[Wasm] Disable range checks for arrays. Add cli argument to enable them back.

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.kt

@@ -253,6 +253,9 @@ class K2JSCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "-Xwasm-kclass-fqn", description = "Enable support for FQ names in KClass")
     var wasmKClassFqn: Boolean by FreezableVar(false)
 
+    @Argument(value = "-Xwasm-enable-array-range-checks", description = "Turn on range checks for the array access functions")
+    var wasmEnableArrayRangeChecks: Boolean by FreezableVar(false)
+
     override fun configureAnalysisFlags(collector: MessageCollector, languageVersion: LanguageVersion): MutableMap<AnalysisFlag<*>, Any> {
         return super.configureAnalysisFlags(collector, languageVersion).also {
             it[allowFullyQualifiedNameInKClass] = wasm && wasmKClassFqn //Only enabled WASM BE supports this flag

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -135,6 +135,8 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
 
         configuration.put(JSConfigurationKeys.PARTIAL_LINKAGE, arguments.partialLinkage)
 
+        configuration.put(JSConfigurationKeys.WASM_ENABLE_ARRAY_RANGE_CHECKS, arguments.wasmEnableArrayRangeChecks)
+
         val commonSourcesArray = arguments.commonSources
         val commonSources = commonSourcesArray?.toSet() ?: emptySet()
         for (arg in arguments.freeArgs) {

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmSymbols.kt

@@ -156,6 +156,8 @@ class WasmSymbols(
 
     val wasmRefCast = getInternalFunction("wasm_ref_cast")
 
+    val rangeCheck = getInternalFunction("rangeCheck")
+
     val boxIntrinsic: IrSimpleFunctionSymbol = getInternalFunction("boxIntrinsic")
     val unboxIntrinsic: IrSimpleFunctionSymbol = getInternalFunction("unboxIntrinsic")
 

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

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.ir.util.isInterface
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
+import org.jetbrains.kotlin.js.config.JSConfigurationKeys
 import org.jetbrains.kotlin.wasm.ir.*
 
 class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorVoid {
@@ -258,6 +259,13 @@ class BodyGenerator(val context: WasmFunctionCodegenContext) : IrElementVisitorV
             return
         }
 
+        // Range check intrinsic is a special case because it doesn't require arguments on the stack.
+        if (call.symbol == wasmSymbols.rangeCheck &&
+            backendContext.configuration.getNotNull(JSConfigurationKeys.WASM_ENABLE_ARRAY_RANGE_CHECKS) == false) {
+            body.buildGetUnit()
+            return
+        }
+
         val function: IrFunction = call.symbol.owner.realOverrideTarget
 
         call.dispatchReceiver?.let { generateExpression(it) }

compiler/testData/cli/js/jsExtraHelp.out

@@ -39,6 +39,8 @@ where advanced options include:
   -Xtyped-arrays             Translate primitive arrays to JS typed arrays
   -Xwasm                     Use experimental WebAssembly compiler backend
   -Xwasm-debug-info          Add debug info to WebAssembly compiled module
+  -Xwasm-enable-array-range-checks
+                             Turn on range checks for the array access functions
   -Xwasm-kclass-fqn          Enable support for FQ names in KClass
   -Xwasm-launcher=esm|nodejs|d8 Picks flavor for the wasm launcher. Default is ESM.
   -Xallow-kotlin-package     Allow compiling code in package 'kotlin' and allow not requiring kotlin.stdlib in module-info