[NFC] LifetimeCompletion: Note boundary kind.

When visiting an availability boundary, note what kind of end is
involved.  For now, there's only one.

Author: nate-chandler

include/swift/SIL/OSSALifetimeCompletion.h

@@ -120,10 +120,15 @@ class OSSALifetimeCompletion {
     DoNotAllowLeaks = false,
   };
 
-  static void
-  visitAvailabilityBoundary(SILValue value, AllowLeaks_t allowLeaks,
-                            const SSAPrunedLiveness &liveness,
-                            llvm::function_ref<void(SILInstruction *)> visit);
+  enum class LifetimeEnd : uint8_t {
+    /// The lifetime ends at the boundary.
+    Boundary,
+  };
+
+  static void visitAvailabilityBoundary(
+      SILValue value, AllowLeaks_t allowLeaks,
+      const SSAPrunedLiveness &liveness,
+      llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit);
 
 protected:
   bool analyzeAndUpdateLifetime(SILValue value, Boundary boundary);

lib/SIL/Utils/OSSALifetimeCompletion.cpp

@@ -58,7 +58,9 @@
 
 using namespace swift;
 
-static SILInstruction *endOSSALifetime(SILValue value, SILBuilder &builder) {
+static SILInstruction *endOSSALifetime(SILValue value,
+                                       OSSALifetimeCompletion::LifetimeEnd end,
+                                       SILBuilder &builder) {
   auto loc =
     RegularLocation::getAutoGeneratedLocation(builder.getInsertionPointLoc());
   if (value->getOwnershipKind() == OwnershipKind::Owned) {
@@ -81,14 +83,16 @@ static bool endLifetimeAtLivenessBoundary(SILValue value,
         != PrunedLiveness::LifetimeEndingUse) {
       changed = true;
       SILBuilderWithScope::insertAfter(lastUser, [value](SILBuilder &builder) {
-        endOSSALifetime(value, builder);
+        endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
+                        builder);
       });
     }
   }
   for (SILBasicBlock *edge : boundary.boundaryEdges) {
     changed = true;
     SILBuilderWithScope builder(edge->begin());
-    endOSSALifetime(value, builder);
+    endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
+                    builder);
   }
   for (SILNode *deadDef : boundary.deadDefs) {
     SILInstruction *next = nullptr;
@@ -99,7 +103,8 @@ static bool endLifetimeAtLivenessBoundary(SILValue value,
     }
     changed = true;
     SILBuilderWithScope builder(next);
-    endOSSALifetime(value, builder);
+    endOSSALifetime(value, OSSALifetimeCompletion::LifetimeEnd::Boundary,
+                    builder);
   }
   return changed;
 }
@@ -151,9 +156,11 @@ class AvailabilityBoundaryVisitor {
   void propagateAvailablity(Result &result);
 
   /// Visit the terminators of blocks on the boundary of availability.
-  void
-  visitAvailabilityBoundary(Result const &result,
-                            llvm::function_ref<void(SILInstruction *)> visit);
+  void visitAvailabilityBoundary(
+      Result const &result,
+      llvm::function_ref<void(SILInstruction *,
+                              OSSALifetimeCompletion::LifetimeEnd)>
+          visit);
 
   struct State {
     enum Value : uint8_t {
@@ -300,7 +307,10 @@ void AvailabilityBoundaryVisitor::propagateAvailablity(Result &result) {
 }
 
 void AvailabilityBoundaryVisitor::visitAvailabilityBoundary(
-    Result const &result, llvm::function_ref<void(SILInstruction *)> visit) {
+    Result const &result,
+    llvm::function_ref<void(SILInstruction *,
+                            OSSALifetimeCompletion::LifetimeEnd end)>
+        visit) {
   for (auto *block : region) {
     auto available = result.getState(block) == State::Available;
     if (!available) {
@@ -323,14 +333,15 @@ void AvailabilityBoundaryVisitor::visitAvailabilityBoundary(
     }
     assert(hasUnavailableSuccessor() ||
            isa<UnreachableInst>(block->getTerminator()));
-    visit(block->getTerminator());
+    visit(block->getTerminator(),
+          OSSALifetimeCompletion::LifetimeEnd::Boundary);
   }
 }
 } // end anonymous namespace
 
 void OSSALifetimeCompletion::visitAvailabilityBoundary(
     SILValue value, AllowLeaks_t allowLeaks, const SSAPrunedLiveness &liveness,
-    llvm::function_ref<void(SILInstruction *)> visit) {
+    llvm::function_ref<void(SILInstruction *, LifetimeEnd end)> visit) {
 
   AvailabilityBoundaryVisitor visitor(value, allowLeaks);
 
@@ -348,9 +359,9 @@ static bool endLifetimeAtAvailabilityBoundary(
     const SSAPrunedLiveness &liveness) {
   bool changed = false;
   OSSALifetimeCompletion::visitAvailabilityBoundary(
-      value, allowLeaks, liveness, [&](auto *unreachable) {
+      value, allowLeaks, liveness, [&](auto *unreachable, auto end) {
         SILBuilderWithScope builder(unreachable);
-        endOSSALifetime(value, builder);
+        endOSSALifetime(value, end, builder);
         changed = true;
       });
   return changed;

lib/SILOptimizer/Utils/CanonicalizeOSSALifetime.cpp

@@ -275,8 +275,7 @@ void CanonicalizeOSSALifetime::extendLivenessToDeinitBarriers() {
 
   OSSALifetimeCompletion::visitAvailabilityBoundary(
       getCurrentDef(), OSSALifetimeCompletion::DoNotAllowLeaks,
-      completeLiveness, [&](auto *unreachable) {
-        recordUnreachableLifetimeEnd(unreachable);
+      completeLiveness, [&](auto *unreachable, auto end) {
         unreachable->visitPriorInstructions([&](auto *inst) {
           liveness->extendToNonUse(inst);
           return true;