Change the driver's logic about Objective-C runtimes: abstract out a

structure to hold inferred information, then propagate each invididual
bit down to -cc1.  Separate the bits of "supports weak" and "has a native
ARC runtime";  make the latter a CodeGenOption.

The tool chain is still driving this decision, because it's the place that
has the required deployment target information on Darwin, but at least it's
better-factored now.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134453 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rjmccall

include/clang/Basic/LangOptions.h

@@ -131,7 +131,7 @@ class LangOptions {
   // FIXME: This is just a temporary option, for testing purposes.
   unsigned NoBitFieldTypeAlign : 1;
   unsigned ObjCAutoRefCount : 1; // Objective C automated reference counting
-  unsigned ObjCNoAutoRefCountRuntime : 1; // ARC w/o extra runtime support
+  unsigned ObjCRuntimeHasWeak : 1; // The ARC runtime supports __weak
   unsigned ObjCInferRelatedReturnType : 1; // Infer Objective-C related return
                                            // types
   unsigned FakeAddressSpaceMap : 1; // Use a fake address space map, for
@@ -176,7 +176,8 @@ class LangOptions {
     Trigraphs = BCPLComment = Bool = DollarIdents = AsmPreprocessor = 0;
     GNUMode = GNUKeywords = ImplicitInt = Digraphs = 0;
     HexFloats = 0;
-    ObjCAutoRefCount = ObjCNoAutoRefCountRuntime = 0;
+    ObjCAutoRefCount = 0;
+    ObjCRuntimeHasWeak = 0;
     ObjCInferRelatedReturnType = 0;
     GC = ObjC1 = ObjC2 = ObjCNonFragileABI = ObjCNonFragileABI2 = 0;
     AppleKext = 0;

include/clang/Driver/CC1Options.td

@@ -494,10 +494,12 @@ def fobjc_arc : Flag<"-fobjc-arc">,
   HelpText<"Synthesize retain and release calls for Objective-C pointers">;
 def fobjc_arc_cxxlib_EQ : Joined<"-fobjc-arc-cxxlib=">,
   HelpText<"Objective-C++ Automatic Reference Counting standard library kind">;
-def fobjc_no_arc_runtime : Flag<"-fobjc-no-arc-runtime">,
-  HelpText<"Implement -fobjc-arc without any extra runtime support">;
 def fobjc_arc_exceptions : Flag<"-fobjc-arc-exceptions">,
   HelpText<"Use EH-safe code when synthesizing retains and releases in -fobjc-arc">;
+def fobjc_runtime_has_arc : Flag<"-fobjc-runtime-has-arc">,
+  HelpText<"The target Objective-C runtime provides ARC entrypoints">;
+def fobjc_runtime_has_weak : Flag<"-fobjc-runtime-has-weak">,
+  HelpText<"The target Objective-C runtime supports ARC weak operations">;
 def fobjc_gc : Flag<"-fobjc-gc">,
   HelpText<"Enable Objective-C garbage collection">;
 def fobjc_gc_only : Flag<"-fobjc-gc-only">,

include/clang/Driver/ToolChain.h

@@ -26,6 +26,7 @@ namespace driver {
   class HostInfo;
   class InputArgList;
   class JobAction;
+  class ObjCRuntime;
   class Tool;
 
 /// ToolChain - Access to tools for a single platform.
@@ -166,9 +167,6 @@ class ToolChain {
   /// UseSjLjExceptions - Does this tool chain use SjLj exceptions.
   virtual bool UseSjLjExceptions() const { return false; }
 
-  /// HasARCRuntime - Does this tool chain provide a specialized ARC runtime.
-  virtual bool HasARCRuntime() const { return true; }
-
   /// ComputeLLVMTriple - Return the LLVM target triple to use, after taking
   /// command line arguments into account.
   virtual std::string ComputeLLVMTriple(const ArgList &Args) const;
@@ -180,6 +178,12 @@ class ToolChain {
   /// Clang.
   virtual std::string ComputeEffectiveClangTriple(const ArgList &Args) const;
 
+  /// configureObjCRuntime - Configure the known properties of the
+  /// Objective-C runtime for this platform.
+  ///
+  /// FIXME: this doesn't really belong here.
+  virtual void configureObjCRuntime(ObjCRuntime &runtime) const;
+
   // GetCXXStdlibType - Determine the C++ standard library type to use with the
   // given compilation arguments.
   virtual CXXStdlibType GetCXXStdlibType(const ArgList &Args) const;

include/clang/Frontend/CodeGenOptions.h

@@ -76,6 +76,7 @@ class CodeGenOptions {
   unsigned NoNaNsFPMath      : 1; /// Assume FP arguments, results not NaN.
   unsigned NoZeroInitializedInBSS : 1; /// -fno-zero-initialized-in-bss
   unsigned ObjCDispatchMethod : 2; /// Method of Objective-C dispatch to use.
+  unsigned ObjCRuntimeHasARC : 1; /// The target runtime supports ARC natively
   unsigned OmitLeafFramePointer : 1; /// Set when -momit-leaf-frame-pointer is
                                      /// enabled.
   unsigned OptimizationLevel : 3; /// The -O[0-4] option specified.

lib/ARCMigrate/ARCMT.cpp

@@ -189,7 +189,7 @@ CompilerInvocation *createInvocationForMigration(CompilerInvocation &origCI) {
   CInvok->getDiagnosticOpts().ErrorLimit = 0;
   CInvok->getDiagnosticOpts().Warnings.push_back(
                                             "error=arc-unsafe-retained-assign");
-  CInvok->getLangOpts().ObjCNoAutoRefCountRuntime = !HasARCRuntime(origCI);
+  CInvok->getLangOpts().ObjCRuntimeHasWeak = HasARCRuntime(origCI);
 
   return CInvok.take();
 }

lib/ARCMigrate/TransBlockObjCVariable.cpp

@@ -98,12 +98,12 @@ class RootBlockObjCVarRewriter :
         BlocksAttr *attr = var->getAttr<BlocksAttr>();
         if(!attr)
           continue;
-        bool hasARCRuntime = !Pass.Ctx.getLangOptions().ObjCNoAutoRefCountRuntime;
+        bool hasWeak = Pass.Ctx.getLangOptions().ObjCRuntimeHasWeak;
         SourceManager &SM = Pass.Ctx.getSourceManager();
         Transaction Trans(Pass.TA);
         Pass.TA.replaceText(SM.getInstantiationLoc(attr->getLocation()),
                             "__block",
-                            hasARCRuntime ? "__weak" : "__unsafe_unretained");
+                            hasWeak ? "__weak" : "__unsafe_unretained");
       }
 
     }

lib/ARCMigrate/TransProperties.cpp

@@ -112,7 +112,7 @@ class AssignPropertiesTrans {
   }
 
   void applyWeak(PropData &prop) {
-    assert(!Pass.Ctx.getLangOptions().ObjCNoAutoRefCountRuntime);
+    assert(Pass.Ctx.getLangOptions().ObjCRuntimeHasWeak);
 
     Transaction Trans(Pass.TA);
     Pass.TA.insert(prop.IvarD->getLocation(), "__weak "); 
@@ -157,7 +157,7 @@ class AssignPropertiesTrans {
     // There is a "error: existing ivar for assign property must be
     // __unsafe_unretained"; fix it.
 
-    if (Pass.Ctx.getLangOptions().ObjCNoAutoRefCountRuntime) {
+    if (!Pass.Ctx.getLangOptions().ObjCRuntimeHasWeak) {
       // We will just add __unsafe_unretained to the ivar.
       Transaction Trans(Pass.TA);
       Pass.TA.insert(ivarD->getLocation(), "__unsafe_unretained ");

lib/CodeGen/CGObjC.cpp

@@ -1311,7 +1311,7 @@ static llvm::Constant *createARCRuntimeFunction(CodeGenModule &CGM,
 
   // In -fobjc-no-arc-runtime, emit weak references to the runtime
   // support library.
-  if (CGM.getLangOptions().ObjCNoAutoRefCountRuntime)
+  if (!CGM.getCodeGenOpts().ObjCRuntimeHasARC)
     if (llvm::Function *f = dyn_cast<llvm::Function>(fn))
       f->setLinkage(llvm::Function::ExternalWeakLinkage);
 
@@ -2457,13 +2457,7 @@ void CodeGenFunction::EmitObjCAutoreleasePoolStmt(
 
   // Keep track of the current cleanup stack depth.
   RunCleanupsScope Scope(*this);
-  const llvm::Triple Triple = getContext().Target.getTriple();
-  if (CGM.getLangOptions().ObjCAutoRefCount ||
-      (CGM.isTargetDarwin() && 
-       ((Triple.getArch() == llvm::Triple::x86_64 && 
-         !Triple.isMacOSXVersionLT(10,7,0))
-        || (Triple.getEnvironmentName() == "iphoneos" && 
-            !Triple.isOSVersionLT(5,0))))) {
+  if (CGM.getCodeGenOpts().ObjCRuntimeHasARC) {
     llvm::Value *token = EmitObjCAutoreleasePoolPush();
     EHStack.pushCleanup<CallObjCAutoreleasePoolObject>(NormalCleanup, token);
   } else {

lib/Driver/Compilation.cpp

@@ -13,6 +13,7 @@
 #include "clang/Driver/ArgList.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/ObjCRuntime.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/ToolChain.h"
 

lib/Driver/ToolChain.cpp

@@ -15,7 +15,9 @@
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/HostInfo.h"
+#include "clang/Driver/ObjCRuntime.h"
 #include "clang/Driver/Options.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace clang::driver;
 
@@ -47,6 +49,23 @@ bool ToolChain::HasNativeLLVMSupport() const {
   return false;
 }
 
+void ToolChain::configureObjCRuntime(ObjCRuntime &runtime) const {
+  switch (runtime.getKind()) {
+  case ObjCRuntime::NeXT:
+    // Assume a minimal NeXT runtime.
+    runtime.HasARC = false;
+    runtime.HasWeak = false;
+    return;
+
+  case ObjCRuntime::GNU:
+    // Assume a maximal GNU runtime.
+    runtime.HasARC = true;
+    runtime.HasWeak = true;
+    return;
+  }
+  llvm_unreachable("invalid runtime kind!");
+}
+
 /// getARMTargetCPU - Get the (LLVM) name of the ARM cpu we are targeting.
 //
 // FIXME: tblgen this.

lib/Driver/ToolChains.cpp

@@ -19,6 +19,7 @@
 #include "clang/Driver/Driver.h"
 #include "clang/Driver/DriverDiagnostic.h"
 #include "clang/Driver/HostInfo.h"
+#include "clang/Driver/ObjCRuntime.h"
 #include "clang/Driver/OptTable.h"
 #include "clang/Driver/Option.h"
 #include "clang/Driver/Options.h"
@@ -74,8 +75,7 @@ bool Darwin::HasNativeLLVMSupport() const {
   return true;
 }
 
-/// Darwin provides an ARC runtime starting in MacOS X 10.7 and iOS 5.0.
-bool Darwin::HasARCRuntime() const {
+bool Darwin::hasARCRuntime() const {
   // FIXME: Remove this once there is a proper way to detect an ARC runtime
   // for the simulator.
   switch (ARCRuntimeForSimulator) {
@@ -93,6 +93,14 @@ bool Darwin::HasARCRuntime() const {
     return !isMacosxVersionLT(10, 7);
 }
 
+/// Darwin provides an ARC runtime starting in MacOS X 10.7 and iOS 5.0.
+void Darwin::configureObjCRuntime(ObjCRuntime &runtime) const {
+  if (runtime.getKind() != ObjCRuntime::NeXT)
+    return ToolChain::configureObjCRuntime(runtime);
+
+  runtime.HasARC = runtime.HasWeak = hasARCRuntime();
+}
+
 // FIXME: Can we tablegen this?
 static const char *GetArmArchForMArch(llvm::StringRef Value) {
   if (Value == "armv6k")

lib/Driver/ToolChains.h

@@ -80,6 +80,8 @@ class LLVM_LIBRARY_VISIBILITY Darwin : public ToolChain {
   /// initialized.
   std::string MacosxVersionMin;
 
+  bool hasARCRuntime() const;
+
 private:
   void AddDeploymentTarget(DerivedArgList &Args) const;
 
@@ -184,7 +186,7 @@ class LLVM_LIBRARY_VISIBILITY Darwin : public ToolChain {
 
   virtual bool HasNativeLLVMSupport() const;
 
-  virtual bool HasARCRuntime() const;
+  virtual void configureObjCRuntime(ObjCRuntime &runtime) const;
 
   virtual DerivedArgList *TranslateArgs(const DerivedArgList &Args,
                                         const char *BoundArch) const;

lib/Driver/Tools.cpp

@@ -17,6 +17,7 @@
 #include "clang/Driver/Compilation.h"
 #include "clang/Driver/Job.h"
 #include "clang/Driver/HostInfo.h"
+#include "clang/Driver/ObjCRuntime.h"
 #include "clang/Driver/Option.h"
 #include "clang/Driver/Options.h"
 #include "clang/Driver/ToolChain.h"
@@ -1600,47 +1601,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                     options::OPT_fno_lax_vector_conversions))
     CmdArgs.push_back("-fno-lax-vector-conversions");
 
-  // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
-  // NOTE: This logic is duplicated in ToolChains.cpp.
-  bool ARC = isObjCAutoRefCount(Args);
-  if (ARC) {
-    CmdArgs.push_back("-fobjc-arc");
-
-    // Certain deployment targets don't have runtime support.
-    if (!getToolChain().HasARCRuntime())
-      CmdArgs.push_back("-fobjc-no-arc-runtime");
-
-    // Allow the user to enable full exceptions code emission.
-    // We define off for Objective-CC, on for Objective-C++.
-    if (Args.hasFlag(options::OPT_fobjc_arc_exceptions,
-                     options::OPT_fno_objc_arc_exceptions,
-                     /*default*/ types::isCXX(InputType)))
-      CmdArgs.push_back("-fobjc-arc-exceptions");
-  }
-
-  // -fobjc-infer-related-result-type is the default, except in the Objective-C
-  // rewriter.
-  if (IsRewriter)
-    CmdArgs.push_back("-fno-objc-infer-related-result-type");
-  
-  // Handle -fobjc-gc and -fobjc-gc-only. They are exclusive, and -fobjc-gc-only
-  // takes precedence.
-  const Arg *GCArg = Args.getLastArg(options::OPT_fobjc_gc_only);
-  if (!GCArg)
-    GCArg = Args.getLastArg(options::OPT_fobjc_gc);
-  if (GCArg) {
-    if (ARC) {
-      D.Diag(clang::diag::err_drv_objc_gc_arr)
-        << GCArg->getAsString(Args);
-    } else if (getToolChain().SupportsObjCGC()) {
-      GCArg->render(Args, CmdArgs);
-    } else {
-      // FIXME: We should move this to a hard error.
-      D.Diag(clang::diag::warn_drv_objc_gc_unsupported)
-        << GCArg->getAsString(Args);
-    }
-  }
-
   if (Args.getLastArg(options::OPT_fapple_kext))
     CmdArgs.push_back("-fapple-kext");
 
@@ -1805,17 +1765,23 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                    false))
     CmdArgs.push_back("-fgnu89-inline");
 
-  // -fnext-runtime defaults to on Darwin and when rewriting Objective-C, and is
-  // -the -cc1 default.
-  bool NeXTRuntimeIsDefault =
-    IsRewriter || getToolChain().getTriple().getOS() == llvm::Triple::Darwin;
-  if (!Args.hasFlag(options::OPT_fnext_runtime, options::OPT_fgnu_runtime,
-                    NeXTRuntimeIsDefault))
-    CmdArgs.push_back("-fgnu-runtime");
-
   // -fobjc-nonfragile-abi=0 is default.
+  ObjCRuntime objCRuntime;
   unsigned objcABIVersion = 0;
   if (types::isObjC(InputType)) {
+    bool NeXTRuntimeIsDefault
+      = (IsRewriter || getToolChain().getTriple().isOSDarwin());
+    if (Args.hasFlag(options::OPT_fnext_runtime, options::OPT_fgnu_runtime,
+                     NeXTRuntimeIsDefault))
+      objCRuntime.setKind(ObjCRuntime::NeXT);
+    else
+      objCRuntime.setKind(ObjCRuntime::GNU);
+    getToolChain().configureObjCRuntime(objCRuntime);
+    if (objCRuntime.HasARC)
+      CmdArgs.push_back("-fobjc-runtime-has-arc");
+    if (objCRuntime.HasWeak)
+      CmdArgs.push_back("-fobjc-runtime-has-weak");
+
     // Compute the Objective-C ABI "version" to use. Version numbers are
     // slightly confusing for historical reasons:
     //   1 - Traditional "fragile" ABI
@@ -1890,6 +1856,43 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 #endif
   }
 
+  // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
+  // NOTE: This logic is duplicated in ToolChains.cpp.
+  bool ARC = isObjCAutoRefCount(Args);
+  if (ARC) {
+    CmdArgs.push_back("-fobjc-arc");
+
+    // Allow the user to enable full exceptions code emission.
+    // We define off for Objective-CC, on for Objective-C++.
+    if (Args.hasFlag(options::OPT_fobjc_arc_exceptions,
+                     options::OPT_fno_objc_arc_exceptions,
+                     /*default*/ types::isCXX(InputType)))
+      CmdArgs.push_back("-fobjc-arc-exceptions");
+  }
+
+  // -fobjc-infer-related-result-type is the default, except in the Objective-C
+  // rewriter.
+  if (IsRewriter)
+    CmdArgs.push_back("-fno-objc-infer-related-result-type");
+  
+  // Handle -fobjc-gc and -fobjc-gc-only. They are exclusive, and -fobjc-gc-only
+  // takes precedence.
+  const Arg *GCArg = Args.getLastArg(options::OPT_fobjc_gc_only);
+  if (!GCArg)
+    GCArg = Args.getLastArg(options::OPT_fobjc_gc);
+  if (GCArg) {
+    if (ARC) {
+      D.Diag(clang::diag::err_drv_objc_gc_arr)
+        << GCArg->getAsString(Args);
+    } else if (getToolChain().SupportsObjCGC()) {
+      GCArg->render(Args, CmdArgs);
+    } else {
+      // FIXME: We should move this to a hard error.
+      D.Diag(clang::diag::warn_drv_objc_gc_unsupported)
+        << GCArg->getAsString(Args);
+    }
+  }
+
   // Add exception args.
   addExceptionArgs(Args, InputType, getToolChain().getTriple(),
                    KernelOrKext, IsRewriter, objcABIVersion, CmdArgs);
@@ -3237,8 +3240,12 @@ void darwin::Link::ConstructJob(Compilation &C, const JobAction &JA,
   // In ARC, if we don't have runtime support, link in the runtime
   // stubs.  We have to do this *before* adding any of the normal
   // linker inputs so that its initializer gets run first.
-  if (!getDarwinToolChain().HasARCRuntime() && isObjCAutoRefCount(Args))
-    getDarwinToolChain().AddLinkARCArgs(Args, CmdArgs);
+  if (isObjCAutoRefCount(Args)) {
+    ObjCRuntime runtime;
+    getDarwinToolChain().configureObjCRuntime(runtime);
+    if (!runtime.HasARC)
+      getDarwinToolChain().AddLinkARCArgs(Args, CmdArgs);
+  }
 
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);