Merge pull request swiftlang#42191 from eeckstein/small-optimizer-tweaks

Some small optimizer tweaks

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/Analysis/CalleeAnalysis.swift

@@ -16,13 +16,32 @@ import SIL
 public struct CalleeAnalysis {
   let bridged: BridgedCalleeAnalysis
 
-  public func getCallees(callee: Value) -> FunctionArray {
+  public func getCallees(callee: Value) -> FunctionArray? {
+    let bridgedFuncs = CalleeAnalysis_getCallees(bridged, callee.bridged)
+    if bridgedFuncs.incomplete != 0 {
+      return nil
+    }
+    return FunctionArray(bridged: bridgedFuncs)
+  }
+
+  public func getIncompleteCallees(callee: Value) -> FunctionArray {
     return FunctionArray(bridged: CalleeAnalysis_getCallees(bridged, callee.bridged))
   }
 
-  public func getDestructors(destroyInst: Instruction) -> FunctionArray {
-    return FunctionArray(bridged:
-      CalleeAnalysis_getInstCallees(bridged, destroyInst.bridged))
+  public func getDestructor(ofExactType type: Type) -> Function? {
+    let destructors = FunctionArray(bridged: CalleeAnalysis_getDestructors(bridged, type.bridged, /*isExactType*/ 1))
+    if destructors.count == 1 {
+      return destructors[0]
+    }
+    return nil
+  }
+
+  public func getDestructors(of type: Type) -> FunctionArray? {
+    let bridgedDtors = CalleeAnalysis_getDestructors(bridged, type.bridged, /*isExactType*/ 0)
+    if bridgedDtors.incomplete != 0 {
+      return nil
+    }
+    return FunctionArray(bridged: bridgedDtors)
   }
 }
 
@@ -35,6 +54,4 @@ public struct FunctionArray : RandomAccessCollection, FormattedLikeArray {
   public subscript(_ index: Int) -> Function {
     return BridgedFunctionArray_get(bridged, index).function
   }
-
-  public var allCalleesKnown: Bool { bridged.incomplete == 0 }
 }

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ReleaseDevirtualizer.swift

@@ -82,7 +82,7 @@ private func tryDevirtualizeReleaseOfObject(
 
   let type = allocRefInstruction.type
 
-  guard let dealloc = context.getDestructor(ofClass: type) else {
+  guard let dealloc = context.calleeAnalysis.getDestructor(ofExactType: type) else {
     return
   }
 

SwiftCompilerSources/Sources/Optimizer/InstructionPasses/SimplifyGlobalValue.swift

@@ -37,22 +37,20 @@ let simplifyGlobalValuePass = InstructionPass<GlobalValueInst>(
 private func checkUsers(of val: Value, users: inout Stack<Instruction>) -> Bool {
   for use in val.uses {
     let user = use.instruction
-    if user is RefCountingInst || user is DebugValueInst {
-      users.push(user)
-      continue
-    }
-    if let upCast = user as? UpcastInst {
-      if !checkUsers(of: upCast, users: &users) {
+    switch user {
+      case is RefCountingInst, is DebugValueInst, is FixLifetimeInst:
+        users.push(user)
+      case let upCast as UpcastInst:
+        if !checkUsers(of: upCast, users: &users) {
+          return false
+        }
+      case is RefElementAddrInst, is RefTailAddrInst:
+        // Projection instructions don't access the object header, so they don't
+        // prevent deleting reference counting instructions.
+        break
+      default:
         return false
-      }
-      continue
-    }
-    // Projection instructions don't access the object header, so they don't
-    // prevent deleting reference counting instructions.
-    if user is RefElementAddrInst || user is RefTailAddrInst {
-      continue
     }
-    return false
   }
   return true
 }

SwiftCompilerSources/Sources/Optimizer/PassManager/PassUtils.swift

@@ -112,10 +112,6 @@ struct PassContext {
     PassContext_fixStackNesting(_bridged, function.bridged)
   }
 
-  func getDestructor(ofClass type: Type) -> Function? {
-    PassContext_getDestructor(_bridged, type.bridged).function
-  }
-
   func getContextSubstitutionMap(for type: Type) -> SubstitutionMap {
     SubstitutionMap(PassContext_getContextSubstitutionMap(_bridged, type.bridged))
   }

include/swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h

@@ -147,7 +147,7 @@ class CalleeCache {
 
   /// Return the list of callees that can potentially be called at the
   /// given instruction. E.g. it could be destructors.
-  CalleeList getCalleeList(SILInstruction *I) const;
+  CalleeList getDestructors(SILType type, bool isExactType) const;
 
   CalleeList getCalleeList(SILDeclRef Decl) const;
 
@@ -224,9 +224,9 @@ class BasicCalleeAnalysis : public SILAnalysis {
     return Cache->getCalleeListOfValue(callee);
   }
 
-  CalleeList getCalleeList(SILInstruction *I) {
+  CalleeList getDestructors(SILType type, bool isExactType) {
     updateCache();
-    return Cache->getCalleeList(I);
+    return Cache->getDestructors(type, isExactType);
   }
 };
 

include/swift/SILOptimizer/OptimizerBridging.h

@@ -96,8 +96,9 @@ BridgedCalleeAnalysis PassContext_getCalleeAnalysis(BridgedPassContext context);
 
 BridgedCalleeList CalleeAnalysis_getCallees(BridgedCalleeAnalysis calleeAnalysis,
                                             BridgedValue callee);
-BridgedCalleeList CalleeAnalysis_getInstCallees(BridgedCalleeAnalysis calleeAnalysis,
-                                                BridgedInstruction inst);
+BridgedCalleeList CalleeAnalysis_getDestructors(BridgedCalleeAnalysis calleeAnalysis,
+                                                BridgedType type,
+                                                SwiftInt isExactType);
 SwiftInt BridgedFunctionArray_size(BridgedCalleeList callees);
 BridgedFunction BridgedFunctionArray_get(BridgedCalleeList callees,
                                          SwiftInt index);
@@ -140,9 +141,6 @@ BridgedFunction BasicBlockSet_getFunction(BridgedBasicBlockSet set);
 
 void AllocRefInstBase_setIsStackAllocatable(BridgedInstruction arb);
 
-OptionalBridgedFunction PassContext_getDestructor(BridgedPassContext context,
-                                                  BridgedType type);
-
 BridgedSubstitutionMap
 PassContext_getContextSubstitutionMap(BridgedPassContext context,
                                       BridgedType bridgedType);

lib/SILOptimizer/Analysis/BasicCalleeAnalysis.cpp

@@ -287,19 +287,28 @@ CalleeList CalleeCache::getCalleeList(FullApplySite FAS) const {
   return getCalleeListForCalleeKind(FAS.getCalleeOrigin());
 }
 
-// Return the list of functions that can be called via the given instruction.
-CalleeList CalleeCache::getCalleeList(SILInstruction *I) const {
-  // We support only deallocation instructions at the moment.
-  assert((isa<StrongReleaseInst>(I) || isa<ReleaseValueInst>(I)) &&
-         "A deallocation instruction expected");
-  auto Ty = I->getOperand(0)->getType();
-  while (auto payloadTy = Ty.getOptionalObjectType())
-    Ty = payloadTy;
-  auto Class = Ty.getClassOrBoundGenericClass();
-  if (!Class || Class->hasClangNode())
+/// Return the list of destructors of the class type \p type.
+///
+/// If \p type is an optional, look through that optional.
+/// If \p exactType is true, then \p type is treated like a final class type.
+CalleeList CalleeCache::getDestructors(SILType type, bool isExactType) const {
+  while (auto payloadTy = type.getOptionalObjectType()) {
+    type = payloadTy;
+  }
+  ClassDecl *classDecl = type.getClassOrBoundGenericClass();
+  if (!classDecl || classDecl->hasClangNode())
+    return CalleeList();
+
+  if (isExactType || classDecl->isFinal()) {
+    // In case of a final class, just pick the deinit of the class.
+    SILDeclRef destructor = SILDeclRef(classDecl->getDestructor());
+    if (SILFunction *destrImpl = M.lookUpFunction(destructor))
+      return CalleeList(destrImpl);
     return CalleeList();
-  SILDeclRef Destructor = SILDeclRef(Class->getDestructor());
-  return getCalleeList(Destructor);
+  }
+  // If all that doesn't help get the list of deinits as we do for regular class
+  // methods.
+  return getCalleeList(SILDeclRef(classDecl->getDestructor()));
 }
 
 void BasicCalleeAnalysis::dump() const {
@@ -332,10 +341,11 @@ BridgedCalleeList CalleeAnalysis_getCallees(BridgedCalleeAnalysis calleeAnalysis
   return {cl.getOpaquePtr(), cl.getOpaqueKind(), cl.isIncomplete()};
 }
 
-BridgedCalleeList CalleeAnalysis_getInstCallees(BridgedCalleeAnalysis calleeAnalysis,
-                                                BridgedInstruction inst) {
+BridgedCalleeList CalleeAnalysis_getDestructors(BridgedCalleeAnalysis calleeAnalysis,
+                                                BridgedType type,
+                                                SwiftInt isExactType) {
   BasicCalleeAnalysis *bca = static_cast<BasicCalleeAnalysis *>(calleeAnalysis.bca);
-  CalleeList cl = bca->getCalleeList(castToInst(inst));
+  CalleeList cl = bca->getDestructors(castToSILType(type), isExactType != 0);
   return {cl.getOpaquePtr(), cl.getOpaqueKind(), cl.isIncomplete()};
 }
 

lib/SILOptimizer/Analysis/FunctionOrder.cpp

@@ -40,10 +40,13 @@ void BottomUpFunctionOrder::DFS(SILFunction *Start) {
   for (auto &B : *Start) {
     for (auto &I : B) {
       auto FAS = FullApplySite::isa(&I);
-      if (!FAS && !isa<StrongReleaseInst>(&I) && !isa<ReleaseValueInst>(&I))
+      if (!FAS && !isa<StrongReleaseInst>(&I) && !isa<ReleaseValueInst>(&I) &&
+                  !isa<DestroyValueInst>(&I))
         continue;
 
-      auto Callees = FAS ? BCA->getCalleeList(FAS) : BCA->getCalleeList(&I);
+      auto Callees = FAS ? BCA->getCalleeList(FAS)
+                         : BCA->getDestructors(I.getOperand(0)->getType(),
+                                               /*isExactType*/ false);
       for (auto *CalleeFn : Callees) {
         // If not yet visited, visit the callee.
         if (DFSNum.find(CalleeFn) == DFSNum.end()) {

lib/SILOptimizer/PassManager/PassManager.cpp

@@ -1391,19 +1391,6 @@ void AllocRefInstBase_setIsStackAllocatable(BridgedInstruction arb) {
   castToInst<AllocRefInstBase>(arb)->setStackAllocatable();
 }
 
-OptionalBridgedFunction PassContext_getDestructor(BridgedPassContext context,
-                                                  BridgedType type) {
-  auto *cd = castToSILType(type).getClassOrBoundGenericClass();
-  assert(cd && "no class type allocated with alloc_ref");
-
-  auto *pm = castToPassInvocation(context)->getPassManager();
-  // Find the destructor of the type.
-  auto *destructor = cd->getDestructor();
-  SILDeclRef deallocRef(destructor, SILDeclRef::Kind::Deallocator);
-
-  return {pm->getModule()->lookUpFunction(deallocRef)};
-}
-
 BridgedSubstitutionMap
 PassContext_getContextSubstitutionMap(BridgedPassContext context,
                                       BridgedType bridgedType) {

test/SILOptimizer/sil_combine_cow.sil renamed to test/SILOptimizer/sil_combine_inst_passes.sil

@@ -104,3 +104,26 @@ bb0:
   return %t : $(Builtin.Int1, Builtin.BridgeObject)
 }
 
+sil_global private @outlined_global : $_ContiguousArrayStorage<Int>
+
+// CHECK-LABEL: sil @remove_arc_of_global_value
+// CHECK-NOT:   retain
+// CHECK-NOT:   release
+// CHECK-NOT:   fix_lifetime
+// CHECK-NOT:   debug_value
+// CHECK:     } // end sil function 'remove_arc_of_global_value'
+sil @remove_arc_of_global_value : $@convention(thin) () -> Int {
+bb0:
+  %0 = global_value @outlined_global : $_ContiguousArrayStorage<Int>
+  strong_retain %0 : $_ContiguousArrayStorage<Int>
+  debug_value %0 : $_ContiguousArrayStorage<Int>, let, name "x"
+  %2 = upcast %0 : $_ContiguousArrayStorage<Int> to $__ContiguousArrayStorageBase
+  strong_retain %2 : $__ContiguousArrayStorageBase
+  %13 = ref_tail_addr [immutable] %2 : $__ContiguousArrayStorageBase, $Int
+  %16 = load %13 : $*Int
+  fix_lifetime %0 : $_ContiguousArrayStorage<Int>
+  strong_release %2 : $__ContiguousArrayStorageBase
+  strong_release %0 : $_ContiguousArrayStorage<Int>
+  return %16 : $Int
+}
+