Fixed danmar#6871 (False positive uninitvar - pointer to uninitialized char[])

danmar · danmar · commit e71ab703561d · 2015-08-08T14:52:46.000+02:00
diff --git a/lib/checkuninitvar.cpp b/lib/checkuninitvar.cpp
@@ -218,6 +218,17 @@ static bool isVariableUsed(const Token *tok, const Variable& var)
         return false;
     if (tok->isConstOp())
         return isVariableUsed(tok->astOperand1(),var) || isVariableUsed(tok->astOperand2(),var);
+    if (var.isArray()) {
+        const Token *parent = tok->astParent();
+        while (Token::Match(parent, "[?:]"))
+            parent = parent->astParent();
+        // no dereference, then array is not "used"
+        if (!Token::Match(parent, "*|["))
+            return false;
+        const Token *parent2 = parent->astParent();
+        // TODO: handle function calls. There is a TODO assertion in TestUninitVar::uninitvar_arrays
+        return !parent2 || parent2->isConstOp() || (parent2->str() == "=" && parent2->astOperand2() == parent);
+    }
     return (tok->varId() == var.declarationId());
 }
 
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
@@ -1254,6 +1254,26 @@ class TestUninitVar : public TestFixture {
                        "}");
         ASSERT_EQUALS("", errout.str());
 
+        // array usage in ?: (tests that the isVariableUsed() works)
+        checkUninitVar("void f() {\n"
+                       "    char a[10], *p;\n"
+                       "    p = c?a:0;\n"
+                       "}");
+        ASSERT_EQUALS("", errout.str());
+
+        checkUninitVar("void f() {\n"
+                       "    char a[10], c;\n"
+                       "    c = *(x?a:0);\n"
+                       "}");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: a\n", errout.str());
+
+        checkUninitVar("void f() {\n"
+                       "    char a[10], c;\n"
+                       "    strcpy(dest, x?a:\"\");\n"
+                       "}");
+        TODO_ASSERT_EQUALS("error", "", errout.str());
+
+        // passing array to library functions
         checkUninitVar("void f()\n"
                        "{\n"
                        "    char c[50] = \"\";\n"
