[JS] Support the 'names' field in sourcemaps

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/jsAstUtils.kt

@@ -522,17 +522,17 @@ object JsAstUtils {
     }
 }
 
-internal fun <T : JsNode> T.withSource(node: IrElement, context: JsGenerationContext): T {
+internal fun <T : JsNode> T.withSource(node: IrElement, context: JsGenerationContext, originalName: String? = null): T {
-    addSourceInfoIfNeed(node, context)
+    addSourceInfoIfNeed(node, context, originalName)
     return this
 }
 
 @Suppress("NOTHING_TO_INLINE")
-private inline fun <T : JsNode> T.addSourceInfoIfNeed(node: IrElement, context: JsGenerationContext) {
+private inline fun <T : JsNode> T.addSourceInfoIfNeed(node: IrElement, context: JsGenerationContext, originalName: String?) {
 
     val sourceMapsInfo = context.staticContext.backendContext.sourceMapsInfo ?: return
 
-    val location = context.getLocationForIrElement(node) ?: return
+    val location = context.getLocationForIrElement(node, originalName) ?: return
 
     val isNodeFromCurrentModule = context.currentFile.module.descriptor == context.staticContext.backendContext.module
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/JsGenerationContext.kt

@@ -87,9 +87,9 @@ class JsGenerationContext(
 
     fun checkIfHasAssociatedJsCode(symbol: IrFunctionSymbol): Boolean = staticContext.backendContext.getJsCodeForFunction(symbol) != null
 
-    fun getLocationForIrElement(irElement: IrElement): JsLocation? {
+    fun getLocationForIrElement(irElement: IrElement, originalName: String? = null): JsLocation? {
         return locationCache.getOrPut(irElement.startOffset) {
             irElement.getSourceInfo(currentFile.fileEntry) ?: return null
-        }
+        }.copy(name = originalName)
     }
 }

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsLocation.kt

@@ -18,10 +18,11 @@ package org.jetbrains.kotlin.js.backend.ast
 
 import java.io.Reader
 
-data class JsLocation(
+data class JsLocation @JvmOverloads constructor(
     override val file: String,
     override val startLine: Int,
-    override val startChar: Int
+    override val startChar: Int,
+    override val name: String? = null
 ) : JsLocationWithSource {
     override val fileIdentity: Any?
         get() = null
@@ -36,6 +37,11 @@ interface JsLocationWithSource {
     val startLine: Int
     val startChar: Int
 
+    /**
+     * The original name of the entity in the source code that this JS node was generated from.
+     */
+    val name: String?
+
     /**
      * An object to distinguish different files with the same paths
      */

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMap.kt

@@ -28,7 +28,8 @@ class SourceMap(val sourceContentResolver: (String) -> Reader?) {
         for ((index, group) in groups.withIndex()) {
             writer.print("${index + 1}:")
             for (segment in group.segments) {
-                writer.print(" ${segment.generatedColumnNumber + 1}:${segment.sourceLineNumber + 1},${segment.sourceColumnNumber + 1}")
+                val nameIfPresent = if (segment.name != null) "(${segment.name})" else ""
+                writer.print(" ${segment.generatedColumnNumber + 1}:${segment.sourceLineNumber + 1},${segment.sourceColumnNumber + 1}$nameIfPresent")
             }
             writer.println()
         }
@@ -42,8 +43,9 @@ class SourceMap(val sourceContentResolver: (String) -> Reader?) {
             val generatedLine = generatedLines[index]
             val segmentsByColumn = group.segments.map { it.generatedColumnNumber to it }.toMap()
             for (i in generatedLine.indices) {
-                segmentsByColumn[i]?.let { (_, sourceFile, sourceLine, sourceColumn) ->
+                segmentsByColumn[i]?.let { (_, sourceFile, sourceLine, sourceColumn, name) ->
-                    writer.print("<$sourceFile:${sourceLine + 1}:${sourceColumn + 1}>")
+                    val nameIfPresent = if (name != null) "($name)" else ""
+                    writer.print("<$sourceFile:${sourceLine + 1}:${sourceColumn + 1}$nameIfPresent>")
                 }
                 writer.print(generatedLine[i])
             }
@@ -96,7 +98,8 @@ data class SourceMapSegment(
     val generatedColumnNumber: Int,
     val sourceFileName: String?,
     val sourceLineNumber: Int,
-    val sourceColumnNumber: Int
+    val sourceColumnNumber: Int,
+    val name: String?,
 )
 
 class SourceMapGroup {

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMapLocationRemapper.kt

@@ -70,10 +70,10 @@ class SourceMapLocationRemapper(private val sourceMap: SourceMap, private val so
             val segment = findCorrespondingSegment(node)
             val sourceFileName = segment?.sourceFileName
             node.source = if (sourceFileName != null) {
-                val location = JsLocation(sourceMapPathMapper(sourceFileName), segment.sourceLineNumber, segment.sourceColumnNumber)
+                val location =
+                    JsLocation(sourceMapPathMapper(sourceFileName), segment.sourceLineNumber, segment.sourceColumnNumber, segment.name)
                 JsLocationWithEmbeddedSource(location, null) { sourceMap.sourceContentResolver(segment.sourceFileName) }
-            }
+            } else {
-            else {
                 null
             }
         }

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMapParser.kt

@@ -86,6 +86,17 @@ object SourceMapParser {
             }
         }
 
+        val names = jsonObject.properties["names"].let {
+            if (it != null) {
+                val namesProperty = it as? JsonArray ?: return SourceMapError("'names' property is not of array type")
+                namesProperty.elements.map {
+                    (it as? JsonString ?: return SourceMapError("'names' array must contain strings")).value
+                }
+            } else {
+                emptyList()
+            }
+        }
+
         val sourcePathToContent = sources.zip(sourcesContent).associate { it }
 
         val mappings = jsonObject.properties["mappings"] ?: return SourceMapError("'mappings' property not found")
@@ -95,6 +106,7 @@ object SourceMapParser {
         var sourceLine = 0
         var sourceColumn = 0
         var sourceIndex = 0
+        var nameIndex = 0
         val stream = MappingStream(mappings.value)
         val sourceMap = SourceMap { sourcePathToContent[it]?.let { StringReader(it) } }
         var currentGroup = SourceMapGroup().also { sourceMap.groups += it }
@@ -113,17 +125,20 @@ object SourceMapParser {
                 sourceIndex += stream.readInt() ?: return stream.createError("VLQ-encoded source index expected")
                 sourceLine += stream.readInt() ?: return stream.createError("VLQ-encoded source line expected")
                 sourceColumn += stream.readInt() ?: return stream.createError("VLQ-encoded source column expected")
-                if (stream.isEncodedInt) {
+                val name = if (stream.isEncodedInt) {
-                    stream.readInt() ?: return stream.createError("VLQ-encoded name index expected")
+                    nameIndex += stream.readInt() ?: return stream.createError("VLQ-encoded name index expected")
-                }
+                    if (nameIndex !in names.indices) {
+                        return stream.createError("Name index $nameIndex is out of bounds ${names.indices}")
+                    }
+                    names[nameIndex]
+                } else null
 
                 if (sourceIndex !in sources.indices) {
                     return stream.createError("Source index $sourceIndex is out of bounds ${sources.indices}")
                 }
-                currentGroup.segments += SourceMapSegment(jsColumn, sourceRoot + sources[sourceIndex], sourceLine, sourceColumn)
+                currentGroup.segments += SourceMapSegment(jsColumn, sourceRoot + sources[sourceIndex], sourceLine, sourceColumn, name)
-            }
+            } else {
-            else {
+                currentGroup.segments += SourceMapSegment(jsColumn, null, -1, -1, null)
-                currentGroup.segments += SourceMapSegment(jsColumn, null, -1, -1)
             }
 
             when {

js/js.sourcemap/src/org/jetbrains/kotlin/js/sourceMap/SourceMap3Builder.kt

@@ -17,15 +17,25 @@ class SourceMap3Builder(
     private val textOutput: TextOutput,
     private val pathPrefix: String
 ) : SourceMapBuilder {
-    private val out = StringBuilder(8192)
+
-    private val sources: TObjectIntHashMap<SourceKey> = object : TObjectIntHashMap<SourceKey>() {
+    private class ObjectIntHashMap<T> : TObjectIntHashMap<T>() {
-        override fun get(key: SourceKey): Int {
+        override fun get(key: T): Int {
             val index = index(key)
             return if (index < 0) -1 else _values[index]
         }
     }
+
+    private val out = StringBuilder(8192)
+
+    private val sources = ObjectIntHashMap<SourceKey>()
     private val orderedSources = mutableListOf<String>()
     private val orderedSourceContentSuppliers = mutableListOf<Supplier<Reader?>>()
+
+    private val names = ObjectIntHashMap<String>()
+    private val orderedNames = mutableListOf<String>()
+    private var previousNameIndex = 0
+    private var previousPreviousNameIndex = 0
+
     private var previousGeneratedColumn = -1
     private var previousSourceIndex = 0
     private var previousSourceLine = 0
@@ -45,7 +55,9 @@ class SourceMap3Builder(
             json.properties["file"] = JsonString(generatedFile.name)
         appendSources(json)
         appendSourcesContent(json)
-        json.properties["names"] = JsonArray()
+        json.properties["names"] = JsonArray(
+            orderedNames.mapTo(mutableListOf()) { JsonString(it) }
+        )
         json.properties["mappings"] = JsonString(out.toString())
         return json.toString()
     }
@@ -97,16 +109,33 @@ class SourceMap3Builder(
         return sourceIndex
     }
 
+    private fun getNameIndex(name: String): Int {
+        var nameIndex = names[name]
+        if (nameIndex == -1) {
+            nameIndex = orderedNames.size
+            names.put(name, nameIndex)
+            orderedNames.add(name)
+        }
+        return nameIndex
+    }
+
     override fun addMapping(
         source: String,
         fileIdentity: Any?,
         sourceContent: Supplier<Reader?>,
         sourceLine: Int,
-        sourceColumn: Int
+        sourceColumn: Int,
+        name: String?,
     ) {
         val sourceIndex = getSourceIndex(source.replace(File.separatorChar, '/'), fileIdentity, sourceContent)
 
-        if (!currentMappingIsEmpty && previousSourceIndex == sourceIndex && previousSourceLine == sourceLine && previousSourceColumn == sourceColumn) {
+        val nameIndex = name?.let(this::getNameIndex) ?: -1
+
+        if (!currentMappingIsEmpty &&
+            previousSourceIndex == sourceIndex &&
+            previousSourceLine == sourceLine &&
+            previousSourceColumn == sourceColumn
+        ) {
             return
         }
 
@@ -121,6 +150,11 @@ class SourceMap3Builder(
         Base64VLQ.encode(out, sourceColumn - previousSourceColumn)
         previousSourceColumn = sourceColumn
 
+        if (nameIndex >= 0) {
+            Base64VLQ.encode(out, nameIndex - previousNameIndex)
+            previousNameIndex = nameIndex
+        }
+
         currentMappingIsEmpty = false
     }
 
@@ -148,11 +182,13 @@ class SourceMap3Builder(
             previousPreviousSourceIndex = previousSourceIndex
             previousPreviousSourceLine = previousSourceLine
             previousPreviousSourceColumn = previousSourceColumn
+            previousPreviousNameIndex = previousNameIndex
         } else {
             out.setLength(previousMappingOffset)
             previousSourceIndex = previousPreviousSourceIndex
             previousSourceLine = previousPreviousSourceLine
             previousSourceColumn = previousPreviousSourceColumn
+            previousNameIndex = previousPreviousNameIndex
         }
     }
 

js/js.sourcemap/src/org/jetbrains/kotlin/js/sourceMap/SourceMapBuilderConsumer.kt

@@ -59,7 +59,7 @@ class SourceMapBuilderConsumer(
                     } else {
                         { null }
                     }
-                    mappingConsumer.addMapping(sourceFilePath, null, contentSupplier, startLine, startChar)
+                    mappingConsumer.addMapping(sourceFilePath, null, contentSupplier, startLine, startChar, null)
                 } catch (e: IOException) {
                     throw RuntimeException("IO error occurred generating source maps", e)
                 }
@@ -85,7 +85,8 @@ class SourceMapBuilderConsumer(
                     sourceInfo.fileIdentity,
                     contentSupplier,
                     sourceInfo.startLine,
-                    sourceInfo.startChar
+                    sourceInfo.startChar,
+                    sourceInfo.name
                 )
             }
 

js/js.sourcemap/src/org/jetbrains/kotlin/js/sourceMap/SourceMapMappingConsumer.java

@@ -16,7 +16,7 @@ public interface SourceMapMappingConsumer {
 
     void addMapping(
             @NotNull String source, @Nullable Object fileIdentity, @NotNull Supplier<Reader> sourceSupplier,
-            int sourceLine, int sourceColumn
+            int sourceLine, int sourceColumn, @Nullable String name
     );
 
     void addEmptyMapping();