From 9d7c1a2a180ab153a54809133fa7080f8213b44a Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Tue, 11 Oct 2011 19:27:55 +0000
Subject: [PATCH] Add support for viewing the module graph via Graphviz, for
 debugging purposes.

llvm-svn: 141697
---
 .../clang/Serialization/ModuleManager.h       |  3 ++
 clang/lib/Serialization/ModuleManager.cpp     | 49 +++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/clang/include/clang/Serialization/ModuleManager.h b/clang/include/clang/Serialization/ModuleManager.h
index 65a5d5e2ec20..f86915a79cd0 100644
--- a/clang/include/clang/Serialization/ModuleManager.h
+++ b/clang/include/clang/Serialization/ModuleManager.h
@@ -146,6 +146,9 @@ public:
   void visitDepthFirst(bool (*Visitor)(Module &M, bool Preorder, 
                                        void *UserData), 
                        void *UserData);
+  
+  /// \brief View the graphviz representation of the module graph.
+  void viewGraph();
 };
 
 } } // end namespace clang::serialization
diff --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index a9fe64d42bdb..c4b1f7199bed 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -16,6 +16,10 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/system_error.h"
 
+#ifndef NDEBUG
+#include "llvm/Support/GraphWriter.h"
+#endif
+
 using namespace clang;
 using namespace serialization;
 
@@ -202,3 +206,48 @@ void ModuleManager::visitDepthFirst(bool (*Visitor)(Module &M, bool Preorder,
       return;
   }
 }
+
+#ifndef NDEBUG
+namespace llvm {
+  template<>
+  struct GraphTraits<ModuleManager> {
+    typedef Module NodeType;
+    typedef llvm::SetVector<Module *>::const_iterator ChildIteratorType;
+    typedef ModuleManager::ModuleConstIterator nodes_iterator;
+    
+    static ChildIteratorType child_begin(NodeType *Node) {
+      return Node->Imports.begin();
+    }
+
+    static ChildIteratorType child_end(NodeType *Node) {
+      return Node->Imports.end();
+    }
+    
+    static nodes_iterator nodes_begin(const ModuleManager &Manager) {
+      return Manager.begin();
+    }
+    
+    static nodes_iterator nodes_end(const ModuleManager &Manager) {
+      return Manager.end();
+    }
+  };
+  
+  template<>
+  struct DOTGraphTraits<ModuleManager> : public DefaultDOTGraphTraits {
+    explicit DOTGraphTraits(bool IsSimple = false)
+      : DefaultDOTGraphTraits(IsSimple) { }
+    
+    static bool renderGraphFromBottomUp() {
+      return true;
+    }
+
+    std::string getNodeLabel(Module *M, const ModuleManager&) {
+      return llvm::sys::path::stem(M->FileName);
+    }
+  };
+}
+
+void ModuleManager::viewGraph() {
+  llvm::ViewGraph(*this, "Modules");
+}
+#endif