Change illegal local variable mangling rules

compiler/backend/src/org/jetbrains/kotlin/codegen/VariableAsmNameManglingUtils.kt

@@ -25,7 +25,6 @@ fun getNameForDestructuredParameterOrNull(valueParameterDescriptor: ValueParamet
     }
 }
 
-
 fun mangleNameIfNeeded(name: String): String {
     if (name.all { it.isValidCharacter() }) {
         return name
@@ -35,14 +34,23 @@ fun mangleNameIfNeeded(name: String): String {
         for (c in name) {
             if (c.isValidCharacter()) {
                 append(c)
-                continue
+            } else {
+                append('-').append(c.toHex())
             }
-
-            append("_u").append(Integer.toHexString(c.toInt()))
         }
     }
 }
 
+private fun Char.toHex(): String {
+    val hexString = Integer.toHexString(this.toInt())
+    assert(hexString.length <= 4)
+    return if (hexString.length == 4) {
+        hexString
+    } else {
+        "0".repeat(4 - hexString.length) + hexString
+    }
+}
+
 private fun Char.isValidCharacter(): Boolean {
     return this != '$' && this != '-' && isValidDalvikCharacter(this)
 }

compiler/testData/codegen/asmLike/receiverMangling/mangledNames.txt

@@ -101,10 +101,10 @@ final class MangledNamesKt$foo$1 : kotlin/jvm/internal/Lambda, kotlin/jvm/functi
 
     public java.lang.Object invoke(java.lang.Object p0)
 
-    public final void invoke(Arr $dstr$a_u20b$b_u24c$c_u2dd$b_u24_u24c_u2d_u2dd$a_u28_u29§_u26_u2a_u26_u5e_u40あ化) {
+    public final void invoke(Arr $dstr$a-0020b$b-0024c$c-002dd$b-0024-0024c-002d-002dd$a-0028-0029§-0026-002a-0026-005e-0040あ化) {
         Local variables:
             0 this: LMangledNamesKt$foo$1;
-            1 $dstr$a_u20b$b_u24c$c_u2dd$b_u24_u24c_u2d_u2dd$a_u28_u29§_u26_u2a_u26_u5e_u40あ化: LArr;
+            1 $dstr$a-0020b$b-0024c$c-002dd$b-0024-0024c-002d-002dd$a-0028-0029§-0026-002a-0026-005e-0040あ化: LArr;
             2 a b: I
             3 b$c: I
             4 c-d: I