Fix issue 9709: ValueFlow: variable value is not known (cppcheck-opensource#2643)

pfultz2 · web-flow · commit d123279fc13e · 2020-05-14T14:10:32.000+02:00
diff --git a/lib/programmemory.cpp b/lib/programmemory.cpp
@@ -199,6 +199,10 @@ static void fillProgramMemoryFromAssignments(ProgramMemory& pm, const Token* tok
                 else
                     pm.setUnknown(vartok->varId());
             }
+        } else if (!setvar && Token::Match(tok2, "%var% !!=") && isVariableChanged(tok2, 0, nullptr, true)) {
+            const Token *vartok = tok2;
+            if (!pm.hasValue(vartok->varId()))
+                pm.setUnknown(vartok->varId());
         }
 
         if (tok2->str() == "{") {
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
@@ -3366,6 +3366,18 @@ class TestCondition : public TestFixture {
               "    if (!x) {}\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        // #9709
+        check("void f(int a) {\n"
+              "    bool ok = false;\n"
+              "    const char * r = nullptr;\n"
+              "    do_something(&r);\n"
+              "    if (r != nullptr)\n"
+              "        ok = a != 0;\n"
+              "    if (ok) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
     }
 
     void alwaysTrueInfer() {

Original file line number	Diff line number	Diff line change
`@@ -199,6 +199,10 @@ static void fillProgramMemoryFromAssignments(ProgramMemory& pm, const Token* tok`
`199`	`199`	`else`
`200`	`200`	`pm.setUnknown(vartok->varId());`
`201`	`201`	`}`
	`202`	`+ } else if (!setvar && Token::Match(tok2, "%var% !!=") && isVariableChanged(tok2, 0, nullptr, true)) {`
	`203`	`+ const Token *vartok = tok2;`
	`204`	`+ if (!pm.hasValue(vartok->varId()))`
	`205`	`+ pm.setUnknown(vartok->varId());`
`202`	`206`	`}`
`203`	`207`
`204`	`208`	`if (tok2->str() == "{") {`