Propagate header compilation flag configuration on the relevant parts of the compiler.

Author: maxmg-jake

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/pipeline/web/WebFrontendPipelinePhase.kt

@@ -193,7 +193,13 @@ object WebFrontendPipelinePhase : PipelinePhase<ConfigurationPipelineArtifact, W
             isCommonSource = { groupedSources.isCommonSourceForLt(it) },
             fileBelongsToModule = { file, it -> groupedSources.fileBelongsToModuleForLt(file, it) },
             buildResolveAndCheckFir = { session, files ->
-                buildResolveAndCheckFirViaLightTree(session, files, diagnosticsReporter, performanceManager?.let { it::addSourcesStats })
+                buildResolveAndCheckFirViaLightTree(
+                    session,
+                    files,
+                    diagnosticsReporter,
+                    performanceManager?.let { it::addSourcesStats },
+                    false
+                )
             },
             useWasmPlatform = useWasmPlatform,
         )

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/legacy/pipeline/jvmIncrementalCompilerPipelineLightTree.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.cli.common.prepareJvmSessions
 import org.jetbrains.kotlin.cli.jvm.compiler.VfsBasedProjectEnvironment
 import org.jetbrains.kotlin.config.CompilerConfiguration
+import org.jetbrains.kotlin.config.headerCompilation
 import org.jetbrains.kotlin.diagnostics.impl.BaseDiagnosticsCollector
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrar
 import org.jetbrains.kotlin.fir.pipeline.FirResult
@@ -94,9 +95,9 @@ private fun FrontendContext.compileModuleToAnalyzedFirViaLightTreeIncrementally(
         )
 
         val countFilesAndLines = if (performanceManager == null) null else performanceManager::addSourcesStats
-
         val outputs = sessionsWithSources.map { (session, sources) ->
-            buildResolveAndCheckFirViaLightTree(session, sources, diagnosticsReporter, countFilesAndLines)
+            buildResolveAndCheckFirViaLightTree(session, sources, diagnosticsReporter, countFilesAndLines,
+                configuration.headerCompilation)
         }
         outputs.runPlatformCheckers(diagnosticsReporter)
         FirResult(outputs)

compiler/cli/src/org/jetbrains/kotlin/cli/pipeline/jvm/JvmFrontendPipelinePhase.kt

@@ -159,7 +159,8 @@ object JvmFrontendPipelinePhase : PipelinePhase<ConfigurationPipelineArtifact, J
         val countFilesAndLines = if (perfManager == null) null else perfManager::addSourcesStats
         val outputs = sessionsWithSources.map { (session, sources) ->
             val rawFirFiles = when (configuration.useLightTree) {
-                true -> session.buildFirViaLightTree(sources, diagnosticsCollector, countFilesAndLines)
+                true -> session.buildFirViaLightTree(sources, diagnosticsCollector, countFilesAndLines,
+                    configuration.headerCompilation)
                 else -> session.buildFirFromKtFiles(sources.asKtFilesList())
             }
             resolveAndCheckFir(session, rawFirFiles, diagnosticsCollector)

compiler/cli/src/org/jetbrains/kotlin/cli/pipeline/metadata/MetadataFrontendPipelinePhase.kt

@@ -32,6 +32,7 @@ import org.jetbrains.kotlin.cli.pipeline.PerformanceNotifications
 import org.jetbrains.kotlin.cli.pipeline.PipelinePhase
 import org.jetbrains.kotlin.cli.pipeline.jvm.asKtFilesList
 import org.jetbrains.kotlin.config.CommonConfigurationKeys
+import org.jetbrains.kotlin.config.headerCompilation
 import org.jetbrains.kotlin.config.messageCollector
 import org.jetbrains.kotlin.config.moduleName
 import org.jetbrains.kotlin.config.useLightTree
@@ -109,9 +110,10 @@ object MetadataFrontendPipelinePhase : PipelinePhase<ConfigurationPipelineArtifa
                 }
             )
             sessionsWithSources.map { (session, files) ->
-                val firFiles = session.buildFirViaLightTree(files, diagnosticsReporter) { files, lines ->
-                    perfManager?.addSourcesStats(files, lines)
-                }
+                val firFiles = session.buildFirViaLightTree(files, diagnosticsReporter, { files, lines ->
+                        perfManager?.addSourcesStats(files, lines)
+                    },
+                    configuration.headerCompilation)
                 resolveAndCheckFir(session, firFiles, diagnosticsReporter)
             }
         } else {

compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/pipeline/firUtils.kt

@@ -24,10 +24,11 @@ fun FirSession.buildFirViaLightTree(
     files: Collection<KtSourceFile>,
     diagnosticsReporter: DiagnosticReporter?,
     reportFilesAndLines: ((Int, Int) -> Unit)?,
+    useHeaderCompilation: Boolean,
 ): List<FirFile> {
     val firProvider = (firProvider as FirProviderImpl)
     val sourcesToPathsMapper = sourcesToPathsMapper
-    val builder = LightTree2Fir(this, firProvider.kotlinScopeProvider, diagnosticsReporter)
+    val builder = LightTree2Fir(this, useHeaderCompilation,firProvider.kotlinScopeProvider, diagnosticsReporter)
     val shouldCountLines = (reportFilesAndLines != null)
     var linesCount = 0
     val firFiles = files.map { file ->
@@ -82,8 +83,9 @@ fun buildResolveAndCheckFirViaLightTree(
     session: FirSession,
     ktFiles: Collection<KtSourceFile>,
     diagnosticsReporter: BaseDiagnosticsCollector,
-    countFilesAndLines: KFunction2<Int, Int, Unit>?
+    countFilesAndLines: KFunction2<Int, Int, Unit>?,
+    useHeaderCompilation: Boolean,
 ): ModuleCompilerAnalyzedOutput {
-    val firFiles = session.buildFirViaLightTree(ktFiles, diagnosticsReporter, countFilesAndLines)
+    val firFiles = session.buildFirViaLightTree(ktFiles, diagnosticsReporter, countFilesAndLines, useHeaderCompilation)
     return resolveAndCheckFir(session, firFiles, diagnosticsReporter)
 }

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/LightTree2Fir.kt

@@ -23,6 +23,7 @@ import java.nio.file.Path
 
 class LightTree2Fir(
     val session: FirSession,
+    val headerCompilationMode: Boolean,
     private val scopeProvider: FirScopeProvider,
     private val diagnosticsReporter: DiagnosticReporter? = null,
 ) {
@@ -43,7 +44,7 @@ class LightTree2Fir(
         sourceFile: KtSourceFile,
         linesMapping: KtSourceFileLinesMapping,
     ): FirFile {
-        return LightTreeRawFirDeclarationBuilder(session, scopeProvider, lightTree)
+        return LightTreeRawFirDeclarationBuilder(session, scopeProvider, lightTree, headerCompilationMode)
             .convertFile(lightTree.root, sourceFile, linesMapping)
     }
 

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirDeclarationBuilder.kt

@@ -61,10 +61,10 @@ class LightTreeRawFirDeclarationBuilder(
     session: FirSession,
     internal val baseScopeProvider: FirScopeProvider,
     tree: FlyweightCapableTreeStructure<LighterASTNode>,
+    private val headerCompilationMode: Boolean = false,
     context: Context<LighterASTNode> = Context(),
 ) : AbstractLightTreeRawFirBuilder(session, tree, context) {
-
-    private val expressionConverter = LightTreeRawFirExpressionBuilder(session, tree, this, context)
+    private val expressionConverter = LightTreeRawFirExpressionBuilder(session, tree, this, headerCompilationMode, context)
 
     /**
      * [org.jetbrains.kotlin.parsing.KotlinParsing.parseFile]
@@ -1238,6 +1238,7 @@ class LightTreeRawFirDeclarationBuilder(
                 modifiers?.convertAnnotationsTo(annotations)
                 typeParameters += constructorTypeParametersFromConstructedClass(classWrapper.classBuilder.typeParameters)
                 valueParameters += firValueParameters.map { it.firValueParameter }
+                // TODO-HEADER-COMPILATION: Potentially remove this and produce an empty constructor body.
                 val (body, contractDescription) = withForcedLocalContext {
                     convertFunctionBody(block, null, allowLegacyContractDescription = true)
                 }
@@ -1735,6 +1736,7 @@ class LightTreeRawFirDeclarationBuilder(
                 valueParameters += firValueParameters
             }
             val allowLegacyContractDescription = outerContractDescription == null
+            // TODO-HEADER-COMPILATION: Potentially remove getter/setter code.
             val bodyWithContractDescription = withForcedLocalContext {
                 convertFunctionBody(block, expression, allowLegacyContractDescription)
             }
@@ -2080,6 +2082,8 @@ class LightTreeRawFirDeclarationBuilder(
         expression: LighterASTNode?,
         allowLegacyContractDescription: Boolean
     ): Pair<FirBlock?, FirContractDescription?> {
+        // TODO-HEADER-COMPILATION: Another option to produce empty methods
+        // TODO-HEADER-COMPILATION: is to make this function return nothing.
         return when {
             blockNode != null -> {
                 val block = convertBlock(blockNode)
@@ -2115,6 +2119,8 @@ class LightTreeRawFirDeclarationBuilder(
      * @see org.jetbrains.kotlin.parsing.KotlinParsing.parseBlock
      */
     fun convertBlock(block: LighterASTNode?): FirBlock {
+        // TODO-HEADER-COMPILATION: One option is to prevent the frontend
+        // TODO-HEADER-COMPILATION: from producing IR here.
         if (block == null) return buildEmptyExpressionBlock()
         if (block.tokenType != BLOCK) {
             return FirSingleExpressionBlock(

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/LightTreeRawFirExpressionBuilder.kt

@@ -62,6 +62,7 @@ class LightTreeRawFirExpressionBuilder(
     session: FirSession,
     tree: FlyweightCapableTreeStructure<LighterASTNode>,
     private val declarationBuilder: LightTreeRawFirDeclarationBuilder,
+    val headerCompilationMode: Boolean = false, // TODO: may be unnecessary
     context: Context<LighterASTNode> = Context(),
 ) : AbstractLightTreeRawFirBuilder(session, tree, context) {