Precise compiler invocations: Set C++ interoperability per SymbolContext

lldb/source/Core/Module.cpp

@@ -1188,7 +1188,9 @@ bool Module::IsSwiftCxxInteropEnabled() {
     auto *sym_file = GetSymbolFile();
     if (sym_file) {
       auto options = sym_file->GetCompileOptions();
-      for (auto &[_, args] : options) {
+      for (auto &[cu, args] : options) {
+        if (cu->GetLanguage() != eLanguageTypeSwift)
+          continue;
         for (const char *arg : args.GetArgumentArrayRef()) {
           if (strcmp(arg, "-enable-experimental-cxx-interop") == 0) {
             m_is_swift_cxx_interop_enabled = eLazyBoolYes;

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

@@ -2172,6 +2172,41 @@ SwiftASTContext::CreateInstance(lldb::LanguageType language, Module &module,
   return swift_ast_sp;
 }
 
+/// Determine whether this CU was compiled with C++ interop enabled.
+static bool ShouldEnableCXXInterop(CompileUnit *cu) {
+  AutoBool interop_enabled =
+    ModuleList::GetGlobalModuleListProperties().GetSwiftEnableCxxInterop();
+  switch (interop_enabled) {
+  case AutoBool::True:
+    return true;
+  case AutoBool::False:
+    return false;
+  case AutoBool::Auto: {
+    if (!cu)
+      return false;
+    lldb::ModuleSP module = cu->CalculateSymbolContextModule();
+    if (!module)
+      return false;
+    // Look for the "-enable-experimental-cxx-interop" compile flag in the
+    // args of the compile units this module is composed of.
+    auto *sym_file = module->GetSymbolFile();
+    if (!sym_file)
+      return false;
+    auto options = sym_file->GetCompileOptions();
+    for (auto &[unit, args] : options) {
+      if (unit.get() == cu) {
+        if (cu->GetLanguage() == eLanguageTypeSwift)
+          for (const char *arg : args.GetArgumentArrayRef())
+            if (strcmp(arg, "-enable-experimental-cxx-interop") == 0)
+              return true;
+        return false;
+      }
+    }
+  }
+  }
+  return false;
+}
+
 static bool IsUnitTestExecutable(lldb_private::Module &module) {
   static ConstString s_xctest("xctest");
   static ConstString s_XCTRunner("XCTRunner");
@@ -2728,7 +2763,7 @@ lldb::TypeSystemSP SwiftASTContext::CreateInstance(
   swift_ast_sp->m_is_scratch_context = true;
 
   swift_ast_sp->GetLanguageOptions().EnableCXXInterop =
-      target.IsSwiftCxxInteropEnabled();
+      ShouldEnableCXXInterop(cu);
 
   if (target.IsEmbeddedSwift())
     swift_ast_sp->GetLanguageOptions().enableFeature(swift::Feature::Embedded);

lldb/test/API/lang/swift/cxx_interop/forward/langopt/Dylib.swift

@@ -0,0 +1,3 @@
+public func f() {
+  print("break here")
+}

lldb/test/API/lang/swift/cxx_interop/forward/langopt/Makefile

@@ -0,0 +1,21 @@
+SWIFT_SOURCES := main.swift
+SWIFT_CXX_INTEROP := 1
+SWIFTFLAGS_EXTRAS = -I.
+LD_EXTRAS = -L$(BUILDDIR) -lDylib
+
+all: libDylib.dylib a.out
+
+include Makefile.rules
+
+libDylib.dylib: Dylib.swift
+	$(MAKE) MAKE_DSYM=$(MAKE_DSYM) CC=$(CC) SWIFTC=$(SWIFTC) \
+		ARCH=$(ARCH) DSYMUTIL=$(DSYMUTIL) \
+		VPATH=$(SRCDIR) -I $(SRCDIR) \
+		-f $(THIS_FILE_DIR)/Makefile.rules \
+		DYLIB_SWIFT_SOURCES=Dylib.swift \
+		DYLIB_NAME=Dylib \
+		DYLIB_ONLY=YES \
+		SWIFT_SOURCES= \
+		SWIFT_CXX_INTEROP=0 \
+		SWIFT_BRIDGING_HEADER= \
+		all

lldb/test/API/lang/swift/cxx_interop/forward/langopt/TestSwiftForwardInteropCxxLangOpt.py

@@ -0,0 +1,32 @@
+
+"""
+Test that a C++ class is visible in Swift.
+"""
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+
+
+class TestSwiftForwardInteropCxxLangOpt(TestBase):
+
+    @swiftTest
+    @expectedFailureAll(setting=('symbols.swift-precise-compiler-invocation', 'false'))
+    def test_class(self):
+        """
+        Test that C++ interoperability is enabled on a per-CU basis.
+        """
+        self.build()
+        log = self.getBuildArtifact("types.log")
+        self.runCmd('log enable lldb types -f "%s"' % log)
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, 'break here', lldb.SBFileSpec('main.swift'),
+            extra_images=['Dylib'])
+        dylib_bkpt = target.BreakpointCreateBySourceRegex(
+            'break here', lldb.SBFileSpec('Dylib.swift'))
+        self.assertGreater(dylib_bkpt.GetNumLocations(), 0, VALID_BREAKPOINT)
+        self.expect('expr 0')
+        lldbutil.continue_to_breakpoint(process, dylib_bkpt)
+        self.expect('expr 1')
+        self.filecheck('platform shell cat ""%s"' % log, __file__)
+#       CHECK: SwiftASTContextForExpressions(module: "a", cu: "main.swift")::LogConfiguration(){{.*}}Swift/C++ interop : on
+#       CHECK:  SwiftASTContextForExpressions(module: "Dylib", cu: "Dylib.swift")::LogConfiguration(){{.*}}Swift/C++ interop : off
+

lldb/test/API/lang/swift/cxx_interop/forward/langopt/bridging.h

@@ -0,0 +1,10 @@
+
+struct CxxClass {
+  long long a1 = 10;
+  long long a2 = 20;
+  long long a3 = 30;
+};
+
+struct InheritedCxxClass: CxxClass {
+  long long a4 = 40;
+};

lldb/test/API/lang/swift/cxx_interop/forward/langopt/main.swift

@@ -0,0 +1,4 @@
+import Dylib
+
+print("break here")
+f()