Move ownership of Action objects into Compilation.

[jlebar]

Summary

Previously, Actions owned their inputs. Now the Compilation object owns all Actions. This makes constructing Action graphs which are DAGs much simpler. It also just simplifies in general the ownership semantics of Actions.

[jlebar]

The main reason I want this is for CUDA. The way CUDA compilation will work, once I finish my patch, is: For each GPU arch, we compile device code to assembly (ptx) and then assemble the ptx into an object file (cubin). We then pass the cubins *and* ptx files to nVidia's fatbinary program, which "links" them into one blob. We then embed the blob in the host code.

So in this scheme, our Action graph is a DAG: The ptx is used as an input both to the cubin and fatbin actions. Making this DAG work in the absence of this patch is...pretty unpleasant.

[tra]

lib/Driver/Action.cpp

61–62

I guess we no longer need this destructor.

lib/Driver/Driver.cpp

1051–1052

unneeded {}

[jlebar]

Address review comments.

[jlebar]

Switch to maintaining ownership of the Actions within the Compilation.

[jlebar]

Clear both Actions and OwningActions in Compilation::initCompilationForDiagnostics().

[jlebar]

Changed to move ownership into Compilation, as discussed earlier today. Please have a look.

[tra]

include/clang/Driver/Action.h

36

There's no API to pass ownership to Compilation explicitly, so the only way for an Action to be owned by Compilation is to create it with MakeAction.

Perhaps "Actions created with MakeAction<>() are owned by Compilation"

BTW, should we (can we?) make MakeAction<>() the only way to create actions?

[cfe-commits]

• msg-516-145.txt159 BDownload

[dblaikie]

include/clang/Driver/Compilation.h

53

Seems like this name isn't quite right ("OwningActions" sounds like "these are the actions that own <something>") - perhaps "AllActions"? (maybe "ActionHolder"? Not sure)

117

Did you find this static_assert to be particularly helpful? Similar errors (though somewhat more verbose) would be produced during the push_back call a few lines down anyway.

119

Up to you, but we usually just drop the "std::unique_ptr<T>" in favor of "auto" when the RHS has "make_unique".

[jlebar]

Address tra and dblaikie's review comments.

include/clang/Driver/Action.h

36

Updated the comment.

include/clang/Driver/Compilation.h

117

Fair enough. I got rid of it but changed my unique_ptr into a unique_ptr<Action> so that we'll get an error somewhere other than inside the bowels of SmallVector.

119

Done, but then I realized I can just use operator new and skirt this entirely.

[echristo]

LGTM. Thanks for doing this :)

-eric

include/clang/Driver/Action.h

 ///
 /// An action represents an edge in the compilation graph; typically
 /// it is a job to transform an input using some tool.
 ///
 /// The current driver is hard wired to expect actions which produce a
 /// single primary output, at least in terms of controlling the
 /// compilation. Actions can produce auxiliary files, but can only
 /// produce a single output to feed into subsequent actions.
+///
+/// Actions are usually owned by a Compilation, which creates new
+/// actions via MakeAction().
 class Action {
 public:
   typedef ActionList::size_type size_type;
   typedef ActionList::iterator iterator;
   typedef ActionList::const_iterator const_iterator;
 
   enum ActionClass {
     InputClass = 0,

 private:
   ActionClass Kind;
 
   /// The output type of this action.
   types::ID Type;
 
   ActionList Inputs;
 
-  unsigned OwnsInputs : 1;
-
 protected:
-  Action(ActionClass Kind, types::ID Type)
-    : Kind(Kind), Type(Type), OwnsInputs(true)  {}
-  Action(ActionClass Kind, std::unique_ptr<Action> Input, types::ID Type)
-      : Kind(Kind), Type(Type), Inputs(1, Input.release()), OwnsInputs(true) {
-  }
-  Action(ActionClass Kind, std::unique_ptr<Action> Input)
-      : Kind(Kind), Type(Input->getType()), Inputs(1, Input.release()),
-        OwnsInputs(true) {}
+  Action(ActionClass Kind, types::ID Type) : Action(Kind, ActionList(), Type) {}
+  Action(ActionClass Kind, Action *Input, types::ID Type)
+      : Action(Kind, ActionList({Input}), Type) {}
+  Action(ActionClass Kind, Action *Input)
+      : Action(Kind, ActionList({Input}), Input->getType()) {}
   Action(ActionClass Kind, const ActionList &Inputs, types::ID Type)
-    : Kind(Kind), Type(Type), Inputs(Inputs), OwnsInputs(true) {}
+      : Kind(Kind), Type(Type), Inputs(Inputs) {}
+
 public:
   virtual ~Action();
 
   const char *getClassName() const { return Action::getClassName(getKind()); }
 
-  bool getOwnsInputs() { return OwnsInputs; }
-  void setOwnsInputs(bool Value) { OwnsInputs = Value; }
-
   ActionClass getKind() const { return Kind; }
   types::ID getType() const { return Type; }
 
   ActionList &getInputs() { return Inputs; }
   const ActionList &getInputs() const { return Inputs; }
 
   size_type size() const { return Inputs.size(); }
 

 
 class BindArchAction : public Action {
   virtual void anchor();
   /// The architecture to bind, or 0 if the default architecture
   /// should be bound.
   const char *ArchName;
 
 public:
-  BindArchAction(std::unique_ptr<Action> Input, const char *ArchName);
+  BindArchAction(Action *Input, const char *ArchName);
 
   const char *getArchName() const { return ArchName; }
 
   static bool classof(const Action *A) {
     return A->getKind() == BindArchClass;
   }
 };
 
 class CudaDeviceAction : public Action {
   virtual void anchor();
   /// GPU architecture to bind -- e.g 'sm_35'.
   const char *GpuArchName;
   /// True when action results are not consumed by the host action (e.g when
   /// -fsyntax-only or --cuda-device-only options are used).
   bool AtTopLevel;
 
 public:
-  CudaDeviceAction(std::unique_ptr<Action> Input, const char *ArchName,
-                   bool AtTopLevel);
+  CudaDeviceAction(Action *Input, const char *ArchName, bool AtTopLevel);
 
   const char *getGpuArchName() const { return GpuArchName; }
   bool isAtTopLevel() const { return AtTopLevel; }
 
   static bool classof(const Action *A) {
     return A->getKind() == CudaDeviceClass;
   }
 };
 
 class CudaHostAction : public Action {
   virtual void anchor();
   ActionList DeviceActions;
 
 public:
-  CudaHostAction(std::unique_ptr<Action> Input,
-                 const ActionList &DeviceActions);
-  ~CudaHostAction() override;
+  CudaHostAction(Action *Input, const ActionList &DeviceActions);
 
   const ActionList &getDeviceActions() const { return DeviceActions; }
 
   static bool classof(const Action *A) { return A->getKind() == CudaHostClass; }
 };
 
 class JobAction : public Action {
   virtual void anchor();
 protected:
-  JobAction(ActionClass Kind, std::unique_ptr<Action> Input, types::ID Type);
+  JobAction(ActionClass Kind, Action *Input, types::ID Type);
   JobAction(ActionClass Kind, const ActionList &Inputs, types::ID Type);
 
 public:
   static bool classof(const Action *A) {
     return (A->getKind() >= JobClassFirst &&
             A->getKind() <= JobClassLast);
   }
 };
 
 class PreprocessJobAction : public JobAction {
   void anchor() override;
 public:
-  PreprocessJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  PreprocessJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == PreprocessJobClass;
   }
 };
 
 class PrecompileJobAction : public JobAction {
   void anchor() override;
 public:
-  PrecompileJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  PrecompileJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == PrecompileJobClass;
   }
 };
 
 class AnalyzeJobAction : public JobAction {
   void anchor() override;
 public:
-  AnalyzeJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  AnalyzeJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == AnalyzeJobClass;
   }
 };
 
 class MigrateJobAction : public JobAction {
   void anchor() override;
 public:
-  MigrateJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  MigrateJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == MigrateJobClass;
   }
 };
 
 class CompileJobAction : public JobAction {
   void anchor() override;
 public:
-  CompileJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  CompileJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == CompileJobClass;
   }
 };
 
 class BackendJobAction : public JobAction {
   void anchor() override;
 public:
-  BackendJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  BackendJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == BackendJobClass;
   }
 };
 
 class AssembleJobAction : public JobAction {
   void anchor() override;
 public:
-  AssembleJobAction(std::unique_ptr<Action> Input, types::ID OutputType);
+  AssembleJobAction(Action *Input, types::ID OutputType);
 
   static bool classof(const Action *A) {
     return A->getKind() == AssembleJobClass;
   }
 };
 
 class LinkJobAction : public JobAction {
   void anchor() override;
public:
   static bool classof(const Action *A) {
     return A->getKind() == DsymutilJobClass;
   }
 };
 
 class VerifyJobAction : public JobAction {
   void anchor() override;
 public:
-  VerifyJobAction(ActionClass Kind, std::unique_ptr<Action> Input,
-                  types::ID Type);
+  VerifyJobAction(ActionClass Kind, Action *Input, types::ID Type);
   static bool classof(const Action *A) {
     return A->getKind() == VerifyDebugInfoJobClass ||
            A->getKind() == VerifyPCHJobClass;
   }
 };
 
 class VerifyDebugInfoJobAction : public VerifyJobAction {
   void anchor() override;
 public:
-  VerifyDebugInfoJobAction(std::unique_ptr<Action> Input, types::ID Type);
+  VerifyDebugInfoJobAction(Action *Input, types::ID Type);
   static bool classof(const Action *A) {
     return A->getKind() == VerifyDebugInfoJobClass;
   }
 };
 
 class VerifyPCHJobAction : public VerifyJobAction {
   void anchor() override;
 public:
-  VerifyPCHJobAction(std::unique_ptr<Action> Input, types::ID Type);
+  VerifyPCHJobAction(Action *Input, types::ID Type);
   static bool classof(const Action *A) {
     return A->getKind() == VerifyPCHJobClass;
   }
 };
 
 } // end namespace driver
 } // end namespace clang
 
 #endif

include/clang/Driver/Compilation.h

class Compilation {
 
   /// The original (untranslated) input argument list.
   llvm::opt::InputArgList *Args;
 
   /// The driver translated arguments. Note that toolchains may perform their
   /// own argument translation.
   llvm::opt::DerivedArgList *TranslatedArgs;
 
-  /// The list of actions.
+  /// The list of actions we've created via MakeAction.  This is not accessible
+  /// to consumers; it's here just to manage ownership.
+  std::vector<std::unique_ptr<Action>> AllActions;
+
+  /// The list of actions.  This is maintained and modified by consumers, via
+  /// getActions().
   ActionList Actions;
 
   /// The root list of jobs.
   JobList Jobs;
 
   /// Cache of translated arguments for a particular tool chain and bound
   /// architecture.
   llvm::DenseMap<std::pair<const ToolChain *, const char *>,
public:
 
   const llvm::opt::DerivedArgList &getArgs() const { return *TranslatedArgs; }
 
   llvm::opt::DerivedArgList &getArgs() { return *TranslatedArgs; }
 
   ActionList &getActions() { return Actions; }
   const ActionList &getActions() const { return Actions; }
 
+  /// Creates a new Action owned by this Compilation.
+  ///
+  /// The new Action is *not* added to the list returned by getActions().
+  template <typename T, typename... Args> T *MakeAction(Args &&... Arg) {
+    T *RawPtr = new T(std::forward<Args>(Arg)...);
+    AllActions.push_back(std::unique_ptr<Action>(RawPtr));
+    return RawPtr;
+  }
+
   JobList &getJobs() { return Jobs; }
   const JobList &getJobs() const { return Jobs; }
 
   void addCommand(std::unique_ptr<Command> C) { Jobs.addJob(std::move(C)); }
 
   const llvm::opt::ArgStringList &getTempFiles() const { return TempFiles; }
 
   const ArgStringMap &getResultFiles() const { return ResultFiles; }

include/clang/Driver/Driver.h

public:
   ///
   /// \return Whether any compilation should be built for this
   /// invocation.
   bool HandleImmediateArgs(const Compilation &C);
 
   /// ConstructAction - Construct the appropriate action to do for
   /// \p Phase on the \p Input, taking in to account arguments
   /// like -fsyntax-only or --analyze.
-  std::unique_ptr<Action>
-  ConstructPhaseAction(const ToolChain &TC, const llvm::opt::ArgList &Args,
-                       phases::ID Phase, std::unique_ptr<Action> Input) const;
+  Action *ConstructPhaseAction(Compilation &C, const ToolChain &TC,
+                               const llvm::opt::ArgList &Args, phases::ID Phase,
+                               Action *Input) const;
 
   /// BuildJobsForAction - Construct the jobs to perform for the
   /// action \p A.
   void BuildJobsForAction(Compilation &C,
                           const Action *A,
                           const ToolChain *TC,
                           const char *BoundArch,
                           bool AtTopLevel,

lib/Driver/Action.cpp

 //===--- Action.cpp - Abstract compilation steps --------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/Driver/Action.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <cassert>
 using namespace clang::driver;
 using namespace llvm::opt;
 
-Action::~Action() {
-  if (OwnsInputs) {
-    for (iterator it = begin(), ie = end(); it != ie; ++it)
-      delete *it;
-  }
-}
+Action::~Action() {}
 
 const char *Action::getClassName(ActionClass AC) {
   switch (AC) {
   case InputClass: return "input";
   case BindArchClass: return "bind-arch";
   case CudaDeviceClass: return "cuda-device";
   case CudaHostClass: return "cuda-host";
   case PreprocessJobClass: return "preprocessor";

 void InputAction::anchor() {}
 
 InputAction::InputAction(const Arg &_Input, types::ID _Type)
   : Action(InputClass, _Type), Input(_Input) {
 }
 
 void BindArchAction::anchor() {}
 
-BindArchAction::BindArchAction(std::unique_ptr<Action> Input,
-                               const char *_ArchName)
-    : Action(BindArchClass, std::move(Input)), ArchName(_ArchName) {}
+BindArchAction::BindArchAction(Action *Input, const char *_ArchName)
+    : Action(BindArchClass, Input), ArchName(_ArchName) {}
 
 void CudaDeviceAction::anchor() {}
 
-CudaDeviceAction::CudaDeviceAction(std::unique_ptr<Action> Input,
-                                   const char *ArchName, bool AtTopLevel)
-    : Action(CudaDeviceClass, std::move(Input)), GpuArchName(ArchName),
+CudaDeviceAction::CudaDeviceAction(Action *Input, const char *ArchName,
+                                   bool AtTopLevel)
+    : Action(CudaDeviceClass, Input), GpuArchName(ArchName),
       AtTopLevel(AtTopLevel) {}
 
 void CudaHostAction::anchor() {}
 
-CudaHostAction::CudaHostAction(std::unique_ptr<Action> Input,
-                               const ActionList &DeviceActions)
-    : Action(CudaHostClass, std::move(Input)), DeviceActions(DeviceActions) {}
-
-CudaHostAction::~CudaHostAction() {
-  for (auto &DA : DeviceActions)
-    delete DA;
-}
+CudaHostAction::CudaHostAction(Action *Input, const ActionList &DeviceActions)
+    : Action(CudaHostClass, Input), DeviceActions(DeviceActions) {}
 
 void JobAction::anchor() {}
 
-JobAction::JobAction(ActionClass Kind, std::unique_ptr<Action> Input,
-                     types::ID Type)
-    : Action(Kind, std::move(Input), Type) {}
+JobAction::JobAction(ActionClass Kind, Action *Input, types::ID Type)
+    : Action(Kind, Input, Type) {}
 
 JobAction::JobAction(ActionClass Kind, const ActionList &Inputs, types::ID Type)
   : Action(Kind, Inputs, Type) {
 }
 
 void PreprocessJobAction::anchor() {}
 
-PreprocessJobAction::PreprocessJobAction(std::unique_ptr<Action> Input,
-                                         types::ID OutputType)
-    : JobAction(PreprocessJobClass, std::move(Input), OutputType) {}
+PreprocessJobAction::PreprocessJobAction(Action *Input, types::ID OutputType)
+    : JobAction(PreprocessJobClass, Input, OutputType) {}
 
 void PrecompileJobAction::anchor() {}
 
-PrecompileJobAction::PrecompileJobAction(std::unique_ptr<Action> Input,
-                                         types::ID OutputType)
-    : JobAction(PrecompileJobClass, std::move(Input), OutputType) {}
+PrecompileJobAction::PrecompileJobAction(Action *Input, types::ID OutputType)
+    : JobAction(PrecompileJobClass, Input, OutputType) {}
 
 void AnalyzeJobAction::anchor() {}
 
-AnalyzeJobAction::AnalyzeJobAction(std::unique_ptr<Action> Input,
-                                   types::ID OutputType)
-    : JobAction(AnalyzeJobClass, std::move(Input), OutputType) {}
+AnalyzeJobAction::AnalyzeJobAction(Action *Input, types::ID OutputType)
+    : JobAction(AnalyzeJobClass, Input, OutputType) {}
 
 void MigrateJobAction::anchor() {}
 
-MigrateJobAction::MigrateJobAction(std::unique_ptr<Action> Input,
-                                   types::ID OutputType)
-    : JobAction(MigrateJobClass, std::move(Input), OutputType) {}
+MigrateJobAction::MigrateJobAction(Action *Input, types::ID OutputType)
+    : JobAction(MigrateJobClass, Input, OutputType) {}
 
 void CompileJobAction::anchor() {}
 
-CompileJobAction::CompileJobAction(std::unique_ptr<Action> Input,
-                                   types::ID OutputType)
-    : JobAction(CompileJobClass, std::move(Input), OutputType) {}
+CompileJobAction::CompileJobAction(Action *Input, types::ID OutputType)
+    : JobAction(CompileJobClass, Input, OutputType) {}
 
 void BackendJobAction::anchor() {}
 
-BackendJobAction::BackendJobAction(std::unique_ptr<Action> Input,
-                                   types::ID OutputType)
-    : JobAction(BackendJobClass, std::move(Input), OutputType) {}
+BackendJobAction::BackendJobAction(Action *Input, types::ID OutputType)
+    : JobAction(BackendJobClass, Input, OutputType) {}
 
 void AssembleJobAction::anchor() {}
 
-AssembleJobAction::AssembleJobAction(std::unique_ptr<Action> Input,
-                                     types::ID OutputType)
-    : JobAction(AssembleJobClass, std::move(Input), OutputType) {}
+AssembleJobAction::AssembleJobAction(Action *Input, types::ID OutputType)
+    : JobAction(AssembleJobClass, Input, OutputType) {}
 
 void LinkJobAction::anchor() {}
 
 LinkJobAction::LinkJobAction(ActionList &Inputs, types::ID Type)
   : JobAction(LinkJobClass, Inputs, Type) {
 }
 
 void LipoJobAction::anchor() {}
 
 LipoJobAction::LipoJobAction(ActionList &Inputs, types::ID Type)
   : JobAction(LipoJobClass, Inputs, Type) {
 }
 
 void DsymutilJobAction::anchor() {}
 
 DsymutilJobAction::DsymutilJobAction(ActionList &Inputs, types::ID Type)
   : JobAction(DsymutilJobClass, Inputs, Type) {
 }
 
 void VerifyJobAction::anchor() {}
 
-VerifyJobAction::VerifyJobAction(ActionClass Kind,
-                                 std::unique_ptr<Action> Input, types::ID Type)
-    : JobAction(Kind, std::move(Input), Type) {
+VerifyJobAction::VerifyJobAction(ActionClass Kind, Action *Input,
+                                 types::ID Type)
+    : JobAction(Kind, Input, Type) {
   assert((Kind == VerifyDebugInfoJobClass || Kind == VerifyPCHJobClass) &&
          "ActionClass is not a valid VerifyJobAction");
 }
 
 void VerifyDebugInfoJobAction::anchor() {}
 
-VerifyDebugInfoJobAction::VerifyDebugInfoJobAction(
-    std::unique_ptr<Action> Input, types::ID Type)
-    : VerifyJobAction(VerifyDebugInfoJobClass, std::move(Input), Type) {}
+VerifyDebugInfoJobAction::VerifyDebugInfoJobAction(Action *Input,
+                                                   types::ID Type)
+    : VerifyJobAction(VerifyDebugInfoJobClass, Input, Type) {}
 
 void VerifyPCHJobAction::anchor() {}
 
-VerifyPCHJobAction::VerifyPCHJobAction(std::unique_ptr<Action> Input,
-                                       types::ID Type)
-    : VerifyJobAction(VerifyPCHJobClass, std::move(Input), Type) {}
+VerifyPCHJobAction::VerifyPCHJobAction(Action *Input, types::ID Type)
+    : VerifyJobAction(VerifyPCHJobClass, Input, Type) {}

lib/Driver/Compilation.cpp

Compilation::~Compilation() {
 
   // Free any derived arg lists.
   for (llvm::DenseMap<std::pair<const ToolChain*, const char*>,
                       DerivedArgList*>::iterator it = TCArgs.begin(),
          ie = TCArgs.end(); it != ie; ++it)
     if (it->second != TranslatedArgs)
       delete it->second;
 
-  // Free the actions, if built.
-  for (ActionList::iterator it = Actions.begin(), ie = Actions.end();
-       it != ie; ++it)
-    delete *it;
-
   // Free redirections of stdout/stderr.
   if (Redirects) {
     delete Redirects[1];
     delete Redirects[2];
     delete [] Redirects;
   }
 }
 
if (int Res = ExecuteCommand(Job, FailingCommand))
       FailingCommands.push_back(std::make_pair(Res, FailingCommand));
   }
 }
 
 void Compilation::initCompilationForDiagnostics() {
   ForDiagnostics = true;
 
   // Free actions and jobs.
-  DeleteContainerPointers(Actions);
+  Actions.clear();
+  AllActions.clear();
   Jobs.clear();
 
   // Clear temporary/results file lists.
   TempFiles.clear();
   ResultFiles.clear();
   FailureResultFiles.clear();
 
   // Remove any user specified output.  Claim any unclaimed arguments, so as

lib/Driver/Driver.cpp

for (Action* Act : SingleActions) {
     // right name without overwriting it. We could remove this oddity by just
     // changing the output names to include the arch, which would also fix
     // -save-temps. Compatibility wins for now.
 
     if (Archs.size() > 1 && !types::canLipoType(Act->getType()))
       Diag(clang::diag::err_drv_invalid_output_with_multiple_archs)
           << types::getTypeName(Act->getType());
 
     ActionList Inputs;
-    for (unsigned i = 0, e = Archs.size(); i != e; ++i) {
-      Inputs.push_back(
-          new BindArchAction(std::unique_ptr<Action>(Act), Archs[i]));
-      if (i != 0)
-        Inputs.back()->setOwnsInputs(false);
-    }
+    for (unsigned i = 0, e = Archs.size(); i != e; ++i)
+      Inputs.push_back(C.MakeAction<BindArchAction>(Act, Archs[i]));
 
     // Lipo if necessary, we do it this way because we need to set the arch flag
     // so that -Xarch_ gets overwritten.
     if (Inputs.size() == 1 || Act->getType() == types::TY_Nothing)
       Actions.append(Inputs.begin(), Inputs.end());
     else
-      Actions.push_back(new LipoJobAction(Inputs, Act->getType()));
+      Actions.push_back(C.MakeAction<LipoJobAction>(Inputs, Act->getType()));
 
     // Handle debug info queries.
     Arg *A = Args.getLastArg(options::OPT_g_Group);
     if (A && !A->getOption().matches(options::OPT_g0) &&
         !A->getOption().matches(options::OPT_gstabs) &&
         ContainsCompileOrAssembleAction(Actions.back())) {
 
       // Add a 'dsymutil' step if necessary, when debug info is enabled and we
       // have a compile input. We need to run 'dsymutil' ourselves in such cases
       // because the debug info will refer to a temporary object file which
       // will be removed at the end of the compilation process.
       if (Act->getType() == types::TY_Image) {
         ActionList Inputs;
         Inputs.push_back(Actions.back());
         Actions.pop_back();
-        Actions.push_back(new DsymutilJobAction(Inputs, types::TY_dSYM));
+        Actions.push_back(
+            C.MakeAction<DsymutilJobAction>(Inputs, types::TY_dSYM));
       }
 
       // Verify the debug info output.
       if (Args.hasArg(options::OPT_verify_debug_info)) {
-        std::unique_ptr<Action> VerifyInput(Actions.back());
+        Action* LastAction = Actions.back();
         Actions.pop_back();
-        Actions.push_back(new VerifyDebugInfoJobAction(std::move(VerifyInput),
-                                                       types::TY_Nothing));
+        Actions.push_back(C.MakeAction<VerifyDebugInfoJobAction>(
+            LastAction, types::TY_Nothing));
       }
     }
   }
 }
 
 /// \brief Check that the file referenced by Value exists. If it doesn't,
 /// issue a diagnostic and return false.
 static bool DiagnoseInputExistence(const Driver &D, const DerivedArgList &Args,

 
 // For each unique --cuda-gpu-arch= argument creates a TY_CUDA_DEVICE
 // input action and then wraps each in CudaDeviceAction paired with
 // appropriate GPU arch name. In case of partial (i.e preprocessing
 // only) or device-only compilation, each device action is added to /p
 // Actions and /p Current is released. Otherwise the function creates
 // and returns a new CudaHostAction which wraps /p Current and device
 // side actions.
-static std::unique_ptr<Action>
-buildCudaActions(Compilation &C, DerivedArgList &Args, const Arg *InputArg,
-                 std::unique_ptr<Action> HostAction, ActionList &Actions) {
+static Action *buildCudaActions(Compilation &C, DerivedArgList &Args,
+                                const Arg *InputArg, Action *HostAction,
+                                ActionList &Actions) {
   Arg *PartialCompilationArg = Args.getLastArg(options::OPT_cuda_host_only,
                                                options::OPT_cuda_device_only);
   // Host-only compilation case.
   if (PartialCompilationArg &&
       PartialCompilationArg->getOption().matches(options::OPT_cuda_host_only))
-    return std::unique_ptr<Action>(
-        new CudaHostAction(std::move(HostAction), {}));
+    return C.MakeAction<CudaHostAction>(HostAction, ActionList());
 
   // Collect all cuda_gpu_arch parameters, removing duplicates.
   SmallVector<const char *, 4> GpuArchList;
   llvm::StringSet<> GpuArchNames;
   for (Arg *A : Args) {
     if (!A->getOption().matches(options::OPT_cuda_gpu_arch_EQ))
       continue;
     A->claim();
if (PartialCompilation || DeviceOnlyCompilation) {
     if (Args.hasArg(options::OPT_o) &&
         (!DeviceOnlyCompilation || GpuArchList.size() > 1)) {
       C.getDriver().Diag(
           clang::diag::err_drv_output_argument_with_multiple_files);
       return nullptr;
     }
 
     for (unsigned I = 0, E = GpuArchList.size(); I != E; ++I)
-      Actions.push_back(new CudaDeviceAction(
-          std::unique_ptr<Action>(CudaDeviceActions[I]), GpuArchList[I],
+      Actions.push_back(C.MakeAction<CudaDeviceAction>(CudaDeviceActions[I],
+                                                       GpuArchList[I],
                                                        /* AtTopLevel */ true));
     // Kill host action in case of device-only compilation.
     if (DeviceOnlyCompilation)
-      HostAction.reset(nullptr);
+      return nullptr;
     return HostAction;
   }
 
   // Outputs of device actions during complete CUDA compilation get created
   // with AtTopLevel=false and become inputs for the host action.
   ActionList DeviceActions;
   for (unsigned I = 0, E = GpuArchList.size(); I != E; ++I)
-    DeviceActions.push_back(new CudaDeviceAction(
-        std::unique_ptr<Action>(CudaDeviceActions[I]), GpuArchList[I],
+    DeviceActions.push_back(
+        C.MakeAction<CudaDeviceAction>(CudaDeviceActions[I], GpuArchList[I],
                                        /* AtTopLevel */ false));
   // Return a new host action that incorporates original host action and all
   // device actions.
-  return std::unique_ptr<Action>(
-      new CudaHostAction(std::move(HostAction), DeviceActions));
+  return C.MakeAction<CudaHostAction>(HostAction, DeviceActions);
 }
 
 void Driver::BuildActions(Compilation &C, const ToolChain &TC,
                           DerivedArgList &Args, const InputList &Inputs,
                           ActionList &Actions) const {
   llvm::PrettyStackTraceString CrashInfo("Building compilation actions");
 
   if (!SuppressMissingInputWarning && Inputs.empty()) {
for (auto &I : Inputs) {
 
     phases::ID CudaInjectionPhase =
         (phases::Compile < FinalPhase &&
          llvm::find(PL, phases::Compile) != PL.end())
             ? phases::Compile
             : FinalPhase;
 
     // Build the pipeline for this file.
-    std::unique_ptr<Action> Current(new InputAction(*InputArg, InputType));
+    Action *Current = C.MakeAction<InputAction>(*InputArg, InputType);
     for (SmallVectorImpl<phases::ID>::iterator i = PL.begin(), e = PL.end();
          i != e; ++i) {
       phases::ID Phase = *i;
 
       // We are done if this step is past what the user requested.
       if (Phase > FinalPhase)
         break;
 
       // Queue linker inputs.
       if (Phase == phases::Link) {
         assert((i + 1) == e && "linking must be final compilation step.");
-        LinkerInputs.push_back(Current.release());
+        LinkerInputs.push_back(Current);
+        Current = nullptr;
         break;
       }
 
       // Some types skip the assembler phase (e.g., llvm-bc), but we can't
       // encode this in the steps because the intermediate type depends on
       // arguments. Just special case here.
       if (Phase == phases::Assemble && Current->getType() != types::TY_PP_Asm)
         continue;
 
       // Otherwise construct the appropriate action.
-      Current = ConstructPhaseAction(TC, Args, Phase, std::move(Current));
+      Current = ConstructPhaseAction(C, TC, Args, Phase, Current);
 
       if (InputType == types::TY_CUDA && Phase == CudaInjectionPhase) {
-        Current =
-            buildCudaActions(C, Args, InputArg, std::move(Current), Actions);
+        Current = buildCudaActions(C, Args, InputArg, Current, Actions);
         if (!Current)
           break;
       }
 
       if (Current->getType() == types::TY_Nothing)
         break;
     }
 
     // If we ended with something, add to the output list.
     if (Current)
-      Actions.push_back(Current.release());
+      Actions.push_back(Current);
   }
 
   // Add a link action if necessary.
   if (!LinkerInputs.empty())
-    Actions.push_back(new LinkJobAction(LinkerInputs, types::TY_Image));
+    Actions.push_back(
+        C.MakeAction<LinkJobAction>(LinkerInputs, types::TY_Image));
 
   // If we are linking, claim any options which are obviously only used for
   // compilation.
   if (FinalPhase == phases::Link && PL.size() == 1) {
     Args.ClaimAllArgs(options::OPT_CompileOnly_Group);
     Args.ClaimAllArgs(options::OPT_cl_compile_Group);
   }
 
   // Claim ignored clang-cl options.
   Args.ClaimAllArgs(options::OPT_cl_ignored_Group);
 
   // Claim --cuda-host-only arg which may be passed to non-CUDA
   // compilations and should not trigger warnings there.
   Args.ClaimAllArgs(options::OPT_cuda_host_only);
 }
 
-std::unique_ptr<Action>
-Driver::ConstructPhaseAction(const ToolChain &TC, const ArgList &Args,
-                             phases::ID Phase,
-                             std::unique_ptr<Action> Input) const {
+Action *Driver::ConstructPhaseAction(Compilation &C, const ToolChain &TC,
+                                     const ArgList &Args, phases::ID Phase,
+                                     Action *Input) const {
   llvm::PrettyStackTraceString CrashInfo("Constructing phase actions");
   // Build the appropriate action.
   switch (Phase) {
   case phases::Link:
     llvm_unreachable("link action invalid here.");
   case phases::Preprocess: {
     types::ID OutputTy;
     // -{M, MM} alter the output type.
     if (Args.hasArg(options::OPT_M, options::OPT_MM)) {
       OutputTy = types::TY_Dependencies;
     } else {
       OutputTy = Input->getType();
       if (!Args.hasFlag(options::OPT_frewrite_includes,
                         options::OPT_fno_rewrite_includes, false) &&
           !CCGenDiagnostics)
         OutputTy = types::getPreprocessedType(OutputTy);
       assert(OutputTy != types::TY_INVALID &&
              "Cannot preprocess this input type!");
     }
-    return llvm::make_unique<PreprocessJobAction>(std::move(Input), OutputTy);
+    return C.MakeAction<PreprocessJobAction>(Input, OutputTy);
   }
   case phases::Precompile: {
     types::ID OutputTy = types::TY_PCH;
     if (Args.hasArg(options::OPT_fsyntax_only)) {
       // Syntax checks should not emit a PCH file
       OutputTy = types::TY_Nothing;
     }
-    return llvm::make_unique<PrecompileJobAction>(std::move(Input), OutputTy);
+    return C.MakeAction<PrecompileJobAction>(Input, OutputTy);
   }
   case phases::Compile: {
     if (Args.hasArg(options::OPT_fsyntax_only))
-      return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                                 types::TY_Nothing);
+      return C.MakeAction<CompileJobAction>(Input, types::TY_Nothing);
     if (Args.hasArg(options::OPT_rewrite_objc))
-      return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                                 types::TY_RewrittenObjC);
+      return C.MakeAction<CompileJobAction>(Input, types::TY_RewrittenObjC);
     if (Args.hasArg(options::OPT_rewrite_legacy_objc))
-      return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                                 types::TY_RewrittenLegacyObjC);
+      return C.MakeAction<CompileJobAction>(Input,
     if (Args.hasArg(options::OPT__analyze, options::OPT__analyze_auto))
-      return llvm::make_unique<AnalyzeJobAction>(std::move(Input),
-                                                 types::TY_Plist);
+      return C.MakeAction<AnalyzeJobAction>(Input, types::TY_Plist);
     if (Args.hasArg(options::OPT__migrate))
-      return llvm::make_unique<MigrateJobAction>(std::move(Input),
-                                                 types::TY_Remap);
+      return C.MakeAction<MigrateJobAction>(Input, types::TY_Remap);
     if (Args.hasArg(options::OPT_emit_ast))
-      return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                                 types::TY_AST);
+      return C.MakeAction<CompileJobAction>(Input, types::TY_AST);
     if (Args.hasArg(options::OPT_module_file_info))
-      return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                                 types::TY_ModuleFile);
+      return C.MakeAction<CompileJobAction>(Input, types::TY_ModuleFile);
     if (Args.hasArg(options::OPT_verify_pch))
-      return llvm::make_unique<VerifyPCHJobAction>(std::move(Input),
-                                                   types::TY_Nothing);
-    return llvm::make_unique<CompileJobAction>(std::move(Input),
-                                               types::TY_LLVM_BC);
+      return C.MakeAction<VerifyPCHJobAction>(Input, types::TY_Nothing);
+    return C.MakeAction<CompileJobAction>(Input, types::TY_LLVM_BC);
   }
   case phases::Backend: {
     if (isUsingLTO()) {
       types::ID Output =
           Args.hasArg(options::OPT_S) ? types::TY_LTO_IR : types::TY_LTO_BC;
-      return llvm::make_unique<BackendJobAction>(std::move(Input), Output);
+      return C.MakeAction<BackendJobAction>(Input, Output);
     }
     if (Args.hasArg(options::OPT_emit_llvm)) {
       types::ID Output =
           Args.hasArg(options::OPT_S) ? types::TY_LLVM_IR : types::TY_LLVM_BC;
-      return llvm::make_unique<BackendJobAction>(std::move(Input), Output);
+      return C.MakeAction<BackendJobAction>(Input, Output);
     }
-    return llvm::make_unique<BackendJobAction>(std::move(Input),
-                                               types::TY_PP_Asm);
+    return C.MakeAction<BackendJobAction>(Input, types::TY_PP_Asm);
   }
   case phases::Assemble:
-    return llvm::make_unique<AssembleJobAction>(std::move(Input),
-                                                types::TY_Object);
+    return C.MakeAction<AssembleJobAction>(Input, types::TY_Object);
   }
 
   llvm_unreachable("invalid phase in ConstructPhaseAction");
 }
 
 void Driver::BuildJobs(Compilation &C) const {
   llvm::PrettyStackTraceString CrashInfo("Building compilation jobs");