URL:
<https://savannah.gnu.org/bugs/?59318>
Summary: Add option ('-g') of generating build graph for
updated goals
Project: make
Submitted by: jonasdn
Submitted on: Thu 22 Oct 2020 08:00:08 AM UTC
Severity: 3 - Normal
Item Group: Enhancement
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Component Version: 4.3
Operating System: None
Fixed Release: None
Triage Status: None
_______________________________________________________
Details:
Hi!
I know this enhancement has been discussed before for the GNU Make project.
But I would like to modestly propose complementing the powerful
--print-database option with something that is a bit easier to grasp at a
glance.
A graph visualisation can be helpful in order to get a better understanding of
the workings of a GNU Make based project. Particularly if you are debugging
why something keeps rebuilding each pass or if you are very new to a projekt.
All the information that can be gleaned from this graph output is already
present in the output of --print-database. However I strive to present it more
succinct. Only the targets that were modified in the goal is present and the
relationship between targets and prerequisite is hopefully more clear.
The output from the goal graph is stored in files called _goal_.dot in the
starting directory.
The hope is also that this can be paired with already existing viewers and
explorers, since the dot language is well known (29 years!).
This is something that can be used for instance when trying to figure out why
something keeps rebuilding / updating on a second run of Make. Or for figuring
out the dependency chain of a particular goal. As a first approach to get a
hint, and then perhaps using --print-database to learn more.
An example (rebuilding GNU Make):
$ touch src/file.c
$ AM_MAKEFLAGS="-g" make -g
Making all in lib
make[1]: Entering directory '/home/jonas/sandbox/mymake/lib'
/home/jonas/sandbox/mymake/./make -g all-recursive
make[2]: Entering directory '/home/jonas/sandbox/mymake/lib'
make[3]: Entering directory '/home/jonas/sandbox/mymake/lib'
make[3]: Nothing to be done for 'all-am'.
make[3]: Leaving directory '/home/jonas/sandbox/mymake/lib'
make[2]: Writing dependency graph to
'/home/jonas/sandbox/mymake/lib/all-recursive.dot'
make[2]: Leaving directory '/home/jonas/sandbox/mymake/lib'
make[1]: Writing dependency graph to
'/home/jonas/sandbox/mymake/lib/all.dot'
make[1]: Leaving directory '/home/jonas/sandbox/mymake/lib'
Making all in po
make[1]: Entering directory '/home/jonas/sandbox/mymake/po'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/jonas/sandbox/mymake/po'
Making all in doc
make[1]: Entering directory '/home/jonas/sandbox/mymake/doc'
make[1]: Nothing to be done for 'all'.
make[1]: Leaving directory '/home/jonas/sandbox/mymake/doc'
make[1]: Entering directory '/home/jonas/sandbox/mymake'
[...]
[gcc building]
[...]
make[1]: Writing dependency graph to
'/home/jonas/sandbox/mymake/all-am.dot'
make[1]: Leaving directory '/home/jonas/sandbox/mymake'
make: Writing dependency graph to '/home/jonas/sandbox/mymake/all.dot'
$ cat all-am.dot
digraph all-am {
"make" -> "src/file.o"
"all-am" -> "make"
"all-am"
}
$ cat all.dot
digraph all {
"all" -> "all-recursive" [label="forced: PHONY prerequisite"]
"all"
}
PNG versions of these graphs (generated with dot -Tpng) can be found as
attachments.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Thu 22 Oct 2020 08:00:08 AM UTC Name:
0001-Add-g-opt-for-graph-output-of-modified-targets.patch Size: 9KiB By:
jonasdn
<http://savannah.gnu.org/bugs/download.php?file_id=50045>
-------------------------------------------------------
Date: Thu 22 Oct 2020 08:00:08 AM UTC Name: all.png Size: 12KiB By:
jonasdn
<http://savannah.gnu.org/bugs/download.php?file_id=50046>
-------------------------------------------------------
Date: Thu 22 Oct 2020 08:00:08 AM UTC Name: all-am.png Size: 11KiB By:
jonasdn
<http://savannah.gnu.org/bugs/download.php?file_id=50047>
_______________________________________________________
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