backend.konan: support function types in codegen

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

@@ -154,6 +154,7 @@ internal class CodeGenerator(override val context: Context) : ContextUtils {
     fun lastBasicBlock(): LLVMBasicBlockRef? = LLVMGetLastBasicBlock(currentFunction!!.llvmFunction)
 
     fun functionLlvmValue(descriptor: FunctionDescriptor) = descriptor.llvmFunction
+    fun functionEntryPointAddress(descriptor: FunctionDescriptor) = descriptor.entryPointAddress.llvm
     fun functionHash(descriptor: FunctionDescriptor): LLVMValueRef = descriptor.functionName.localHash.llvm
 
     fun br(bbLabel: LLVMBasicBlockRef): LLVMValueRef {

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

@@ -1,6 +1,7 @@
 package org.jetbrains.kotlin.backend.konan.llvm
 
 import llvm.*
+import org.jetbrains.kotlin.backend.konan.isUnboundCallableReference
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.types.KotlinType
 
@@ -8,6 +9,7 @@ internal fun ContextUtils.getLLVMType(type: KotlinType): LLVMTypeRef {
     return when {
         // Nullable types must be represented as objects for boxing.
         type.isMarkedNullable -> this.kObjHeaderPtr
+        type.isUnboundCallableReference() -> int8TypePtr
         KotlinBuiltIns.isBoolean(type) -> LLVMInt1Type()
         KotlinBuiltIns.isByte(type) -> LLVMInt8Type()
         KotlinBuiltIns.isShort(type) || KotlinBuiltIns.isChar(type) -> LLVMInt16Type()

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

@@ -4,6 +4,7 @@ import kotlinx.cinterop.*
 import llvm.*
 import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.builtins.functions.FunctionInvokeDescriptor
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.ir.IrElement
@@ -607,12 +608,14 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
             is IrTry                 -> return evaluateTry                (                 value)
             is IrStringConcatenation -> return evaluateStringConcatenation(tmpVariableName, value)
             is IrBlockBody           -> return evaluateBlock              (tmpVariableName, value as IrStatementContainer)
+            is IrComposite           -> return evaluateBlock              (tmpVariableName, value)
             is IrWhileLoop           -> return evaluateWhileLoop          (                 value)
             is IrDoWhileLoop         -> return evaluateDoWhileLoop        (                 value)
             is IrVararg              -> return evaluateVararg             (tmpVariableName, value)
             is IrBreak               -> return evaluateBreak              (                 value)
             is IrContinue            -> return evaluateContinue           (                 value)
             is IrGetObjectValue      -> return evaluateGetObjectValue     (tmpVariableName, value)
+            is IrCallableReference   -> return evaluateCallableReference  (tmpVariableName, value)
             null                     -> return null
             else                     -> {
                 TODO("${ir2string(value)}")
@@ -1549,9 +1552,19 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
 
     //-------------------------------------------------------------------------//
 
+    private fun evaluateCallableReference(tmpVariableName: String, expression: IrCallableReference): LLVMValueRef {
+        assert (expression.type.isUnboundCallableReference())
+        assert (expression.getArguments().isEmpty())
+        val entry = codegen.functionEntryPointAddress(expression.descriptor as FunctionDescriptor)
+        return entry
+    }
+
+    //-------------------------------------------------------------------------//
+
     private fun evaluateFunctionCall(tmpVariableName: String, callee: IrCall, args: List<LLVMValueRef>): LLVMValueRef {
         val descriptor:FunctionDescriptor = callee.descriptor as FunctionDescriptor
         when (descriptor) {
+            is FunctionInvokeDescriptor        -> return evaluateFunctionInvoke    (tmpVariableName, descriptor, args)
             is IrBuiltinOperatorDescriptorBase -> return evaluateOperatorCall      (tmpVariableName, callee,     args)
             is ClassConstructorDescriptor      -> return evaluateConstructorCall   (tmpVariableName, callee,     args)
             else                               -> return evaluateSimpleFunctionCall(tmpVariableName, descriptor, args)
@@ -1560,6 +1573,35 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
 
     //-------------------------------------------------------------------------//
 
+    private val functionImplUnboundRefGetter by lazy {
+        context.builtIns.getKonanInternalClass("FunctionImpl")
+                .unsubstitutedMemberScope.getContributedDescriptors()
+                .filterIsInstance<PropertyDescriptor>()
+                .single { it.name.asString() == "unboundRef" }
+                .getter!!
+    }
+
+    private fun evaluateFunctionInvoke(tmpVariableName: String,
+                                       descriptor: FunctionInvokeDescriptor,
+                                       args: List<LLVMValueRef>): LLVMValueRef {
+
+        // Note: the whole function code below is written in the assumption that
+        // `invoke` method receiver is passed as first argument.
+
+        val functionImpl = args[0]
+
+        val unboundRefType = codegen.getLlvmFunctionType(descriptor)
+
+        val unboundRef = evaluateSimpleFunctionCall(codegen.newVar(),
+                functionImplUnboundRefGetter, listOf(functionImpl))
+
+        val entryPtr = codegen.bitcast(pointerType(unboundRefType), unboundRef, "entry")
+
+        return call(descriptor, entryPtr, args, tmpVariableName)
+    }
+
+    //-------------------------------------------------------------------------//
+
     private fun evaluateSimpleFunctionCall(tmpVariableName: String, descriptor: FunctionDescriptor, args: List<LLVMValueRef>): LLVMValueRef {
         //logger.log("evaluateSimpleFunctionCall : $tmpVariableName = ${ir2string(value)}")
         if (descriptor.isOverridable)