[K/N] Add ObjCARCContract LLVM pass.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/OptimizationPipeline.kt

@@ -22,6 +22,7 @@ private fun initializeLlvmGlobalPassRegistry() {
     LLVMInitializeIPA(passRegistry)
     LLVMInitializeCodeGen(passRegistry)
     LLVMInitializeTarget(passRegistry)
+    LLVMInitializeObjCARCOpts(passRegistry)
 }
 
 internal fun shouldRunLateBitcodePasses(context: Context): Boolean {
@@ -166,10 +167,16 @@ internal fun runLlvmOptimizationPipeline(context: Context) {
         config.customInlineThreshold?.let { threshold ->
             LLVMPassManagerBuilderUseInlinerWithThreshold(passBuilder, threshold)
         }
+
         // Pipeline that is similar to `llvm-lto`.
-        // TODO: Add ObjC optimization passes.
         LLVMPassManagerBuilderPopulateLTOPassManager(passBuilder, modulePasses, Internalize = 0, RunInliner = 1)
 
+        // Lower ObjC ARC intrinsics (e.g. `@llvm.objc.clang.arc.use(...)`).
+        // While Kotlin/Native codegen itself doesn't produce these intrinsics, they might come
+        // from cinterop "glue" bitcode.
+        // TODO: Consider adding other ObjC passes.
+        LLVMAddObjCARCContractPass(modulePasses)
+
         LLVMRunPassManager(modulePasses, llvmModule)
 
         LLVMPassManagerBuilderDispose(passBuilder)

kotlin-native/llvmCoverageMappingC/src/main/cpp/CoverageMappingC.cpp

@@ -19,8 +19,10 @@
 #include <llvm/IR/LegacyPassManager.h>
 #include <llvm/Analysis/TargetLibraryInfo.h>
 #include <llvm/Transforms/Instrumentation.h>
+#include <llvm/Transforms/ObjCARC.h>
 #include <llvm/Support/FileSystem.h>
 #include <llvm/Support/Path.h>
+
 #include <utility>
 #include <string>
 #include <vector>
@@ -230,6 +232,11 @@ void LLVMKotlinAddTargetLibraryInfoWrapperPass(LLVMPassManagerRef passManagerRef
   passManager->add(new TargetLibraryInfoWrapperPass(Triple(targetTriple)));
 }
 
+void LLVMAddObjCARCContractPass(LLVMPassManagerRef passManagerRef) {
+    legacy::PassManagerBase *passManager = unwrap(passManagerRef);
+    passManager->add(createObjCARCContractPass());
+}
+
 void LLVMKotlinInitializeTargets() {
 #define INIT_LLVM_TARGET(TargetName) \
     LLVMInitialize##TargetName##TargetInfo();\

kotlin-native/llvmCoverageMappingC/src/main/include/CoverageMappingC.h

@@ -74,6 +74,8 @@ void LLVMAddInstrProfPass(LLVMPassManagerRef passManagerRef, const char* outputF
 
 void LLVMKotlinAddTargetLibraryInfoWrapperPass(LLVMPassManagerRef passManagerRef, const char* targetTriple);
 
+void LLVMAddObjCARCContractPass(LLVMPassManagerRef passManagerRef);
+
 void LLVMKotlinInitializeTargets();
 
 # ifdef __cplusplus