[lldb] Mark single-argument SourceLanguage constructors explicit (llvm#166527)

This avoids unintentional comparisons between `SourceLanguage` and
`LanguageType`.

Also marks `operator bool` explicit so we don't implicitly convert to
bool.

Author: Michael137

lldb/include/lldb/lldb-private-types.h

@@ -102,13 +102,18 @@ struct RegisterSet {
 /// A type-erased pair of llvm::dwarf::SourceLanguageName and version.
 struct SourceLanguage {
   SourceLanguage() = default;
-  SourceLanguage(lldb::LanguageType language_type);
+  explicit SourceLanguage(lldb::LanguageType language_type);
+
   SourceLanguage(uint16_t name, uint32_t version)
       : name(name), version(version) {}
-  SourceLanguage(std::optional<std::pair<uint16_t, uint32_t>> name_vers)
+
+  explicit SourceLanguage(
+      std::optional<std::pair<uint16_t, uint32_t>> name_vers)
       : name(name_vers ? name_vers->first : 0),
         version(name_vers ? name_vers->second : 0) {}
-  operator bool() const { return name > 0; }
+
+  explicit operator bool() const { return name > 0; }
+
   lldb::LanguageType AsLanguageType() const;
   llvm::StringRef GetDescription() const;
   bool IsC() const;

lldb/source/Breakpoint/BreakpointLocation.cpp

@@ -251,7 +251,7 @@ bool BreakpointLocation::ConditionSaysStop(ExecutionContext &exe_ctx,
     }
 
     m_user_expression_sp.reset(GetTarget().GetUserExpressionForLanguage(
-        condition.GetText(), llvm::StringRef(), language,
+        condition.GetText(), llvm::StringRef(), SourceLanguage{language},
         Expression::eResultTypeAny, EvaluateExpressionOptions(), nullptr,
         error));
     if (error.Fail()) {

lldb/source/Commands/CommandObjectDWIMPrint.cpp

@@ -95,9 +95,9 @@ void CommandObjectDWIMPrint::DoExecute(StringRef command,
   StackFrame *frame = m_exe_ctx.GetFramePtr();
 
   // Either the language was explicitly specified, or we check the frame.
-  lldb::LanguageType language = m_expr_options.language;
-  if (language == lldb::eLanguageTypeUnknown && frame)
-    language = frame->GuessLanguage().AsLanguageType();
+  SourceLanguage language{m_expr_options.language};
+  if (!language && frame)
+    language = frame->GuessLanguage();
 
   // Add a hint if object description was requested, but no description
   // function was implemented.
@@ -119,8 +119,8 @@ void CommandObjectDWIMPrint::DoExecute(StringRef command,
         "^<\\S+: 0x[[:xdigit:]]{5,}>\\s*$");
 
     if (GetDebugger().GetShowDontUsePoHint() && target_ptr &&
-        (language == lldb::eLanguageTypeSwift ||
-         language == lldb::eLanguageTypeObjC) &&
+        (language.AsLanguageType() == lldb::eLanguageTypeSwift ||
+         language.IsObjC()) &&
         std::regex_match(output.data(), swift_class_regex)) {
 
       result.AppendNote(
@@ -193,7 +193,8 @@ void CommandObjectDWIMPrint::DoExecute(StringRef command,
 
   // Second, try `expr` as a persistent variable.
   if (expr.starts_with("$"))
-    if (auto *state = target.GetPersistentExpressionStateForLanguage(language))
+    if (auto *state = target.GetPersistentExpressionStateForLanguage(
+            language.AsLanguageType()))
       if (auto var_sp = state->GetVariable(expr))
         if (auto valobj_sp = var_sp->GetValueObject()) {
           dump_val_object(*valobj_sp);

lldb/source/Expression/UserExpression.cpp

@@ -246,7 +246,7 @@ UserExpression::Evaluate(ExecutionContext &exe_ctx,
   // language in the target's properties if specified, else default to the
   // langage for the frame.
   if (!language) {
-    if (target->GetLanguage() != lldb::eLanguageTypeUnknown)
+    if (target->GetLanguage())
       language = target->GetLanguage();
     else if (StackFrame *frame = exe_ctx.GetFramePtr())
       language = frame->GetLanguage();

lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp

@@ -1502,7 +1502,7 @@ lldb_private::Status ClangExpressionParser::DoPrepareForExecution(
     LLDB_LOGF(log, "%s - Current expression language is %s\n", __FUNCTION__,
               lang.GetDescription().data());
     lldb::ProcessSP process_sp = exe_ctx.GetProcessSP();
-    if (process_sp && lang != lldb::eLanguageTypeUnknown) {
+    if (process_sp && lang) {
       auto runtime = process_sp->GetLanguageRuntime(lang.AsLanguageType());
       if (runtime)
         runtime->GetIRPasses(custom_passes);

lldb/source/Target/StackFrame.cpp

@@ -1344,18 +1344,18 @@ const char *StackFrame::GetDisplayFunctionName() {
 SourceLanguage StackFrame::GetLanguage() {
   CompileUnit *cu = GetSymbolContext(eSymbolContextCompUnit).comp_unit;
   if (cu)
-    return cu->GetLanguage();
+    return SourceLanguage{cu->GetLanguage()};
   return {};
 }
 
 SourceLanguage StackFrame::GuessLanguage() {
   SourceLanguage lang_type = GetLanguage();
 
-  if (lang_type == eLanguageTypeUnknown) {
+  if (!lang_type) {
     SymbolContext sc =
         GetSymbolContext(eSymbolContextFunction | eSymbolContextSymbol);
     if (sc.function)
-      lang_type = LanguageType(sc.function->GetMangled().GuessLanguage());
+      lang_type = SourceLanguage(sc.function->GetMangled().GuessLanguage());
     else if (sc.symbol)
       lang_type = SourceLanguage(sc.symbol->GetMangled().GuessLanguage());
   }

lldb/source/Target/Target.cpp

@@ -4945,7 +4945,7 @@ void TargetProperties::SetStandardErrorPath(llvm::StringRef path) {
 
 SourceLanguage TargetProperties::GetLanguage() const {
   const uint32_t idx = ePropertyLanguage;
-  return {GetPropertyAtIndexAs<LanguageType>(idx, {})};
+  return SourceLanguage{GetPropertyAtIndexAs<LanguageType>(idx, {})};
 }
 
 llvm::StringRef TargetProperties::GetExpressionPrefixContents() {