Use topology sort for determining source file checking order

src/SourceFile.cpp

@@ -238,8 +238,15 @@ void SourceFile::runTypeChecker() { // NOLINT(misc-no-recursion)
   // We need two runs here due to generics.
   // The first run to determine all concrete substantiations of potentially generic elements
   runTypeCheckerPre(); // Visit dependency tree from bottom to top
+
+  // Compute best order of the source files to perform type checking
+  resourceManager.enqueueSourceFilesForTypeChecking();
   // The second run to ensure, also generic scopes are type-checked properly
-  runTypeCheckerPost(); // Visit dependency tree from top to bottom
+  while (!resourceManager.sourceFileVisitQueue.empty()) {
+    SourceFile *sourceFile = resourceManager.sourceFileVisitQueue.front();
+    sourceFile->runTypeCheckerPost();
+    resourceManager.sourceFileVisitQueue.pop();
+  }
 }
 
 void SourceFile::runTypeCheckerPre() { // NOLINT(misc-no-recursion)
@@ -265,38 +272,26 @@ void SourceFile::runTypeCheckerPre() { // NOLINT(misc-no-recursion)
 
 void SourceFile::runTypeCheckerPost() { // NOLINT(misc-no-recursion)
   // Skip if restored from cache, this stage has already been done or not all dependants finished type checking
-  if (restoredFromCache || !haveAllDependantsBeenTypeChecked())
+  if (restoredFromCache)
     return;
 
   Timer timer(&compilerOutput.times.typeCheckerPost);
   timer.start();
 
   // Start type-checking loop. The type-checker can request a re-execution. The max number of type-checker runs is limited
   TypeChecker typeChecker(resourceManager, this, TC_MODE_POST);
-  unsigned short typeCheckerRuns = 0;
-  do {
-    typeCheckerRuns++;
-    totalTypeCheckerRuns++;
-    reVisitRequested = false;
-
-    // Type-check the current file first. Multiple times, if requested
-    timer.resume();
-    typeChecker.visit(ast);
-    timer.pause();
-
-    // Then type-check all dependencies
-    for (SourceFile *sourceFile : dependencies | std::views::values)
-      sourceFile->runTypeCheckerPost();
-  } while (reVisitRequested);
+  typeChecker.visit(ast);
+  totalTypeCheckerRuns++;
 
+  // Check if there are soft errors and print them
   checkForSoftErrors();
 
   // Check if all dyn variables were type-inferred successfully
   globalScope->ensureSuccessfulTypeInference();
 
   previousStage = TYPE_CHECKER_POST;
   timer.stop();
-  printStatusMessage("Type Checker Post", IO_AST, IO_AST, compilerOutput.times.typeCheckerPost, typeCheckerRuns);
+  printStatusMessage("Type Checker Post", IO_AST, IO_AST, compilerOutput.times.typeCheckerPost, totalTypeCheckerRuns);
 
   // Save the JSON version in the compiler output
   if (cliOptions.dumpSettings.dumpSymbolTable || cliOptions.testMode)
@@ -545,8 +540,16 @@ void SourceFile::runFrontEnd() { // NOLINT(misc-no-recursion)
 void SourceFile::runMiddleEnd() {
   runTypeCheckerPre();
   CHECK_ABORT_FLAG_V()
-  runTypeCheckerPost();
-  CHECK_ABORT_FLAG_V()
+
+  // Compute best order of the source files to perform type checking
+  resourceManager.enqueueSourceFilesForTypeChecking();
+  // Visit the source files in this order
+  while (!resourceManager.sourceFileVisitQueue.empty()) {
+    SourceFile *sourceFile = resourceManager.sourceFileVisitQueue.front();
+    sourceFile->runTypeCheckerPost();
+    CHECK_ABORT_FLAG_V()
+    resourceManager.sourceFileVisitQueue.pop();
+  }
 }
 
 void SourceFile::runBackEnd() { // NOLINT(misc-no-recursion)
@@ -716,10 +719,6 @@ bool SourceFile::isRT(RuntimeModule runtimeModule) const {
   return exportedNameRegistry.at(topLevelName).targetEntry->scope == globalScope.get();
 }
 
-bool SourceFile::haveAllDependantsBeenTypeChecked() const {
-  return std::ranges::all_of(dependants, [](const SourceFile *dependant) { return dependant->totalTypeCheckerRuns >= 1; });
-}
-
 /**
  * Acquire all publicly visible symbols from the imported source file and put them in the name registry of the current one.
  * But only do that for the symbols that are actually defined in the imported source file. Do not allow transitive dependencies.
@@ -823,7 +822,7 @@ void SourceFile::printStatusMessage(const char *stage, const CompileStageIOType
     outputStr << compilerStageIoTypeName[in] << " --> " << compilerStageIoTypeName[out];
     outputStr << " (" << std::to_string(stageRuntime) << " ms";
     if (stageRuns > 0)
-      outputStr << "; " << std::to_string(stageRuns) << " run(s)";
+      outputStr << "; Run " << std::to_string(stageRuns);
     outputStr << ")\n";
     // Print
     std::cout << outputStr.str();

src/SourceFile.h

@@ -166,7 +166,6 @@ class SourceFile {
   bool alwaysKeepSymbolsOnNameCollision = false;
   bool ignoreWarnings = false;
   bool restoredFromCache = false;
-  bool reVisitRequested = false;
   CompileStageType previousStage = NONE;
   SourceFileAntlrCtx antlrCtx;
   CompilerOutput compilerOutput;
@@ -192,7 +191,6 @@ class SourceFile {
   uint8_t totalTypeCheckerRuns = 0;
 
   // Private methods
-  bool haveAllDependantsBeenTypeChecked() const;
   void mergeNameRegistries(const SourceFile &importedSourceFile, const std::string &importName);
   void dumpOutput(const std::string &content, const std::string &caption, const std::string &fileSuffix) const;
   void visualizerPreamble(std::stringstream &output) const;

src/global/GlobalResourceManager.cpp

@@ -61,7 +61,7 @@ GlobalResourceManager::~GlobalResourceManager() {
 SourceFile *GlobalResourceManager::createSourceFile(SourceFile *parent, const std::string &depName,
                                                     const std::filesystem::path &path, bool isStdFile) {
   // Check if the source file was already added (e.g. by another source file that imports it)
-  const std::string filePathStr = std::filesystem::weakly_canonical(std::filesystem::absolute(path)).string();
+  const std::string filePathStr = weakly_canonical(absolute(path)).string();
 
   // Create the new source file if it does not exist yet
   if (!sourceFiles.contains(filePathStr))
@@ -70,6 +70,36 @@ SourceFile *GlobalResourceManager::createSourceFile(SourceFile *parent, const st
   return sourceFiles.at(filePathStr).get();
 }
 
+void GlobalResourceManager::enqueueSourceFilesForTypeChecking() {
+  assert(sourceFileVisitQueue.empty());
+  std::stack<SourceFile *> stack;
+  std::unordered_set<std::string> visited;
+
+  // Call the recursive helper function to store topological sort starting from all files
+  for (auto &[name, sourceFile] : sourceFiles)
+    if (!visited.contains(sourceFile->name))
+      topologicalSortHelper(sourceFile.get(), visited, stack);
+
+  while (!stack.empty()) {
+    sourceFileVisitQueue.push(stack.top());
+    stack.pop();
+  }
+}
+
+void GlobalResourceManager::topologicalSortHelper(SourceFile *file, std::unordered_set<std::string> &visited,
+                                                  std::stack<SourceFile *> &stack) {
+  // Mark the current node as visited
+  visited.insert(file->name);
+
+  // Recur for all the dependencies of this source file
+  for (auto &[name, sourceFile] : file->dependencies)
+    if (!visited.contains(name))
+      topologicalSortHelper(sourceFile, visited, stack);
+
+  // Push the current source file to the stack
+  stack.push(file);
+}
+
 uint64_t GlobalResourceManager::getNextCustomTypeId() { return nextCustomTypeId++; }
 
 size_t GlobalResourceManager::getTotalLineCount() const {

src/global/GlobalResourceManager.h

@@ -7,7 +7,6 @@
 #include <global/RuntimeModuleManager.h>
 #include <linker/ExternalLinkerInterface.h>
 #include <util/BlockAllocator.h>
-#include <util/CodeLoc.h>
 #include <util/Timer.h>
 
 #include <llvm/IR/LLVMContext.h>
@@ -36,6 +35,8 @@ class GlobalResourceManager {
 
   // Public methods
   SourceFile *createSourceFile(SourceFile *parent, const std::string &depName, const std::filesystem::path &path, bool isStdFile);
+  void enqueueSourceFilesForTypeChecking();
+  static void topologicalSortHelper(SourceFile* file, std::unordered_set<std::string>& visited, std::stack<SourceFile*>& stack);
   uint64_t getNextCustomTypeId();
   size_t getTotalLineCount() const;
 
@@ -55,6 +56,7 @@ class GlobalResourceManager {
   RuntimeModuleManager runtimeModuleManager;
   Timer totalTimer;
   ErrorManager errorManager;
+  std::queue<SourceFile *> sourceFileVisitQueue; // Used for queueing type checking in the correct order
   bool abortCompilation = false;
 
 private:

src/typechecker/TypeChecker.cpp

@@ -2667,8 +2667,9 @@ std::vector<const Function *> &TypeChecker::getOpFctPointers(ASTNode *node) cons
  * @param fct Function to check
  */
 void TypeChecker::requestRevisitIfRequired(const Function *fct) const {
+  // Push source file to the back of the processing queue
   if (fct && !fct->alreadyTypeChecked && !fct->entry->scope->isImportedBy(rootScope))
-    fct->entry->scope->sourceFile->reVisitRequested = true;
+    resourceManager.sourceFileVisitQueue.push(fct->entry->scope->sourceFile);
 }
 
 /**