Driver: remove `SupportsObjCGC`

[compnerd]

Summary

This option is not used in the frontend. Remove the method.

[compnerd]

@rjmccall this is quite a straightforward change, just not sure if there is some use for this that I cant think of off the top of my head to preserve this.

[rjmccall]

This isn't changing the actual driver interface in any way, it's just dead-code removal. Seems fine to me.

[compnerd]

SVN r318609

include/clang/Driver/ToolChain.h

   /// SupportsProfiling - Does this tool chain support -pg.
   virtual bool SupportsProfiling() const { return true; }
 
-  /// Does this tool chain support Objective-C garbage collection.
-  virtual bool SupportsObjCGC() const { return true; }
-
   /// Complain if this tool chain doesn't support Objective-C ARC.
   virtual void CheckObjCARC() const {}
 

lib/Driver/ToolChains/BareMetal.h

   bool isPIEDefault() const override { return false; }
   bool isPICDefaultForced() const override { return false; }
   bool SupportsProfiling() const override { return false; }
-  bool SupportsObjCGC() const override { return false; }
 
   RuntimeLibType GetDefaultRuntimeLibType() const override {
     return ToolChain::RLT_CompilerRT;

lib/Driver/ToolChains/Cuda.h

   bool isPIEDefault() const override { return false; }
   bool isPICDefaultForced() const override { return false; }
   bool SupportsProfiling() const override { return false; }
-  bool SupportsObjCGC() const override { return false; }
   bool IsMathErrnoDefault() const override { return false; }
 
   void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,

lib/Driver/ToolChains/Darwin.h

 
   bool SupportsProfiling() const override;
 
-  bool SupportsObjCGC() const override { return false; }
-
   bool UseDwarfDebugFlags() const override;
 
   bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override {

     return 0;
   }
 
-  bool SupportsObjCGC() const override;
-
   void CheckObjCARC() const override;
 
   bool UseSjLjExceptions(const llvm::opt::ArgList &Args) const override;

lib/Driver/ToolChains/Darwin.cpp

   }
 }
 
-bool Darwin::SupportsObjCGC() const { return isTargetMacOS(); }
-
 void Darwin::CheckObjCARC() const {
   if (isTargetIOSBased() || isTargetWatchOSBased() ||
       (isTargetMacOS() && !isMacosxVersionLT(10, 6)))

lib/Driver/ToolChains/WebAssembly.h

   bool isPICDefaultForced() const override;
   bool IsIntegratedAssemblerDefault() const override;
   bool hasBlocksRuntime() const override;
-  bool SupportsObjCGC() const override;
   bool SupportsProfiling() const override;
   bool HasNativeLLVMSupport() const override;
   void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,

lib/Driver/ToolChains/WebAssembly.cpp

 
 bool WebAssembly::IsIntegratedAssemblerDefault() const { return true; }
 
-// TODO: Support Objective C stuff.
-bool WebAssembly::SupportsObjCGC() const { return false; }
-
 bool WebAssembly::hasBlocksRuntime() const { return false; }
 
 // TODO: Support profiling.