Build options for selecting a set of modules from jerry-ext

[glistening]

Currently nuttx-stm32f4 port uses only handler module from jerry-ext. (#1816)
tizenrt-artik05x port also want to use only handler.
However, it seems there is no cmake and build.py option.
I have no choice but including all jerry-ext modules, or not.

If so, I want to add build interfaces for both of cmake and build.py for selecting a set of modules from jerry-ext.

For build.py, what about using comma separated string? ( e.g., jerry-ext=arg,handler )
I don't want to introduce another parameter name. We may use same parameter name ( jerry-ext), and provides arg,handler as default value in order to respect history and other ports.

For cmake, I'd like to use jerryscript cmakefile convention for selecting a set of values. Could anyone give a suggestion? I can't find example in jerryscript cmakefiles.

[LaszloLango]

What's the problem with the arg build? Does jerry-ext build fail on artik05x target?

[glistening]

@LaszloLango

What's the problem with the arg build?

The problem is that we don't want to increase binary size for not-used jerryx modules. I reduced binary size about 1.1KB on NuttX with #1816 by removing arg module that is not used in nuttx-stm32f4 port.

Does jerry-ext build fail on artik05x target?

Yes. jerry-ext build fails on artik05x target. I might fix the error if I investigate the error. However, my priority at this moment is building small binary by selecting jerry extension modules without changing jerry-ext/CMakelists.txt manually.

[glistening]

@LaszloLango I fixed jerry-ext build error in #1906.

[LaszloLango]

The problem is that we don't want to increase binary size for not-used jerryx modules. I reduced binary size about 1.1KB on NuttX with #1816 by removing arg module that is not used in nuttx-stm32f4 port.

This is odd. The linker should drop the unused functions. AFAIK, the compilation of 'arg' must not increase the binary size if you don't use it.

[martijnthe]

@glistening could you check the .map file to see what part of the arg module exactly is causing the 1.1KB increase when not using it?

[glistening]

@LaszloLango, @martijnthe For nuttx-stm32f4 port, we generate all-in-one C file. Does linker drop the unused function in all-in-one source? To make sure, I will check it again. And for tizenrt-artik05x port, we currently don't use all-in-one source, I think you're right. I will check the binary size since I fixed the build error (#1906). Thank you.

[glistening]

Here is the result from nuttx-stm32f4 port. (all-in-one)

jerry-ext/handler/*

$ make
...
find ../../../jerryscript/jerry-ext/handler -name "*.c" | sed -r -e 's/(\.\.\/)*(.+)/#include "\2"/g' > jerry_ext_allin.c
CC:  jerry_ext_allin.c
...
$ ls -al nuttx.bin
-rwxrwxr-x 1 brian brian 241404 Jul  5 08:03 nuttx.bin

jerry-ext/*

$ make
...
find ../../../jerryscript/jerry-ext -name "*.c" | sed -r -e 's/(\.\.\/)*(.+)/#include "\2"/g' > jerry_ext_allin.c
CC:  jerry_ext_allin.c
...
$ ls -al nuttx.bin 
-rwxrwxr-x 1 brian brian 244384 Jul  5 08:06 nuttx.bin

[glistening]

I think we can close this issue. I was confused with the all-in-one case. We don't need to specify explicitly for generating archive fie since the linker will drop the unused object file automatically.