Set the default language to use when evaluating to that of the frame's CU.

* Use the frame's context (instead of just the target's) when evaluating,
  so that the language of the frame's CU can be used to select the
  compiler and/or compiler options to use when parsing the expression.
  This allows for modules built with mixed languages to be parsed in
  the context of their frame. 
* Add all C and C++ language variants when determining the language options
  to set.
* Enable C++ language options when language is C or ObjC as a workaround since
  the expression parser uses features of C++ to capture values.
* Enable ObjC language options when language is C++ as a workaround for ObjC
  requirements.
* Disable C++11 language options when language is C++03.
* Add test TestMixedLanguages.py to check that the language being used
  for evaluation is that of the frame.
* Fix test TestExprOptions.py to check for C++11 instead of C++ since C++ has
  to be enabled for C, and remove redundant expr --language test for ObjC.
* Fix TestPersistentPtrUpdate.py to not require C++11 in C.

Reviewed by: clayborg, spyffe, jingham
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D11102

llvm-svn: 246829

1 files changed, 8 insertions, 5 deletions

diff --git a/lldb/source/Commands/CommandObjectExpression.cpp b/lldb/source/Commands/CommandObjectExpression.cpp
index 4aa486c..7e787bc 100644
--- a/lldb/source/Commands/CommandObjectExpression.cpp
+++ b/lldb/source/Commands/CommandObjectExpression.cpp
@@ -289,8 +289,8 @@ CommandObjectExpression::EvaluateExpression
     if (target)
     {
         lldb::ValueObjectSP result_valobj_sp;
-
         bool keep_in_memory = true;
+        StackFrame *frame = exe_ctx.GetFramePtr();
 
         EvaluateExpressionOptions options;
         options.SetCoerceToId(m_varobj_options.use_objc);
@@ -301,11 +301,15 @@ CommandObjectExpression::EvaluateExpression
         options.SetTryAllThreads(m_command_options.try_all_threads);
         options.SetDebug(m_command_options.debug);
         
-        // If the language was not specified, set it from target's properties
+        // If the language was not specified in the expression command,
+        // set it to the language in the target's properties if
+        // specified, else default to the langage for the frame.
         if (m_command_options.language != eLanguageTypeUnknown)
             options.SetLanguage(m_command_options.language);
-        else
+        else if (target->GetLanguage() != eLanguageTypeUnknown)
             options.SetLanguage(target->GetLanguage());
+        else if (frame)
+            options.SetLanguage(frame->GetLanguage());
 
         // If there is any chance we are going to stop and want to see
         // what went wrong with our expression, we should generate debug info
@@ -318,8 +322,7 @@ CommandObjectExpression::EvaluateExpression
         else
             options.SetTimeoutUsec(0);
 
-        target->EvaluateExpression(expr, exe_ctx.GetFramePtr(),
-                                   result_valobj_sp, options);
+        target->EvaluateExpression(expr, frame, result_valobj_sp, options);
 
         if (result_valobj_sp)
         {