[PATCH] D55233: Add objc_retain and objc_release intrinsics and codegen them to their runtime methods

[Pete Cooper via Phabricator via llvm-commits]

pete created this revision.
pete added reviewers: erik.pilkington, ahatanak.
Herald added a subscriber: llvm-commits.

This is the first in a series of patches to move objc retain/release to intrinsics and have the ARC optimizer work on those instead.

For some context, see clang r263607 which converted [a retain] to objc_retain(a).  That was ultimately reverted as the ARC optimizer couldn't handle the new calls.

The eventual solution is to move the ARC inserted retain/release calls to intrinsics and only optimize the intrinsics.  Manually inserted retain/release will then no longer be optimized.


Repository:
  rL LLVM

https://reviews.llvm.org/D55233

Files:
  include/llvm/IR/Intrinsics.td
  lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
  test/CodeGen/X86/objc-arc.ll


Index: test/CodeGen/X86/objc-arc.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/objc-arc.ll
@@ -0,0 +1,22 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+
+; Make sure calls to the objc intrinsics are translated to calls in to the runtime
+
+define i8* @test1(i8* %arg) {
+; CHECK-LABEL: test1
+; CHECK: callq _objc_retain
+entry:
+	%0 = call i8* @llvm.objc.retain(i8* %arg)
+	ret i8* %0
+}
+
+define void @test2(i8* %arg) {
+; CHECK-LABEL: test2
+; CHECK: callq _objc_release
+entry:
+	call void @llvm.objc.release(i8* %arg)
+	ret void
+}
+
+declare i8* @llvm.objc.retain(i8*)
+declare void @llvm.objc.release(i8* %arg)
Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6337,6 +6337,10 @@
     // MachineFunction in SelectionDAGISel::PrepareEHLandingPad. We can safely
     // delete it now.
     return nullptr;
+  case Intrinsic::objc_retain:
+    return "objc_retain";
+  case Intrinsic::objc_release:
+    return "objc_release";
   }
 }
 
Index: include/llvm/IR/Intrinsics.td
===================================================================
--- include/llvm/IR/Intrinsics.td
+++ include/llvm/IR/Intrinsics.td
@@ -319,6 +319,11 @@
                             [llvm_ptr_ty, llvm_ptr_ty, llvm_ptrptr_ty],
                             [IntrArgMemOnly, NoCapture<1>, NoCapture<2>]>;
 
+//===------------------- ObjC ARC runtime Intrinsics --------------------===//
+//
+def int_objc_retain  : Intrinsic<[llvm_ptr_ty], [llvm_ptr_ty], [Returned<0>]>;
+def int_objc_release  : Intrinsic<[], [llvm_ptr_ty]>;
+
 //===--------------------- Code Generator Intrinsics ----------------------===//
 //
 def int_returnaddress : Intrinsic<[llvm_ptr_ty], [llvm_i32_ty], [IntrNoMem]>;


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