Fix performance bug, review feedback on indexer changes (#818)

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

@@ -216,6 +216,9 @@ internal class Context(config: KonanConfig) : KonanBackendContext(config) {
     var phase: KonanPhase? = null
     var depth: Int = 0
 
+    // Cache used for source offset->(line,column) mapping.
+    val fileEntryCache = mutableMapOf<String, SourceManager.FileEntry>()
+
     protected fun separator(title: String) {
         println("\n\n--- ${title} ----------------------\n")
     }

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

@@ -93,9 +93,9 @@ class NaiveSourceBasedFileEntryImpl(override val name: String) : SourceManager.F
 
 //-----------------------------------------------------------------------------//
 
-class IrFileImpl(fileName: String) : IrFile {
+class IrFileImpl(entry: SourceManager.FileEntry) : IrFile {
 
-    override val fileEntry = NaiveSourceBasedFileEntryImpl(fileName)
+    override val fileEntry = entry
 
     //-------------------------------------------------------------------------//
 

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

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
+import org.jetbrains.kotlin.ir.SourceManager
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltinOperatorDescriptorBase
 import org.jetbrains.kotlin.ir.expressions.*
@@ -1433,8 +1434,15 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
     }
 
     //-------------------------------------------------------------------------//
+    fun getFileEntry(sourceFileName: String): SourceManager.FileEntry {
+        // We must cache file entries, otherwise we reparse same file many times.
+        return context.fileEntryCache.getOrPut(sourceFileName) {
+            NaiveSourceBasedFileEntryImpl(sourceFileName)
+        }
+    }
 
-    private inner class ReturnableBlockScope(val returnableBlock: IrReturnableBlockImpl) : FileScope(IrFileImpl(returnableBlock.sourceFileName)) {
+    private inner class ReturnableBlockScope(val returnableBlock: IrReturnableBlockImpl) :
+            FileScope(IrFileImpl(getFileEntry(returnableBlock.sourceFileName))) {
 
         var bbExit : LLVMBasicBlockRef? = null
         var resultPhi : LLVMValueRef? = null