[NFC] CanOSSALifetime: Break up rewriteCopies.

Add a helper class and promote a lambda to member of it.

Author: nate-chandler

include/swift/SILOptimizer/Utils/CanonicalizeOSSALifetime.h

@@ -452,6 +452,8 @@ class CanonicalizeOSSALifetime final {
   void insertDestroysOnBoundary(PrunedLivenessBoundary const &boundary);
 
   void rewriteCopies();
+  class RewriteCopies;
+  friend class RewriteCopies;
 };
 
 } // end namespace swift

lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp

@@ -1038,57 +1038,78 @@ void swift::copyLiveUse(Operand *use, InstModCallbacks &instModCallbacks) {
   LLVM_DEBUG(llvm::dbgs() << "  Copying at last use " << *copy);
 }
 
-/// Revisit the def-use chain of currentDef. Mark unneeded original
-/// copies and destroys for deletion. Insert new copies for interior uses that
-/// require ownership of the used operand.
-void CanonicalizeOSSALifetime::rewriteCopies() {
-  assert(getCurrentDef()->getOwnershipKind() == OwnershipKind::Owned);
+class CanonicalizeOSSALifetime::RewriteCopies {
+  CanonicalizeOSSALifetime &canonicalize;
+  SSAPrunedLiveness &liveness;
+  GraphNodeWorklist<SILValue, 8> &defUseWorklist;
+  CanonicalOSSAConsumeInfo &consumes;
+  InstructionDeleter &deleter;
+  InstructionSetVector instsToDelete;
 
-  InstructionSetVector instsToDelete(getCurrentDef()->getFunction());
-  defUseWorklist.clear();
+  SILValue getCurrentDef() { return canonicalize.getCurrentDef(); }
+  InstModCallbacks &getCallbacks() { return deleter.getCallbacks(); }
 
-  // Visit each operand in the def-use chain.
-  //
-  // Return true if the operand can use the current definition. Return false if
-  // it requires a copy.
-  auto visitUse = [&](Operand *use) {
-    auto *user = use->getUser();
-    // Recurse through copies.
-    if (auto *copy = dyn_cast<CopyValueInst>(user)) {
-      defUseWorklist.insert(copy);
-      return true;
-    }
-    if (destroys.contains(user)) {
-      auto *destroy = cast<DestroyValueInst>(user);
-      // If this destroy was marked as a final destroy, ignore it; otherwise,
-      // delete it.
-      if (!consumes.claimConsume(destroy)) {
-        instsToDelete.insert(destroy);
-        LLVM_DEBUG(llvm::dbgs() << "  Removing " << *destroy);
-        ++NumDestroysEliminated;
-      } else if (pruneDebugMode) {
-        // If this destroy was marked as a final destroy, add it to liveness so
-        // that we don't delete any debug instructions that occur before it.
-        // (Only relevant in pruneDebugMode).
-        liveness->updateForUse(destroy, /*lifetimeEnding*/ true);
-      }
-      return true;
-    }
+public:
+  RewriteCopies(CanonicalizeOSSALifetime &canonicalize)
+      : canonicalize(canonicalize), liveness(*canonicalize.liveness),
+        defUseWorklist(canonicalize.defUseWorklist),
+        consumes(canonicalize.consumes), deleter(canonicalize.deleter),
+        instsToDelete(canonicalize.getCurrentDef()->getFunction()) {}
 
-    // Nonconsuming uses do not need copies and cannot be marked as destroys.
-    // A lifetime-ending use here must be a consume because EndBorrow/Reborrow
-    // uses have been filtered out.
-    if (!use->isLifetimeEnding())
-      return true;
+  void rewrite();
 
-    // If this use was not marked as a final destroy *or* this is not the first
-    // consumed operand we visited, then it needs a copy.
-    if (!consumes.claimConsume(user)) {
-      return false;
+private:
+  bool visitUse(Operand *use);
+};
+
+// Visit each operand in the def-use chain.
+//
+// Return true if the operand can use the current definition. Return false if
+// it requires a copy.
+bool CanonicalizeOSSALifetime::RewriteCopies::visitUse(Operand *use) {
+  auto *user = use->getUser();
+  // Recurse through copies.
+  if (auto *copy = dyn_cast<CopyValueInst>(user)) {
+    defUseWorklist.insert(copy);
+    return true;
+  }
+  if (canonicalize.destroys.contains(user)) {
+    auto *destroy = cast<DestroyValueInst>(user);
+    // If this destroy was marked as a final destroy, ignore it; otherwise,
+    // delete it.
+    if (!consumes.claimConsume(destroy)) {
+      instsToDelete.insert(destroy);
+      LLVM_DEBUG(llvm::dbgs() << "  Removing " << *destroy);
+      ++NumDestroysEliminated;
+    } else if (canonicalize.pruneDebugMode) {
+      // If this destroy was marked as a final destroy, add it to liveness so
+      // that we don't delete any debug instructions that occur before it.
+      // (Only relevant in pruneDebugMode).
+      liveness.updateForUse(destroy, /*lifetimeEnding*/ true);
     }
+    return true;
+  }
 
+  // Nonconsuming uses do not need copies and cannot be marked as destroys.
+  // A lifetime-ending use here must be a consume because EndBorrow/Reborrow
+  // uses have been filtered out.
+  if (!use->isLifetimeEnding())
     return true;
-  };
+
+  // If this use was not marked as a final destroy *or* this is not the first
+  // consumed operand we visited, then it needs a copy.
+  if (!consumes.claimConsume(user)) {
+    return false;
+  }
+
+  return true;
+}
+
+/// Revisit the def-use chain of currentDef. Mark unneeded original
+/// copies and destroys for deletion. Insert new copies for interior uses that
+/// require ownership of the used operand.
+void CanonicalizeOSSALifetime::RewriteCopies::rewrite() {
+  defUseWorklist.clear();
 
   // Perform a def-use traversal, visiting each use operand.
   for (auto useIter = getCurrentDef()->use_begin(),
@@ -1126,9 +1147,9 @@ void CanonicalizeOSSALifetime::rewriteCopies() {
   }
   assert(!consumes.hasUnclaimedConsumes());
 
-  if (pruneDebugMode) {
-    for (auto *dvi : debugValues) {
-      if (!liveness->isWithinBoundary(dvi)) {
+  if (canonicalize.pruneDebugMode) {
+    for (auto *dvi : canonicalize.debugValues) {
+      if (!liveness.isWithinBoundary(dvi)) {
         LLVM_DEBUG(llvm::dbgs() << "  Removing debug_value: " << *dvi);
         deleter.forceDelete(dvi);
       }
@@ -1141,6 +1162,12 @@ void CanonicalizeOSSALifetime::rewriteCopies() {
   }
 }
 
+void CanonicalizeOSSALifetime::rewriteCopies() {
+  assert(getCurrentDef()->getOwnershipKind() == OwnershipKind::Owned);
+  RewriteCopies rewriter(*this);
+  rewriter.rewrite();
+}
+
 //===----------------------------------------------------------------------===//
 //                            MARK: Top-Level API
 //===----------------------------------------------------------------------===//