Fixed #4964 (printf format argument check only supports simple variables)

lib/checkio.cpp

@@ -555,9 +555,10 @@ void CheckIO::checkWrongPrintfScanfArguments()
                         }
 
                         // Perform type checks
-                        if (argListTok && Token::Match(argListTok->next(), "[,)]")) { // We can currently only check the type of arguments matching this simple pattern.
-                            const Variable *variableInfo = argListTok->variable();
-                            const Token* varTypeTok = variableInfo ? variableInfo->typeStartToken() : NULL;
+                        const Variable *variableInfo;
+                        const Token *varTypeTok;
+
+                        if (getArgumentInfo(argListTok, &variableInfo, &varTypeTok)) {
                             if (varTypeTok && varTypeTok->str() == "static")
                                 varTypeTok = varTypeTok->next();
 
@@ -735,6 +736,33 @@ void CheckIO::checkWrongPrintfScanfArguments()
     }
 }
 
+// We can currently only check the type of arguments matching these simple patterns:
+//   var
+//   var.var
+//   var[...]
+//
+/// @todo add more complex variables, lietrals, functions, and generic expressions
+
+bool CheckIO::getArgumentInfo(const Token * tok, const Variable **var, const Token **typeTok) const
+{
+    if (tok && (Token::Match(tok->next(), "[,)]") ||
+                Token::Match(tok->next(), ". %var% [,)]") ||
+                (Token::simpleMatch(tok->next(), "[") && Token::Match(tok->linkAt(1)->next(), "[,)]")))) {
+        if (tok->next()->str() == ".")
+            tok = tok->tokAt(2);
+
+        const Variable *variableInfo = tok->variable();
+        const Token *varTypeTok = variableInfo ? variableInfo->typeStartToken() : NULL;
+
+        *var = variableInfo;
+        *typeTok = varTypeTok;
+
+        return true;
+    }
+
+    return false;
+}
+
 void CheckIO::wrongPrintfScanfArgumentsError(const Token* tok,
         const std::string &functionName,
         unsigned int numFormat,

lib/checkio.h

@@ -70,6 +70,8 @@ public:
     void checkWrongPrintfScanfArguments();
 
 private:
+    bool getArgumentInfo(const Token *tok, const Variable **var, const Token **typeTok) const;
+
     // Reporting errors..
     void coutCerrMisusageError(const Token* tok, const std::string& streamName);
     void fflushOnInputStreamError(const Token *tok, const std::string &varname);

test/testio.cpp

@@ -793,6 +793,17 @@ private:
                       "[test.cpp:5]: (warning) %llu in format string (no. 1) requires an unsigned long long integer given in the argument list.\n"
                       "[test.cpp:6]: (warning) %lx in format string (no. 1) requires a long integer given in the argument list.\n"
                       "[test.cpp:7]: (warning) %llx in format string (no. 1) requires a long long integer given in the argument list.\n", errout.str());
+
+        check("class Foo {\n"
+              "    double d;\n"
+              "};\n"
+              "int a[10];\n"
+              "void foo(const Foo* foo) {\n"
+              "    printf(\"%d\", foo->d);\n"
+              "    printf(\"%f\", a[0]);\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:6]: (warning) %d in format string (no. 1) requires a signed integer given in the argument list.\n"
+                      "[test.cpp:7]: (warning) %f in format string (no. 1) requires a floating point number given in the argument list.\n", errout.str());
     }
 
     void testPosixPrintfScanfParameterPosition() { // #4900  - No support for parameters in format strings