Merge pull request swiftlang#75146 from artemcm/DepScanNoGlobalLLVMOpts

[Dependency Scanning] Avoid configuration (and reset) of LLVM Options by the scanner

Author: artemcm

lib/DependencyScan/DependencyScanningTool.cpp

@@ -35,11 +35,6 @@ llvm::ErrorOr<swiftscan_string_ref_t> getTargetInfo(ArrayRef<const char *> Comma
                                                     const char *main_executable_path) {
   llvm::sys::SmartScopedLock<true> Lock(TargetInfoMutex);
 
-  // We must reset option occurrences because we are handling an unrelated
-  // command-line to those possibly parsed before using the same tool.
-  // We must do so because LLVM options parsing is done using a managed
-  // static `GlobalParser`.
-  llvm::cl::ResetAllOptionOccurrences();
   // Parse arguments.
   std::string CommandString;
   for (const auto *c : Command) {
@@ -411,8 +406,7 @@ DependencyScanningTool::initCompilerInstanceForScan(
     StringRef WorkingDir,
     std::shared_ptr<DependencyScanDiagnosticCollector> scannerDiagnosticsCollector) {
   // The remainder of this method operates on shared state in the
-  // scanning service and global LLVM state with:
-  // llvm::cl::ResetAllOptionOccurrences
+  // scanning service
   llvm::sys::SmartScopedLock<true> Lock(DependencyScanningToolStateLock);
   // FIXME: Instead, target-info and supported-features queries must use
   // `DependencyScanningToolStateLock`, but this currently requires further
@@ -438,11 +432,6 @@ DependencyScanningTool::initCompilerInstanceForScan(
   if (WorkingDirectory.empty())
     llvm::sys::fs::current_path(WorkingDirectory);
 
-  // We must reset option occurrences because we are handling an unrelated
-  // command-line to those possibly parsed before using the same tool.
-  // We must do so because LLVM options parsing is done using a managed
-  // static `GlobalParser`.
-  llvm::cl::ResetAllOptionOccurrences();
   // Parse/tokenize arguments.
   std::string CommandString;
   for (const auto *c : CommandArgs) {

lib/DependencyScan/ScanDependencies.cpp

@@ -1141,11 +1141,6 @@ forEachBatchEntry(CompilerInstance &invocationInstance,
       // those of the current scanner invocation.
       updateCachedInstanceOpts(*pInstance, invocationInstance, entry.arguments);
     } else {
-      // We must reset option occurrences because we are handling an unrelated command-line
-      // to those parsed before. We must do so because LLVM options parsing is done
-      // using a managed static `GlobalParser`.
-      llvm::cl::ResetAllOptionOccurrences();
-
       // Create a new instance by the arguments and save it in the map.
       auto newService = std::make_unique<SwiftDependencyScanningService>();
       auto newInstance = std::make_unique<CompilerInstance>();

lib/Frontend/Frontend.cpp

@@ -691,15 +691,21 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
 }
 
 void CompilerInstance::setUpLLVMArguments() {
-  // Honor -Xllvm.
-  if (!Invocation.getFrontendOptions().LLVMArgs.empty()) {
-    llvm::SmallVector<const char *, 4> Args;
-    Args.push_back("swift (LLVM option parsing)");
-    for (unsigned i = 0, e = Invocation.getFrontendOptions().LLVMArgs.size();
-         i != e; ++i)
-      Args.push_back(Invocation.getFrontendOptions().LLVMArgs[i].c_str());
-    Args.push_back(nullptr);
-    llvm::cl::ParseCommandLineOptions(Args.size()-1, Args.data());
+  // Dependency scanning has no need for LLVM options, and
+  // must not use `llvm::cl::` utilities operating on global state
+  // since dependency scanning is multi-threaded.
+  if (Invocation.getFrontendOptions().RequestedAction !=
+      FrontendOptions::ActionType::ScanDependencies) {
+    // Honor -Xllvm.
+    if (!Invocation.getFrontendOptions().LLVMArgs.empty()) {
+      llvm::SmallVector<const char *, 4> Args;
+      Args.push_back("swift (LLVM option parsing)");
+      for (unsigned i = 0, e = Invocation.getFrontendOptions().LLVMArgs.size();
+           i != e; ++i)
+        Args.push_back(Invocation.getFrontendOptions().LLVMArgs[i].c_str());
+      Args.push_back(nullptr);
+      llvm::cl::ParseCommandLineOptions(Args.size()-1, Args.data());
+    }
   }
 }