Revert r238305: [PM] Use a simpler technique to drop optional analysis

manager arguments...

I have no idea why, but compilers seem to hate this and its late, so I'm
not going to debug it. :: sigh :: This is why we can't have nice things.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238306 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/PassManagerInternal.h

@@ -29,56 +29,41 @@ class PreservedAnalyses;
 /// \brief Implementation details of the pass manager interfaces.
 namespace detail {
 
-/// \brief Helper template to run a pass *with* an optional analysis manager.
-///
-/// This accepts the address of the run method as an argument to detect that it
-/// accepts the analysis manager and pass it through. This isn't (quite)
-/// a generic optional argument invocation tool, and couldn't be without making
-/// the calling syntax significantly more verbose.
-template <typename ResultT, typename IRUnitT, typename PassT>
-ResultT invokeRunMethod(PassT &Pass,
-                        ResultT (PassT::*run)(IRUnitT &,
-                                              AnalysisManager<IRUnitT> *),
-                        IRUnitT &IR, AnalysisManager<IRUnitT> *AM) {
-  return (Pass.*run)(IR, AM);
-}
-
-/// \brief Helper template to run a pass *without* an optional analysis manager.
-///
-/// This accepts the address of the run method as an argument to detect that it
-/// does not accept an analysis manager and drop it. This isn't (quite)
-/// a generic optional argument invocation tool, and couldn't be without making
-/// the calling syntax significantly more verbose.
-template <typename ResultT, typename IRUnitT, typename PassT>
-ResultT invokeRunMethod(
-    PassT &Pass,
-    ResultT (PassT::*run)(IRUnitT &),
-    IRUnitT &IR, AnalysisManager<IRUnitT> * /*AM*/) {
-  return (Pass.*run)(IR);
-}
-
 /// \brief Template for the abstract base class used to dispatch
 /// polymorphically over pass objects.
-template <typename ResultT, typename IRUnitT> struct PassConceptBase {
+template <typename IRUnitT> struct PassConcept {
-  virtual ~PassConceptBase() {}
+  // Boiler plate necessary for the container of derived classes.
+  virtual ~PassConcept() {}
 
   /// \brief The polymorphic API which runs the pass over a given IR entity.
   ///
   /// Note that actual pass object can omit the analysis manager argument if
   /// desired. Also that the analysis manager may be null if there is no
   /// analysis manager in the pass pipeline.
-  virtual ResultT run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) = 0;
+  virtual PreservedAnalyses run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) = 0;
 
   /// \brief Polymorphic method to access the name of a pass.
   virtual StringRef name() = 0;
 };
 
-/// \brief Abstract concept of an transform pass.
+/// \brief SFINAE metafunction for computing whether \c PassT has a run method
-///
+/// accepting an \c AnalysisManager<IRUnitT>.
-/// This concept is parameterized over the IR unit that it can run over and
+template <typename IRUnitT, typename PassT, typename ResultT>
-/// returns status of preserved analyses.
+class PassRunAcceptsAnalysisManager {
-template <typename IRUnitT>
+  typedef char SmallType;
-using PassConcept = PassConceptBase<PreservedAnalyses, IRUnitT>;
+  struct BigType {
+    char a, b;
+  };
+
+  template <typename T, ResultT (T::*)(IRUnitT &, AnalysisManager<IRUnitT> *)>
+  struct Checker;
+
+  template <typename T> static SmallType f(Checker<T, &T::run> *);
+  template <typename T> static BigType f(...);
+
+public:
+  enum { Value = sizeof(f<PassT>(nullptr)) == sizeof(SmallType) };
+};
 
 /// \brief A template wrapper used to implement the polymorphic API.
 ///
@@ -87,8 +72,16 @@ using PassConcept = PassConceptBase<PreservedAnalyses, IRUnitT>;
 /// \c run method also accepts an \c AnalysisManager<IRUnitT>*, we pass it
 /// along.
 template <typename IRUnitT, typename PassT,
-          typename PreservedAnalysesT = PreservedAnalyses>
+          typename PreservedAnalysesT = PreservedAnalyses,
-struct PassModel : PassConcept<IRUnitT> {
+          bool AcceptsAnalysisManager = PassRunAcceptsAnalysisManager<
+              IRUnitT, PassT, PreservedAnalysesT>::Value>
+struct PassModel;
+
+/// \brief Specialization of \c PassModel for passes that accept an analyis
+/// manager.
+template <typename IRUnitT, typename PassT, typename PreservedAnalysesT>
+struct PassModel<IRUnitT, PassT, PreservedAnalysesT, true>
+    : PassConcept<IRUnitT> {
   explicit PassModel(PassT Pass) : Pass(std::move(Pass)) {}
   // We have to explicitly define all the special member functions because MSVC
   // refuses to generate them.
@@ -103,9 +96,34 @@ struct PassModel : PassConcept<IRUnitT> {
     return *this;
   }
 
-  /// \brief The model delegates to the \c PassT::run method.
   PreservedAnalysesT run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) override {
-    return invokeRunMethod<PreservedAnalysesT>(Pass, &PassT::run, IR, AM);
+    return Pass.run(IR, AM);
+  }
+  StringRef name() override { return PassT::name(); }
+  PassT Pass;
+};
+
+/// \brief Specialization of \c PassModel for passes that accept an analyis
+/// manager.
+template <typename IRUnitT, typename PassT, typename PreservedAnalysesT>
+struct PassModel<IRUnitT, PassT, PreservedAnalysesT, false>
+    : PassConcept<IRUnitT> {
+  explicit PassModel(PassT Pass) : Pass(std::move(Pass)) {}
+  // We have to explicitly define all the special member functions because MSVC
+  // refuses to generate them.
+  PassModel(const PassModel &Arg) : Pass(Arg.Pass) {}
+  PassModel(PassModel &&Arg) : Pass(std::move(Arg.Pass)) {}
+  friend void swap(PassModel &LHS, PassModel &RHS) {
+    using std::swap;
+    swap(LHS.Pass, RHS.Pass);
+  }
+  PassModel &operator=(PassModel RHS) {
+    swap(*this, RHS);
+    return *this;
+  }
+
+  PreservedAnalysesT run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) override {
+    return Pass.run(IR);
   }
   StringRef name() override { return PassT::name(); }
   PassT Pass;
@@ -227,17 +245,33 @@ struct AnalysisResultModel<IRUnitT, PassT, ResultT, PreservedAnalysesT, true>
 ///
 /// This concept is parameterized over the IR unit that it can run over and
 /// produce an analysis result.
-template <typename IRUnitT>
+template <typename IRUnitT> struct AnalysisPassConcept {
-using AnalysisPassConcept =
+  virtual ~AnalysisPassConcept() {}
-    PassConceptBase<std::unique_ptr<AnalysisResultConcept<IRUnitT>>, IRUnitT>;
+
+  /// \brief Method to run this analysis over a unit of IR.
+  /// \returns A unique_ptr to the analysis result object to be queried by
+  /// users.
+  virtual std::unique_ptr<AnalysisResultConcept<IRUnitT>>
+  run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) = 0;
+
+  /// \brief Polymorphic method to access the name of a pass.
+  virtual StringRef name() = 0;
+};
 
 /// \brief Wrapper to model the analysis pass concept.
 ///
 /// Can wrap any type which implements a suitable \c run method. The method
 /// must accept the IRUnitT as an argument and produce an object which can be
 /// wrapped in a \c AnalysisResultModel.
+template <typename IRUnitT, typename PassT,
+          bool AcceptsAnalysisManager = PassRunAcceptsAnalysisManager<
+              IRUnitT, PassT, typename PassT::Result>::Value>
+struct AnalysisPassModel;
+
+/// \brief Specialization of \c AnalysisPassModel which passes an
+/// \c AnalysisManager to PassT's run method.
 template <typename IRUnitT, typename PassT>
-struct AnalysisPassModel : AnalysisPassConcept<IRUnitT> {
+struct AnalysisPassModel<IRUnitT, PassT, true> : AnalysisPassConcept<IRUnitT> {
   explicit AnalysisPassModel(PassT Pass) : Pass(std::move(Pass)) {}
   // We have to explicitly define all the special member functions because MSVC
   // refuses to generate them.
@@ -253,16 +287,53 @@ struct AnalysisPassModel : AnalysisPassConcept<IRUnitT> {
   }
 
   // FIXME: Replace PassT::Result with type traits when we use C++11.
-  using ResultT = typename PassT::Result;
+  typedef AnalysisResultModel<IRUnitT, PassT, typename PassT::Result>
-  using ResultModelT = AnalysisResultModel<IRUnitT, PassT, ResultT>;
+      ResultModelT;
 
   /// \brief The model delegates to the \c PassT::run method.
   ///
   /// The return is wrapped in an \c AnalysisResultModel.
   std::unique_ptr<AnalysisResultConcept<IRUnitT>>
   run(IRUnitT &IR, AnalysisManager<IRUnitT> *AM) override {
-    return make_unique<ResultModelT>(
+    return make_unique<ResultModelT>(Pass.run(IR, AM));
-        invokeRunMethod<ResultT>(Pass, &PassT::run, IR, AM));
+  }
+
+  /// \brief The model delegates to a static \c PassT::name method.
+  ///
+  /// The returned string ref must point to constant immutable data!
+  StringRef name() override { return PassT::name(); }
+
+  PassT Pass;
+};
+
+/// \brief Specialization of \c AnalysisPassModel which does not pass an
+/// \c AnalysisManager to PassT's run method.
+template <typename IRUnitT, typename PassT>
+struct AnalysisPassModel<IRUnitT, PassT, false> : AnalysisPassConcept<IRUnitT> {
+  explicit AnalysisPassModel(PassT Pass) : Pass(std::move(Pass)) {}
+  // We have to explicitly define all the special member functions because MSVC
+  // refuses to generate them.
+  AnalysisPassModel(const AnalysisPassModel &Arg) : Pass(Arg.Pass) {}
+  AnalysisPassModel(AnalysisPassModel &&Arg) : Pass(std::move(Arg.Pass)) {}
+  friend void swap(AnalysisPassModel &LHS, AnalysisPassModel &RHS) {
+    using std::swap;
+    swap(LHS.Pass, RHS.Pass);
+  }
+  AnalysisPassModel &operator=(AnalysisPassModel RHS) {
+    swap(*this, RHS);
+    return *this;
+  }
+
+  // FIXME: Replace PassT::Result with type traits when we use C++11.
+  typedef AnalysisResultModel<IRUnitT, PassT, typename PassT::Result>
+      ResultModelT;
+
+  /// \brief The model delegates to the \c PassT::run method.
+  ///
+  /// The return is wrapped in an \c AnalysisResultModel.
+  std::unique_ptr<AnalysisResultConcept<IRUnitT>>
+  run(IRUnitT &IR, AnalysisManager<IRUnitT> *) override {
+    return make_unique<ResultModelT>(Pass.run(IR));
   }
 
   /// \brief The model delegates to a static \c PassT::name method.