13 files changed, 358 insertions, 255 deletions

diff --git a/Makefile.rules b/Makefile.rules
index a3a4937..44b8328 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -203,7 +203,6 @@ ifdef LLVMC_PLUGIN
 
 LIBRARYNAME := $(patsubst %,plugin_llvmc_%,$(LLVMC_PLUGIN))
 CPP.Flags += -DLLVMC_PLUGIN_NAME=$(LLVMC_PLUGIN)
-REQUIRES_EH := 1
 
 ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
   LD.Flags += -lCompilerDriver
@@ -226,8 +225,6 @@ ifdef LLVMC_BASED_DRIVER
 
 TOOLNAME = $(LLVMC_BASED_DRIVER)
 
-REQUIRES_EH := 1
-
 ifeq ($(ENABLE_LLVMC_DYNAMIC),1)
   LD.Flags += -lCompilerDriver
 else
diff --git a/include/llvm/CompilerDriver/Action.h b/include/llvm/CompilerDriver/Action.h
index 7014139..4ff6fd9 100644
--- a/include/llvm/CompilerDriver/Action.h
+++ b/include/llvm/CompilerDriver/Action.h
@@ -34,10 +34,14 @@ namespace llvmc {
     std::string OutFile_;
 
   public:
-    Action (const std::string& C, const StrVector& A,
-            bool S, const std::string& O)
-      : Command_(C), Args_(A), StopCompilation_(S), OutFile_(O)
-    {}
+    void Construct (const std::string& C, const StrVector& A,
+                    bool S, const std::string& O) {
+      Command_ = C;
+      Args_ = A;
+      StopCompilation_ = S;
+      OutFile_ = O;
+    }
+    bool IsConstructed () { return (Command_.size() != 0);}
 
     /// Execute - Executes the represented action.
     int Execute () const;
diff --git a/include/llvm/CompilerDriver/CompilationGraph.h b/include/llvm/CompilerDriver/CompilationGraph.h
index ba6ff47..9f2e50e 100644
--- a/include/llvm/CompilerDriver/CompilationGraph.h
+++ b/include/llvm/CompilerDriver/CompilationGraph.h
@@ -36,7 +36,7 @@ namespace llvmc {
   public:
 
     /// GetLanguage -  Find the language name corresponding to a given file.
-    const std::string& GetLanguage(const llvm::sys::Path&) const;
+    const std::string* GetLanguage(const llvm::sys::Path&) const;
   };
 
   /// Edge - Represents an edge of the compilation graph.
@@ -133,7 +133,7 @@ namespace llvmc {
 
     /// insertEdge - Insert a new edge into the graph. Takes ownership
     /// of the Edge object.
-    void insertEdge(const std::string& A, Edge* E);
+    int insertEdge(const std::string& A, Edge* E);
 
     /// Build - Build target(s) from the input file set. Command-line
     /// options are passed implicitly as global variables.
@@ -146,8 +146,8 @@ namespace llvmc {
 
     /// getNode - Return a reference to the node correponding to the
     /// given tool name. Throws std::runtime_error.
-    Node& getNode(const std::string& ToolName);
-    const Node& getNode(const std::string& ToolName) const;
+    Node* getNode(const std::string& ToolName);
+    const Node* getNode(const std::string& ToolName) const;
 
     /// viewGraph - This function is meant for use from the debugger.
     /// You can just say 'call G->viewGraph()' and a ghostview window
@@ -157,7 +157,7 @@ namespace llvmc {
     void viewGraph();
 
     /// writeGraph - Write Graphviz .dot source file to the current direcotry.
-    void writeGraph(const std::string& OutputFilename);
+    int writeGraph(const std::string& OutputFilename);
 
     // GraphTraits support.
     friend NodesIterator GraphBegin(CompilationGraph*);
@@ -169,14 +169,14 @@ namespace llvmc {
     /// getToolsVector - Return a reference to the list of tool names
     /// corresponding to the given language name. Throws
     /// std::runtime_error.
-    const tools_vector_type& getToolsVector(const std::string& LangName) const;
+    const tools_vector_type* getToolsVector(const std::string& LangName) const;
 
     /// PassThroughGraph - Pass the input file through the toolchain
     /// starting at StartNode.
-    void PassThroughGraph (const llvm::sys::Path& In, const Node* StartNode,
-                           const InputLanguagesSet& InLangs,
-                           const llvm::sys::Path& TempDir,
-                           const LanguageMap& LangMap) const;
+    int PassThroughGraph (const llvm::sys::Path& In, const Node* StartNode,
+                          const InputLanguagesSet& InLangs,
+                          const llvm::sys::Path& TempDir,
+                          const LanguageMap& LangMap) const;
 
     /// FindToolChain - Find head of the toolchain corresponding to
     /// the given file.
@@ -186,15 +186,15 @@ namespace llvmc {
                               const LanguageMap& LangMap) const;
 
     /// BuildInitial - Traverse the initial parts of the toolchains.
-    void BuildInitial(InputLanguagesSet& InLangs,
-                      const llvm::sys::Path& TempDir,
-                      const LanguageMap& LangMap);
+    int BuildInitial(InputLanguagesSet& InLangs,
+                     const llvm::sys::Path& TempDir,
+                     const LanguageMap& LangMap);
 
     /// TopologicalSort - Sort the nodes in topological order.
-    void TopologicalSort(std::vector<const Node*>& Out);
+    int TopologicalSort(std::vector<const Node*>& Out);
     /// TopologicalSortFilterJoinNodes - Call TopologicalSort and
     /// filter the resulting list to include only Join nodes.
-    void TopologicalSortFilterJoinNodes(std::vector<const Node*>& Out);
+    int TopologicalSortFilterJoinNodes(std::vector<const Node*>& Out);
 
     // Functions used to implement Check().
 
@@ -270,7 +270,7 @@ namespace llvmc {
     }
 
     inline pointer operator*() const {
-      return &OwningGraph->getNode((*EdgeIter)->ToolName());
+      return OwningGraph->getNode((*EdgeIter)->ToolName());
     }
     inline pointer operator->() const {
       return this->operator*();
@@ -301,7 +301,7 @@ namespace llvm {
     typedef llvmc::NodeChildIterator ChildIteratorType;
 
     static NodeType* getEntryNode(GraphType* G) {
-      return &G->getNode("root");
+      return G->getNode("root");
     }
 
     static ChildIteratorType child_begin(NodeType* N) {
diff --git a/include/llvm/CompilerDriver/Error.h b/include/llvm/CompilerDriver/Error.h
index fa678cf..0233929 100644
--- a/include/llvm/CompilerDriver/Error.h
+++ b/include/llvm/CompilerDriver/Error.h
@@ -7,29 +7,27 @@
 //
 //===----------------------------------------------------------------------===//
 //
-//  Exception classes for llvmc.
+//  Error handling.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_INCLUDE_COMPILER_DRIVER_ERROR_H
 #define LLVM_INCLUDE_COMPILER_DRIVER_ERROR_H
 
-#include <stdexcept>
+#include "llvm/Support/raw_ostream.h"
 
-namespace llvmc {
+#include <string>
 
-  /// error_code - This gets thrown during the compilation process if a tool
-  /// invocation returns a non-zero exit code.
-  class error_code: public std::runtime_error {
-    int Code_;
-  public:
-    error_code (int c)
-      : std::runtime_error("Tool returned error code"), Code_(c)
-    {}
+namespace llvmc {
 
-    int code() const { return Code_; }
-  };
+  inline void PrintError(const char* Err) {
+    extern const char* ProgramName;
+    llvm::errs() << ProgramName << ": " << Err << '\n';
+  }
 
+  inline void PrintError(const std::string& Err) {
+    PrintError(Err.c_str());
+  }
 }
 
 #endif // LLVM_INCLUDE_COMPILER_DRIVER_ERROR_H
diff --git a/include/llvm/CompilerDriver/Plugin.h b/include/llvm/CompilerDriver/Plugin.h
index e9a2048..75fd916 100644
--- a/include/llvm/CompilerDriver/Plugin.h
+++ b/include/llvm/CompilerDriver/Plugin.h
@@ -32,15 +32,15 @@ namespace llvmc {
     /// PreprocessOptions - The auto-generated function that performs various
     /// consistency checks on options (like ensuring that -O2 and -O3 are not
     /// used together).
-    virtual void PreprocessOptions() const = 0;
+    virtual int PreprocessOptions() const = 0;
 
     /// PopulateLanguageMap - The auto-generated function that fills in
     /// the language map (map from file extensions to language names).
-    virtual void PopulateLanguageMap(LanguageMap&) const = 0;
+    virtual int PopulateLanguageMap(LanguageMap&) const = 0;
 
     /// PopulateCompilationGraph - The auto-generated function that
     /// populates the compilation graph with nodes and edges.
-    virtual void PopulateCompilationGraph(CompilationGraph&) const = 0;
+    virtual int PopulateCompilationGraph(CompilationGraph&) const = 0;
 
     /// Needed to avoid a compiler warning.
     virtual ~BasePlugin() {}
@@ -68,7 +68,7 @@ namespace llvmc {
     /// RunInitialization - Calls PreprocessOptions, PopulateLanguageMap and
     /// PopulateCompilationGraph methods of all plugins. This populates the
     /// global language map and the compilation graph.
-    void RunInitialization(LanguageMap& langMap, CompilationGraph& graph) const;
+    int RunInitialization(LanguageMap& langMap, CompilationGraph& graph) const;
 
   private:
     // noncopyable
diff --git a/include/llvm/CompilerDriver/Tool.h b/include/llvm/CompilerDriver/Tool.h
index 85d1690..d064a03 100644
--- a/include/llvm/CompilerDriver/Tool.h
+++ b/include/llvm/CompilerDriver/Tool.h
@@ -38,17 +38,19 @@ namespace llvmc {
 
     virtual ~Tool() {}
 
-    virtual Action GenerateAction (const PathVector& inFiles,
-                                   bool  HasChildren,
-                                   const llvm::sys::Path& TempDir,
-                                   const InputLanguagesSet& InLangs,
-                                   const LanguageMap& LangMap) const = 0;
-
-    virtual Action GenerateAction (const llvm::sys::Path& inFile,
-                                   bool  HasChildren,
-                                   const llvm::sys::Path& TempDir,
-                                   const InputLanguagesSet& InLangs,
-                                   const LanguageMap& LangMap) const = 0;
+    virtual int GenerateAction (Action& Out,
+                                const PathVector& inFiles,
+                                const bool HasChildren,
+                                const llvm::sys::Path& TempDir,
+                                const InputLanguagesSet& InLangs,
+                                const LanguageMap& LangMap) const = 0;
+
+    virtual int GenerateAction (Action& Out,
+                                const llvm::sys::Path& inFile,
+                                const bool HasChildren,
+                                const llvm::sys::Path& TempDir,
+                                const InputLanguagesSet& InLangs,
+                                const LanguageMap& LangMap) const = 0;
 
     virtual const char*  Name() const = 0;
     virtual const char** InputLanguages() const = 0;
@@ -74,11 +76,13 @@ namespace llvmc {
     void ClearJoinList() { JoinList_.clear(); }
     bool JoinListEmpty() const { return JoinList_.empty(); }
 
-    Action GenerateAction(bool  HasChildren,
-                          const llvm::sys::Path& TempDir,
-                          const InputLanguagesSet& InLangs,
-                          const LanguageMap& LangMap) const {
-      return GenerateAction(JoinList_, HasChildren, TempDir, InLangs, LangMap);
+    int GenerateAction(Action& Out,
+                       const bool HasChildren,
+                       const llvm::sys::Path& TempDir,
+                       const InputLanguagesSet& InLangs,
+                       const LanguageMap& LangMap) const {
+      return GenerateAction(Out, JoinList_, HasChildren, TempDir, InLangs,
+                            LangMap);
     }
     // We shouldn't shadow base class's version of GenerateAction.
     using Tool::GenerateAction;
diff --git a/lib/CompilerDriver/Action.cpp b/lib/CompilerDriver/Action.cpp
index 5f30dce..0be8049 100644
--- a/lib/CompilerDriver/Action.cpp
+++ b/lib/CompilerDriver/Action.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/CompilerDriver/Action.h"
 #include "llvm/CompilerDriver/BuiltinOptions.h"
+#include "llvm/CompilerDriver/Error.h"
 
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/SystemUtils.h"
@@ -58,11 +59,15 @@ namespace {
 
     if (prog.isEmpty()) {
       prog = FindExecutable(name, ProgramName, (void *)(intptr_t)&Main);
-      if (prog.isEmpty())
-        throw std::runtime_error("Can't find program '" + name + "'");
+      if (prog.isEmpty()) {
+        PrintError("Can't find program '" + name + "'");
+        return -1;
+      }
+    }
+    if (!prog.canExecute()) {
+      PrintError("Program '" + name + "' is not executable.");
+      return -1;
     }
-    if (!prog.canExecute())
-      throw std::runtime_error("Program '" + name + "' is not executable.");
 
     // Build the command line vector and the redirects array.
     const sys::Path* redirects[3] = {0,0,0};
diff --git a/lib/CompilerDriver/CompilationGraph.cpp b/lib/CompilerDriver/CompilationGraph.cpp
index 7d1c7fe..4e953cb 100644
--- a/lib/CompilerDriver/CompilationGraph.cpp
+++ b/lib/CompilerDriver/CompilationGraph.cpp
@@ -25,21 +25,22 @@
 #include <iterator>
 #include <limits>
 #include <queue>
-#include <stdexcept>
 
 using namespace llvm;
 using namespace llvmc;
 
 namespace llvmc {
 
-  const std::string& LanguageMap::GetLanguage(const sys::Path& File) const {
+  const std::string* LanguageMap::GetLanguage(const sys::Path& File) const {
     StringRef suf = File.getSuffix();
     LanguageMap::const_iterator Lang =
       this->find(suf.empty() ? "*empty*" : suf);
-    if (Lang == this->end())
-      throw std::runtime_error("File '" + File.str() +
-                                "' has unknown suffix '" + suf.str() + '\'');
-    return Lang->second;
+    if (Lang == this->end()) {
+      PrintError("File '" + File.str() + "' has unknown suffix '"
+                 + suf.str() + '\'');
+      return 0;
+    }
+    return &Lang->second;
   }
 }
 
@@ -67,14 +68,16 @@ namespace {
       }
     }
 
-    if (!SingleMax)
-      throw std::runtime_error("Node " + NodeName +
-                               ": multiple maximal outward edges found!"
-                               " Most probably a specification error.");
-    if (!MaxEdge)
-      throw std::runtime_error("Node " + NodeName +
-                               ": no maximal outward edge found!"
-                               " Most probably a specification error.");
+    if (!SingleMax) {
+      PrintError("Node " + NodeName + ": multiple maximal outward edges found!"
+                 " Most probably a specification error.");
+      return 0;
+    }
+    if (!MaxEdge) {
+      PrintError("Node " + NodeName + ": no maximal outward edge found!"
+                 " Most probably a specification error.");
+      return 0;
+    }
     return MaxEdge;
   }
 
@@ -98,29 +101,34 @@ CompilationGraph::CompilationGraph() {
   NodesMap["root"] = Node(this);
 }
 
-Node& CompilationGraph::getNode(const std::string& ToolName) {
+Node* CompilationGraph::getNode(const std::string& ToolName) {
   nodes_map_type::iterator I = NodesMap.find(ToolName);
-  if (I == NodesMap.end())
-    throw std::runtime_error("Node " + ToolName + " is not in the graph");
-  return I->second;
+  if (I == NodesMap.end()) {
+    PrintError("Node " + ToolName + " is not in the graph");
+    return 0;
+  }
+  return &I->second;
 }
 
-const Node& CompilationGraph::getNode(const std::string& ToolName) const {
+const Node* CompilationGraph::getNode(const std::string& ToolName) const {
   nodes_map_type::const_iterator I = NodesMap.find(ToolName);
-  if (I == NodesMap.end())
-    throw std::runtime_error("Node " + ToolName + " is not in the graph!");
-  return I->second;
+  if (I == NodesMap.end()) {
+    PrintError("Node " + ToolName + " is not in the graph!");
+    return 0;
+  }
+  return &I->second;
 }
 
 // Find the tools list corresponding to the given language name.
-const CompilationGraph::tools_vector_type&
+const CompilationGraph::tools_vector_type*
 CompilationGraph::getToolsVector(const std::string& LangName) const
 {
   tools_map_type::const_iterator I = ToolsMap.find(LangName);
-  if (I == ToolsMap.end())
-    throw std::runtime_error("No tool corresponding to the language "
-                             + LangName + " found");
-  return I->second;
+  if (I == ToolsMap.end()) {
+    PrintError("No tool corresponding to the language " + LangName + " found");
+    return 0;
+  }
+  return &I->second;
 }
 
 void CompilationGraph::insertNode(Tool* V) {
@@ -128,29 +136,37 @@ void CompilationGraph::insertNode(Tool* V) {
     NodesMap[V->Name()] = Node(this, V);
 }
 
-void CompilationGraph::insertEdge(const std::string& A, Edge* Edg) {
-  Node& B = getNode(Edg->ToolName());
+int CompilationGraph::insertEdge(const std::string& A, Edge* Edg) {
+  Node* B = getNode(Edg->ToolName());
+  if (B == 0)
+    return -1;
+
   if (A == "root") {
-    const char** InLangs = B.ToolPtr->InputLanguages();
+    const char** InLangs = B->ToolPtr->InputLanguages();
     for (;*InLangs; ++InLangs)
       ToolsMap[*InLangs].push_back(IntrusiveRefCntPtr<Edge>(Edg));
     NodesMap["root"].AddEdge(Edg);
   }
   else {
-    Node& N = getNode(A);
-    N.AddEdge(Edg);
+    Node* N = getNode(A);
+    if (N == 0)
+      return -1;
+
+    N->AddEdge(Edg);
   }
   // Increase the inward edge counter.
-  B.IncrInEdges();
+  B->IncrInEdges();
+
+  return 0;
 }
 
 // Pass input file through the chain until we bump into a Join node or
 // a node that says that it is the last.
-void CompilationGraph::PassThroughGraph (const sys::Path& InFile,
-                                         const Node* StartNode,
-                                         const InputLanguagesSet& InLangs,
-                                         const sys::Path& TempDir,
-                                         const LanguageMap& LangMap) const {
+int CompilationGraph::PassThroughGraph (const sys::Path& InFile,
+                                        const Node* StartNode,
+                                        const InputLanguagesSet& InLangs,
+                                        const sys::Path& TempDir,
+                                        const LanguageMap& LangMap) const {
   sys::Path In = InFile;
   const Node* CurNode = StartNode;
 
@@ -158,25 +174,35 @@ void CompilationGraph::PassThroughGraph (const sys::Path& InFile,
     Tool* CurTool = CurNode->ToolPtr.getPtr();
 
     if (CurTool->IsJoin()) {
-      JoinTool& JT = dynamic_cast<JoinTool&>(*CurTool);
+      JoinTool& JT = static_cast<JoinTool&>(*CurTool);
       JT.AddToJoinList(In);
       break;
     }
 
-    Action CurAction = CurTool->GenerateAction(In, CurNode->HasChildren(),
-                                               TempDir, InLangs, LangMap);
+    Action CurAction;
+    if (int ret = CurTool->GenerateAction(CurAction, In, CurNode->HasChildren(),
+                                          TempDir, InLangs, LangMap)) {
+      return ret;
+    }
 
     if (int ret = CurAction.Execute())
-      throw error_code(ret);
+      return ret;
 
     if (CurAction.StopCompilation())
-      return;
+      return 0;
+
+    const Edge* Edg = ChooseEdge(CurNode->OutEdges, InLangs, CurNode->Name());
+    if (Edg == 0)
+      return -1;
+
+    CurNode = getNode(Edg->ToolName());
+    if (CurNode == 0)
+      return -1;
 
-    CurNode = &getNode(ChooseEdge(CurNode->OutEdges,
-                                  InLangs,
-                                  CurNode->Name())->ToolName());
     In = CurAction.OutFile();
   }
+
+  return 0;
 }
 
 // Find the head of the toolchain corresponding to the given file.
@@ -186,26 +212,39 @@ FindToolChain(const sys::Path& In, const std::string* ForceLanguage,
               InputLanguagesSet& InLangs, const LanguageMap& LangMap) const {
 
   // Determine the input language.
-  const std::string& InLanguage =
-    ForceLanguage ? *ForceLanguage : LangMap.GetLanguage(In);
+  const std::string* InLang = LangMap.GetLanguage(In);
+  if (InLang == 0)
+    return 0;
+  const std::string& InLanguage = (ForceLanguage ? *ForceLanguage : *InLang);
 
   // Add the current input language to the input language set.
   InLangs.insert(InLanguage);
 
   // Find the toolchain for the input language.
-  const tools_vector_type& TV = getToolsVector(InLanguage);
-  if (TV.empty())
-    throw std::runtime_error("No toolchain corresponding to language "
-                             + InLanguage + " found");
-  return &getNode(ChooseEdge(TV, InLangs)->ToolName());
+  const tools_vector_type* pTV = getToolsVector(InLanguage);
+  if (pTV == 0)
+    return 0;
+
+  const tools_vector_type& TV = *pTV;
+  if (TV.empty()) {
+    PrintError("No toolchain corresponding to language "
+               + InLanguage + " found");
+    return 0;
+  }
+
+  const Edge* Edg = ChooseEdge(TV, InLangs);
+  if (Edg == 0)
+    return 0;
+
+  return getNode(Edg->ToolName());
 }
 
 // Helper function used by Build().
 // Traverses initial portions of the toolchains (up to the first Join node).
 // This function is also responsible for handling the -x option.
-void CompilationGraph::BuildInitial (InputLanguagesSet& InLangs,
-                                     const sys::Path& TempDir,
-                                     const LanguageMap& LangMap) {
+int CompilationGraph::BuildInitial (InputLanguagesSet& InLangs,
+                                    const sys::Path& TempDir,
+                                    const LanguageMap& LangMap) {
   // This is related to -x option handling.
   cl::list<std::string>::const_iterator xIter = Languages.begin(),
     xBegin = xIter, xEnd = Languages.end();
@@ -255,15 +294,25 @@ void CompilationGraph::BuildInitial (InputLanguagesSet& InLangs,
 
     // Find the toolchain corresponding to this file.
     const Node* N = FindToolChain(In, xLanguage, InLangs, LangMap);
+    if (N == 0)
+      return -1;
     // Pass file through the chain starting at head.
-    PassThroughGraph(In, N, InLangs, TempDir, LangMap);
+    if (int ret = PassThroughGraph(In, N, InLangs, TempDir, LangMap))
+      return ret;
   }
+
+  return 0;
 }
 
 // Sort the nodes in topological order.
-void CompilationGraph::TopologicalSort(std::vector<const Node*>& Out) {
+int CompilationGraph::TopologicalSort(std::vector<const Node*>& Out) {
   std::queue<const Node*> Q;
-  Q.push(&getNode("root"));
+
+  Node* Root = getNode("root");
+  if (Root == 0)
+    return -1;
+
+  Q.push(Root);
 
   while (!Q.empty()) {
     const Node* A = Q.front();
@@ -271,12 +320,17 @@ void CompilationGraph::TopologicalSort(std::vector<const Node*>& Out) {
     Out.push_back(A);
     for (Node::const_iterator EB = A->EdgesBegin(), EE = A->EdgesEnd();
          EB != EE; ++EB) {
-      Node* B = &getNode((*EB)->ToolName());
+      Node* B = getNode((*EB)->ToolName());
+      if (B == 0)
+        return -1;
+
       B->DecrInEdges();
       if (B->HasNoInEdges())
         Q.push(B);
     }
   }
+
+  return 0;
 }
 
 namespace {
@@ -287,49 +341,64 @@ namespace {
 
 // Call TopologicalSort and filter the resulting list to include
 // only Join nodes.
-void CompilationGraph::
+int CompilationGraph::
 TopologicalSortFilterJoinNodes(std::vector<const Node*>& Out) {
   std::vector<const Node*> TopSorted;
-  TopologicalSort(TopSorted);
+  if (int ret = TopologicalSort(TopSorted))
+    return ret;
   std::remove_copy_if(TopSorted.begin(), TopSorted.end(),
                       std::back_inserter(Out), NotJoinNode);
+
+  return 0;
 }
 
 int CompilationGraph::Build (const sys::Path& TempDir,
                              const LanguageMap& LangMap) {
-
   InputLanguagesSet InLangs;
 
   // Traverse initial parts of the toolchains and fill in InLangs.
-  BuildInitial(InLangs, TempDir, LangMap);
+  if (int ret = BuildInitial(InLangs, TempDir, LangMap))
+    return ret;
 
   std::vector<const Node*> JTV;
-  TopologicalSortFilterJoinNodes(JTV);
+  if (int ret = TopologicalSortFilterJoinNodes(JTV))
+    return ret;
 
   // For all join nodes in topological order:
   for (std::vector<const Node*>::iterator B = JTV.begin(), E = JTV.end();
        B != E; ++B) {
 
     const Node* CurNode = *B;
-    JoinTool* JT = &dynamic_cast<JoinTool&>(*CurNode->ToolPtr.getPtr());
+    JoinTool* JT = &static_cast<JoinTool&>(*CurNode->ToolPtr.getPtr());
 
     // Are there any files in the join list?
     if (JT->JoinListEmpty() && !(JT->WorksOnEmpty() && InputFilenames.empty()))
       continue;
 
-    Action CurAction = JT->GenerateAction(CurNode->HasChildren(),
-                                          TempDir, InLangs, LangMap);
+    Action CurAction;
+    if (int ret = JT->GenerateAction(CurAction, CurNode->HasChildren(),
+                                     TempDir, InLangs, LangMap)) {
+      return ret;
+    }
 
     if (int ret = CurAction.Execute())
-      throw error_code(ret);
+      return ret;
 
     if (CurAction.StopCompilation())
       return 0;
 
-    const Node* NextNode = &getNode(ChooseEdge(CurNode->OutEdges, InLangs,
-                                               CurNode->Name())->ToolName());
-    PassThroughGraph(sys::Path(CurAction.OutFile()), NextNode,
-                     InLangs, TempDir, LangMap);
+    const Edge* Edg = ChooseEdge(CurNode->OutEdges, InLangs, CurNode->Name());
+    if (Edg == 0)
+      return -1;
+
+    const Node* NextNode = getNode(Edg->ToolName());
+    if (NextNode == 0)
+      return -1;
+
+    if (int ret = PassThroughGraph(sys::Path(CurAction.OutFile()), NextNode,
+                                   InLangs, TempDir, LangMap)) {
+      return ret;
+    }
   }
 
   return 0;
@@ -337,6 +406,7 @@ int CompilationGraph::Build (const sys::Path& TempDir,
 
 int CompilationGraph::CheckLanguageNames() const {
   int ret = 0;
+
   // Check that names for output and input languages on all edges do match.
   for (const_nodes_iterator B = this->NodesMap.begin(),
          E = this->NodesMap.end(); B != E; ++B) {
@@ -345,9 +415,11 @@ int CompilationGraph::CheckLanguageNames() const {
     if (N1.ToolPtr) {
       for (Node::const_iterator EB = N1.EdgesBegin(), EE = N1.EdgesEnd();
            EB != EE; ++EB) {
-        const Node& N2 = this->getNode((*EB)->ToolName());
+        const Node* N2 = this->getNode((*EB)->ToolName());
+        if (N2 == 0)
+          return -1;
 
-        if (!N2.ToolPtr) {
+        if (!N2->ToolPtr) {
           ++ret;
           errs() << "Error: there is an edge from '" << N1.ToolPtr->Name()
                  << "' back to the root!\n\n";
@@ -355,7 +427,7 @@ int CompilationGraph::CheckLanguageNames() const {
         }
 
         const char* OutLang = N1.ToolPtr->OutputLanguage();
-        const char** InLangs = N2.ToolPtr->InputLanguages();
+        const char** InLangs = N2->ToolPtr->InputLanguages();
         bool eq = false;
         for (;*InLangs; ++InLangs) {
           if (std::strcmp(OutLang, *InLangs) == 0) {
@@ -367,11 +439,11 @@ int CompilationGraph::CheckLanguageNames() const {
         if (!eq) {
           ++ret;
           errs() << "Error: Output->input language mismatch in the edge '"
-                 << N1.ToolPtr->Name() << "' -> '" << N2.ToolPtr->Name()
+                 << N1.ToolPtr->Name() << "' -> '" << N2->ToolPtr->Name()
                  << "'!\n"
                  << "Expected one of { ";
 
-          InLangs = N2.ToolPtr->InputLanguages();
+          InLangs = N2->ToolPtr->InputLanguages();
           for (;*InLangs; ++InLangs) {
             errs() << '\'' << *InLangs << (*(InLangs+1) ? "', " : "'");
           }
@@ -422,7 +494,12 @@ int CompilationGraph::CheckMultipleDefaultEdges() const {
 int CompilationGraph::CheckCycles() {
   unsigned deleted = 0;
   std::queue<Node*> Q;
-  Q.push(&getNode("root"));
+
+  Node* Root = getNode("root");
+  if (Root == 0)
+    return -1;
+
+  Q.push(Root);
 
   // Try to delete all nodes that have no ingoing edges, starting from the
   // root. If there are any nodes left after this operation, then we have a
@@ -434,7 +511,10 @@ int CompilationGraph::CheckCycles() {
 
     for (Node::iterator EB = A->EdgesBegin(), EE = A->EdgesEnd();
          EB != EE; ++EB) {
-      Node* B = &getNode((*EB)->ToolName());
+      Node* B = getNode((*EB)->ToolName());
+      if (B == 0)
+        return -1;
+
       B->DecrInEdges();
       if (B->HasNoInEdges())
         Q.push(B);
@@ -453,18 +533,28 @@ int CompilationGraph::CheckCycles() {
 
 int CompilationGraph::Check () {
   // We try to catch as many errors as we can in one go.
+  int errs = 0;
   int ret = 0;
 
   // Check that output/input language names match.
-  ret += this->CheckLanguageNames();
+  ret = this->CheckLanguageNames();
+  if (ret < 0)
+    return -1;
+  errs += ret;
 
   // Check for multiple default edges.
-  ret += this->CheckMultipleDefaultEdges();
+  ret = this->CheckMultipleDefaultEdges();
+  if (ret < 0)
+    return -1;
+  errs += ret;
 
   // Check for cycles.
-  ret += this->CheckCycles();
+  ret = this->CheckCycles();
+  if (ret < 0)
+    return -1;
+  errs += ret;
 
-  return ret;
+  return errs;
 }
 
 // Code related to graph visualization.
@@ -516,7 +606,7 @@ namespace llvm {
 
 }
 
-void CompilationGraph::writeGraph(const std::string& OutputFilename) {
+int CompilationGraph::writeGraph(const std::string& OutputFilename) {
   std::string ErrorInfo;
   raw_fd_ostream O(OutputFilename.c_str(), ErrorInfo);
 
@@ -526,9 +616,11 @@ void CompilationGraph::writeGraph(const std::string& OutputFilename) {
     errs() << "done.\n";
   }
   else {
-    throw std::runtime_error("Error opening file '" + OutputFilename
-                             + "' for writing!");
+    PrintError("Error opening file '" + OutputFilename + "' for writing!");
+    return -1;
   }
+
+  return 0;
 }
 
 void CompilationGraph::viewGraph() {
diff --git a/lib/CompilerDriver/Main.cpp b/lib/CompilerDriver/Main.cpp
index b5e507d..28b2737 100644
--- a/lib/CompilerDriver/Main.cpp
+++ b/lib/CompilerDriver/Main.cpp
@@ -20,7 +20,6 @@
 #include "llvm/System/Path.h"
 
 #include <sstream>
-#include <stdexcept>
 #include <string>
 
 namespace cl = llvm::cl;
@@ -31,9 +30,7 @@ namespace {
 
   std::stringstream* GlobalTimeLog;
 
-  sys::Path getTempDir() {
-    sys::Path tempDir;
-
+  int getTempDir(sys::Path& tempDir) {
     // The --temp-dir option.
     if (!TempDirname.empty()) {
       tempDir = TempDirname;
@@ -41,7 +38,7 @@ namespace {
     // GCC 4.5-style -save-temps handling.
     else if (SaveTemps == SaveTempsEnum::Unset) {
       tempDir = sys::Path::GetTemporaryDirectory();
-      return tempDir;
+      return 0;
     }
     else if (SaveTemps == SaveTempsEnum::Obj && !OutputFilename.empty()) {
       tempDir = OutputFilename;
@@ -49,35 +46,34 @@ namespace {
     }
     else {
       // SaveTemps == Cwd --> use current dir (leave tempDir empty).
-      return tempDir;
+      return 0;
     }
 
     if (!tempDir.exists()) {
       std::string ErrMsg;
-      if (tempDir.createDirectoryOnDisk(true, &ErrMsg))
-        throw std::runtime_error(ErrMsg);
+      if (tempDir.createDirectoryOnDisk(true, &ErrMsg)) {
+        PrintError(ErrMsg);
+        return -1;
+      }
     }
 
-    return tempDir;
+    return 0;
   }
 
   /// BuildTargets - A small wrapper for CompilationGraph::Build.
   int BuildTargets(CompilationGraph& graph, const LanguageMap& langMap) {
     int ret;
-    const sys::Path& tempDir = getTempDir();
+    sys::Path tempDir;
     bool toDelete = (SaveTemps == SaveTempsEnum::Unset);
 
-    try {
-      ret = graph.Build(tempDir, langMap);
-    }
-    catch(...) {
-      if (toDelete)
-        tempDir.eraseFromDisk(true);
-      throw;
-    }
+    if (int ret = getTempDir(tempDir))
+      return ret;
+
+    ret = graph.Build(tempDir, langMap);
 
     if (toDelete)
       tempDir.eraseFromDisk(true);
+
     return ret;
   }
 }
@@ -93,64 +89,54 @@ void AppendToGlobalTimeLog(const std::string& cmd, double time) {
 const char* ProgramName;
 
 int Main(int argc, char** argv) {
-  try {
-    LanguageMap langMap;
-    CompilationGraph graph;
-
-    ProgramName = argv[0];
+  int ret = 0;
+  LanguageMap langMap;
+  CompilationGraph graph;
 
-    cl::ParseCommandLineOptions
-      (argc, argv, "LLVM Compiler Driver (Work In Progress)",
-       /* ReadResponseFiles = */ false);
+  ProgramName = argv[0];
 
-    PluginLoader Plugins;
-    Plugins.RunInitialization(langMap, graph);
+  cl::ParseCommandLineOptions
+    (argc, argv, "LLVM Compiler Driver (Work In Progress)",
+     /* ReadResponseFiles = */ false);
 
-    if (CheckGraph) {
-      int ret = graph.Check();
-      if (!ret)
-        llvm::errs() << "check-graph: no errors found.\n";
+  PluginLoader Plugins;
+  if (int ret = Plugins.RunInitialization(langMap, graph))
+    return ret;
 
-      return ret;
-    }
+  if (CheckGraph) {
+    ret = graph.Check();
+    if (!ret)
+      llvm::errs() << "check-graph: no errors found.\n";
 
-    if (ViewGraph) {
-      graph.viewGraph();
-      if (!WriteGraph)
-        return 0;
-    }
+    return ret;
+  }
 
-    if (WriteGraph) {
-      graph.writeGraph(OutputFilename.empty()
-                       ? std::string("compilation-graph.dot")
-                       : OutputFilename);
+  if (ViewGraph) {
+    graph.viewGraph();
+    if (!WriteGraph)
       return 0;
-    }
+  }
 
-    if (Time) {
-      GlobalTimeLog = new std::stringstream;
-      GlobalTimeLog->precision(2);
-    }
+  if (WriteGraph) {
+    const std::string& Out = (OutputFilename.empty()
+                              ? std::string("compilation-graph.dot")
+                              : OutputFilename);
+    return graph.writeGraph(Out);
+  }
 
-    int ret = BuildTargets(graph, langMap);
+  if (Time) {
+    GlobalTimeLog = new std::stringstream;
+    GlobalTimeLog->precision(2);
+  }
 
-    if (Time) {
-      llvm::errs() << GlobalTimeLog->str();
-      delete GlobalTimeLog;
-    }
+  ret = BuildTargets(graph, langMap);
 
-    return ret;
-  }
-  catch(llvmc::error_code& ec) {
-    return ec.code();
+  if (Time) {
+    llvm::errs() << GlobalTimeLog->str();
+    delete GlobalTimeLog;
   }
-  catch(const std::exception& ex) {
-    llvm::errs() << argv[0] << ": " << ex.what() << '\n';
-  }
-  catch(...) {
-    llvm::errs() << argv[0] << ": unknown error!\n";
-  }
-  return 1;
+
+  return ret;
 }
 
 } // end namespace llvmc
diff --git a/lib/CompilerDriver/Makefile b/lib/CompilerDriver/Makefile
index 66c6d11..b829f52 100644
--- a/lib/CompilerDriver/Makefile
+++ b/lib/CompilerDriver/Makefile
@@ -21,9 +21,6 @@ else
   LINK_COMPONENTS = support system
 endif
 
-REQUIRES_EH := 1
-REQUIRES_RTTI := 1
-
 include $(LEVEL)/Makefile.common
 
 ifeq ($(ENABLE_LLVMC_DYNAMIC_PLUGINS), 1)
diff --git a/lib/CompilerDriver/Plugin.cpp b/lib/CompilerDriver/Plugin.cpp
index 0fdfef4..c06bda3 100644
--- a/lib/CompilerDriver/Plugin.cpp
+++ b/lib/CompilerDriver/Plugin.cpp
@@ -62,17 +62,22 @@ namespace llvmc {
     pluginListInitialized = false;
   }
 
-  void PluginLoader::RunInitialization(LanguageMap& langMap,
+  int PluginLoader::RunInitialization(LanguageMap& langMap,
                                        CompilationGraph& graph) const
   {
     llvm::sys::SmartScopedLock<true> Lock(*PluginMutex);
     for (PluginList::iterator B = Plugins.begin(), E = Plugins.end();
          B != E; ++B) {
       const BasePlugin* BP = *B;
-      BP->PreprocessOptions();
-      BP->PopulateLanguageMap(langMap);
-      BP->PopulateCompilationGraph(graph);
+      if (int ret = BP->PreprocessOptions())
+        return ret;
+      if (int ret = BP->PopulateLanguageMap(langMap))
+        return ret;
+      if (int ret = BP->PopulateCompilationGraph(graph))
+        return ret;
     }
+
+    return 0;
   }
 
 }
diff --git a/tools/llvmc/Makefile b/tools/llvmc/Makefile
index 8f99526..df91728 100644
--- a/tools/llvmc/Makefile
+++ b/tools/llvmc/Makefile
@@ -11,7 +11,6 @@ LEVEL = ../..
 
 export LLVMC_BASED_DRIVER_NAME = llvmc
 export LLVMC_BUILTIN_PLUGINS = Base Clang
-REQUIRES_RTTI = 1
 
 DIRS = plugins driver
 
diff --git a/utils/TableGen/LLVMCConfigurationEmitter.cpp b/utils/TableGen/LLVMCConfigurationEmitter.cpp
index 4a16930..be6e398 100644
--- a/utils/TableGen/LLVMCConfigurationEmitter.cpp
+++ b/utils/TableGen/LLVMCConfigurationEmitter.cpp
@@ -1957,10 +1957,10 @@ struct ActionHandlingCallbackBase
                   unsigned IndentLevel, raw_ostream& O) const
   {
     O.indent(IndentLevel)
-      << "throw std::runtime_error(\"" <<
-      (d.getNumArgs() >= 1 ? InitPtrToString(d.getArg(0))
-       : "Unknown error!")
+      << "PrintError(\""
+      << (d.getNumArgs() >= 1 ? InitPtrToString(d.getArg(0)) : "Unknown error!")
       << "\");\n";
+    O.indent(IndentLevel) << "return -1;\n";
   }
 
   void onWarningDag(const DagInit& d,
@@ -2154,25 +2154,32 @@ class EmitActionHandlersCallback :
 };
 
 void EmitGenerateActionMethodHeader(const ToolDescription& D,
-                                    bool IsJoin, raw_ostream& O)
+                                    bool IsJoin, bool Naked,
+                                    raw_ostream& O)
 {
+  O.indent(Indent1) << "int GenerateAction(Action& Out,\n";
+
   if (IsJoin)
-    O.indent(Indent1) << "Action GenerateAction(const PathVector& inFiles,\n";
+    O.indent(Indent2) << "const PathVector& inFiles,\n";
   else
-    O.indent(Indent1) << "Action GenerateAction(const sys::Path& inFile,\n";
+    O.indent(Indent2) << "const sys::Path& inFile,\n";
 
-  O.indent(Indent2) << "bool HasChildren,\n";
+  O.indent(Indent2) << "const bool HasChildren,\n";
   O.indent(Indent2) << "const llvm::sys::Path& TempDir,\n";
   O.indent(Indent2) << "const InputLanguagesSet& InLangs,\n";
   O.indent(Indent2) << "const LanguageMap& LangMap) const\n";
   O.indent(Indent1) << "{\n";
-  O.indent(Indent2) << "std::string cmd;\n";
-  O.indent(Indent2) << "std::string out_file;\n";
-  O.indent(Indent2) << "std::vector<std::pair<unsigned, std::string> > vec;\n";
-  O.indent(Indent2) << "bool stop_compilation = !HasChildren;\n";
-  O.indent(Indent2) << "bool no_out_file = false;\n";
-  O.indent(Indent2) << "const char* output_suffix = \""
-                    << D.OutputSuffix << "\";\n";
+
+  if (!Naked) {
+    O.indent(Indent2) << "std::string cmd;\n";
+    O.indent(Indent2) << "std::string out_file;\n";
+    O.indent(Indent2)
+      << "std::vector<std::pair<unsigned, std::string> > vec;\n";
+    O.indent(Indent2) << "bool stop_compilation = !HasChildren;\n";
+    O.indent(Indent2) << "bool no_out_file = false;\n";
+    O.indent(Indent2) << "const char* output_suffix = \""
+                      << D.OutputSuffix << "\";\n";
+  }
 }
 
 // EmitGenerateActionMethod - Emit either a normal or a "join" version of the
@@ -2181,7 +2188,7 @@ void EmitGenerateActionMethod (const ToolDescription& D,
                                const OptionDescriptions& OptDescs,
                                bool IsJoin, raw_ostream& O) {
 
-  EmitGenerateActionMethodHeader(D, IsJoin, O);
+  EmitGenerateActionMethodHeader(D, IsJoin, /* Naked = */ false, O);
 
   if (!D.CmdLine)
     throw "Tool " + D.Name + " has no cmd_line property!";
@@ -2245,8 +2252,9 @@ void EmitGenerateActionMethod (const ToolDescription& D,
     O.indent(Indent2) << "}\n";
   }
 
-  O.indent(Indent2) << "return Action(cmd, this->SortArgs(vec), "
+  O.indent(Indent2) << "Out.Construct(cmd, this->SortArgs(vec), "
                     << "stop_compilation, out_file);\n";
+  O.indent(Indent2) << "return 0;\n";
   O.indent(Indent1) << "}\n\n";
 }
 
@@ -2256,14 +2264,11 @@ void EmitGenerateActionMethods (const ToolDescription& ToolDesc,
                                 const OptionDescriptions& OptDescs,
                                 raw_ostream& O) {
   if (!ToolDesc.isJoin()) {
-    O.indent(Indent1) << "Action GenerateAction(const PathVector& inFiles,\n";
-    O.indent(Indent2) << "bool HasChildren,\n";
-    O.indent(Indent2) << "const llvm::sys::Path& TempDir,\n";
-    O.indent(Indent2) << "const InputLanguagesSet& InLangs,\n";
-    O.indent(Indent2) << "const LanguageMap& LangMap) const\n";
-    O.indent(Indent1) << "{\n";
-    O.indent(Indent2) << "throw std::runtime_error(\"" << ToolDesc.Name
+    EmitGenerateActionMethodHeader(ToolDesc, /* IsJoin = */ true,
+                                   /* Naked = */ true, O);
+    O.indent(Indent2) << "PrintError(\"" << ToolDesc.Name
                       << " is not a Join tool!\");\n";
+    O.indent(Indent2) << "return -1;\n";
     O.indent(Indent1) << "}\n\n";
   }
   else {
@@ -2627,7 +2632,7 @@ public:
 void EmitPreprocessOptions (const RecordKeeper& Records,
                             const OptionDescriptions& OptDecs, raw_ostream& O)
 {
-  O << "void PreprocessOptionsLocal() {\n";
+  O << "int PreprocessOptionsLocal() {\n";
 
   const RecordVector& OptionPreprocessors =
     Records.getAllDerivedDefinitions("OptionPreprocessor");
@@ -2640,13 +2645,15 @@ void EmitPreprocessOptions (const RecordKeeper& Records,
                              false, OptDecs, O);
   }
 
+  O << '\n';
+  O.indent(Indent1) << "return 0;\n";
   O << "}\n\n";
 }
 
 /// EmitPopulateLanguageMap - Emit the PopulateLanguageMapLocal() function.
 void EmitPopulateLanguageMap (const RecordKeeper& Records, raw_ostream& O)
 {
-  O << "void PopulateLanguageMapLocal(LanguageMap& langMap) {\n";
+  O << "int PopulateLanguageMapLocal(LanguageMap& langMap) {\n";
 
   // Get the relevant field out of RecordKeeper
   const Record* LangMapRecord = Records.getDef("LanguageMap");
@@ -2671,6 +2678,8 @@ void EmitPopulateLanguageMap (const RecordKeeper& Records, raw_ostream& O)
     }
   }
 
+  O << '\n';
+  O.indent(Indent1) << "return 0;\n";
   O << "}\n\n";
 }
 
@@ -2688,10 +2697,12 @@ void IncDecWeight (const Init* i, unsigned IndentLevel,
     O.indent(IndentLevel) << "ret -= ";
   }
   else if (OpName == "error") {
+    // TODO: fix this
     CheckNumberOfArguments(d, 1);
-    O.indent(IndentLevel) << "throw std::runtime_error(\""
+    O.indent(IndentLevel) << "PrintError(\""
                           << InitPtrToString(d.getArg(0))
                           << "\");\n";
+    O.indent(IndentLevel) << "return -1;\n";
     return;
   }
   else {
@@ -2752,7 +2763,7 @@ void EmitPopulateCompilationGraph (const RecordVector& EdgeVector,
                                    const ToolDescriptions& ToolDescs,
                                    raw_ostream& O)
 {
-  O << "void PopulateCompilationGraphLocal(CompilationGraph& G) {\n";
+  O << "int PopulateCompilationGraphLocal(CompilationGraph& G) {\n";
 
   for (ToolDescriptions::const_iterator B = ToolDescs.begin(),
          E = ToolDescs.end(); B != E; ++B)
@@ -2770,17 +2781,21 @@ void EmitPopulateCompilationGraph (const RecordVector& EdgeVector,
     const std::string& NodeB = Edge->getValueAsString("b");
     DagInit& Weight = *Edge->getValueAsDag("weight");
 
-    O.indent(Indent1) << "G.insertEdge(\"" << NodeA << "\", ";
+    O.indent(Indent1) << "if (int ret = G.insertEdge(\"" << NodeA << "\", ";
 
     if (IsDagEmpty(Weight))
       O << "new SimpleEdge(\"" << NodeB << "\")";
     else
       O << "new Edge" << i << "()";
 
-    O << ");\n";
+    O << "))\n";
+    O.indent(Indent2) << "return ret;\n";
+
     ++i;
   }
 
+  O << '\n';
+  O.indent(Indent1) << "return 0;\n";
   O << "}\n\n";
 }
 
@@ -2963,13 +2978,13 @@ void EmitRegisterPlugin(int Priority, raw_ostream& O) {
   O << "struct Plugin : public llvmc::BasePlugin {\n\n";
   O.indent(Indent1) << "int Priority() const { return "
                     << Priority << "; }\n\n";
-  O.indent(Indent1) << "void PreprocessOptions() const\n";
-  O.indent(Indent1) << "{ PreprocessOptionsLocal(); }\n\n";
-  O.indent(Indent1) << "void PopulateLanguageMap(LanguageMap& langMap) const\n";
-  O.indent(Indent1) << "{ PopulateLanguageMapLocal(langMap); }\n\n";
+  O.indent(Indent1) << "int PreprocessOptions() const\n";
+  O.indent(Indent1) << "{ return PreprocessOptionsLocal(); }\n\n";
+  O.indent(Indent1) << "int PopulateLanguageMap(LanguageMap& langMap) const\n";
+  O.indent(Indent1) << "{ return PopulateLanguageMapLocal(langMap); }\n\n";
   O.indent(Indent1)
-    << "void PopulateCompilationGraph(CompilationGraph& graph) const\n";
-  O.indent(Indent1) << "{ PopulateCompilationGraphLocal(graph); }\n"
+    << "int PopulateCompilationGraph(CompilationGraph& graph) const\n";
+  O.indent(Indent1) << "{ return PopulateCompilationGraphLocal(graph); }\n"
                     << "};\n\n"
                     << "static llvmc::RegisterPlugin<Plugin> RP;\n\n";
 }
@@ -2979,6 +2994,7 @@ void EmitRegisterPlugin(int Priority, raw_ostream& O) {
 void EmitIncludes(raw_ostream& O) {
   O << "#include \"llvm/CompilerDriver/BuiltinOptions.h\"\n"
     << "#include \"llvm/CompilerDriver/CompilationGraph.h\"\n"
+    << "#include \"llvm/CompilerDriver/Error.h\"\n"
     << "#include \"llvm/CompilerDriver/ForceLinkageMacros.h\"\n"
     << "#include \"llvm/CompilerDriver/Plugin.h\"\n"
     << "#include \"llvm/CompilerDriver/Tool.h\"\n\n"