After some discussion, promote -fobjc-weak to a driver option.

rdar://problem/23415863

llvm-svn: 252187

2 files changed, 27 insertions, 7 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d3276b9ae39..03d4c6be612 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -4816,6 +4816,23 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  // Pass down -fobjc-weak or -fno-objc-weak if present.
+  if (types::isObjC(InputType)) {
+    auto WeakArg = Args.getLastArg(options::OPT_fobjc_weak,
+                                   options::OPT_fno_objc_weak);
+    if (!WeakArg) {
+      // nothing to do
+    } else if (GCArg) {
+      if (WeakArg->getOption().matches(options::OPT_fobjc_weak))
+        D.Diag(diag::err_objc_weak_with_gc);
+    } else if (!objcRuntime.allowsWeak()) {
+      if (WeakArg->getOption().matches(options::OPT_fobjc_weak))
+        D.Diag(diag::err_objc_weak_unsupported);
+    } else {
+      WeakArg->render(Args, CmdArgs);
+    }
+  }
+
   if (Args.hasFlag(options::OPT_fapplication_extension,
                    options::OPT_fno_application_extension, false))
     CmdArgs.push_back("-fapplication-extension");
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 468cc5746ce..7844b100d91 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1483,16 +1483,19 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Opts.ObjCWeakRuntime = Opts.ObjCRuntime.allowsWeak();
 
     // ObjCWeak determines whether __weak is actually enabled.
-    if (Opts.ObjCAutoRefCount) {
-      Opts.ObjCWeak = Opts.ObjCWeakRuntime;
-    } else if (Args.hasArg(OPT_fobjc_weak)) {
-      if (Opts.getGC() != LangOptions::NonGC) {
+    // Note that we allow -fno-objc-weak to disable this even in ARC mode.
+    if (auto weakArg = Args.getLastArg(OPT_fobjc_weak, OPT_fno_objc_weak)) {
+      if (!weakArg->getOption().matches(OPT_fobjc_weak)) {
+        assert(!Opts.ObjCWeak);
+      } else if (Opts.getGC() != LangOptions::NonGC) {
         Diags.Report(diag::err_objc_weak_with_gc);
-      } else if (Opts.ObjCWeakRuntime) {
-        Opts.ObjCWeak = true;
-      } else {
+      } else if (!Opts.ObjCWeakRuntime) {
         Diags.Report(diag::err_objc_weak_unsupported);
+      } else {
+        Opts.ObjCWeak = 1;
       }
+    } else if (Opts.ObjCAutoRefCount) {
+      Opts.ObjCWeak = Opts.ObjCWeakRuntime;
     }
 
     if (Args.hasArg(OPT_fno_objc_infer_related_result_type))