core/graph-depends: add option to graph reverse dependencies

Now that we can dump the reverse dependencies of a package, add the
ability to graph those.

It does not make sense to do a full reverse graph, as it would be
semantically equivalent to the direct graph. So we only provide a
per-package reverse graph.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Makefile

@@ -761,7 +761,7 @@ graph-depends: graph-depends-requirements
 	@$(INSTALL) -d $(GRAPHS_DIR)
 	@cd "$(CONFIG_DIR)"; \
 	$(TOPDIR)/support/scripts/graph-depends $(BR2_GRAPH_DEPS_OPTS) \
-		-o $(GRAPHS_DIR)/$(@).dot
+		--direct -o $(GRAPHS_DIR)/$(@).dot
 	dot $(BR2_GRAPH_DOT_OPTS) -T$(BR_GRAPH_OUT) \
 		-o $(GRAPHS_DIR)/$(@).$(BR_GRAPH_OUT) \
 		$(GRAPHS_DIR)/$(@).dot
@@ -977,6 +977,7 @@ help:
 	@echo '  <pkg>-show-depends     - List packages on which <pkg> depends'
 	@echo '  <pkg>-show-rdepends    - List packages which have <pkg> as a dependency'
 	@echo '  <pkg>-graph-depends    - Generate a graph of <pkg>'\''s dependencies'
+	@echo '  <pkg>-graph-rdepends   - Generate a graph of <pkg>'\''s reverse dependencies'
 	@echo '  <pkg>-dirclean         - Remove <pkg> build directory'
 	@echo '  <pkg>-reconfigure      - Restart the build from the configure step'
 	@echo '  <pkg>-rebuild          - Restart the build from the build step'

package/pkg-generic.mk

@@ -317,6 +317,16 @@ be selected at a time. Please fix your configuration)
 endif
 endef
 
+define pkg-graph-depends
+	@$$(INSTALL) -d $$(GRAPHS_DIR)
+	@cd "$$(CONFIG_DIR)"; \
+	$$(TOPDIR)/support/scripts/graph-depends $$(BR2_GRAPH_DEPS_OPTS) \
+		-p $(1) $(2) -o $$(GRAPHS_DIR)/$$(@).dot
+	dot $$(BR2_GRAPH_DOT_OPTS) -T$$(BR_GRAPH_OUT) \
+		-o $$(GRAPHS_DIR)/$$(@).$$(BR_GRAPH_OUT) \
+		$$(GRAPHS_DIR)/$$(@).dot
+endef
+
 ################################################################################
 # inner-generic-package -- generates the make targets needed to build a
 # generic package
@@ -702,13 +712,10 @@ $(1)-show-rdepends:
 			@echo $$($(2)_RDEPENDENCIES)
 
 $(1)-graph-depends: graph-depends-requirements
-			@$$(INSTALL) -d $$(GRAPHS_DIR)
-			@cd "$$(CONFIG_DIR)"; \
-			$$(TOPDIR)/support/scripts/graph-depends $$(BR2_GRAPH_DEPS_OPTS) \
-				-p $(1) -o $$(GRAPHS_DIR)/$$(@).dot
-			dot $$(BR2_GRAPH_DOT_OPTS) -T$$(BR_GRAPH_OUT) \
-				-o $$(GRAPHS_DIR)/$$(@).$$(BR_GRAPH_OUT) \
-				$$(GRAPHS_DIR)/$$(@).dot
+	$(call pkg-graph-depends,$(1),--direct)
+
+$(1)-graph-rdepends: graph-depends-requirements
+	$(call pkg-graph-depends,$(1),--reverse)
 
 $(1)-all-source:	$(1)-source
 $(1)-all-source:	$$(foreach p,$$($(2)_FINAL_ALL_DEPENDENCIES),$$(p)-all-source)

support/scripts/graph-depends

@@ -63,6 +63,10 @@ parser.add_argument("--transitive", dest="transitive", action='store_true',
                     default=False)
 parser.add_argument("--no-transitive", dest="transitive", action='store_false',
                     help="Draw (do not draw) transitive dependencies")
+parser.add_argument("--direct", dest="direct", action='store_true', default=True,
+                    help="Draw direct dependencies (the default)")
+parser.add_argument("--reverse", dest="direct", action='store_false',
+                    help="Draw reverse dependencies")
 args = parser.parse_args()
 
 check_only = args.check_only
@@ -95,6 +99,16 @@ else:
 
 transitive = args.transitive
 
+if args.direct:
+    rule = "show-depends"
+    arrow_dir = "forward"
+else:
+    if mode == MODE_FULL:
+        sys.stderr.write("--reverse needs a package\n")
+        sys.exit(1)
+    rule = "show-rdepends"
+    arrow_dir = "back"
+
 # Get the colours: we need exactly three colours,
 # so no need not split more than 4
 # We'll let 'dot' validate the colours...
@@ -151,7 +165,7 @@ def get_depends(pkgs):
     sys.stderr.write("Getting dependencies for %s\n" % pkgs)
     cmd = ["make", "-s", "--no-print-directory" ]
     for pkg in pkgs:
-        cmd.append("%s-show-depends" % pkg)
+        cmd.append("%s-%s" % (pkg, rule))
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE, universal_newlines=True)
     output = p.communicate()[0]
     if p.returncode != 0:
@@ -418,7 +432,7 @@ def print_pkg_deps(depth, pkg):
                     add = False
                     break
             if add:
-                outfile.write("%s -> %s\n" % (pkg_node_name(pkg), pkg_node_name(d)))
+                outfile.write("%s -> %s [dir=%s]\n" % (pkg_node_name(pkg), pkg_node_name(d), arrow_dir))
                 print_pkg_deps(depth+1, d)
 
 # Start printing the graph data