Speed-up looking up modules in JS files. This reduces the time needed for JS backend tests to pass

(cherry picked from commit 951ec82)

js/js.inliner/src/org/jetbrains/kotlin/js/inline/FunctionReader.kt

@@ -43,6 +43,7 @@ import java.io.File
  * Kotlin, _ can be renamed by minifier, quotes type can be changed too (" to ')
  */
 private val DEFINE_MODULE_PATTERN = "(\\w+)\\.defineModule\\(\\s*(['\"])(\\w+)\\2\\s*,\\s*(\\w+)\\s*\\)".toRegex()
+private val DEFINE_MODULE_FIND_PATTERN = ".defineModule("
 
 class FunctionReader(private val context: TranslationContext) {
     /**
@@ -68,12 +69,20 @@ class FunctionReader(private val context: TranslationContext) {
         val libs = config.libraries.map { File(it) }
 
         JsLibraryUtils.traverseJsLibraries(libs) { fileContent, path ->
-            val matcher = DEFINE_MODULE_PATTERN.toPattern().matcher(fileContent)
+            var current = 0
 
-            while (matcher.find()) {
-                val moduleName = matcher.group(3)
-                val moduleVariable = matcher.group(4)
-                val kotlinVariable = matcher.group(1)
+            while (true) {
+                var index = fileContent.indexOf(DEFINE_MODULE_FIND_PATTERN, current)
+                if (index < 0) break
+
+                current = index + 1
+                index = rewindToFirstAlpha(fileContent, index)
+                val preciseMatcher = DEFINE_MODULE_PATTERN.toPattern().matcher(offset(fileContent, index))
+                if (!preciseMatcher.lookingAt()) continue
+
+                val moduleName = preciseMatcher.group(3)
+                val moduleVariable = preciseMatcher.group(4)
+                val kotlinVariable = preciseMatcher.group(1)
                 assert(moduleName !in moduleJsDefinition) { "Module is defined in more, than one file" }
                 moduleJsDefinition[moduleName] = fileContent
                 moduleRootVariable[moduleName] = moduleVariable
@@ -82,6 +91,32 @@ class FunctionReader(private val context: TranslationContext) {
         }
     }
 
+    private fun rewindToFirstAlpha(text: String, index: Int): Int {
+        var result = index
+        while (result > 0 && isAlphaNum(text[result - 1])) {
+            --result
+        }
+        return result
+    }
+
+    private fun offset(text: String, offset: Int) = object : CharSequence {
+        override val length: Int
+            get() = text.length - offset
+
+        override fun get(index: Int) = text[index + offset]
+
+        override fun subSequence(startIndex: Int, endIndex: Int) = text.subSequence(startIndex + offset, endIndex + offset)
+
+        override fun toString() = text.substring(offset)
+    }
+
+    private fun isAlphaNum(c: Char) = when (c) {
+        in 'A'..'Z',
+        in 'a'..'z',
+        in '0'..'9' -> true
+        else -> false
+    }
+
     private val functionCache = object : SLRUCache<CallableDescriptor, JsFunction>(50, 50) {
         override fun createValue(descriptor: CallableDescriptor): JsFunction =
                 readFunction(descriptor).sure { "Could not read function: $descriptor" }