diff mbox series

classes/meson: fix bindgen_clang_args when default toolchain is not clang

Message ID 20260212-mesa-opencl-big-little-v1-1-7f328328d149@cherry.de
State New
Headers show
Series classes/meson: fix bindgen_clang_args when default toolchain is not clang | expand

Commit Message

Quentin Schulz Feb. 12, 2026, 5:53 p.m. UTC 
From: Quentin Schulz <quentin.schulz@cherry.de>

We generate a wrapper for bindgen arguments when building with clang but
we don't actually use clang variants of variables when generating the
wrapper.

The default toolchain may not be clang, therefore TCOVERRIDE will be set
to that toolchain instead and if variables have variants per toolchain,
the one for the default toolchain will be used instead of the one for
clang.

This is an issue that can be highlighted by trying to build rusticl
OpenCL mesa driver while the default toolchain is GCC and for an ARM
big.LITTLE architecture (e.g. cortex-a76.cortex-a55). Most mesa drivers
can be built with either GCC or clang but rusticl OpenCL driver must be
built with clang for now.
clang toolchain doesn't actually support the big.LITTLE architecture at
all and must build for the LITTLE part of it (cortex-a55). This is
currently handled by the CPU_TUNE_ARG variable in the impacted CPU
include configuration files. Until now, the GCC variant would be used
and the flags would contain -mcpu=cortexa-76.cortex-a55, failing the
build.

After this patch, clang-specific variables can be used and this will
result in the bindgen flags having e.g. -mcpu=cortex-a55 instead.

This fixes mesa's rusticl build on Rockchip RK3399 and RK3588 big.LITTLE
SoCs.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
---
This was tested on top of a local branch with mesa-26.0.0 recipe. Only
tested with mesa (and any of its dependencies using meson I guess). I
can now have clpeak running on my RK3588 boards and mostly working on my
RK3399 (the GPU scheduler times out for float16 Global memory bandwidth
(GBPS) benchmark but all the other tests seem to be working fine). Note
you must set RUSTICL_ENABLE environment variable to panfrost otherwise
it won't work.
---
 meta/classes-recipe/meson.bbclass | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)


---
base-commit: 3a8f0075d52cb653118774baa03aa8d5231f943c
change-id: 20260212-mesa-opencl-big-little-89c77def7294

Best regards,
--  
Quentin Schulz <quentin.schulz@cherry.de>
diff mbox series

Patch

diff --git a/meta/classes-recipe/meson.bbclass b/meta/classes-recipe/meson.bbclass
index 2c098771fe..ce607703e3 100644
--- a/meta/classes-recipe/meson.bbclass
+++ b/meta/classes-recipe/meson.bbclass
@@ -58,11 +58,30 @@  def rust_tool(d, target_var):
     return "rust = %s" % repr(cmd)
 
 def bindgen_args(d):
+    # Variables may have clang-specific values and this function is only called
+    # for bindgen_clang_args, meaning the args must be the ones used by clang.
+    # The default toolchain may not be clang and some recipes may use two
+    # toolchains (e.g. mesa rusticl/gallium-llvm requires clang but not the
+    # other drivers in the recipe).
+    # This is necessary for example for ARM big.LITTLE CPU architecture where
+    # -mcpu will be set to e.g. cortex-a76.cortex-a55 for GCC but clang doesn't
+    # support big.LITTLE so we need to have cortex-a55 only, see CPU_TUNE_ARG
+    # variable.
+    # Therefore, to know which parameters bindgen must use with clang, we
+    # simulate using clang by setting the TCOVERRIDE to toolchain-clang
+    # temporarily.
+    # This is of course unnecessary if the default toolchain is already clang.
+    if d.getVar('TCOVERRIDE') != 'toolchain-clang':
+        localdata = bb.data.createCopy(d)
+        localdata.setVar('TCOVERRIDE', 'toolchain-clang')
+    else:
+        localdata = d
+
     args = '${HOST_CC_ARCH}${TOOLCHAIN_OPTIONS} --target=${TARGET_SYS}'
     # For SDK packages TOOLCHAIN_OPTIONS don't contain full sysroot path
-    if bb.data.inherits_class("nativesdk", d):
+    if bb.data.inherits_class("nativesdk", localdata):
         args += ' --sysroot=${STAGING_DIR_HOST}${SDKPATHNATIVE}${prefix_nativesdk}'
-    items = d.expand(args).split()
+    items = localdata.expand(args).split()
     return repr(items[0] if len(items) == 1 else items)
 
 addtask write_config before do_configure