Weak symbols in codeprover

We use the gcc attributing in order to mark functions weak in libraries. That way projects including these libraries can overwrite the content of that weak function with custom content.

e.g. usage in a library:

void __attribute__((weak)) foo (void)
{
}

The codeprover (polyspace-code-prover-nodesktop) doesn't seem to understand this attribute, as it is gcc specific implementation.

Does codeprover provide some alternative syntax for this?

I can see a valid alternative, but that would be quiet intrusive for our libraries:

#ifndef NO_FOO_IMPLEMENTATION
void foo(void)
{
}
#endif

So what does codeprover support in order to mark a function as weak, over writable by other implementation.

Answer 1

[Alexandre De Barros]

Hello,

when you write "The codeprover doesn't seem to understand this attribute", do you mean that you have a compilation error?

If yes, I can't reproduce it when selecting "gnu4.6" as the "compiler" in Polyspace (version R2017a).

What version of Polyspace do you use, and what is the value associated to the -compiler option?

Best regards,

Alexandre

[Stein Heselmans]

using R2016a here, and gnu3.4 dialect

I don't have a compilation error. Codeprover just seems to ignore this attribute and use the function as a normal (non-weak) symbol.

In the end the codeprover 'linker' complains about the symbol being defined twice.

file1.c, line 40: Error: procedure xxxxxx multiply defined
| previously defined at file2.c:20

[Alexandre De Barros]

A workaround is to make these functions static inside the Polyspace verification.

Hence, multiple definitions will be allowed.

Could you contact the support? They will tell you how to do that.

Best regards,

Alexandre

[Stein Heselmans]

I guess those static function would more or less be the same as my proposed workaround (#ifndef NO_FOO_IMPLEMENTATION). I'ld rather go with that