Screw around with ObjCRuntime some more, changing the

diagnostics for bad deployment targets and adding a few
more predicates.  Includes a patch by Jonathan Schleifer
to enable ARC for ObjFW.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162252 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticDriverKinds.td

@@ -91,10 +91,10 @@ def err_drv_invalid_arch_for_deployment_target : Error<
   "invalid architecture '%0' for deployment target '%1'">;
 def err_drv_objc_gc_arr : Error<
   "cannot specify both '-fobjc-arc' and '%0'">;
-def err_arc_nonfragile_abi : Error<
-  "-fobjc-arc is not supported with legacy abi">;
-def err_arc_unsupported : Error<
-  "-fobjc-arc is not supported on current deployment target">;
+def err_arc_unsupported_on_runtime : Error<
+  "-fobjc-arc is not supported on platforms using the legacy runtime">;
+def err_arc_unsupported_on_toolchain : Error<
+  "-fobjc-arc is not supported on %select{versions of Mac OS prior to 10.6}0">;
 def err_drv_mg_requires_m_or_mm : Error<
   "option '-MG' requires '-M' or '-MM'">;
 def err_drv_asan_android_requires_pie : Error<

include/clang/Basic/LangOptions.def

@@ -135,7 +135,7 @@ LANGOPT(DefaultFPContract , 1, 0, "FP_CONTRACT")
 LANGOPT(NoBitFieldTypeAlign , 1, 0, "bit-field type alignment")
 LANGOPT(HexagonQdsp6Compat , 1, 0, "hexagon-qdsp6 backward compatibility")
 LANGOPT(ObjCAutoRefCount , 1, 0, "Objective-C automated reference counting")
-LANGOPT(ObjCRuntimeHasWeak , 1, 0, "__weak support in the ARC runtime")
+LANGOPT(ObjCARCWeak         , 1, 0, "__weak support in the ARC runtime")
 LANGOPT(FakeAddressSpaceMap , 1, 0, "OpenCL fake address space map")
 
 LANGOPT(MRTD , 1, 0, "-mrtd calling convention")

include/clang/Basic/ObjCRuntime.h

@@ -126,12 +126,25 @@ public:
     return !isGNUFamily();
   }
 
+  /// \brief Does this runtime allow ARC at all?
+  bool allowsARC() const {
+    switch (getKind()) {
+    case FragileMacOSX: return false;
+    case MacOSX: return true;
+    case iOS: return true;
+    case GCC: return false;
+    case GNUstep: return true;
+    case ObjFW: return true;
+    }
+    llvm_unreachable("bad kind");
+  }
+
   /// \brief Does this runtime natively provide the ARC entrypoints? 
   ///
   /// ARC cannot be directly supported on a platform that does not provide
   /// these entrypoints, although it may be supportable via a stub
   /// library.
-  bool hasARC() const {
+  bool hasNativeARC() const {
     switch (getKind()) {
     case FragileMacOSX: return false;
     case MacOSX: return getVersion() >= VersionTuple(10, 7);
@@ -139,16 +152,22 @@ public:
 
     case GCC: return false;
     case GNUstep: return getVersion() >= VersionTuple(1, 6);
-    case ObjFW: return false; // XXX: this will change soon
+    case ObjFW: return true;
     }
     llvm_unreachable("bad kind");
   }
 
+  /// Does this runtime allow the use of __weak?
+  bool allowsWeak() const {
+    return hasNativeWeak();
+  }
+
   /// \brief Does this runtime natively provide ARC-compliant 'weak'
   /// entrypoints?
-  bool hasWeak() const {
-    // Right now, this is always equivalent to the ARC decision.
-    return hasARC();
+  bool hasNativeWeak() const {
+    // Right now, this is always equivalent to whether the runtime
+    // natively supports ARC decision.
+    return hasNativeARC();
   }
 
   /// \brief Does this runtime directly support the subscripting methods?
@@ -226,6 +245,7 @@ public:
     }
     llvm_unreachable("bad kind");
   }
+
   /// \brief Does this runtime use zero-cost exceptions?
   bool hasUnwindExceptions() const {
     switch (getKind()) {

include/clang/Driver/ToolChain.h

@@ -183,8 +183,8 @@ public:
   /// Does this tool chain support Objective-C garbage collection.
   virtual bool SupportsObjCGC() const { return true; }
 
-  /// Does this tool chain support Objective-C ARC.
-  virtual bool SupportsObjCARC() const { return true; }
+  /// Complain if this tool chain doesn't support Objective-C ARC.
+  virtual void CheckObjCARC() const {}
 
   /// UseDwarfDebugFlags - Embed the compile options to clang into the Dwarf
   /// compile unit information.

lib/ARCMigrate/ARCMT.cpp

@@ -237,7 +237,7 @@ createInvocationForMigration(CompilerInvocation &origCI) {
   WarnOpts.push_back("error=arc-unsafe-retained-assign");
   CInvok->getDiagnosticOpts().Warnings = llvm_move(WarnOpts);
 
-  CInvok->getLangOpts()->ObjCRuntimeHasWeak = HasARCRuntime(origCI);
+  CInvok->getLangOpts()->ObjCARCWeak = HasARCRuntime(origCI);
 
   return CInvok.take();
 }

lib/ARCMigrate/Transforms.cpp

@@ -40,7 +40,7 @@ bool MigrationPass::CFBridgingFunctionsDefined() {
 
 bool trans::canApplyWeak(ASTContext &Ctx, QualType type,
                          bool AllowOnUnknownClass) {
-  if (!Ctx.getLangOpts().ObjCRuntimeHasWeak)
+  if (!Ctx.getLangOpts().ObjCARCWeak)
     return false;
 
   QualType T = type;

lib/CodeGen/CGObjC.cpp

@@ -1706,7 +1706,7 @@ static llvm::Constant *createARCRuntimeFunction(CodeGenModule &CGM,
   // references to the runtime support library.  We don't really
   // permit this to fail, but we need a particular relocation style.
   if (llvm::Function *f = dyn_cast<llvm::Function>(fn)) {
-    if (!CGM.getLangOpts().ObjCRuntime.hasARC())
+    if (!CGM.getLangOpts().ObjCRuntime.hasNativeARC())
       f->setLinkage(llvm::Function::ExternalWeakLinkage);
     // set nonlazybind attribute for these APIs for performance.
     if (fnName == "objc_retain" || fnName  == "objc_release")
@@ -2739,7 +2739,7 @@ void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
 
   // Keep track of the current cleanup stack depth.
   RunCleanupsScope Scope(*this);
-  if (CGM.getLangOpts().ObjCRuntime.hasARC()) {
+  if (CGM.getLangOpts().ObjCRuntime.hasNativeARC()) {
     llvm::Value *token = EmitObjCAutoreleasePoolPush();
     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
   } else {

lib/CodeGen/CGObjCGNU.cpp

@@ -653,11 +653,40 @@ class CGObjCGNUstep : public CGObjCGNU {
     }
 };
 
-/// The ObjFW runtime, which closely follows the GCC runtime's
-/// compiler ABI.  Support here is due to Jonathan Schleifer, the
-/// ObjFW maintainer.
-class CGObjCObjFW : public CGObjCGCC {
-  /// Emit class references unconditionally as direct symbol references.
+/// Support for the ObjFW runtime. Support here is due to
+/// Jonathan Schleifer <js@webkeks.org>, the ObjFW maintainer.
+class CGObjCObjFW: public CGObjCGNU {
+protected:
+  /// The GCC ABI message lookup function.  Returns an IMP pointing to the
+  /// method implementation for this message.
+  LazyRuntimeFunction MsgLookupFn;
+  /// The GCC ABI superclass message lookup function.  Takes a pointer to a
+  /// structure describing the receiver and the class, and a selector as
+  /// arguments.  Returns the IMP for the corresponding method.
+  LazyRuntimeFunction MsgLookupSuperFn;
+
+  virtual llvm::Value *LookupIMP(CodeGenFunction &CGF,
+                                 llvm::Value *&Receiver,
+                                 llvm::Value *cmd,
+                                 llvm::MDNode *node) {
+    CGBuilderTy &Builder = CGF.Builder;
+    llvm::Value *args[] = {
+            EnforceType(Builder, Receiver, IdTy),
+            EnforceType(Builder, cmd, SelectorTy) };
+    llvm::CallSite imp = CGF.EmitCallOrInvoke(MsgLookupFn, args);
+    imp->setMetadata(msgSendMDKind, node);
+    return imp.getInstruction();
+  }
+
+  virtual llvm::Value *LookupIMPSuper(CodeGenFunction &CGF,
+                                      llvm::Value *ObjCSuper,
+                                      llvm::Value *cmd) {
+      CGBuilderTy &Builder = CGF.Builder;
+      llvm::Value *lookupArgs[] = {EnforceType(Builder, ObjCSuper,
+          PtrToObjCSuperTy), cmd};
+      return Builder.CreateCall(MsgLookupSuperFn, lookupArgs);
+    }
+
   virtual llvm::Value *GetClassNamed(CGBuilderTy &Builder,
                                      const std::string &Name, bool isWeak) {
     if (isWeak)
@@ -678,7 +707,13 @@ class CGObjCObjFW : public CGObjCGCC {
   }
 
 public:
-  CGObjCObjFW(CodeGenModule &Mod): CGObjCGCC(Mod) {}
+  CGObjCObjFW(CodeGenModule &Mod): CGObjCGNU(Mod, 9, 3) {
+    // IMP objc_msg_lookup(id, SEL);
+    MsgLookupFn.init(&CGM, "objc_msg_lookup", IMPTy, IdTy, SelectorTy, NULL);
+    // IMP objc_msg_lookup_super(struct objc_super*, SEL);
+    MsgLookupSuperFn.init(&CGM, "objc_msg_lookup_super", IMPTy,
+                          PtrToObjCSuperTy, SelectorTy, NULL);
+  }
 };
 } // end anonymous namespace
 

lib/Driver/ToolChains.cpp

@@ -951,8 +951,11 @@ bool Darwin::SupportsObjCGC() const {
   return !isTargetIPhoneOS();
 }
 
-bool Darwin::SupportsObjCARC() const {
-  return isTargetIPhoneOS() || !isMacosxVersionLT(10, 6);
+void Darwin::CheckObjCARC() const {
+  if (isTargetIPhoneOS() || !isMacosxVersionLT(10, 6))
+    return;
+  getDriver().Diag(diag::err_arc_unsupported_on_toolchain)
+    << 0; // "versions of Mac OS X prior to 10.6"
 }
 
 std::string

lib/Driver/ToolChains.h

@@ -354,7 +354,7 @@ public:
 
   virtual bool SupportsObjCGC() const;
 
-  virtual bool SupportsObjCARC() const;
+  virtual void CheckObjCARC() const;
 
   virtual bool UseDwarfDebugFlags() const;
 

lib/Driver/Tools.cpp

@@ -2541,8 +2541,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // NOTE: This logic is duplicated in ToolChains.cpp.
   bool ARC = isObjCAutoRefCount(Args);
   if (ARC) {
-    if (!getToolChain().SupportsObjCARC())
-      D.Diag(diag::err_arc_unsupported);
+    getToolChain().CheckObjCARC();
 
     CmdArgs.push_back("-fobjc-arc");
 
@@ -4481,7 +4480,7 @@ void darwin::Link::ConstructJob(Compilation &C, const JobAction &JA,
       ObjCRuntime runtime =
         getDarwinToolChain().getDefaultObjCRuntime(/*nonfragile*/ true);
       // We use arclite library for both ARC and subscripting support.
-      if ((!runtime.hasARC() && isObjCAutoRefCount(Args)) ||
+      if ((!runtime.hasNativeARC() && isObjCAutoRefCount(Args)) ||
           !runtime.hasSubscripting())
         getDarwinToolChain().AddLinkARCArgs(Args, CmdArgs);
     }

lib/Frontend/CompilerInvocation.cpp

@@ -812,7 +812,7 @@ static void LangOptsToArgs(const LangOptions &Opts, ToArgsList &Res) {
   Res.push_back("-fobjc-runtime=" + Opts.ObjCRuntime.getAsString());
   if (Opts.ObjCAutoRefCount)
     Res.push_back("-fobjc-arc");
-  if (Opts.ObjCRuntimeHasWeak)
+  if (Opts.ObjCARCWeak)
     Res.push_back("-fobjc-runtime-has-weak");
   if (!Opts.ObjCInferRelatedResultType)
     Res.push_back("-fno-objc-infer-related-result-type");
@@ -1941,13 +1941,15 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Opts.setGC(LangOptions::HybridGC);
     else if (Args.hasArg(OPT_fobjc_arc)) {
       Opts.ObjCAutoRefCount = 1;
-      if (!Opts.ObjCRuntime.isNonFragile())
-        Diags.Report(diag::err_arc_nonfragile_abi);
-    }
+      if (!Opts.ObjCRuntime.allowsARC())
+        Diags.Report(diag::err_arc_unsupported_on_runtime);
 
-    Opts.ObjCRuntimeHasWeak = Opts.ObjCRuntime.hasWeak();
-    if (Args.hasArg(OPT_fobjc_runtime_has_weak))
-      Opts.ObjCRuntimeHasWeak = 1;
+      // Only set ObjCARCWeak if ARC is enabled.
+      if (Args.hasArg(OPT_fobjc_runtime_has_weak))
+        Opts.ObjCARCWeak = 1;
+      else
+        Opts.ObjCARCWeak = Opts.ObjCRuntime.allowsWeak();
+    }
 
     if (Args.hasArg(OPT_fno_objc_infer_related_result_type))
       Opts.ObjCInferRelatedResultType = 0;

lib/Frontend/InitPreprocessor.cpp

@@ -247,7 +247,7 @@ static void AddObjCXXARCLibstdcxxDefines(const LangOptions &LangOpts,
         << "};\n"
         << "\n";
       
-    if (LangOpts.ObjCRuntimeHasWeak) {
+    if (LangOpts.ObjCARCWeak) {
       Out << "template<typename _Tp>\n"
           << "struct __is_scalar<__attribute__((objc_ownership(weak))) _Tp> {\n"
           << "  enum { __value = 0 };\n"

lib/Lex/PPMacroExpansion.cpp

@@ -641,8 +641,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
            // Objective-C features
            .Case("objc_arr", LangOpts.ObjCAutoRefCount) // FIXME: REMOVE?
            .Case("objc_arc", LangOpts.ObjCAutoRefCount)
-           .Case("objc_arc_weak", LangOpts.ObjCAutoRefCount && 
-                 LangOpts.ObjCRuntimeHasWeak)
+           .Case("objc_arc_weak", LangOpts.ObjCARCWeak)
            .Case("objc_default_synthesize_properties", LangOpts.ObjC2)
            .Case("objc_fixed_enum", LangOpts.ObjC2)
            .Case("objc_instancetype", LangOpts.ObjC2)

lib/Sema/SemaCodeComplete.cpp

@@ -4649,8 +4649,7 @@ void Sema::CodeCompleteObjCPropertyFlags(Scope *S, ObjCDeclSpec &ODS) {
     Results.AddResult(CodeCompletionResult("atomic"));
 
   // Only suggest "weak" if we're compiling for ARC-with-weak-references or GC.
-  if ((getLangOpts().ObjCAutoRefCount && getLangOpts().ObjCRuntimeHasWeak) ||
-      getLangOpts().getGC() != LangOptions::NonGC)
+  if (getLangOpts().ObjCARCWeak || getLangOpts().getGC() != LangOptions::NonGC)
     if (!ObjCPropertyFlagConflicts(Attributes, ObjCDeclSpec::DQ_PR_weak))
       Results.AddResult(CodeCompletionResult("weak"));
 

lib/Sema/SemaObjCProperty.cpp

@@ -880,7 +880,7 @@ Decl *Sema::ActOnPropertyImplDecl(Scope *S,
                 Diag(property->getLocation(), diag::note_property_declare);
                 err = true;
               }
-            if (!err && !getLangOpts().ObjCRuntimeHasWeak) {
+            if (!err && !getLangOpts().ObjCARCWeak) {
               Diag(PropertyDiagLoc, diag::err_arc_weak_no_runtime);
               Diag(property->getLocation(), diag::note_property_declare);
             }

lib/Sema/SemaType.cpp

@@ -3588,7 +3588,7 @@ static bool handleObjCOwnershipTypeAttr(TypeProcessingState &state,
 
   // Forbid __weak if the runtime doesn't support it.
   if (lifetime == Qualifiers::OCL_Weak &&
-      !S.getLangOpts().ObjCRuntimeHasWeak && !NonObjCPointer) {
+      !S.getLangOpts().ObjCARCWeak && !NonObjCPointer) {
 
     // Actually, delay this until we know what we're parsing.
     if (S.DelayedDiagnostics.shouldDelayDiagnostics()) {

test/Driver/arc.c

@@ -8,10 +8,10 @@
 // Just to test clang is working.
 # foo
 
-// CHECK: error: -fobjc-arc is not supported with legacy abi
+// CHECK: error: -fobjc-arc is not supported on platforms using the legacy runtime
 // CHECK-NOT: invalid preprocessing directive
 
-// NOTOBJC-NOT: error: -fobjc-arc is not supported with legacy abi
+// NOTOBJC-NOT: error: -fobjc-arc is not supported on platforms using the legacy runtime
 // NOTOBJC: invalid preprocessing directive
 
-// UNSUPPORTED: error: -fobjc-arc is not supported on current deployment target
+// UNSUPPORTED: error: -fobjc-arc is not supported on versions of Mac OS prior to 10.6