Add the ability for an SBValue to create a persisted version of itself.

Such a persisted version is equivalent to evaluating the value via the expression evaluator, and holding on to the $n result of the expression, except this API can be used on SBValues that do not obviously come from an expression (e.g. are the result of a memory lookup)

Expose this via SBValue::Persist() in our public API layer, and ValueObject::Persist() in the lldb_private layer

Includes testcase

Fixes rdar://19136664

llvm-svn: 223711

1 files changed, 26 insertions, 0 deletions

diff --git a/lldb/source/Core/ValueObject.cpp b/lldb/source/Core/ValueObject.cpp
index 1c3d1487d0c..f6d1352c407 100644
--- a/lldb/source/Core/ValueObject.cpp
+++ b/lldb/source/Core/ValueObject.cpp
@@ -37,6 +37,9 @@
 #include "lldb/DataFormatters/StringPrinter.h"
 #include "lldb/DataFormatters/ValueObjectPrinter.h"
 
+#include "lldb/Expression/ClangExpressionVariable.h"
+#include "lldb/Expression/ClangPersistentVariables.h"
+
 #include "lldb/Host/Endian.h"
 
 #include "lldb/Interpreter/CommandInterpreter.h"
@@ -4180,3 +4183,26 @@ ValueObject::CanProvideValue ()
 {
     return (false == GetClangType().IsAggregateType());
 }
+
+ValueObjectSP
+ValueObject::Persist ()
+{
+    if (!UpdateValueIfNeeded())
+        return nullptr;
+    
+    TargetSP target_sp(GetTargetSP());
+    if (!target_sp)
+        return nullptr;
+    
+    ConstString name(target_sp->GetPersistentVariables().GetNextPersistentVariableName());
+    
+    ClangExpressionVariableSP clang_var_sp(new ClangExpressionVariable(target_sp.get(), GetValue(), name));
+    if (clang_var_sp)
+    {
+        clang_var_sp->m_live_sp = clang_var_sp->m_frozen_sp;
+        clang_var_sp->m_flags |= ClangExpressionVariable::EVIsProgramReference;
+        target_sp->GetPersistentVariables().AddVariable(clang_var_sp);
+    }
+    
+    return clang_var_sp->GetValueObject();
+}