[PATCH] D57936: [CodeGenObjC] When available, emit a direct call to objc_alloc_init(cls) instead of [objc_alloc(cls) init]

[Greg Parker via Phabricator via cfe-commits]

gparker42 added inline comments.


================
Comment at: clang/lib/CodeGen/CGObjC.cpp:459
+  llvm::Value *Receiver =
+      CGF.CGM.getObjCRuntime().GetClass(CGF, ObjTy->getInterface());
+  return CGF.EmitObjCAllocInit(Receiver, CGF.ConvertType(OME->getType()));
----------------
rjmccall wrote:
> You might need to check for a `super` message send, which can be a class message send in a class method.
> 
> Also, I think `getInterface()` can return null here, although it might need to be contrived to fit the other requirements.  `Class<SomeProtocol>`, where that protocol declares `+alloc`?  If there isn't a way to just emit the receiver pointer of a normal message send from an `ObjCMessageExpr`, that's really too bad.
Should this be done inside `tryGenerateSpecializedMessageSend`, or from the same place that calls `tryGenerateSpecializedMessageSend`? That position already rejects `[super …]` call sites, and might make it more obvious how the `objc_alloc` and `objc_alloc_init` optimizations interact. (Currently it takes some digging to verify that the `objc_alloc_init` generator does not need to look for the pattern `[objc_alloc(cls) init]`).


Repository:
  rC Clang

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  https://reviews.llvm.org/D57936/new/

https://reviews.llvm.org/D57936