[FIR] Add light tree mode to FirAnalyzerFacade

compiler/fir/entrypoint/build.gradle.kts

@@ -8,6 +8,7 @@ dependencies {
     api(project(":compiler:frontend.java"))
     api(project(":compiler:fir:java"))
     api(project(":compiler:fir:raw-fir:psi2fir"))
+    api(project(":compiler:fir:raw-fir:light-tree2fir"))
     api(project(":compiler:fir:fir2ir"))
     api(project(":compiler:fir:checkers"))
 

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/analysis/FirAnalyzerFacade.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.backend.jvm.FirJvmKotlinMangler
 import org.jetbrains.kotlin.fir.backend.jvm.FirJvmVisibilityConverter
 import org.jetbrains.kotlin.fir.builder.RawFirBuilder
 import org.jetbrains.kotlin.fir.declarations.FirFile
+import org.jetbrains.kotlin.fir.lightTree.LightTree2Fir
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.firProvider
 import org.jetbrains.kotlin.fir.resolve.providers.impl.FirProviderImpl
@@ -25,8 +26,15 @@ import org.jetbrains.kotlin.ir.backend.jvm.serialization.JvmManglerDesc
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi2ir.generators.GeneratorExtensions
+import java.io.File
 
-class FirAnalyzerFacade(val session: FirSession, val languageVersionSettings: LanguageVersionSettings, val ktFiles: Collection<KtFile>) {
+class FirAnalyzerFacade(
+    val session: FirSession,
+    val languageVersionSettings: LanguageVersionSettings,
+    val ktFiles: Collection<KtFile> = emptyList(), // may be empty if light tree mode enabled
+    val originalFiles: Collection<File> = emptyList(), // may be empty if light tree mode disabled
+    val useLightTree: Boolean = false
+) {
     private var firFiles: List<FirFile>? = null
     private var scopeSession: ScopeSession? = null
     private var collectedDiagnostics: Map<FirFile, List<FirDiagnostic<*>>>? = null
@@ -34,11 +42,20 @@ class FirAnalyzerFacade(val session: FirSession, val languageVersionSettings: La
     private fun buildRawFir() {
         if (firFiles != null) return
         val firProvider = (session.firProvider as FirProviderImpl)
-        val builder = RawFirBuilder(session, firProvider.kotlinScopeProvider)
-        firFiles = ktFiles.map {
-            val firFile = builder.buildFirFile(it)
-            firProvider.recordFile(firFile)
-            firFile
+        firFiles = if (useLightTree) {
+            val builder = LightTree2Fir(session, firProvider.kotlinScopeProvider)
+            originalFiles.map {
+                builder.buildFirFile(it).also { firFile ->
+                    firProvider.recordFile(firFile)
+                }
+            }
+        } else {
+            val builder = RawFirBuilder(session, firProvider.kotlinScopeProvider)
+            ktFiles.map {
+                builder.buildFirFile(it).also { firFile ->
+                    firProvider.recordFile(firFile)
+                }
+            }
         }
     }