False positives with bitfields and a modified platform integer size

[Chris Engel]

We are running into an issue where it appears cppcheck is not calculating the size of an object correctly and is then calling out passedByValue

Here is the sample object with a bunch of different variations that all lead to an 8B value . Some work and others don't as denoted by the comments.

class   testObject
{
  public:
    enum Base
    {
      Val1 = 0x0000
    };

    #if 0  // This fails
    Base                 base:32;
    Base                 ext:16;
    uint16_t             value;
    #elif 0 // This works
    Base                 base:32;
    uint32_t             value;
    #elif 0 // This works
    uint32_t             base;
    Base                 ext:16;
    uint16_t             value;
    #elif 0 // This fails
    Base                 base:32;
    Base                 ext:16;
    uint16_t             value;
    #elif 0 // This fails
    Base                 base1:16;
    Base                 base2:16;
    Base                 ext:16;
    uint16_t             value;
    #elif 0 // This works
    Base                 base1:32;
    Base                 base2:32;
    #elif 0 // This works
    Base                 base1:32;
    uint16_t             value;
    uint16_t             value2;
    #elif 1 // This fails
    Base                 base1:16;
    Base                 base2:16;
    uint16_t             value;
    uint16_t             value2;

    #endif
};

I'm running cppcheck 2.17.1 as follows:

$ cppcheck -q --enable=performance --language=c++ --template=gcc --platform=./platform.xml test.C
test.C:51:23: warning: Function parameter 'tParm' should be passed by const reference. [passedByValue]
bool func1(testObject tParm) {
                      ^

And our platform file has only one change from the unit64-unsigned.xml platform file provided by cppcheck

$ diff platform.xml unix64-unsigned.xml 
8c8
<     <int>8</int>
---
>     <int>4</int>

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/13850