Avoid reparsing C headers in cinterop whenever possible (#3082)

Thus optimize it.

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Indexer.kt

@@ -947,18 +947,23 @@ internal class NativeIndexImpl(val library: NativeLibrary, val verbose: Boolean
 
 }
 
-fun buildNativeIndexImpl(library: NativeLibrary, verbose: Boolean): NativeIndex {
+fun buildNativeIndexImpl(library: NativeLibrary, verbose: Boolean): IndexerResult {
     val result = NativeIndexImpl(library, verbose)
-    indexDeclarations(result)
-    return result
+    val compilation = indexDeclarations(result)
+    return IndexerResult(result, compilation)
 }
 
-private fun indexDeclarations(nativeIndex: NativeIndexImpl) {
+private fun indexDeclarations(nativeIndex: NativeIndexImpl): CompilationWithPCH {
     withIndex { index ->
-        val translationUnit = nativeIndex.library.parse(index, options = CXTranslationUnit_DetailedPreprocessingRecord)
+        val translationUnit = nativeIndex.library.parse(
+                index,
+                options = CXTranslationUnit_DetailedPreprocessingRecord or CXTranslationUnit_ForSerialization
+        )
         try {
             translationUnit.ensureNoCompileErrors()
 
+            val compilation = nativeIndex.library.withPrecompiledHeader(translationUnit)
+
             val headers = getFilteredHeaders(nativeIndex, index, translationUnit)
 
             nativeIndex.includedHeaders = headers.map {
@@ -991,7 +996,9 @@ private fun indexDeclarations(nativeIndex: NativeIndexImpl) {
                 CXChildVisitResult.CXChildVisit_Continue
             }
 
-            findMacros(nativeIndex, translationUnit, headers)
+            findMacros(nativeIndex, compilation, translationUnit, headers)
+
+            return compilation
         } finally {
             clang_disposeTranslationUnit(translationUnit)
         }

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/MacroConstants.kt

@@ -23,10 +23,15 @@ import java.io.File
 /**
  * Finds all "macro constants" and registers them as [NativeIndex.constants] in given index.
  */
-internal fun findMacros(nativeIndex: NativeIndexImpl, translationUnit: CXTranslationUnit, headers: Set<CXFile?>) {
+internal fun findMacros(
+        nativeIndex: NativeIndexImpl,
+        compilation: CompilationWithPCH,
+        translationUnit: CXTranslationUnit,
+        headers: Set<CXFile?>
+) {
     val names = collectMacroNames(nativeIndex, translationUnit, headers)
     // TODO: apply user-defined filters.
-    val macros = expandMacros(nativeIndex.library, names, typeConverter = { nativeIndex.convertType(it) })
+    val macros = expandMacros(compilation, names, typeConverter = { nativeIndex.convertType(it) })
 
     macros.filterIsInstanceTo(nativeIndex.macroConstants)
     macros.filterIsInstanceTo(nativeIndex.wrappedMacros)
@@ -38,18 +43,16 @@ private typealias TypeConverter = (CValue<CXType>) -> Type
  * For each name expands the macro with this name declared in the library,
  * checking if it gets expanded to a constant expression.
  *
+ * Note: in the worst case this method parses the code against the library a lot of times,
+ * so it requires library headers precompiled to significantly speed up the parsing and avoid visiting headers' AST.
+ *
  * @return the list of constants.
  */
 private fun expandMacros(
-        originalLibrary: NativeLibrary,
+        library: CompilationWithPCH,
         names: List<String>,
         typeConverter: TypeConverter
 ): List<MacroDef> {
-
-    // In the worst case code is parsed against the library a lot of times;
-    // so precompile library headers to significantly speed up the parsing and avoid visiting headers' AST:
-    val library = originalLibrary.precompileHeaders()
-
     withIndex(excludeDeclarationsFromPCH = true) { index ->
         val sourceFile = library.createTempSource()
         val compilerArgs = library.compilerArgs.toMutableList()
@@ -94,7 +97,7 @@ private fun expandMacros(
  * As a side effect, modifies the [sourceFile] and reparses the [translationUnit].
  */
 private fun tryExpandMacros(
-        library: NativeLibrary,
+        library: CompilationWithPCH,
         translationUnit: CXTranslationUnit,
         sourceFile: File,
         names: List<String>,
@@ -158,7 +161,7 @@ private const val CODE_SNIPPET_FUNCTION_NAME_PREFIX = "kni_indexer_function_"
  * generate a bridge for this macro.
  *  - Otherwise the macro is skipped.
  */
-private fun reparseWithCodeSnippets(library: NativeLibrary,
+private fun reparseWithCodeSnippets(library: CompilationWithPCH,
                                     translationUnit: CXTranslationUnit, sourceFile: File,
                                     names: List<String>) {
 

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/ModuleSupport.kt

@@ -53,9 +53,9 @@ internal open class ModularCompilation(compilation: Compilation): Compilation by
 }
 
 private fun getModulesASTFiles(index: CXIndex, compilation: ModularCompilation, modules: List<String>): List<String> {
-    val compilationWithImports = object : Compilation by compilation {
-        override val additionalPreambleLines = modules.map { "@import $it;" } + compilation.additionalPreambleLines
-    }
+    val compilationWithImports = compilation.copy(
+            additionalPreambleLines = modules.map { "@import $it;" } + compilation.additionalPreambleLines
+    )
 
     val result = linkedSetOf<String>()
 

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/NativeIndex.kt

@@ -57,7 +57,22 @@ interface Compilation {
     val language: Language
 }
 
-// TODO: consider replacing inheritance by composition and turning Compilation into final class.
+data class CompilationWithPCH(
+        override val compilerArgs: List<String>,
+        override val language: Language
+) : Compilation {
+
+    constructor(compilerArgs: List<String>, precompiledHeader: String, language: Language)
+            : this(compilerArgs + listOf("-include-pch", precompiledHeader), language)
+
+    override val includes: List<String>
+        get() = emptyList()
+
+    override val additionalPreambleLines: List<String>
+        get() = emptyList()
+}
+
+// TODO: Compilation hierarchy seems to require some refactoring.
 
 data class NativeLibrary(override val includes: List<String>,
                          override val additionalPreambleLines: List<String>,
@@ -68,10 +83,12 @@ data class NativeLibrary(override val includes: List<String>,
                          val headerExclusionPolicy: HeaderExclusionPolicy,
                          val headerFilter: NativeLibraryHeaderFilter) : Compilation
 
+data class IndexerResult(val index: NativeIndex, val compilation: CompilationWithPCH)
+
 /**
  * Retrieves the definitions from given C header file using given compiler arguments (e.g. defines).
  */
-fun buildNativeIndex(library: NativeLibrary, verbose: Boolean): NativeIndex = buildNativeIndexImpl(library, verbose)
+fun buildNativeIndex(library: NativeLibrary, verbose: Boolean): IndexerResult = buildNativeIndexImpl(library, verbose)
 
 /**
  * This class describes the IR of definitions from C header file(s).

Interop/Indexer/src/main/kotlin/org/jetbrains/kotlin/native/interop/indexer/Utils.kt

@@ -241,30 +241,46 @@ internal fun Compilation.createTempSource(): File {
     return result
 }
 
+fun Compilation.copy(
+        includes: List<String> = this.includes,
+        additionalPreambleLines: List<String> = this.additionalPreambleLines,
+        compilerArgs: List<String> = this.compilerArgs,
+        language: Language = this.language
+): Compilation = CompilationImpl(
+        includes = includes,
+        additionalPreambleLines = additionalPreambleLines,
+        compilerArgs = compilerArgs,
+        language = language
+)
+
+data class CompilationImpl(
+        override val includes: List<String>,
+        override val additionalPreambleLines: List<String>,
+        override val compilerArgs: List<String>,
+        override val language: Language
+) : Compilation
+
 /**
  * Precompiles the headers of this library.
  *
  * @return the library which includes the precompiled header instead of original ones.
  */
-internal fun NativeLibrary.precompileHeaders(): NativeLibrary {
-    val precompiledHeader = createTempFile(suffix = ".pch").apply { this.deleteOnExit() }
-
-    withIndex { index ->
-        val options = CXTranslationUnit_ForSerialization
-        val translationUnit = this.parse(index, options)
-        try {
-            translationUnit.ensureNoCompileErrors()
-            clang_saveTranslationUnit(translationUnit, precompiledHeader.absolutePath, 0)
-        } finally {
-            clang_disposeTranslationUnit(translationUnit)
-        }
+fun Compilation.precompileHeaders(): CompilationWithPCH = withIndex { index ->
+    val options = CXTranslationUnit_ForSerialization
+    val translationUnit = this.parse(index, options)
+    try {
+        translationUnit.ensureNoCompileErrors()
+        withPrecompiledHeader(translationUnit)
+    } finally {
+        clang_disposeTranslationUnit(translationUnit)
     }
+}
 
-    return this.copy(
-            includes = emptyList(),
-            additionalPreambleLines = emptyList(),
-            compilerArgs = this.compilerArgs + listOf("-include-pch", precompiledHeader.absolutePath)
-    )
+internal fun Compilation.withPrecompiledHeader(translationUnit: CXTranslationUnit): CompilationWithPCH {
+    val precompiledHeader = createTempFile(suffix = ".pch").apply { this.deleteOnExit() }
+    clang_saveTranslationUnit(translationUnit, precompiledHeader.absolutePath, 0)
+
+    return CompilationWithPCH(this.compilerArgs, precompiledHeader.absolutePath, this.language)
 }
 
 internal fun NativeLibrary.includesDeclaration(cursor: CValue<CXCursor>): Boolean {
@@ -289,10 +305,9 @@ internal fun CXTranslationUnit.getErrorLineNumbers(): Sequence<Int> =
 /**
  * For each list of lines, checks if the code fragment composed from these lines is compilable against given library.
  */
-fun List<List<String>>.mapFragmentIsCompilable(originalLibrary: NativeLibrary): List<Boolean> {
-    val library = originalLibrary
+fun List<List<String>>.mapFragmentIsCompilable(originalLibrary: CompilationWithPCH): List<Boolean> {
+    val library: CompilationWithPCH = originalLibrary
             .copy(compilerArgs = originalLibrary.compilerArgs + "-ferror-limit=0")
-            .precompileHeaders()
 
     val indicesOfNonCompilable = mutableSetOf<Int>()
 

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/SimpleBridgeGeneratorImpl.kt

@@ -17,15 +17,15 @@
 package org.jetbrains.kotlin.native.interop.gen
 
 import org.jetbrains.kotlin.native.interop.gen.jvm.KotlinPlatform
+import org.jetbrains.kotlin.native.interop.indexer.CompilationWithPCH
 import org.jetbrains.kotlin.native.interop.indexer.Language
-import org.jetbrains.kotlin.native.interop.indexer.NativeLibrary
 import org.jetbrains.kotlin.native.interop.indexer.mapFragmentIsCompilable
 
 class SimpleBridgeGeneratorImpl(
         private val platform: KotlinPlatform,
         private val pkgName: String,
         private val jvmFileClassName: String,
-        private val libraryForCStubs: NativeLibrary,
+        private val libraryForCStubs: CompilationWithPCH,
         override val topLevelNativeScope: NativeScope,
         private val topLevelKotlinScope: KotlinScope
 ) : SimpleBridgeGenerator {

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/InteropConfiguration.kt

@@ -17,13 +17,13 @@
 package org.jetbrains.kotlin.native.interop.gen.jvm
 
 import org.jetbrains.kotlin.konan.target.KonanTarget
-import org.jetbrains.kotlin.native.interop.indexer.NativeLibrary
+import org.jetbrains.kotlin.native.interop.indexer.CompilationWithPCH
 
 /**
  * Describes the native library and the options for adjusting the Kotlin API to be generated for this library.
  */
 class InteropConfiguration(
-        val library: NativeLibrary,
+        val library: CompilationWithPCH,
         val pkgName: String,
         val excludedFunctions: Set<String>,
         val excludedMacros: Set<String>,

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt

@@ -965,7 +965,7 @@ class StubGenerator(
                         Language.C -> emptyList()
                         Language.OBJECTIVE_C -> listOf("void objc_terminate();")
                     }
-    )
+    ).precompileHeaders()
 
     /**
      * Produces to [out] the contents of C source file to be compiled into native lib used for Kotlin bindings impl.

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/main.kt

@@ -220,8 +220,10 @@ private fun processCLib(args: Array<String>, additionalArgs: Map<String, Any> =
 
     val library = buildNativeLibrary(tool, def, argParser, imports)
 
+    val (nativeIndex, compilation) = buildNativeIndex(library, verbose)
+
     val configuration = InteropConfiguration(
-            library = library,
+            library = compilation,
             pkgName = outKtPkg,
             excludedFunctions = excludedFunctions,
             excludedMacros = excludedMacros,
@@ -233,8 +235,6 @@ private fun processCLib(args: Array<String>, additionalArgs: Map<String, Any> =
             target = tool.target
     )
 
-    val nativeIndex = buildNativeIndex(library, verbose)
-
     val gen = StubGenerator(nativeIndex, configuration, libName, verbose, flavor, imports)
 
     outKtFile.parentFile.mkdirs()
@@ -330,12 +330,12 @@ internal fun buildNativeLibrary(
         })
     }
 
-    val compilation = object : Compilation {
-        override val includes = headerFiles
-        override val additionalPreambleLines = def.defHeaderLines
-        override val compilerArgs = compilerOpts + tool.platformCompilerOpts
-        override val language = language
-    }
+    val compilation = CompilationImpl(
+            includes = headerFiles,
+            additionalPreambleLines = def.defHeaderLines,
+            compilerArgs = compilerOpts + tool.platformCompilerOpts,
+            language = language
+    )
 
     val headerFilter: NativeLibraryHeaderFilter
     val includes: List<String>