Merge pull request swiftlang#82067 from meg-gupta/lifetimeunderscored

Update spelling for representing lifetime dependencies to @_lifetime

Author: meg-gupta

include/swift/AST/ASTBridging.h

@@ -1165,10 +1165,11 @@ BridgedLifetimeEntry BridgedLifetimeEntry_createParsed(
     BridgedASTContext cContext, BridgedSourceRange cRange,
     BridgedArrayRef cSources, BridgedLifetimeDescriptor cTarget);
 
-SWIFT_NAME("BridgedLifetimeAttr.createParsed(_:atLoc:range:entry:)")
+SWIFT_NAME(
+    "BridgedLifetimeAttr.createParsed(_:atLoc:range:entry:isUnderscored:)")
 BridgedLifetimeAttr BridgedLifetimeAttr_createParsed(
     BridgedASTContext cContext, BridgedSourceLoc cAtLoc,
-    BridgedSourceRange cRange, BridgedLifetimeEntry cEntry);
+    BridgedSourceRange cRange, BridgedLifetimeEntry cEntry, bool isUnderscored);
 
 enum ENUM_EXTENSIBILITY_ATTR(closed) BridgedMacroSyntax {
   BridgedMacroSyntaxFreestanding,

include/swift/AST/Attr.h

@@ -239,6 +239,10 @@ class DeclAttribute : public AttributeBase {
 
       NumFeatures : 31
     );
+
+    SWIFT_INLINE_BITFIELD(LifetimeAttr, DeclAttribute, 1,
+      isUnderscored : 1
+    );
   } Bits;
   // clang-format on
 
@@ -3351,26 +3355,33 @@ class LifetimeAttr final : public DeclAttribute {
   LifetimeEntry *entry;
 
   LifetimeAttr(SourceLoc atLoc, SourceRange baseRange, bool implicit,
-               LifetimeEntry *entry)
+               LifetimeEntry *entry, bool isUnderscored)
       : DeclAttribute(DeclAttrKind::Lifetime, atLoc, baseRange, implicit),
-        entry(entry) {}
+        entry(entry) {
+    Bits.LifetimeAttr.isUnderscored = isUnderscored;
+  }
 
 public:
   static LifetimeAttr *create(ASTContext &context, SourceLoc atLoc,
                               SourceRange baseRange, bool implicit,
-                              LifetimeEntry *entry);
+                              LifetimeEntry *entry, bool isUnderscored);
 
   LifetimeEntry *getLifetimeEntry() const { return entry; }
 
+  bool isUnderscored() const { return bool(Bits.LifetimeAttr.isUnderscored); }
+
   static bool classof(const DeclAttribute *DA) {
     return DA->getKind() == DeclAttrKind::Lifetime;
   }
 
   /// Create a copy of this attribute.
   LifetimeAttr *clone(ASTContext &ctx) const {
-    return new (ctx) LifetimeAttr(AtLoc, Range, isImplicit(), entry);
+    return new (ctx)
+        LifetimeAttr(AtLoc, Range, isImplicit(), entry, isUnderscored());
   }
 
+  std::string getString() const;
+
   bool isEquivalent(const LifetimeAttr *other, Decl *attachedTo) const;
 };
 

include/swift/AST/DeclAttr.def

@@ -842,6 +842,7 @@ DECL_ATTR(lifetime, Lifetime,
   OnAccessor | OnConstructor | OnFunc | OnSubscript,
   LongAttribute | ABIBreakingToAdd | ABIStableToRemove | APIBreakingToAdd | APIStableToRemove | AllowMultipleAttributes | EquivalentInABIAttr,
   161)
+DECL_ATTR_ALIAS(_lifetime, Lifetime)
 
 SIMPLE_DECL_ATTR(_addressableSelf, AddressableSelf,
   OnAccessor | OnConstructor | OnFunc | OnSubscript,

include/swift/AST/DiagnosticsSema.def

@@ -8265,6 +8265,9 @@ ERROR(pack_iteration_where_clause_not_supported, none,
 // MARK: Lifetime Dependence Syntax
 //------------------------------------------------------------------------------
 
+WARNING(use_lifetime_underscored, PointsToFirstBadToken,
+      "Unsupported use of @lifetime, use @_lifetime to specify lifetime dependencies", ())
+
 ERROR(lifetime_dependence_invalid_param_name, none,
       "invalid parameter name specified %0", (Identifier))
 ERROR(lifetime_dependence_invalid_param_index, none,
@@ -8299,7 +8302,7 @@ ERROR(lifetime_dependence_immortal_alone, none,
       "cannot specify any other dependence source along with immortal", ())
 ERROR(lifetime_dependence_invalid_inherit_escapable_type, none,
       "cannot copy the lifetime of an Escapable type, use "
-      "'@lifetime(%1%0)' instead",
+      "'@_lifetime(%1%0)' instead",
       (StringRef, StringRef))
 ERROR(lifetime_dependence_cannot_use_parsed_borrow_consuming, none,
       "invalid use of %0 dependence with %1 ownership",
@@ -8330,11 +8333,11 @@ ERROR(lifetime_dependence_feature_required_inout, none,
       (StringRef, Identifier))
 
 ERROR(lifetime_dependence_cannot_infer_return, none,
-      "%0 with a ~Escapable result requires '@lifetime(...)'", (StringRef))
+      "%0 with a ~Escapable result requires '@_lifetime(...)'", (StringRef))
 ERROR(lifetime_dependence_cannot_infer_mutating, none,
-      "%0 with a ~Escapable 'self' requires '@lifetime(self: ...)'", (StringRef))
+      "%0 with a ~Escapable 'self' requires '@_lifetime(self: ...)'", (StringRef))
 ERROR(lifetime_dependence_cannot_infer_inout, none,
-      "%0 with a ~Escapable 'inout' parameter requires '@lifetime(%1: ...)'",
+      "%0 with a ~Escapable 'inout' parameter requires '@_lifetime(%1: ...)'",
       (StringRef, Identifier))
 
 //------------------------------------------------------------------------------
@@ -8345,15 +8348,15 @@ ERROR(lifetime_dependence_cannot_infer_return_no_param, none,
       "%0 with a ~Escapable result needs a parameter to depend on",
       (StringRef))
 NOTE(lifetime_dependence_cannot_infer_return_immortal, none,
-     "'@lifetime(immortal)' can be used to indicate that values produced by "
+     "'@_lifetime(immortal)' can be used to indicate that values produced by "
      "this initializer have no lifetime dependencies", ())
 ERROR(lifetime_dependence_cannot_infer_bitwisecopyable, none,
       "cannot infer lifetime dependence on %0 because '%1' is BitwiseCopyable, "
-      "specify '@lifetime(borrow self)'",
+      "specify '@_lifetime(borrow self)'",
       (StringRef, StringRef))
 ERROR(lifetime_dependence_cannot_infer_kind, none,
       "cannot infer the lifetime dependence scope on %0 with a ~Escapable "
-      "parameter, specify '@lifetime(borrow %1)' or '@lifetime(copy %1)'",
+      "parameter, specify '@_lifetime(borrow %1)' or '@_lifetime(copy %1)'",
       (StringRef, StringRef))
 ERROR(lifetime_dependence_cannot_infer_scope_ownership, none,
       "cannot borrow the lifetime of '%0', which has consuming ownership on %1",

include/swift/AST/Module.h

@@ -1158,6 +1158,9 @@ class ModuleDecl
   /// \returns true if this module is the "swift" standard library module.
   bool isStdlibModule() const;
 
+  /// \returns true if this module is the "Cxx" module.
+  bool isCxxModule() const;
+
   /// \returns true if this module is the "_Concurrency" standard library module.
   bool isConcurrencyModule() const;
 

include/swift/AST/PrintOptions.h

@@ -395,6 +395,9 @@ struct PrintOptions {
   /// as public
   bool SuppressIsolatedDeinit = false;
 
+  /// Suppress @_lifetime attribute and emit @lifetime instead.
+  bool SuppressLifetimes = false;
+
   /// Whether to print the \c{/*not inherited*/} comment on factory initializers.
   bool PrintFactoryInitializerComment = true;
 

include/swift/Basic/Features.def

@@ -525,6 +525,9 @@ EXPERIMENTAL_FEATURE(ModuleSelector, false)
 /// in a file scope.
 EXPERIMENTAL_FEATURE(DefaultIsolationPerFile, false)
 
+/// Enable @_lifetime attribute
+SUPPRESSIBLE_EXPERIMENTAL_FEATURE(Lifetimes, true)
+
 #undef EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE
 #undef EXPERIMENTAL_FEATURE
 #undef UPCOMING_FEATURE

include/swift/Parse/Parser.h

@@ -1127,8 +1127,8 @@ class Parser {
   );
 
   /// Parse the @lifetime attribute.
-  ParserResult<LifetimeAttr> parseLifetimeAttribute(SourceLoc AtLoc,
-                                                    SourceLoc Loc);
+  ParserResult<LifetimeAttr>
+  parseLifetimeAttribute(StringRef attrName, SourceLoc atLoc, SourceLoc loc);
 
   /// Common utility to parse swift @lifetime decl attribute and SIL @lifetime
   /// type modifier.
@@ -1158,7 +1158,8 @@ class Parser {
 
   bool isParameterSpecifier() {
     if (Tok.is(tok::kw_inout)) return true;
-    if (Context.LangOpts.hasFeature(Feature::LifetimeDependence) &&
+    if ((Context.LangOpts.hasFeature(Feature::LifetimeDependence) ||
+         Context.LangOpts.hasFeature(Feature::Lifetimes)) &&
         isSILLifetimeDependenceToken())
       return true;
     if (!canHaveParameterSpecifierContextualKeyword()) return false;

lib/AST/ASTPrinter.cpp

@@ -3261,6 +3261,13 @@ suppressingFeatureIsolatedDeinit(PrintOptions &options,
   action();
 }
 
+static void
+suppressingFeatureLifetimes(PrintOptions &options,
+                                     llvm::function_ref<void()> action) {
+  llvm::SaveAndRestore<bool> scope(options.SuppressLifetimes, true);
+  action();
+}
+
 namespace {
 struct ExcludeAttrRAII {
   std::vector<AnyAttrKind> &ExcludeAttrList;

lib/AST/Attr.cpp

@@ -1690,7 +1690,11 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
 
   case DeclAttrKind::Lifetime: {
     auto *attr = cast<LifetimeAttr>(this);
-    Printer << attr->getLifetimeEntry()->getString();
+    if (!attr->isUnderscored() || Options.SuppressLifetimes) {
+      Printer << "@lifetime" << attr->getLifetimeEntry()->getString();
+    } else {
+      Printer << "@_lifetime" << attr->getLifetimeEntry()->getString();
+    }
     break;
   }
 
@@ -1962,7 +1966,7 @@ StringRef DeclAttribute::getAttrName() const {
       return "_allowFeatureSuppression";
     }
   case DeclAttrKind::Lifetime:
-    return "lifetime";
+    return cast<LifetimeAttr>(this)->isUnderscored() ? "_lifetime" : "lifetime";
   }
   llvm_unreachable("bad DeclAttrKind");
 }
@@ -3224,8 +3228,15 @@ isEquivalent(const AllowFeatureSuppressionAttr *other, Decl *attachedTo) const {
 
 LifetimeAttr *LifetimeAttr::create(ASTContext &context, SourceLoc atLoc,
                                    SourceRange baseRange, bool implicit,
-                                   LifetimeEntry *entry) {
-  return new (context) LifetimeAttr(atLoc, baseRange, implicit, entry);
+                                   LifetimeEntry *entry, bool isUnderscored) {
+  return new (context)
+      LifetimeAttr(atLoc, baseRange, implicit, entry, isUnderscored);
+}
+
+std::string LifetimeAttr::getString() const {
+  return (isUnderscored() ? std::string("@_lifetime")
+                          : std::string("@lifetime")) +
+         getLifetimeEntry()->getString();
 }
 
 bool LifetimeAttr::isEquivalent(const LifetimeAttr *other,