Started as a project to help debugging makefiles marshaling non trivial bioinformatics pipelines in the mid 2000's, did its job and was promptly forgotten. Resurrected spring 2014 in a more open environment and released into the wild.

Create a graphical representation of a makefile targets and their dependencies.

• errr ... practically none ("We don't need no steenking requirements")
• Pretty much any *nix based system or other OS with make & awk ported.
• And any tool to view or convert GraphViz's dot format files into an image.

• Evidence you are doing what you intend without lapses or redundancy.
• Figuring out what someone else (or previous self) was thinking.
• Live Documentation

• convert the Makefile into a partially ordered set.
• convert a partial ordered set into the dot directed graph format
• generate an image of the dot file

include introspect.makefile in your makefile
(or another file included by your makefile)
adjust paths to dot and the awk scripts if necessary,
then issue

    make introspect  

you can also invoke the introspect_clean target to delete the files created.

Call the awk scripts yourself on the command line
without needing to include anything in the makefile.
something like:

   makefile2po.awk yourmakefile | potodot.awk -v "TAG=graphname" | dot -Tpng -o graphname.png

This gives an easy opportunity to filter out or modify labels before the pipe to potodot.awk

ex:

    makefile2po.awk yourmakefile | grep -vE "PHONY|clean" | potodot.awk ...

to keep housekeeping nodes & edges from cluttering up the graph.

Other uses include topologically sorting the makefile labels to help find critical paths

   makefile2po.awk yourmakefile | tsort

Or use potodot.awk to turn any reasonable list of pairs into a graph!

(where reasonable is defined by what the GraphViz dot format accepts as node labels)

Designed to take the fairly straightforward makefiles I tend to generate building data processing workflows and reduce them to a simplified 'adjacency list' aka 'partially ordered set'.

Currently excluding nodes not participating in an edge but I may revisit that.

Depending on how you want to look at it

• root nodes are displayed as rectangular boxes
• interior nodes are ovals
• leaf nodes are bolded ovals
• dependency arrows point to targets that required them

It is just using pattern matching, not full on parsing of makefiles.
So it will not understand suffix rules, conditionals or looping etc.

It will remove all the decorations (non alphanumeric and underscore)
from the labels so your labels should not only differ by decoration if that is important.
i.e. nodes that are not the same being collapsed together.