diff --git a/framework/dwarf_operations.cpp b/framework/dwarf_operations.cpp
index dd33ce2..d7576f4 100644
--- a/framework/dwarf_operations.cpp
+++ b/framework/dwarf_operations.cpp
@@ -1078,6 +1078,25 @@ const dwarf_op_map* find_op_map(int op)
 	return NULL;
 }
 
+bool __dwarf_stack::is_expr_equal(__dwarf_stack* rhs)
+{
+    if(rhs->expr.Size() != expr.Size()) {
+        return false;
+    }
+
+    pst_dwarf_op* rop = (pst_dwarf_op*)rhs->expr.First();
+    pst_dwarf_op* lop = (pst_dwarf_op*)expr.First();
+    while(lop != NULL && rop != NULL) {
+        if(lop->operation != rop->operation || lop->arg1 != rop->arg1 || lop->arg2 != rop->arg2) {
+            return false;
+        }
+        lop = (pst_dwarf_op*)expr.Next(lop);
+        rop = (pst_dwarf_op*)rhs->expr.Next(rop);
+    }
+
+    return true;
+}
+
 bool __dwarf_stack::get_value(uint64_t& value)
 {
     if(!Size()) {
@@ -1114,6 +1133,9 @@ bool __dwarf_stack::calc_expression(Dwarf_Op *exprs, int expr_len, Dwarf_Attribu
             return false;
         }
 
+        pst_dwarf_op* op = new pst_dwarf_op(exprs[i].atom, exprs[i].number, exprs[i].number2);
+        expr.InsertLast(op);
+
         dwarf_value* v = get();
         // dereference register location there if it is not last in stack
         if(v && (v->type & DWARF_TYPE_REGISTER_LOC)) {
diff --git a/framework/dwarf_operations.h b/framework/dwarf_operations.h
index 6464f9a..bd0428b 100644
--- a/framework/dwarf_operations.h
+++ b/framework/dwarf_operations.h
@@ -3,6 +3,17 @@
 #include <elfutils/libdwfl.h>
 
 #include "common.h"
+#include "linkedlist.h"
+
+// DWARF operation (represents our own DW_OP_XXX)
+typedef struct __pst_dwarf_op : public SC_ListNode {
+    __pst_dwarf_op(uint8_t op, uint64_t a1, uint64_t a2) {
+        operation = op; arg1 = a1; arg2 = a2;
+    }
+    uint8_t                     operation;
+    uint64_t                    arg1;
+    uint64_t                    arg2;
+} pst_dwarf_op;
 
 typedef enum {
     DWARF_TYPE_INVALID      = 0,    // no type
@@ -62,11 +73,17 @@ typedef struct __dwarf_value : public SC_ListNode {
 } dwarf_value;
 
 typedef struct __dwarf_stack : public SC_ListHead {
-    __dwarf_stack(pst_context* c) : ctx(c)
-    {
+    __dwarf_stack(pst_context* c) : ctx(c) {
         attr = NULL;
     }
 
+    ~__dwarf_stack() {
+        for(pst_dwarf_op* op = (pst_dwarf_op*)expr.First(); op; op = (pst_dwarf_op*)expr.First()) {
+            expr.Remove(op);
+            delete op;
+        }
+    }
+
     void clear() {
         for(dwarf_value* v = (dwarf_value*)First(); v; v = (dwarf_value*)First()) {
             Remove(v);
@@ -74,6 +91,8 @@ typedef struct __dwarf_stack : public SC_ListHead {
         }
     }
 
+    bool is_expr_equal(__dwarf_stack* rhs);
+
     void push(void* v, uint32_t s, int t) {
         dwarf_value* value = new dwarf_value((char*)v, s, t);
         InsertFirst(value);
@@ -104,7 +123,8 @@ typedef struct __dwarf_stack : public SC_ListHead {
     bool calc_expression(Dwarf_Op *exprs, int expr_len, Dwarf_Attribute* attr);
     bool get_value(uint64_t& value);
 
-    Dwarf_Attribute*    attr; // attribute which expression currently processed
+    Dwarf_Attribute*    attr;   // attribute which expression currently processed
+    SC_ListHead         expr;   // DWARF expression
     pst_context*        ctx;
 } dwarf_stack;