Filter bad attrs out of module interface @abis

When printing an `@abi` attribute’s decl, we now filter out any attrs that are not valid in that position. Fixes a broken test.

Author: beccadax

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),

lib/AST/Attr.cpp

@@ -68,6 +68,15 @@ static_assert(IsTriviallyDestructible<DeclAttributes>::value,
   static_assert(TypeAttrKind::Id <= TypeAttrKind::Last_TypeAttr);
 #include "swift/AST/TypeAttr.def"
 
+LLVM_ATTRIBUTE_USED StringRef swift::getDeclAttrKindID(DeclAttrKind kind) {
+    switch (kind) {
+#define DECL_ATTR(_, CLASS, ...)                               \
+  case DeclAttrKind::CLASS:                                    \
+    return #CLASS;
+#include "swift/AST/DeclAttr.def"
+  }
+}
+
 StringRef swift::getAccessLevelSpelling(AccessLevel value) {
   switch (value) {
   case AccessLevel::Private: return "private";
@@ -1676,8 +1685,24 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
       abiDecl = cast<PatternBindingDecl>(abiDecl)
                     ->getVarAtSimilarStructuralPosition(
                                       const_cast<VarDecl *>(cast<VarDecl>(D)));
-    if (abiDecl)
-      abiDecl->print(Printer, Options);
+    if (abiDecl) {
+      auto optionsCopy = Options;
+
+      // Don't print any attributes marked with `ForbiddenInABIAttr`.
+      for (auto rawAttrKind : range(0, unsigned(DeclAttrKind::Last_DeclAttr))) {
+        DeclAttrKind attrKind{rawAttrKind}; 
+        if (!(DeclAttribute::getBehaviors(attrKind)
+                & DeclAttribute::ForbiddenInABIAttr))
+          continue;
+
+        if (attrKind == DeclAttrKind::AccessControl)
+          optionsCopy.PrintAccess = false;
+        else
+          optionsCopy.ExcludeAttrList.push_back(attrKind);
+      }
+
+      abiDecl->print(Printer, optionsCopy);
+    }
     Printer << ")";
 
     break;
@@ -1742,7 +1767,7 @@ uint64_t DeclAttribute::getBehaviors(DeclAttrKind DK) {
     return BEHAVIORS;
 #include "swift/AST/DeclAttr.def"
   }
-  llvm_unreachable("bad DeclAttrKind");
+  return 0;
 }
 
 std::optional<Feature> DeclAttribute::getRequiredFeature(DeclAttrKind DK) {

test/ModuleInterface/attrs.swift

@@ -35,20 +35,20 @@ internal func __specialize_someGenericFunction<T>(_ t: T) -> Int {
     fatalError("don't call")
 }
 
-@abi(public func __abi__abiAttrOnFunction(param: Int))
+@abi(func __abi__abiAttrOnFunction(param: Int))
 public func abiAttrOnFunction(param: Int) {}
 // CHECK: #if {{.*}} $ABIAttribute
-// CHECK: @abi(public func __abi__abiAttrOnFunction(param: Swift.Int))
+// CHECK: @abi(func __abi__abiAttrOnFunction(param: Swift.Int))
 // CHECK: public func abiAttrOnFunction(param: Swift.Int)
 // CHECK: #else
 // CHECK: @_silgen_name("$s5attrs07__abi__B14AttrOnFunction5paramySi_tF")
 // CHECK: public func abiAttrOnFunction(param: Swift.Int)
 // CHECK: #endif
 
-@abi(public let __abi__abiAttrOnVar: Int)
+@abi(let __abi__abiAttrOnVar: Int)
 public var abiAttrOnVar: Int = 42
 // CHECK: #if {{.*}} $ABIAttribute
-// CHECK: @abi(public var __abi__abiAttrOnVar: Swift.Int)
+// CHECK: @abi(var __abi__abiAttrOnVar: Swift.Int)
 // CHECK: public var abiAttrOnVar: Swift.Int
 // CHECK: #else
 // CHECK: @available(*, unavailable, message: "this compiler cannot match the ABI specified by the @abi attribute")