Merge pull request #27417 from atrick/cleanup-cfg-utils

Author: swift-ci

include/swift/SIL/OptimizationRemark.h

@@ -157,9 +157,9 @@ class Emitter {
     using RemarkT = decltype(RemarkBuilder());
     // Avoid building the remark unless remarks are enabled.
     if (isEnabled<RemarkT>() || Module.getOptRecordStream()) {
-      auto R = RemarkBuilder();
-      R.setPassName(PassName);
-      emit(R);
+      auto rb = RemarkBuilder();
+      rb.setPassName(PassName);
+      emit(rb);
     }
   }
 

include/swift/SIL/SILInstructionWorklist.h

@@ -33,7 +33,7 @@
 #include "swift/Basic/BlotSetVector.h"
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILValue.h"
-#include "swift/SILOptimizer/Utils/Local.h"
+#include "swift/SILOptimizer/Utils/InstOptUtils.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 

include/swift/SIL/TypeSubstCloner.h

@@ -21,10 +21,10 @@
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/Type.h"
-#include "swift/SIL/SILCloner.h"
 #include "swift/SIL/DynamicCasts.h"
+#include "swift/SIL/SILCloner.h"
 #include "swift/SIL/SILFunctionBuilder.h"
-#include "swift/SILOptimizer/Utils/Local.h"
+#include "swift/SILOptimizer/Utils/InstOptUtils.h"
 #include "swift/SILOptimizer/Utils/SpecializationMangler.h"
 #include "llvm/Support/Debug.h"
 

include/swift/SILOptimizer/Analysis/CFG.h

@@ -17,7 +17,7 @@
 #include "swift/SIL/SILInstruction.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SILOptimizer/Analysis/Analysis.h"
-#include "swift/SILOptimizer/Utils/Local.h"
+#include "swift/SILOptimizer/Utils/InstOptUtils.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallSet.h"

include/swift/SILOptimizer/Analysis/CallerAnalysis.h

@@ -0,0 +1,260 @@
+//===--- BasicBlockOptUtils.h - SIL basic block utilities -------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// Utilities used by the SILOptimizer for analyzing and operating on whole
+/// basic blocks, including as removal, cloning, and SSA update.
+///
+/// CFGOptUtils.h provides lower-level CFG branch and edge utilities.
+///
+/// SIL/BasicBlockUtils.h provides essential SILBasicBlock utilities.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SILOPTIMIZER_UTILS_BASICBLOCKOPTUTILS_H
+#define SWIFT_SILOPTIMIZER_UTILS_BASICBLOCKOPTUTILS_H
+
+#include "swift/SIL/SILInstruction.h"
+#include "swift/SIL/SILBasicBlock.h"
+#include "swift/SIL/SILCloner.h"
+
+namespace swift {
+
+class BasicBlockCloner;
+class SILLoop;
+class SILLoopInfo;
+
+/// Remove all instructions in the body of \p bb in safe manner by using
+/// undef.
+void clearBlockBody(SILBasicBlock *bb);
+
+/// Handle the mechanical aspects of removing an unreachable block.
+void removeDeadBlock(SILBasicBlock *bb);
+
+/// Remove all unreachable blocks in a function.
+bool removeUnreachableBlocks(SILFunction &f);
+
+/// Return true if there are any users of v outside the specified block.
+inline bool isUsedOutsideOfBlock(SILValue v) {
+  auto *bb = v->getParentBlock();
+  for (auto *use : v->getUses())
+    if (use->getUser()->getParent() != bb)
+      return true;
+  return false;
+}
+
+/// Rotate a loop's header as long as it is exiting and not equal to the
+/// passed basic block.
+/// If \p RotateSingleBlockLoops is true a single basic block loop will be
+/// rotated once. ShouldVerify specifies whether to perform verification after
+/// the transformation.
+/// Returns true if the loop could be rotated.
+bool rotateLoop(SILLoop *loop, DominanceInfo *domInfo, SILLoopInfo *loopInfo,
+                bool rotateSingleBlockLoops, SILBasicBlock *upToBB,
+                bool shouldVerify);
+
+/// Helper function to perform SSA updates in case of jump threading.
+void updateSSAAfterCloning(BasicBlockCloner &cloner, SILBasicBlock *srcBB,
+                           SILBasicBlock *destBB);
+
+/// Clone a single basic block and any required successor edges within the same
+/// function.
+class BasicBlockCloner : public SILCloner<BasicBlockCloner> {
+  using SuperTy = SILCloner<BasicBlockCloner>;
+  friend class SILCloner<BasicBlockCloner>;
+
+protected:
+  /// The original block to be cloned.
+  SILBasicBlock *origBB;
+
+public:
+  /// An ordered list of old to new available value pairs.
+  ///
+  /// updateSSAAfterCloning() expects this public field to hold values that may
+  /// be remapped in the cloned block and live out.
+  SmallVector<std::pair<SILValue, SILValue>, 16> AvailVals;
+
+  // Clone blocks starting at `origBB`, within the same function.
+  BasicBlockCloner(SILBasicBlock *origBB)
+      : SILCloner(*origBB->getParent()), origBB(origBB) {}
+
+  void cloneBlock(SILBasicBlock *insertAfterBB = nullptr) {
+    SmallVector<SILBasicBlock *, 4> successorBBs;
+    successorBBs.reserve(origBB->getSuccessors().size());
+    llvm::copy(origBB->getSuccessors(), std::back_inserter(successorBBs));
+    cloneReachableBlocks(origBB, successorBBs, insertAfterBB);
+  }
+
+  /// Clone the given branch instruction's destination block, splitting
+  /// its successors, and rewrite the branch instruction.
+  void cloneBranchTarget(BranchInst *bi) {
+    assert(origBB == bi->getDestBB());
+
+    cloneBlock(/*insertAfter*/ bi->getParent());
+
+    SILBuilderWithScope(bi).createBranch(bi->getLoc(), getNewBB(),
+                                         bi->getArgs());
+    bi->eraseFromParent();
+  }
+
+  /// Get the newly cloned block corresponding to `origBB`.
+  SILBasicBlock *getNewBB() {
+    return remapBasicBlock(origBB);
+  }
+
+  /// Call this after processing all instructions to fix the control flow
+  /// graph. The branch cloner may have left critical edges.
+  bool splitCriticalEdges(DominanceInfo *domInfo, SILLoopInfo *loopInfo);
+
+protected:
+  // MARK: CRTP overrides.
+
+  /// Override getMappedValue to allow values defined outside the block to be
+  /// cloned to be reused in the newly cloned block.
+  SILValue getMappedValue(SILValue value) {
+    if (auto si = value->getDefiningInstruction()) {
+      if (!isBlockCloned(si->getParent()))
+        return value;
+    } else if (auto bbArg = dyn_cast<SILArgument>(value)) {
+      if (!isBlockCloned(bbArg->getParent()))
+        return value;
+    } else {
+      assert(isa<SILUndef>(value) && "Unexpected Value kind");
+      return value;
+    }
+    // `value` is not defined outside the cloned block, so consult the cloner's
+    // map of cloned values.
+    return SuperTy::getMappedValue(value);
+  }
+
+  void mapValue(SILValue origValue, SILValue mappedValue) {
+    SuperTy::mapValue(origValue, mappedValue);
+    AvailVals.emplace_back(origValue, mappedValue);
+  }
+};
+
+// Helper class that provides a callback that can be used in
+// inliners/cloners for collecting new call sites.
+class CloneCollector {
+public:
+  typedef std::pair<SILInstruction *, SILInstruction *> value_type;
+  typedef std::function<void(SILInstruction *, SILInstruction *)> CallbackType;
+  typedef std::function<bool (SILInstruction *)> FilterType;
+
+private:
+  FilterType filter;
+
+  // Pairs of collected instructions; (new, old)
+  llvm::SmallVector<value_type, 4> instructionpairs;
+
+  void collect(SILInstruction *oldI, SILInstruction *newI) {
+    if (filter(newI))
+      instructionpairs.push_back(std::make_pair(newI, oldI));
+  }
+
+public:
+  CloneCollector(FilterType filter) : filter(filter) {}
+
+  CallbackType getCallback() {
+    return std::bind(&CloneCollector::collect, this, std::placeholders::_1,
+                     std::placeholders::_2);
+  }
+
+  llvm::SmallVectorImpl<value_type> &getInstructionPairs() {
+    return instructionpairs;
+  }
+};
+
+/// Sink address projections to their out-of-block uses. This is
+/// required after cloning a block and before calling
+/// updateSSAAfterCloning to avoid address-type phis.
+///
+/// This clones address projections at their use points, but does not
+/// mutate the block containing the projections.
+class SinkAddressProjections {
+  // Projections ordered from last to first in the chain.
+  SmallVector<SingleValueInstruction *, 4> projections;
+  SmallSetVector<SILValue, 4> inBlockDefs;
+
+public:
+  /// Check for an address projection chain ending at \p inst. Return true if
+  /// the given instruction is successfully analyzed.
+  ///
+  /// If \p inst does not produce an address, then return
+  /// true. getInBlockDefs() will contain \p inst if any of its
+  /// (non-address) values are used outside its block.
+  ///
+  /// If \p inst does produce an address, return true only of the
+  /// chain of address projections within this block is clonable at
+  /// their use sites. getInBlockDefs will return all non-address
+  /// operands in the chain that are also defined in this block. These
+  /// may require phis after cloning the projections.
+  bool analyzeAddressProjections(SILInstruction *inst);
+
+  /// After analyzing projections, returns the list of (non-address) values
+  /// defined in the same block as the projections which will have uses outside
+  /// the block after cloning.
+  ArrayRef<SILValue> getInBlockDefs() const {
+    return inBlockDefs.getArrayRef();
+  }
+  /// Clone the chain of projections at their use sites.
+  ///
+  /// Return true if anything was done.
+  ///
+  /// getInBlockProjectionOperandValues() can be called before or after cloning.
+  bool cloneProjections();
+};
+
+/// Utility class for cloning init values into the static initializer of a
+/// SILGlobalVariable.
+class StaticInitCloner : public SILCloner<StaticInitCloner> {
+  friend class SILInstructionVisitor<StaticInitCloner>;
+  friend class SILCloner<StaticInitCloner>;
+
+  /// The number of not yet cloned operands for each instruction.
+  llvm::DenseMap<SILInstruction *, int> numOpsToClone;
+
+  /// List of instructions for which all operands are already cloned (or which
+  /// don't have any operands).
+  llvm::SmallVector<SILInstruction *, 8> readyToClone;
+
+public:
+  StaticInitCloner(SILGlobalVariable *gVar)
+      : SILCloner<StaticInitCloner>(gVar) {}
+
+  /// Add \p InitVal and all its operands (transitively) for cloning.
+  ///
+  /// Note: all init values must are added, before calling clone().
+  void add(SILInstruction *initVal);
+
+  /// Clone \p InitVal and all its operands into the initializer of the
+  /// SILGlobalVariable.
+  ///
+  /// \return Returns the cloned instruction in the SILGlobalVariable.
+  SingleValueInstruction *clone(SingleValueInstruction *initVal);
+
+  /// Convenience function to clone a single \p InitVal.
+  static void appendToInitializer(SILGlobalVariable *gVar,
+                                  SingleValueInstruction *initVal) {
+    StaticInitCloner cloner(gVar);
+    cloner.add(initVal);
+    cloner.clone(initVal);
+  }
+
+protected:
+  SILLocation remapLocation(SILLocation loc) {
+    return ArtificialUnreachableLocation();
+  }
+};
+
+} // namespace swift
+
+#endif