From 7503f134c23b57dc9d2e3b9a0b2b627bde7d0741 Mon Sep 17 00:00:00 2001
From: Alexander Udalov <alexander.udalov@jetbrains.com>
Date: Mon, 3 Aug 2020 22:48:00 +0200
Subject: [PATCH] IR: use IdSignature to compare classes in
 FqNameEqualityChecker

This is both simpler and a lot more performant.
---
 .../ir/symbols/IrClassifierEqualityChecker.kt | 75 ++-----------------
 1 file changed, 5 insertions(+), 70 deletions(-)

diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/IrClassifierEqualityChecker.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/IrClassifierEqualityChecker.kt
index 9b8e16bdda0..11ad61fa45f 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/IrClassifierEqualityChecker.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/symbols/IrClassifierEqualityChecker.kt
@@ -5,82 +5,17 @@
 
 package org.jetbrains.kotlin.ir.symbols
 
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.descriptors.ClassifierDescriptor
-import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
-import org.jetbrains.kotlin.ir.declarations.IrClass
-import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
-import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
-import org.jetbrains.kotlin.ir.declarations.IrSymbolOwner
-import org.jetbrains.kotlin.ir.util.isLocalClass
-import org.jetbrains.kotlin.name.FqName
-import org.jetbrains.kotlin.resolve.DescriptorUtils
-import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
-
 interface IrClassifierEqualityChecker {
     fun areEqual(left: IrClassifierSymbol, right: IrClassifierSymbol): Boolean
 
     fun getHashCode(symbol: IrClassifierSymbol): Int
 }
 
-@OptIn(ObsoleteDescriptorBasedAPI::class)
 object FqNameEqualityChecker : IrClassifierEqualityChecker {
-    override fun areEqual(left: IrClassifierSymbol, right: IrClassifierSymbol): Boolean {
-        if (left === right) return true
-        if (!left.isBound || !right.isBound) {
-            return checkViaDescriptors(left.descriptor, right.descriptor)
-        }
-        return checkViaDeclarations(left.owner, right.owner)
-    }
+    override fun areEqual(left: IrClassifierSymbol, right: IrClassifierSymbol): Boolean =
+        left === right ||
+                left.isPublicApi && right.isPublicApi && left.signature == right.signature
 
-    override fun getHashCode(symbol: IrClassifierSymbol): Int {
-        if (symbol.isBound) {
-            val owner = symbol.owner
-            if (owner is IrClass && !owner.isLocalClass()) {
-                return owner.fqName.hashCode()
-            }
-            return owner.hashCode()
-        }
-
-        val descriptor = symbol.descriptor
-        if (descriptor is ClassDescriptor && !DescriptorUtils.isLocal(descriptor)) {
-            return descriptor.fqNameSafe.hashCode()
-        }
-        return descriptor.hashCode()
-    }
-
-    private val IrDeclarationWithName.fqName: FqName?
-        get() {
-            val parentFqName = when (val parent = parent) {
-                is IrPackageFragment -> parent.fqName
-                is IrDeclarationWithName -> parent.fqName
-                else -> return null
-            }
-            return parentFqName?.child(name)
-        }
-
-    private fun areFqNamesEqual(c1: IrDeclarationWithName, c2: IrDeclarationWithName): Boolean {
-        if (c1.name != c2.name) return false
-
-        val parent1 = c1.parent
-        val parent2 = c2.parent
-        return when (parent1) {
-            is IrPackageFragment -> parent2 is IrPackageFragment && parent1.fqName == parent2.fqName
-            is IrDeclarationWithName -> parent2 is IrDeclarationWithName && areFqNamesEqual(parent1, parent2)
-            else -> false
-        }
-    }
-
-    private fun checkViaDeclarations(c1: IrSymbolOwner, c2: IrSymbolOwner): Boolean {
-        if (c1 is IrClass && c2 is IrClass) {
-            if (c1.isLocalClass() || c2.isLocalClass())
-                return c1 === c2 // Local declarations should be identical
-
-            return areFqNamesEqual(c1, c2)
-        }
-
-        return c1 == c2
-    }
-
-    private fun checkViaDescriptors(c1: ClassifierDescriptor, c2: ClassifierDescriptor) = c1.typeConstructor == c2.typeConstructor
+    override fun getHashCode(symbol: IrClassifierSymbol): Int =
+        if (symbol.isPublicApi) symbol.signature.hashCode() else symbol.hashCode()
 }