Feature proposal: sort file compilation order by time

[David Sterba]

Hi,

I'd like to present an idea which can make edit-compile-edit
cycle faster.

The idea is simple: compile first files which vere modified
most recently.

Makefile.am hold fixed list of _SOURCES for each target.
Order of files can be changed, of course, but this needs
regeneration of Makefile and this should not be done on every
compilation.

Instead, there should exist a Makefile target for each bin/lib,
called eg. <target>-build-order, which scans <target>_SOURCES
in current directory, sorts by time and creates a file (<target)-build-order)
which will be included in Makefile. This file overrides a variable
which holds built object files for <target>. By default, Makefile
has predefined orded, given by <target>_SOURCES.

By building recently touched files first, I do not have to wait for
compilation of untouched objects. This is significant for C++ sources,
since these may take long time to compile.


This feature is useful only for development building, not for
final, so it can use the .deps/ directory for storing target-order
files.

See attached files for example.


Well, I'd like to ask now, if this idea can be icluded in automake
(with proper implementation) ?


Please CC: me, I'm not on the list.

bye
Dave

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