rust-bindgen/rustPlatform.bindgenHook: Missing target triplet (& ABI) fixes from CC wrapper

[OPNA2608]

Nixpkgs version

• Unstable (26.05)

Describe the bug

When rust-bindgen (either our package, or one built within a Rust project) is run to generate bindings with a target triplet that normally requires a different -target flag (and maybe more) to work in Clang/LLVM, Clang is seemingly invoked without these fixes (which are in bash code within our CC-wrapper). This causes the binding generation to fail.

Example in release-cross tests: https://hydra.nixos.org/build/316902609
Also happens when building natively on such a target (ppc64-elfv1 in my case).

Steps to reproduce

nix-build pkgs/top-level/release-cross.nix --arg supportedSystems '[builtins.currentSystem]' -A ppc64-elfv1.mesa

Expected behaviour

The triplet is adjusted to be Clang-understandable before it reaches Clang

Screenshots

n/a

Relevant log output

[425/5415] Generating bindings for Rust src/compiler/rust/rustmod-bindgen-bindings.h
FAILED: [code=1] src/compiler/rust/bindings.rs 
/nix/store/m1ikz2829lxds4bg5krcs4rdi9wzgy37-rust-bindgen-0.72.1/bin/bindgen ../src/compiler/rust/bindings.h --output /build/source/build/src/compiler/rust/bindings.rs --wrap-unsafe-ops --raw-line '#![allow(clippy::all)]' --raw-line '#![allow(improper_ctypes)]' --raw-line '#![allow(unused_unsafe)]' --raw-line '#![allow(non_camel_case_types)]' --raw-line '#![allow(non_snake_case)]' --raw-line '#![allow(non_upper_case_globals)]' --raw-line '#![allow(unsafe_op_in_unsafe_fn)]' --raw-line '#![allow(unnecessary_transmutes)]' --allowlist-var 'NIR_.*' --allowlist-var 'nir_.*_infos' --allowlist-var 'rust_.*' --allowlist-function 'glsl_.*' --allowlist-function _mesa_shader_stage_to_string --allowlist-function 'nir_.*' --allowlist-function 'compiler_rs.*' --allowlist-function 'u_memstream.*' --allowlist-type u_memstream --no-prepend-enum-name --with-derive-default --allowlist-type exec_list --allowlist-type exec_node --allowlist-type float_controls --allowlist-type gc_ctx --allowlist-type gl_access_qualifier --allowlist-type gl_frag_result --allowlist-type gl_interp_mode --allowlist-type mesa_shader_stage --allowlist-type gl_subgroup_size --allowlist-type gl_system_value --allowlist-type gl_tess_spacing --allowlist-type gl_varying_slot --allowlist-type gl_vert_attrib --allowlist-type glsl_type --allowlist-type glsl_matrix_layout --allowlist-type 'nir_.*' --allowlist-type mesa_scope --allowlist-type mesa_prim --allowlist-type mesa_shader_stage --allowlist-type shader_info --allowlist-type tess_primitive_mode --allowlist-type u_printf_info --rust-target 1.91.1 --rust-edition 2021 -- -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS '-DPACKAGE_VERSION="25.3.2"' '-DPACKAGE_BUGREPORT="https://gitlab.freedesktop.org/mesa/mesa/-/issues"' -DHAVE_OPENGL=1 -DHAVE_OPENGL_ES_1=1 -DHAVE_OPENGL_ES_2=1 -DHAVE_ASAHI -DHAVE_CROCUS -DHAVE_D3D12 -DHAVE_ETNAVIV -DHAVE_FREEDRENO -DHAVE_I915 -DHAVE_IRIS -DHAVE_LIMA -DHAVE_LLVMPIPE -DHAVE_NOUVEAU -DHAVE_PANFROST -DHAVE_R300 -DHAVE_R600 -DHAVE_RADEONSI -DHAVE_SOFTPIPE -DHAVE_SVGA -DHAVE_TEGRA -DHAVE_V3D -DHAVE_VC4 -DHAVE_VIRGL -DHAVE_ZINK -DHAVE_ETHOSU -DHAVE_ROCKET -DHAVE_SWRAST -DMESA_SYSTEM_HAS_KMS_DRM=1 -DHAVE_NVK -DVIDEO_CODEC_VC1DEC=1 -DVIDEO_CODEC_H264DEC=1 -DVIDEO_CODEC_H264ENC=1 -DVIDEO_CODEC_H265DEC=1 -DVIDEO_CODEC_H265ENC=1 -DVIDEO_CODEC_AV1DEC=1 -DVIDEO_CODEC_AV1ENC=1 -DVIDEO_CODEC_VP9DEC=1 -DHAVE_X11_PLATFORM -DHAVE_WAYLAND_PLATFORM -DHAVE_SURFACELESS_PLATFORM -DHAVE_DRM_PLATFORM -DHAVE_XCB_PLATFORM -DUSE_LIBGLVND=1 -DUSE_D3D12_PREVIEW_HEADERS=0 -DHAVE_GALLIUM_D3D12_VIDEO -DHAVE_VA_SURFACE_ATTRIB_DRM_FORMAT_MODIFIERS -DGLX_INDIRECT_RENDERING -DGLX_DIRECT_RENDERING -DGLX_USE_DRM -DGLAPI_EXPORT_PROTO_ENTRY_POINTS=0 -DALLOW_KCMP -DMESA_DEBUG=0 -DENABLE_SHADER_CACHE -DHAVE___BUILTIN_BSWAP32 -DHAVE___BUILTIN_BSWAP64 -DHAVE___BUILTIN_CLZ -DHAVE___BUILTIN_CLZLL -DHAVE___BUILTIN_CTZ -DHAVE___BUILTIN_EXPECT -DHAVE___BUILTIN_FFS -DHAVE___BUILTIN_FFSLL -DHAVE___BUILTIN_POPCOUNT -DHAVE___BUILTIN_POPCOUNTLL -DHAVE___BUILTIN_UNREACHABLE -DHAVE___BUILTIN_TYPES_COMPATIBLE_P -DHAVE___BUILTIN_ADD_OVERFLOW -DHAVE___BUILTIN_ADD_OVERFLOW_P -DHAVE___BUILTIN_SUB_OVERFLOW_P -DHAVE_FUNC_ATTRIBUTE_CONST -DHAVE_FUNC_ATTRIBUTE_FLATTEN -DHAVE_FUNC_ATTRIBUTE_MALLOC -DHAVE_FUNC_ATTRIBUTE_PURE -DHAVE_FUNC_ATTRIBUTE_UNUSED -DHAVE_FUNC_ATTRIBUTE_WARN_UNUSED_RESULT -DHAVE_FUNC_ATTRIBUTE_WEAK -DHAVE_FUNC_ATTRIBUTE_FORMAT -DHAVE_FUNC_ATTRIBUTE_PACKED -DHAVE_FUNC_ATTRIBUTE_RETURNS_NONNULL -DHAVE_FUNC_ATTRIBUTE_ALIAS -DHAVE_FUNC_ATTRIBUTE_NORETURN -DHAVE_FUNC_ATTRIBUTE_OPTIMIZE -DHAVE_FUNC_ATTRIBUTE_COLD -DHAVE_FUNC_ATTRIBUTE_VISIBILITY -DHAVE_UINT128 -DHAVE_REALLOCARRAY -DHAVE_FMEMOPEN -D_GNU_SOURCE -DUSE_GCC_ATOMIC_BUILTINS -DMAJOR_IN_SYSMACROS -DHAS_SCHED_H -DHAS_SCHED_GETAFFINITY -DHAVE_LINUX_FUTEX_H -DHAVE_ENDIAN_H -DHAVE_DLFCN_H -DHAVE_SYS_SHM_H -DHAVE_SYS_INOTIFY_H -DHAVE_LINUX_UDMABUF_H -DHAVE_STRTOF -DHAVE_MKOSTEMP -DHAVE_MEMFD_CREATE -DHAVE_RANDOM_R -DHAVE_FLOCK -DHAVE_STRTOK_R -DHAVE_GETRANDOM -DHAVE_POSIX_FALLOCATE -DHAVE_SECURE_GETENV -DHAVE_SYSCONF -DHAVE_GNU_QSORT_R -DHAVE_STRUCT_TIMESPEC -DHAVE_PROGRAM_INVOCATION_NAME -DHAVE_ISSIGNALING -DHAVE_POSIX_MEMALIGN -DHAVE_DIRENT_D_TYPE -DHAVE_STRTOD_L -DHAVE_DLADDR -DHAVE_DL_ITERATE_PHDR -DHAVE_ZLIB -DHAVE_LIBDISPLAY_INFO -DHAVE_ZSTD -DHAVE_COMPRESSION -DHAVE_PTHREAD -DHAVE_PTHREAD_SETAFFINITY -DHAVE_LIBDRM -DHAVE_LIBUDEV '-DMESA_LLVM_VERSION_STRING="21.1.2"' -DLLVM_IS_SHARED=1 -DDRAW_LLVM_AVAILABLE=1 -DAMD_LLVM_AVAILABLE=1 -DGALLIVM_USE_ORCJIT=0 -DHAVE_SPIRV_TOOLS -DUSE_LIBELF -DHAVE_VALGRIND -DTHREAD_SANITIZER=0 -DHAVE_LIBUNWIND -DWL_HIDE_DEPRECATED -DHAVE_WL_DISPATCH_QUEUE_TIMEOUT -DHAVE_WL_CREATE_QUEUE_WITH_NAME -DXCB_KEYSYMS_AVAILABLE -DHAVE_X11_DRM -DHAVE_DRI -DHAVE_DRI2 -DHAVE_DRI3_EXPLICIT_SYNC -DHAVE_DRISW_KMS -DHAVE_GALLIUM_EXTRA_HUD=1 -DHAVE_LIBSENSORS=1 -DANDROID_LIBPERFETTO -target powerpc64-unknown-linux-gnuabielfv1 -DNDEBUG -I/build/source/src/compiler/nir/. -I/build/source/build/src/compiler/nir/. -I/build/source/src/compiler/. -I/build/source/build/src/compiler/. -I/build/source/src/. -I/build/source/build/src/. -I/build/source/include/. -I/build/source/build/include/. -I/build/source/include/. -I/build/source/build/include/. -I/build/source/src/util/.. -I/build/source/build/src/util/.. -I/nix/store/3mxyj2yfaz6aml43d5r2x9sc3zx4m7dw-zlib-powerpc64-unknown-linux-gnuabielfv1-1.3.1-dev/include -pthread -I/nix/store/zkhag867rjznad9jbxsl55ixf9jzgnfi-valgrind-powerpc64-unknown-linux-gnuabielfv1-3.26.0-dev/include/valgrind -I/nix/store/hjy9jiffr08h1ila954hxzrwd7j8fq4l-zstd-powerpc64-unknown-linux-gnuabielfv1-1.5.7-dev/include -I/nix/store/133xg07aczk6pag4bxa8cyw0sgkg3231-libunwind-powerpc64-unknown-linux-gnuabielfv1-1.8.3-dev/include -pthread -I/nix/store/zkhag867rjznad9jbxsl55ixf9jzgnfi-valgrind-powerpc64-unknown-linux-gnuabielfv1-3.26.0-dev/include/valgrind -I/nix/store/nhqamw4g23hyz8f59hgvgdz3h5f3847m-libdrm-powerpc64-unknown-linux-gnuabielfv1-2.4.128-dev/include -I/nix/store/nhqamw4g23hyz8f59hgvgdz3h5f3847m-libdrm-powerpc64-unknown-linux-gnuabielfv1-2.4.128-dev/include/libdrm -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS '-DPACKAGE_VERSION="25.3.2"' '-DPACKAGE_BUGREPORT="https://gitlab.freedesktop.org/mesa/mesa/-/issues"' -DHAVE_OPENGL=1 -DHAVE_OPENGL_ES_1=1 -DHAVE_OPENGL_ES_2=1 -DHAVE_ASAHI -DHAVE_CROCUS -DHAVE_D3D12 -DHAVE_ETNAVIV -DHAVE_FREEDRENO -DHAVE_I915 -DHAVE_IRIS -DHAVE_LIMA -DHAVE_LLVMPIPE -DHAVE_NOUVEAU -DHAVE_PANFROST -DHAVE_R300 -DHAVE_R600 -DHAVE_RADEONSI -DHAVE_SOFTPIPE -DHAVE_SVGA -DHAVE_TEGRA -DHAVE_V3D -DHAVE_VC4 -DHAVE_VIRGL -DHAVE_ZINK -DHAVE_ETHOSU -DHAVE_ROCKET -DHAVE_SWRAST -DMESA_SYSTEM_HAS_KMS_DRM=1 -DHAVE_NVK -DVIDEO_CODEC_VC1DEC=1 -DVIDEO_CODEC_H264DEC=1 -DVIDEO_CODEC_H264ENC=1 -DVIDEO_CODEC_H265DEC=1 -DVIDEO_CODEC_H265ENC=1 -DVIDEO_CODEC_AV1DEC=1 -DVIDEO_CODEC_AV1ENC=1 -DVIDEO_CODEC_VP9DEC=1 -DHAVE_X11_PLATFORM -DHAVE_WAYLAND_PLATFORM -DHAVE_SURFACELESS_PLATFORM -DHAVE_DRM_PLATFORM -DHAVE_XCB_PLATFORM -DUSE_LIBGLVND=1 -DUSE_D3D12_PREVIEW_HEADERS=0 -DHAVE_GALLIUM_D3D12_VIDEO -DHAVE_VA_SURFACE_ATTRIB_DRM_FORMAT_MODIFIERS -DGLX_INDIRECT_RENDERING -DGLX_DIRECT_RENDERING -DGLX_USE_DRM -DGLAPI_EXPORT_PROTO_ENTRY_POINTS=0 -DALLOW_KCMP -DMESA_DEBUG=0 -DENABLE_SHADER_CACHE -DHAVE___BUILTIN_BSWAP32 -DHAVE___BUILTIN_BSWAP64 -DHAVE___BUILTIN_CLZ -DHAVE___BUILTIN_CLZLL -DHAVE___BUILTIN_CTZ -DHAVE___BUILTIN_EXPECT -DHAVE___BUILTIN_FFS -DHAVE___BUILTIN_FFSLL -DHAVE___BUILTIN_POPCOUNT -DHAVE___BUILTIN_POPCOUNTLL -DHAVE___BUILTIN_UNREACHABLE -DHAVE___BUILTIN_TYPES_COMPATIBLE_P -DHAVE___BUILTIN_ADD_OVERFLOW -DHAVE___BUILTIN_ADD_OVERFLOW_P -DHAVE___BUILTIN_SUB_OVERFLOW_P -DHAVE_FUNC_ATTRIBUTE_CONST -DHAVE_FUNC_ATTRIBUTE_FLATTEN -DHAVE_FUNC_ATTRIBUTE_MALLOC -DHAVE_FUNC_ATTRIBUTE_PURE -DHAVE_FUNC_ATTRIBUTE_UNUSED -DHAVE_FUNC_ATTRIBUTE_WARN_UNUSED_RESULT -DHAVE_FUNC_ATTRIBUTE_WEAK -DHAVE_FUNC_ATTRIBUTE_FORMAT -DHAVE_FUNC_ATTRIBUTE_PACKED -DHAVE_FUNC_ATTRIBUTE_RETURNS_NONNULL -DHAVE_FUNC_ATTRIBUTE_ALIAS -DHAVE_FUNC_ATTRIBUTE_NORETURN -DHAVE_FUNC_ATTRIBUTE_OPTIMIZE -DHAVE_FUNC_ATTRIBUTE_COLD -DHAVE_FUNC_ATTRIBUTE_VISIBILITY -DHAVE_UINT128 -DHAVE_REALLOCARRAY -DHAVE_FMEMOPEN -D_GNU_SOURCE -DUSE_GCC_ATOMIC_BUILTINS -DMAJOR_IN_SYSMACROS -DHAS_SCHED_H -DHAS_SCHED_GETAFFINITY -DHAVE_LINUX_FUTEX_H -DHAVE_ENDIAN_H -DHAVE_DLFCN_H -DHAVE_SYS_SHM_H -DHAVE_SYS_INOTIFY_H -DHAVE_LINUX_UDMABUF_H -DHAVE_STRTOF -DHAVE_MKOSTEMP -DHAVE_MEMFD_CREATE -DHAVE_RANDOM_R -DHAVE_FLOCK -DHAVE_STRTOK_R -DHAVE_GETRANDOM -DHAVE_POSIX_FALLOCATE -DHAVE_SECURE_GETENV -DHAVE_SYSCONF -DHAVE_GNU_QSORT_R -DHAVE_STRUCT_TIMESPEC -DHAVE_PROGRAM_INVOCATION_NAME -DHAVE_ISSIGNALING -DHAVE_POSIX_MEMALIGN -DHAVE_DIRENT_D_TYPE -DHAVE_STRTOD_L -DHAVE_DLADDR -DHAVE_DL_ITERATE_PHDR -DHAVE_ZLIB -DHAVE_LIBDISPLAY_INFO -DHAVE_ZSTD -DHAVE_COMPRESSION -DHAVE_PTHREAD -DHAVE_PTHREAD_SETAFFINITY -DHAVE_LIBDRM -DHAVE_LIBUDEV '-DMESA_LLVM_VERSION_STRING="21.1.2"' -DLLVM_IS_SHARED=1 -DDRAW_LLVM_AVAILABLE=1 -DAMD_LLVM_AVAILABLE=1 -DGALLIVM_USE_ORCJIT=0 -DHAVE_SPIRV_TOOLS -DUSE_LIBELF -DHAVE_VALGRIND -DTHREAD_SANITIZER=0 -DHAVE_LIBUNWIND -DWL_HIDE_DEPRECATED -DHAVE_WL_DISPATCH_QUEUE_TIMEOUT -DHAVE_WL_CREATE_QUEUE_WITH_NAME -DXCB_KEYSYMS_AVAILABLE -DHAVE_X11_DRM -DHAVE_DRI -DHAVE_DRI2 -DHAVE_DRI3_EXPLICIT_SYNC -DHAVE_DRISW_KMS -DHAVE_GALLIUM_EXTRA_HUD=1 -DHAVE_LIBSENSORS=1 -DANDROID_LIBPERFETTO -std=c11 -MD -MQ ../src/compiler/rust/bindings.h -MF src/compiler/rust/bindings.h.d
Unable to generate bindings: clang diagnosed error: error: version 'abielfv1' in target triple 'powerpc64-unknown-linux-gnuabielfv1' is invalid

Additional context

On glibc ppc64, we use powerpc64-unknown-linux-gnuabielfv1 or powerpc64-unknown-linux-gnuabielfv2 triplets. We go out of our way to reject powerpc64-unknown-linux-gnu because on this platform, it's too vague about which ELF ABI should be used.

nixpkgs/lib/systems/parse.nix

Lines 699 to 704 in 45b438f

	{
	assertion = platform: !(platform.isPower64 && platform.isBigEndian);
	message = ''
	The "gnu" ABI is ambiguous on big-endian 64-bit PowerPC. Use "gnuabielfv2" or "gnuabielfv1" instead.
	'';
	}

GCC understands these triplets, but Clang doesn't. For Clang, we provide a translation of the triplet into -target ...-gnu -mabi=elfv[1/2] in the CC wrapper.

nixpkgs/pkgs/build-support/cc-wrapper/default.nix

Lines 936 to 957 in 45b438f

	##
	## General Clang support
	## Needs to go after ^ because the for loop eats \n and makes this file an invalid script
	##
	+ optionalString isClang (
	let
	hasUnsupportedGnuSuffix = hasPrefix "gnuabielfv" targetPlatform.parsed.abi.name;
	clangCompatibleConfig =
	if hasUnsupportedGnuSuffix then
	removeSuffix (removePrefix "gnu" targetPlatform.parsed.abi.name) targetPlatform.config
	else
	targetPlatform.config;
	explicitAbiValue = if hasUnsupportedGnuSuffix then targetPlatform.parsed.abi.abi else "";
	in
	''
	# Escape twice: once for this script, once for the one it gets substituted into.
	export machineFlags=${escapeShellArg (escapeShellArgs machineFlags)}
	export defaultTarget=${clangCompatibleConfig}
	export explicitAbiValue=${explicitAbiValue}
	substituteAll ${./add-clang-cc-cflags-before.sh} $out/nix-support/add-local-cc-cflags-before.sh
	''
	)

nixpkgs/pkgs/build-support/cc-wrapper/add-clang-cc-cflags-before.sh

Lines 29 to 37 in 45b438f

	if $targetPassed && [[ "$targetValue" != "@defaultTarget@" ]] && (( "${NIX_CC_WRAPPER_SUPPRESS_TARGET_WARNING:-0}" < 1 )); then
	echo "Warning: supplying the --target $targetValue != @defaultTarget@ argument to a nix-wrapped compiler may not work correctly - cc-wrapper is currently not designed with multi-target compilers in mind. You may want to use an un-wrapped compiler instead." >&2
	elif [[ $0 != *cpp ]]; then
	extraBefore+=(-target @defaultTarget@ @machineFlags@)
	if [[ "@explicitAbiValue@" != "" ]]; then
	extraBefore+=(-mabi=@explicitAbiValue@)
	fi
	fi

Similarly for Rust.

nixpkgs/lib/systems/default.nix

Lines 478 to 512 in 45b438f

	# The name of the rust target, even if it is custom. Adjustments are
	# because rust has slightly different naming conventions than we do.
	rustcTarget =
	let
	inherit (final.parsed) cpu kernel abi;
	cpu_ =
	rust.platform.arch or {
	"armv7a" = "armv7";
	"armv7l" = "armv7";
	"armv6l" = "arm";
	"armv5tel" = "armv5te";
	"riscv32" = "riscv32gc";
	"riscv64" = "riscv64gc";
	}
	.${cpu.name} or cpu.name;
	vendor_ = final.rust.platform.vendor;
	abi_ =
	# We're very explicit about the POWER ELF ABI w/ glibc in our parsing, while Rust is not.
	# TODO: Somehow ensure that Rust actually *uses* the correct ABI, and not just a libc-based default.
	if (lib.strings.hasPrefix "powerpc" cpu.name) && (lib.strings.hasPrefix "gnuabielfv" abi.name) then
	"gnu"
	else
	abi.name;
	in
	# TODO: deprecate args.rustc in favour of args.rust after 23.05 is EOL.
	args.rust.rustcTarget or args.rustc.config or (
	# Rust uses `wasm32-wasip?` rather than `wasm32-unknown-wasi`.
	# We cannot know which subversion does the user want, and
	# currently use WASI 0.1 as default for compatibility. Custom
	# users can set `rust.rustcTarget` to override it.
	if final.isWasi then
	"${cpu_}-wasip1"
	else
	"${cpu_}-${vendor_}-${kernel.name}${optionalString (abi.name != "unknown") "-${abi_}"}"
	);

But for calls from rust-bindgen to Clang, this fixup seems to be missing & results in our normal triplet being used, hence the error?

System metadata

• system: "x86_64-linux"
• host os: Linux 6.18.1, NixOS, 25.11 (Xantusia), 25.11.1948.c6f52ebd45e5
• multi-user?: yes
• sandbox: yes
• version: nix-env (Lix, like Nix) 2.94.0 System type: x86_64-linux Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /home/puna/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/puna/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/puna/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/puna/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf:/nix/store/2v5idvgi7496akyxzk6030853sl8bw6b-gnome-settings-daemon-49.1/etc/xdg/nix/nix.conf:/nix/store/2v5idvgi7496akyxzk6030853sl8bw6b-gnome-settings-daemon-49.1/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/aijhgvgyw36h9vr6l6grclz3q35283yq-lix-2.94.0/share
• channels(bt1cn): "unstable"
• channels(root): "nixos-25.11, unstable"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

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@JohnTitor

---

Note for maintainers: Please tag this issue in your pull request description. (i.e. Resolves #ISSUE.)

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[alyssais]

Sounds like a fix is needed in pkgs/build-support/lib/meson.nix?

[OPNA2608]

diff --git a/pkgs/development/tools/rust/bindgen/default.nix b/pkgs/development/tools/rust/bindgen/default.nix
index 393b89a4acb4..dc913b887a09 100644
--- a/pkgs/development/tools/rust/bindgen/default.nix
+++ b/pkgs/development/tools/rust/bindgen/default.nix
@@ -1,4 +1,6 @@
 {
+  stdenv,
+  lib,
   rust-bindgen-unwrapped,
   zlib,
   bash,
@@ -7,6 +9,13 @@
 }:
 let
   clang = rust-bindgen-unwrapped.clang;
+  hasUnsupportedGnuSuffix = lib.hasPrefix "gnuabielfv" stdenv.targetPlatform.parsed.abi.name;
+  clangCompatibleConfig =
+    if hasUnsupportedGnuSuffix then
+      lib.removeSuffix (lib.removePrefix "gnu" stdenv.targetPlatform.parsed.abi.name) stdenv.targetPlatform.config
+    else
+      stdenv.targetPlatform.config;
+  explicitAbiValue = if hasUnsupportedGnuSuffix then stdenv.targetPlatform.parsed.abi.abi else "";
   self =
     runCommand "rust-bindgen-${rust-bindgen-unwrapped.version}"
       {
@@ -49,7 +58,9 @@ let
           --replace-fail "@bash@" "${bash}" \
           --replace-fail "@cxxincludes@" "$cxxincludes" \
           --replace-fail "@cincludes@" "$cincludes" \
-          --replace-fail "@unwrapped@" "${rust-bindgen-unwrapped}"
+          --replace-fail "@unwrapped@" "${rust-bindgen-unwrapped}" \
+          --replace-fail "@defaultTarget@" "${clangCompatibleConfig}" \
+          --replace-fail "@explicitAbiValue@" "${explicitAbiValue}"
         chmod +x $out/bin/bindgen
       '';
 in
diff --git a/pkgs/development/tools/rust/bindgen/wrapper.sh b/pkgs/development/tools/rust/bindgen/wrapper.sh
index 4311b9720aa8..d041ac1aadc9 100755
--- a/pkgs/development/tools/rust/bindgen/wrapper.sh
+++ b/pkgs/development/tools/rust/bindgen/wrapper.sh
@@ -27,8 +27,13 @@ fi;
 if [[ -n "$NIX_DEBUG" ]]; then
   set -x;
 fi;
+targetflags="-target @defaultTarget@"
+explicitAbiValue="@explicitAbiValue@"
+if [[ -n "$explicitAbiValue" ]]; then
+  targetflags="$targetflags -mabi=$explicitAbiValue"
+fi
 # shellcheck disable=SC2086
 # cxxflags and NIX_CFLAGS_COMPILE should be word-split
-exec -a "$0" @unwrapped@/bin/bindgen "$@" $sep $cxxflags @cincludes@ $NIX_CFLAGS_COMPILE
+exec -a "$0" @unwrapped@/bin/bindgen "$@" $sep $cxxflags @cincludes@ $targetflags $NIX_CFLAGS_COMPILE
 # note that we add the flags after $@ which is incorrect. This is only for the sake
 # of simplicity.

This (basically copy-pasting what cc-wrapper is doing, but without the check for an already-supplied -(-)target flag) seems to get pkgsCross.ppc64-elfv1.mesa as far as it currently does on hardware (#456839). I feel like the lack of yielding to an already-supplied -(-)target could cause issues though…

[alyssais]

So far we have considered it the responsibility of the build system to pass target flags to bindgen (hence us setting this up in the Meson cross file), rather than the wrapper. From memory quite a lot of thought went into doing it that way and I proposed doing it in the bindgen wrapper initially.