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Xiang Xiao 754dfd980b arch/sim: replace macOS C++ constructor runtime hack with post-link patch
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>
2026-05-19 07:08:55 -03:00
.github ci: retry git clone for nuttx-ntfc-testing 2026-05-12 08:45:30 -03:00
arch arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
audio include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
binfmt include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
boards boards/risc-v/esp32p4: Add touch sensor board support for esp32[-p4] 2026-05-19 16:38:16 +08:00
cmake cmake: Moved the creation of the nxtmpdir folder to the root CMake file 2026-04-22 06:22:36 +08:00
crypto !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
Documentation Docs/platforms/esp32p4: Add touch sensor docs 2026-05-19 16:38:16 +08:00
drivers !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
dummy
fs !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
graphics include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
include !sys/types.h: change time_t and clock_t to int64_t to align with other OSes 2026-05-19 16:21:28 +08:00
libs arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
mm !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
net !sys/types.h: change time_t and clock_t to int64_t to align with other OSes 2026-05-19 16:21:28 +08:00
openamp openamp: fix CMake dcache option 2026-05-10 15:03:24 +02:00
pass1 Makefile: Remove make depend files by make distclean 2026-02-16 16:27:57 +01:00
sched !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
syscall syscall: fcntl param3 type to uintptr_t 2026-04-27 12:01:55 -03:00
tools board: enable LTO on g431 nsh boards and fix LTO link with toolchain switch 2026-05-19 16:21:28 +08:00
video video: ensure video library is non-empty 2026-05-08 19:51:39 +08:00
wireless include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
.codespellrc arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore arch/*/src/Makefile: Avoid uncessary relinking of the nuttx binary. 2026-05-18 09:33:58 +02:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint
AUTHORS AUTHORS: add Donny Jiuzhu 2026-02-25 10:17:40 +01:00
CMakeLists.txt cmake: Moved the creation of the nxtmpdir folder to the root CMake file 2026-04-22 06:22:36 +08:00
CONTRIBUTING.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
INVIOLABLES.md
Kconfig tools/stackusage.py: use toolchain binaries instead of Python libraries 2026-03-17 11:26:44 -03:00
LICENSE !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
Makefile tools: migrate to SPDX identifier 2024-09-10 23:11:11 +08:00
NOTICE
README.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

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