Apply minor refactoring to exception handling

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

@@ -180,7 +180,7 @@ private class ExportedElement(val kind: ElementKind,
                         val numParams = LLVMCountParams(llvmFunction)
                         val args = (0 .. numParams - 1).map { index -> param(index) }
                         val callee = lookupVirtualImpl(receiver, function)
-                        val result = callAtFunctionScopeVerbatim(callee, args)
+                        val result = call(callee, args, exceptionHandler = ExceptionHandler.Caller, verbatim = true)
                         ret(result)
                     }
 

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

@@ -51,6 +51,14 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
     fun functionHash(descriptor: FunctionDescriptor): LLVMValueRef = descriptor.functionName.localHash.llvm
 }
 
+internal sealed class ExceptionHandler {
+    object None : ExceptionHandler()
+    object Caller : ExceptionHandler()
+    abstract class Local : ExceptionHandler() {
+        abstract val unwind: LLVMBasicBlockRef
+    }
+}
+
 val LLVMValueRef.name:String?
     get() = LLVMGetValueName(this)?.toKString()
 
@@ -132,6 +140,9 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
     private val epilogueBb        = basicBlockInFunction("epilogue", endLocation)
     private val cleanupLandingpad = basicBlockInFunction("cleanup_landingpad", endLocation)
 
+    /**
+     * TODO: consider merging this with [ExceptionHandler].
+     */
     var forwardingForeignExceptionsTerminatedWith: LLVMValueRef? = null
 
     init {
@@ -241,17 +252,9 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
 
     //-------------------------------------------------------------------------//
 
-    fun callAtFunctionScope(llvmFunction: LLVMValueRef, args: List<LLVMValueRef>,
-                            lifetime: Lifetime) =
-            call(llvmFunction, args, lifetime, { cleanupLandingpad })
-
-
-    fun callAtFunctionScopeVerbatim(llvmFunction: LLVMValueRef, args: List<LLVMValueRef>) =
-            call(llvmFunction, args, Lifetime.IRRELEVANT, { cleanupLandingpad }, true)
-
     fun call(llvmFunction: LLVMValueRef, args: List<LLVMValueRef>,
              resultLifetime: Lifetime = Lifetime.IRRELEVANT,
-             lazyLandingpad: () -> LLVMBasicBlockRef? = { null },
+             exceptionHandler: ExceptionHandler = ExceptionHandler.None,
              verbatim: Boolean = false): LLVMValueRef {
         val callArgs = if (verbatim || !isObjectReturn(llvmFunction.type)) {
             args
@@ -291,30 +294,34 @@ internal class FunctionGenerationContext(val function: LLVMValueRef,
             }
             args + resultSlot
         }
-        return callRaw(llvmFunction, callArgs, lazyLandingpad)
+        return callRaw(llvmFunction, callArgs, exceptionHandler)
     }
 
     private fun callRaw(llvmFunction: LLVMValueRef, args: List<LLVMValueRef>,
-                        lazyLandingpad: () -> LLVMBasicBlockRef?): LLVMValueRef {
+                        exceptionHandler: ExceptionHandler): LLVMValueRef {
         val rargs = args.toCValues()
         if (LLVMIsAFunction(llvmFunction) != null /* the function declaration */  &&
                 isFunctionNoUnwind(llvmFunction)) {
 
             return LLVMBuildCall(builder, llvmFunction, rargs, args.size, "")!!
         } else {
-            val landingpad = lazyLandingpad()
+            val unwind = when (exceptionHandler) {
+                ExceptionHandler.Caller -> cleanupLandingpad
+                is ExceptionHandler.Local -> exceptionHandler.unwind
 
-            if (landingpad == null) {
-                // When calling a function that is not marked as nounwind (can throw an exception),
-                // it is required to specify a landingpad to handle exceptions properly.
-                // Runtime C++ function can be marked as non-throwing using `RUNTIME_NOTHROW`.
-                val functionName = llvmFunction.name
-                val message = "no landingpad specified when calling function $functionName without nounwind attr"
-                throw IllegalArgumentException(message)
+                ExceptionHandler.None -> {
+                    // When calling a function that is not marked as nounwind (can throw an exception),
+                    // it is required to specify an unwind label to handle exceptions properly.
+                    // Runtime C++ function can be marked as non-throwing using `RUNTIME_NOTHROW`.
+                    val functionName = llvmFunction.name
+                    val message =
+                            "no exception handler specified when calling function $functionName without nounwind attr"
+                    throw IllegalArgumentException(message)
+                }
             }
 
             val success = basicBlock("call_success", position())
-            val result = LLVMBuildInvoke(builder, llvmFunction, rargs, args.size, success, landingpad, "")!!
+            val result = LLVMBuildInvoke(builder, llvmFunction, rargs, args.size, success, unwind, "")!!
             positionAtEnd(success)
             return result
         }

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

@@ -165,7 +165,7 @@ internal interface CodeContext {
 
     fun genContinue(destination: IrContinue)
 
-    fun genCall(function: LLVMValueRef, args: List<LLVMValueRef>, resultLifetime: Lifetime): LLVMValueRef
+    val exceptionHandler: ExceptionHandler
 
     fun genThrow(exception: LLVMValueRef)
 
@@ -237,7 +237,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
 
         override fun genContinue(destination: IrContinue) = unsupported()
 
-        override fun genCall(function: LLVMValueRef, args: List<LLVMValueRef>, resultLifetime: Lifetime) = unsupported(function)
+        override val exceptionHandler get() = unsupported()
 
         override fun genThrow(exception: LLVMValueRef) = unsupported()
 
@@ -558,14 +558,15 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
             }
         }
 
-        override fun genCall(function: LLVMValueRef, args: List<LLVMValueRef>, resultLifetime: Lifetime) =
-                functionGenerationContext.callAtFunctionScope(function, args, resultLifetime)
+        override val exceptionHandler get() = ExceptionHandler.Caller
 
         override fun genThrow(exception: LLVMValueRef) {
             val objHeaderPtr = functionGenerationContext.bitcast(codegen.kObjHeaderPtr, exception)
             val args = listOf(objHeaderPtr)
 
-            this.genCall(context.llvm.throwExceptionFunction, args, Lifetime.IRRELEVANT)
+            functionGenerationContext.call(
+                    context.llvm.throwExceptionFunction, args, Lifetime.IRRELEVANT, this.exceptionHandler
+            )
             functionGenerationContext.unreachable()
         }
 
@@ -938,10 +939,8 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
             }
         }
 
-        // The call inside [CatchingScope] must be configured to dispatch exception to the scope's handler.
-        override fun genCall(function: LLVMValueRef, args: List<LLVMValueRef>, resultLifetime: Lifetime): LLVMValueRef {
-            val res = functionGenerationContext.call(function, args, resultLifetime, this::landingpad)
-            return res
+        override val exceptionHandler: ExceptionHandler get() = object : ExceptionHandler.Local() {
+            override val unwind get() = landingpad
         }
 
         override fun genThrow(exception: LLVMValueRef) {
@@ -2363,7 +2362,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
 
     private fun call(function: LLVMValueRef, args: List<LLVMValueRef>,
                      resultLifetime: Lifetime = Lifetime.IRRELEVANT): LLVMValueRef {
-        return currentCodeContext.genCall(function, args, resultLifetime)
+        return functionGenerationContext.call(function, args, resultLifetime, currentCodeContext.exceptionHandler)
     }
 
     //-------------------------------------------------------------------------//
@@ -2420,7 +2419,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
             // launcher, so we could optimize out creating slot for 'parameter' in
             // this function.
             val parameter = LLVMGetParam(selector, 0)!!
-            callAtFunctionScope(entryPoint, listOf(parameter), Lifetime.IRRELEVANT)
+            call(entryPoint, listOf(parameter), Lifetime.IRRELEVANT, ExceptionHandler.Caller)
             ret(null)
         }
         return selector

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

@@ -65,7 +65,7 @@ internal class ObjCExportCodeGenerator(
         // TODO: it is required only for Kotlin-to-Objective-C bridges.
         this.forwardingForeignExceptionsTerminatedWith = objcTerminate
 
-        return callAtFunctionScope(function, args, resultLifetime)
+        return call(function, args, resultLifetime, ExceptionHandler.Caller)
     }
 
     fun FunctionGenerationContext.genSendMessage(