Add a define for the ObjFW runtime ABI version.

This removes __has_feature(objc_msg_lookup_stret), as it is not required
anymore after this patch.

Patch by Jonathan Schleifer!

llvm-svn: 190791

clang/docs/LanguageExtensions.rst

@@ -1255,23 +1255,6 @@ Further examples of these attributes are available in the static analyzer's `lis
 Query for these features with ``__has_attribute(ns_consumed)``,
 ``__has_attribute(ns_returns_retained)``, etc.
 
-objc_msg_lookup_stret
----------------------
-
-Traditionally, if a runtime is used that follows the GNU Objective-C ABI, a
-call to objc_msg_lookup() would be emitted for each message send, which would
-return a pointer to the actual implementation of the method. However,
-objc_msg_lookup() has no information at all about the method signature of the
-actual method. Therefore, certain features like forwarding messages cannot be
-correctly implemented for methods returning structs using objc_msg_lookup(), as
-methods returning structs use a slightly different calling convention.
-
-To work around this, Clang emits calls to objc_msg_lookup_stret() instead for
-methods that return structs if the runtime supports this, allowing the runtime
-to use a different forwarding handler for methods returning structs.
-
-To check if Clang emits calls to objc_msg_lookup_stret(),
-__has_feature(objc_msg_lookup_stret) can be used.
 
 Function Overloading in C
 =========================

clang/lib/Basic/ObjCRuntime.cpp

@@ -71,16 +71,20 @@ bool ObjCRuntime::tryParse(StringRef input) {
     kind = ObjCRuntime::GCC;
   } else if (runtimeName == "objfw") {
     kind = ObjCRuntime::ObjFW;
+    Version = VersionTuple(0, 8);
   } else {
     return true;
   }
   TheKind = kind;
-  
+
   if (dash != StringRef::npos) {
     StringRef verString = input.substr(dash + 1);
-    if (Version.tryParse(verString)) 
+    if (Version.tryParse(verString))
       return true;
   }
 
+  if (kind == ObjCRuntime::ObjFW && Version > VersionTuple(0, 8))
+    Version = VersionTuple(0, 8);
+
   return false;
 }

clang/lib/Frontend/InitPreprocessor.cpp

@@ -408,6 +408,22 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
     if (LangOpts.ObjCRuntime.isNeXTFamily())
       Builder.defineMacro("__NEXT_RUNTIME__");
 
+    if (LangOpts.ObjCRuntime.getKind() == ObjCRuntime::ObjFW) {
+      VersionTuple tuple = LangOpts.ObjCRuntime.getVersion();
+
+      unsigned minor = 0;
+      if (tuple.getMinor().hasValue())
+        minor = tuple.getMinor().getValue();
+
+      unsigned subminor = 0;
+      if (tuple.getSubminor().hasValue())
+        subminor = tuple.getSubminor().getValue();
+
+      Builder.defineMacro("__OBJFW_RUNTIME_ABI__",
+                          Twine(tuple.getMajor() * 10000 + minor * 100 +
+                                subminor));
+    }
+
     Builder.defineMacro("IBOutlet", "__attribute__((iboutlet))");
     Builder.defineMacro("IBOutletCollection(ClassName)",
                         "__attribute__((iboutletcollection(ClassName)))");

clang/lib/Lex/PPMacroExpansion.cpp

@@ -920,7 +920,6 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
            .Case("objc_nonfragile_abi", LangOpts.ObjCRuntime.isNonFragile())
            .Case("objc_property_explicit_atomic", true) // Does clang support explicit "atomic" keyword?
            .Case("objc_weak_class", LangOpts.ObjCRuntime.hasWeakClassImport())
-           .Case("objc_msg_lookup_stret", LangOpts.ObjCRuntime.getKind() == ObjCRuntime::ObjFW)
            .Case("ownership_holds", true)
            .Case("ownership_returns", true)
            .Case("ownership_takes", true)

clang/test/CodeGenObjC/stret_lookup.m

@@ -11,8 +11,8 @@ struct test {
 @end
 void test0(void) {
   struct test t;
-#if (defined(STRET) && __has_feature(objc_msg_lookup_stret)) || \
-    (!defined(STRET) && !__has_feature(objc_msg_lookup_stret))
+#if (defined(STRET) && defined(__OBJFW_RUNTIME_ABI__)) || \
+    (!defined(STRET) && !defined(__OBJFW_RUNTIME_ABI__))
   t = [Test0 test];
 #endif
   (void)t;