[LTP] [PATCH] cleanup: avoid to generate many redundant obj files

[Xiao Yang]

On 2/19/20 8:20 PM, Li Wang wrote:
> Hi Xiao,
>
>     Why don't you avoid libftest.o as well if you want to build test
>     by new rule?
>
>
> That should be generated because it is the local library. In LTP 
> Makefile, the sequencing is to build the library first then 
> compile&link to the testcase. We can avoid dumping the testname.o 
> since it only exists in the last phase.

Hi Li,

Thanks for your detailed explanation.

I think you try to change the building rule, as below:

Previous rule: generate all object files and then link them at the last 
phase.

---------------------------------------------

gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W 
-Wold-style-definition -D_FORTIFY_SOURCE=2 
-I/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-I../../../../include -I../../../../include -I../../../../include/old/  
-c -o swapoff01.o swapoff01.c
gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W 
-Wold-style-definition -D_FORTIFY_SOURCE=2 
-I/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-I../../../../include -I../../../../include -I../../../../include/old/  
-c -o ../swapon/libswapon.o ../swapon/libswapon.c
gcc   -L/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-L../../../../lib  swapoff01.o ../swapon/libswapon.o   -lltp -o swapoff01

---------------------------------------------

Current rule: just generate some common object files(e.g. library) and 
then mix building and link at the last phase.

---------------------------------------------

gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W 
-Wold-style-definition -D_FORTIFY_SOURCE=2 
-I/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-I../../../../include -I../../../../include -I../../../../include/old/  
-c -o ../swapon/libswapon.o ../swapon/libswapon.c
gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W 
-Wold-style-definition -D_FORTIFY_SOURCE=2 
-I/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-I../../../../include -I../../../../include -I../../../../include/old/ 
-L/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-L../../../../lib  swapoff01.c ../swapon/libswapon.o   -lltp -o swapoff01

---------------------------------------------

Why don't you remove all object files and mix building and link at the 
last phase?

---------------------------------------------

gcc -g -O2 -g -O2 -fno-strict-aliasing -pipe -Wall -W 
-Wold-style-definition -D_FORTIFY_SOURCE=2 
-I/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-I../../../../include -I../../../../include -I../../../../include/old/ 
-L/root/ltp/testcases/kernel/syscalls/swapoff/../swapon/ 
-L../../../../lib  swapoff01.c ../swapon/libswapon.c   -lltp -o swapoff01

---------------------------------------------

>
> And, I don't want to change too much for LTP build rule(I think it 
> works correctly), especially in the case directory some of the local 
> libraries are reused.  e.g The swapoff test needs linking to 
> ../swapon/libswapon.o, that requires libswapon.o is in the correct path.

You can build and link libswapon.c directly, as below:

---------------------------------

# grep MAKE_TARGETS Makefile
$(MAKE_TARGETS): %: ../swapon/libswapon.c

---------------------------------

Sorry, I am not sure if your improvement is the best way.

Thanks,

Xiao Yang

>
> Or, did I misunderstand your words? if yes, please correct me.
>
> -- 
> Regards,
> Li Wang
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