Allow switching the Swift version in expressions

Author: adrian-prantl

lldb/source/Plugins/ExpressionParser/Swift/SwiftExpressionParser.cpp

@@ -1358,16 +1358,16 @@ SwiftExpressionParser::ParseAndImport(
   invocation.getFrontendOptions().ModuleName = expr_name_buf;
   invocation.getIRGenOptions().ModuleName = expr_name_buf;
 
+  auto &lang_opts = invocation.getLangOptions();
   bool enable_bare_slash_regex_literals =
       m_sc.target_sp->GetSwiftEnableBareSlashRegex();
-  if (enable_bare_slash_regex_literals) {
-    invocation.getLangOptions().enableFeature(
-        swift::Feature::BareSlashRegexLiterals);
-  }
-  if (uint32_t version = m_expr.Language().version) {
-    invocation.getLangOptions().EffectiveLanguageVersion =
+  if (enable_bare_slash_regex_literals)
+    lang_opts.enableFeature(swift::Feature::BareSlashRegexLiterals);
+  if (uint32_t version = m_expr.Language().version)
+    lang_opts.EffectiveLanguageVersion =
         llvm::VersionTuple(version / 100, version % 100);
-  }
+  if (lang_opts.EffectiveLanguageVersion >= swift::version::Version({6}))
+    lang_opts.StrictConcurrencyLevel = swift::StrictConcurrency::Complete;
 
   auto should_use_prestable_abi = [&]() {
     lldb::StackFrameSP this_frame_sp(m_stack_frame_wp.lock());
@@ -1380,8 +1380,7 @@ SwiftExpressionParser::ParseAndImport(
     return !runtime->IsABIStable();
   };
 
-  invocation.getLangOptions().UseDarwinPreStableABIBit =
-      should_use_prestable_abi();
+  lang_opts.UseDarwinPreStableABIBit = should_use_prestable_abi();
 
   LLDBNameLookup *external_lookup;
   if (m_options.GetPlaygroundTransformEnabled() || m_options.GetREPLEnabled()) {

lldb/test/API/lang/swift/expression/language_version/Makefile

@@ -0,0 +1,3 @@
+SWIFT_SOURCES := main.swift
+
+include Makefile.rules

lldb/test/API/lang/swift/expression/language_version/TestSwiftExpressionLanguageVersion.py

@@ -0,0 +1,34 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+import unittest2
+
+class TestSwiftExpressionLanguageVersion(TestBase):
+    NO_DEBUG_INFO_TESTCASE = True
+
+    @swiftTest
+    def test(self):
+        """Test changing the Swift language version"""
+        self.build()
+        target, process, thread, bkpt = lldbutil.run_to_name_breakpoint(
+            self, 'main')
+
+        expr = """\
+#if swift(>=6.0)
+6
+#else
+5
+#endif
+        """
+
+        def test_version(n):
+            if self.TraceOn():
+                print("Testing version %d"%n)
+            options = lldb.SBExpressionOptions()
+            options.SetLanguage(lldb.eLanguageNameSwift, n*100 + 0)
+            value = self.frame().EvaluateExpression(expr, options)
+            self.assertEquals(value.GetValue(), "%d" % n)
+
+        test_version(5)
+        test_version(6)

lldb/test/API/lang/swift/expression/language_version/main.swift

@@ -0,0 +1 @@
+print("break here")