Performance optimizations to ClangUserExpression,

mostly related to management of the stack frame
for the interpreter.

  - First, if the expression can be interpreted,
    allocate the stack frame in the target process
    (to make sure pointers are valid) but only
    read/write to the copy in the host's memory.

  - Second, keep the memory allocations for the
    stack frame and the materialized struct as
    member variables of ClangUserExpression.  This
    avoids memory allocations and deallocations
    each time the expression runs.

<rdar://problem/13043685>

llvm-svn: 180664

1 files changed, 2 insertions, 2 deletions

diff --git a/lldb/source/Expression/Materializer.cpp b/lldb/source/Expression/Materializer.cpp
index af941d8..20ccc1f 100644
--- a/lldb/source/Expression/Materializer.cpp
+++ b/lldb/source/Expression/Materializer.cpp
@@ -822,7 +822,7 @@ public:
         
         lldb::ProcessSP process_sp = map.GetBestExecutionContextScope()->CalculateProcess();
         
-        bool can_persist = (process_sp && process_sp->CanJIT());
+        bool can_persist = (m_is_program_reference && process_sp && process_sp->CanJIT() && !(address >= frame_bottom && address < frame_top));
 
         if (can_persist && m_keep_in_memory)
         {
@@ -1316,7 +1316,7 @@ Materializer::Materialize (lldb::StackFrameSP &frame_sp, IRMemoryMap &map, lldb:
 }
 
 void
-Materializer::Dematerializer::Dematerialize (Error &error, lldb::ClangExpressionVariableSP &result_sp, lldb::addr_t frame_top, lldb::addr_t frame_bottom)
+Materializer::Dematerializer::Dematerialize (Error &error, lldb::ClangExpressionVariableSP &result_sp, lldb::addr_t frame_bottom, lldb::addr_t frame_top)
 {
     lldb::StackFrameSP frame_sp = m_frame_wp.lock();