Commit 2404c0db authored by Thomas Petazzoni's avatar Thomas Petazzoni Committed by Peter Korsgaard
Browse files

graph-depends: remove redundant dependencies 



When doing a full graph of the dependencies, graph-depends starts by
doing a "make show-targets", which lists all the packages registered
in the $(TARGETS) variable. This variable contains all packages that
are enabled according to the .config file. Then, for each of those
packages, we used to create a "all" -> "package" dependency, even if
in fact most of some packages are already dependencies of other
packages. This creates a needlessly complex dependency graph.

This patch modifies graph-depends so that it filters out the unneeded
"all" -> "package" dependencies when "package" is already the
dependency of another package.

For example, if you have a configuration with libpng (which selects
zlib), "make show-targets" displays "libpng zlib", so graph-depends
used to create the following dependencies: (all -> libpng, all ->
zlib, libpng -> zlib). However, the (all -> zlib) dependency is not
really needed, as zlib is already the dependency of libpng. Those
dependencies are now filtered out.

Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: default avatarPeter Korsgaard <jacmet@sunsite.dk>
parent 7155fb7d

support/scripts/graph-depends

+33 −0
Original line number Diff line number Diff line
@@ -119,6 +119,37 @@ def get_all_depends(pkg): 
def pkg_node_name(pkg):

    return pkg.replace("-","")



# Helper function for remove_redundant_deps(). This function tells

# whether package "pkg" is the dependency of another package that is

# not the special "all" package.

def has_redundant_deps(deps, pkg):

    for dep in deps:

        if dep[0] != "all" and dep[1] == pkg:

            return True

    return False



# This function removes redundant dependencies of the special "all"

# package. This "all" package is created to reflect the origin of the

# selection for all packages that are not themselves selected by any

# other package. So for example if you enable libpng, zlib is enabled

# as a dependency. But zlib being selected by libpng, it also appears

# as a dependency of the "all" package. This needlessly complicates

# the generated dependency graph. So when we have the dependency list

# (all -> zlib, all -> libpn, libpng -> zlib), we get rid of the 'all

# -> zlib' dependency, because zlib is already a dependency of a

# regular package.

def remove_redundant_deps(deps):

    newdeps = []

    for dep in deps:

        if dep[0] != "all":

            newdeps.append(dep)

            continue

        if not has_redundant_deps(deps, dep[1]):

            newdeps.append(dep)

            continue

        sys.stderr.write("Removing redundant dep all -> %s\n" % dep[1])

    return newdeps



# In full mode, start with the result of get_targets() to get the main

# targets and then use get_all_depends() for each individual target.

if mode == FULL_MODE:
@@ -144,6 +175,8 @@ if mode == FULL_MODE: 
elif mode == PKG_MODE:

    dependencies = get_all_depends(rootpkg)



dependencies = remove_redundant_deps(dependencies)



# Start printing the graph data

print "digraph G {"