diff --git a/clang/include/clang/Frontend/CompilerInvocation.h b/clang/include/clang/Frontend/CompilerInvocation.h
index 33234ec89873..9d068c523c69 100644
--- a/clang/include/clang/Frontend/CompilerInvocation.h
+++ b/clang/include/clang/Frontend/CompilerInvocation.h
@@ -20,8 +20,14 @@
 #include "clang/Frontend/HeaderSearchOptions.h"
 #include "clang/Frontend/PreprocessorOptions.h"
 #include "clang/Frontend/PreprocessorOutputOptions.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringMap.h"
 #include <string>
+#include <vector>
+
+namespace llvm {
+  template<typename T> class SmallVectorImpl;
+}
 
 namespace clang {
 
@@ -65,6 +71,23 @@ class CompilerInvocation {
 public:
   CompilerInvocation() {}
 
+  /// @name Utility Methods
+  /// @{
+
+  /// CreateFromArgs - Create a compiler invocation from a list of input
+  /// options.
+  ///
+  /// FIXME: Documenting error behavior.
+  ///
+  /// \param Res [out] - The resulting invocation.
+  /// \param Args - The input argument strings.
+  static void CreateFromArgs(CompilerInvocation &Res,
+                            const llvm::SmallVectorImpl<llvm::StringRef> &Args);
+
+  /// toArgs - Convert the CompilerInvocation to a list of strings suitable for
+  /// passing to CreateFromArgs.
+  void toArgs(std::vector<std::string> &Res);
+
   /// @}
   /// @name Option Subgroups
   /// @{
diff --git a/clang/lib/Frontend/CMakeLists.txt b/clang/lib/Frontend/CMakeLists.txt
index 9f05919d544e..3f0f43099c69 100644
--- a/clang/lib/Frontend/CMakeLists.txt
+++ b/clang/lib/Frontend/CMakeLists.txt
@@ -7,6 +7,7 @@ add_clang_library(clangFrontend
   Backend.cpp
   CacheTokens.cpp
   CompilerInstance.cpp
+  CompilerInvocation.cpp
   DeclXML.cpp
   DependencyFile.cpp
   DiagChecker.cpp
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
new file mode 100644
index 000000000000..c8e52fe7cb6c
--- /dev/null
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -0,0 +1,547 @@
+//===--- CompilerInvocation.cpp -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/CompilerInvocation.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/ErrorHandling.h"
+using namespace clang;
+
+void CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
+                           const llvm::SmallVectorImpl<llvm::StringRef> &Args) {
+  llvm::llvm_report_error("FIXME: Not yet implemented!");
+}
+
+static const char *getAnalysisName(Analyses Kind) {
+  switch (Kind) {
+  default:
+    llvm::llvm_unreachable("Unknown analysis store!");
+#define ANALYSIS(NAME, CMDFLAG, DESC, SCOPE)\
+  case NAME: return CMDFLAG;
+#include "clang/Frontend/Analyses.def"
+  }
+}
+
+static const char *getAnalysisStoreName(AnalysisStores Kind) {
+  switch (Kind) {
+  default:
+    llvm::llvm_unreachable("Unknown analysis store!");
+#define ANALYSIS_STORE(NAME, CMDFLAG, DESC, CREATFN) \
+  case NAME##Model: return CMDFLAG;
+#include "clang/Frontend/Analyses.def"
+  }
+}
+
+static const char *getAnalysisConstraintName(AnalysisConstraints Kind) {
+  switch (Kind) {
+  default:
+    llvm::llvm_unreachable("Unknown analysis constraints!");
+#define ANALYSIS_CONSTRAINTS(NAME, CMDFLAG, DESC, CREATFN) \
+  case NAME##Model: return CMDFLAG;
+#include "clang/Frontend/Analyses.def"
+  }
+}
+
+static const char *getAnalysisDiagClientName(AnalysisDiagClients Kind) {
+  switch (Kind) {
+  default:
+    llvm::llvm_unreachable("Unknown analysis client!");
+#define ANALYSIS_DIAGNOSTICS(NAME, CMDFLAG, DESC, CREATFN, AUTOCREATE) \
+  case PD_##NAME: return CMDFLAG;
+#include "clang/Frontend/Analyses.def"
+  }
+}
+
+static void AnalyzerOptsToArgs(const AnalyzerOptions &Opts,
+                               std::vector<std::string> &Res) {
+  for (unsigned i = 0, e = Opts.AnalysisList.size(); i != e; ++i)
+    Res.push_back(getAnalysisName(Opts.AnalysisList[i]));
+  if (Opts.AnalysisStoreOpt != BasicStoreModel) {
+    Res.push_back("-analyzer-store");
+    Res.push_back(getAnalysisStoreName(Opts.AnalysisStoreOpt));
+  }
+  if (Opts.AnalysisConstraintsOpt != RangeConstraintsModel) {
+    Res.push_back("-analyzer-constraints");
+    Res.push_back(getAnalysisConstraintName(Opts.AnalysisConstraintsOpt));
+  }
+  if (Opts.AnalysisDiagOpt != PD_HTML) {
+    Res.push_back("-analyzer-output");
+    Res.push_back(getAnalysisDiagClientName(Opts.AnalysisDiagOpt));
+  }
+  if (!Opts.AnalyzeSpecificFunction.empty()) {
+    Res.push_back("-analyze-function");
+    Res.push_back(Opts.AnalyzeSpecificFunction);
+  }
+  if (Opts.AnalyzeAll)
+    Res.push_back("-analyzer-opt-analyze-headers");
+  if (Opts.AnalyzerDisplayProgress)
+    Res.push_back("-analyzer-display-progress");
+  if (Opts.EagerlyAssume)
+    Res.push_back("-analyzer-eagerly-assume");
+  if (Opts.PurgeDead)
+    Res.push_back("-analyzer-purge-dead");
+  if (Opts.TrimGraph)
+    Res.push_back("-trim-egraph");
+  if (Opts.VisualizeEGDot)
+    Res.push_back("-analyzer-viz-egraph-graphviz");
+  if (Opts.VisualizeEGDot)
+    Res.push_back("-analyzer-viz-egraph-ubigraph");
+  if (Opts.EnableExperimentalChecks)
+    Res.push_back("-analyzer-experimental-checks");
+  if (Opts.EnableExperimentalInternalChecks)
+    Res.push_back("-analyzer-experimental-internal-checls");
+}
+
+static void CodeGenOptsToArgs(const CodeGenOptions &Opts,
+                              std::vector<std::string> &Res) {
+  if (Opts.DebugInfo)
+    Res.push_back("-g");
+  if (Opts.DisableLLVMOpts)
+    Res.push_back("-disable-llvm-optzns");
+  if (Opts.DisableRedZone)
+    Res.push_back("-disable-red-zone");
+  if (!Opts.MergeAllConstants)
+    Res.push_back("-fno-merge-all-constants");
+  // NoCommon is only derived.
+  if (Opts.NoImplicitFloat)
+    Res.push_back("-no-implicit-float");
+  if (Opts.OptimizeSize) {
+    assert(Opts.OptimizationLevel == 2 && "Invalid options!");
+    Res.push_back("-Os");
+  } else if (Opts.OptimizationLevel == 0)
+    Res.push_back("-O" + Opts.OptimizationLevel);
+  // SimplifyLibCalls is only derived.
+  // TimePasses is only derived.
+  // UnitAtATime is unused.
+  // UnrollLoops is only derived.
+  // VerifyModule is only derived.
+  // Inlining is only derived.
+}
+
+static void DependencyOutputOptsToArgs(const DependencyOutputOptions &Opts,
+                                       std::vector<std::string> &Res) {
+  if (Opts.IncludeSystemHeaders)
+    Res.push_back("-sys-header-deps");
+  if (Opts.UsePhonyTargets)
+    Res.push_back("-MP");
+  if (!Opts.OutputFile.empty()) {
+    Res.push_back("-dependency-file");
+    Res.push_back(Opts.OutputFile);
+  }
+  for (unsigned i = 0, e = Opts.Targets.size(); i != e; ++i) {
+    Res.push_back("-MT");
+    Res.push_back(Opts.Targets[i]);
+  }
+}
+
+static void DiagnosticOptsToArgs(const DiagnosticOptions &Opts,
+                                 std::vector<std::string> &Res) {
+  if (Opts.IgnoreWarnings)
+    Res.push_back("-w");
+  if (Opts.NoRewriteMacros)
+    Res.push_back("-Wno-rewrite-macros");
+  if (Opts.Pedantic)
+    Res.push_back("-pedantic");
+  if (Opts.PedanticErrors)
+    Res.push_back("-pedantic-errors");
+  if (!Opts.ShowColumn)
+    Res.push_back("-fno-show-column");
+  if (!Opts.ShowLocation)
+    Res.push_back("-fno-show-source-location");
+  if (!Opts.ShowCarets)
+    Res.push_back("-fno-caret-diagnostics");
+  if (!Opts.ShowFixits)
+    Res.push_back("-fno-diagnostics-fixit-info");
+  if (Opts.ShowSourceRanges)
+    Res.push_back("-fdiagnostics-print-source-range-info");
+  if (Opts.ShowColors)
+    Res.push_back("-fcolor-diagnostics");
+  if (Opts.VerifyDiagnostics)
+    Res.push_back("-verify");
+  if (Opts.ShowOptionNames)
+    Res.push_back("-fdiagnostics-show-option");
+  if (Opts.MessageLength) {
+    Res.push_back("-fmessage-length");
+    Res.push_back(llvm::utostr(Opts.MessageLength));
+  }
+  if (!Opts.DumpBuildInformation.empty()) {
+    Res.push_back("-dump-build-information");
+    Res.push_back(Opts.DumpBuildInformation);
+  }
+  for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i)
+    Res.push_back("-W" + Opts.Warnings[i]);
+}
+
+static const char *getInputKindName(FrontendOptions::InputKind Kind) {
+  switch (Kind) {
+  case FrontendOptions::IK_None: break;
+  case FrontendOptions::IK_AST: return "ast";
+  case FrontendOptions::IK_Asm: return "assembler-with-cpp";
+  case FrontendOptions::IK_C: return "c";
+  case FrontendOptions::IK_CXX: return "c++";
+  case FrontendOptions::IK_ObjC: return "objective-c";
+  case FrontendOptions::IK_ObjCXX: return "objective-c++";
+  case FrontendOptions::IK_OpenCL: return "cl";
+  case FrontendOptions::IK_PreprocessedC: return "cpp-output";
+  case FrontendOptions::IK_PreprocessedCXX: return "c++-cpp-output";
+  case FrontendOptions::IK_PreprocessedObjC: return "objective-c-cpp-output";
+  case FrontendOptions::IK_PreprocessedObjCXX: return "objective-c++-cpp-output";
+  }
+
+  llvm::llvm_unreachable("Unexpected language kind!");
+  return 0;
+}
+
+static const char *getActionName(frontend::ActionKind Kind) {
+  switch (Kind) {
+  case frontend::PluginAction:
+  case frontend::InheritanceView:
+    llvm::llvm_unreachable("Invalid kind!");
+
+  case frontend::ASTDump:                return "-ast-dump";
+  case frontend::ASTPrint:               return "-ast-print";
+  case frontend::ASTPrintXML:            return "-ast-print-xml";
+  case frontend::ASTView:                return "-ast-view";
+  case frontend::DumpRawTokens:          return "-dump-raw-tokens";
+  case frontend::DumpRecordLayouts:      return "-dump-record-layouts";
+  case frontend::DumpTokens:             return "-dump-tokens";
+  case frontend::EmitAssembly:           return "-S";
+  case frontend::EmitBC:                 return "-emit-llvm-bc";
+  case frontend::EmitHTML:               return "-emit-html";
+  case frontend::EmitLLVM:               return "-emit-llvm";
+  case frontend::EmitLLVMOnly:           return "-emit-llvm-only";
+  case frontend::FixIt:                  return "-fixit";
+  case frontend::GeneratePCH:            return "-emit-pch";
+  case frontend::GeneratePTH:            return "-emit-pth";
+  case frontend::ParseNoop:              return "-parse-noop";
+  case frontend::ParsePrintCallbacks:    return "-parse-print-callbacks";
+  case frontend::ParseSyntaxOnly:        return "-fsyntax-only";
+  case frontend::PrintDeclContext:       return "-print-decl-contexts";
+  case frontend::PrintPreprocessedInput: return "-E";
+  case frontend::RewriteBlocks:          return "-rewrite-blocks";
+  case frontend::RewriteMacros:          return "-rewrite-macros";
+  case frontend::RewriteObjC:            return "-rewrite-objc";
+  case frontend::RewriteTest:            return "-rewrite-test";
+  case frontend::RunAnalysis:            return "-analyze";
+  case frontend::RunPreprocessorOnly:    return "-Eonly";
+  }
+
+  llvm::llvm_unreachable("Unexpected language kind!");
+  return 0;
+}
+
+static void FrontendOptsToArgs(const FrontendOptions &Opts,
+                               std::vector<std::string> &Res) {
+  if (!Opts.DebugCodeCompletionPrinter)
+    Res.push_back("-code-completion-debug-printer=0");
+  if (Opts.DisableFree)
+    Res.push_back("-disable-free");
+  if (Opts.EmptyInputOnly)
+    Res.push_back("-empty-input-only");
+  if (Opts.RelocatablePCH)
+    Res.push_back("-relocatable-pch");
+  if (Opts.ShowMacrosInCodeCompletion)
+    Res.push_back("-code-completion-macros");
+  if (Opts.ShowStats)
+    Res.push_back("-stats");
+  if (Opts.ShowTimers)
+    Res.push_back("-ftime-report");
+
+  bool NeedLang = false;
+  for (unsigned i = 0, e = Opts.Inputs.size(); i != e; ++i)
+    if (FrontendOptions::getInputKindForExtension(Opts.Inputs[i].second) !=
+        Opts.Inputs[i].first)
+      NeedLang = true;
+  if (NeedLang) {
+    Res.push_back("-x");
+    Res.push_back(getInputKindName(Opts.Inputs[0].first));
+  }
+  for (unsigned i = 0, e = Opts.Inputs.size(); i != e; ++i) {
+    assert((!NeedLang || Opts.Inputs[i].first == Opts.Inputs[0].first) &&
+           "Unable to represent this input vector!");
+    Res.push_back(Opts.Inputs[i].second);
+  }
+
+  if (!Opts.OutputFile.empty()) {
+    Res.push_back("-o");
+    Res.push_back(Opts.OutputFile);
+  }
+  if (!Opts.ViewClassInheritance.empty()) {
+    Res.push_back("-cxx-inheritance-view");
+    Res.push_back(Opts.ViewClassInheritance);
+  }
+  for (unsigned i = 0, e = Opts.FixItLocations.size(); i != e; ++i) {
+    Res.push_back("-fixit-at");
+    Res.push_back(Opts.FixItLocations[i].FileName + ":" +
+                  llvm::utostr(Opts.FixItLocations[i].Line) + ":" +
+                  llvm::utostr(Opts.FixItLocations[i].Column));
+  }
+  if (!Opts.CodeCompletionAt.FileName.empty()) {
+    Res.push_back("-code-completion-at");
+    Res.push_back(Opts.CodeCompletionAt.FileName + ":" +
+                  llvm::utostr(Opts.CodeCompletionAt.Line) + ":" +
+                  llvm::utostr(Opts.CodeCompletionAt.Column));
+  }
+  if (Opts.ProgramAction != frontend::InheritanceView &&
+      Opts.ProgramAction != frontend::PluginAction)
+    Res.push_back(getActionName(Opts.ProgramAction));
+  if (!Opts.ActionName.empty()) {
+    Res.push_back("-plugin");
+    Res.push_back(Opts.ActionName);
+  }
+}
+
+static void HeaderSearchOptsToArgs(const HeaderSearchOptions &Opts,
+                                   std::vector<std::string> &Res) {
+  if (Opts.Sysroot.empty()) {
+    Res.push_back("-isysroot");
+    Res.push_back(Opts.Sysroot);
+  }
+
+  /// User specified include entries.
+  for (unsigned i = 0, e = Opts.UserEntries.size(); i != e; ++i) {
+    const HeaderSearchOptions::Entry &E = Opts.UserEntries[i];
+    if (E.IsFramework && (E.Group != frontend::Angled || E.IsUserSupplied))
+      llvm::llvm_report_error("Invalid option set!");
+    if (E.IsUserSupplied) {
+      if (E.Group == frontend::After) {
+        Res.push_back("-idirafter");
+      } else if (E.Group == frontend::Quoted) {
+        Res.push_back("-iquoted");
+      } else if (E.Group == frontend::System) {
+        Res.push_back("-isystem");
+      } else {
+        assert(E.Group == frontend::Angled && "Invalid group!");
+        Res.push_back(E.IsFramework ? "-F" : "-I");
+      }
+    } else {
+      if (E.Group != frontend::Angled && E.Group != frontend::System)
+        llvm::llvm_report_error("Invalid option set!");
+      Res.push_back(E.Group == frontend::Angled ? "-iwithprefixbefore" :
+                    "-iwithprefix");
+    }
+    Res.push_back(E.Path);
+  }
+
+  if (!Opts.EnvIncPath.empty()) {
+    // FIXME: Provide an option for this, and move env detection to driver.
+    llvm::llvm_report_error("Not yet implemented!");
+  }
+  if (!Opts.CEnvIncPath.empty()) {
+    // FIXME: Provide an option for this, and move env detection to driver.
+    llvm::llvm_report_error("Not yet implemented!");
+  }
+  if (!Opts.ObjCEnvIncPath.empty()) {
+    // FIXME: Provide an option for this, and move env detection to driver.
+    llvm::llvm_report_error("Not yet implemented!");
+  }
+  if (!Opts.CXXEnvIncPath.empty()) {
+    // FIXME: Provide an option for this, and move env detection to driver.
+    llvm::llvm_report_error("Not yet implemented!");
+  }
+  if (!Opts.ObjCXXEnvIncPath.empty()) {
+    // FIXME: Provide an option for this, and move env detection to driver.
+    llvm::llvm_report_error("Not yet implemented!");
+  }
+  if (!Opts.BuiltinIncludePath.empty()) {
+    // FIXME: Provide an option for this, and move to driver.
+  }
+  if (!Opts.UseStandardIncludes)
+    Res.push_back("-nostdinc");
+  if (Opts.Verbose)
+    Res.push_back("-v");
+}
+
+static void LangOptsToArgs(const LangOptions &Opts,
+                           std::vector<std::string> &Res) {
+  LangOptions DefaultLangOpts;
+
+  // FIXME: Need to set -std to get all the implicit options.
+
+  // FIXME: We want to only pass options relative to the defaults, which
+  // requires constructing a target. :(
+  //
+  // It would be better to push the all target specific choices into the driver,
+  // so that everything below that was more uniform.
+
+  if (Opts.Trigraphs)
+    Res.push_back("-trigraphs");
+  // Implicit based on the input kind:
+  //   AsmPreprocessor, CPlusPlus, ObjC1, ObjC2, OpenCL
+  // Implicit based on the input language standard:
+  //   BCPLComment, C99, CPlusPlus0x, Digraphs, GNUInline, ImplicitInt, GNUMode
+  if (Opts.DollarIdents)
+    Res.push_back("-fdollars-in-identifiers");
+  Res.push_back("-fms-extensions");
+  Res.push_back(Opts.Microsoft ? "1" : "0");
+  if (Opts.ObjCNonFragileABI)
+    Res.push_back("-fobjc-nonfragile-abi");
+  // NoInline is implicit.
+  if (!Opts.CXXOperatorNames)
+    Res.push_back("-fno-operator-names");
+  if (Opts.PascalStrings)
+    Res.push_back("-fpascal-strings");
+  if (Opts.WritableStrings)
+    Res.push_back("-fwritable-strings");
+  if (!Opts.LaxVectorConversions)
+    Res.push_back("-fno-lax-vector-conversions");
+  if (Opts.AltiVec)
+    Res.push_back("-faltivec");
+  Res.push_back("-fexceptions");
+  Res.push_back(Opts.Exceptions ? "1" : "0");
+  Res.push_back("-frtti");
+  Res.push_back(Opts.Rtti ? "1" : "0");
+  Res.push_back(Opts.NeXTRuntime ? "-fnext-runtime" : "-fgnu-runtime");
+  if (Opts.Freestanding)
+    Res.push_back("-ffreestanding");
+  if (Opts.NoBuiltin)
+    Res.push_back("-fno-builtin");
+  if (Opts.ThreadsafeStatics)
+    llvm::llvm_report_error("FIXME: Not yet implemented!");
+  if (Opts.POSIXThreads)
+    Res.push_back("-pthread");
+  Res.push_back("-fblocks");
+  Res.push_back(Opts.Blocks ? "1" : "0");
+  if (Opts.EmitAllDecls)
+    Res.push_back("-femit-all-decls");
+  Res.push_back("-fmath-errno");
+  Res.push_back(Opts.MathErrno ? "1" : "0");
+  if (Opts.OverflowChecking)
+    Res.push_back("-ftrapv");
+  if (Opts.HeinousExtensions)
+    Res.push_back("-fheinous-gnu-extensions");
+  // Optimize is implicit.
+  // OptimizeSize is implicit.
+  if (Opts.Static)
+    Res.push_back("-static-define");
+  if (Opts.PICLevel) {
+    Res.push_back("-pic-level");
+    Res.push_back(llvm::utostr(Opts.PICLevel));
+  }
+  if (Opts.ObjCGCBitmapPrint)
+    Res.push_back("-print-ivar-layout");
+  Res.push_back("-faccess-control");
+  Res.push_back(Opts.AccessControl ? "1" : "0");
+  Res.push_back("-fsigned-char");
+  Res.push_back(Opts.CharIsSigned ? "1" : "0");
+  Res.push_back("-fshort-wchar");
+  Res.push_back(Opts.ShortWChar ? "1" : "0");
+  if (!Opts.ElideConstructors)
+    Res.push_back("-fno-elide-constructors");
+  if (Opts.getGCMode() != LangOptions::NonGC) {
+    if (Opts.getGCMode() == LangOptions::HybridGC) {
+      Res.push_back("-fobjc-gc");
+    } else {
+      assert(Opts.getGCMode() == LangOptions::GCOnly && "Invalid GC mode!");
+      Res.push_back("-fobjc-gc-only");
+    }
+  }
+  if (Opts.getVisibilityMode() != LangOptions::Default) {
+    Res.push_back("-fvisibility");
+    if (Opts.getVisibilityMode() == LangOptions::Hidden) {
+      Res.push_back("default");
+    } else {
+      assert(Opts.getVisibilityMode() == LangOptions::Protected &&
+             "Invalid visibility!");
+      Res.push_back("protected");
+    }
+  }
+  if (Opts.getStackProtectorMode() != 0) {
+    Res.push_back("-stack-protector");
+    Res.push_back(llvm::utostr(Opts.getStackProtectorMode()));
+  }
+  if (Opts.getMainFileName()) {
+    Res.push_back("-main-file-name");
+    Res.push_back(Opts.getMainFileName());
+  }
+  if (Opts.InstantiationDepth != DefaultLangOpts.InstantiationDepth) {
+    Res.push_back("-ftemplate-depth");
+    Res.push_back(llvm::utostr(Opts.InstantiationDepth));
+  }
+  if (Opts.ObjCConstantStringClass) {
+    Res.push_back("-fconstant-string-class");
+    Res.push_back(Opts.ObjCConstantStringClass);
+  }
+}
+
+static void PreprocessorOptsToArgs(const PreprocessorOptions &Opts,
+                                   std::vector<std::string> &Res) {
+  for (unsigned i = 0, e = Opts.Macros.size(); i != e; ++i)
+    Res.push_back((Opts.Macros[i].second ? "-U" : "-D") + Opts.Macros[i].first);
+  for (unsigned i = 0, e = Opts.Includes.size(); i != e; ++i) {
+    Res.push_back("-include");
+    Res.push_back(Opts.Includes[i]);
+  }
+  for (unsigned i = 0, e = Opts.MacroIncludes.size(); i != e; ++i) {
+    Res.push_back("-imacros");
+    Res.push_back(Opts.Includes[i]);
+  }
+  if (!Opts.UsePredefines)
+    Res.push_back("-undef");
+  if (!Opts.ImplicitPCHInclude.empty()) {
+    Res.push_back("-implicit-pch-include");
+    Res.push_back(Opts.ImplicitPCHInclude);
+  }
+  if (!Opts.ImplicitPTHInclude.empty()) {
+    Res.push_back("-implicit-pth-include");
+    Res.push_back(Opts.ImplicitPTHInclude);
+  }
+  if (!Opts.TokenCache.empty()) {
+    Res.push_back("-token-cache");
+    Res.push_back(Opts.TokenCache);
+  }
+}
+
+static void PreprocessorOutputOptsToArgs(const PreprocessorOutputOptions &Opts,
+                                         std::vector<std::string> &Res) {
+  if (!Opts.ShowCPP && !Opts.ShowMacros)
+    llvm::llvm_report_error("Invalid option combination!");
+
+  if (Opts.ShowCPP && Opts.ShowMacros)
+    Res.push_back("-dD");
+  else if (!Opts.ShowCPP && Opts.ShowMacros)
+    Res.push_back("-dM");
+
+  if (!Opts.ShowLineMarkers)
+    Res.push_back("-P");
+  if (Opts.ShowComments)
+    Res.push_back("-C");
+  if (Opts.ShowMacroComments)
+    Res.push_back("-CC");
+}
+
+static void TargetOptsToArgs(const TargetOptions &Opts,
+                             std::vector<std::string> &Res) {
+  Res.push_back("-triple");
+  Res.push_back(Opts.Triple);
+  if (!Opts.CPU.empty()) {
+    Res.push_back("-target-cpu");
+    Res.push_back(Opts.CPU);
+  }
+  if (!Opts.ABI.empty()) {
+    Res.push_back("-target-abi");
+    Res.push_back(Opts.ABI);
+  }
+  for (unsigned i = 0, e = Opts.Features.size(); i != e; ++i) {
+    Res.push_back("-target-feature");
+    Res.push_back(Opts.Features[i]);
+  }
+}
+
+void CompilerInvocation::toArgs(std::vector<std::string> &Res) {
+  AnalyzerOptsToArgs(getAnalyzerOpts(), Res);
+  CodeGenOptsToArgs(getCodeGenOpts(), Res);
+  DependencyOutputOptsToArgs(getDependencyOutputOpts(), Res);
+  DiagnosticOptsToArgs(getDiagnosticOpts(), Res);
+  FrontendOptsToArgs(getFrontendOpts(), Res);
+  HeaderSearchOptsToArgs(getHeaderSearchOpts(), Res);
+  LangOptsToArgs(getLangOpts(), Res);
+  PreprocessorOptsToArgs(getPreprocessorOpts(), Res);
+  PreprocessorOutputOptsToArgs(getPreprocessorOutputOpts(), Res);
+  TargetOptsToArgs(getTargetOpts(), Res);
+}