Sema: Always mark initializers of lazy vars as subsumed.

Previously, the initializer expressions of lazy vars would only be marked as
subsumed when the getter body for the var was synthesized. This didn't work
with `-experimental-lazy-typechecking` since accessor synthesis was not
guaranteed to happen. Consequently, SILGen would emit the initializer even
though it was already subsumed and then assert/crash since the init had also
not been checked and contextualized. Now lazy var inits are marked subsumed in
the request creating storage.

Resolves rdar://118421753

Author: tshortli

lib/AST/Decl.cpp

@@ -9188,13 +9188,6 @@ bool IsFunctionBodySkippedRequest::evaluate(
     // typecheck them.
     if (accessor->hasForcedStaticDispatch())
       return false;
-
-    if (auto *varDecl = dyn_cast<VarDecl>(accessor->getStorage())) {
-      // FIXME: If we don't typecheck the synthesized accessors of lazy storage
-      // properties then SILGen crashes when emitting the initializer.
-      if (varDecl->getAttrs().hasAttribute<LazyAttr>() && accessor->isSynthesized())
-        return false;
-    }
   }
 
   // Actor initializers need to be checked to determine delegation status.

lib/SILGen/SILGen.cpp

@@ -994,7 +994,7 @@ void SILGenModule::emitFunctionDefinition(SILDeclRef constant, SILFunction *f) {
       auto arg = param->getTypeCheckedDefaultExpr();
       auto loc = RegularLocation::getAutoGeneratedLocation(arg);
       preEmitFunction(constant, f, loc);
-      PrettyStackTraceSILFunction X("silgen emitDefaultArgGenerator ", f);
+      PrettyStackTraceSILFunction X("silgen default arg initializer", f);
       SILGenFunction SGF(*this, *f, initDC);
       SGF.emitGeneratorFunction(constant, arg);
       postEmitFunction(constant, f);
@@ -1005,7 +1005,7 @@ void SILGenModule::emitFunctionDefinition(SILDeclRef constant, SILFunction *f) {
       auto arg = param->getStoredProperty();
       auto loc = RegularLocation::getAutoGeneratedLocation(arg);
       preEmitFunction(constant, f, loc);
-      PrettyStackTraceSILFunction X("silgen emitDefaultArgGenerator ", f);
+      PrettyStackTraceSILFunction X("silgen stored property initializer", f);
       SILGenFunction SGF(*this, *f, initDC);
       SGF.emitGeneratorFunction(constant, arg);
       postEmitFunction(constant, f);

lib/Sema/TypeCheckStorage.cpp

@@ -1670,12 +1670,8 @@ synthesizeLazyGetterBody(AccessorDecl *Get, VarDecl *VD, VarDecl *Storage,
 
   Expr *InitValue;
   if (PBD->getInit(entryIndex)) {
-    PBD->setInitializerSubsumed(entryIndex);
-
-    if (!PBD->isInitializerChecked(entryIndex))
-      TypeChecker::typeCheckPatternBinding(PBD, entryIndex);
-
-    InitValue = PBD->getInit(entryIndex);
+    assert(PBD->isInitializerSubsumed(entryIndex));
+    InitValue = PBD->getCheckedAndContextualizedInit(entryIndex);
   } else {
     InitValue = new (Ctx) ErrorExpr(SourceRange(), Tmp2VD->getTypeInContext());
   }
@@ -2786,6 +2782,11 @@ LazyStoragePropertyRequest::evaluate(Evaluator &evaluator,
 
   addMemberToContextIfNeeded(PBD, VD->getDeclContext(), Storage);
 
+  // Make sure the original init is marked as subsumed.
+  auto *originalPBD = VD->getParentPatternBinding();
+  auto originalIndex = originalPBD->getPatternEntryIndexForVarDecl(VD);
+  originalPBD->setInitializerSubsumed(originalIndex);
+
   return Storage;
 }
 

test/Frontend/skip-function-bodies.swift

@@ -26,8 +26,7 @@
 // RUN: %target-swift-emit-module-interface(%t/NoSkip.swiftinterface) %s  -module-name Skip
 // RUN: %FileCheck %s --check-prefixes CHECK,CHECK-TEXTUAL --input-file %t/NoSkip.swiftinterface
 // RUN: diff -u %t/Skip.noninlinable.swiftinterface %t/NoSkip.swiftinterface
-// FIXME: Skipping all function bodies causes the interfaces not to match.
-// diff -u %t/Skip.all.swiftinterface %t/NoSkip.swiftinterface
+// RUN: diff -u %t/Skip.all.swiftinterface %t/NoSkip.swiftinterface
 
 // Skipping all function bodies should skip *all* SIL.
 // CHECK-SIL-SKIP-ALL: sil_stage canonical
@@ -480,6 +479,16 @@ public struct Struct {
   // CHECK-SIL-SKIP-NONINLINE: "Struct.varWithInlinableSetter.setter"
   // CHECK-SIL-SKIP-WITHOUTTYPES: "Struct.varWithInlinableSetter.setter"
 
+  public lazy var varWithLazyInitializer: Int = {
+    // We currently don't have a way to skip typechecking a pattern binding
+    // initializer expression
+    _blackHole("Struct.varWithLazyInitializer.init")
+    return 0
+  }()
+  // CHECK-TEXTUAL-NOT: "Struct.varWithLazyInitializer.init"
+  // CHECK-SIL-NO-SKIP: "Struct.varWithLazyInitializer.init"
+  // CHECK-SIL-SKIP-NONINLINE-OR-WITHOUTTYPES-NOT: "Struct.varWithLazyInitializer.init"
+
   public var varWithObserverDidSet: Int = 1 {
     didSet {
       // Body typechecked regardless

test/Inputs/lazy_typecheck.swift

@@ -133,6 +133,8 @@ protocol InternalProtoConformingToPublicProto: PublicProto {
 public struct PublicStruct {
   public var publicProperty: Int = NoTypecheck.int
   public var publicPropertyInferredType = ""
+  public var publicLazyProperty: Int = NoTypecheck.int
+  public var publicLazyPropertyInferred = 1
   @PublicWrapper public var publicWrappedProperty = 3.14
   @_transparent public var publicTransparentProperty: Int {
     get { return 1 }
@@ -192,6 +194,8 @@ struct InternalStruct: NoTypecheckProto {
 public class PublicClass {
   public var publicProperty: Int = NoTypecheck.int
   public var publicPropertyInferredType = ""
+  public var publicLazyProperty: Int = NoTypecheck.int
+  public var publicLazyPropertyInferred = 1
   @PublicWrapper public final var publicFinalWrappedProperty: Bool = false
   public static let publicStaticProperty: Int = NoTypecheck.int
   public static let publicStaticPropertyInferred = 2

test/Inputs/lazy_typecheck_client.swift

@@ -37,6 +37,8 @@ func testPublicStructs() {
   let _: Int = s.publicMethod()
   let _: Int = s.publicProperty
   let _: String = s.publicPropertyInferredType
+  let _: Int = s.publicLazyProperty
+  let _: Int = s.publicLazyPropertyInferred
   let _: Double = s.publicWrappedProperty
   let _: Double = s.$publicWrappedProperty.wrappedValue
   let _: Int = s.publicTransparentProperty
@@ -59,6 +61,8 @@ func testPublicClasses() {
   let _: Int = c.publicMethod()
   let _: Int = c.publicProperty
   let _: String = c.publicPropertyInferredType
+  let _: Int = c.publicLazyProperty
+  let _: Int = c.publicLazyPropertyInferred
   c.publicFinalWrappedProperty = true
   PublicClass.publicClassMethod()
   let _: Int = PublicClass.publicStaticProperty

test/SILGen/lazy_typecheck_var_init.swift

@@ -22,9 +22,7 @@ public struct S {
   // CHECK-LABEL: sil [transparent]{{.*}} @$s4Test1SV12instanceVar2Sivpfi : $@convention(thin) () -> Int {
   public var instanceVar2 = internalFunc(.b)
 
-  // FIXME: This initializer should be subsumed.
-  // CHECK-LAZY: sil [transparent] [ossa] @$s4Test1SV15lazyInstanceVarSivpfi : $@convention(thin) () -> Int {
-  // CHECK-NON-LAZY-NOT: sil [transparent] [ossa] @$s4Test1SV15lazyInstanceVarSivpfi : $@convention(thin) () -> Int {
+  // CHECK-NOT: s4Test1SV15lazyInstanceVarSivpfi
   // CHECK-LABEL: sil [transparent]{{.*}} @$s4Test1SV018$__lazy_storage_$_B11InstanceVar33_0E4F053AA3AB7D4CDE3A37DBA8EF0430LLSiSgvpfi : $@convention(thin) () -> Optional<Int> {
   public lazy var lazyInstanceVar = internalFunc()
 

test/SILGen/skip_function_bodies_storage.swift

@@ -17,14 +17,14 @@ public struct S {
 
   public lazy var lazyVar: Int = generateNumber()
 
+  // CHECK: sil [transparent] [serialized]{{.*}} @$s4main1SV7lazyVarSivM : $@yield_once @convention(method) (@inout S) -> @yields @inout Int
+  // CHECK: end sil function '$s4main1SV7lazyVarSivM'
+
   // CHECK: sil [lazy_getter]{{.*}} @$s4main1SV7lazyVarSivg : $@convention(method) (@inout S) -> Int
-  // CHECK: end sil function '$s4main1SV7lazyVarSivg'
+  // CHECK-NOT: end sil function '$s4main1SV7lazyVarSivg'
 
   // CHECK: sil{{.*}} @$s4main1SV7lazyVarSivs : $@convention(method) (Int, @inout S) -> ()
-  // CHECK: end sil function '$s4main1SV7lazyVarSivs'
-
-  // CHECK: sil [transparent] [serialized]{{.*}} @$s4main1SV7lazyVarSivM : $@yield_once @convention(method) (@inout S) -> @yields @inout Int
-  // CHECK: end sil function '$s4main1SV7lazyVarSivM'
+  // CHECK-NOT: end sil function '$s4main1SV7lazyVarSivs'
 
   // CHECK: sil [transparent]{{.*}} @$s4main1SV018$__lazy_storage_$_B3Var33_39316373847D37F82BD23977A13DEF23LLSiSgvpfi : $@convention(thin) () -> Optional<Int>
   // CHECK: end sil function '$s4main1SV018$__lazy_storage_$_B3Var33_39316373847D37F82BD23977A13DEF23LLSiSgvpfi'