Add clang support for Objective-C application extensions.

This adds the -fapplication-extension option, along with the
ios_app_extension and macosx_app_extension availability attributes.
Patch by Ted Kremenek

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@230989 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/Attr.td

@@ -442,6 +442,8 @@ def Availability : InheritableAttr {
     return llvm::StringSwitch<llvm::StringRef>(Platform)
              .Case("ios", "iOS")
              .Case("macosx", "OS X")
+             .Case("ios_app_extension", "iOS (App Extension)")
+             .Case("macosx_app_extension", "OS X (App Extension)")
              .Default(llvm::StringRef());
 } }];
   let HasCustomParsing = 1;

include/clang/Basic/LangOptions.def

@@ -84,6 +84,7 @@ BENIGN_LANGOPT(EncodeExtendedBlockSig , 1, 0,
                "Encoding extended block type signature")
 BENIGN_LANGOPT(ObjCInferRelatedResultType , 1, 1,
                "Objective-C related result type inference")
+LANGOPT(AppExt , 1, 0, "Objective-C App Extension")
 LANGOPT(Trigraphs         , 1, 0,"trigraphs")
 LANGOPT(LineComment       , 1, 0, "'//' comments")
 LANGOPT(Bool              , 1, 0, "bool, true, and false keywords")

include/clang/Driver/Options.td

@@ -819,6 +819,11 @@ def fobjc_atdefs : Flag<["-"], "fobjc-atdefs">, Group<clang_ignored_f_Group>;
 def fobjc_call_cxx_cdtors : Flag<["-"], "fobjc-call-cxx-cdtors">, Group<clang_ignored_f_Group>;
 def fobjc_exceptions: Flag<["-"], "fobjc-exceptions">, Group<f_Group>,
   HelpText<"Enable Objective-C exceptions">, Flags<[CC1Option]>;
+def fapplication_extension : Flag<["-"], "fapplication-extension">,
+  Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Restrict code to those available for App Extensions">;
+def fno_application_extension : Flag<["-"], "fno-application-extension">,
+  Group<f_Group>;
 
 def fobjc_gc_only : Flag<["-"], "fobjc-gc-only">, Group<f_Group>, Flags<[CC1Option]>,
   HelpText<"Use GC exclusively for Objective-C related memory management">;

lib/AST/DeclBase.cpp

@@ -336,20 +336,34 @@ bool Decl::isReferenced() const {
 static AvailabilityResult CheckAvailability(ASTContext &Context,
                                             const AvailabilityAttr *A,
                                             std::string *Message) {
-  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
-  StringRef PrettyPlatformName
-    = AvailabilityAttr::getPrettyPlatformName(TargetPlatform);
-  if (PrettyPlatformName.empty())
-    PrettyPlatformName = TargetPlatform;
+  VersionTuple TargetMinVersion =
+    Context.getTargetInfo().getPlatformMinVersion();
 
-  VersionTuple TargetMinVersion = Context.getTargetInfo().getPlatformMinVersion();
   if (TargetMinVersion.empty())
     return AR_Available;
 
+  // Check if this is an App Extension "platform", and if so chop off
+  // the suffix for matching with the actual platform.
+  StringRef ActualPlatform = A->getPlatform()->getName();
+  StringRef RealizedPlatform = ActualPlatform;
+  if (Context.getLangOpts().AppExt) {
+    size_t suffix = RealizedPlatform.rfind("_app_extension");
+    if (suffix != StringRef::npos)
+      RealizedPlatform = RealizedPlatform.slice(0, suffix);
+  }
+
+  StringRef TargetPlatform = Context.getTargetInfo().getPlatformName();
+
   // Match the platform name.
-  if (A->getPlatform()->getName() != TargetPlatform)
+  if (RealizedPlatform != TargetPlatform)
     return AR_Available;
-  
+
+  StringRef PrettyPlatformName
+    = AvailabilityAttr::getPrettyPlatformName(ActualPlatform);
+
+  if (PrettyPlatformName.empty())
+    PrettyPlatformName = ActualPlatform;
+
   std::string HintMessage;
   if (!A->getMessage().empty()) {
     HintMessage = " - ";

lib/Driver/Tools.cpp

@@ -4216,6 +4216,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  if (Args.hasFlag(options::OPT_fapplication_extension,
+                   options::OPT_fno_application_extension, false))
+    CmdArgs.push_back("-fapplication-extension");
+
   // Handle GCC-style exception args.
   if (!C.getDriver().IsCLMode())
     addExceptionArgs(Args, InputType, getToolChain(), KernelOrKext,
@@ -5811,6 +5815,12 @@ void darwin::Link::AddLinkArgs(Compilation &C,
   if (Args.hasArg(options::OPT_rdynamic) && Version[0] >= 137)
     CmdArgs.push_back("-export_dynamic");
 
+  // If we are using App Extension restrictions, pass a flag to the linker
+  // telling it that the compiled code has been audited.
+  if (Args.hasFlag(options::OPT_fapplication_extension,
+                   options::OPT_fno_application_extension, false))
+    CmdArgs.push_back("-application_extension");
+
   // If we are using LTO, then automatically create a temporary file path for
   // the linker to use, so that it's lifetime will extend past a possible
   // dsymutil step.

lib/Frontend/CompilerInvocation.cpp

@@ -1578,6 +1578,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DebuggerObjCLiteral = Args.hasArg(OPT_fdebugger_objc_literal);
   Opts.ApplePragmaPack = Args.hasArg(OPT_fapple_pragma_pack);
   Opts.CurrentModule = Args.getLastArgValue(OPT_fmodule_name);
+  Opts.AppExt = Args.hasArg(OPT_fapplication_extension);
   Opts.ImplementationOfModule =
       Args.getLastArgValue(OPT_fmodule_implementation_of);
   Opts.ModuleFeatures = Args.getAllArgValues(OPT_fmodule_feature);

lib/Lex/PPMacroExpansion.cpp

@@ -868,6 +868,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
       .Case("attribute_analyzer_noreturn", true)
       .Case("attribute_availability", true)
       .Case("attribute_availability_with_message", true)
+      .Case("attribute_availability_app_extension", true)
       .Case("attribute_cf_returns_not_retained", true)
       .Case("attribute_cf_returns_retained", true)
       .Case("attribute_deprecated_with_message", true)

test/Sema/attr-availability-app-extensions.c

@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.9.0 -fsyntax-only -fapplication-extension %s -verify
+// RUN: %clang_cc1 -triple armv7-apple-ios9.0 -fsyntax-only -fapplication-extension %s -verify
+
+#if __has_feature(attribute_availability_app_extension)
+ __attribute__((availability(macosx_app_extension,unavailable)))
+ __attribute__((availability(ios_app_extension,unavailable)))
+#endif
+void f0(int); // expected-note {{'f0' has been explicitly marked unavailable here}}
+
+__attribute__((availability(macosx,unavailable)))
+__attribute__((availability(ios,unavailable)))
+void f1(int); // expected-note {{'f1' has been explicitly marked unavailable here}}
+
+void test() {
+  f0(1); // expected-error {{'f0' is unavailable: not available on}}
+  f1(1); // expected-error {{'f1' is unavailable}}
+}
+