Hello Thomas, Thomas Martitz <ku...@rockbox.org> writes:
> Am 07.03.2017 um 18:44 schrieb Mathieu Lirzin: > >> Sorry, but I am still not convinced. While I agree it is only a small >> change regarding the amount of code, this new option has to be >> documented and maintained. Beyond optimizing the support of recursive >> and non-recursive makefiles providing the same targets which is a hack >> that can't reasonably be documented in Automake manual, I can't find a >> reason to justify its presence. > > Alright, this makes me bitter, since I'm trying to get feedback on > this for more than a year, and the previous indications seemed like > the change would be OK (e.g. [1]) I fully understand how you can feel. > Let me try to come from a different direction and completely ignore my > use case. Even for normal, non-recursive use, Automake generates > unwieldy long file names. Consider this: > > $ cat root/Makefile.am: > AUTOMAKE_OPTIONS = subdir-objects > include > projects/fancy_product/lib/config_parser/test/regression_tests/Makefile.inc > > $ cat > root/projects/fancy_product/lib/config_parser/test/regression_tests/Makefile.inc > > bin_PROGRAMS = helper > helper_SOURCES = %D%/helper.c > helper_CFLAGS = $(AM_CFLAGS) > > > Running make generates: > root/projects/fancy_product/lib/config_parser/test/regression_tests/projects_fancy_product_lib_config_parser_test_regression_tests_helper-helper.o > > This is completely unnecessary, as there is no chance that objects > overwrite each other (due to subdir-objects, this is a problem with > non-subdir-objects, if different subdirs have source files with the > same name). It can also create real problems, which is why _SHORTNAME > exists at all. > > It would be far more useful if objects would generally have shorter > file names under subdir-objects, > i.e. > root/projects/fancy_product/lib/config_parser/test/regression_tests/helper-helper.o > (helper- prefix due to target specific CFLAGS). > > So if it's a problem to support this as an option, then I would like > to ask to simply switch the generated file names unconditionally when > subdir-objects is enabled (this was already suggested in [1]). I was > afraid of changing any existing behavior, this is why I decided for a > new opt-in behavior. But I don't think the object file names are > documented such that they are not allowed to change. I would like to > prepare that change if it's OK for you. I have never considered that possibility. :) I have blindy supposed that there was a good reason for such long names even with the 'subdir-objects' option on. However intuitively I don't see any potential issue, so unless I overlook something, I think such change would be acceptable. When I have some time, I will make some research in the mailing list archives and in the git logs about potential known issues with this approach. I will let you know if I found any. >> Having said that I would happily accept a patch that fixes the usage of >> %C%, %D% in _SHORTNAME, which beyond the inconvenience of having to >> define it for each program or library, would achieve your goal of not >> compiling some files twice when invoking make in different locations. >> > > This is truly very hard, maybe impossible. I have looked into it > [1]. The core issue is that _SHORTNAME, unlike all other variables, is > already evaluated when generating Makefile.in., as the make targets > are already completed. Automake conditionals can only comment out > lines in the Makefile, they cannot make complex changes like renaming > make targets or dependencies or process recipes. > > It would be a major change, if possible at all, under the current > architecture of Automake. OK, thanks for investigating this. -- Mathieu Lirzin GPG: F2A3 8D7E EB2B 6640 5761 070D 0ADE E100 9460 4D37
