diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/InlineGraphTracker.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/InlineGraphTracker.kt
new file mode 100644
index 00000000000..8936152ee84
--- /dev/null
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/InlineGraphTracker.kt
@@ -0,0 +1,186 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.backend.js.ic
+
+import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.declarations.IrFile
+import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
+import org.jetbrains.kotlin.ir.expressions.IrCall
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.dump
+import org.jetbrains.kotlin.ir.util.file
+import org.jetbrains.kotlin.ir.util.render
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
+import org.jetbrains.kotlin.utils.DFS
+import java.security.MessageDigest
+
+fun ByteArray.md5(): Hash {
+    val d = MessageDigest.getInstance("MD5").digest(this)!!
+    return ((d[0].toLong() and 0xFFL)
+            or ((d[1].toLong() and 0xFFL) shl 8)
+            or ((d[2].toLong() and 0xFFL) shl 16)
+            or ((d[3].toLong() and 0xFFL) shl 24)
+            or ((d[4].toLong() and 0xFFL) shl 32)
+            or ((d[5].toLong() and 0xFFL) shl 40)
+            or ((d[6].toLong() and 0xFFL) shl 48)
+            or ((d[7].toLong() and 0xFFL) shl 56))
+}
+
+class InlineFunctionFlatHashBuilder : IrElementVisitorVoid {
+    override fun visitElement(element: IrElement) {
+        element.acceptChildren(this, null)
+    }
+
+
+    private val fileToHash: MutableMap<IrFile, MutableMap<IrSimpleFunction, FlatHash>> = mutableMapOf()
+
+    private var currentMap: MutableMap<IrSimpleFunction, FlatHash>? = null
+
+    override fun visitFile(declaration: IrFile) {
+        currentMap = fileToHash.getOrPut(declaration) { mutableMapOf() }
+        declaration.acceptChildren(this, null)
+        currentMap = null
+    }
+
+    override fun visitSimpleFunction(declaration: IrSimpleFunction) {
+        if (declaration.isInline) {
+            val m = currentMap ?: error("No graph map set for ${declaration.render()}")
+            m[declaration] = declaration.dump().toByteArray().md5()
+        }
+        // do not go deeper since local declaration cannot be public api
+    }
+
+    val idToHashMap: Map<IrSimpleFunction, FlatHash> get() = fileToHash.values.flatMap { it.entries }.map { it.key to it.value }.toMap()
+
+}
+
+interface InlineFunctionHashProvider {
+    fun hashForExternalFunction(declaration: IrSimpleFunction): TransHash?
+}
+
+class InlineFunctionHashBuilder(
+    private val hashProvider: InlineFunctionHashProvider,
+    private val flatHashes: Map<IrSimpleFunction, FlatHash>
+) {
+    private val inlineGraph: MutableMap<IrSimpleFunction, Set<IrSimpleFunction>> = mutableMapOf()
+
+    private inner class GraphBuilder : IrElementVisitor<Unit, MutableSet<IrSimpleFunction>> {
+
+        override fun visitElement(element: IrElement, data: MutableSet<IrSimpleFunction>) {
+            element.acceptChildren(this, data)
+        }
+
+        override fun visitSimpleFunction(declaration: IrSimpleFunction, data: MutableSet<IrSimpleFunction>) {
+            val newGraph = mutableSetOf<IrSimpleFunction>()
+            inlineGraph[declaration] = newGraph
+            declaration.acceptChildren(this, newGraph)
+        }
+
+
+        override fun visitCall(expression: IrCall, data: MutableSet<IrSimpleFunction>) {
+            val callee = expression.symbol.owner
+
+            if (callee.isInline) {
+                data.add(callee)
+            }
+
+            expression.acceptChildren(this, data)
+        }
+    }
+
+
+    private fun topologicalOrder(): List<IrSimpleFunction> {
+        return DFS.topologicalOrder(inlineGraph.keys) {
+            inlineGraph[it]?.filter { f -> f in inlineGraph } ?: run {
+//                assert() not in current module
+                emptySet()
+            }
+        }
+    }
+
+    private fun checkCircles() {
+
+        val visited = mutableSetOf<IrSimpleFunction>()
+
+        // TODO: check whether algorithm is correct
+        for (f in inlineGraph.keys) {
+
+            fun walk(current: IrSimpleFunction) {
+                if (!visited.add(current)) {
+                    error("Inline circle detected: ${current.render()} into ${f.render()}")
+                }
+
+                inlineGraph[current]?.let {
+                    it.forEach { callee -> walk(callee) }
+                }
+
+                visited.remove(current)
+            }
+
+            walk(f)
+
+            assert(visited.isEmpty())
+        }
+    }
+
+
+    fun buildHashes(dirtyFiles: Collection<IrFile>): Map<IrSimpleFunction, TransHash> {
+
+        dirtyFiles.forEach { it.acceptChildren(GraphBuilder(), mutableSetOf()) }
+
+        checkCircles()
+
+        val rpo = topologicalOrder()
+
+        val computedHashes = mutableMapOf<IrSimpleFunction, TransHash>()
+
+        fun transHash(callee: IrSimpleFunction): TransHash {
+            return computedHashes[callee] ?: hashProvider.hashForExternalFunction(callee)
+            ?: error("Internal error: No has found for ${callee.render()}")
+        }
+
+        for (f in rpo.asReversed()) {
+            if (!f.isInline) continue
+            val stringHash = buildString {
+                val callees = inlineGraph[f]
+                    ?: error("Expected to be in")
+                // TODO: should it be a kind of stable order?
+                for (callee in callees) {
+                    val hash = transHash(callee)
+                    append(hash.toString(Character.MAX_RADIX))
+                }
+
+                append(flatHashes[f] ?: error("Internal error: No flat hash for ${f.render()}"))
+            }
+
+            computedHashes[f] = stringHash.toByteArray().md5()
+        }
+
+        return computedHashes
+    }
+
+    fun buildInlineGraph(computedHashed: Map<IrSimpleFunction, TransHash>): Map<IrFile, Collection<Pair<IdSignature, TransHash>>> {
+        val perFileInlineGraph = inlineGraph.entries.groupBy({ it.key.file }) {
+            it.value
+        }
+
+        return perFileInlineGraph.map {
+            it.key to it.value.flatMap { edges ->
+                edges.mapNotNull { callee ->
+                    // TODO: use resolved FO
+                    if (!callee.isFakeOverride) {
+                        val signature = callee.symbol.signature ?: error("Expecting signature for ${callee.render()}")
+                        if (signature.visibleCrossFile) {
+                            signature to (computedHashed[callee] ?: hashProvider.hashForExternalFunction(callee)
+                            ?: error("Internal error: No has found for ${callee.render()}"))
+                        } else null
+                    } else null
+                }
+            }
+        }.toMap()
+    }
+}