Re: Time stamp resolution

[Jason Pearce]

Thanks for this Tip Paul, sorry it took me a long time to get around to 
trying it.


This catch for me was that the rules for the generated source files were 
also generated! So in my system there are two Makefile fragments that 
get included.
tbdep.mak - Which contains rules to generate source files
vhdldep.mak - Which contains rules to compile all the source files (and 
should include the generated sources)

At the moment I can get this simple example working, but there is 
something going wrong with my full build.

tbdep.mak : Makefile
   echo "generated1 :" > tbdep.mak.fail
   echo "    touch generated1" >> tbdep.mak.fail
   echo >> tbdep.mak.fail
   echo "generated2 :" >> tbdep.mak.fail
   echo "    touch generated2" >> tbdep.mak.fail
   echo >> tbdep.mak.fail
   echo "GENERATED_VHDL := generated1 generated2" >> tbdep.mak.fail
   /bin/mv tbdep.mak.fail tbdep.mak

include tbdep.mak

vhdldep.mak : ${GENERATED_VHDL}
   echo "compile:" > vhdldep.mak.fail
   echo "    @echo Compiling ${GENERATED_VHDL}" >> vhdldep.mak.fail
   /bin/mv vhdldep.mak.fail vhdldep.mak

include vhdldep.mak

clobber:
   /bin/rm -rf vhdldep.mak tbdep.mak
   /bin/rm -rf generated1 generated2


When I run make compile, Make first builds its two fragment files. The 
first time it builds vhdldep.mak it is incomplete because the generated 
sources have not been created yet. But then it builds the generated 
sources and this does re-build vhdldep.mak correctly. I was a bit 
worried that it would not re-evaluate the ${GENERATED_VHDL} variable, 
but it does. In the end, this example works, the "compile" target runs 
and echos the names of the generated files.

Unfortunately in my full build vhdldep.mak is NOT being rebuilt a 2nd 
time. I can not figure out why at the moment, it must be something silly 
I am not spotting.

[/tmp]$ make compile
Makefile:12: tbdep.mak: No such file or directory
Makefile:20: vhdldep.mak: No such file or directory
echo "compile:" > vhdldep.mak.fail
echo "  @echo Compiling " >> vhdldep.mak.fail
/bin/mv vhdldep.mak.fail vhdldep.mak
echo "generated1 :" > tbdep.mak.fail
echo "  touch generated1" >> tbdep.mak.fail
echo >> tbdep.mak.fail
echo "generated2 :" >> tbdep.mak.fail
echo "  touch generated2" >> tbdep.mak.fail
echo >> tbdep.mak.fail
echo "GENERATED_VHDL := generated1 generated2" >> tbdep.mak.fail
/bin/mv tbdep.mak.fail tbdep.mak
touch generated1
touch generated2
echo "compile:" > vhdldep.mak.fail
echo "  @echo Compiling generated1 generated2" >> vhdldep.mak.fail
/bin/mv vhdldep.mak.fail vhdldep.mak
Compiling generated1 generated2


Paul D. Smith wrote:

> %% Jason Pearce <address@hidden> writes:
>
>  jp> VHDL_SOURCES    := $(wildcard *.vhd)
>
>  jp> vhdldep.mak : ${VHDL_SOURCES}
>  jp>     perl vhdldep.pl -t mak ${VHDL_SOURCES} > vhdldep.makfail
>  jp> #    sleep 1
>  jp>     /bin/mv vhdldep.makfail vhdldep.mak
>
>  jp> include vhdldep.mak
>
>  jp> sources:: generated1.vhd
>
>  jp> generated1.vhd : generated1.vhd.m4
>  jp>     m4 generated1.vhd.m4 > generated1.vhd.fail
>  jp>     /bin/mv generated1.vhd.fail generated1.vhd
>   
>  jp> sources:: generated2.vhd
>
>  jp> generated2.vhd : generated1.vhd.m4
>  jp>     m4 generated2.vhd.m4 > generated2.vhd.fail
>  jp>     /bin/mv generated2.vhd.fail generated2.vhd
>
> Hm.  If I understand what you're doing, I would avoid this two-step
> operation by having the .mak file depend on the actual files.  Does
> something like this do what you want:
>
>
>  VHDL_SOURCES    := $(wildcard *.vhd)
>  vhdldep.mak : generated1.vhd generated2.vhd ${VHDL_SOURCES}
>        perl vhdldep.pl -t mak *.vhd > vhdldep.makfail
>        /bin/mv vhdldep.makfail vhdldep.mak
>
>  include vhdldep.mak
>
>
>  generated1.vhd : generated1.vhd.m4
>        m4 generated1.vhd.m4 > generated1.vhd.fail
>        /bin/mv generated1.vhd.fail generated1.vhd
>
>  generated2.vhd : generated1.vhd.m4
>        m4 generated2.vhd.m4 > generated2.vhd.fail
>        /bin/mv generated2.vhd.fail generated2.vhd
>
>
> ??  I think it should.
>
> Also, I would definitely use make variables for perl, m4, and /bin/mv
> rather than writing them out directly... :-).
>
>