added command-line option `--valueflow-max-iterations` to control amount of valueflow iterations / also log debug warning when iterations are being exceeded (#4557)

cli/cmdlineparser.cpp

@@ -915,6 +915,21 @@ bool CmdLineParser::parseFromArgs(int argc, const char* const argv[])
                 }
             }
 
+            else if (std::strncmp(argv[i], "--valueflow-max-iterations=", 27) == 0) {
+                long tmp;
+                try {
+                    tmp = std::stol(argv[i] + 27);
+                } catch (const std::invalid_argument &) {
+                    printError("argument to '--valueflow-max-iteration' is invalid.");
+                    return false;
+                }
+                if (tmp < 0) {
+                    printError("argument to '--valueflow-max-iteration' needs to be at least 0.");
+                    return false;
+                }
+                mSettings->valueFlowMaxIterations = static_cast<std::size_t>(tmp);
+            }
+
             else if (std::strcmp(argv[i], "-v") == 0 || std::strcmp(argv[i], "--verbose") == 0)
                 mSettings->verbose = true;
 

lib/settings.cpp

@@ -66,6 +66,7 @@ Settings::Settings()
     relativePaths(false),
     reportProgress(false),
     showtime(SHOWTIME_MODES::SHOWTIME_NONE),
+    valueFlowMaxIterations(4),
     verbose(false),
     xml(false),
     xml_version(2)

lib/settings.h

@@ -351,6 +351,9 @@ public:
     /** @brief forced includes given by the user */
     std::list<std::string> userIncludes;
 
+    /** @brief the maximum iterations of valueflow (--valueflow-max-iterations=T) */
+    std::size_t valueFlowMaxIterations;
+
     /** @brief Is --verbose given? */
     bool verbose;
 

lib/valueflow.cpp

@@ -8986,7 +8986,7 @@ void ValueFlow::setValues(TokenList *tokenlist, SymbolDatabase* symboldatabase,
     const std::uint64_t stopTime = getValueFlowStopTime(settings);
 
     std::size_t values = 0;
-    std::size_t n = 4;
+    std::size_t n = settings->valueFlowMaxIterations;
     while (n > 0 && values != getTotalValues(tokenlist)) {
         values = getTotalValues(tokenlist);
 
@@ -9048,6 +9048,18 @@ void ValueFlow::setValues(TokenList *tokenlist, SymbolDatabase* symboldatabase,
         n--;
     }
 
+    if (settings->debugwarnings) {
+        if (n == 0 && values != getTotalValues(tokenlist)) {
+            ErrorMessage errmsg({},
+                                emptyString,
+                                Severity::debug,
+                                "ValueFlow maximum iterations exceeded",
+                                "valueFlowMaxIterations",
+                                Certainty::normal);
+            errorLogger->reportErr(errmsg);
+        }
+    }
+
     if (std::time(nullptr) < stopTime)
         valueFlowDynamicBufferSize(tokenlist, symboldatabase, settings);
 

test/testcmdlineparser.cpp

@@ -153,6 +153,11 @@ private:
         TEST_CASE(clang);
         TEST_CASE(clang2);
         TEST_CASE(clangInvalid);
+        TEST_CASE(valueFlowMaxIterations);
+        TEST_CASE(valueFlowMaxIterations2);
+        TEST_CASE(valueFlowMaxIterationsInvalid);
+        TEST_CASE(valueFlowMaxIterationsInvalid2);
+        TEST_CASE(valueFlowMaxIterationsInvalid3);
 
         // TODO
         // Disabling these tests since they use relative paths to the
@@ -1260,6 +1265,45 @@ private:
         ASSERT_EQUALS("cppcheck: error: unrecognized command line option: \"--clang-foo\".\n", GET_REDIRECT_OUTPUT);
     }
 
+    void valueFlowMaxIterations() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--valueflow-max-iterations=0"};
+        settings.valueFlowMaxIterations = -1;
+        ASSERT(defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS(0, settings.valueFlowMaxIterations);
+        ASSERT_EQUALS("", GET_REDIRECT_OUTPUT);
+    }
+
+    void valueFlowMaxIterations2() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--valueflow-max-iterations=11"};
+        settings.valueFlowMaxIterations = -1;
+        ASSERT(defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS(11, settings.valueFlowMaxIterations);
+        ASSERT_EQUALS("", GET_REDIRECT_OUTPUT);
+    }
+
+    void valueFlowMaxIterationsInvalid() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--valueflow-max-iterations"};
+        ASSERT(!defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("cppcheck: error: unrecognized command line option: \"--valueflow-max-iterations\".\n", GET_REDIRECT_OUTPUT);
+    }
+
+    void valueFlowMaxIterationsInvalid2() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--valueflow-max-iterations=seven"};
+        ASSERT(!defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("cppcheck: error: argument to '--valueflow-max-iteration' is invalid.\n", GET_REDIRECT_OUTPUT);
+    }
+
+    void valueFlowMaxIterationsInvalid3() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--valueflow-max-iterations=-1"};
+        ASSERT(!defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("cppcheck: error: argument to '--valueflow-max-iteration' needs to be at least 0.\n", GET_REDIRECT_OUTPUT);
+    }
+
     /*
         void ignorepaths1() {
             REDIRECT;