AST: Allow @inline(__always)/@inline(never) to be applied to properties and subscripts

Previously we only permitted it on the accessor itself, but there is
no reason not to allow it on the storage declaration.

Fixes <https://bugs.swift.org/browse/SR-3624> / <rdar://problem/31865137>.

Author: slavapestov

include/swift/AST/Attr.def

@@ -179,7 +179,7 @@ SIMPLE_DECL_ATTR(unsafe_no_objc_tagged_pointer, UnsafeNoObjCTaggedPointer,
   UserInaccessible,
   19)
 DECL_ATTR(inline, Inline,
-  OnFunc | OnAccessor | OnConstructor,
+  OnVar | OnSubscript | OnAbstractFunction,
   20)
 DECL_ATTR(_semantics, Semantics,
   OnAbstractFunction | OnSubscript |

lib/SIL/SILDeclRef.cpp

@@ -528,26 +528,47 @@ IsSerialized_t SILDeclRef::isSerialized() const {
   return IsNotSerialized;
 }
 
-/// \brief True if the function has noinline attribute.
+/// \brief True if the function has an @inline(never) attribute.
 bool SILDeclRef::isNoinline() const {
   if (!hasDecl())
     return false;
-  if (auto InlineA = getDecl()->getAttrs().getAttribute<InlineAttr>())
-    if (InlineA->getKind() == InlineKind::Never)
+
+  auto *decl = getDecl();
+  if (auto *attr = decl->getAttrs().getAttribute<InlineAttr>())
+    if (attr->getKind() == InlineKind::Never)
       return true;
-  if (auto *semanticsA = getDecl()->getAttrs().getAttribute<SemanticsAttr>())
-    if (semanticsA->Value.equals("keypath.entry"))
+
+  if (auto *accessorDecl = dyn_cast<AccessorDecl>(decl)) {
+    auto *storage = accessorDecl->getStorage();
+    if (auto *attr = storage->getAttrs().getAttribute<InlineAttr>())
+      if (attr->getKind() == InlineKind::Never)
+        return true;
+  }
+
+  if (auto *attr = decl->getAttrs().getAttribute<SemanticsAttr>())
+    if (attr->Value.equals("keypath.entry"))
       return true;
+
   return false;
 }
 
-/// \brief True if the function has noinline attribute.
+/// \brief True if the function has the @inline(__always) attribute.
 bool SILDeclRef::isAlwaysInline() const {
   if (!hasDecl())
     return false;
-  if (auto InlineA = getDecl()->getAttrs().getAttribute<InlineAttr>())
-    if (InlineA->getKind() == InlineKind::Always)
+
+  auto *decl = getDecl();
+  if (auto attr = decl->getAttrs().getAttribute<InlineAttr>())
+    if (attr->getKind() == InlineKind::Always)
       return true;
+
+  if (auto *accessorDecl = dyn_cast<AccessorDecl>(decl)) {
+    auto *storage = accessorDecl->getStorage();
+    if (auto *attr = storage->getAttrs().getAttribute<InlineAttr>())
+      if (attr->getKind() == InlineKind::Always)
+        return true;
+  }
+
   return false;
 }
 

test/SILGen/functions.swift

@@ -1,4 +1,3 @@
-
 // RUN: %target-swift-emit-silgen -module-name functions -Xllvm -sil-full-demangle -parse-stdlib -parse-as-library -enable-sil-ownership %s | %FileCheck %s
 
 import Swift // just for Optional
@@ -422,27 +421,6 @@ func applyTransparent(_ x: Bool) -> Bool {
 @inline(never)
 func noinline_callee() {}
 
-// CHECK-LABEL: sil hidden [always_inline] @$s9functions20always_inline_calleeyyF : $@convention(thin) () -> ()
-@inline(__always)
-func always_inline_callee() {}
-
-// CHECK-LABEL: sil [always_inline] @$s9functions27public_always_inline_calleeyyF : $@convention(thin) () -> ()
-@inline(__always)
-public func public_always_inline_callee() {}
-
-protocol AlwaysInline {
-  func alwaysInlined()
-}
-
-// CHECK-LABEL: sil hidden [always_inline] @$s9functions19AlwaysInlinedMemberV06alwaysC0{{[_0-9a-zA-Z]*}}F : $@convention(method) (AlwaysInlinedMember) -> () {
-
-// protocol witness for functions.AlwaysInline.alwaysInlined <A : functions.AlwaysInline>(functions.AlwaysInline.Self)() -> () in conformance functions.AlwaysInlinedMember : functions.AlwaysInline in functions
-// CHECK-LABEL: sil private [transparent] [thunk] [always_inline] @$s9functions19AlwaysInlinedMemberVAA0B6InlineA2aDP06alwaysC0{{[_0-9a-zA-Z]*}}FTW : $@convention(witness_method: AlwaysInline) (@in_guaranteed AlwaysInlinedMember) -> () {
-struct AlwaysInlinedMember : AlwaysInline {
-  @inline(__always)
-  func alwaysInlined() {}
-}
-
 // CHECK-LABEL: sil hidden [Onone] @$s9functions10onone_funcyyF : $@convention(thin) () -> ()
 @_optimize(none)
 func onone_func() {}

test/SILGen/inlinable_attribute.swift

@@ -129,3 +129,21 @@ private class PrivateDerivedFromPublic : PublicBase {}
 
 // CHECK-LABEL: sil private @$s19inlinable_attribute21PrivateDerivedFromUFI{{.+}}LLC5horseAdA5HorseC_tcfc : $@convention(method) (@owned Horse, @owned PrivateDerivedFromUFI) -> @owned PrivateDerivedFromUFI
 private class PrivateDerivedFromUFI : UFIBase {}
+
+// Make sure that nested functions are also serializable.
+
+// CHECK-LABEL: sil [serialized] @$s19inlinable_attribute3basyyF
+@inlinable
+public func bas() {
+  // CHECK-LABEL: sil shared [serialized] @$s19inlinable_attribute3basyyF3zimL_yyF
+  func zim() {
+    // CHECK-LABEL: sil shared [serialized] @$s19inlinable_attribute3basyyF3zimL_yyF4zangL_yyF
+    func zang() { }
+  }
+
+  // CHECK-LABEL: sil shared [serialized] @$s19inlinable_attribute3bas{{[_0-9a-zA-Z]*}}U_
+  let zung = {
+    // CHECK-LABEL: sil shared [serialized] @$s19inlinable_attribute3basyyFyycfU_7zippityL_yyF
+    func zippity() { }
+  }
+}

test/SILGen/nested-function-fragility.swift

@@ -214,12 +214,12 @@ func func_type_attribute_with_space(x: @convention (c) () -> Int) {} // OK. Know
 var thinFunc : @thin () -> () // expected-error {{attribute is not supported}}
 
 @inline(never) func nolineFunc() {}
-@inline(never) var noinlineVar : Int // expected-error {{'@inline(never)' attribute cannot be applied to this declaration}} {{1-16=}}
+@inline(never) var noinlineVar : Int { return 0 }
 @inline(never) class FooClass { // expected-error {{'@inline(never)' attribute cannot be applied to this declaration}} {{1-16=}}
 }
 
 @inline(__always) func AlwaysInlineFunc() {}
-@inline(__always) var alwaysInlineVar : Int // expected-error {{'@inline(__always)' attribute cannot be applied to this declaration}} {{1-19=}}
+@inline(__always) var alwaysInlineVar : Int { return 0 }
 @inline(__always) class FooClass2 { // expected-error {{'@inline(__always)' attribute cannot be applied to this declaration}} {{1-19=}}
 }