Don't reparse headers when collecting macro names

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

@@ -913,7 +913,6 @@ internal class NativeIndexImpl(val library: NativeLibrary, val verbose: Boolean
 fun buildNativeIndexImpl(library: NativeLibrary, verbose: Boolean): NativeIndex {
     val result = NativeIndexImpl(library, verbose)
     indexDeclarations(result)
-    findMacros(result)
     return result
 }
 
@@ -955,6 +954,8 @@ private fun indexDeclarations(nativeIndex: NativeIndexImpl) {
                 }
                 CXChildVisitResult.CXChildVisit_Continue
             }
+
+            findMacros(nativeIndex, translationUnit, headers)
         } finally {
             clang_disposeTranslationUnit(translationUnit)
         }

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

@@ -23,8 +23,8 @@ import java.io.File
 /**
  * Finds all "macro constants" and registers them as [NativeIndex.constants] in given index.
  */
-internal fun findMacros(nativeIndex: NativeIndexImpl) {
-    val names = collectMacroNames(nativeIndex)
+internal fun findMacros(nativeIndex: NativeIndexImpl, 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) })
 
@@ -226,42 +226,26 @@ enum class VisitorState {
     EXPECT_END, INVALID
 }
 
-private fun collectMacroNames(nativeIndex: NativeIndexImpl): List<String> {
+private fun collectMacroNames(nativeIndex: NativeIndexImpl, translationUnit: CXTranslationUnit, headers: Set<CXFile?>): List<String> {
     val result = mutableSetOf<String>()
-    val index = clang_createIndex(excludeDeclarationsFromPCH = 0, displayDiagnostics = 0)!!
-    try {
-        // Include macros into AST:
-        val options = CXTranslationUnit_DetailedPreprocessingRecord
 
-        val translationUnit = nativeIndex.library.parse(index, options)
-        try {
-            translationUnit.ensureNoCompileErrors()
-            val headers = getFilteredHeaders(nativeIndex, index, translationUnit)
-
-            visitChildren(translationUnit) { cursor, _ ->
-                val file = memScoped {
-                    val fileVar = alloc<CXFileVar>()
-                    clang_getFileLocation(clang_getCursorLocation(cursor), fileVar.ptr, null, null, null)
-                    fileVar.value
-                }
-
-                if (cursor.kind == CXCursorKind.CXCursor_MacroDefinition &&
-                        nativeIndex.library.includesDeclaration(cursor) &&
-                        file != null && // Builtin macros mostly seem to be useless.
-                        file in headers &&
-                        canMacroBeConstant(cursor))
-                {
-                    val spelling = getCursorSpelling(cursor)
-                    result.add(spelling)
-                }
-                CXChildVisitResult.CXChildVisit_Continue
-            }
-
-        } finally {
-            clang_disposeTranslationUnit(translationUnit)
+    visitChildren(translationUnit) { cursor, _ ->
+        val file = memScoped {
+            val fileVar = alloc<CXFileVar>()
+            clang_getFileLocation(clang_getCursorLocation(cursor), fileVar.ptr, null, null, null)
+            fileVar.value
         }
-    } finally {
-        clang_disposeIndex(index)
+
+        if (cursor.kind == CXCursorKind.CXCursor_MacroDefinition &&
+                nativeIndex.library.includesDeclaration(cursor) &&
+                file != null && // Builtin macros mostly seem to be useless.
+                file in headers &&
+                canMacroBeConstant(cursor))
+        {
+            val spelling = getCursorSpelling(cursor)
+            result.add(spelling)
+        }
+        CXChildVisitResult.CXChildVisit_Continue
     }
 
     return result.toList()