This should significantly improve performance: on pokecrystal builds, perf
reported as much CPU time spent on `yyparse` as on `sym_UseNewMacroArgs`
Measurements show ~6 seconds of improvement on that codebase.
This also fixes#321, as a bonus, due to saner management!
The goal was to improve readability, but along the way a few things were
gained.
- Sorted sym and map files
- Infrastructure for supporting multiple .o versions
- Valgrind-proof, as far as my testing goes anyways
- Improved verbosity messages
- Added error checking
- Performance improvements, see end of commit message
The readability improvement was spurred while trying to make sense of the
old code while trying to implement features such as sorted sym and map
files.
I also did my best to remove hardcoded logic, such that modifications
should be doable; for example, "RAM loading" sections, which are linked
against a different location than the one they're stored at.
Some work remains to be done, see the "TODO:" and "FIXME:" comments.
Further, while regression tests pass, this new linker should be tested on
different codebases (ideally while instrumented with `make develop` and
under valgrind).
The few errors spotted in the man pages (alignment) need to be corrected.
Finally, documentation comments need to be written, I have written a lot of
them but not all.
This also provides a significant performance boost (benchmarked with a
51994-symbol project):
Current master RGBLINK:
2.02user 0.03system 0:02.06elapsed 99%CPU (0avgtext+0avgdata 84336maxresident)k
0inputs+11584outputs (0major+20729minor)pagefaults 0swaps
Rewritten RGBLINK:
0.19user 0.06system 0:00.63elapsed 40%CPU (0avgtext+0avgdata 32460maxresident)k
23784inputs+11576outputs (0major+7672minor)pagefaults 0swaps
Added define 'unused_' for '__attribute__((unused))'. The oldest version
of GCC with online docs (GCC 2.95.3, released in March 16, 2001 [1])
already has support for this attribute, so it doesn't make sense to
check the version.
Renamed 'noreturn' to 'noreturn_' for consistency.
[1] https://gcc.gnu.org/onlinedocs/
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
`__attribute__((noreturn))` has been supported since GCC 2.5, that was
released October 22, 1993. It doesn't make sense to check if the version
is at least that one, we are compiling for C99, that is more modern. [1]
Also, remove the MSVC check. This code is never compiled with it so
there may be problems that need to be solved to make it compile. All
releases cross-compiled from linux. If there is an actual need to
support MSVC, the compiler definitions can be added again.
Also, if the compiler is not supported, the compiler helpers default to
nothing, so the code can still compile.
[1] https://gcc.gnu.org/onlinedocs/
Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
