Fixed #7668 (ValueFlow: return value from abs)

cfg/std.cfg

@@ -10,6 +10,7 @@
     <pure/>
     <noreturn>false</noreturn>
     <leak-ignore/>
+    <returnValue>arg1&gt;0?arg1:-arg1</returnValue>
     <arg nr="1">
       <not-uninit/>
       <not-bool/>
@@ -1584,6 +1585,7 @@ The obsolete function 'gets' is called. With 'gets' you'll get a buffer overrun
     <pure/>
     <noreturn>false</noreturn>
     <leak-ignore/>
+    <returnValue>arg1&gt;='0' &amp;&amp; arg1&lt;='9'</returnValue>
     <arg nr="1">
       <not-uninit/>
       <valid>0:255</valid>
@@ -3034,6 +3036,7 @@ The obsolete function 'gets' is called. With 'gets' you'll get a buffer overrun
     <pure/>
     <noreturn>false</noreturn>
     <leak-ignore/>
+    <returnValue>strlen(arg1)</returnValue>
     <arg nr="1">
       <not-null/>
       <not-uninit/>

lib/library.cpp

@@ -545,6 +545,8 @@ Library::Error Library::loadFunction(const tinyxml2::XMLElement * const node, co
             leakignore.insert(name);
         else if (functionnodename == "use-retval")
             _useretval.insert(name);
+        else if (functionnodename == "returnValue" && functionnode->GetText())
+            _returnValue[name] = functionnode->GetText();
         else if (functionnodename == "arg") {
             const char* argNrString = functionnode->Attribute("nr");
             if (!argNrString)
@@ -985,6 +987,14 @@ bool Library::isUseRetVal(const Token* ftok) const
             _useretval.find(getFunctionName(ftok)) != _useretval.end());
 }
 
+std::string Library::returnValue(const Token *ftok) const
+{
+    if (isNotLibraryFunction(ftok))
+        return std::string();
+    std::map<std::string, std::string>::const_iterator it = _returnValue.find(getFunctionName(ftok));
+    return it != _returnValue.end() ? it->second : std::string();
+}
+
 bool Library::isnoreturn(const Token *ftok) const
 {
     if (ftok->function() && ftok->function()->isAttributeNoreturn())

lib/library.h

@@ -165,6 +165,8 @@ public:
 
     bool isUseRetVal(const Token* ftok) const;
 
+    std::string returnValue(const Token *ftok) const;
+
     bool isnoreturn(const Token *ftok) const;
     bool isnotnoreturn(const Token *ftok) const;
 
@@ -478,6 +480,7 @@ private:
     std::map<std::string, AllocFunc> _dealloc; // deallocation functions
     std::set<std::string> _functions;
     std::map<std::string, bool> _noreturn; // is function noreturn?
+    std::map<std::string, std::string> _returnValue;
     std::set<std::string> _ignorefunction; // ignore functions/macros from a library (gtk, qt etc)
     std::map<std::string, bool> _reporterrors;
     std::map<std::string, bool> _processAfterCode;

lib/valueflow.cpp

@@ -407,7 +407,7 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
     }
 
     // Calculations..
-    else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp)) &&
+    else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp) || (parent->tokType() == Token::eLogicalOp)) &&
              parent->astOperand1() &&
              parent->astOperand2()) {
         const bool known = ((parent->astOperand1()->values.size() == 1U &&
@@ -503,11 +503,17 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
                         setTokenValue(parent, result);
                         break;
                     case '&':
+                        if (parent->str() == "&")
                             result.intvalue = value1->intvalue & value2->intvalue;
+                        else
+                            result.intvalue = value1->intvalue && value2->intvalue;
                         setTokenValue(parent, result);
                         break;
                     case '|':
+                        if (parent->str() == "|")
                             result.intvalue = value1->intvalue | value2->intvalue;
+                        else
+                            result.intvalue = value1->intvalue || value2->intvalue;
                         setTokenValue(parent, result);
                         break;
                     case '^':
@@ -2323,6 +2329,68 @@ static void valueFlowSwitchVariable(TokenList *tokenlist, SymbolDatabase* symbol
     }
 }
 
+static void setTokenValues(Token *tok, const std::list<ValueFlow::Value> &values)
+{
+    for (std::list<ValueFlow::Value>::const_iterator it = values.begin(); it != values.end(); ++it) {
+        const ValueFlow::Value &value = *it;
+        if (!value.tokvalue)
+            setTokenValue(tok, value);
+    }
+}
+
+static void valueFlowLibraryFunction(Token *tok, const std::string &returnValue, const Settings *settings)
+{
+    std::istringstream istr(returnValue);
+    TokenList tokenList(settings);
+    if (!tokenList.createTokens(istr))
+        return;
+
+    const Token *arg1 = tok->astOperand2();
+    while (arg1 && arg1->str() == ",")
+        arg1 = arg1->astOperand1();
+    if (Token::findsimplematch(tokenList.front(), "arg1") && !arg1)
+        return;
+
+    if (Token::simpleMatch(tokenList.front(), "strlen ( arg1 )") && arg1) {
+        for (std::list<ValueFlow::Value>::const_iterator it = arg1->values.begin(); it != arg1->values.end(); ++it) {
+            const ValueFlow::Value &value = *it;
+            if (value.tokvalue && value.tokvalue->tokType() == Token::eString) {
+                ValueFlow::Value retval(value); // copy all "inconclusive", "condition", etc attributes
+                // set return value..
+                retval.tokvalue = nullptr;
+                retval.intvalue = Token::getStrLength(value.tokvalue);
+                setTokenValue(tok, retval);
+            }
+        }
+        return;
+    }
+
+    // combine operators, set links, etc..
+    for (Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
+        if (Token::Match(tok2, "[!<>=] =")) {
+            tok2->str(tok2->str() + "=");
+            tok2->deleteNext();
+        }
+    }
+
+    // Evaluate expression
+    tokenList.createAst();
+    valueFlowNumber(&tokenList);
+    for (Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
+        if (tok2->str() == "arg1" && arg1) {
+            setTokenValues(tok2, arg1->values);
+        }
+    }
+
+    // Find result..
+    for (const Token *tok2 = tokenList.front(); tok2; tok2 = tok2->next()) {
+        if (!tok2->astParent() && !tok2->values.empty()) {
+            setTokenValues(tok, tok2->values);
+            return;
+        }
+    }
+}
+
 static void valueFlowSubFunction(TokenList *tokenlist, ErrorLogger *errorLogger, const Settings *settings)
 {
     for (Token *tok = tokenlist->front(); tok; tok = tok->next()) {
@@ -2330,8 +2398,13 @@ static void valueFlowSubFunction(TokenList *tokenlist, ErrorLogger *errorLogger,
             continue;
 
         const Function * const currentFunction = tok->function();
-        if (!currentFunction)
+        if (!currentFunction) {
+            // library function?
+            const std::string returnValue(settings->library.returnValue(tok));
+            if (!returnValue.empty())
+                valueFlowLibraryFunction(tok->next(), returnValue, settings);
             continue;
+        }
 
         // Function scope..
         const Scope * const functionScope = currentFunction->functionScope;