JS PIR: move PIR proto messages to a separate file

compiler/ir/ir.tree.persistent/generator/src/org/jetbrains/kotlin/ir/persistentIrGenerator/Main.kt

@@ -20,7 +20,7 @@ fun main() {
         generateTypeParameter()
         generateValueParameter()
 
-        updateKotlinIrProto()
+        generateKotlinPirCarriersProto()
         generateCarrierDeserializer()
         generateCarrierSerializer()
     }

compiler/ir/ir.tree.persistent/generator/src/org/jetbrains/kotlin/ir/persistentIrGenerator/PersistentIrGenerator.kt

@@ -661,27 +661,27 @@ internal object PersistentIrGenerator {
         File(prefix + path).writeText(content)
     }
 
-    fun updateKotlinIrProto() {
-        val file = File("compiler/ir/serialization.common/src/KotlinIr.proto")
+    fun generateKotlinPirCarriersProto() {
+        val file = File("compiler/ir/serialization.common/src/KotlinPirCarriers.proto")
 
-        if (!file.exists()) throw IllegalStateException("KotlinIr.proto file not found!")
+        val sb = StringBuilder("""
+            syntax = "proto2";
+            package org.jetbrains.kotlin.backend.common.serialization.proto;
 
-        val lines = file.readText().lines()
+            option java_multiple_files = true;
+            option java_outer_classname = "KotlinIr";
+            option optimize_for = LITE_RUNTIME;
 
-        val start = lines.indexOf("// PIR GENERATOR START")
-        if (start < 0) throw IllegalStateException("Couldn't find the '// PIR GENERATOR START' line. Don't know where to write generated messages.")
-
-        val end = lines.indexOf("// PIR GENERATOR END")
-        if (end < 0) throw IllegalStateException("Couldn't find the '// PIR GENERATOR END' line. Don't know where to write generated messages.")
-
-        val sb = StringBuilder(lines.subList(0, start + 1).joinToString(separator = "\n"))
+            import "compiler/ir/serialization.common/src/KotlinIr.proto";
+            
+            // Auto-generated by compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/persistentIrGenerator/Main.kt. DO NOT EDIT!
+            
+        """.trimIndent())
 
         for (m in protoMessages) {
             sb.append("\n").append(m)
         }
 
-        sb.append("\n").append(lines.subList(end, lines.size).joinToString(separator = "\n"))
-
         file.writeText(sb.toString())
     }