[PM] Separate the LoopAnalysisManager from the LoopPassManager and move

the latter to the Transforms library.

While the loop PM uses an analysis to form the IR units, the current
plan is to have the PM itself establish and enforce both loop simplified
form and LCSSA. This would be a layering violation in the analysis
library.

Fundamentally, the idea behind the loop PM is to *transform* loops in
addition to running passes over them, so it really seemed like the most
natural place to sink this was into the transforms library.

We can't just move *everything* because we also have loop analyses that
rely on a subset of the invariants. So this patch splits the the loop
infrastructure into the analysis management that has to be part of the
analysis library, and the transform-aware pass manager.

This also required splitting the loop analyses' printer passes out to
the transforms library, which makes sense to me as running these will
transform the code into LCSSA in theory.

I haven't split the unittest though because testing one component
without the other seems nearly intractable.

Differential Revision: https://reviews.llvm.org/D28452

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291662 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/IVUsers.h

@@ -15,8 +15,8 @@
 #ifndef LLVM_ANALYSIS_IVUSERS_H
 #define LLVM_ANALYSIS_IVUSERS_H
 
+#include "llvm/Analysis/LoopAnalysisManager.h"
 #include "llvm/Analysis/LoopPass.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/Analysis/ScalarEvolutionNormalization.h"
 #include "llvm/IR/ValueHandle.h"
 
@@ -197,15 +197,6 @@ class IVUsersAnalysis : public AnalysisInfoMixin<IVUsersAnalysis> {
               LoopStandardAnalysisResults &AR);
 };
 
-/// Printer pass for the \c IVUsers for a loop.
-class IVUsersPrinterPass : public PassInfoMixin<IVUsersPrinterPass> {
-  raw_ostream &OS;
-
-public:
-  explicit IVUsersPrinterPass(raw_ostream &OS) : OS(OS) {}
-  PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
-                        LoopStandardAnalysisResults &AR, LPMUpdater &U);
-};
 }
 
 #endif

include/llvm/Analysis/LoopAccessAnalysis.h

@@ -20,7 +20,7 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AliasSetTracker.h"
-#include "llvm/Analysis/LoopPassManager.h"
+#include "llvm/Analysis/LoopAnalysisManager.h"
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/ValueHandle.h"
@@ -757,17 +757,6 @@ class LoopAccessAnalysis
   Result run(Loop &L, LoopAnalysisManager &AM, LoopStandardAnalysisResults &AR);
 };
 
-/// \brief Printer pass for the \c LoopAccessInfo results.
-class LoopAccessInfoPrinterPass
-    : public PassInfoMixin<LoopAccessInfoPrinterPass> {
-  raw_ostream &OS;
-
-public:
-  explicit LoopAccessInfoPrinterPass(raw_ostream &OS) : OS(OS) {}
-  PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
-                        LoopStandardAnalysisResults &AR, LPMUpdater &U);
-};
-
 inline Instruction *MemoryDepChecker::Dependence::getSource(
     const LoopAccessInfo &LAI) const {
   return LAI.getDepChecker().getMemoryInstructions()[Source];

include/llvm/Analysis/LoopAnalysisManager.h

@@ -0,0 +1,155 @@
+//===- LoopAnalysisManager.h - Loop analysis management ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// This header provides classes for managing per-loop analyses. These are
+/// typically used as part of a loop pass pipeline over the loop nests of
+/// a function.
+///
+/// Loop analyses are allowed to make some simplifying assumptions:
+/// 1) Loops are, where possible, in simplified form.
+/// 2) Loops are *always* in LCSSA form.
+/// 3) A collection of analysis results are available:
+///    - LoopInfo
+///    - DominatorTree
+///    - ScalarEvolution
+///    - AAManager
+///
+/// The primary mechanism to provide these invariants is the loop pass manager,
+/// but they can also be manually provided in order to reason about a loop from
+/// outside of a dedicated pass manager.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_LOOPANALYSISMANAGER_H
+#define LLVM_ANALYSIS_LOOPANALYSISMANAGER_H
+
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/PriorityWorklist.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/BasicAliasAnalysis.h"
+#include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// The adaptor from a function pass to a loop pass computes these analyses and
+/// makes them available to the loop passes "for free". Each loop pass is
+/// expected expected to update these analyses if necessary to ensure they're
+/// valid after it runs.
+struct LoopStandardAnalysisResults {
+  AAResults &AA;
+  AssumptionCache ∾
+  DominatorTree &DT;
+  LoopInfo &LI;
+  ScalarEvolution &SE;
+  TargetLibraryInfo &TLI;
+  TargetTransformInfo &TTI;
+};
+
+/// Extern template declaration for the analysis set for this IR unit.
+extern template class AllAnalysesOn<Loop>;
+
+extern template class AnalysisManager<Loop, LoopStandardAnalysisResults &>;
+/// \brief The loop analysis manager.
+///
+/// See the documentation for the AnalysisManager template for detail
+/// documentation. This typedef serves as a convenient way to refer to this
+/// construct in the adaptors and proxies used to integrate this into the larger
+/// pass manager infrastructure.
+typedef AnalysisManager<Loop, LoopStandardAnalysisResults &>
+    LoopAnalysisManager;
+
+/// A proxy from a \c LoopAnalysisManager to a \c Function.
+typedef InnerAnalysisManagerProxy<LoopAnalysisManager, Function>
+    LoopAnalysisManagerFunctionProxy;
+
+/// A specialized result for the \c LoopAnalysisManagerFunctionProxy which
+/// retains a \c LoopInfo reference.
+///
+/// This allows it to collect loop objects for which analysis results may be
+/// cached in the \c LoopAnalysisManager.
+template <> class LoopAnalysisManagerFunctionProxy::Result {
+public:
+  explicit Result(LoopAnalysisManager &InnerAM, LoopInfo &LI)
+      : InnerAM(&InnerAM), LI(&LI) {}
+  Result(Result &&Arg) : InnerAM(std::move(Arg.InnerAM)), LI(Arg.LI) {
+    // We have to null out the analysis manager in the moved-from state
+    // because we are taking ownership of the responsibilty to clear the
+    // analysis state.
+    Arg.InnerAM = nullptr;
+  }
+  Result &operator=(Result &&RHS) {
+    InnerAM = RHS.InnerAM;
+    LI = RHS.LI;
+    // We have to null out the analysis manager in the moved-from state
+    // because we are taking ownership of the responsibilty to clear the
+    // analysis state.
+    RHS.InnerAM = nullptr;
+    return *this;
+  }
+  ~Result() {
+    // InnerAM is cleared in a moved from state where there is nothing to do.
+    if (!InnerAM)
+      return;
+
+    // Clear out the analysis manager if we're being destroyed -- it means we
+    // didn't even see an invalidate call when we got invalidated.
+    InnerAM->clear();
+  }
+
+  /// Accessor for the analysis manager.
+  LoopAnalysisManager &getManager() { return *InnerAM; }
+
+  /// Handler for invalidation of the proxy for a particular function.
+  ///
+  /// If the proxy, \c LoopInfo, and associated analyses are preserved, this
+  /// will merely forward the invalidation event to any cached loop analysis
+  /// results for loops within this function.
+  ///
+  /// If the necessary loop infrastructure is not preserved, this will forcibly
+  /// clear all of the cached analysis results that are keyed on the \c
+  /// LoopInfo for this function.
+  bool invalidate(Function &F, const PreservedAnalyses &PA,
+                  FunctionAnalysisManager::Invalidator &Inv);
+
+private:
+  LoopAnalysisManager *InnerAM;
+  LoopInfo *LI;
+};
+
+/// Provide a specialized run method for the \c LoopAnalysisManagerFunctionProxy
+/// so it can pass the \c LoopInfo to the result.
+template <>
+LoopAnalysisManagerFunctionProxy::Result
+LoopAnalysisManagerFunctionProxy::run(Function &F, FunctionAnalysisManager &AM);
+
+// Ensure the \c LoopAnalysisManagerFunctionProxy is provided as an extern
+// template.
+extern template class InnerAnalysisManagerProxy<LoopAnalysisManager, Function>;
+
+extern template class OuterAnalysisManagerProxy<FunctionAnalysisManager, Loop,
+                                                LoopStandardAnalysisResults &>;
+/// A proxy from a \c FunctionAnalysisManager to a \c Loop.
+typedef OuterAnalysisManagerProxy<FunctionAnalysisManager, Loop,
+                                  LoopStandardAnalysisResults &>
+    FunctionAnalysisManagerLoopProxy;
+
+/// Returns the minimum set of Analyses that all loop passes must preserve.
+PreservedAnalyses getLoopPassPreservedAnalyses();
+}
+
+#endif // LLVM_ANALYSIS_LOOPANALYSISMANAGER_H

include/llvm/Passes/PassBuilder.h

@@ -18,8 +18,8 @@
 
 #include "llvm/ADT/Optional.h"
 #include "llvm/Analysis/CGSCCPassManager.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 #include <vector>
 
 namespace llvm {

include/llvm/Transforms/Scalar/IVUsersPrinter.h

@@ -0,0 +1,30 @@
+//===- IVUsersPrinter.h - Induction Variable Users Printing -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_IVUSERSPRINTER_H
+#define LLVM_TRANSFORMS_SCALAR_IVUSERSPRINTER_H
+
+#include "llvm/Analysis/IVUsers.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
+
+namespace llvm {
+
+/// Printer pass for the \c IVUsers for a loop.
+class IVUsersPrinterPass : public PassInfoMixin<IVUsersPrinterPass> {
+  raw_ostream &OS;
+
+public:
+  explicit IVUsersPrinterPass(raw_ostream &OS) : OS(OS) {}
+  PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
+                        LoopStandardAnalysisResults &AR, LPMUpdater &U);
+};
+}
+
+#endif

include/llvm/Transforms/Scalar/IndVarSimplify.h

@@ -16,8 +16,8 @@
 #define LLVM_TRANSFORMS_SCALAR_INDVARSIMPLIFY_H
 
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 
 namespace llvm {
 

include/llvm/Transforms/Scalar/LICM.h

@@ -34,8 +34,8 @@
 #define LLVM_TRANSFORMS_SCALAR_LICM_H
 
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 
 namespace llvm {
 

include/llvm/Transforms/Scalar/LoopAccessAnalysisPrinter.h

@@ -0,0 +1,31 @@
+//===- llvm/Analysis/LoopAccessAnalysisPrinter.h ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_LOOPACCESSANALYSISPRINTER_H
+#define LLVM_TRANSFORMS_SCALAR_LOOPACCESSANALYSISPRINTER_H
+
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
+
+namespace llvm {
+
+/// \brief Printer pass for the \c LoopAccessInfo results.
+class LoopAccessInfoPrinterPass
+    : public PassInfoMixin<LoopAccessInfoPrinterPass> {
+  raw_ostream &OS;
+
+public:
+  explicit LoopAccessInfoPrinterPass(raw_ostream &OS) : OS(OS) {}
+  PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
+                        LoopStandardAnalysisResults &AR, LPMUpdater &U);
+};
+
+} // End llvm namespace
+
+#endif

include/llvm/Transforms/Scalar/LoopDeletion.h

@@ -15,9 +15,9 @@
 #define LLVM_TRANSFORMS_SCALAR_LOOPDELETION_H
 
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 
 namespace llvm {
 

include/llvm/Transforms/Scalar/LoopIdiomRecognize.h

@@ -17,8 +17,8 @@
 #define LLVM_TRANSFORMS_SCALAR_LOOPIDIOMRECOGNIZE_H
 
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 
 namespace llvm {
 

include/llvm/Transforms/Scalar/LoopInstSimplify.h

@@ -15,8 +15,8 @@
 #define LLVM_TRANSFORMS_SCALAR_LOOPINSTSIMPLIFY_H
 
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPassManager.h"
 #include "llvm/IR/PassManager.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 
 namespace llvm {