jingfei195887 opened a new pull request, #20690:
URL: https://github.com/apache/nuttx/pull/20690
## Summary
Related to the footprint discussion in #20414. Two small changes in
`sched/misc/coredump.c`:
1. **Mark `elf_emit()` and `elf_emit_align()` `noinline_function`.** They are
called from every part of the dump (ELF header, program headers, notes,
stacks, memory regions). At `-O2` GCC inlines them into each caller. The
crash path is not performance sensitive, so one shared copy is enough.
2. **Look up the dumped task's TCB once.** When a single task is dumped
(`pid != INVALID_PROCESS_ID`), `coredump()` already looks up the TCB to
validate the PID, and then `elf_emit_phdr()`, `elf_emit_note()` and
`elf_emit_stack()` each look it up again. The TCB is now kept in
`elf_dumpinfo_s` and reused. The whole dump runs inside one critical
section, so the TCB cannot go away in between.
## Impact
No functional change. The dump format and content are unchanged.
## Testing
Host: Ubuntu x86_64, arm-none-eabi-gcc 10.3.1 20210621, master 7d65bf6dde,
clean CMake builds. Flash = text + data.
| build | master | this PR | delta |
|---|---:|---:|---:|
| `stm32f103-minimum:nsh` + `COREDUMP` + `BOARD_COREDUMP_SYSLOG`, `-Os` |
54199 | 54191 | **-8** |
| same, `-O2` | 62095 | 61887 | **-208** |
| `sabre-6quad:coredump` (SMP, `-Os`) | 199088 | 199088 | 0 |
Runtime: `qemu-armv7a:nsh` with `COREDUMP`, `BOARD_COREDUMP_SYSLOG` and
`SYSTEM_COREDUMP`, master and this PR side by side. `coredump -p 0`,
`coredump -p 99` (no such task) and `coredump` (all tasks) behave the same
in both builds: each prints `Start coredump` / `Finish coredump`, the dumps
have the same number of lines and the leading lines are identical, with no
assertion or abort.
`./tools/checkpatch.sh -g master..HEAD`: all checks pass.
Not tested on hardware.
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