@abi checking

include/swift/AST/AttrKind.h

@@ -145,6 +145,8 @@ enum class DeclAttrKind : unsigned {
 #include "swift/AST/DeclAttr.def"
 };
 
+StringRef getDeclAttrKindID(DeclAttrKind kind);
+
 enum : unsigned {
   NumDeclAttrKinds = static_cast<unsigned>(DeclAttrKind::Last_DeclAttr) + 1,
   NumDeclAttrKindBits = countBitsUsed(NumDeclAttrKinds - 1),

include/swift/AST/Decl.h

@@ -1041,6 +1041,10 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl>, public Swi
   /// from source code.
   void attachParsedAttrs(DeclAttributes attrs);
 
+  /// Retrieve the custom name in the \c @objc attribute, if present.
+  std::optional<ObjCSelector>
+  getExplicitObjCName(bool allowInvalid = false) const;
+
   /// True if this declaration provides an implementation for an imported
   /// Objective-C declaration. This implies various restrictions and special
   /// behaviors for it and, if it's an extension, its members.
@@ -5919,6 +5923,13 @@ class AbstractStorageDecl : public ValueDecl {
   /// Return the interface type of the stored value.
   Type getValueInterfaceType() const;
 
+  /// Retrieve the source range of the variable type, or an invalid range if the
+  /// variable's type is not explicitly written in the source.
+  ///
+  /// Only for use in diagnostics.  It is not always possible to always
+  /// precisely point to the variable type because of type aliases.
+  SourceRange getTypeSourceRangeForDiagnostics() const;
+
   /// Determine how this storage is implemented.
   StorageImplInfo getImplInfo() const;
 
@@ -6353,13 +6364,6 @@ class VarDecl : public AbstractStorageDecl {
   /// and not just getInterfaceType().
   Type getTypeInContext() const;
 
-  /// Retrieve the source range of the variable type, or an invalid range if the
-  /// variable's type is not explicitly written in the source.
-  ///
-  /// Only for use in diagnostics.  It is not always possible to always
-  /// precisely point to the variable type because of type aliases.
-  SourceRange getTypeSourceRangeForDiagnostics() const;
-
   /// Determine the mutability of this variable declaration when
   /// accessed from a given declaration context.
   StorageMutability mutability(

include/swift/AST/DiagnosticEngine.h

@@ -702,6 +702,10 @@ namespace swift {
     /// Flush the active diagnostic to the diagnostic output engine.
     void flush();
 
+    /// Returns the \c SourceManager associated with \c SourceLoc s for this
+    /// diagnostic.
+    SourceManager &getSourceManager();
+
     /// Prevent the diagnostic from behaving more severely than \p limit. For
     /// instance, if \c DiagnosticBehavior::Warning is passed, an error will be
     /// emitted as a warning, but a note will still be emitted as a note.
@@ -1561,6 +1565,10 @@ namespace swift {
     }
   };
 
+  inline SourceManager &InFlightDiagnostic::getSourceManager() {
+    return Engine->SourceMgr;
+  }
+
   /// Remember details about the state of a diagnostic engine and restore them
   /// when the object is destroyed.
   ///

include/swift/AST/DiagnosticsSema.def

@@ -8351,16 +8351,16 @@ ERROR(attr_abi_mismatched_kind,none,
 
 ERROR(attr_abi_mismatched_arity,none,
       "cannot give %kind0 the ABI of a %kindonly0 with a different number of "
-      "low-level parameters",
-      (ValueDecl *))
+      "%select{|generic }1parameters",
+      (Decl *, /*genericParams=*/bool))
 
 ERROR(attr_abi_mismatched_throws,none,
       "cannot give %0 the ABI of a %kindonly0 which %select{cannot|can}1 throw",
-      (ValueDecl *, /*abiCanThrow=*/bool))
+      (Decl *, /*abiCanThrow=*/bool))
 
 ERROR(attr_abi_mismatched_async,none,
       "cannot give %0 the ABI of %select{a non-async|an async}1 %kindonly0",
-      (ValueDecl *, /*abiIsAsync=*/bool))
+      (Decl *, /*abiIsAsync=*/bool))
 
 ERROR(attr_abi_mismatched_pbd_size,none,
       "cannot give pattern binding the ABI of a binding with "
@@ -8369,13 +8369,89 @@ ERROR(attr_abi_mismatched_pbd_size,none,
 
 ERROR(attr_abi_mismatched_var,none,
       "no match for %select{%kind0 in the ABI|ABI %kind0}1",
-      (ValueDecl *, /*isABI=*/bool))
+      (Decl *, /*isABI=*/bool))
 
 ERROR(attr_abi_incompatible_with_silgen_name,none,
       "cannot use '@_silgen_name' and '@abi' on the same %0 because they serve "
       "the same purpose",
       (DescriptiveDeclKind))
 
+ERROR(attr_abi_missing_attr,none,
+      "missing '%0' %select{attribute|modifier}1 in '@abi'",
+      (StringRef, bool))
+ERROR(attr_abi_extra_attr,none,
+      "extra %select{|implicit }2'%0' %select{attribute|modifier}1 in '@abi'",
+      (StringRef, bool, /*isImplicit=*/bool))
+ERROR(attr_abi_forbidden_attr,none,
+      "unused '%0' %select{attribute|modifier}1 in '@abi'",
+      (StringRef, bool))
+REMARK(abi_attr_inferred_attribute,none,
+       "inferred '%0' in '@abi' to match %select{attribute|modifier}1 on API",
+       (StringRef, bool))
+
+ERROR(attr_abi_mismatched_attr,none,
+      "'%0' %select{attribute|modifier}1 in '@abi' should match '%2'",
+      (StringRef, bool, StringRef))
+NOTE(attr_abi_matching_attr_here,none,
+     "%select{should match|matches}0 %select{attribute|modifier}1 "
+     "%select{|implicitly added }2here",
+     (/*matches=*/bool, /*isModifier=*/bool, /*isImplicit=*/bool))
+
+#define TYPE_ORIGIN(KIND_IDX, DECL_IDX) "%select{|%kind" #DECL_IDX " |" \
+                            "self parameter |result |thrown |%error}" #KIND_IDX
+ERROR(attr_abi_mismatched_type,none,
+      TYPE_ORIGIN(0, 1) "type %2 in '@abi' should match %3",
+      (unsigned, Decl *, Type, Type))
+NOTE(attr_abi_should_match_type_here,none,
+     "should match type here", ())
+
+ERROR(attr_abi_mismatched_generic_signature,none,
+      "generic signature '%0' in '@abi' is not compatible with '%1'",
+      (StringRef, StringRef))
+ERROR(attr_abi_missing_generic_signature,none,
+      "declaration in '@abi' should have generic signature compatible with "
+      "'%0'",
+      (StringRef))
+ERROR(attr_abi_extra_generic_signature,none,
+      "declaration in '@abi' should not have generic signature because %0 "
+      "is not generic",
+      (Decl *))
+
+ERROR(attr_abi_mismatched_param_modifier,none,
+      "%select{default |}0%select{attribute|modifier}2 %select{|'%0' }0"
+      "on " TYPE_ORIGIN(3, 4) "in '@abi' is not compatible with "
+      "%select{default|'%1'}1",
+      (StringRef, StringRef, /*isModifier=*/bool, unsigned, Decl *))
+ERROR(attr_abi_no_default_arguments,none,
+      "%kind0 in '@abi' should not have a default argument; it does not "
+      "affect the parameter's ABI",
+      (Decl *))
+
+// These macros insert 'final', 'non-final', or nothing depending on both the
+// current decl and its counterpart, such that 'non-final' is used if the
+// counterpart would be described as 'final' or 'static'. They must be kept in
+// sync with `StaticnessAndFinality`.
+#define NONFINAL_OR_NOTHING(COUNTERPART) \
+      "%select{||non-final |non-final |non-final |%error}" #COUNTERPART
+#define FINAL_OR_NONFINAL_OR_NOTHING(CURRENT, COUNTERPART, FINAL_OK) \
+      "%select{|%select{" NONFINAL_OR_NOTHING(COUNTERPART) \
+                      "|" NONFINAL_OR_NOTHING(COUNTERPART) \
+                      "|final |final ||%error}" #CURRENT "}" #FINAL_OK
+
+ERROR(attr_abi_static_final_mismatch,none,
+      FINAL_OR_NONFINAL_OR_NOTHING(0, 2, 4) "%kind1 in '@abi' should be "
+      FINAL_OR_NONFINAL_OR_NOTHING(2, 0, 4) "%kindonly3 to ensure ABI "
+      "compatibility",
+      (uint8_t, Decl *, uint8_t, Decl *, /*isClass=*/bool))
+
+#undef NONFINAL_OR_NOTHING
+#undef FINAL_OR_NONFINAL_OR_NOTHING
+
+ERROR(attr_abi_failable_mismatch,none,
+      "cannot give %select{non-failable|failable}1 %kind0 the ABI of a "
+      "%select{non-failable|failable}2 %kindonly0",
+      (Decl *, bool, bool))
+
 //===----------------------------------------------------------------------===//
 // MARK: Isolated conformances
 //===----------------------------------------------------------------------===//

include/swift/AST/Types.h

@@ -2378,6 +2378,10 @@ enum class ParamSpecifier : uint8_t {
 
 StringRef getNameForParamSpecifier(ParamSpecifier name);
 
+/// What does \c ParamSpecifier::Default mean for a parameter that's directly
+/// attached to \p VD ? Pass \c nullptr for the value for a closure.
+ParamSpecifier getDefaultParamSpecifier(const ValueDecl *VD);
+
 /// Provide parameter type relevant flags, i.e. variadic, autoclosure, and
 /// escaping.
 class ParameterTypeFlags {

include/swift/Basic/LangOptions.h

@@ -269,6 +269,9 @@ namespace swift {
     /// Emit a remark on early exit in explicit interface build
     bool EnableSkipExplicitInterfaceModuleBuildRemarks = false;
 
+    /// Emit a remark when \c \@abi infers an attribute or modifier.
+    bool EnableABIInferenceRemarks = false;
+
     ///
     /// Support for alternate usage modes
     ///

include/swift/Option/Options.td

@@ -468,6 +468,10 @@ def remark_module_serialization : Flag<["-"], "Rmodule-serialization">,
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Emit remarks about module serialization">;
 
+def remark_abi_inference : Flag<["-"], "Rabi-inference">,
+  Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Emit a remark when an '@abi' attribute adds an attribute or modifier to the ABI declaration based on its presence in the API">;
+
 def emit_tbd : Flag<["-"], "emit-tbd">,
   HelpText<"Emit a TBD file">,
   Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput]>;

lib/AST/ASTMangler.cpp

@@ -1193,11 +1193,9 @@ getOverriddenSwiftProtocolObjCName(const ValueDecl *decl,
     return std::nullopt;
 
   // If there is an 'objc' attribute with a name, use that name.
-  if (auto objc = proto->getAttrs().getAttribute<ObjCAttr>()) {
-    if (auto name = objc->getName()) {
-      llvm::SmallString<4> buffer;
-      return std::string(name->getString(buffer));
-    }
+  if (auto objcName = proto->getExplicitObjCName()) {
+    llvm::SmallString<4> buffer;
+    return std::string(objcName->getString(buffer));
   }
 
   return std::nullopt;
@@ -3379,8 +3377,7 @@ void ASTMangler::appendFunctionSignature(AnyFunctionType *fn,
   }
 }
 
-static ParamSpecifier
-getDefaultOwnership(const ValueDecl *forDecl) {
+ParamSpecifier swift::getDefaultParamSpecifier(const ValueDecl *forDecl) {
   // `consuming` is the default ownership for initializers and setters.
   // Everything else defaults to borrowing.
   if (!forDecl) {
@@ -3451,7 +3448,7 @@ getParameterFlagsForMangling(ParameterTypeFlags flags,
 void ASTMangler::appendFunctionInputType(
     AnyFunctionType *fnType, ArrayRef<AnyFunctionType::Param> params,
     GenericSignature sig, const ValueDecl *forDecl, bool isRecursedInto) {
-  auto defaultSpecifier = getDefaultOwnership(forDecl);
+  auto defaultSpecifier = getDefaultParamSpecifier(forDecl);
 
   switch (params.size()) {
   case 0:

lib/AST/ASTPrinter.cpp

@@ -1284,6 +1284,15 @@ void PrintAST::printAttributes(const Decl *D) {
   // for each decl They cannot be shared across different decls.
   assert(Options.ExcludeCustomAttrList.empty());
 
+  // If there is an `@abi` attr, we need to print it first so that it isn't
+  // affected by subsequent mutation of `Options.ExcludeAttrList`.
+  if (auto abiAttr = attrs.getAttribute<ABIAttr>()) {
+    if (Options.PrintImplicitAttrs && !Options.excludeAttr(abiAttr)) {
+      abiAttr->print(Printer, Options, D);
+      Options.ExcludeAttrList.push_back(DeclAttrKind::ABI);
+    }
+  }
+
   if (Options.PrintSyntheticSILGenName
         && !D->getAttrs().hasAttribute<SILGenNameAttr>()) {
     if (canPrintSyntheticSILGenName(D)) {
@@ -1334,7 +1343,8 @@ void PrintAST::printAttributes(const Decl *D) {
     // Add SPIs to both private and package interfaces
     if (!Options.printPublicInterface() &&
         DeclAttribute::canAttributeAppearOnDeclKind(
-            DeclAttrKind::SPIAccessControl, D->getKind())) {
+            DeclAttrKind::SPIAccessControl, D->getKind()) &&
+        !Options.excludeAttrKind(DeclAttrKind::SPIAccessControl)) {
       interleave(D->getSPIGroups(),
              [&](Identifier spiName) {
                Printer.printAttrName("_spi", true);
@@ -1358,7 +1368,7 @@ void PrintAST::printAttributes(const Decl *D) {
     // If the declaration is implicitly @objc, print the attribute now.
     if (auto VD = dyn_cast<ValueDecl>(D)) {
       if (VD->isObjC() && !isa<EnumElementDecl>(VD) &&
-          !attrs.hasAttribute<ObjCAttr>()) {
+          !attrs.hasAttribute<ObjCAttr>() && ABIRoleInfo(D).providesAPI()) {
         Printer.printAttrName("@objc");
         Printer << " ";
       }

lib/AST/AccessRequests.cpp

@@ -43,6 +43,11 @@ AccessLevel
 AccessLevelRequest::evaluate(Evaluator &evaluator, ValueDecl *D) const {
   assert(!D->hasAccess());
 
+  // ABI decls share the access level of their API decl.
+  auto abiRole = ABIRoleInfo(D);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getFormalAccess();
+
   // Check if the decl has an explicit access control attribute.
   if (auto *AA = D->getAttrs().getAttribute<AccessControlAttr>())
     return AA->getAccess();
@@ -201,6 +206,12 @@ AccessLevel
 SetterAccessLevelRequest::evaluate(Evaluator &evaluator,
                                    AbstractStorageDecl *ASD) const {
   assert(!ASD->Accessors.getInt().hasValue());
+
+  // ABI decls share the access level of their API decl.
+  auto abiRole = ABIRoleInfo(ASD);
+  if (!abiRole.providesAPI() && abiRole.getCounterpart())
+    return abiRole.getCounterpart()->getSetterFormalAccess();
+
   if (auto *SAA = ASD->getAttrs().getAttribute<SetterAccessAttr>())
     return SAA->getAccess();