regenerated by old valac.
touch codegen/codegen.vala.stamp
217postFixup=
old.postFixup or ""
+
cat >> "$out/nix-support/setup-hook" <<'EOF'
_filcValaRegenerate() {
find . \( -name '*_vala.stamp' -o -name '*.vala.stamp' \) -delete
}
preConfigureHooks+=(_filcValaRegenerate)
EOF
uses build dsl
in
prev.stdenv.targetPlatform.isFilc ∧ ¬prev.stdenv.hostPlatform.isFilc
→
let
232inherit dslprev
patch use
in

Meson is not linked by native libraries, so it is patched for the whole set; meson-python there propagates it to Fil-C Python builds.

Qt's qmake hook is spliced from this set's buildPackages. Here Qt still differs from the native one without the GLib twin (qttools and so qttranslations reference another qtbase), and a native Qt module here (reached through wrapQtAppsHook, e.g. qtsvg) saw two qtbases: its setup hook failed with "detected mismatched Qt dependencies". Qt emits no GType code, so use the ordinary native Qt, which also comes from cache.nixos.org.

248qt5=
final.buildPackages.qt5
249libsForQt5=
final.buildPackages.libsForQt5
250qt6=
final.buildPackages.qt6
251qt6Packages=
final.buildPackages.qt6Packages

Likewise the gobject-introspection wrapper: with a Fil-C target it wraps the scanner for cross use and propagates the Fil-C GI, so native libraries here that link GI (PyGObject, and through it graphene, GTK 4, GStreamer, PipeWire, SDL) left the cache. Fil-C packages get the twin's wrapper from twins below.

257gobject-introspection=
final.buildPackages.gobject-introspection

PyGObject adds Python's pkg-config path when host != target, meaning when cross-compiled (NixOS/nixpkgs#378447); here that holds natively.

260pythonPackagesExtensions=
prev.pythonPackagesExtensions ++ _: pyprev: pygobject3 = pyprev.pygobject3.overrideAttrspreConfigure = "";;
prev.stdenv.hostPlatform.isFilc ∧ ¬prev.stdenv.buildPlatform.isFilc
→

The default targetPackages.stdenv.cc bootstraps an ordinary LLVM cross compiler for gnufilc0. Runtime wrappers are Fil-C programs too: compile them with this set's existing Fil-C compiler, not a new cross toolchain.

273makeBinaryWrapper=
prev.makeBinaryWrapper.overridecc = prev.stdenv.cc;
274pkgsBuildHost=
prev.pkgsBuildHost
//
twinsprev.pkgsBuildHost
//
278qt5=
qtForFilcBuildsprev.pkgsBuildHost.qt5 final.qt5
279libsForQt5=
qtForFilcBuildsprev.pkgsBuildHost.libsForQt5 final.libsForQt5
else
{ }