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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>
93 lines
3.2 KiB
C
93 lines
3.2 KiB
C
/****************************************************************************
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* libs/libc/misc/lib_cxx_initialize.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/arch.h>
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#include <assert.h>
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#include <nuttx/debug.h>
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#include <sched.h>
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#include <stdlib.h>
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#include "libc.h"
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/****************************************************************************
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* External References
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lib_cxx_initialize
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*
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* Description:
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* If C++ and C++ static constructors are supported, then this function
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* must be provided by board-specific logic in order to perform
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* initialization of the static C++ class instances.
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*
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* This function should then be called in the application-specific
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* user_start logic in order to perform the C++ initialization. NOTE
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* that no component of the core NuttX RTOS logic is involved; this
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* function definition only provides the 'contract' between application
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* specific C++ code and platform-specific toolchain support.
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*
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****************************************************************************/
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void lib_cxx_initialize(void)
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{
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#ifdef CONFIG_HAVE_CXXINITIALIZE
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static int inited = 0;
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if (inited == 0)
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{
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initializer_t *initp;
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sinfo("_sinit: %p _einit: %p\n", _sinit, _einit);
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/* Visit each entry in the initialization table */
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for (initp = _sinit; initp < _einit; initp++)
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{
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initializer_t initializer = *initp;
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sinfo("initp: %p initializer: %p\n", initp, initializer);
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/* Make sure that the address is non-NULL. Some toolchains may put
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* NULL values or counts in the initialization table.
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*/
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if (initializer)
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{
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sinfo("Calling %p\n", initializer);
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initializer();
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}
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}
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inited = 1;
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}
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#endif
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}
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