ValueFlow: sizeof string and char literals (#2285)

lib/valueflow.cpp

@@ -1232,6 +1232,20 @@ static Token * valueFlowSetConstantValue(Token *tok, const Settings *settings, b
                     setTokenValue(tok->next(), value, settings);
                 }
             }
+        } else if (tok2->tokType() == Token::eString) {
+            size_t sz = Token::getStrSize(tok2, settings);
+            if (sz > 0) {
+                ValueFlow::Value value(sz);
+                value.setKnown();
+                setTokenValue(const_cast<Token *>(tok->next()), value, settings);
+            }
+        } else if (tok2->tokType() == Token::eChar) {
+            size_t sz = ValueFlow::getSizeOf(*tok2->valueType(), settings);
+            if (sz > 0) {
+                ValueFlow::Value value(sz);
+                value.setKnown();
+                setTokenValue(tok->next(), value, settings);
+            }
         } else if (!tok2->type()) {
             const ValueType &vt = ValueType::parseDecl(tok2,settings);
             const size_t sz = ValueFlow::getSizeOf(vt, settings);

test/testvalueflow.cpp

@@ -813,6 +813,19 @@ private:
         CHECK("int", settings.sizeof_int);
         CHECK("long", settings.sizeof_long);
         CHECK("wchar_t", settings.sizeof_wchar_t);
+
+        // string/char literals
+        CHECK("\"asdf\"", 5);
+        CHECK("L\"asdf\"", 5 * settings.sizeof_wchar_t);
+        CHECK("u8\"asdf\"", 5); // char8_t
+        CHECK("u\"asdf\"", 5 * 2); // char16_t
+        CHECK("U\"asdf\"", 5 * 4); // char32_t
+        CHECK("'a'", 1U);
+        CHECK("'ab'", settings.sizeof_int);
+        CHECK("L'a'", settings.sizeof_wchar_t);
+        CHECK("u8'a'", 1U); // char8_t
+        CHECK("u'a'", 2U); // char16_t
+        CHECK("U'a'", 4U); // char32_t
 #undef CHECK
 
         // array size