[PATCH] D66121: Debug Info: Nest Objective-C property function decls inside their container.

[Adrian Prantl via Phabricator via cfe-commits]

aprantl added a comment.

In D66121#1656442 <https://reviews.llvm.org/D66121#1656442>, @rjmccall wrote:

> Can you prepare an NFC patch with just the changes relating to adding `ObjCPropertyImplDecl::get{Getter,Setter}MethodDecl`?


Sure, I will do that.

> I don't get why the redeclaration logic is changing.  What happens when a normal method is implemented?  Is that not linked up as a redeclaration?

>From what I can tell from injecting an assertion into `ObjCMethodDecl::setAsRedeclaration()` only redeclarations within the same protocol/interface/category are linked up as redeclarations. An implementation of an interface is not a redeclaration in the SemaObjC sense. Digging further, this is implemented in https://github.com/llvm/llvm-project/blob/244e738485445fa4b72bfef9b9b2f9625cee989e/clang/lib/Sema/SemaDeclObjC.cpp#L3930 by checking whether a method's selector has been processed before within the same property/interface/category.

That's very different from what my patch is doing. The following example is extracted from `clang/test/CodeGenObjC/newproperty-nested-synthesis-1.m`:

   1	@interface Tester : Object
   2	@property char PropertyAtomic_char;
   3	@end
   4	
   5	@implementation Tester
   6	@dynamic PropertyAtomic_char;
   7	@end
   8	
   9	@interface SubClass : Tester
  10	{
  11	    char PropertyAtomic_char;
  12	}
  13	@end
  14	
  15	@implementation SubClass
  16	@synthesize PropertyAtomic_char;
  17	@end

My patch sets the getter synthesized at line 6 up as a redeclaration of getter from the interface on line 2 and the getter from `SubClass` on line 16 as a redeclaration of the getter from `Tester` on line 6. That must be wrong: If there were another subclass of `Tester` with another getter, the compiler would assert, because each Objective-C method declaration can have at most one redeclaration.

So in summary I think what I was trying to do doesn't make sense in the existing infrastructure and I shouldn't be trying to set up methods as redeclarations between *different* interfaces/protocols/implementations. Do you agree with this assessment? If yes I'll try to redo the patch without using the redeclaration mechanism.


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