jingfei195887 opened a new pull request, #20628:
URL: https://github.com/apache/nuttx/pull/20628
## Summary
Related to the footprint discussion in #20414. Three small, independent
changes that let size-constrained configurations drop code that currently
cannot be trimmed. Default (non-`DEFAULT_SMALL`) builds keep today's
behavior.
1. **mm/mm_heap: optional inline for `mm_addfreechunk()`**
`mm_addfreechunk()` walks the free list and is inlined into every heap
path
(malloc, free, realloc, shrinkchunk, initialize), so each caller carries
its
own copy of the loop. New `CONFIG_MM_INLINE_ADDFREECHUNK`
(`default !DEFAULT_SMALL`). When disabled, `mm_addfreechunk.c` emits one
shared copy. The function body stays in one place (`mm.h`); the `.c` only
instantiates it, so no code is duplicated.
2. **sched: optional inline for `nxsched_add_prioritized()`**
Inlined into all 18 call sites across the scheduler, semaphores, message
queues and events. New `CONFIG_SCHED_INLINE_ADDPRIORITIZED`
(`default !DEFAULT_SMALL`), same single-body pattern via
`sched_addprioritized.c`.
3. **libc: build `lib_cxx_initialize()` only for C++ init**
Without `CONFIG_HAVE_CXXINITIALIZE` the function body compiles away, but
the
empty function and its call from `nxtask_startup()` remain. The file is
now
built only when C++ static initialization is supported; otherwise the call
is a no-op macro.
Items 1 and 2 were made inline for performance in #14144 and #14059. That
stays the default; only `DEFAULT_SMALL` builds switch to the shared copy.
## Impact
- Default builds: no functional or size change from items 1 and 2. Both new
options default to `y` unless `CONFIG_DEFAULT_SMALL=y`.
- `DEFAULT_SMALL` builds: one extra call/return on heap free-list insertion
and
on priority-list insertion, in exchange for code size.
- No API or ABI change. `lib_cxx_initialize()` is libc-internal
(`libs/libc/libc.h`).
- Make and CMake are both updated.
## Testing
Host: Ubuntu x86_64, arm-none-eabi-gcc 10.3.1 20210621. Rebased on master
`734b0c5757`. All sizes below come from clean CMake builds.
**Size, `stm32f103-minimum:nsh` (`DEFAULT_SMALL=y`):**
| | text | data | bss |
|---|---:|---:|---:|
| master (734b0c5757) | 51975 | 468 | 2952 |
| this PR | 51399 | 468 | 2952 |
| **delta** | **-576** | 0 | 0 |
Per commit, applied in order: `mm_addfreechunk` -360,
`nxsched_add_prioritized`
-200, `lib_cxx_initialize` -16.
**Both states of each option build**, and the out-of-line symbol is present
only when the option is off:
| configuration (at this PR) | text | out-of-line symbols |
|---|---:|---|
| defaults (`DEFAULT_SMALL=y`, both inline options off) | 51399 |
`mm_addfreechunk`, `nxsched_add_prioritized` |
| `MM_INLINE_ADDFREECHUNK=y`, `SCHED_INLINE_ADDPRIORITIZED=y` | 51967 | none
|
| `HAVE_CXXINITIALIZE=y` | 51455 | `lib_cxx_initialize` linked |
Other checks:
- `sim:smp` with both inline options off: builds; one shared copy of each
function.
- `./tools/checkpatch.sh -g master..HEAD`: all checks pass. `cmake-format
--check`: clean.
**Runtime, `sim:ostest`:** run with both inline options off and, as a
control,
with both on (same tree). Both runs reached `waitpid_test` inside a 540 s
timeout with no `ERROR`, assertion or panic, and went through the same tests.
Neither configuration finished ostest in that window, so this shows no
difference between the two configurations rather than a full ostest pass.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
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