[lldb] Initialize SwiftASTContext with embedded swift feature

In order for expression evaluation to work when debugging embedded swift
programs, the compiler instance needs to be initialized with the embedded
feature. The compiler writes "-enable-embedded-swift" into the CU's
debug info when compiling in embedded Swift.

Author: augusto2112

lldb/include/lldb/Core/Module.h

@@ -823,6 +823,8 @@ class Module : public std::enable_shared_from_this<Module>,
                                  std::optional<lldb::user_id_t> debugger_id);
 
   bool IsSwiftCxxInteropEnabled();
+
+  bool IsEmbeddedSwift();
 #endif
 
   // Return true if the file backing this module has changed since the module
@@ -1109,6 +1111,7 @@ class Module : public std::enable_shared_from_this<Module>,
   void ReportErrorIfModifyDetected(const llvm::formatv_object_base &payload);
 #ifdef LLDB_ENABLE_SWIFT
   LazyBool m_is_swift_cxx_interop_enabled = eLazyBoolCalculate;
+  LazyBool m_is_embedded_swift = eLazyBoolCalculate;
 #endif
 };
 

lldb/include/lldb/Target/Target.h

@@ -1289,6 +1289,8 @@ class Target : public std::enable_shared_from_this<Target>,
   bool IsSwiftREPL();
 
   bool IsSwiftCxxInteropEnabled();
+
+  bool IsEmbeddedSwift();
 private:
   void DisplayFallbackSwiftContextErrors(
       SwiftASTContextForExpressions *swift_ast_ctx);

lldb/source/Core/Module.cpp

@@ -1203,6 +1203,34 @@ bool Module::IsSwiftCxxInteropEnabled() {
   }
   return m_is_swift_cxx_interop_enabled == eLazyBoolYes;
 }
+
+bool Module::IsEmbeddedSwift() {
+  switch (m_is_embedded_swift) {
+  case eLazyBoolYes:
+    return true;
+  case eLazyBoolNo:
+    return false;
+  case eLazyBoolCalculate:
+    auto *sym_file = GetSymbolFile();
+    if (!sym_file)
+      return false;
+
+    m_is_embedded_swift = eLazyBoolNo;
+    auto options = sym_file->GetCompileOptions();
+    StringRef enable_embedded_swift("-enable-embedded-swift");
+    for (auto &[_, args] : options) {
+      for (const char *arg : args.GetArgumentArrayRef()) {
+        if (enable_embedded_swift == arg) {
+          m_is_embedded_swift = eLazyBoolYes;
+          return true;
+        }
+      }
+    }
+
+    return m_is_embedded_swift == eLazyBoolYes;
+  }
+}
+
 #endif
 
 void Module::ReportErrorIfModifyDetected(

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

@@ -1936,6 +1936,9 @@ SwiftASTContext::CreateInstance(lldb::LanguageType language, Module &module,
   swift_ast_sp->GetLanguageOptions().EnableCXXInterop =
       module.IsSwiftCxxInteropEnabled();
 
+  if (module.IsEmbeddedSwift())
+    swift_ast_sp->GetLanguageOptions().enableFeature(swift::Feature::Embedded);
+
   bool found_swift_modules = false;
   SymbolFile *sym_file = module.GetSymbolFile();
 
@@ -2357,6 +2360,10 @@ lldb::TypeSystemSP SwiftASTContext::CreateInstance(
 
   swift_ast_sp->GetLanguageOptions().EnableCXXInterop =
       target.IsSwiftCxxInteropEnabled();
+
+  if (target.IsEmbeddedSwift())
+    swift_ast_sp->GetLanguageOptions().enableFeature(swift::Feature::Embedded);
+
   bool handled_sdk_path = false;
   const size_t num_images = target.GetImages().GetSize();
 
@@ -2651,6 +2658,10 @@ lldb::TypeSystemSP SwiftASTContext::CreateInstance(
 
   swift_ast_sp->GetLanguageOptions().EnableCXXInterop =
       target.IsSwiftCxxInteropEnabled();
+
+  if (target.IsEmbeddedSwift())
+    swift_ast_sp->GetLanguageOptions().enableFeature(swift::Feature::Embedded);
+
   bool handled_sdk_path = false;
   const size_t num_images = target.GetImages().GetSize();
 

lldb/source/Target/Target.cpp

@@ -3188,6 +3188,14 @@ bool Target::IsSwiftCxxInteropEnabled() {
   return m_is_swift_cxx_interop_enabled == eLazyBoolYes;
 }
 
+bool Target::IsEmbeddedSwift() {
+  if (GetImages().IsEmpty())
+    return false;
+
+  // Embedded Swift cannot be mixed with non-embedded, so checking the first
+  // module should be enough.
+  return GetImages().GetModuleAtIndex(0)->IsEmbeddedSwift();
+}
 #endif // LLDB_ENABLE_SWIFT
 
 void Target::SettingsInitialize() { Process::SettingsInitialize(); }

lldb/test/API/lang/swift/embedded/expr/Makefile

@@ -0,0 +1,4 @@
+SWIFT_SOURCES := main.swift
+SWIFT_EMBEDDED_MODE := 1
+
+include Makefile.rules

lldb/test/API/lang/swift/embedded/expr/TestSwiftEmbeddedExpression.py

@@ -0,0 +1,18 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+import unittest2
+
+
+class TestSwiftEmbeddedExpression(TestBase):
+    @skipUnlessDarwin
+    @swiftTest
+    def test(self):
+        self.build()
+
+        target, process, _, _ = lldbutil.run_to_source_breakpoint(
+            self, "break here", lldb.SBFileSpec("main.swift")
+        )
+
+        self.expect("expr a.foo()", substrs=["(Int)", " = 16"])

lldb/test/API/lang/swift/embedded/expr/main.swift

@@ -0,0 +1,15 @@
+struct A {
+  var field = 4
+
+  func foo() -> Int {
+    return field * field
+  }
+}
+
+
+let a = A()
+// Dummy statement to set breakpoint print can't be used in embedded Swift for now.
+let dummy = A() // break here
+let string = StaticString("Hello") 
+print(string) 
+