ValueFlow: Set values to parameters to longjmp and setjmp (#4040)

* ValueFlow: Set values to parameters to longjmp and setjmp

* Format

Author: pfultz2

lib/forwardanalyzer.cpp

@@ -123,9 +123,13 @@ struct ForwardTraversal {
 
     template<class T, class F, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
     Progress traverseTok(T* tok, F f, bool traverseUnknown, T** out = nullptr) {
-        if (Token::Match(tok, "asm|goto|setjmp|longjmp"))
+        if (Token::Match(tok, "asm|goto"))
             return Break(Analyzer::Terminate::Bail);
-        else if (Token::simpleMatch(tok, "continue")) {
+        else if (Token::Match(tok, "setjmp|longjmp (")) {
+            // Traverse the parameters of the function before escaping
+            traverseRecursive(tok->next()->astOperand2(), f, traverseUnknown);
+            return Break(Analyzer::Terminate::Bail);
+        } else if (Token::simpleMatch(tok, "continue")) {
             if (loopEnds.empty())
                 return Break(Analyzer::Terminate::Escape);
             // If we are in a loop then jump to the end

test/testvalueflow.cpp

@@ -3486,6 +3486,12 @@ class TestValueFlow : public TestFixture {
                "    exit(x);\n"
                "}\n";
         ASSERT_EQUALS(true, testValueOfXKnown(code, 3U, 1));
+
+        code = "void f(jmp_buf env) {\n"
+               "    int x = 1;\n"
+               "    longjmp(env, x);\n"
+               "}\n";
+        ASSERT_EQUALS(true, testValueOfXKnown(code, 3U, 1));
     }
 
     void valueFlowForwardTernary() {