Merge pull request #12011 from adrian-prantl/166574409

[LLDB] Disable implicit modules when importting current CU dependencies

Author: adrian-prantl

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -1859,9 +1859,11 @@ void SwiftASTContext::AddExtraClangArgs(
   swift::ClangImporterOptions &importer_options = GetClangImporterOptions();
   auto defer = llvm::make_scope_exit([&]() {
     // Detect explicitly-built modules.
-    m_has_explicit_modules =
-        llvm::any_of(importer_options.ExtraArgs, [](const std::string &arg) {
-          return StringRef(arg).starts_with("-fmodule-file=");
+    m_has_explicit_modules |=
+        llvm::any_of(importer_options.ExtraArgs, [](const std::string &s) {
+          StringRef arg(s);
+          return arg.starts_with("-fno-implicit-module") ||
+                 arg.starts_with("-fmodule-file=");
         });
     ConfigureModuleValidation(importer_options.ExtraArgs);
   });
@@ -3891,8 +3893,11 @@ ThreadSafeASTContext SwiftASTContext::GetASTContext() {
             *static_cast<swift::ModuleInterfaceCheckerImpl *>(
                 m_ast_context_up->getModuleInterfaceChecker()),
             m_dependency_tracker.get(), loading_mode));
-    if (module_interface_loader_up)
+    if (module_interface_loader_up) {
+      m_module_interface_loader = static_cast<swift::ModuleInterfaceLoader *>(
+          module_interface_loader_up.get());
       m_ast_context_up->addModuleLoader(std::move(module_interface_loader_up));
+    }
   }
 
   // 4. Create and install the serialized module loader.
@@ -9413,6 +9418,42 @@ bool SwiftASTContext::GetCompileUnitImportsImpl(
     llvm::SmallVectorImpl<swift::AttributedImport<swift::ImportedModule>>
         *modules,
     Status &error) {
+  // If EBM is enabled, disable implicit modules during contextual imports.
+  // fixme nullptr!
+  bool turn_off_implicit = m_has_explicit_modules;
+  auto reset = llvm::make_scope_exit([&] {
+    if (turn_off_implicit) {
+      LOG_PRINTF(GetLog(LLDBLog::Types), "Turning on implicit modules");
+      if (m_module_interface_loader) {
+        auto &opts = m_module_interface_loader->getOptions();
+        opts.disableImplicitSwiftModule = false;
+        opts.disableBuildingInterface = false;
+      }
+      if (m_clangimporter) {
+        auto &clang_instance = const_cast<clang::CompilerInstance &>(
+            m_clangimporter->getClangInstance());
+        clang_instance.getLangOpts().ImplicitModules = true;
+      }
+    }
+  });
+  if (turn_off_implicit) {
+    LOG_PRINTF(GetLog(LLDBLog::Types), "Turning off implicit modules");
+    // Swift.
+    if (m_module_interface_loader) {
+      auto &opts = m_module_interface_loader->getOptions();
+      opts.disableImplicitSwiftModule = true;
+      opts.disableBuildingInterface = true;
+    }
+    // Clang.
+    if (m_clangimporter) {
+      auto &clang_instance = const_cast<clang::CompilerInstance &>(
+          m_clangimporter->getClangInstance());
+      // AddExtraArgs is supposed to always turn implicit modules on.
+      assert(clang_instance.getLangOpts().ImplicitModules &&
+             "ClangImporter implicit module support is off");
+      clang_instance.getLangOpts().ImplicitModules = false;
+    }
+  }
 
   CompileUnit *compile_unit = sc.comp_unit;
   if (compile_unit && compile_unit->GetModule())

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.h

@@ -52,6 +52,7 @@ class SourceFile;
 class CASOptions;
 struct PrintOptions;
 class MemoryBufferSerializedModuleLoader;
+class ModuleInterfaceLoader;
 namespace Demangle {
 class Demangler;
 class Node;
@@ -976,6 +977,7 @@ class SwiftASTContext : public TypeSystemSwift {
   swift::MemoryBufferSerializedModuleLoader *m_memory_buffer_module_loader =
       nullptr;
   swift::ModuleLoader *m_explicit_swift_module_loader = nullptr;
+  swift::ModuleInterfaceLoader *m_module_interface_loader = nullptr;
   swift::ClangImporter *m_clangimporter = nullptr;
   /// Wraps the clang::ASTContext owned by ClangImporter.
   std::shared_ptr<TypeSystemClang> m_clangimporter_typesystem;

lldb/test/API/lang/swift/explicit_modules/implicit_fallback/TestSwiftExplicitModulesImplicitFallback.py

@@ -27,3 +27,29 @@ def test_missing_explicit_modules(self):
 
         self.filecheck(f"platform shell cat {log}", __file__)
         # CHECK: Nonexistent explicit module file
+        # CHECK: Explicit modules : false
+
+    @swiftTest
+    def test_sanity(self):
+        """Check the normal behavior."""
+        self.build()
+
+        # This test verifies the case where explicit modules are missing.
+        # Remove explicit modules from their place in the module cache.
+        mod_cache = self.getBuildArtifact("private-module-cache")
+
+        lldbutil.run_to_source_breakpoint(
+            self, "Set breakpoint here", lldb.SBFileSpec("main.swift")
+        )
+
+        log = self.getBuildArtifact("types.log")
+        self.runCmd(f"log enable lldb types -f '{log}'")
+
+        self.expect("expression c")
+        self.expect("expression -- import Foundation")
+
+        self.filecheck(f"platform shell cat {log}", __file__,
+                       '--check-prefix=CHECK-SANITY')
+        # CHECK-SANITY: Explicit modules : true
+        # CHECK-SANITY: Turning off implicit modules
+        # CHECK-SANITY: Turning on implicit modules