Cross compilation fixes [april 2020] #84415

matthewbauer · 2020-04-06T01:50:57Z

More cross-compilation fixes.

Motivation for this change

Things done

- Need custom pkg-config setting - add wayland & libxkbcommon

doronbehar · 2020-04-06T07:50:10Z

@matthewbauer I just came about #83575 which suggests that dvtm should have ncurses in it's native build inputs (or alike). Is there a chance you could take a look at that and perhaps fix it in this PR as well? Thanks.

Mic92 · 2020-04-06T15:09:56Z

pkgs/development/libraries/libvpx/default.nix

    # libvpx darwin targets include darwin version (ie. ARCH-darwinXX-gcc, XX being the darwin version)
    # See all_platforms: https://github.com/webmproject/libvpx/blob/master/configure
    # Darwin versions: 10.4=8, 10.5=9, 10.6=10, 10.7=11, 10.8=12, 10.9=13, 10.10=14
-    "--force-target=${stdenv.hostPlatform.config}${
+    "--force-target=${stdenv.hostPlatform.parsed.cpu.name}-${stdenv.hostPlatform.parsed.kernel.name}${


Nice. I strugged with this one. I think so on aarch64 it is still incorrect because arm64 != aarch64.

I was able to build for aarch64. I think they rewrite it here:

https://github.com/webmproject/libvpx/blob/0c46742f56d06bf284c781bd754eff3b1d97c3c8/build/make/configure.sh#L723

Mic92 · 2020-04-06T15:16:44Z

pkgs/applications/version-management/git-and-tools/git/default.nix

@@ -88,7 +90,7 @@ stdenv.mkDerivation {

  makeFlags = [
    "prefix=\${out}"
-    "SHELL_PATH=${stdenv.shell}"
+    "SHELL_PATH=${if (stdenv.hostPlatform != stdenv.buildPlatform) then "/bin/sh" else stdenv.shell}"


Suggested change

"SHELL_PATH=${if (stdenv.hostPlatform != stdenv.buildPlatform) then "/bin/sh" else stdenv.shell}"

"SHELL_PATH=${runtimeShell}"

Just read the commit message... The only pure alternative to your approach would be to replace stdenv.shell with runtimeShell in $out.

Otherwise if we have a sandbox build /bin/sh is reasonable reproducible, could add the reasoning as a comment above for a future reader?

We are referencing "/bin/sh" in nixpkgs … oh no.

Yeah if it is about the old vs new version of the code (stateful) I like to put in the commit message, but if it is about the new version of the code alone, I rather it be a comment.

Comments have a prayer of being edited to stay up to date :), but commit messages only describe a moment in time.

Yeah - patch-shebangs.sh bails out when the path is in the nix store.

I'll leave this change out of this set for now. Using /bin/sh is definitely not good, so some other fix is needed. Git will still build, you just can't run some of its shell scripts.

🤔 isn't this a general problem with cross builds, for e.g. Python install scripts?

How about using a substitution set for buildDeps that should be replaced with runDeps? And maybe automatically testing for buildDeps that are referenced in the output but not specifically allowed?

nixos/modules/config/fonts/fontconfig.nix

Ericson2314 · 2020-04-06T15:44:47Z

pkgs/development/libraries/librsvg/default.nix

+    [target."${toRustTarget stdenv.hostPlatform}"]
+    "linker" = "${stdenv.cc}/bin/${stdenv.cc.targetPrefix}cc"
+    EOF
+  '';


Can we share this with the other places we do this?

Some setup hook would be nice if it is not possible to hard code this during compilation.

Yeah a better solution would be nice.

I'm actually going to leave this out of this batch of cross fixes since there are a lot of questions on this (like why can't we do vala / gtk-doc / gobject-introspection when cross-compiling). These commits still exist on my other branch though:

https://github.com/matthewbauer/nixpkgs/tree/kiosk3

- add glib to nativeBuildInputs - only update loaders cache on native builds

This is needed in cross where systemd is not in path.

Also set wayland-scanner to proper path

These should be runtime, not build time deps

Unfortunately, we need to emulate the system to get a real cache. Native version doesn’t know the right paths.

We can’t cross-compile the cache, so just skip it for now.

This prevents duplication in cross-compiled nixos machines. The bootstrapped glibc differs from the natively compiled one, so we get two glibc’s in the closure. To reduce closure size, just use stdenv.cc.libc where available.

fixes cross compilation

This fixes an evaluation error that occurs when we don’t have bluez.test. getOutput defaults to "out" in these cases.

In NixOS#84415, autoPatchelfHook was taught to use the correct path to the readelf binary when a crossSystem is specified. Unfortunately, the remainder of the functionality in the script depended on ldd, which only reads ELF files of its own architecture. It has the further unfortunate quality of not reporting any useful error, but rather that the file is not a dynamic executable. This change uses patchelf to directly analyze the DT_NEEDED tags in the target files instead, which correctly works across architectures. It also updates the use of objdump to be prefix-aware $OBJDUMP (which would have been required in the PR mentioned above, but we never made it that far into the script execution).

In NixOS#84415, autoPatchelfHook was taught to use the correct path to the readelf binary when a crossSystem is specified. Unfortunately, the remainder of the functionality in the script depended on ldd, which only reads ELF files of its own architecture. It has the further unfortunate quality of not reporting any useful error, but rather that the file is not a dynamic executable. This change uses patchelf to directly analyze the DT_NEEDED tags in the target files instead, which correctly works across architectures. It also updates the use of objdump to be prefix-aware $OBJDUMP (which would have been required in the PR mentioned above, but we never made it that far into the script execution). (cherry picked from commit b79483d)

In #84415, autoPatchelfHook was taught to use the correct path to the readelf binary when a crossSystem is specified. Unfortunately, the remainder of the functionality in the script depended on ldd, which only reads ELF files of its own architecture. It has the further unfortunate quality of not reporting any useful error, but rather that the file is not a dynamic executable. This change uses patchelf to directly analyze the DT_NEEDED tags in the target files instead, which correctly works across architectures. It also updates the use of objdump to be prefix-aware $OBJDUMP (which would have been required in the PR mentioned above, but we never made it that far into the script execution). (cherry picked from commit b79483d)

In NixOS#84415, autoPatchelfHook was taught to use the correct path to the readelf binary when a crossSystem is specified. Unfortunately, the remainder of the functionality in the script depended on ldd, which only reads ELF files of its own architecture. It has the further unfortunate quality of not reporting any useful error, but rather that the file is not a dynamic executable. This change uses patchelf to directly analyze the DT_NEEDED tags in the target files instead, which correctly works across architectures. It also updates the use of objdump to be prefix-aware $OBJDUMP (which would have been required in the PR mentioned above, but we never made it that far into the script execution). (cherry picked from commit b79483d)

retroarch: add wayland dependency and fix cross

7d278d7

- Need custom pkg-config setting - add wayland & libxkbcommon

matthewbauer requested a review from Ericson2314 April 6, 2020 01:50

ofborg bot added 6.topic: GNOME GNOME desktop environment and its underlying platform 6.topic: nixos 8.has: module (update) labels Apr 6, 2020

matthewbauer requested review from FRidh and jonringer as code owners April 6, 2020 15:06

ofborg bot added the 6.topic: python label Apr 6, 2020

Mic92 reviewed Apr 6, 2020

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ofborg bot added 10.rebuild-darwin: 501+ 10.rebuild-darwin: 2501-5000 10.rebuild-linux: 501+ 10.rebuild-linux: 5001+ labels Apr 6, 2020

Mic92 reviewed Apr 6, 2020

View reviewed changes

nixos/modules/config/fonts/fontconfig.nix Show resolved Hide resolved

Ericson2314 reviewed Apr 6, 2020

View reviewed changes

matthewbauer added 13 commits April 6, 2020 16:36

git: fix cross compilation

d0dbdfe

cracklib: only use local binaries on native build

0f41c15

vulkan-loader: make cmake a native build input

f834747

gdk-pixbuf: support cross compilation

139fd8b

- add glib to nativeBuildInputs - only update loaders cache on native builds

plymouth: set systemd-tty-ask-password-agent path

3a71e62

This is needed in cross where systemd is not in path.

libva: add wayland as native build input

65b967f

Also set wayland-scanner to proper path

xorg.libXScrnSaver: add utilmacros and malloc 0

777a2b4

epiphany: include gtk3 build dependency

80be56b

glib: put gsettings directory in target

36109cd

These should be runtime, not build time deps

hicolor-icon-theme: only add target icons to deps

93a8887

gdk-pixbuf: make target env hook

6c5983a

Unfortunately, we need to emulate the system to get a real cache. Native version doesn’t know the right paths.

fontconfig: only generate cache on native compilation

8a5059e

We can’t cross-compile the cache, so just skip it for now.

matthewbauer added 2 commits April 6, 2020 16:36

dvtm: add ncurses dev input to PATH

51ab062

fixes cross compilation

python-dbusmock: avoid eval error when missing test output of bluez

c6ff360

This fixes an evaluation error that occurs when we don’t have bluez.test. getOutput defaults to "out" in these cases.

matthewbauer force-pushed the mb-cross-fixes-april2020 branch from 9cdfaf8 to c6ff360 Compare April 6, 2020 20:37

matthewbauer changed the base branch from master to staging April 6, 2020 20:38

ofborg bot added 6.topic: haskell 6.topic: policy discussion 8.has: changelog 8.has: documentation 8.has: clean-up 8.has: package (new) and removed 6.topic: haskell 6.topic: policy discussion 8.has: changelog 8.has: documentation labels Apr 6, 2020

matthewbauer changed the base branch from staging to master April 13, 2020 20:47

matthewbauer changed the base branch from master to staging April 13, 2020 20:47

matthewbauer merged commit e520d6a into NixOS:staging Apr 13, 2020

doronbehar mentioned this pull request Apr 26, 2020

dvtm doesn't build for aarch64 #83575

Closed

flokli mentioned this pull request May 23, 2020

makeFontsCache: Fix cross-compilation, use nativeBuildInputs #73344

Merged

10 tasks

petersjt014 mentioned this pull request Jun 6, 2020

Update nixpkgs submodule illegalprime/nixos-on-arm#27

Open

matthewbauer mentioned this pull request Dec 29, 2020

Cross-compiled git uses wrong bash #107639

Closed

impl mentioned this pull request Sep 11, 2021

autoPatchelfHook: fix detection under crossSystem #137351

Merged

12 tasks

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Cross compilation fixes [april 2020] #84415

Cross compilation fixes [april 2020] #84415

matthewbauer commented Apr 6, 2020

doronbehar commented Apr 6, 2020

Mic92 Apr 6, 2020

matthewbauer Apr 6, 2020

Mic92 Apr 6, 2020

Mic92 Apr 6, 2020

Mic92 Apr 6, 2020

Profpatsch Apr 6, 2020

Ericson2314 Apr 6, 2020

matthewbauer Apr 6, 2020

wmertens Dec 29, 2020

Ericson2314 Apr 6, 2020

Mic92 Apr 6, 2020

matthewbauer Apr 6, 2020

matthewbauer Apr 6, 2020

	"SHELL_PATH=${if (stdenv.hostPlatform != stdenv.buildPlatform) then "/bin/sh" else stdenv.shell}"
	"SHELL_PATH=${runtimeShell}"

Cross compilation fixes [april 2020] #84415

Cross compilation fixes [april 2020] #84415

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matthewbauer commented Apr 6, 2020

Motivation for this change

Things done

doronbehar commented Apr 6, 2020

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