X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=utils%2FTableGen%2FLLVMCConfigurationEmitter.cpp;h=fc9553ed268843cc99154315dd34bf029c150cf4;hb=15511cf1660cfd6bb8b8e8fca2db9450f50430ee;hp=8e4d870f76b13498d68d87e46eaf7821d84e14f8;hpb=5c98d824f681a5d531e619309faefbfa84e230fe;p=oota-llvm.git

diff --git a/utils/TableGen/LLVMCConfigurationEmitter.cpp b/utils/TableGen/LLVMCConfigurationEmitter.cpp
index 8e4d870f76b..fc9553ed268 100644
--- a/utils/TableGen/LLVMCConfigurationEmitter.cpp
+++ b/utils/TableGen/LLVMCConfigurationEmitter.cpp
@@ -1,4 +1,4 @@
-//===- LLVMCConfigurationEmitter.cpp - Generate LLVMC config --------------===//
+//===- LLVMCConfigurationEmitter.cpp - Generate LLVMC config ----*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -18,12 +18,15 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Streams.h"
 
 #include <algorithm>
 #include <cassert>
 #include <functional>
+#include <stdexcept>
 #include <string>
+#include <typeinfo>
 
 using namespace llvm;
 
@@ -53,37 +56,47 @@ const char * SinkOptionName = "AutoGeneratedSinkOption";
 //===----------------------------------------------------------------------===//
 /// Helper functions
 
-std::string InitPtrToString(Init* ptr) {
-  StringInit& val = dynamic_cast<StringInit&>(*ptr);
+int InitPtrToInt(const Init* ptr) {
+  const IntInit& val = dynamic_cast<const IntInit&>(*ptr);
   return val.getValue();
 }
 
-int InitPtrToInt(Init* ptr) {
-  IntInit& val = dynamic_cast<IntInit&>(*ptr);
+const std::string& InitPtrToString(const Init* ptr) {
+  const StringInit& val = dynamic_cast<const StringInit&>(*ptr);
   return val.getValue();
 }
 
-const DagInit& InitPtrToDagInitRef(Init* ptr) {
-  DagInit& val = dynamic_cast<DagInit&>(*ptr);
+const ListInit& InitPtrToList(const Init* ptr) {
+  const ListInit& val = dynamic_cast<const ListInit&>(*ptr);
   return val;
 }
 
+const DagInit& InitPtrToDag(const Init* ptr) {
+  const DagInit& val = dynamic_cast<const DagInit&>(*ptr);
+  return val;
+}
 
 // checkNumberOfArguments - Ensure that the number of args in d is
-// less than or equal to min_arguments, otherwise throw an exception .
+// less than or equal to min_arguments, otherwise throw an exception.
 void checkNumberOfArguments (const DagInit* d, unsigned min_arguments) {
   if (d->getNumArgs() < min_arguments)
     throw "Property " + d->getOperator()->getAsString()
       + " has too few arguments!";
 }
 
+// isDagEmpty - is this DAG marked with an empty marker?
+bool isDagEmpty (const DagInit* d) {
+  return d->getOperator()->getAsString() == "empty";
+}
 
 //===----------------------------------------------------------------------===//
 /// Back-end specific code
 
 // A command-line option can have one of the following types:
 //
-// Switch - a simple switch w/o arguments, e.g. -O2
+// Alias - an alias for another option.
+//
+// Switch - a simple switch without arguments, e.g. -O2
 //
 // Parameter - an option that takes one(and only one) argument, e.g. -o file,
 // --output=file
@@ -95,10 +108,11 @@ void checkNumberOfArguments (const DagInit* d, unsigned min_arguments) {
 // e.g. -Wa,-foo,-bar, -DNAME=VALUE
 //
 // PrefixList - same as Prefix, but more than one option occurence is
-// allowed
+// allowed.
 
 namespace OptionType {
-  enum OptionType { Switch, Parameter, ParameterList, Prefix, PrefixList};
+  enum OptionType { Alias, Switch,
+                    Parameter, ParameterList, Prefix, PrefixList};
 }
 
 bool IsListOptionType (OptionType::OptionType t) {
@@ -123,6 +137,8 @@ struct OptionDescription {
 
   const char* GenTypeDeclaration() const {
     switch (Type) {
+    case OptionType::Alias:
+      return "cl::alias";
     case OptionType::PrefixList:
     case OptionType::ParameterList:
       return "cl::list<std::string>";
@@ -141,11 +157,18 @@ struct OptionDescription {
   std::string EscapeVariableName(const std::string& Var) const {
     std::string ret;
     for (unsigned i = 0; i != Var.size(); ++i) {
-      if (Var[i] == ',') {
+      char cur_char = Var[i];
+      if (cur_char == ',') {
         ret += "_comma_";
       }
+      else if (cur_char == '+') {
+        ret += "_plus_";
+      }
+      else if (cur_char == '-') {
+        ret += "_dash_";
+      }
       else {
-        ret.push_back(Var[i]);
+        ret.push_back(cur_char);
       }
     }
     return ret;
@@ -154,18 +177,20 @@ struct OptionDescription {
   std::string GenVariableName() const {
     const std::string& EscapedName = EscapeVariableName(Name);
     switch (Type) {
+    case OptionType::Alias:
+     return "AutoGeneratedAlias" + EscapedName;
     case OptionType::Switch:
-     return "AutoGeneratedSwitch" + EscapedName;
-   case OptionType::Prefix:
-     return "AutoGeneratedPrefix" + EscapedName;
-   case OptionType::PrefixList:
-     return "AutoGeneratedPrefixList" + EscapedName;
-   case OptionType::Parameter:
-     return "AutoGeneratedParameter" + EscapedName;
-   case OptionType::ParameterList:
-   default:
-     return "AutoGeneratedParameterList" + EscapedName;
-   }
+      return "AutoGeneratedSwitch" + EscapedName;
+    case OptionType::Prefix:
+      return "AutoGeneratedPrefix" + EscapedName;
+    case OptionType::PrefixList:
+      return "AutoGeneratedPrefixList" + EscapedName;
+    case OptionType::Parameter:
+      return "AutoGeneratedParameter" + EscapedName;
+    case OptionType::ParameterList:
+    default:
+      return "AutoGeneratedParameterList" + EscapedName;
+    }
   }
 
 };
@@ -173,7 +198,8 @@ struct OptionDescription {
 // Global option description.
 
 namespace GlobalOptionDescriptionFlags {
-  enum GlobalOptionDescriptionFlags { Required = 0x1 };
+  enum GlobalOptionDescriptionFlags { Required = 0x1, Hidden = 0x2,
+                                      ReallyHidden = 0x4 };
 }
 
 struct GlobalOptionDescription : public OptionDescription {
@@ -185,8 +211,9 @@ struct GlobalOptionDescription : public OptionDescription {
   GlobalOptionDescription() : OptionDescription(), Flags(0)
   {}
 
-  GlobalOptionDescription (OptionType::OptionType t, const std::string& n)
-    : OptionDescription(t, n), Help(DefaultHelpString), Flags(0)
+  GlobalOptionDescription (OptionType::OptionType t, const std::string& n,
+                           const std::string& h = DefaultHelpString)
+    : OptionDescription(t, n), Help(h), Flags(0)
   {}
 
   bool isRequired() const {
@@ -196,17 +223,31 @@ struct GlobalOptionDescription : public OptionDescription {
     Flags |= GlobalOptionDescriptionFlags::Required;
   }
 
+  bool isHidden() const {
+    return Flags & GlobalOptionDescriptionFlags::Hidden;
+  }
+  void setHidden() {
+    Flags |= GlobalOptionDescriptionFlags::Hidden;
+  }
+
+  bool isReallyHidden() const {
+    return Flags & GlobalOptionDescriptionFlags::ReallyHidden;
+  }
+  void setReallyHidden() {
+    Flags |= GlobalOptionDescriptionFlags::ReallyHidden;
+  }
+
   /// Merge - Merge two option descriptions.
   void Merge (const GlobalOptionDescription& other)
   {
     if (other.Type != Type)
       throw "Conflicting definitions for the option " + Name + "!";
 
-    if (Help == DefaultHelpString)
+    if (Help == other.Help || Help == DefaultHelpString)
       Help = other.Help;
     else if (other.Help != DefaultHelpString) {
-      llvm::cerr << "Warning: more than one help string defined for option "
-        + Name + "\n";
+      llvm::cerr << "Warning: several different help strings"
+        " defined for option " + Name + "\n";
     }
 
     Flags |= other.Flags;
@@ -225,6 +266,7 @@ struct GlobalOptionDescriptions {
   /// HasSink - Should the emitter generate a "cl::sink" option?
   bool HasSink;
 
+  /// FindOption - exception-throwing wrapper for find().
   const GlobalOptionDescription& FindOption(const std::string& OptName) const {
     const_iterator I = Descriptions.find(OptName);
     if (I != Descriptions.end())
@@ -233,6 +275,20 @@ struct GlobalOptionDescriptions {
       throw OptName + ": no such option!";
   }
 
+  /// insertDescription - Insert new GlobalOptionDescription into
+  /// GlobalOptionDescriptions list
+  void insertDescription (const GlobalOptionDescription& o)
+  {
+    container_type::iterator I = Descriptions.find(o.Name);
+    if (I != Descriptions.end()) {
+      GlobalOptionDescription& D = I->second;
+      D.Merge(o);
+    }
+    else {
+      Descriptions[o.Name] = o;
+    }
+  }
+
   // Support for STL-style iteration
   const_iterator begin() const { return Descriptions.begin(); }
   const_iterator end() const { return Descriptions.end(); }
@@ -247,7 +303,7 @@ namespace ToolOptionDescriptionFlags {
                                     Forward = 0x2, UnpackValues = 0x4};
 }
 namespace OptionPropertyType {
-  enum OptionPropertyType { AppendCmd };
+  enum OptionPropertyType { AppendCmd, ForwardAs, OutputSuffix };
 }
 
 typedef std::pair<OptionPropertyType::OptionPropertyType, std::string>
@@ -304,8 +360,8 @@ namespace ToolFlags {
 
 struct ToolProperties : public RefCountedBase<ToolProperties> {
   std::string Name;
-  StrVector CmdLine;
-  std::string InLanguage;
+  Init* CmdLine;
+  StrVector InLanguage;
   std::string OutLanguage;
   std::string OutputSuffix;
   unsigned Flags;
@@ -319,8 +375,8 @@ struct ToolProperties : public RefCountedBase<ToolProperties> {
 
   // Default ctor here is needed because StringMap can only store
   // DefaultConstructible objects
-  ToolProperties() : Flags(0) {}
-  ToolProperties (const std::string& n) : Name(n), Flags(0) {}
+  ToolProperties() : CmdLine(0), Flags(0) {}
+  ToolProperties (const std::string& n) : Name(n), CmdLine(0), Flags(0) {}
 };
 
 
@@ -330,12 +386,253 @@ struct ToolProperties : public RefCountedBase<ToolProperties> {
 typedef std::vector<IntrusiveRefCntPtr<ToolProperties> > ToolPropertiesList;
 
 
+/// CollectOptionProperties - Function object for iterating over a
+/// list (usually, a DAG) of option property records.
+class CollectOptionProperties {
+private:
+  // Implementation details.
+
+  /// OptionPropertyHandler - a function that extracts information
+  /// about a given option property from its DAG representation.
+  typedef void (CollectOptionProperties::* OptionPropertyHandler)
+  (const DagInit*);
+
+  /// OptionPropertyHandlerMap - A map from option property names to
+  /// option property handlers
+  typedef StringMap<OptionPropertyHandler> OptionPropertyHandlerMap;
+
+  static OptionPropertyHandlerMap optionPropertyHandlers_;
+  static bool staticMembersInitialized_;
+
+  /// This is where the information is stored
+
+  /// toolProps_ -  Properties of the current Tool.
+  ToolProperties* toolProps_;
+  /// optDescs_ - OptionDescriptions table (used to register options
+  /// globally).
+  GlobalOptionDescription& optDesc_;
+
+public:
+
+  explicit CollectOptionProperties(ToolProperties* TP,
+                                   GlobalOptionDescription& OD)
+    : toolProps_(TP), optDesc_(OD)
+  {
+    if (!staticMembersInitialized_) {
+      optionPropertyHandlers_["append_cmd"] =
+        &CollectOptionProperties::onAppendCmd;
+      optionPropertyHandlers_["forward"] =
+        &CollectOptionProperties::onForward;
+      optionPropertyHandlers_["forward_as"] =
+        &CollectOptionProperties::onForwardAs;
+      optionPropertyHandlers_["help"] =
+        &CollectOptionProperties::onHelp;
+      optionPropertyHandlers_["hidden"] =
+        &CollectOptionProperties::onHidden;
+      optionPropertyHandlers_["output_suffix"] =
+        &CollectOptionProperties::onOutputSuffix;
+      optionPropertyHandlers_["really_hidden"] =
+        &CollectOptionProperties::onReallyHidden;
+      optionPropertyHandlers_["required"] =
+        &CollectOptionProperties::onRequired;
+      optionPropertyHandlers_["stop_compilation"] =
+        &CollectOptionProperties::onStopCompilation;
+      optionPropertyHandlers_["unpack_values"] =
+        &CollectOptionProperties::onUnpackValues;
+
+      staticMembersInitialized_ = true;
+    }
+  }
+
+  /// operator() - Gets called for every option property; Just forwards
+  /// to the corresponding property handler.
+  void operator() (Init* i) {
+    const DagInit& option_property = InitPtrToDag(i);
+    const std::string& option_property_name
+      = option_property.getOperator()->getAsString();
+    OptionPropertyHandlerMap::iterator method
+      = optionPropertyHandlers_.find(option_property_name);
+
+    if (method != optionPropertyHandlers_.end()) {
+      OptionPropertyHandler h = method->second;
+      (this->*h)(&option_property);
+    }
+    else {
+      throw "Unknown option property: " + option_property_name + "!";
+    }
+  }
+
+private:
+
+  /// Option property handlers --
+  /// Methods that handle properties that are common for all types of
+  /// options (like append_cmd, stop_compilation)
+
+  void onAppendCmd (const DagInit* d) {
+    checkNumberOfArguments(d, 1);
+    checkToolProps(d);
+    const std::string& cmd = InitPtrToString(d->getArg(0));
+
+    toolProps_->OptDescs[optDesc_.Name].
+      AddProperty(OptionPropertyType::AppendCmd, cmd);
+  }
+
+  void onOutputSuffix (const DagInit* d) {
+    checkNumberOfArguments(d, 1);
+    checkToolProps(d);
+    const std::string& suf = InitPtrToString(d->getArg(0));
+
+    if (toolProps_->OptDescs[optDesc_.Name].Type != OptionType::Switch)
+      throw "Option " + optDesc_.Name
+        + " can't have 'output_suffix' property since it isn't a switch!";
+
+    toolProps_->OptDescs[optDesc_.Name].AddProperty
+      (OptionPropertyType::OutputSuffix, suf);
+  }
+
+  void onForward (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    toolProps_->OptDescs[optDesc_.Name].setForward();
+  }
+
+  void onForwardAs (const DagInit* d) {
+    checkNumberOfArguments(d, 1);
+    checkToolProps(d);
+    const std::string& cmd = InitPtrToString(d->getArg(0));
+
+    toolProps_->OptDescs[optDesc_.Name].
+      AddProperty(OptionPropertyType::ForwardAs, cmd);
+  }
+
+  void onHelp (const DagInit* d) {
+    checkNumberOfArguments(d, 1);
+    const std::string& help_message = InitPtrToString(d->getArg(0));
+
+    optDesc_.Help = help_message;
+  }
+
+  void onHidden (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    optDesc_.setHidden();
+  }
+
+  void onReallyHidden (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    optDesc_.setReallyHidden();
+  }
+
+  void onRequired (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    optDesc_.setRequired();
+  }
+
+  void onStopCompilation (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    if (optDesc_.Type != OptionType::Switch)
+      throw std::string("Only options of type Switch can stop compilation!");
+    toolProps_->OptDescs[optDesc_.Name].setStopCompilation();
+  }
+
+  void onUnpackValues (const DagInit* d) {
+    checkNumberOfArguments(d, 0);
+    checkToolProps(d);
+    toolProps_->OptDescs[optDesc_.Name].setUnpackValues();
+  }
+
+  // Helper functions
+
+  /// checkToolProps - Throw an error if toolProps_ == 0.
+  void checkToolProps(const DagInit* d) {
+    if (!d)
+      throw "Option property " + d->getOperator()->getAsString()
+        + " can't be used in this context";
+  }
+
+};
+
+CollectOptionProperties::OptionPropertyHandlerMap
+CollectOptionProperties::optionPropertyHandlers_;
+
+bool CollectOptionProperties::staticMembersInitialized_ = false;
+
+
+/// processOptionProperties - Go through the list of option
+/// properties and call a corresponding handler for each.
+void processOptionProperties (const DagInit* d, ToolProperties* t,
+                              GlobalOptionDescription& o) {
+  checkNumberOfArguments(d, 2);
+  DagInit::const_arg_iterator B = d->arg_begin();
+  // Skip the first argument: it's always the option name.
+  ++B;
+  std::for_each(B, d->arg_end(), CollectOptionProperties(t, o));
+}
+
+/// AddOption - A function object wrapper for
+/// processOptionProperties. Used by CollectProperties and
+/// CollectPropertiesFromOptionList.
+class AddOption {
+private:
+  GlobalOptionDescriptions& OptDescs_;
+  ToolProperties* ToolProps_;
+
+public:
+  explicit AddOption(GlobalOptionDescriptions& OD, ToolProperties* TP = 0)
+    : OptDescs_(OD), ToolProps_(TP)
+  {}
+
+  void operator()(const Init* i) {
+    const DagInit& d = InitPtrToDag(i);
+    checkNumberOfArguments(&d, 2);
+
+    const OptionType::OptionType Type =
+      getOptionType(d.getOperator()->getAsString());
+    const std::string& Name = InitPtrToString(d.getArg(0));
+
+    GlobalOptionDescription OD(Type, Name);
+    if (Type != OptionType::Alias) {
+      processOptionProperties(&d, ToolProps_, OD);
+      if (ToolProps_) {
+        ToolProps_->OptDescs[Name].Type = Type;
+        ToolProps_->OptDescs[Name].Name = Name;
+      }
+    }
+    else {
+      OD.Help = InitPtrToString(d.getArg(1));
+    }
+    OptDescs_.insertDescription(OD);
+  }
+
+private:
+  OptionType::OptionType getOptionType(const std::string& T) const {
+    if (T == "alias_option")
+      return OptionType::Alias;
+    else if (T == "switch_option")
+      return OptionType::Switch;
+    else if (T == "parameter_option")
+      return OptionType::Parameter;
+    else if (T == "parameter_list_option")
+      return OptionType::ParameterList;
+    else if (T == "prefix_option")
+      return OptionType::Prefix;
+    else if (T == "prefix_list_option")
+      return OptionType::PrefixList;
+    else
+      throw "Unknown option type: " + T + '!';
+  }
+};
+
+
 /// CollectProperties - Function object for iterating over a list of
 /// tool property records.
 class CollectProperties {
 private:
 
-  /// Implementation details
+  // Implementation details
 
   /// PropertyHandler - a function that extracts information
   /// about a given tool property from its DAG representation
@@ -345,18 +642,8 @@ private:
   /// handlers.
   typedef StringMap<PropertyHandler> PropertyHandlerMap;
 
-  /// OptionPropertyHandler - a function that extracts information
-  /// about a given option property from its DAG representation.
-  typedef void (CollectProperties::* OptionPropertyHandler)
-  (const DagInit*, GlobalOptionDescription &);
-
-  /// OptionPropertyHandlerMap - A map from option property names to
-  /// option property handlers
-  typedef StringMap<OptionPropertyHandler> OptionPropertyHandlerMap;
-
   // Static maps from strings to CollectProperties methods("handlers")
   static PropertyHandlerMap propertyHandlers_;
-  static OptionPropertyHandlerMap optionPropertyHandlers_;
   static bool staticMembersInitialized_;
 
 
@@ -374,31 +661,21 @@ public:
     : toolProps_(p), optDescs_(d)
   {
     if (!staticMembersInitialized_) {
-      // Init tool property handlers
       propertyHandlers_["cmd_line"] = &CollectProperties::onCmdLine;
       propertyHandlers_["in_language"] = &CollectProperties::onInLanguage;
       propertyHandlers_["join"] = &CollectProperties::onJoin;
       propertyHandlers_["out_language"] = &CollectProperties::onOutLanguage;
       propertyHandlers_["output_suffix"] = &CollectProperties::onOutputSuffix;
       propertyHandlers_["parameter_option"]
-        = &CollectProperties::onParameter;
+        = &CollectProperties::addOption;
       propertyHandlers_["parameter_list_option"] =
-        &CollectProperties::onParameterList;
-      propertyHandlers_["prefix_option"] = &CollectProperties::onPrefix;
+        &CollectProperties::addOption;
+      propertyHandlers_["prefix_option"] = &CollectProperties::addOption;
       propertyHandlers_["prefix_list_option"] =
-        &CollectProperties::onPrefixList;
+        &CollectProperties::addOption;
       propertyHandlers_["sink"] = &CollectProperties::onSink;
-      propertyHandlers_["switch_option"] = &CollectProperties::onSwitch;
-
-      // Init option property handlers
-      optionPropertyHandlers_["append_cmd"] = &CollectProperties::onAppendCmd;
-      optionPropertyHandlers_["forward"] = &CollectProperties::onForward;
-      optionPropertyHandlers_["help"] = &CollectProperties::onHelp;
-      optionPropertyHandlers_["required"] = &CollectProperties::onRequired;
-      optionPropertyHandlers_["stop_compilation"] =
-        &CollectProperties::onStopCompilation;
-      optionPropertyHandlers_["unpack_values"] =
-        &CollectProperties::onUnpackValues;
+      propertyHandlers_["switch_option"] = &CollectProperties::addOption;
+      propertyHandlers_["alias_option"] = &CollectProperties::addOption;
 
       staticMembersInitialized_ = true;
     }
@@ -407,7 +684,7 @@ public:
   /// operator() - Gets called for every tool property; Just forwards
   /// to the corresponding property handler.
   void operator() (Init* i) {
-    const DagInit& d = InitPtrToDagInitRef(i);
+    const DagInit& d = InitPtrToDag(i);
     const std::string& property_name = d.getOperator()->getAsString();
     PropertyHandlerMap::iterator method
       = propertyHandlers_.find(property_name);
@@ -429,14 +706,34 @@ private:
 
   void onCmdLine (const DagInit* d) {
     checkNumberOfArguments(d, 1);
-    SplitString(InitPtrToString(d->getArg(0)), toolProps_.CmdLine);
-    if (toolProps_.CmdLine.empty())
-      throw "Tool " + toolProps_.Name + " has empty command line!";
+    toolProps_.CmdLine = d->getArg(0);
   }
 
   void onInLanguage (const DagInit* d) {
     checkNumberOfArguments(d, 1);
-    toolProps_.InLanguage = InitPtrToString(d->getArg(0));
+    Init* arg = d->getArg(0);
+
+    // Find out the argument's type.
+    if (typeid(*arg) == typeid(StringInit)) {
+      // It's a string.
+      toolProps_.InLanguage.push_back(InitPtrToString(arg));
+    }
+    else {
+      // It's a list.
+      const ListInit& lst = InitPtrToList(arg);
+      StrVector& out = toolProps_.InLanguage;
+
+      // Copy strings to the output vector.
+      for (ListInit::const_iterator B = lst.begin(), E = lst.end();
+           B != E; ++B) {
+        out.push_back(InitPtrToString(*B));
+      }
+
+      // Remove duplicates.
+      std::sort(out.begin(), out.end());
+      StrVector::iterator newE = std::unique(out.begin(), out.end());
+      out.erase(newE, out.end());
+    }
   }
 
   void onJoin (const DagInit* d) {
@@ -460,175 +757,284 @@ private:
     toolProps_.setSink();
   }
 
-  void onSwitch (const DagInit* d) {
-    addOption(d, OptionType::Switch);
-  }
-
-  void onParameter (const DagInit* d) {
-    addOption(d, OptionType::Parameter);
-  }
-
-  void onParameterList (const DagInit* d) {
-    addOption(d, OptionType::ParameterList);
+  // Just forwards to the AddOption function object. Somewhat
+  // non-optimal, but avoids code duplication.
+  void addOption (const DagInit* d) {
+    checkNumberOfArguments(d, 2);
+    AddOption(optDescs_, &toolProps_)(d);
   }
 
-  void onPrefix (const DagInit* d) {
-    addOption(d, OptionType::Prefix);
-  }
+};
 
-  void onPrefixList (const DagInit* d) {
-    addOption(d, OptionType::PrefixList);
-  }
+// Defintions of static members of CollectProperties.
+CollectProperties::PropertyHandlerMap CollectProperties::propertyHandlers_;
+bool CollectProperties::staticMembersInitialized_ = false;
 
-  /// Option property handlers --
-  /// Methods that handle properties that are common for all types of
-  /// options (like append_cmd, stop_compilation)
 
-  void onAppendCmd (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 1);
-    std::string const& cmd = InitPtrToString(d->getArg(0));
+/// CollectToolProperties - Gather information about tool properties
+/// from the parsed TableGen data (basically a wrapper for the
+/// CollectProperties function object).
+void CollectToolProperties (RecordVector::const_iterator B,
+                            RecordVector::const_iterator E,
+                            ToolPropertiesList& TPList,
+                            GlobalOptionDescriptions& OptDescs)
+{
+  // Iterate over a properties list of every Tool definition
+  for (;B!=E;++B) {
+    const Record* T = *B;
+    // Throws an exception if the value does not exist.
+    ListInit* PropList = T->getValueAsListInit("properties");
 
-    toolProps_.OptDescs[o.Name].AddProperty(OptionPropertyType::AppendCmd, cmd);
-  }
+    IntrusiveRefCntPtr<ToolProperties>
+      ToolProps(new ToolProperties(T->getName()));
 
-  void onForward (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 0);
-    toolProps_.OptDescs[o.Name].setForward();
+    std::for_each(PropList->begin(), PropList->end(),
+                  CollectProperties(*ToolProps, OptDescs));
+    TPList.push_back(ToolProps);
   }
+}
 
-  void onHelp (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 1);
-    const std::string& help_message = InitPtrToString(d->getArg(0));
 
-    o.Help = help_message;
-  }
+/// CollectPropertiesFromOptionLists - Gather information about
+/// *global* option properties from all OptionLists.
+void CollectPropertiesFromOptionLists (RecordVector::const_iterator B,
+                                       RecordVector::const_iterator E,
+                                       GlobalOptionDescriptions& OptDescs)
+{
+  // Iterate over a properties list of every Tool definition
+  for (; B!=E; ++B) {
+    RecordVector::value_type T = *B;
+    // Throws an exception if the value does not exist.
+    ListInit* PropList = T->getValueAsListInit("options");
 
-  void onRequired (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 0);
-    o.setRequired();
+    std::for_each(PropList->begin(), PropList->end(), AddOption(OptDescs));
   }
+}
 
-  void onStopCompilation (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 0);
-    if (o.Type != OptionType::Switch)
-      throw std::string("Only options of type Switch can stop compilation!");
-    toolProps_.OptDescs[o.Name].setStopCompilation();
+/// CheckForSuperfluousOptions - Check that there are no side
+/// effect-free options (specified only in the OptionList). Otherwise,
+/// output a warning.
+void CheckForSuperfluousOptions (const ToolPropertiesList& TPList,
+                                 const GlobalOptionDescriptions& OptDescs) {
+  llvm::StringSet<> nonSuperfluousOptions;
+
+  // Add all options mentioned in the TPList to the set of
+  // non-superfluous options.
+  for (ToolPropertiesList::const_iterator B = TPList.begin(),
+         E = TPList.end(); B != E; ++B) {
+    const ToolProperties& TP = *(*B);
+    for (ToolOptionDescriptions::const_iterator B = TP.OptDescs.begin(),
+           E = TP.OptDescs.end(); B != E; ++B) {
+      nonSuperfluousOptions.insert(B->first());
+    }
   }
 
-  void onUnpackValues (const DagInit* d, GlobalOptionDescription& o) {
-    checkNumberOfArguments(d, 0);
-    toolProps_.OptDescs[o.Name].setUnpackValues();
+  // Check that all options in OptDescs belong to the set of
+  // non-superfluous options.
+  for (GlobalOptionDescriptions::const_iterator B = OptDescs.begin(),
+         E = OptDescs.end(); B != E; ++B) {
+    const GlobalOptionDescription& Val = B->second;
+    if (!nonSuperfluousOptions.count(Val.Name)
+        && Val.Type != OptionType::Alias)
+      llvm::cerr << "Warning: option '-" << Val.Name << "' has no effect! "
+        "Probable cause: this option is specified only in the OptionList.\n";
   }
+}
 
-  /// Helper functions
-
-  // Add an option of type t
-  void addOption (const DagInit* d, OptionType::OptionType t) {
-    checkNumberOfArguments(d, 2);
-    const std::string& name = InitPtrToString(d->getArg(0));
-
-    GlobalOptionDescription o(t, name);
-    toolProps_.OptDescs[name].Type = t;
-    toolProps_.OptDescs[name].Name = name;
-    processOptionProperties(d, o);
-    insertDescription(o);
-  }
+/// EmitCaseTest1Arg - Helper function used by
+/// EmitCaseConstructHandler.
+bool EmitCaseTest1Arg(const std::string& TestName,
+                      const DagInit& d,
+                      const GlobalOptionDescriptions& OptDescs,
+                      std::ostream& O) {
+  checkNumberOfArguments(&d, 1);
+  const std::string& OptName = InitPtrToString(d.getArg(0));
+  if (TestName == "switch_on") {
+    const GlobalOptionDescription& OptDesc = OptDescs.FindOption(OptName);
+    if (OptDesc.Type != OptionType::Switch)
+      throw OptName + ": incorrect option type!";
+    O << OptDesc.GenVariableName();
+    return true;
+  } else if (TestName == "input_languages_contain") {
+    O << "InLangs.count(\"" << OptName << "\") != 0";
+    return true;
+  } else if (TestName == "in_language") {
+    // This works only for single-argument Tool::GenerateAction. Join
+    // tools can process several files in different languages simultaneously.
 
-  // Insert new GlobalOptionDescription into GlobalOptionDescriptions list
-  void insertDescription (const GlobalOptionDescription& o)
-  {
-    if (optDescs_.Descriptions.count(o.Name)) {
-      GlobalOptionDescription& D = optDescs_.Descriptions[o.Name];
-      D.Merge(o);
+    // TODO: make this work with Edge::Weight (if possible).
+    O << "LangMap.GetLanguage(inFile) == \"" << OptName << '\"';
+    return true;
+  } else if (TestName == "not_empty") {
+    if (OptName == "o") {
+      O << "!OutputFilename.empty()";
+      return true;
     }
     else {
-      optDescs_.Descriptions[o.Name] = o;
+      const GlobalOptionDescription& OptDesc = OptDescs.FindOption(OptName);
+      if (OptDesc.Type == OptionType::Switch)
+        throw OptName + ": incorrect option type!";
+      O << '!' << OptDesc.GenVariableName() << ".empty()";
+      return true;
     }
   }
 
-  /// processOptionProperties - Go through the list of option
-  /// properties and call a corresponding handler for each.
-  ///
-  /// Parameters:
-  /// name - option name
-  /// d - option property list
-  void processOptionProperties (const DagInit* d, GlobalOptionDescription& o) {
-    // First argument is option name
-    checkNumberOfArguments(d, 2);
+  return false;
+}
 
-    for (unsigned B = 1, E = d->getNumArgs(); B!=E; ++B) {
-      const DagInit& option_property
-        = InitPtrToDagInitRef(d->getArg(B));
-      const std::string& option_property_name
-        = option_property.getOperator()->getAsString();
-      OptionPropertyHandlerMap::iterator method
-        = optionPropertyHandlers_.find(option_property_name);
-
-      if (method != optionPropertyHandlers_.end()) {
-        OptionPropertyHandler h = method->second;
-        (this->*h)(&option_property, o);
-      }
-      else {
-        throw "Unknown option property: " + option_property_name + "!";
-      }
-    }
-  }
-};
+/// EmitCaseTest2Args - Helper function used by
+/// EmitCaseConstructHandler.
+bool EmitCaseTest2Args(const std::string& TestName,
+                       const DagInit& d,
+                       const char* IndentLevel,
+                       const GlobalOptionDescriptions& OptDescs,
+                       std::ostream& O) {
+  checkNumberOfArguments(&d, 2);
+  const std::string& OptName = InitPtrToString(d.getArg(0));
+  const std::string& OptArg = InitPtrToString(d.getArg(1));
+  const GlobalOptionDescription& OptDesc = OptDescs.FindOption(OptName);
 
-// Static members of CollectProperties
-CollectProperties::PropertyHandlerMap
-CollectProperties::propertyHandlers_;
+  if (TestName == "parameter_equals") {
+    if (OptDesc.Type != OptionType::Parameter
+        && OptDesc.Type != OptionType::Prefix)
+      throw OptName + ": incorrect option type!";
+    O << OptDesc.GenVariableName() << " == \"" << OptArg << "\"";
+    return true;
+  }
+  else if (TestName == "element_in_list") {
+    if (OptDesc.Type != OptionType::ParameterList
+        && OptDesc.Type != OptionType::PrefixList)
+      throw OptName + ": incorrect option type!";
+    const std::string& VarName = OptDesc.GenVariableName();
+    O << "std::find(" << VarName << ".begin(),\n"
+      << IndentLevel << Indent1 << VarName << ".end(), \""
+      << OptArg << "\") != " << VarName << ".end()";
+    return true;
+  }
 
-CollectProperties::OptionPropertyHandlerMap
-CollectProperties::optionPropertyHandlers_;
+  return false;
+}
 
-bool CollectProperties::staticMembersInitialized_ = false;
+// Forward declaration.
+// EmitLogicalOperationTest and EmitCaseTest are mutually recursive.
+void EmitCaseTest(const DagInit& d, const char* IndentLevel,
+                  const GlobalOptionDescriptions& OptDescs,
+                  std::ostream& O);
 
+/// EmitLogicalOperationTest - Helper function used by
+/// EmitCaseConstructHandler.
+void EmitLogicalOperationTest(const DagInit& d, const char* LogicOp,
+                              const char* IndentLevel,
+                              const GlobalOptionDescriptions& OptDescs,
+                              std::ostream& O) {
+  O << '(';
+  for (unsigned j = 0, NumArgs = d.getNumArgs(); j < NumArgs; ++j) {
+    const DagInit& InnerTest = InitPtrToDag(d.getArg(j));
+    EmitCaseTest(InnerTest, IndentLevel, OptDescs, O);
+    if (j != NumArgs - 1)
+      O << ")\n" << IndentLevel << Indent1 << ' ' << LogicOp << " (";
+    else
+      O << ')';
+  }
+}
 
-/// CollectToolProperties - Gather information from the parsed
-/// TableGen data (basically a wrapper for the CollectProperties
-/// function object).
-void CollectToolProperties (RecordVector::const_iterator B,
-                            RecordVector::const_iterator E,
-                            ToolPropertiesList& TPList,
-                            GlobalOptionDescriptions& OptDescs)
-{
-  // Iterate over a properties list of every Tool definition
-  for (;B!=E;++B) {
-    RecordVector::value_type T = *B;
-    ListInit* PropList = T->getValueAsListInit("properties");
+/// EmitCaseTest - Helper function used by EmitCaseConstructHandler.
+void EmitCaseTest(const DagInit& d, const char* IndentLevel,
+                  const GlobalOptionDescriptions& OptDescs,
+                  std::ostream& O) {
+  const std::string& TestName = d.getOperator()->getAsString();
+
+  if (TestName == "and")
+    EmitLogicalOperationTest(d, "&&", IndentLevel, OptDescs, O);
+  else if (TestName == "or")
+    EmitLogicalOperationTest(d, "||", IndentLevel, OptDescs, O);
+  else if (EmitCaseTest1Arg(TestName, d, OptDescs, O))
+    return;
+  else if (EmitCaseTest2Args(TestName, d, IndentLevel, OptDescs, O))
+    return;
+  else
+    throw TestName + ": unknown edge property!";
+}
 
-    IntrusiveRefCntPtr<ToolProperties>
-      ToolProps(new ToolProperties(T->getName()));
+// Emit code that handles the 'case' construct.
+// Takes a function object that should emit code for every case clause.
+// Callback's type is
+// void F(Init* Statement, const char* IndentLevel, std::ostream& O).
+template <typename F>
+void EmitCaseConstructHandler(const DagInit* d, const char* IndentLevel,
+                              F Callback, bool EmitElseIf,
+                              const GlobalOptionDescriptions& OptDescs,
+                              std::ostream& O) {
+  assert(d->getOperator()->getAsString() == "case");
+
+  unsigned numArgs = d->getNumArgs();
+  if (d->getNumArgs() < 2)
+    throw "There should be at least one clause in the 'case' expression:\n"
+      + d->getAsString();
+
+  for (unsigned i = 0; i != numArgs; ++i) {
+    const DagInit& Test = InitPtrToDag(d->getArg(i));
+
+    // Emit the test.
+    if (Test.getOperator()->getAsString() == "default") {
+      if (i+2 != numArgs)
+        throw std::string("The 'default' clause should be the last in the"
+                          "'case' construct!");
+      O << IndentLevel << "else {\n";
+    }
+    else {
+      O << IndentLevel << ((i != 0 && EmitElseIf) ? "else if (" : "if (");
+      EmitCaseTest(Test, IndentLevel, OptDescs, O);
+      O << ") {\n";
+    }
 
-    std::for_each(PropList->begin(), PropList->end(),
-                  CollectProperties(*ToolProps, OptDescs));
-    TPList.push_back(ToolProps);
+    // Emit the corresponding statement.
+    ++i;
+    if (i == numArgs)
+      throw "Case construct handler: no corresponding action "
+        "found for the test " + Test.getAsString() + '!';
+
+    Init* arg = d->getArg(i);
+    if (dynamic_cast<DagInit*>(arg)
+        && static_cast<DagInit*>(arg)->getOperator()->getAsString() == "case") {
+      EmitCaseConstructHandler(static_cast<DagInit*>(arg),
+                               (std::string(IndentLevel) + Indent1).c_str(),
+                               Callback, EmitElseIf, OptDescs, O);
+    }
+    else {
+      Callback(arg, IndentLevel, O);
+    }
+    O << IndentLevel << "}\n";
   }
 }
 
 /// EmitForwardOptionPropertyHandlingCode - Helper function used to
 /// implement EmitOptionPropertyHandlingCode(). Emits code for
-/// handling the (forward) option property.
+/// handling the (forward) and (forward_as) option properties.
 void EmitForwardOptionPropertyHandlingCode (const ToolOptionDescription& D,
+                                            const std::string& NewName,
                                             std::ostream& O) {
+  const std::string& Name = NewName.empty()
+    ? ("-" + D.Name)
+    : NewName;
+
   switch (D.Type) {
   case OptionType::Switch:
-    O << Indent3 << "vec.push_back(\"-" << D.Name << "\");\n";
+    O << Indent3 << "vec.push_back(\"" << Name << "\");\n";
     break;
   case OptionType::Parameter:
-    O << Indent3 << "vec.push_back(\"-" << D.Name << "\");\n";
+    O << Indent3 << "vec.push_back(\"" << Name << "\");\n";
     O << Indent3 << "vec.push_back(" << D.GenVariableName() << ");\n";
     break;
   case OptionType::Prefix:
-    O << Indent3 << "vec.push_back(\"-" << D.Name << "\" + "
+    O << Indent3 << "vec.push_back(\"" << Name << "\" + "
       << D.GenVariableName() << ");\n";
     break;
   case OptionType::PrefixList:
     O << Indent3 << "for (" << D.GenTypeDeclaration()
       << "::iterator B = " << D.GenVariableName() << ".begin(),\n"
       << Indent3 << "E = " << D.GenVariableName() << ".end(); B != E; ++B)\n"
-      << Indent4 << "vec.push_back(\"-" << D.Name << "\" + "
+      << Indent4 << "vec.push_back(\"" << Name << "\" + "
       << "*B);\n";
     break;
   case OptionType::ParameterList:
@@ -636,20 +1042,41 @@ void EmitForwardOptionPropertyHandlingCode (const ToolOptionDescription& D,
       << "::iterator B = " << D.GenVariableName() << ".begin(),\n"
       << Indent3 << "E = " << D.GenVariableName()
       << ".end() ; B != E; ++B) {\n"
-      << Indent4 << "vec.push_back(\"-" << D.Name << "\");\n"
+      << Indent4 << "vec.push_back(\"" << Name << "\");\n"
       << Indent4 << "vec.push_back(*B);\n"
       << Indent3 << "}\n";
     break;
+  case OptionType::Alias:
+  default:
+    throw std::string("Aliases are not allowed in tool option descriptions!");
   }
 }
 
+// ToolOptionHasInterestingProperties - A helper function used by
+// EmitOptionPropertyHandlingCode() that tells us whether we should
+// emit any property handling code at all.
+bool ToolOptionHasInterestingProperties(const ToolOptionDescription& D) {
+  bool ret = false;
+  for (OptionPropertyList::const_iterator B = D.Props.begin(),
+         E = D.Props.end(); B != E; ++B) {
+      const OptionProperty& OptProp = *B;
+      if (OptProp.first == OptionPropertyType::AppendCmd
+          || OptProp.first == OptionPropertyType::ForwardAs)
+        ret = true;
+    }
+  if (D.isForward() || D.isUnpackValues())
+    ret = true;
+  return ret;
+}
+
 /// EmitOptionPropertyHandlingCode - Helper function used by
 /// EmitGenerateActionMethod(). Emits code that handles option
 /// properties.
-void EmitOptionPropertyHandlingCode (const ToolProperties& P,
-                                     const ToolOptionDescription& D,
+void EmitOptionPropertyHandlingCode (const ToolOptionDescription& D,
                                      std::ostream& O)
 {
+  if (!ToolOptionHasInterestingProperties(D))
+    return;
   // Start of the if-clause.
   O << Indent2 << "if (";
   if (D.Type == OptionType::Switch)
@@ -669,6 +1096,10 @@ void EmitOptionPropertyHandlingCode (const ToolProperties& P,
     case OptionPropertyType::AppendCmd:
       O << Indent3 << "vec.push_back(\"" << val.second << "\");\n";
       break;
+      // (forward_as) property
+    case OptionPropertyType::ForwardAs:
+      EmitForwardOptionPropertyHandlingCode(D, val.second, O);
+      break;
       // Other properties with argument
     default:
       break;
@@ -679,7 +1110,7 @@ void EmitOptionPropertyHandlingCode (const ToolProperties& P,
 
   // (forward) property
   if (D.isForward())
-    EmitForwardOptionPropertyHandlingCode(D, O);
+    EmitForwardOptionPropertyHandlingCode(D, "", O);
 
   // (unpack_values) property
   if (D.isUnpackValues()) {
@@ -695,7 +1126,6 @@ void EmitOptionPropertyHandlingCode (const ToolProperties& P,
         << D.GenVariableName() << ", vec, \",\");\n";
     }
     else {
-      // TOFIX: move this to the type-checking phase
       throw std::string("Switches can't have unpack_values property!");
     }
   }
@@ -704,50 +1134,132 @@ void EmitOptionPropertyHandlingCode (const ToolProperties& P,
   O << Indent2 << "}\n";
 }
 
-// EmitGenerateActionMethod - Emit one of two versions of the
-// Tool::GenerateAction() method.
-void EmitGenerateActionMethod (const ToolProperties& P, bool V, std::ostream& O)
-{
-  if (V)
-    O << Indent1 << "Action GenerateAction(const PathVector& inFiles,\n";
-  else
-    O << Indent1 << "Action GenerateAction(const sys::Path& inFile,\n";
+/// SubstituteSpecialCommands - Perform string substitution for $CALL
+/// and $ENV. Helper function used by EmitCmdLineVecFill().
+std::string SubstituteSpecialCommands(const std::string& cmd) {
+  size_t cparen = cmd.find(")");
+  std::string ret;
 
-  O << Indent2 << "const sys::Path& outFile) const\n"
-    << Indent1 << "{\n"
-    << Indent2 << "std::vector<std::string> vec;\n";
+  if (cmd.find("$CALL(") == 0) {
+    if (cmd.size() == 6)
+      throw std::string("$CALL invocation: empty argument list!");
+
+    ret += "hooks::";
+    ret += std::string(cmd.begin() + 6, cmd.begin() + cparen);
+    ret += "()";
+  }
+  else if (cmd.find("$ENV(") == 0) {
+    if (cmd.size() == 5)
+      throw std::string("$ENV invocation: empty argument list!");
 
-  // Parse CmdLine tool property
-  if(P.CmdLine.empty())
-    throw "Tool " + P.Name + " has empty command line!";
+    ret += "checkCString(std::getenv(\"";
+    ret += std::string(cmd.begin() + 5, cmd.begin() + cparen);
+    ret += "\"))";
+  }
+  else {
+    throw "Unknown special command: " + cmd;
+  }
 
-  StrVector::const_iterator I = P.CmdLine.begin();
+  if (cmd.begin() + cparen + 1 != cmd.end()) {
+    ret += " + std::string(\"";
+    ret += (cmd.c_str() + cparen + 1);
+    ret += "\")";
+  }
+
+  return ret;
+}
+
+/// EmitCmdLineVecFill - Emit code that fills in the command line
+/// vector. Helper function used by EmitGenerateActionMethod().
+void EmitCmdLineVecFill(const Init* CmdLine, const std::string& ToolName,
+                        bool Version, const char* IndentLevel,
+                        std::ostream& O) {
+  StrVector StrVec;
+  SplitString(InitPtrToString(CmdLine), StrVec);
+  if (StrVec.empty())
+    throw "Tool " + ToolName + " has empty command line!";
+
+  StrVector::const_iterator I = StrVec.begin();
   ++I;
-  for (StrVector::const_iterator E = P.CmdLine.end(); I != E; ++I) {
+  for (StrVector::const_iterator E = StrVec.end(); I != E; ++I) {
     const std::string& cmd = *I;
-    O << Indent2;
-    if (cmd == "$INFILE") {
-      if (V)
-        O << "for (PathVector::const_iterator B = inFiles.begin()"
-          << ", E = inFiles.end();\n"
-          << Indent2 << "B != E; ++B)\n"
-          << Indent3 << "vec.push_back(B->toString());\n";
-      else
-        O << "vec.push_back(inFile.toString());\n";
-    }
-    else if (cmd == "$OUTFILE") {
-      O << "vec.push_back(outFile.toString());\n";
+    O << IndentLevel;
+    if (cmd.at(0) == '$') {
+      if (cmd == "$INFILE") {
+        if (Version)
+          O << "for (PathVector::const_iterator B = inFiles.begin()"
+            << ", E = inFiles.end();\n"
+            << IndentLevel << "B != E; ++B)\n"
+            << IndentLevel << Indent1 << "vec.push_back(B->toString());\n";
+        else
+          O << "vec.push_back(inFile.toString());\n";
+      }
+      else if (cmd == "$OUTFILE") {
+        O << "vec.push_back(outFile.toString());\n";
+      }
+      else {
+        O << "vec.push_back(" << SubstituteSpecialCommands(cmd);
+        O << ");\n";
+      }
     }
     else {
       O << "vec.push_back(\"" << cmd << "\");\n";
     }
   }
+  O << IndentLevel << "cmd = "
+    << ((StrVec[0][0] == '$') ? SubstituteSpecialCommands(StrVec[0])
+        : "\"" + StrVec[0] + "\"")
+    << ";\n";
+}
+
+/// EmitCmdLineVecFillCallback - A function object wrapper around
+/// EmitCmdLineVecFill(). Used by EmitGenerateActionMethod() as an
+/// argument to EmitCaseConstructHandler().
+class EmitCmdLineVecFillCallback {
+  bool Version;
+  const std::string& ToolName;
+ public:
+  EmitCmdLineVecFillCallback(bool Ver, const std::string& TN)
+    : Version(Ver), ToolName(TN) {}
+
+  void operator()(const Init* Statement, const char* IndentLevel,
+                  std::ostream& O) const
+  {
+    EmitCmdLineVecFill(Statement, ToolName, Version,
+                       (std::string(IndentLevel) + Indent1).c_str(), O);
+  }
+};
+
+// EmitGenerateActionMethod - Emit one of two versions of the
+// Tool::GenerateAction() method.
+void EmitGenerateActionMethod (const ToolProperties& P,
+                               const GlobalOptionDescriptions& OptDescs,
+                               bool Version, std::ostream& O) {
+  if (Version)
+    O << Indent1 << "Action GenerateAction(const PathVector& inFiles,\n";
+  else
+    O << Indent1 << "Action GenerateAction(const sys::Path& inFile,\n";
+
+  O << Indent2 << "const sys::Path& outFile,\n"
+    << Indent2 << "const InputLanguagesSet& InLangs,\n"
+    << Indent2 << "const LanguageMap& LangMap) const\n"
+    << Indent1 << "{\n"
+    << Indent2 << "std::string cmd;\n"
+    << Indent2 << "std::vector<std::string> vec;\n";
+
+  // cmd_line is either a string or a 'case' construct.
+  if (typeid(*P.CmdLine) == typeid(StringInit))
+    EmitCmdLineVecFill(P.CmdLine, P.Name, Version, Indent2, O);
+  else
+    EmitCaseConstructHandler(&InitPtrToDag(P.CmdLine), Indent2,
+                             EmitCmdLineVecFillCallback(Version, P.Name),
+                             true, OptDescs, O);
 
   // For every understood option, emit handling code.
   for (ToolOptionDescriptions::const_iterator B = P.OptDescs.begin(),
         E = P.OptDescs.end(); B != E; ++B) {
     const ToolOptionDescription& val = B->second;
-    EmitOptionPropertyHandlingCode(P, val, O);
+    EmitOptionPropertyHandlingCode(val, O);
   }
 
   // Handle the Sink property.
@@ -758,25 +1270,28 @@ void EmitGenerateActionMethod (const ToolProperties& P, bool V, std::ostream& O)
       << Indent2 << "}\n";
   }
 
-  O << Indent2 << "return Action(\"" << P.CmdLine.at(0) << "\", vec);\n"
+  O << Indent2 << "return Action(cmd, vec);\n"
     << Indent1 << "}\n\n";
 }
 
 /// EmitGenerateActionMethods - Emit two GenerateAction() methods for
 /// a given Tool class.
-void EmitGenerateActionMethods (const ToolProperties& P, std::ostream& O) {
-
+void EmitGenerateActionMethods (const ToolProperties& P,
+                                const GlobalOptionDescriptions& OptDescs,
+                                std::ostream& O) {
   if (!P.isJoin())
     O << Indent1 << "Action GenerateAction(const PathVector& inFiles,\n"
-      << Indent2 << "const llvm::sys::Path& outFile) const\n"
+      << Indent2 << "const llvm::sys::Path& outFile,\n"
+      << Indent2 << "const InputLanguagesSet& InLangs,\n"
+      << Indent2 << "const LanguageMap& LangMap) const\n"
       << Indent1 << "{\n"
       << Indent2 << "throw std::runtime_error(\"" << P.Name
       << " is not a Join tool!\");\n"
       << Indent1 << "}\n\n";
   else
-    EmitGenerateActionMethod(P, true, O);
+    EmitGenerateActionMethod(P, OptDescs, true, O);
 
-  EmitGenerateActionMethod(P, false, O);
+  EmitGenerateActionMethod(P, OptDescs, false, O);
 }
 
 /// EmitIsLastMethod - Emit the IsLast() method for a given Tool
@@ -802,8 +1317,8 @@ void EmitIsLastMethod (const ToolProperties& P, std::ostream& O) {
 /// EmitInOutLanguageMethods - Emit the [Input,Output]Language()
 /// methods for a given Tool class.
 void EmitInOutLanguageMethods (const ToolProperties& P, std::ostream& O) {
-  O << Indent1 << "const char* InputLanguage() const {\n"
-    << Indent2 << "return \"" << P.InLanguage << "\";\n"
+  O << Indent1 << "const char** InputLanguages() const {\n"
+    << Indent2 << "return InputLanguages_;\n"
     << Indent1 << "}\n\n";
 
   O << Indent1 << "const char* OutputLanguage() const {\n"
@@ -815,7 +1330,22 @@ void EmitInOutLanguageMethods (const ToolProperties& P, std::ostream& O) {
 /// given Tool class.
 void EmitOutputSuffixMethod (const ToolProperties& P, std::ostream& O) {
   O << Indent1 << "const char* OutputSuffix() const {\n"
-    << Indent2 << "return \"" << P.OutputSuffix << "\";\n"
+    << Indent2 << "const char* ret = \"" << P.OutputSuffix << "\";\n";
+
+  for (ToolOptionDescriptions::const_iterator B = P.OptDescs.begin(),
+         E = P.OptDescs.end(); B != E; ++B) {
+    const ToolOptionDescription& OptDesc = B->second;
+    for (OptionPropertyList::const_iterator B = OptDesc.Props.begin(),
+           E = OptDesc.Props.end(); B != E; ++B) {
+      const OptionProperty& OptProp = *B;
+      if (OptProp.first == OptionPropertyType::OutputSuffix) {
+        O << Indent2 << "if (" << OptDesc.GenVariableName() << ")\n"
+          << Indent3 << "ret = \"" << OptProp.second << "\";\n";
+      }
+    }
+  }
+
+  O << Indent2 << "return ret;\n"
     << Indent1 << "}\n\n";
 }
 
@@ -837,10 +1367,21 @@ void EmitIsJoinMethod (const ToolProperties& P, std::ostream& O) {
   O << Indent1 << "}\n\n";
 }
 
-/// EmitToolClassDefinition - Emit a Tool class definition.
-void EmitToolClassDefinition (const ToolProperties& P, std::ostream& O) {
+/// EmitStaticMemberDefinitions - Emit static member definitions for a
+/// given Tool class.
+void EmitStaticMemberDefinitions(const ToolProperties& P, std::ostream& O) {
+  O << "const char* " << P.Name << "::InputLanguages_[] = {";
+  for (StrVector::const_iterator B = P.InLanguage.begin(),
+         E = P.InLanguage.end(); B != E; ++B)
+    O << '\"' << *B << "\", ";
+  O << "0};\n\n";
+}
 
-  if(P.Name == "root")
+/// EmitToolClassDefinition - Emit a Tool class definition.
+void EmitToolClassDefinition (const ToolProperties& P,
+                              const GlobalOptionDescriptions& OptDescs,
+                              std::ostream& O) {
+  if (P.Name == "root")
     return;
 
   // Header
@@ -849,17 +1390,23 @@ void EmitToolClassDefinition (const ToolProperties& P, std::ostream& O) {
     O << "JoinTool";
   else
     O << "Tool";
-  O << " {\npublic:\n";
 
+  O << "{\nprivate:\n"
+    << Indent1 << "static const char* InputLanguages_[];\n\n";
+
+  O << "public:\n";
   EmitNameMethod(P, O);
   EmitInOutLanguageMethods(P, O);
   EmitOutputSuffixMethod(P, O);
   EmitIsJoinMethod(P, O);
-  EmitGenerateActionMethods(P, O);
+  EmitGenerateActionMethods(P, OptDescs, O);
   EmitIsLastMethod(P, O);
 
   // Close class definition
-  O << "};\n\n";
+  O << "};\n";
+
+  EmitStaticMemberDefinitions(P, O);
+
 }
 
 /// EmitOptionDescriptions - Iterate over a list of option
@@ -867,11 +1414,18 @@ void EmitToolClassDefinition (const ToolProperties& P, std::ostream& O) {
 void EmitOptionDescriptions (const GlobalOptionDescriptions& descs,
                              std::ostream& O)
 {
-  // Emit static cl::Option variables
+  std::vector<GlobalOptionDescription> Aliases;
+
+  // Emit static cl::Option variables.
   for (GlobalOptionDescriptions::const_iterator B = descs.begin(),
          E = descs.end(); B!=E; ++B) {
     const GlobalOptionDescription& val = B->second;
 
+    if (val.Type == OptionType::Alias) {
+      Aliases.push_back(val);
+      continue;
+    }
+
     O << val.GenTypeDeclaration() << ' '
       << val.GenVariableName()
       << "(\"" << val.Name << '\"';
@@ -890,9 +1444,43 @@ void EmitOptionDescriptions (const GlobalOptionDescriptions& descs,
       }
     }
 
-    O << ", cl::desc(\"" << val.Help << "\"));\n";
+    if (val.isReallyHidden() || val.isHidden()) {
+      if (val.isRequired())
+        O << " |";
+      else
+        O << ",";
+      if (val.isReallyHidden())
+        O << " cl::ReallyHidden";
+      else
+        O << " cl::Hidden";
+    }
+
+    if (!val.Help.empty())
+      O << ", cl::desc(\"" << val.Help << "\")";
+
+    O << ");\n";
+  }
+
+  // Emit the aliases (they should go after all the 'proper' options).
+  for (std::vector<GlobalOptionDescription>::const_iterator
+         B = Aliases.begin(), E = Aliases.end(); B != E; ++B) {
+    const GlobalOptionDescription& val = *B;
+
+    O << val.GenTypeDeclaration() << ' '
+      << val.GenVariableName()
+      << "(\"" << val.Name << '\"';
+
+    GlobalOptionDescriptions::container_type
+      ::const_iterator F = descs.Descriptions.find(val.Help);
+    if (F != descs.Descriptions.end())
+      O << ", cl::aliasopt(" << F->second.GenVariableName() << ")";
+    else
+      throw val.Name + ": alias to an unknown option!";
+
+    O << ", cl::desc(\"" << "An alias for -" + val.Help  << "\"));\n";
   }
 
+  // Emit the sink option.
   if (descs.HasSink)
     O << "cl::list<std::string> " << SinkOptionName << "(cl::Sink);\n";
 
@@ -902,175 +1490,108 @@ void EmitOptionDescriptions (const GlobalOptionDescriptions& descs,
 /// EmitPopulateLanguageMap - Emit the PopulateLanguageMap() function.
 void EmitPopulateLanguageMap (const RecordKeeper& Records, std::ostream& O)
 {
+  // Generate code
+  O << "namespace {\n\n";
+  O << "void PopulateLanguageMapLocal(LanguageMap& langMap) {\n";
+
   // Get the relevant field out of RecordKeeper
-  Record* LangMapRecord = Records.getDef("LanguageMap");
-  if (!LangMapRecord)
-    throw std::string("Language map definition not found!");
+  const Record* LangMapRecord = Records.getDef("LanguageMap");
 
-  ListInit* LangsToSuffixesList = LangMapRecord->getValueAsListInit("map");
-  if (!LangsToSuffixesList)
-    throw std::string("Error in the language map definition!");
+  // It is allowed for a plugin to have no language map.
+  if (LangMapRecord) {
 
-  // Generate code
-  O << "void llvmc::PopulateLanguageMap(LanguageMap& language_map) {\n";
+    ListInit* LangsToSuffixesList = LangMapRecord->getValueAsListInit("map");
+    if (!LangsToSuffixesList)
+      throw std::string("Error in the language map definition!");
 
-  for (unsigned i = 0; i < LangsToSuffixesList->size(); ++i) {
-    Record* LangToSuffixes = LangsToSuffixesList->getElementAsRecord(i);
+    for (unsigned i = 0; i < LangsToSuffixesList->size(); ++i) {
+      const Record* LangToSuffixes = LangsToSuffixesList->getElementAsRecord(i);
 
-    const std::string& Lang = LangToSuffixes->getValueAsString("lang");
-    const ListInit* Suffixes = LangToSuffixes->getValueAsListInit("suffixes");
+      const std::string& Lang = LangToSuffixes->getValueAsString("lang");
+      const ListInit* Suffixes = LangToSuffixes->getValueAsListInit("suffixes");
 
-    for (unsigned i = 0; i < Suffixes->size(); ++i)
-      O << Indent1 << "language_map[\""
-        << InitPtrToString(Suffixes->getElement(i))
-        << "\"] = \"" << Lang << "\";\n";
+      for (unsigned i = 0; i < Suffixes->size(); ++i)
+        O << Indent1 << "langMap[\""
+          << InitPtrToString(Suffixes->getElement(i))
+          << "\"] = \"" << Lang << "\";\n";
+    }
   }
 
-  O << "}\n\n";
+  O << "}\n\n}\n\n";
 }
 
 /// FillInToolToLang - Fills in two tables that map tool names to
 /// (input, output) languages.  Used by the typechecker.
 void FillInToolToLang (const ToolPropertiesList& TPList,
-                       StringMap<std::string>& ToolToInLang,
+                       StringMap<StringSet<> >& ToolToInLang,
                        StringMap<std::string>& ToolToOutLang) {
   for (ToolPropertiesList::const_iterator B = TPList.begin(), E = TPList.end();
        B != E; ++B) {
     const ToolProperties& P = *(*B);
-    ToolToInLang[P.Name] = P.InLanguage;
+    for (StrVector::const_iterator B = P.InLanguage.begin(),
+           E = P.InLanguage.end(); B != E; ++B)
+      ToolToInLang[P.Name].insert(*B);
     ToolToOutLang[P.Name] = P.OutLanguage;
   }
 }
 
 /// TypecheckGraph - Check that names for output and input languages
-/// on all edges do match.
-// TOFIX: check for cycles.
-// TOFIX: check for multiple default edges.
-void TypecheckGraph (Record* CompilationGraph,
+/// on all edges do match. This doesn't do much when the information
+/// about the whole graph is not available (i.e. when compiling most
+/// plugins).
+void TypecheckGraph (const RecordVector& EdgeVector,
                      const ToolPropertiesList& TPList) {
-  StringMap<std::string> ToolToInLang;
+  StringMap<StringSet<> > ToolToInLang;
   StringMap<std::string> ToolToOutLang;
 
   FillInToolToLang(TPList, ToolToInLang, ToolToOutLang);
-  ListInit* edges = CompilationGraph->getValueAsListInit("edges");
-  StringMap<std::string>::iterator IAE = ToolToInLang.end();
-  StringMap<std::string>::iterator IBE = ToolToOutLang.end();
-
-  for (unsigned i = 0; i < edges->size(); ++i) {
-    Record* Edge = edges->getElementAsRecord(i);
-    Record* A = Edge->getValueAsDef("a");
-    Record* B = Edge->getValueAsDef("b");
-    StringMap<std::string>::iterator IA = ToolToOutLang.find(A->getName());
-    StringMap<std::string>::iterator IB = ToolToInLang.find(B->getName());
-    if(IA == IAE)
-      throw A->getName() + ": no such tool!";
-    if(IB == IBE)
-      throw B->getName() + ": no such tool!";
-    if(A->getName() != "root" && IA->second != IB->second)
-      throw "Edge " + A->getName() + "->" + B->getName()
-        + ": output->input language mismatch";
-    if(B->getName() == "root")
-      throw std::string("Edges back to the root are not allowed!");
-  }
-}
-
-/// EmitEdgePropertyTest1Arg - Helper function used by
-/// EmitEdgePropertyTest.
-bool EmitEdgePropertyTest1Arg(const std::string& PropName,
-                              const DagInit& Prop,
-                              const GlobalOptionDescriptions& OptDescs,
-                              std::ostream& O) {
-  checkNumberOfArguments(&Prop, 1);
-  const std::string& OptName = InitPtrToString(Prop.getArg(0));
-  if (PropName == "switch_on") {
-    const GlobalOptionDescription& OptDesc = OptDescs.FindOption(OptName);
-    if (OptDesc.Type != OptionType::Switch)
-      throw OptName + ": incorrect option type!";
-    O << OptDesc.GenVariableName();
-    return true;
-  } else if (PropName == "if_input_languages_contain") {
-    O << "InLangs.count(\"" << OptName << "\") != 0";
-    return true;
-  }
-
-  return false;
-}
-
-/// EmitEdgePropertyTest2Args - Helper function used by
-/// EmitEdgePropertyTest.
-bool EmitEdgePropertyTest2Args(const std::string& PropName,
-                               const DagInit& Prop,
-                               const GlobalOptionDescriptions& OptDescs,
-                               std::ostream& O) {
-  checkNumberOfArguments(&Prop, 2);
-  const std::string& OptName = InitPtrToString(Prop.getArg(0));
-  const std::string& OptArg = InitPtrToString(Prop.getArg(1));
-  const GlobalOptionDescription& OptDesc = OptDescs.FindOption(OptName);
+  StringMap<std::string>::iterator IAE = ToolToOutLang.end();
+  StringMap<StringSet<> >::iterator IBE = ToolToInLang.end();
+
+  for (RecordVector::const_iterator B = EdgeVector.begin(),
+         E = EdgeVector.end(); B != E; ++B) {
+    const Record* Edge = *B;
+    const std::string& A = Edge->getValueAsString("a");
+    const std::string& B = Edge->getValueAsString("b");
+    StringMap<std::string>::iterator IA = ToolToOutLang.find(A);
+    StringMap<StringSet<> >::iterator IB = ToolToInLang.find(B);
+
+    if (A != "root") {
+      if (IA != IAE && IB != IBE && IB->second.count(IA->second) == 0)
+        throw "Edge " + A + "->" + B
+          + ": output->input language mismatch";
+    }
 
-  if (PropName == "parameter_equals") {
-    if (OptDesc.Type != OptionType::Parameter
-        && OptDesc.Type != OptionType::Prefix)
-      throw OptName + ": incorrect option type!";
-    O << OptDesc.GenVariableName() << " == \"" << OptArg << "\"";
-    return true;
-  }
-  else if (PropName == "element_in_list") {
-    if (OptDesc.Type != OptionType::ParameterList
-        && OptDesc.Type != OptionType::PrefixList)
-      throw OptName + ": incorrect option type!";
-    const std::string& VarName = OptDesc.GenVariableName();
-    O << "std::find(" << VarName << ".begin(),\n"
-      << Indent3 << VarName << ".end(), \""
-      << OptArg << "\") != " << VarName << ".end()";
-    return true;
+    if (B == "root")
+      throw std::string("Edges back to the root are not allowed!");
   }
-
-  return false;
 }
 
-// Forward declaration.
-void EmitEdgePropertyTest(const DagInit& Prop,
-                          const GlobalOptionDescriptions& OptDescs,
-                          std::ostream& O);
-
-/// EmitLogicalOperationTest - Helper function used by
-/// EmitEdgePropertyTest.
-void EmitLogicalOperationTest(const DagInit& Prop, const char* LogicOp,
-                              const GlobalOptionDescriptions& OptDescs,
-                              std::ostream& O) {
-  O << '(';
-  for (unsigned j = 0, NumArgs = Prop.getNumArgs(); j < NumArgs; ++j) {
-    const DagInit& InnerProp = InitPtrToDagInitRef(Prop.getArg(j));
-    EmitEdgePropertyTest(InnerProp, OptDescs, O);
-    if (j != NumArgs - 1)
-      O << ")\n" << Indent3 << ' ' << LogicOp << " (";
-    else
-      O << ')';
-  }
-}
+/// IncDecWeight - Helper function passed to EmitCaseConstructHandler()
+/// by EmitEdgeClass().
+void IncDecWeight (const Init* i, const char* IndentLevel,
+                   std::ostream& O) {
+  const DagInit& d = InitPtrToDag(i);
+  const std::string& OpName = d.getOperator()->getAsString();
 
-/// EmitEdgePropertyTest - Helper function used by EmitEdgeClass.
-void EmitEdgePropertyTest(const DagInit& Prop,
-                          const GlobalOptionDescriptions& OptDescs,
-                          std::ostream& O) {
-  const std::string& PropName = Prop.getOperator()->getAsString();
+  if (OpName == "inc_weight")
+    O << IndentLevel << Indent1 << "ret += ";
+  else if (OpName == "dec_weight")
+    O << IndentLevel << Indent1 << "ret -= ";
+  else
+    throw "Unknown operator in edge properties list: " + OpName + '!';
 
-  if (PropName == "and")
-    EmitLogicalOperationTest(Prop, "&&", OptDescs, O);
-  else if (PropName == "or")
-    EmitLogicalOperationTest(Prop, "||", OptDescs, O);
-  else if (EmitEdgePropertyTest1Arg(PropName, Prop, OptDescs, O))
-    return;
-  else if (EmitEdgePropertyTest2Args(PropName, Prop, OptDescs, O))
-    return;
+  if (d.getNumArgs() > 0)
+    O << InitPtrToInt(d.getArg(0)) << ";\n";
   else
-    throw PropName + ": unknown edge property!";
+    O << "2;\n";
+
 }
 
 /// EmitEdgeClass - Emit a single Edge# class.
-void EmitEdgeClass(unsigned N, const std::string& Target,
-                   ListInit* Props, const GlobalOptionDescriptions& OptDescs,
-                   std::ostream& O) {
+void EmitEdgeClass (unsigned N, const std::string& Target,
+                    DagInit* Case, const GlobalOptionDescriptions& OptDescs,
+                    std::ostream& O) {
 
   // Class constructor.
   O << "class Edge" << N << ": public Edge {\n"
@@ -1082,139 +1603,313 @@ void EmitEdgeClass(unsigned N, const std::string& Target,
     << Indent1 << "unsigned Weight(const InputLanguagesSet& InLangs) const {\n"
     << Indent2 << "unsigned ret = 0;\n";
 
-  // Emit tests for every edge property.
-  for (size_t i = 0, PropsSize = Props->size(); i < PropsSize; ++i) {
-    const DagInit& Prop = InitPtrToDagInitRef(Props->getElement(i));
-    const std::string& PropName = Prop.getOperator()->getAsString();
-    unsigned N = 2;
-
-    O << Indent2 << "if (";
-
-    if (PropName == "weight") {
-      checkNumberOfArguments(&Prop, 2);
-      N = InitPtrToInt(Prop.getArg(0));
-      const DagInit& InnerProp = InitPtrToDagInitRef(Prop.getArg(1));
-      EmitEdgePropertyTest(InnerProp, OptDescs, O);
-    }
-    else {
-      EmitEdgePropertyTest(Prop, OptDescs, O);
-    }
-
-    O << ")\n" << Indent3 << "ret += " << N << ";\n";
-  }
+  // Handle the 'case' construct.
+  EmitCaseConstructHandler(Case, Indent2, IncDecWeight, false, OptDescs, O);
 
   O << Indent2 << "return ret;\n"
     << Indent1 << "};\n\n};\n\n";
 }
 
-// Emit Edge* classes that represent graph edges.
-void EmitEdgeClasses (Record* CompilationGraph,
+/// EmitEdgeClasses - Emit Edge* classes that represent graph edges.
+void EmitEdgeClasses (const RecordVector& EdgeVector,
                       const GlobalOptionDescriptions& OptDescs,
                       std::ostream& O) {
-  ListInit* edges = CompilationGraph->getValueAsListInit("edges");
-
-  for (unsigned i = 0; i < edges->size(); ++i) {
-    Record* Edge = edges->getElementAsRecord(i);
-    Record* B = Edge->getValueAsDef("b");
-    ListInit* Props = Edge->getValueAsListInit("props");
-
-    if (Props->empty())
-      continue;
-
-    EmitEdgeClass(i, B->getName(), Props, OptDescs, O);
+  int i = 0;
+  for (RecordVector::const_iterator B = EdgeVector.begin(),
+         E = EdgeVector.end(); B != E; ++B) {
+    const Record* Edge = *B;
+    const std::string& B = Edge->getValueAsString("b");
+    DagInit* Weight = Edge->getValueAsDag("weight");
+
+    if (!isDagEmpty(Weight))
+      EmitEdgeClass(i, B, Weight, OptDescs, O);
+    ++i;
   }
 }
 
 /// EmitPopulateCompilationGraph - Emit the PopulateCompilationGraph()
 /// function.
-void EmitPopulateCompilationGraph (Record* CompilationGraph,
+void EmitPopulateCompilationGraph (const RecordVector& EdgeVector,
+                                   const ToolPropertiesList& ToolProps,
                                    std::ostream& O)
 {
-  ListInit* edges = CompilationGraph->getValueAsListInit("edges");
-
-  // Generate code
-  O << "void llvmc::PopulateCompilationGraph(CompilationGraph& G) {\n"
-    << Indent1 << "PopulateLanguageMap(G.ExtsToLangs);\n\n";
-
-  // Insert vertices
+  O << "namespace {\n\n";
+  O << "void PopulateCompilationGraphLocal(CompilationGraph& G) {\n";
 
-  RecordVector Tools = Records.getAllDerivedDefinitions("Tool");
-  if (Tools.empty())
-    throw std::string("No tool definitions found!");
-
-  for (RecordVector::iterator B = Tools.begin(), E = Tools.end(); B != E; ++B) {
-    const std::string& Name = (*B)->getName();
-    if(Name != "root")
-      O << Indent1 << "G.insertNode(new "
-        << Name << "());\n";
-  }
+  for (ToolPropertiesList::const_iterator B = ToolProps.begin(),
+         E = ToolProps.end(); B != E; ++B)
+    O << Indent1 << "G.insertNode(new " << (*B)->Name << "());\n";
 
   O << '\n';
 
-  // Insert edges
-  for (unsigned i = 0; i < edges->size(); ++i) {
-    Record* Edge = edges->getElementAsRecord(i);
-    Record* A = Edge->getValueAsDef("a");
-    Record* B = Edge->getValueAsDef("b");
-    ListInit* Props = Edge->getValueAsListInit("props");
+  // Insert edges.
 
-    O << Indent1 << "G.insertEdge(\"" << A->getName() << "\", ";
+  int i = 0;
+  for (RecordVector::const_iterator B = EdgeVector.begin(),
+         E = EdgeVector.end(); B != E; ++B) {
+    const Record* Edge = *B;
+    const std::string& A = Edge->getValueAsString("a");
+    const std::string& B = Edge->getValueAsString("b");
+    DagInit* Weight = Edge->getValueAsDag("weight");
 
-    if (Props->empty())
-      O << "new SimpleEdge(\"" << B->getName() << "\")";
+    O << Indent1 << "G.insertEdge(\"" << A << "\", ";
+
+    if (isDagEmpty(Weight))
+      O << "new SimpleEdge(\"" << B << "\")";
     else
       O << "new Edge" << i << "()";
 
     O << ");\n";
+    ++i;
+  }
+
+  O << "}\n\n}\n\n";
+}
+
+/// ExtractHookNames - Extract the hook names from all instances of
+/// $CALL(HookName) in the provided command line string. Helper
+/// function used by FillInHookNames().
+void ExtractHookNames(const Init* CmdLine, StrVector& HookNames) {
+  StrVector cmds;
+  llvm::SplitString(InitPtrToString(CmdLine), cmds);
+  for (StrVector::const_iterator B = cmds.begin(), E = cmds.end();
+       B != E; ++B) {
+    const std::string& cmd = *B;
+    if (cmd.find("$CALL(") == 0) {
+      if (cmd.size() == 6)
+        throw std::string("$CALL invocation: empty argument list!");
+      HookNames.push_back(std::string(cmd.begin() + 6,
+                                      cmd.begin() + cmd.find(")")));
+    }
+  }
+}
+
+/// ExtractHookNamesFromCaseConstruct - Extract hook names from the
+/// 'case' expression, handle nesting. Helper function used by
+/// FillInHookNames().
+void ExtractHookNamesFromCaseConstruct(Init* Case, StrVector& HookNames) {
+  const DagInit& d = InitPtrToDag(Case);
+  bool even = false;
+  for (DagInit::const_arg_iterator B = d.arg_begin(), E = d.arg_end();
+       B != E; ++B) {
+    Init* arg = *B;
+    if (even && dynamic_cast<DagInit*>(arg)
+        && static_cast<DagInit*>(arg)->getOperator()->getAsString() == "case")
+      ExtractHookNamesFromCaseConstruct(arg, HookNames);
+    else if (even)
+      ExtractHookNames(arg, HookNames);
+    even = !even;
   }
+}
+
+/// FillInHookNames - Actually extract the hook names from all command
+/// line strings. Helper function used by EmitHookDeclarations().
+void FillInHookNames(const ToolPropertiesList& TPList,
+                     StrVector& HookNames) {
+  // For all command lines:
+  for (ToolPropertiesList::const_iterator B = TPList.begin(),
+         E = TPList.end(); B != E; ++B) {
+    const ToolProperties& P = *(*B);
+    if (!P.CmdLine)
+      continue;
+    if (dynamic_cast<StringInit*>(P.CmdLine))
+      // This is a string.
+      ExtractHookNames(P.CmdLine, HookNames);
+    else
+      // This is a 'case' construct.
+      ExtractHookNamesFromCaseConstruct(P.CmdLine, HookNames);
+  }
+}
+
+/// EmitHookDeclarations - Parse CmdLine fields of all the tool
+/// property records and emit hook function declaration for each
+/// instance of $CALL(HookName).
+void EmitHookDeclarations(const ToolPropertiesList& ToolProps,
+                          std::ostream& O) {
+  StrVector HookNames;
+  FillInHookNames(ToolProps, HookNames);
+  if (HookNames.empty())
+    return;
+  std::sort(HookNames.begin(), HookNames.end());
+  StrVector::const_iterator E = std::unique(HookNames.begin(), HookNames.end());
+
+  O << "namespace hooks {\n";
+  for (StrVector::const_iterator B = HookNames.begin(); B != E; ++B)
+    O << Indent1 << "std::string " << *B << "();\n";
 
   O << "}\n\n";
 }
 
+/// EmitRegisterPlugin - Emit code to register this plugin.
+void EmitRegisterPlugin(int Priority, std::ostream& O) {
+  O << "namespace {\n\n"
+    << "struct Plugin : public llvmc::BasePlugin {\n\n"
+    << Indent1 << "int Priority() const { return " << Priority << "; }\n\n"
+    << Indent1 << "void PopulateLanguageMap(LanguageMap& langMap) const\n"
+    << Indent1 << "{ PopulateLanguageMapLocal(langMap); }\n\n"
+    << Indent1
+    << "void PopulateCompilationGraph(CompilationGraph& graph) const\n"
+    << Indent1 << "{ PopulateCompilationGraphLocal(graph); }\n"
+    << "};\n\n"
+
+    << "static llvmc::RegisterPlugin<Plugin> RP;\n\n}\n\n";
+}
+
+/// EmitIncludes - Emit necessary #include directives and some
+/// additional declarations.
+void EmitIncludes(std::ostream& O) {
+  O << "#include \"llvm/CompilerDriver/CompilationGraph.h\"\n"
+    << "#include \"llvm/CompilerDriver/Plugin.h\"\n"
+    << "#include \"llvm/CompilerDriver/Tool.h\"\n\n"
+
+    << "#include \"llvm/ADT/StringExtras.h\"\n"
+    << "#include \"llvm/Support/CommandLine.h\"\n\n"
+
+    << "#include <cstdlib>\n"
+    << "#include <stdexcept>\n\n"
+
+    << "using namespace llvm;\n"
+    << "using namespace llvmc;\n\n"
+
+    << "extern cl::opt<std::string> OutputFilename;\n\n"
+
+    << "inline const char* checkCString(const char* s)\n"
+    << "{ return s == NULL ? \"\" : s; }\n\n";
+}
+
+/// NotInGraph - Helper function object for FilterNotInGraph.
+struct NotInGraph {
+private:
+  const llvm::StringSet<>& ToolsInGraph_;
+
+public:
+  NotInGraph(const llvm::StringSet<>& ToolsInGraph)
+  : ToolsInGraph_(ToolsInGraph)
+  {}
+
+  bool operator()(const IntrusiveRefCntPtr<ToolProperties>& x) {
+    return (ToolsInGraph_.count(x->Name) == 0);
+  }
+};
+
+/// FilterNotInGraph - Filter out from ToolProps all Tools not
+/// mentioned in the compilation graph definition.
+void FilterNotInGraph (const RecordVector& EdgeVector,
+                       ToolPropertiesList& ToolProps) {
+
+  // List all tools mentioned in the graph.
+  llvm::StringSet<> ToolsInGraph;
+
+  for (RecordVector::const_iterator B = EdgeVector.begin(),
+         E = EdgeVector.end(); B != E; ++B) {
+
+    const Record* Edge = *B;
+    const std::string& A = Edge->getValueAsString("a");
+    const std::string& B = Edge->getValueAsString("b");
+
+    if (A != "root")
+      ToolsInGraph.insert(A);
+    ToolsInGraph.insert(B);
+  }
+
+  // Filter ToolPropertiesList.
+  ToolPropertiesList::iterator new_end =
+    std::remove_if(ToolProps.begin(), ToolProps.end(),
+                   NotInGraph(ToolsInGraph));
+  ToolProps.erase(new_end, ToolProps.end());
+}
+
+/// CalculatePriority - Calculate the priority of this plugin.
+int CalculatePriority(RecordVector::const_iterator B,
+                      RecordVector::const_iterator E) {
+  int total = 0;
+  for (; B!=E; ++B) {
+    total += static_cast<int>((*B)->getValueAsInt("priority"));
+  }
+  return total;
+}
+
+/// FillInEdgeVector - Merge all compilation graph definitions into
+/// one single edge list.
+void FillInEdgeVector(RecordVector::const_iterator B,
+                      RecordVector::const_iterator E, RecordVector& Out) {
+  for (; B != E; ++B) {
+    const ListInit* edges = (*B)->getValueAsListInit("edges");
+
+    for (unsigned i = 0; i < edges->size(); ++i)
+      Out.push_back(edges->getElementAsRecord(i));
+  }
+}
 
 // End of anonymous namespace
 }
 
 /// run - The back-end entry point.
 void LLVMCConfigurationEmitter::run (std::ostream &O) {
+  try {
 
   // Emit file header.
   EmitSourceFileHeader("LLVMC Configuration Library", O);
+  EmitIncludes(O);
 
-  // Get a list of all defined Tools.
+  // Collect tool properties.
   RecordVector Tools = Records.getAllDerivedDefinitions("Tool");
-  if (Tools.empty())
-    throw std::string("No tool definitions found!");
+  ToolPropertiesList ToolProps;
+  GlobalOptionDescriptions OptDescs;
+  CollectToolProperties(Tools.begin(), Tools.end(), ToolProps, OptDescs);
+
+  // Collect option properties.
+  const RecordVector& OptionLists =
+    Records.getAllDerivedDefinitions("OptionList");
+  CollectPropertiesFromOptionLists(OptionLists.begin(), OptionLists.end(),
+                                   OptDescs);
+
+  // Collect compilation graph edges.
+  const RecordVector& CompilationGraphs =
+    Records.getAllDerivedDefinitions("CompilationGraph");
+  RecordVector EdgeVector;
+  FillInEdgeVector(CompilationGraphs.begin(), CompilationGraphs.end(),
+                   EdgeVector);
+
+  // Filter out all tools not mentioned in the compilation graph.
+  FilterNotInGraph(EdgeVector, ToolProps);
 
-  // Gather information from the Tool description dags.
-  ToolPropertiesList tool_props;
-  GlobalOptionDescriptions opt_descs;
-  CollectToolProperties(Tools.begin(), Tools.end(), tool_props, opt_descs);
+  // Typecheck the compilation graph.
+  TypecheckGraph(EdgeVector, ToolProps);
+
+  // Check that there are no options without side effects (specified
+  // only in the OptionList).
+  CheckForSuperfluousOptions(ToolProps, OptDescs);
 
   // Emit global option registration code.
-  EmitOptionDescriptions(opt_descs, O);
+  EmitOptionDescriptions(OptDescs, O);
+
+  // Emit hook declarations.
+  EmitHookDeclarations(ToolProps, O);
 
   // Emit PopulateLanguageMap() function
   // (a language map maps from file extensions to language names).
   EmitPopulateLanguageMap(Records, O);
 
   // Emit Tool classes.
-  for (ToolPropertiesList::const_iterator B = tool_props.begin(),
-         E = tool_props.end(); B!=E; ++B)
-    EmitToolClassDefinition(*(*B), O);
-
-  Record* CompilationGraphRecord = Records.getDef("CompilationGraph");
-  if (!CompilationGraphRecord)
-    throw std::string("Compilation graph description not found!");
-
-  // Typecheck the compilation graph.
-  TypecheckGraph(CompilationGraphRecord, tool_props);
+  for (ToolPropertiesList::const_iterator B = ToolProps.begin(),
+         E = ToolProps.end(); B!=E; ++B)
+    EmitToolClassDefinition(*(*B), OptDescs, O);
 
   // Emit Edge# classes.
-  EmitEdgeClasses(CompilationGraphRecord, opt_descs, O);
+  EmitEdgeClasses(EdgeVector, OptDescs, O);
 
   // Emit PopulateCompilationGraph() function.
-  EmitPopulateCompilationGraph(CompilationGraphRecord, O);
+  EmitPopulateCompilationGraph(EdgeVector, ToolProps, O);
+
+  // Emit code for plugin registration.
+  const RecordVector& Priorities =
+    Records.getAllDerivedDefinitions("PluginPriority");
+  EmitRegisterPlugin(CalculatePriority(Priorities.begin(),
+                                       Priorities.end()), O);
 
   // EOF
+  } catch (std::exception& Error) {
+    throw Error.what() + std::string(" - usually this means a syntax error.");
+  }
 }