release/21.x [ObjCARC] Delete empty autoreleasepools with no autoreleases in them and remove ObjCARCAPElimPass

clang/lib/CodeGen/BackendUtil.cpp

@@ -1027,12 +1027,6 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
               MPM.addPass(
                   createModuleToFunctionPassAdaptor(ObjCARCExpandPass()));
           });
-      PB.registerPipelineEarlySimplificationEPCallback(
-          [](ModulePassManager &MPM, OptimizationLevel Level,
-             ThinOrFullLTOPhase) {
-            if (Level != OptimizationLevel::O0)
-              MPM.addPass(ObjCARCAPElimPass());
-          });
       PB.registerScalarOptimizerLateEPCallback(
           [](FunctionPassManager &FPM, OptimizationLevel Level) {
             if (Level != OptimizationLevel::O0)

llvm/include/llvm/Transforms/ObjCARC.h

@@ -35,10 +35,6 @@ struct ObjCARCContractPass : public PassInfoMixin<ObjCARCContractPass> {
   LLVM_ABI PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 };
 
-struct ObjCARCAPElimPass : public PassInfoMixin<ObjCARCAPElimPass> {
-  LLVM_ABI PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
-};
-
 struct ObjCARCExpandPass : public PassInfoMixin<ObjCARCExpandPass> {
   LLVM_ABI PreservedAnalyses run(Function &M, FunctionAnalysisManager &AM);
 };

llvm/lib/Passes/PassRegistry.def

@@ -119,7 +119,6 @@ MODULE_PASS("module-inline", ModuleInlinerPass())
 MODULE_PASS("name-anon-globals", NameAnonGlobalPass())
 MODULE_PASS("no-op-module", NoOpModulePass())
 MODULE_PASS("nsan", NumericalStabilitySanitizerPass())
-MODULE_PASS("objc-arc-apelim", ObjCARCAPElimPass())
 MODULE_PASS("openmp-opt", OpenMPOptPass())
 MODULE_PASS("openmp-opt-postlink",
             OpenMPOptPass(ThinOrFullLTOPhase::FullLTOPostLink))

llvm/lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h

@@ -46,6 +46,8 @@ enum class ARCRuntimeEntryPointKind {
   UnsafeClaimRV,
   RetainAutorelease,
   RetainAutoreleaseRV,
+  AutoreleasePoolPush,
+  AutoreleasePoolPop,
 };
 
 /// Declarations for ObjC runtime functions and constants. These are initialized
@@ -67,6 +69,8 @@ class ARCRuntimeEntryPoints {
     UnsafeClaimRV = nullptr;
     RetainAutorelease = nullptr;
     RetainAutoreleaseRV = nullptr;
+    AutoreleasePoolPush = nullptr;
+    AutoreleasePoolPop = nullptr;
   }
 
   Function *get(ARCRuntimeEntryPointKind kind) {
@@ -101,6 +105,12 @@ class ARCRuntimeEntryPoints {
     case ARCRuntimeEntryPointKind::RetainAutoreleaseRV:
       return getIntrinsicEntryPoint(RetainAutoreleaseRV,
                                 Intrinsic::objc_retainAutoreleaseReturnValue);
+    case ARCRuntimeEntryPointKind::AutoreleasePoolPush:
+      return getIntrinsicEntryPoint(AutoreleasePoolPush,
+                                    Intrinsic::objc_autoreleasePoolPush);
+    case ARCRuntimeEntryPointKind::AutoreleasePoolPop:
+      return getIntrinsicEntryPoint(AutoreleasePoolPop,
+                                    Intrinsic::objc_autoreleasePoolPop);
     }
 
     llvm_unreachable("Switch should be a covered switch.");
@@ -143,6 +153,12 @@ class ARCRuntimeEntryPoints {
   /// Declaration for objc_retainAutoreleaseReturnValue().
   Function *RetainAutoreleaseRV = nullptr;
 
+  /// Declaration for objc_autoreleasePoolPush().
+  Function *AutoreleasePoolPush = nullptr;
+
+  /// Declaration for objc_autoreleasePoolPop().
+  Function *AutoreleasePoolPop = nullptr;
+
   Function *getIntrinsicEntryPoint(Function *&Decl, Intrinsic::ID IntID) {
     if (Decl)
       return Decl;

llvm/lib/Transforms/ObjCARC/CMakeLists.txt

@@ -2,7 +2,6 @@ add_llvm_component_library(LLVMObjCARCOpts
   ObjCARC.cpp
   ObjCARCOpts.cpp
   ObjCARCExpand.cpp
-  ObjCARCAPElim.cpp
   ObjCARCContract.cpp
   DependencyAnalysis.cpp
   ProvenanceAnalysis.cpp