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754dfd980b
The sim architecture needs to defer C++ global constructors until after
NuttX kernel initialization completes. On macOS this was previously done
via a runtime hack (sim_macho_init.c): a __attribute__((constructor))
function intercepted constructors, saved them, and replayed them later.
That approach was fragile because it depended on constructor ordering
and required mprotect() to patch the read-only __mod_init_func section
at runtime.
This commit replaces the runtime hack with a post-link patching scheme:
1. Link with -Wl,-ld_classic,-no_fixup_chains to keep the classic
__mod_init_func pointer format (prevents ld64 from converting it
to __init_offsets).
2. Post-link, run patch_macho_initsection.py (python3 + lief) to
patch Mach-O section type flags from
MOD_INIT_FUNC_POINTERS/INIT_FUNC_OFFSETS to REGULAR, so dyld
skips them entirely.
3. Use the Mach-O auto-generated boundary symbols
section$start$__DATA_CONST$__mod_init_func /
section$end$__DATA_CONST$__mod_init_func, mapped via __asm()
labels in arch/sim/include/arch.h to the common _sinit[]/_einit[]
names used by lib_cxx_initialize().
Linux behavior is unchanged.
Changes:
- arch/sim/include/arch.h: add macOS __asm() declarations for
_sinit/_einit
- arch/sim/src/Makefile: drop sim_macho_init.c HEADSRC handling,
always pass -ld_classic,-no_fixup_chains on macOS, run
patch_macho_initsection.py after link when CONFIG_HAVE_CXXINITIALIZE
- arch/sim/src/sim/CMakeLists.txt: same for the CMake build
- arch/sim/src/patch_macho_initsection.py: new lief-based patcher
- arch/sim/src/sim/posix/sim_macho_init.c: deleted (135-line hack)
- libs/libc/misc/lib_cxx_initialize.c: remove
macho_call_saved_init_funcs special case; single unified loop
Testing:
- macOS (Ventura VM): verified lief patching with standalone test
(test_sinit7) confirming the constructor is deferred past main()
and only invoked when explicitly called via the _sinit/_einit loop.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
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| .. | ||
| sim | ||
| .gitignore | ||
| arch.h | ||
| elf.h | ||
| inttypes.h | ||
| irq.h | ||
| limits.h | ||
| setjmp.h | ||
| spinlock.h | ||
| syscall.h | ||
| types.h | ||