Add way to track variables if to it was assigned function result.

6 files changed, 129 insertions, 11 deletions

diff --git a/src/analysis/collections.cpp b/src/analysis/collections.cpp
index 3d4f5e2..a475acc 100644
--- a/src/analysis/collections.cpp
+++ b/src/analysis/collections.cpp
@@ -137,13 +137,26 @@ void removeNeedCheckNullVarsSet(WalkItem &wi, std::set<std::string> &vars)
     }
 }
 
-void addNullVar(WalkItem &wi,
-                const std::string &var)
+void addUnknownVar(WalkItem &wi,
+                   const std::string &var)
 {
+    wi.knownVars.insert(var);
+    wi.knownNullVars.erase(var);
+    wi.knownNonNullVars.erase(var);
     wi.addNullVars.insert(var);
     wi.removeNullVars.erase(var);
 }
 
+void addNonNullVar(WalkItem &wi,
+                   const std::string &var)
+{
+    wi.knownVars.insert(var);
+    wi.knownNullVars.erase(var);
+    wi.knownNonNullVars.insert(var);
+    wi.addNullVars.erase(var);
+    wi.removeNullVars.insert(var);
+}
+
 // link var to parent. (type var = parent)
 void addLinkedVar(WalkItem &wi,
                   std::string parent,
diff --git a/src/analysis/collections.h b/src/analysis/collections.h
index 738b8a8..388a50f 100644
--- a/src/analysis/collections.h
+++ b/src/analysis/collections.h
@@ -33,8 +33,11 @@ namespace Analysis
     void addNeedCheckNullVars(WalkItem &wi,
                               WalkItem &wo);
 
-    void addNullVar(WalkItem &wi,
-                    const std::string &var);
+    void addUnknownVar(WalkItem &wi,
+                       const std::string &var);
+
+    void addNonNullVar(WalkItem &wi,
+                       const std::string &var);
 
     void addLinkedVar(WalkItem &wi,
                       std::string parent,
diff --git a/src/analysis/expression.cpp b/src/analysis/expression.cpp
index 53f13c5..7c5194e 100644
--- a/src/analysis/expression.cpp
+++ b/src/analysis/expression.cpp
@@ -83,6 +83,29 @@ std::string getVariableName(Node *node)
     return "";
 }
 
+bool isPointerArg(Node *node)
+{
+    if (!node)
+        return false;
+
+    node = skipNop(node);
+    if (!node)
+        return false;
+    if (node == PARM_DECL)
+    {
+        ParmDeclNode *decl = static_cast<ParmDeclNode*>(node);
+        if (skipNop(decl->declType) == POINTER_TYPE)
+            return true;
+    }
+    else if (node == VAR_DECL)
+    {
+        VarDeclNode *var = static_cast<VarDeclNode*>(node);
+        if (skipNop(var->varType) == POINTER_TYPE)
+            return true;
+    }
+    return false;
+}
+
 // return variable name in format object->field for component node
 std::string getComponentRefVariable(Node *node)
 {
@@ -137,7 +160,13 @@ void analyseModifyExpr(ModifyExprNode *node, const WalkItem &wi, WalkItem &wo)
         {
             if (var2.empty())
             {   // have var1 only (var1 = UNKNOWN)
-                removeVar(wo, var1);
+                bool handled(false);
+                if (node->args[1] == CALL_EXPR && isPointerArg(arg))
+                {
+                    handled = handleSetVarToFunction(var1, node->args[1], wo);
+                }
+                if (!handled)
+                    removeVar(wo, var1);
             }
             else
             {   // have var1 and var2 (var1 = var2)
@@ -704,6 +733,37 @@ void handleSetVarDecl(Node *node,
     }
 }
 
+bool handleSetVarToFunction(const std::string &var,
+                            Node *node2,
+                            WalkItem &wo)
+{
+    CallExprNode *call = static_cast<CallExprNode*>(node2);
+    if (call->function != ADDR_EXPR)
+        return false;
+    AddrExprNode *addr = static_cast<AddrExprNode*>(call->function);
+    if (!addr ||
+        addr->args.empty() ||
+        addr->args[0] != FUNCTION_DECL)
+    {
+        return false;
+    }
+    FunctionDeclNode *func = static_cast<FunctionDeclNode*>(addr->args[0]);
+    removeVar(wo, var);
+    if (!func->functionType)
+        return false;
+
+    if (findTreeListPurpose(static_cast<TreeListNode*>(func->functionType->attribute),
+        "returns_nonnull"))
+    {   // function have attribute returns_nonnull. This mean result cant be null
+        addNonNullVar(wo, var);
+    }
+    else
+    {   // function not have attribute returns_nonnull. This mean result can be null
+        addUnknownVar(wo, var);
+    }
+    return true;
+}
+
 void handleSetVar(Node *node1,
                   Node *node2,
                   const WalkItem &wi,
@@ -712,11 +772,21 @@ void handleSetVar(Node *node1,
     // var1 = var2
     const std::string var1 = getVariableName(node1);
     const std::string var2 = getVariableName(node2);
-    if (var1.empty() || var2.empty())
+    if (var1.empty())
         return;
-    if (isNotIn(var2, wi.knownVars))
+    if (var2.empty())
+    {
+        node2 = skipNop(node2);
+        if (node2 == CALL_EXPR && isPointerArg(node1))
+            handleSetVarToFunction(var1, node2, wo);
         return;
-    addLinkedVar(wo, var2, var1);
+    }
+    else
+    {
+        if (isNotIn(var2, wi.knownVars))
+            return;
+        addLinkedVar(wo, var2, var1);
+    }
 }
 
 // field = var
diff --git a/src/analysis/expression.h b/src/analysis/expression.h
index ccba0ca..8d8bb8c 100644
--- a/src/analysis/expression.h
+++ b/src/analysis/expression.h
@@ -94,6 +94,10 @@ namespace Analysis
                           WalkItem &wo);
 
     std::string getComponentRefVariable(Node *node);
+
+    bool handleSetVarToFunction(const std::string &var,
+                                Node *node2,
+                                WalkItem &wo);
 }
 
 #endif // ANALYSIS_EXPRESSION_H
diff --git a/src/analysis/function.cpp b/src/analysis/function.cpp
index e9de29a..8bb9566 100644
--- a/src/analysis/function.cpp
+++ b/src/analysis/function.cpp
@@ -57,6 +57,19 @@ void getFunctionArgTypes(FunctionDeclNode *node,
     }
 }
 
+bool findTreeListPurpose(TreeListNode *list,
+                         const std::string &name)
+{
+    FOR_TREE_LIST(list)
+    {
+        if (list->purpose && list->purpose->label == name)
+        {
+            return true;
+        }
+    }
+    return false;
+}
+
 // find in TREE_LIST purpose with given label and get value
 TreeListNode *findTreeListPurposeValue(TreeListNode *list,
                                        const std::string &name)
@@ -71,15 +84,24 @@ TreeListNode *findTreeListPurposeValue(TreeListNode *list,
     return nullptr;
 }
 
+TreeListNode *findFunctionDeclAttribute(FunctionDeclNode *node,
+                                        const std::string &name)
+{
+    // function not have type
+    if (!node->functionType)
+        return nullptr;
+    return findTreeListPurposeValue(
+        static_cast<TreeListNode*>(node->functionType->attribute),
+        name);
+}
+
 void getFunctionParamsNonNullAttributes(FunctionDeclNode *node,
                                         std::set<int> &arr)
 {
     // function not have type
     if (!node->functionType)
         return;
-    TreeListNode *list = findTreeListPurposeValue(
-        static_cast<TreeListNode*>(node->functionType->attribute),
-        "nonnull");
+    TreeListNode *list = findFunctionDeclAttribute(node, "nonnull");
     // no attribute nonnull
     if (!list)
         return;
diff --git a/src/analysis/function.h b/src/analysis/function.h
index f7e0a66..9358efe 100644
--- a/src/analysis/function.h
+++ b/src/analysis/function.h
@@ -38,6 +38,12 @@ namespace Analysis
 
     void getFunctionParamsNonNullAttributes(FunctionDeclNode *node,
                                             std::set<int> &arr);
+
+    TreeListNode *findFunctionDeclAttribute(FunctionDeclNode *node,
+                                            const std::string &name);
+
+    bool findTreeListPurpose(TreeListNode *list,
+                             const std::string &name);
 }
 
 #endif // ANALYSIS_FUNCTION_H