Add basic analysis for node NE_EXPR.

4 files changed, 37 insertions, 3 deletions

diff --git a/src/analysis/analysis.cpp b/src/analysis/analysis.cpp
index 9a890dd..459e517 100644
--- a/src/analysis/analysis.cpp
+++ b/src/analysis/analysis.cpp
@@ -34,6 +34,7 @@
 
 #include "nodes/expr/addr_expr.h"
 #include "nodes/expr/modify_expr.h"
+#include "nodes/expr/ne_expr.h"
 #include "nodes/expr/nop_expr.h"
 #include "nodes/expr/pointerplus_expr.h"
 #include "nodes/expr/return_expr.h"
@@ -177,6 +178,9 @@ void analyseNode(Node *node, const WalkItem &wi, WalkItem &wo)
         case MODIFY_EXPR:
             analyseModifyExpr(static_cast<ModifyExprNode*>(node), wi2, wo);
             break;
+        case NE_EXPR:
+            analyseNeExpr(static_cast<NeExprNode*>(node), wi2, wo);
+            break;
         case RETURN_EXPR:
             analyseReturnExpr(static_cast<ReturnExprNode*>(node), wi2, wo);
             break;
diff --git a/src/analysis/expression.cpp b/src/analysis/expression.cpp
index 3d9f0f6..666d448 100644
--- a/src/analysis/expression.cpp
+++ b/src/analysis/expression.cpp
@@ -27,6 +27,7 @@
 
 #include "nodes/expr/addr_expr.h"
 #include "nodes/expr/modify_expr.h"
+#include "nodes/expr/ne_expr.h"
 #include "nodes/expr/pointerplus_expr.h"
 #include "nodes/expr/return_expr.h"
 
@@ -77,4 +78,28 @@ void analyseReturnExpr(ReturnExprNode *node, const WalkItem &wi, WalkItem &wo)
     wo.isReturned = true;
 }
 
+void analyseNeExpr(NeExprNode *node, const WalkItem &wi, WalkItem &wo)
+{
+    // need atleast one arg for check
+    if (node->args.size() < 2 || !wi.isExpr || command == FindArgs)
+        return;
+
+    // PARM_DECL?
+    Node *node1 = skipNop(node->args[0]);
+    // INTEGER_CST?
+    Node *node2 = skipNop(node->args[1]);
+
+    // if (var != 0)
+    if (node1 &&
+        node2 &&
+        node1->nodeType == PARM_DECL &&
+        node2->nodeType == INTEGER_CST &&
+        wi.checkNullVars.find(node1->label) != wi.checkNullVars.end() &&
+        node2->label == "0")
+    {
+        wo.removeNullVars.insert(node1->label);
+        wo.checkNullVars.erase(node1->label);
+    }
+}
+
 }
diff --git a/src/analysis/expression.h b/src/analysis/expression.h
index de459a6..1360118 100644
--- a/src/analysis/expression.h
+++ b/src/analysis/expression.h
@@ -24,6 +24,7 @@
 
 struct AddrExprNode;
 struct ModifyExprNode;
+struct NeExprNode;
 struct PointerPlusExprNode;
 struct ReturnExprNode;
 struct WalkItem;
@@ -37,6 +38,8 @@ namespace Analysis
     void analyseAddrExpr(AddrExprNode *node, const WalkItem &wi, WalkItem &wo);
 
     void analyseReturnExpr(ReturnExprNode *node, const WalkItem &wi, WalkItem &wo);
+
+    void analyseNeExpr(NeExprNode *node, const WalkItem &wi, WalkItem &wo);
 }
 
 #endif // ANALYSIS_EXPRESSION_H
diff --git a/src/analysis/walkitem.h b/src/analysis/walkitem.h
index 04e14b9..29352c0 100644
--- a/src/analysis/walkitem.h
+++ b/src/analysis/walkitem.h
@@ -29,7 +29,8 @@ struct WalkItem
         checkNullVars(),
         removeNullVars(),
         stopWalking(false),
-        isReturned(false)
+        isReturned(false),
+        isExpr(false)
     {
     }
 
@@ -43,8 +44,9 @@ struct WalkItem
 
     std::set<std::string> checkNullVars;
     std::set<std::string> removeNullVars;
-    bool stopWalking;
-    bool isReturned;
+    bool stopWalking;   // stop walking on tree after this node
+    bool isReturned;    // set if return present in child nodes
+    bool isExpr;        // set if walking on expression for if other kind nodes
 };