[WASM] Initialize constant fields by wasm-initializers

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt

@@ -105,25 +105,8 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
         }
     }
 
-    override fun visitConst(expression: IrConst<*>) {
+    override fun visitConst(expression: IrConst<*>): Unit =
-        when (val kind = expression.kind) {
+        generateConstExpression(expression, body, context)
-            is IrConstKind.Null -> generateDefaultInitializerForType(context.transformType(expression.type), body)
-            is IrConstKind.Boolean -> body.buildConstI32(if (kind.valueOf(expression)) 1 else 0)
-            is IrConstKind.Byte -> body.buildConstI32(kind.valueOf(expression).toInt())
-            is IrConstKind.Short -> body.buildConstI32(kind.valueOf(expression).toInt())
-            is IrConstKind.Int -> body.buildConstI32(kind.valueOf(expression))
-            is IrConstKind.Long -> body.buildConstI64(kind.valueOf(expression))
-            is IrConstKind.Char -> body.buildConstI32(kind.valueOf(expression).code)
-            is IrConstKind.Float -> body.buildConstF32(kind.valueOf(expression))
-            is IrConstKind.Double -> body.buildConstF64(kind.valueOf(expression))
-            is IrConstKind.String -> {
-                body.buildConstI32Symbol(context.referenceStringLiteral(kind.valueOf(expression)))
-                body.buildConstI32(kind.valueOf(expression).length)
-                body.buildCall(context.referenceFunction(wasmSymbols.stringGetLiteral))
-            }
-            else -> error("Unknown constant kind")
-        }
-    }
 
     override fun visitGetField(expression: IrGetField) {
         val field: IrField = expression.symbol.owner

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/DeclarationGenerator.kt

@@ -20,6 +20,9 @@ import org.jetbrains.kotlin.ir.backend.js.utils.getJsNameOrKotlinName
 import org.jetbrains.kotlin.ir.backend.js.utils.realOverrideTarget
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
+import org.jetbrains.kotlin.ir.expressions.IrConst
+import org.jetbrains.kotlin.ir.expressions.IrConstKind
+import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
@@ -364,13 +367,21 @@ class DeclarationGenerator(val context: WasmModuleCodegenContext) : IrElementVis
 
         val initBody = mutableListOf<WasmInstr>()
         val wasmExpressionGenerator = WasmIrExpressionBuilder(initBody)
-        generateDefaultInitializerForType(wasmType, wasmExpressionGenerator)
+
+        val initValue: IrExpression? = declaration.initializer?.expression
+        if (initValue != null) {
+            check(initValue is IrConst<*> && initValue.kind !is IrConstKind.String && initValue.kind !is IrConstKind.Null) {
+                "Static field initializer should be non-string const or null"
+            }
+            generateConstExpression(initValue, wasmExpressionGenerator, context)
+        } else {
+            generateDefaultInitializerForType(wasmType, wasmExpressionGenerator)
+        }
 
         val global = WasmGlobal(
             name = declaration.fqNameWhenAvailable.toString(),
             type = wasmType,
             isMutable = true,
-            // All globals are currently initialized in start function
             init = initBody
         )
 
@@ -396,4 +407,25 @@ fun IrFunction.getEffectiveValueParameters(): List<IrValueParameter> {
 }
 
 fun IrFunction.isExported(): Boolean =
-    isJsExport()
+    isJsExport()
+
+
+fun generateConstExpression(expression: IrConst<*>, body: WasmExpressionBuilder, context: WasmBaseCodegenContext) {
+    when (val kind = expression.kind) {
+        is IrConstKind.Null -> generateDefaultInitializerForType(context.transformType(expression.type), body)
+        is IrConstKind.Boolean -> body.buildConstI32(if (kind.valueOf(expression)) 1 else 0)
+        is IrConstKind.Byte -> body.buildConstI32(kind.valueOf(expression).toInt())
+        is IrConstKind.Short -> body.buildConstI32(kind.valueOf(expression).toInt())
+        is IrConstKind.Int -> body.buildConstI32(kind.valueOf(expression))
+        is IrConstKind.Long -> body.buildConstI64(kind.valueOf(expression))
+        is IrConstKind.Char -> body.buildConstI32(kind.valueOf(expression).code)
+        is IrConstKind.Float -> body.buildConstF32(kind.valueOf(expression))
+        is IrConstKind.Double -> body.buildConstF64(kind.valueOf(expression))
+        is IrConstKind.String -> {
+            body.buildConstI32Symbol(context.referenceStringLiteral(kind.valueOf(expression)))
+            body.buildConstI32(kind.valueOf(expression).length)
+            body.buildCall(context.referenceFunction(context.backendContext.wasmSymbols.stringGetLiteral))
+        }
+        else -> error("Unknown constant kind")
+    }
+}

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/lower/FieldInitializersLowering.kt

@@ -9,11 +9,14 @@ import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.lower.at
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.wasm.WasmBackendContext
+import org.jetbrains.kotlin.backend.wasm.ir2wasm.getRuntimeClass
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.irSetField
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
+import org.jetbrains.kotlin.ir.expressions.IrConst
+import org.jetbrains.kotlin.ir.expressions.IrConstKind
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
@@ -45,6 +48,8 @@ class FieldInitializersLowering(val context: WasmBackendContext) : FileLoweringP
 
                 if (!declaration.isStatic) return
                 val initValue: IrExpression = declaration.initializer?.expression ?: return
+                // Constant primitive initializers without implicit casting can be processed by native wasm initializers
+                if (initValue.type == declaration.type && initValue is IrConst<*> && initValue.kind !is IrConstKind.String && initValue.kind !is IrConstKind.Null) return
 
                 startFunctionBody.statements.add(
                     builder.at(initValue).irSetField(null, declaration, initValue)