Implemented a feature where the expression parser

can avoid running the code in the target if the
expression's result is known and the expression
has no side effects.

Right now this feature is quite conservative in
its guess about side effects, and it only computes
integer results, but the machinery to make it more
sophisticated is there.

llvm-svn: 121952

lldb/source/Expression/ClangExpressionParser.cpp

@@ -409,7 +409,8 @@ ClangExpressionParser::MakeDWARF ()
 Error
 ClangExpressionParser::MakeJIT (lldb::addr_t &func_addr, 
                                 lldb::addr_t &func_end, 
-                                ExecutionContext &exe_ctx)
+                                ExecutionContext &exe_ctx,
+                                lldb::ClangExpressionVariableSP *const_result)
 {
     lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
 
@@ -446,6 +447,7 @@ ClangExpressionParser::MakeJIT (lldb::addr_t &func_addr,
     {
         IRForTarget ir_for_target(decl_map, 
                                   m_expr.NeedsVariableResolution(),
+                                  const_result,
                                   function_name.c_str());
         
         if (!ir_for_target.runOnModule(*module))