[FIR] Introduce FirAnalyzerFacade which hides implementation details of running FIR compiler

compiler/fir/entrypoint/build.gradle.kts

@@ -7,9 +7,16 @@ dependencies {
     api(project(":core:descriptors.jvm"))
     api(project(":compiler:frontend.java"))
     api(project(":compiler:fir:java"))
+    api(project(":compiler:fir:raw-fir:psi2fir"))
+    api(project(":compiler:fir:fir2ir"))
+    api(project(":compiler:fir:checkers"))
 
     implementation(project(":compiler:fir:resolve"))
-    implementation(project(":compiler:fir:checkers"))
+    implementation(project(":compiler:fir:fir2ir:jvm-backend"))
+    implementation(project(":compiler:backend.jvm"))
+    implementation(project(":compiler:ir.serialization.common"))
+    implementation(project(":compiler:ir.serialization.jvm"))
+    implementation(project(":compiler:ir.tree.impl"))
 
     compileOnly(project(":kotlin-reflect-api"))
     compileOnly(intellijCoreDep()) { includeJars("intellij-core", "guava", rootProject = rootProject) }

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

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis
+
+import org.jetbrains.kotlin.backend.common.serialization.signature.IdSignatureDescriptor
+import org.jetbrains.kotlin.backend.jvm.JvmGeneratorExtensions
+import org.jetbrains.kotlin.config.LanguageVersionSettings
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.analysis.collectors.FirDiagnosticsCollector
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnostic
+import org.jetbrains.kotlin.fir.backend.Fir2IrConverter
+import org.jetbrains.kotlin.fir.backend.Fir2IrResult
+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.resolve.ScopeSession
+import org.jetbrains.kotlin.fir.resolve.firProvider
+import org.jetbrains.kotlin.fir.resolve.providers.impl.FirProviderImpl
+import org.jetbrains.kotlin.fir.resolve.transformers.FirTotalResolveProcessor
+import org.jetbrains.kotlin.ir.backend.jvm.serialization.JvmManglerDesc
+import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
+import org.jetbrains.kotlin.psi.KtFile
+
+class FirAnalyzerFacade(val session: FirSession, val languageVersionSettings: LanguageVersionSettings, val ktFiles: List<KtFile>) {
+    private var firFiles: List<FirFile>? = null
+    private var scopeSession: ScopeSession? = null
+    private var collectedDiagnostics: List<FirDiagnostic<*>>? = null
+
+    private fun buildRawFir() {
+        if (firFiles != null) return
+        val firProvider = (session.firProvider as FirProviderImpl)
+        val builder = RawFirBuilder(session, firProvider.kotlinScopeProvider, stubMode = false)
+        firFiles = ktFiles.map {
+            val firFile = builder.buildFirFile(it)
+            firProvider.recordFile(firFile)
+            firFile
+        }
+    }
+
+    fun runResolution(): List<FirFile> {
+        if (firFiles == null) buildRawFir()
+        if (scopeSession != null) return firFiles!!
+        val resolveProcessor = FirTotalResolveProcessor(session)
+        resolveProcessor.process(firFiles!!)
+        scopeSession = resolveProcessor.scopeSession
+        return firFiles!!
+    }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    fun runCheckers(): List<FirDiagnostic<*>> {
+        if (scopeSession == null) runResolution()
+        if (collectedDiagnostics != null) return collectedDiagnostics!!
+        val collector = FirDiagnosticsCollector.create(session)
+        collectedDiagnostics = buildList {
+            for (file in firFiles!!) {
+                addAll(collector.collectDiagnostics(file))
+            }
+        }
+        return collectedDiagnostics!!
+    }
+
+    fun convertToIr(): Fir2IrResult {
+        if (scopeSession == null) runResolution()
+        val signaturer = IdSignatureDescriptor(JvmManglerDesc())
+
+        return Fir2IrConverter.createModuleFragment(
+            session, scopeSession!!, firFiles!!,
+            languageVersionSettings, signaturer,
+            JvmGeneratorExtensions(), FirJvmKotlinMangler(session), IrFactoryImpl,
+            FirJvmVisibilityConverter
+        )
+    }
+}