arch/x86: default CROSSDEV on a macOS host - #19567
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arch/x86 set CROSSDEV only under Cygwin, so everywhere else the build used the bare tool names and got the host compiler. On Linux that is a native gcc which can produce i486 ELF objects, which is what the board README assumes. On macOS it is Apple clang, and on Apple Silicon that cannot target i386 in any form -- so there is no configuration in which the default works and a cross toolchain is not optional. Default it to i686-elf-, which Homebrew packages and which accepts the -march=i486 -mtune=i486 already in ARCHCPUFLAGS. arch/x86_64 has had exactly this stanza for its own toolchain all along; this is the same shape. The Cygwin assignment becomes ?= to match, so that a CROSSDEV passed in from the environment or the command line is honoured rather than overridden. Note for anyone tempted by the toolchain they already have: a 64-bit x86 compiler with -m32 is not a substitute unless it was built with multilib. Homebrew's x86_64-elf-gcc compiles 32-bit objects perfectly happily and has no 32-bit libgcc to link them against, so the entire build succeeds and only the final link fails, on __udivdi3, __divdi3, __moddi3 and __udivmoddi4. `x86_64-elf-gcc -print-multi-lib' prints just `.;', which is the toolchain saying so up front. Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Done The two comment blocks are merged into one above it. Re-verified after the change: |
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please replace
Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com
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Assisted-by: Claude Opus 5 (1M context) noreply@anthropic.com
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@jerpelea hello can you please re-review? |
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Summary
arch/x86/src/common/Toolchain.defssetsCROSSDEVonly under Cygwin:Everywhere else
CROSSDEVis empty, soCCbecomes the bare hostgcc. Thatis fine on an x86 Linux box and useless anywhere else. On macOS the host
compiler is Apple clang, which on Apple Silicon cannot target i386 at all, so
the build fails in a thoroughly misleading way — the ARM assembler rejecting
x86 inline asm out of an x86 header:
This gives
CROSSDEVa sane default on macOS and makes the Cygwin oneoverridable (
=→?=), matching whatarch/x86_64already does.Homebrew's
i686-elf-gccis the intended target; a 64-bit x86 toolchain with-m32is not a substitute unless built with multilib, since it compiles 32-bitobjects and then has no 32-bit libgcc to link them against — which surfaces
only at the final link as undefined
__udivdi3and friends.Impact
Only
CONFIG_HOST_MACOS=ybuilds ofarch/x86change, and only by picking acompiler that can actually target the architecture.
?=keeps any existingoverride — including the Cygwin default — working.
Testing
qemu-i486:nshon macOS 15 / Apple Silicon, Homebrewi686-elf-gcc16.1.0:i686-elf-gccis invoked and the build completes — rc 0, 3.0 MBnuttx.elf.One caveat worth recording for anyone reproducing this: the shipped
qemu-i486:nshdefconfig setsCONFIG_LIBM_TOOLCHAIN=y, which defersmath.hto the toolchain, and Homebrew's
i686-elf-gccis bare-metal with no newlibheaders. Selecting NuttX's own
CONFIG_LIBM=yinstead builds cleanly. That isindependent of this change and is not addressed here.
tools/checkpatch.sh -c -u -m -gclean.