Fix #10157: FP invalidFunctionArg with memset (if-branch should be discarded) (#7080)

Author: ludviggunne

lib/checkfunctions.cpp

@@ -107,6 +107,7 @@ void CheckFunctions::invalidFunctionUsage()
     const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
     for (const Scope *scope : symbolDatabase->functionScopes) {
         for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
+            tok = skipUnreachableBranch(tok);
             if (!Token::Match(tok, "%name% ( !!)"))
                 continue;
             const Token * const functionToken = tok;

test/testfunctions.cpp

@@ -55,6 +55,9 @@ class TestFunctions : public TestFixture {
         TEST_CASE(invalidFunctionUsage1);
         TEST_CASE(invalidFunctionUsageStrings);
 
+        // Invalid function argument
+        TEST_CASE(invalidFunctionArg1);
+
         // Math function usage
         TEST_CASE(mathfunctionCall_fmod);
         TEST_CASE(mathfunctionCall_sqrt);
@@ -755,6 +758,21 @@ class TestFunctions : public TestFixture {
         ASSERT_EQUALS("[test.c:1]: (error) Invalid puts() argument nr 1. A nul-terminated string is required.\n", errout_str());
     }
 
+    void invalidFunctionArg1() {
+        const Settings settingsUnix32 = settingsBuilder(settings).platform(Platform::Unix32).build();
+        check("int main() {\n"
+              "    char tgt[7];\n"
+              "    char src[7+1] = \"7777777\";\n"
+              "    if (sizeof tgt <= sizeof src) {\n"
+              "        memmove(&tgt, &src, sizeof tgt);\n"
+              "    } else {\n"
+              "        memmove(&tgt, &src, sizeof src);\n"
+              "        memset(&tgt + sizeof src, ' ', sizeof tgt - sizeof src);\n"
+              "    }\n"
+              "}\n", false, &settingsUnix32);
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void mathfunctionCall_sqrt() {
         // sqrt, sqrtf, sqrtl
         check("void foo()\n"