From 0e54e00e48cfdbd4ad9cf4e9759261a80d9f3c6c Mon Sep 17 00:00:00 2001
From: Igor Yakovlev <igor.yakovlev@jetbrains.com>
Date: Fri, 28 Oct 2022 10:26:12 +0200
Subject: [PATCH] [WASM] Make object creation inside constructors

---
 .../backend/wasm/ir2wasm/BodyGenerator.kt     | 33 +++++++++++++------
 .../wasm/ir2wasm/DeclarationGenerator.kt      |  4 +++
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
index 5402f6f117d..79e075760f2 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.backend.wasm.utils.*
 import org.jetbrains.kotlin.backend.wasm.utils.isCanonical
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.backend.js.lower.PrimaryConstructorLowering
 import org.jetbrains.kotlin.ir.backend.js.utils.erasedUpperBound
 import org.jetbrains.kotlin.ir.backend.js.utils.findUnitGetInstanceFunction
 import org.jetbrains.kotlin.ir.backend.js.utils.isDispatchReceiver
@@ -262,9 +263,8 @@ class BodyGenerator(
             return
         }
 
-        generateAnyParameters(klassSymbol)
-
         if (expression.symbol.owner.hasWasmPrimitiveConstructorAnnotation()) {
+            generateAnyParameters(klassSymbol)
             for (i in 0 until expression.valueArgumentsCount) {
                 generateExpression(expression.getValueArgument(i)!!)
             }
@@ -272,14 +272,7 @@ class BodyGenerator(
             return
         }
 
-        val irFields: List<IrField> = klass.allFields(backendContext.irBuiltIns)
-        irFields.forEachIndexed { index, field ->
-            if (index > 1) {
-                generateDefaultInitializerForType(context.transformType(field.type), body)
-            }
-        }
-
-        body.buildStructNew(wasmGcType)
+        body.buildRefNull(WasmHeapType.Simple.NullNone) // this = null
         generateCall(expression)
     }
 
@@ -296,6 +289,26 @@ class BodyGenerator(
         body.buildConstI32(0) // Any::_hashCode
     }
 
+    fun generateObjectCreationPrefixIfNeeded(constructor: IrConstructor) {
+        val parentClass = constructor.parentAsClass
+        if (constructor.origin == PrimaryConstructorLowering.SYNTHETIC_PRIMARY_CONSTRUCTOR) return
+        if (parentClass.isAbstractOrSealed) return
+        val thisParameter = context.referenceLocal(parentClass.thisReceiver!!.symbol)
+        body.buildGetLocal(thisParameter)
+        body.buildInstr(WasmOp.REF_IS_NULL)
+        body.buildIf("this_init")
+        generateAnyParameters(parentClass.symbol)
+        val irFields: List<IrField> = parentClass.allFields(backendContext.irBuiltIns)
+        irFields.forEachIndexed { index, field ->
+            if (index > 1) {
+                generateDefaultInitializerForType(context.transformType(field.type), body)
+            }
+        }
+        body.buildStructNew(context.referenceGcType(parentClass.symbol))
+        body.buildSetLocal(thisParameter)
+        body.buildEnd()
+    }
+
     override fun visitDelegatingConstructorCall(expression: IrDelegatingConstructorCall) {
         val klass = context.irFunction.parentAsClass
 
diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
index 15e36294e5d..3a0fc44319b 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt
@@ -133,6 +133,10 @@ class DeclarationGenerator(
             isGetUnitFunction = declaration == unitGetInstanceFunction
         )
 
+        if (declaration is IrConstructor) {
+            bodyBuilder.generateObjectCreationPrefixIfNeeded(declaration)
+        }
+
         require(declaration.body is IrBlockBody) { "Only IrBlockBody is supported" }
         declaration.body?.acceptVoid(bodyBuilder)