From 2d92f1ff6a48ce0a8645ba691c9e80199754a2be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <danielm77@spray.se>
Date: Mon, 10 Jan 2011 19:35:06 +0100
Subject: [PATCH] Fixed #2442 (False positive: Memory leak when function
 returns in 'if' instead of 'else if')

---
 lib/checkmemoryleak.cpp | 22 +++++++++++++++++++++-
 test/testmemleak.cpp    |  4 ++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/lib/checkmemoryleak.cpp b/lib/checkmemoryleak.cpp
index c004edc05..278653877 100644
--- a/lib/checkmemoryleak.cpp
+++ b/lib/checkmemoryleak.cpp
@@ -838,6 +838,10 @@ Token *CheckMemoryLeakInFunction::getcode(const Token *tok, std::list<const Toke
 {
     Token *rethead = 0, *rettail = 0;
 
+    // variables whose value depends on if(!var). If one of these variables
+    // is used in a if-condition then generate "ifv" instead of "if".
+    std::set<unsigned int> extravar;
+
     // The first token should be ";"
     rethead = new Token(0);
     rethead->str(";");
@@ -1084,10 +1088,22 @@ Token *CheckMemoryLeakInFunction::getcode(const Token *tok, std::list<const Toke
                 else if (Token::simpleMatch(tok, "if (") && notvar(tok->tokAt(2), varid, true))
                 {
                     addtoken(&rettail, tok, "if(!var)");
+
+                    // parse the if-body.
+                    // if a variable is assigned then add variable to "extravar".
+                    for (const Token *tok2 = tok->next()->link()->tokAt(2); tok2; tok2 = tok2->next())
+                    {
+                        if (tok2->str() == "{")
+                            tok2 = tok2->link();
+                        else if (tok2->str() == "}")
+                            break;
+                        else if (Token::Match(tok2, "%var% ="))
+                            extravar.insert(tok2->varId());
+                    }
                 }
                 else
                 {
-                    // Check if the condition depends on var somehow..
+                    // Check if the condition depends on var or extravar somehow..
                     bool dep = false;
                     int innerParlevel = 0;
                     for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
@@ -1138,6 +1154,10 @@ Token *CheckMemoryLeakInFunction::getcode(const Token *tok, std::list<const Toke
                                 break;
                             }
                         }
+                        if (tok2->varId() && extravar.find(tok2->varId()) != extravar.end())
+                        {
+                            dep = true;
+                        }
                     }
 
                     if (Token::Match(tok, "if ( ! %varid% &&", varid))
diff --git a/test/testmemleak.cpp b/test/testmemleak.cpp
index 05b04e3c4..ef900c103 100644
--- a/test/testmemleak.cpp
+++ b/test/testmemleak.cpp
@@ -425,6 +425,10 @@ private:
         ASSERT_EQUALS(";;use;if{}", getcode("char *s; if (x(&s)) { }", "s"));
         ASSERT_EQUALS(";;use;if{}", getcode("char *s; if (!s || x(&s)) { }", "s"));
 
+        // if (ticket #2442)
+        ASSERT_EQUALS(";;;;if(!var){;}ifv{}", getcode("char *s; int x = 0; if (!s) { x = 2; } if (x) { }", "s"));
+        ASSERT_EQUALS(";;;;if(!var){;}if{}", getcode("char *s; int x = 0; if (!s) { x = 2; } if (y) { }", "s"));
+
         // switch..
         ASSERT_EQUALS(";;switch{case;;break;};", getcode("char *s; switch(a){case 1: break;};", "s"));