Get a dummy target to allow for calculator mode while processing backticks.

This also helps break the infinite loop caused when target is null.

So that we can have:

$ /Volumes/data/lldb/svn/trunk/build/Debug/lldb
(lldb) itob `0x123 - 0x321` 32 v
 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
 [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0]
(lldb) 

llvm-svn: 143260

1 files changed, 4 insertions, 0 deletions

diff --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
index dfb4d5963d7..fb5fc4c9871 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -1070,6 +1070,10 @@ CommandInterpreter::PreprocessCommand (std::string &command)
                 std::string expr_str (command, expr_content_start, end_backtick - expr_content_start);
                 
                 Target *target = m_exe_ctx.GetTargetPtr();
+                // Get a dummy target to allow for calculator mode while processing backticks.
+                // This also helps break the infinite loop caused when target is null.
+                if (!target)
+                    target = Host::GetDummyTarget(GetDebugger()).get();
                 if (target)
                 {
                     const bool unwind_on_error = true;