Index: cfe/trunk/test/Analysis/exploded-graph-rewriter/explorers.dot
===================================================================
--- cfe/trunk/test/Analysis/exploded-graph-rewriter/explorers.dot
+++ cfe/trunk/test/Analysis/exploded-graph-rewriter/explorers.dot
@@ -1,37 +0,0 @@
-// RUN: %exploded_graph_rewriter %s \
-// RUN:     | FileCheck %s -check-prefixes=CHECK,BASIC
-// RUN: %exploded_graph_rewriter -s %s \
-// RUN:     | FileCheck %s -check-prefixes=CHECK,SINGLE
-
-// FIXME: Substitution doesn't seem to work on Windows.
-// UNSUPPORTED: system-windows
-
-Node0x1 [shape=record,label=
- "{{ "node_id": 1, "pointer": "0x1", "has_report": false, "is_sink": false,
-      "program_state": null, "program_points": []}\l}"];
-
-Node0x2 [shape=record,label=
- "{{ "node_id": 2, "pointer": "0x2", "has_report": false, "is_sink": false,
-      "program_state": null, "program_points": []}\l}"];
-
-Node0x3 [shape=record,label=
- "{{ "node_id": 3, "pointer": "0x3", "has_report": false, "is_sink": false,
-      "program_state": null, "program_points": []}\l}"];
-
-Node0x4 [shape=record,label=
- "{{ "node_id": 4, "pointer": "0x4", "has_report": false, "is_sink": false,
-      "program_state": null, "program_points": []}\l}"];
-
-// CHECK: Node0x1 -> Node0x2;
-Node0x1 -> Node0x2;
-
-// BASIC: Node0x1 -> Node0x3;
-// SINGLE-NOT: Node0x1 -> Node0x3;
-Node0x1 -> Node0x3;
-
-// CHECK: Node0x2 -> Node0x4;
-Node0x2 -> Node0x4;
-
-// BASIC: Node0x3 -> Node0x4;
-// SINGLE-NOT: Node0x3 -> Node0x4;
-Node0x3 -> Node0x4;
Index: cfe/trunk/test/Analysis/exploded-graph-rewriter/trimmers.dot
===================================================================
--- cfe/trunk/test/Analysis/exploded-graph-rewriter/trimmers.dot
+++ cfe/trunk/test/Analysis/exploded-graph-rewriter/trimmers.dot
@@ -0,0 +1,37 @@
+// RUN: %exploded_graph_rewriter %s \
+// RUN:     | FileCheck %s -check-prefixes=CHECK,BASIC
+// RUN: %exploded_graph_rewriter -s %s \
+// RUN:     | FileCheck %s -check-prefixes=CHECK,SINGLE
+
+// FIXME: Substitution doesn't seem to work on Windows.
+// UNSUPPORTED: system-windows
+
+Node0x1 [shape=record,label=
+ "{{ "node_id": 1, "pointer": "0x1", "has_report": false, "is_sink": false,
+      "program_state": null, "program_points": []}\l}"];
+
+Node0x2 [shape=record,label=
+ "{{ "node_id": 2, "pointer": "0x2", "has_report": false, "is_sink": false,
+      "program_state": null, "program_points": []}\l}"];
+
+Node0x3 [shape=record,label=
+ "{{ "node_id": 3, "pointer": "0x3", "has_report": false, "is_sink": false,
+      "program_state": null, "program_points": []}\l}"];
+
+Node0x4 [shape=record,label=
+ "{{ "node_id": 4, "pointer": "0x4", "has_report": false, "is_sink": false,
+      "program_state": null, "program_points": []}\l}"];
+
+// CHECK: Node0x1 -> Node0x2;
+Node0x1 -> Node0x2;
+
+// BASIC: Node0x1 -> Node0x3;
+// SINGLE-NOT: Node0x1 -> Node0x3;
+Node0x1 -> Node0x3;
+
+// CHECK: Node0x2 -> Node0x4;
+Node0x2 -> Node0x4;
+
+// BASIC: Node0x3 -> Node0x4;
+// SINGLE-NOT: Node0x3 -> Node0x4;
+Node0x3 -> Node0x4;
Index: cfe/trunk/utils/analyzer/exploded-graph-rewriter.py
===================================================================
--- cfe/trunk/utils/analyzer/exploded-graph-rewriter.py
+++ cfe/trunk/utils/analyzer/exploded-graph-rewriter.py
@@ -882,37 +882,36 @@
         visitor.visit_end_of_graph()
 
 
-# SinglePathExplorer traverses only a single path - the leftmost path
-# from the root. Useful when the trimmed graph is still too large
-# due to a large amount of equivalent reports.
-class SinglePathExplorer(object):
-    def __init__(self):
-        super(SinglePathExplorer, self).__init__()
+#===-----------------------------------------------------------------------===#
+# Trimmers cut out parts of the ExplodedGraph so that to focus on other parts.
+# Trimmers can be combined together by applying them sequentially.
+#===-----------------------------------------------------------------------===#
 
-    def explore(self, graph, visitor):
-        visitor.visit_begin_graph(graph)
 
-        # Keep track of visited nodes in order to avoid loops.
-        visited = set()
+# SinglePathTrimmer keeps only a single path - the leftmost path from the root.
+# Useful when the trimmed graph is still too large.
+class SinglePathTrimmer(object):
+    def __init__(self):
+        super(SinglePathTrimmer, self).__init__()
+
+    def trim(self, graph):
+        visited_nodes = set()
         node_id = graph.root_id
         while True:
-            visited.add(node_id)
+            visited_nodes.add(node_id)
             node = graph.nodes[node_id]
-            logging.debug('Visiting ' + node_id)
-            visitor.visit_node(node)
-            if len(node.successors) == 0:
-                break
-
-            succ_id = node.successors[0]
-            succ = graph.nodes[succ_id]
-            logging.debug('Visiting edge: %s -> %s ' % (node_id, succ_id))
-            visitor.visit_edge(node, succ)
-            if succ_id in visited:
+            if len(node.successors) > 0:
+                succ_id = node.successors[0]
+                succ = graph.nodes[succ_id]
+                node.successors = [succ_id]
+                succ.predecessors = [node_id]
+                if succ_id in visited_nodes:
+                    break
+                node_id = succ_id
+            else:
                 break
-
-            node_id = succ_id
-
-        visitor.visit_end_of_graph()
+        graph.nodes = {node_id: graph.nodes[node_id]
+                       for node_id in visited_nodes}
 
 
 #===-----------------------------------------------------------------------===#
@@ -960,10 +959,18 @@
             raw_line = raw_line.strip()
             graph.add_raw_line(raw_line)
 
-    explorer = SinglePathExplorer() if args.single_path else BasicExplorer()
+    trimmers = []
+    if args.single_path:
+        trimmers.append(SinglePathTrimmer())
+
+    explorer = BasicExplorer()
+
     visitor = DotDumpVisitor(args.diff, args.dark, args.gray, args.topology,
                              args.dump_dot_only)
 
+    for trimmer in trimmers:
+        trimmer.trim(graph)
+
     explorer.explore(graph, visitor)