DefinitInitialization: convert begin_access instructions of initializations to a static accesses

In case of `var` initializations, SILGen creates a dynamic begin/end_access pair around the initialization store.
If it's an initialization (and not a re-assign) it's guanranteed that it's an exlusive access and we can convert the access to an `[init] [static]` access.

#66496

Author: eeckstein

lib/SILOptimizer/Mandatory/DefiniteInitialization.cpp

@@ -2312,6 +2312,19 @@ void LifetimeChecker::handleSelfInitUse(unsigned UseID) {
   }
 }
 
+// In case of `var` initializations, SILGen creates a dynamic begin/end_access
+// pair around the initialization store. If it's an initialization (and not
+// a re-assign) it's guaranteed that it's an exclusive access and we can
+// convert the access to an `[init] [static]` access.
+static void setStaticInitAccess(SILValue memoryAddress) {
+  if (auto *ba = dyn_cast<BeginAccessInst>(memoryAddress)) {
+    if (ba->getEnforcement() == SILAccessEnforcement::Dynamic) {
+      ba->setEnforcement(SILAccessEnforcement::Static);
+      if (ba->getAccessKind() == SILAccessKind::Modify)
+        ba->setAccessKind(SILAccessKind::Init);
+    }
+  }
+}
 
 /// updateInstructionForInitState - When an instruction being analyzed moves
 /// from being InitOrAssign to some concrete state, update it for that state.
@@ -2336,6 +2349,8 @@ void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
     assert(!CA->isInitializationOfDest() &&
            "should not modify copy_addr that already knows it is initialized");
     CA->setIsInitializationOfDest(InitKind);
+    if (InitKind == IsInitialization)
+      setStaticInitAccess(CA->getDest());
     return;
   }
 
@@ -2382,6 +2397,7 @@ void LifetimeChecker::updateInstructionForInitState(unsigned UseID) {
               MarkMustCheckInst::CheckKind::InitableButNotConsumable);
         }
       }
+      setStaticInitAccess(AI->getDest());
     }
 
     return;

test/Concurrency/default_actor_definit.swift

@@ -40,7 +40,7 @@ actor C {
 // CHECK-LABEL: sil hidden @$s21default_actor_definit1CC1yACSgSi_tcfc
 // CHECK:         builtin "initializeDefaultActor"(%1 : $C)
 // CHECK:         [[X:%.*]] = ref_element_addr %1 : $C, #C.x
-// CHECK-NEXT:    [[ACCESS:%.*]] = begin_access [modify] [dynamic] [[X]] : $*String
+// CHECK-NEXT:    [[ACCESS:%.*]] = begin_access [init] [static] [[X]] : $*String
 // CHECK-NEXT:    store {{.*}} to [[ACCESS]] : $*String
 // CHECK-NEXT:    end_access [[ACCESS]] : $*String
 // CHECK:         cond_br {{%.*}}, bb1, bb2

test/SILOptimizer/default-cmo.swift

@@ -80,9 +80,8 @@ public func getSubmoduleKlassMember() -> Int {
 }
 
 // CHECK-LABEL: sil @$s4Main26getSubmoduleKlassMemberTBDSiyF
-// CHECK:         [[F:%[0-9]+]] = function_ref @$s9ModuleTBD20submoduleKlassMemberSiyF
-// CHECK:         [[I:%[0-9]+]] = apply [[F]]
-// CHECK:         return [[I]]
+// CHECK-NOT:     function_ref 
+// CHECK-NOT:     apply 
 // CHECK:       } // end sil function '$s4Main26getSubmoduleKlassMemberTBDSiyF'
 public func getSubmoduleKlassMemberTBD() -> Int {
   return ModuleTBD.submoduleKlassMember()

test/SILOptimizer/definite_init_actor.swift

@@ -83,7 +83,7 @@ actor BoringActor {
     // CHECK-LABEL: sil hidden @$s4test14SingleVarActorC10iterationsACSi_tYacfc : $@convention(method) @async (Int, @owned SingleVarActor) -> @owned SingleVarActor {
     // CHECK:   bb0({{%[0-9]+}} : $Int, [[SELF:%[0-9]+]] : $SingleVarActor):
     // CHECK:       [[MYVAR_REF:%[0-9]+]] = ref_element_addr [[SELF]] : $SingleVarActor, #SingleVarActor.myVar
-    // CHECK:       [[MYVAR:%[0-9]+]] = begin_access [modify] [dynamic] [[MYVAR_REF]] : $*Int
+    // CHECK:       [[MYVAR:%[0-9]+]] = begin_access [init] [static] [[MYVAR_REF]] : $*Int
     // CHECK:       store {{%[0-9]+}} to [[MYVAR]] : $*Int
     // CHECK-NEXT:  end_access [[MYVAR]]
     // CHECK-NEXT:  hop_to_executor [[SELF]] : $SingleVarActor
@@ -196,7 +196,7 @@ actor MultiVarActor {
     // CHECK-LABEL: sil hidden @$s4test13MultiVarActorC10doNotThrowACSb_tYaKcfc : $@convention(method) @async (Bool, @owned MultiVarActor) -> (@owned MultiVarActor, @error any Error) {
     // CHECK:   bb0({{%[0-9]+}} : $Bool, [[SELF:%[0-9]+]] : $MultiVarActor):
     // CHECK:       [[REF:%[0-9]+]] = ref_element_addr [[SELF]] : $MultiVarActor, #MultiVarActor.firstVar
-    // CHECK:       [[VAR:%[0-9]+]] = begin_access [modify] [dynamic] [[REF]] : $*Int
+    // CHECK:       [[VAR:%[0-9]+]] = begin_access [init] [static] [[REF]] : $*Int
     // CHECK:       store {{%[0-9]+}} to [[VAR]] : $*Int
     // CHECK-NEXT:  end_access [[VAR]]
     // CHECK-NEXT:  hop_to_executor %1 : $MultiVarActor

test/SILOptimizer/definite_init_failable_initializers.swift

@@ -735,7 +735,7 @@ class FailableBaseClass {
 // CHECK:       bb0(%0 : $FailableBaseClass):
 // CHECK:         [[CANARY:%.*]] = apply
 // CHECK-NEXT:    [[MEMBER_ADDR:%.*]] = ref_element_addr %0
-// CHECK-NEXT:    [[WRITE:%.*]] = begin_access [modify] [dynamic] [[MEMBER_ADDR]] : $*Canary
+// CHECK-NEXT:    [[WRITE:%.*]] = begin_access [init] [static] [[MEMBER_ADDR]] : $*Canary
 // CHECK-NEXT:    store [[CANARY]] to [[WRITE]]
 // CHECK-NEXT:    end_access [[WRITE]] : $*Canary
 // CHECK-NEXT:    strong_release %0
@@ -849,7 +849,7 @@ class FailableDerivedClass : FailableBaseClass {
 // CHECK:         [[CANARY_FUN:%.*]] = function_ref @$s35definite_init_failable_initializers6CanaryCACycfC :
 // CHECK:         [[CANARY:%.*]] = apply [[CANARY_FUN]](
 // CHECK-NEXT:    [[MEMBER_ADDR:%.*]] = ref_element_addr [[SELF]]
-// CHECK-NEXT:    [[WRITE:%.*]] = begin_access [modify] [dynamic] [[MEMBER_ADDR]] : $*Canary
+// CHECK-NEXT:    [[WRITE:%.*]] = begin_access [init] [static] [[MEMBER_ADDR]] : $*Canary
 // CHECK-NEXT:    store [[CANARY]] to [[WRITE]]
 // CHECK-NEXT:    end_access [[WRITE]] : $*Canary
 // CHECK-NEXT:    strong_release [[SELF]]

test/SILOptimizer/definite_init_markuninitialized_rootself.sil

@@ -21,6 +21,17 @@ class RootClassWithNontrivialStoredProperties {
 }
 
 class SomeClass {}
+
+final class IntClass {
+  var i: Int
+  init(_ i: Int)
+}
+
+final class GenericClass<T> {
+  var t: T
+  init(_ t: T)
+}
+
 sil @getSomeClass : $@convention(thin) () -> @owned SomeClass
 sil @getSomeOptionalClass : $@convention(thin) () -> Optional<SomeClass>
 
@@ -131,3 +142,45 @@ bb0(%0 : @owned $RootClassWithNontrivialStoredProperties):
   %13 = tuple ()
   return %13 : $()
 }
+
+// CHECK-LABEL: sil [ossa] @init_IntClass :
+// CHECK:         [[ACCESS:%.*]] = begin_access [init] [static]
+// CHECK:         store %0 to [trivial] [[ACCESS]]
+// CHECK:         [[ACCESS2:%.*]] = begin_access [modify] [dynamic]
+// CHECK:         store %0 to [trivial] [[ACCESS2]]
+// CHECK:       } // end sil function 'init_IntClass'
+sil [ossa] @init_IntClass : $@convention(method) (Int, @owned IntClass) -> @owned IntClass {
+bb0(%0 : $Int, %1 : @owned $IntClass):
+  %4 = mark_uninitialized [rootself] %1 : $IntClass
+  %5 = begin_borrow %4 : $IntClass
+  %6 = ref_element_addr %5 : $IntClass, #IntClass.i
+  %7 = begin_access [modify] [dynamic] %6 : $*Int
+  assign %0 to %7 : $*Int
+  end_access %7 : $*Int
+  %10 = begin_access [modify] [dynamic] %6 : $*Int
+  assign %0 to %10 : $*Int
+  end_access %10 : $*Int
+  end_borrow %5 : $IntClass
+  return %4 : $IntClass
+}
+
+// CHECK-LABEL: sil [ossa] @init_GenericClass :
+// CHECK:         [[ACCESS:%.*]] = begin_access [init] [static]
+// CHECK:         copy_addr %0 to [init] [[ACCESS]]
+// CHECK:         [[ACCESS2:%.*]] = begin_access [modify] [dynamic]
+// CHECK:         copy_addr [take] %0 to [[ACCESS2]]
+// CHECK:       } // end sil function 'init_GenericClass'
+sil [ossa] @init_GenericClass : $@convention(method) <T> (@in T, @owned GenericClass<T>) -> @owned GenericClass<T> {
+bb0(%0 : $*T, %1 : @owned $GenericClass<T>):
+  %4 = mark_uninitialized [rootself] %1 : $GenericClass<T>
+  %5 = begin_borrow %4 : $GenericClass<T>
+  %8 = ref_element_addr %5 : $GenericClass<T>, #GenericClass.t
+  %9 = begin_access [modify] [dynamic] %8 : $*T
+  copy_addr %0 to %9 : $*T
+  end_access %9 : $*T
+  %12 = begin_access [modify] [dynamic] %8 : $*T
+  copy_addr [take] %0 to %12 : $*T
+  end_access %12 : $*T
+  end_borrow %5 : $GenericClass<T>
+  return %4 : $GenericClass<T>
+}

test/SILOptimizer/definite_init_root_class.swift

@@ -31,7 +31,7 @@ class FirstClass {
     // CHECK:   [[INIT:%.*]] = function_ref @$s24definite_init_root_class10OtherClassCACycfC : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[OTHER:%.*]] = apply [[INIT]]([[METATYPE]]) : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[X_ADDR:%.*]] = ref_element_addr %1 : $FirstClass, #FirstClass.x
-    // CHECK:   [[X_ACCESS:%.*]] = begin_access [modify] [dynamic] %15 : $*OtherClass
+    // CHECK:   [[X_ACCESS:%.*]] = begin_access [init] [static] %15 : $*OtherClass
     // CHECK:   [[ONE:%.*]] = integer_literal $Builtin.Int1, -1
     // CHECK:   store [[ONE]] to [[CONTROL]] : $*Builtin.Int1
     // CHECK:   store [[OTHER]] to [[X_ACCESS]] : $*OtherClass
@@ -115,7 +115,7 @@ class SecondClass {
     // CHECK:   [[INIT:%.*]] = function_ref @$s24definite_init_root_class10OtherClassCACycfC : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[OTHER:%.*]] = apply [[INIT]]([[METATYPE]]) : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[X_ADDR:%.*]] = ref_element_addr %1 : $SecondClass, #SecondClass.x
-    // CHECK:   [[X_ACCESS:%.*]] = begin_access [modify] [dynamic] [[X_ADDR]] : $*OtherClass
+    // CHECK:   [[X_ACCESS:%.*]] = begin_access [init] [static] [[X_ADDR]] : $*OtherClass
     // CHECK:   [[ONE:%.*]] = integer_literal $Builtin.Int2, 1
     // CHECK:   store [[ONE]] to [[CONTROL]] : $*Builtin.Int2
     // CHECK:   store [[OTHER]] to [[X_ACCESS]] : $*OtherClass
@@ -138,7 +138,7 @@ class SecondClass {
     // CHECK:   [[INIT:%.*]] = function_ref @$s24definite_init_root_class10OtherClassCACycfC : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[OTHER:%.*]] = apply [[INIT]]([[METATYPE]]) : $@convention(method) (@thick OtherClass.Type) -> @owned OtherClass
     // CHECK:   [[Y_ADDR:%.*]] = ref_element_addr %1 : $SecondClass, #SecondClass.y
-    // CHECK:   [[Y_ACCESS:%.*]] = begin_access [modify] [dynamic] [[Y_ADDR]] : $*OtherClass
+    // CHECK:   [[Y_ACCESS:%.*]] = begin_access [init] [static] [[Y_ADDR]] : $*OtherClass
     // CHECK:   [[THREE:%.*]] = integer_literal $Builtin.Int2, -1
     // CHECK:   store [[THREE]] to [[CONTROL]] : $*Builtin.Int2
     // CHECK:   store [[OTHER]] to [[Y_ACCESS]] : $*OtherClass

test/SILOptimizer/devirt_speculative_init.swift

@@ -20,17 +20,17 @@ public class BigCat : Cat {
   }
 }
 
-public func make(type: Cat.Type, cats: Int) {
-  type.init(cats: cats)
+public func make(type: Cat.Type, cats: Int) -> Cat {
+  return type.init(cats: cats)
 }
 
-// CHECK-LABEL: sil @$s23devirt_speculative_init4make4type4catsyAA3CatCm_SitF : $@convention(thin) (@thick Cat.Type, Int) -> ()
+// CHECK-LABEL: sil @$s23devirt_speculative_init4make4type4catsAA3CatCAFm_SitF : $@convention(thin) (@thick Cat.Type, Int) -> @owned Cat {
 // CHECK:   checked_cast_br [exact] %0 : $@thick Cat.Type to @thick Cat.Type, bb2, bb3
-// CHECK: bb1:
+// CHECK: bb1{{.*}}:
 // CHECK:   return
 // CHECK: bb2({{%.*}} : $@thick Cat.Type):
-// CHECK:   alloc_ref [stack] $Cat
+// CHECK:   alloc_ref $Cat
 // CHECK:   br bb1
 // CHECK: bb3:
-// CHECK:   alloc_ref [stack] $BigCat
+// CHECK:   alloc_ref $BigCat
 // CHECK:   br bb1

test/SILOptimizer/merge_exclusivity.swift

@@ -377,8 +377,7 @@ private struct EscapedTransform<T>: WriteProt {
 
 // TESTSIL-LABEL: sil [noinline] @$s17merge_exclusivity14run_MergeTest9yySiF : $@convention(thin)
 // TESTSIL: [[REFADDR:%.*]] = ref_element_addr {{.*}} : $StreamClass, #StreamClass.buffer
-// TESTSIL-NEXT: [[B1:%.*]] = begin_access [modify] [{{.*}}] [no_nested_conflict] [[REFADDR]]
-// TESTSIL: end_access [[B1]]
+// TESTSIL-NEXT: store {{.*}} to [[REFADDR]]
 // TESTSIL: [[BCONF:%.*]] = begin_access [modify] [{{.*}}] [[REFADDR]]
 // TESTSIL: end_access [[BCONF]]
 // TESTSIL: [[BCONF:%.*]] = begin_access [modify] [{{.*}}] [[REFADDR]]

test/sil-func-extractor/basic.swift

@@ -46,7 +46,7 @@
 // EXTRACT-INIT-LABEL:   sil @$s5basic7VehicleC1nACSi_tcfc : $@convention(method) (Int, @owned Vehicle) -> @owned Vehicle {
 // EXTRACT-INIT:         bb0
 // EXTRACT-INIT-NEXT:      ref_element_addr
-// EXTRACT-INIT-NEXT:      begin_access [modify] [dynamic]
+// EXTRACT-INIT-NEXT:      begin_access [init] [static]
 // EXTRACT-INIT-NEXT:      store
 // EXTRACT-INIT-NEXT:      end_access
 // EXTRACT-INIT-NEXT:      return