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

rdar://problem/23415863

llvm-svn: 252187

5 files changed, 57 insertions, 9 deletions

diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 5bf175e3bd9..24d32eea90d 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -518,8 +518,6 @@ def fobjc_runtime_has_weak : Flag<["-"], "fobjc-runtime-has-weak">,
   HelpText<"The target Objective-C runtime supports ARC weak operations">;
 def fobjc_dispatch_method_EQ : Joined<["-"], "fobjc-dispatch-method=">,
   HelpText<"Objective-C dispatch method to use">;
-def fobjc_weak : Flag<["-"], "fobjc-weak">, Group<f_Group>,
-  HelpText<"Enable ARC-style __weak references">;
 def disable_objc_default_synthesize_properties : Flag<["-"], "disable-objc-default-synthesize-properties">,
   HelpText<"disable the default synthesis of Objective-C properties">;
 def fencode_extended_block_signature : Flag<["-"], "fencode-extended-block-signature">,
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 52c54eecb42..65dd87ce438 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -852,6 +852,7 @@ def fno_ms_compatibility : Flag<["-"], "fno-ms-compatibility">, Group<f_Group>,
 def fno_delayed_template_parsing : Flag<["-"], "fno-delayed-template-parsing">, Group<f_Group>;
 def fno_objc_exceptions: Flag<["-"], "fno-objc-exceptions">, Group<f_Group>;
 def fno_objc_legacy_dispatch : Flag<["-"], "fno-objc-legacy-dispatch">, Group<f_Group>;
+def fno_objc_weak : Flag<["-"], "fno-objc-weak">, Group<f_Group>, Flags<[CC1Option]>;
 def fno_omit_frame_pointer : Flag<["-"], "fno-omit-frame-pointer">, Group<f_Group>;
 def fno_operator_names : Flag<["-"], "fno-operator-names">, Group<f_Group>,
   HelpText<"Do not treat C++ operator name keywords as synonyms for operators">,
@@ -921,6 +922,8 @@ def fno_objc_infer_related_result_type : Flag<["-"],
     "do not infer Objective-C related result type based on method family">,
   Flags<[CC1Option]>;
 def fobjc_link_runtime: Flag<["-"], "fobjc-link-runtime">, Group<f_Group>;
+def fobjc_weak : Flag<["-"], "fobjc-weak">, Group<f_Group>, Flags<[CC1Option]>,
+  HelpText<"Enable ARC-style weak references in Objective-C">;
 
 // Objective-C ABI options.
 def fobjc_runtime_EQ : Joined<["-"], "fobjc-runtime=">, Group<f_Group>, Flags<[CC1Option]>,
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))
diff --git a/clang/test/Driver/objc-weak.m b/clang/test/Driver/objc-weak.m
new file mode 100644
index 00000000000..ff60759f2c9
--- /dev/null
+++ b/clang/test/Driver/objc-weak.m
@@ -0,0 +1,27 @@
+// Check miscellaneous Objective-C options.
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fobjc-arc -fobjc-weak 2>&1 | FileCheck %s --check-prefix ARC-WEAK
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fno-objc-weak -fobjc-weak -fobjc-arc  2>&1 | FileCheck %s --check-prefix ARC-WEAK
+// ARC-WEAK: -fobjc-arc
+// ARC-WEAK: -fobjc-weak
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fobjc-arc -fno-objc-weak 2>&1 | FileCheck %s --check-prefix ARC-NO-WEAK
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fobjc-weak -fno-objc-weak -fobjc-arc  2>&1 | FileCheck %s --check-prefix ARC-NO-WEAK
+// ARC-NO-WEAK: -fobjc-arc
+// ARC-NO-WEAK: -fno-objc-weak
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.5 -S -### %s -fobjc-arc -fobjc-weak 2>&1 | FileCheck %s --check-prefix ARC-WEAK-UNSUPPORTED
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.5 -S -### %s -fno-objc-weak -fobjc-weak -fobjc-arc  2>&1 | FileCheck %s --check-prefix ARC-WEAK-UNSUPPORTED
+// ARC-WEAK-UNSUPPORTED: error: -fobjc-weak is not supported on the current deployment target
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fobjc-weak 2>&1 | FileCheck %s --check-prefix MRC-WEAK
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fno-objc-weak -fobjc-weak 2>&1 | FileCheck %s --check-prefix MRC-WEAK
+// MRC-WEAK: -fobjc-weak
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fno-objc-weak 2>&1 | FileCheck %s --check-prefix MRC-NO-WEAK
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.7 -S -### %s -fobjc-weak -fno-objc-weak 2>&1 | FileCheck %s --check-prefix MRC-NO-WEAK
+// MRC-NO-WEAK: -fno-objc-weak
+
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.5 -S -### %s -fobjc-weak 2>&1 | FileCheck %s --check-prefix MRC-WEAK-UNSUPPORTED
+// RUN: %clang -target x86_64-apple-macosx -mmacosx-version-min=10.5 -S -### %s -fno-objc-weak -fobjc-weak 2>&1 | FileCheck %s --check-prefix MRC-WEAK-UNSUPPORTED
+// MRC-WEAK-UNSUPPORTED: error: -fobjc-weak is not supported on the current deployment target