diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 20c3074..f7480ea 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -10,8 +10,12 @@
 #include "Tools.h"
 
 #include "clang/Driver/Arg.h"
+#include "clang/Driver/ArgList.h"
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Job.h"
+#include "clang/Driver/HostInfo.h"
+#include "clang/Driver/Option.h"
+#include "clang/Driver/ToolChain.h"
 #include "clang/Driver/Util.h"
 
 #include "llvm/ADT/SmallVector.h"
@@ -27,49 +31,104 @@
                          const InputInfoList &Inputs,
                          const ArgList &TCArgs,
                          const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
+
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    if (II.isPipe())
+      CmdArgs.push_back("-");
+    else
+      CmdArgs.push_back(II.getInputFilename());
+  }
+
+  if (Output.isPipe()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back("-");
+  } else if (const char *N = Output.getInputFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(N);
+  }
+
+  Dest.addCommand(new Command("clang", CmdArgs));
 }
 
-void gcc::Preprocess::ConstructJob(Compilation &C, const JobAction &JA,
-                                   Job &Dest,
-                                   const InputInfo &Output,
-                                   const InputInfoList &Inputs,
-                                   const ArgList &TCArgs,
-                                   const char *LinkingOutput) const {
+void gcc::Common::ConstructJob(Compilation &C, const JobAction &JA,
+                               Job &Dest,
+                               const InputInfo &Output,
+                               const InputInfoList &Inputs,
+                               const ArgList &TCArgs,
+                               const char *LinkingOutput) const {
+  ArgStringList CmdArgs;
 
+  for (ArgList::const_iterator 
+         it = TCArgs.begin(), ie = TCArgs.end(); it != ie; ++it) {
+    Arg *A = *it;
+    if (A->getOption().hasForwardToGCC())
+      A->render(TCArgs, CmdArgs);
+  }
+  
+  RenderExtraToolArgs(CmdArgs);
+
+  // If using a driver driver, force the arch.
+  if (getToolChain().getHost().useDriverDriver()) {
+    CmdArgs.push_back("-arch");
+    CmdArgs.push_back(getToolChain().getArchName().c_str());
+  }
+
+  if (Output.isPipe()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back("-");
+  } else if (const char *N = Output.getInputFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(N);
+  } else
+    CmdArgs.push_back("-fsyntax-only");
+
+
+  // Only pass -x if gcc will understand it; otherwise hope gcc
+  // understands the suffix correctly. The main use case this would go
+  // wrong in is for linker inputs if they happened to have an odd
+  // suffix; really the only way to get this to happen is a command
+  // like '-x foobar a.c' which will treat a.c like a linker input.
+  //
+  // FIXME: For the linker case specifically, can we safely convert
+  // inputs into '-Wl,' options?
+  for (InputInfoList::const_iterator
+         it = Inputs.begin(), ie = Inputs.end(); it != ie; ++it) {
+    const InputInfo &II = *it;
+    if (types::canTypeBeUserSpecified(II.getType())) {
+      CmdArgs.push_back("-x");
+      CmdArgs.push_back(types::getTypeName(II.getType()));
+    }
+
+    if (II.isPipe())
+      CmdArgs.push_back("-");
+    else
+      // FIXME: Linker inputs
+      CmdArgs.push_back(II.getInputFilename());
+  }
+
+  Dest.addCommand(new Command("gcc", CmdArgs));
 }
 
-void gcc::Precompile::ConstructJob(Compilation &C, const JobAction &JA,
-                                   Job &Dest,
-                                   const InputInfo &Output,
-                                   const InputInfoList &Inputs,
-                                   const ArgList &TCArgs,
-                                   const char *LinkingOutput) const {
-
+void gcc::Preprocess::RenderExtraToolArgs(ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-E");
 }
 
-void gcc::Compile::ConstructJob(Compilation &C, const JobAction &JA,
-                                Job &Dest,
-                                const InputInfo &Output,
-                                const InputInfoList &Inputs,
-                                const ArgList &TCArgs,
-                                const char *LinkingOutput) const {
-
+void gcc::Precompile::RenderExtraToolArgs(ArgStringList &CmdArgs) const {
+  // The type is good enough.
 }
 
-void gcc::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
-                                 Job &Dest,
-                                 const InputInfo &Output,
-                                 const InputInfoList &Inputs,
-                                 const ArgList &TCArgs,
-                                 const char *LinkingOutput) const {
-
+void gcc::Compile::RenderExtraToolArgs(ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-S");
 }
 
-void gcc::Link::ConstructJob(Compilation &C, const JobAction &JA,
-                             Job &Dest,
-                             const InputInfo &Output,
-                             const InputInfoList &Inputs,
-                             const ArgList &TCArgs,
-                             const char *LinkingOutput) const {
-
+void gcc::Assemble::RenderExtraToolArgs(ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-c");
 }
+
+void gcc::Link::RenderExtraToolArgs(ArgStringList &CmdArgs) const {
+  // The types are (hopefully) good enough.
+}
+