From 49bedf1cc3bb54c597b595383cf4b1348d27b8b1 Mon Sep 17 00:00:00 2001
From: Konstantin Anisimov <konstantin.anisimov@jetbrains.com>
Date: Mon, 9 Jan 2017 10:51:37 +0700
Subject: [PATCH] Comments added

---
 .../backend/konan/lower/FunctionInlining.kt   | 27 +++++++++----------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
index c7145b69056..5c41d1a313e 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/FunctionInlining.kt
@@ -9,7 +9,6 @@ import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.impl.IrBlockBodyImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrBlockImpl
 import org.jetbrains.kotlin.ir.util.DeepCopyIrTree
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
@@ -30,25 +29,25 @@ internal class FunctionInlining(val context: Context): IrElementTransformerVoid(
     //-------------------------------------------------------------------------//
 
     override fun visitCall(expression: IrCall): IrExpression {
-        val functionDescriptor = expression.descriptor as FunctionDescriptor                //
-        if (!functionDescriptor.isInline) return super.visitCall(expression)                // function is not to be inlined - do nothing
+        val functionDescriptor = expression.descriptor as FunctionDescriptor
+        if (!functionDescriptor.isInline) return super.visitCall(expression)                // Function is not to be inlined - do nothing.
 
-        val functionDeclaration = context.ir.moduleIndex.functions[functionDescriptor]      // get FunctionDeclaration by FunctionDescriptor
-        if (functionDeclaration == null) return super.visitCall(expression)                 // TODO what if we do not have declaration?
-        val copyFuncDeclaration = functionDeclaration.accept(DeepCopyIrTree(), null) as IrFunction
+        val functionDeclaration = context.ir.moduleIndex.functions[functionDescriptor]      // Get FunctionDeclaration by FunctionDescriptor.
+        if (functionDeclaration == null) return super.visitCall(expression)                 // Function is declared in another module.
+        val copyFuncDeclaration = functionDeclaration.accept(DeepCopyIrTree(), null) as IrFunction // Create copy of the function.
 
         val body        = copyFuncDeclaration.body!! as IrBlockBody
-        val statements  = removeReturn(body.statements)
+        val statements  = removeReturn(body.statements)                                     // Replace "return" with its value.
         val startOffset = copyFuncDeclaration.startOffset
         val endOffset   = copyFuncDeclaration.endOffset
         val returnType  = copyFuncDeclaration.descriptor.returnType!!
-        val irBlock     = IrBlockImpl(startOffset, endOffset, returnType, null, statements) // create
+        val irBlock     = IrBlockImpl(startOffset, endOffset, returnType, null, statements) // Create IrBlock containing function statements.
 
-        val parameterToExpression = expression.getArguments()
+        val parameterToExpression = expression.getArguments()                               // Build map parameter -> expression.
         val parametersTransformer = ParametersTransformer(parameterToExpression)
-        irBlock.accept(parametersTransformer, null)
+        irBlock.accept(parametersTransformer, null)                                         // Replace parameters with expression.
 
-        return irBlock
+        return irBlock                                                                      // Return newly created IrBlock instead of IrCall.
     }
 
     //-------------------------------------------------------------------------//
@@ -66,10 +65,10 @@ internal class ParametersTransformer(val parameterToExpression: List <Pair<Param
 
     override fun visitGetValue(expression: IrGetValue): IrExpression {
         val descriptor = expression.descriptor
-        if (descriptor !is ParameterDescriptor) {
+        if (descriptor !is ParameterDescriptor) {                                           // TODO do we need this check?
             return super.visitGetValue(expression)
         }
-        val parExp = parameterToExpression.find { it.first == descriptor }
-        return parExp?.let { parExp.second } ?: super.visitGetValue(expression)
+        val parExp = parameterToExpression.find { it.first == descriptor }                  // Find expression to replace this parameter.
+        return parExp?.let { parExp.second } ?: super.visitGetValue(expression)             // TODO should we proceed with IR iteration here?
     }
 }
\ No newline at end of file