backend: generate refs cleanup code for exceptional unwind

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/CodeGenerator.kt

@@ -42,6 +42,7 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
         prologueBb = LLVMAppendBasicBlock(function, "prologue")
         entryBb = LLVMAppendBasicBlock(function, "entry")
         epilogueBb = LLVMAppendBasicBlock(function, "epilogue")
+        cleanupLandingpad = LLVMAppendBasicBlock(function, "cleanup_landingpad")!!
         positionAtEnd(entryBb!!)
         slotsPhi = phi(kObjHeaderPtrPtr)
         slotCount = 0
@@ -88,6 +89,13 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
             }
         }
 
+        appendingTo(cleanupLandingpad!!) {
+            val landingpad = gxxLandingpad(numClauses = 0)
+            LLVMSetCleanup(landingpad, 1)
+            releaseVars()
+            LLVMBuildResume(builder, landingpad)
+        }
+
         returns.clear()
         vars.clear()
         returnSlot = null
@@ -104,6 +112,7 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
     private var prologueBb: LLVMBasicBlockRef? = null
     private var entryBb: LLVMBasicBlockRef? = null
     private var epilogueBb: LLVMBasicBlockRef? = null
+    private var cleanupLandingpad: LLVMBasicBlockRef? = null
 
     fun setName(value: LLVMValueRef, name: String) = LLVMSetValueName(value, name)
 
@@ -302,6 +311,17 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
 
     //-------------------------------------------------------------------------//
 
+    fun gxxLandingpad(numClauses: Int, name: String = ""): LLVMValueRef {
+        val personalityFunction = LLVMConstBitCast(context.llvm.gxxPersonalityFunction, int8TypePtr)
+
+        // Type of `landingpad` instruction result (depends on personality function):
+        val landingpadType = structType(int8TypePtr, int32Type)
+
+        return LLVMBuildLandingPad(builder, landingpadType, personalityFunction, numClauses, name)!!
+    }
+
+    //-------------------------------------------------------------------------//
+
     /**
      * Represents the mutable position of instructions being inserted.
      *

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/ContextUtils.kt

@@ -220,6 +220,22 @@ internal class Llvm(val context: Context, val llvmModule: LLVMModuleRef) {
         }
     }
 
+    private fun externalFunction(name: String, type: LLVMTypeRef): LLVMValueRef {
+        val found = LLVMGetNamedFunction(context.llvmModule, name)
+        if (found != null) {
+            assert (getFunctionType(found) == type)
+            return found
+        } else {
+            return LLVMAddFunction(context.llvmModule, name, type)!!
+        }
+    }
+
+    private fun externalNounwindFunction(name: String, type: LLVMTypeRef): LLVMValueRef {
+        val function = externalFunction(name, type)
+        LLVMAddFunctionAttr(function, LLVMAttribute.LLVMNoUnwindAttribute)
+        return function
+    }
+
     val staticData = StaticData(context)
 
     val runtimeFile = context.config.configuration.get(KonanConfigKeys.RUNTIME_FILE)!!
@@ -250,7 +266,13 @@ internal class Llvm(val context: Context, val llvmModule: LLVMModuleRef) {
     val checkInstanceFunction = importRtFunction("CheckInstance")
     val throwExceptionFunction = importRtFunction("ThrowException")
     val appendToInitalizersTail = importRtFunction("AppendToInitializersTail")
+
+    val gxxPersonalityFunction = externalNounwindFunction("__gxx_personality_v0", functionType(int32Type, true))
+    val cxaBeginCatchFunction = externalNounwindFunction("__cxa_begin_catch", functionType(int8TypePtr, false, int8TypePtr))
+    val cxaEndCatchFunction = externalNounwindFunction("__cxa_end_catch", functionType(voidType, false))
+
     val memsetFunction = importMemset()
+
     val usedFunctions = mutableListOf<LLVMValueRef>()
     val staticInitializers = mutableListOf<LLVMValueRef>()
     val fileInitializers = mutableListOf<IrElement>()

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/IrToBitcode.kt

@@ -913,15 +913,7 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
          */
         private fun genLandingpad() {
             with(codegen) {
-                // Type of `landingpad` instruction result (depends on personality function):
-                val landingpadType = structType(int8TypePtr, int32Type)
-
-                val personalityFunction = externalFunction("__gxx_personality_v0", functionType(int32Type, true))
-                val personalityFunctionRaw = LLVMConstBitCast(personalityFunction, int8TypePtr)!!
-
-                val numClauses = 1
-                val landingpadResult =
-                        LLVMBuildLandingPad(codegen.builder, landingpadType, personalityFunctionRaw, numClauses, "lp")
+                val landingpadResult = codegen.gxxLandingpad(numClauses = 1, name = "lp")
 
                 LLVMAddClause(landingpadResult, LLVMConstNull(kInt8Ptr))
 
@@ -931,7 +923,7 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
                 val exceptionRecord = LLVMBuildExtractValue(codegen.builder, landingpadResult, 0, "er")
 
                 // __cxa_begin_catch returns pointer to C++ exception object.
-                val beginCatch = externalFunction("__cxa_begin_catch", functionType(int8TypePtr, false, int8TypePtr))
+                val beginCatch = context.llvm.cxaBeginCatchFunction
                 val exceptionRawPtr = call(beginCatch, listOf(exceptionRecord), "")
 
                 // Pointer to KotlinException instance:
@@ -942,7 +934,7 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
                 val exceptionPtr = loadSlot(exceptionPtrPtr, true, "exception")
 
                 // __cxa_end_catch performs some C++ cleanup, including calling `KotlinException` class destructor.
-                val endCatch = externalFunction("__cxa_end_catch", functionType(voidType, false))
+                val endCatch = context.llvm.cxaEndCatchFunction
                 call(endCatch, listOf(), "")
 
                 jumpToHandler(exceptionPtr)

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/LlvmUtils.kt

@@ -193,16 +193,6 @@ internal fun getGlobalType(ptrToGlobal: LLVMValueRef): LLVMTypeRef {
     return LLVMGetElementType(ptrToGlobal.type)!!
 }
 
-internal fun ContextUtils.externalFunction(name: String, type: LLVMTypeRef): LLVMValueRef {
-    val found = LLVMGetNamedFunction(context.llvmModule, name)
-    if (found != null) {
-        assert (getFunctionType(found) == type)
-        return found
-    } else {
-        return LLVMAddFunction(context.llvmModule, name, type)!!
-    }
-}
-
 internal fun ContextUtils.externalGlobal(name: String, type: LLVMTypeRef): LLVMValueRef {
     val found = LLVMGetNamedGlobal(context.llvmModule, name)
     if (found != null) {