Share string literal for spi_available attribute name

Author: nkcsgexi

include/swift/Strings.h

@@ -64,6 +64,10 @@ constexpr static const StringLiteral BUILTIN_TYPE_NAME_PREFIX = "Builtin.";
 constexpr static const StringLiteral CLANG_MODULE_DEFUALT_SPI_GROUP_NAME =
   "OBJC_DEFAULT_SPI_GROUP";
 
+/// The attribute name for @_spi_available
+constexpr static const StringLiteral SPI_AVAILABLE_ATTRNAME =
+  "_spi_available";
+
 /// A composition class containing a StringLiteral for the names of
 /// Swift builtins. The reason we use this is to ensure that we when
 /// necessary slice off the "Builtin." prefix from these names in a

lib/AST/Attr.cpp

@@ -29,6 +29,7 @@
 #include "swift/AST/Types.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/QuotedString.h"
+#include "swift/Strings.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -126,7 +127,7 @@ DeclAttrKind DeclAttribute::getAttrKindFromString(StringRef Str) {
 #define DECL_ATTR(X, CLASS, ...) .Case(#X, DAK_##CLASS)
 #define DECL_ATTR_ALIAS(X, CLASS) .Case(#X, DAK_##CLASS)
 #include "swift/AST/Attr.def"
-  .Case("_spi_available", DAK_Available)
+  .Case(SPI_AVAILABLE_ATTRNAME, DAK_Available)
   .Default(DAK_Count);
 }
 
@@ -982,7 +983,12 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
       Printer << ", unavailable)";
       break;
     }
-    Printer.printAttrName(Attr->IsSPI ? "@_spi_available": "@available");
+    if (Attr->IsSPI) {
+      std::string atSPI = (llvm::Twine("@") + SPI_AVAILABLE_ATTRNAME).str();
+      Printer.printAttrName(atSPI);
+    } else {
+      Printer.printAttrName("@available");
+    }
     Printer << "(";
     printAvailableAttr(Attr, Printer, Options);
     Printer << ")";

lib/Parse/ParseDecl.cpp

@@ -21,6 +21,7 @@
 #include "swift/Parse/SyntaxParsingContext.h"
 #include "swift/Syntax/SyntaxKind.h"
 #include "swift/Subsystems.h"
+#include "swift/Strings.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Attr.h"
 #include "swift/AST/GenericParamList.h"
@@ -574,7 +575,7 @@ ParserResult<AvailableAttr> Parser::parseExtendedAvailabilitySpecList(
                 Obsoleted.Version, Obsoleted.Range,
                 PlatformAgnostic,
                 /*Implicit=*/false,
-                AttrName == "_spi_available");
+                AttrName == SPI_AVAILABLE_ATTRNAME);
   return makeParserResult(Attr);
 
 }
@@ -860,7 +861,7 @@ bool Parser::parseAvailability(
           /*Obsoleted=*/llvm::VersionTuple(),
           /*ObsoletedRange=*/SourceRange(), PlatformAgnostic,
           /*Implicit=*/false,
-          AttrName == "_spi_available"));
+          AttrName == SPI_AVAILABLE_ATTRNAME));
     }
 
     return true;