backend: properly import functions from runtime

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

@@ -1,8 +1,6 @@
 package org.jetbrains.kotlin.backend.native.llvm
 
-import llvm.LLVMCreateBuilder
-import llvm.LLVMDisposeBuilder
-import llvm.LLVMOpaqueModule
+import llvm.*
 import org.jetbrains.kotlin.backend.native.ModuleIndex
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 
@@ -11,6 +9,21 @@ internal class Context(val irModule: IrModuleFragment, val runtime: Runtime, val
 
     val llvmBuilder = LLVMCreateBuilder()
 
+    private fun importFunction(name: String, otherModule: LLVMOpaqueModule): LLVMOpaqueValue {
+        if (LLVMGetNamedFunction(llvmModule, name) != null) {
+            throw IllegalArgumentException("function $name already exists")
+        }
+
+        val externalFunction = LLVMGetNamedFunction(otherModule, name)!!
+
+        val functionType = getFunctionType(externalFunction)
+        return LLVMAddFunction(llvmModule, name, functionType)!!
+    }
+
+    private fun importRtFunction(name: String) = importFunction(name, runtime.llvmModule)
+
+    val allocInstanceFunction = importRtFunction("AllocInstance")
+
     fun dispose() {
         LLVMDisposeBuilder(llvmBuilder)
     }

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

@@ -22,7 +22,6 @@ fun emitLLVM(module: IrModuleFragment, runtimeFile: String, outFile: String) {
     val context = Context(module, runtime, llvmModule) // TODO: dispose
 
     module.acceptVoid(RTTIGeneratorVisitor(context))
-    context.runtime.importRuntime(llvmModule)
     module.acceptVoid(CodeGeneratorVisitor(context))
     memScoped {
         val errorRef = alloc(Int8Box.ref)
@@ -180,7 +179,7 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
     private fun evaluateConstructorCall(variableName: String, callee: IrCall, args: MutableList<LLVMOpaqueValue?>): LLVMOpaqueValue? {
         memScoped {
             val params = allocNativeArrayOf(LLVMOpaqueValue, generator.typeInfoValue((callee.descriptor as ClassConstructorDescriptor).containingDeclaration), Int32(1).getLlvmValue())
-            val thisValue = LLVMBuildCall(context.llvmBuilder, context.runtime.allocInstanceFunction, params[0], 2, variableName)
+            val thisValue = LLVMBuildCall(context.llvmBuilder, context.allocInstanceFunction, params[0], 2, variableName)
 
 
             val constructorParams: MutableList<LLVMOpaqueValue?> = mutableListOf()

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

@@ -97,4 +97,9 @@ internal fun NativeArray<Int8Box>.asCompileTimeValue(size: Int): ConstArray {
     return ConstArray(int8Type, (0 .. size-1).map {
         Int8(this[it].value)
     })
+}
+
+internal fun getFunctionType(ptrToFunction: LLVMOpaqueValue?): LLVMOpaqueType {
+    val typeOfPtrToFunction = LLVMTypeOf(ptrToFunction)
+    return LLVMGetElementType(typeOfPtrToFunction)!!
 }

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

@@ -34,15 +34,6 @@ class Runtime(private val bitcodeFile: String) {
     val fieldTableRecordType = LLVMGetTypeByName(llvmModule, "struct.FieldTableRecord")
     val methodTableRecordType = LLVMGetTypeByName(llvmModule, "struct.MethodTableRecord")
     val globalhHashType = LLVMGetTypeByName(llvmModule, "struct.GlobalHash")
-    val allocInstanceFunction = LLVMGetNamedFunction(llvmModule, "AllocInstance")
-
-    fun importRuntime(module: LLVMOpaqueModule) {
-        memScoped {
-            val params = allocNativeArrayOf(LLVMOpaqueType, pointerType(typeInfoType), LLVMInt32Type())
-            val functionAllocInstanceType = LLVMFunctionType(pointerType(LLVMInt8Type()),params[0], 2, 0)
-            LLVMAddFunction(module, "AllocInstance", functionAllocInstanceType)
-        }
-    }
 
     val target = LLVMGetTarget(llvmModule)!!.asCString().toString()