Make J9VMDllLoadInfo::fatalErrorStr 'const'

[dylanjtuttle]

Continue the effort to fix AIX warnings about converting string literals to mutable char pointers by adding a 'const' qualifier to J9VMDllLoadInfo::fatalErrorStr.

This PR contributes to (but does not close) #14859.

[dylanjtuttle]

Could you review when you get a chance Henry @hzongaro?

[keithc-ca]

fatalErrorStr needs to remain mutable

I don't think that's true. If the type of that field is changed to const char *, some other types would need to change with it, but I don't see any need for the casts proposed here.

[dylanjtuttle]

The reason I think(?) it needs to remain mutable is because I already tried making it const, but in openj9/runtime/vm/dllsup.c:L144 we use strcpy to copy the value of errorStr into info->fatalErrorStr and I got an error because strcpy requires the destination pointer to be mutable.

Is there a better way I could solve this problem? I am far from a C string expert and I agree that adding all of these casts doesn't seem like an ideal solution...

[keithc-ca]

Another local can be used in dllsup.c to receive the value returned by j9mem_allocate_memory() which can be given to strcpy() and assigned to fatalErrorStr.

I think a better solution is a single cast to char * (or perhaps void *) where the string is freed if FREE_ERROR_STRING is set.

[dylanjtuttle]

I see what you're saying Keith @keithc-ca, I've amended this PR accordingly. Thanks for the help!

[dylanjtuttle]

I'm getting an error about the PORTLIB macro that I'm not sure how to interpret:

In file included from /root/code/openj9-openjdk-jdk17/openj9/runtime/oti/j9.h:31,
                 from /root/code/openj9-openjdk-jdk17/openj9/runtime/jcl/common/vm_scar.c:31:
/root/code/openj9-openjdk-jdk17/openj9/runtime/jcl/common/vm_scar.c: In function 'setFatalErrorStringInDLLTableEntry':
/root/code/openj9-openjdk-jdk17/openj9/runtime/oti/j9port.h:56:18: error: 'privatePortLibrary' undeclared (first use in this function); did you mean 'GetPortLibrary'?
   56 | #define PORTLIB (privatePortLibrary)
      |                  ^~~~~~~~~~~~~~~~~~
/root/code/openj9-openjdk-jdk17/openj9/runtime/jcl/common/vm_scar.c:434:17: note: in expansion of macro 'PORTLIB'
  434 |   setErrorJ9dll(PORTLIB, loadInfo, errorString, FALSE);
      |                 ^~~~~~~
/root/code/openj9-openjdk-jdk17/openj9/runtime/oti/j9port.h:56:18: note: each undeclared identifier is reported only once for each function it appears in
   56 | #define PORTLIB (privatePortLibrary)
      |                  ^~~~~~~~~~~~~~~~~~
/root/code/openj9-openjdk-jdk17/openj9/runtime/jcl/common/vm_scar.c:434:17: note: in expansion of macro 'PORTLIB'
  434 |   setErrorJ9dll(PORTLIB, loadInfo, errorString, FALSE);
      |                 ^~~~~~~

Is there a problem with using PORTLIB in vm_scar.c? It gets used in a few other places.

[keithc-ca]

I'm getting an error about the PORTLIB macro that I'm not sure how to interpret:

You'll need to use one of the PORT_ACCESS_FROM_xx macros. For example, the first error is addressed by adding in the body of the if statement:

    PORT_ACCESS_FROM_JAVAVM(vm);

[dylanjtuttle]

I've added the PORT_ACCESS_FROM_xx macros, as well as a function pointer to allow access to setErrorJ9dll in certain places.

[keithc-ca]

Jenkins test sanity aix,alinux64 jdk17

[keithc-ca]

@hzongaro Could you please add your review?

[hzongaro]

Looks good. Thanks, @dylanjtuttle, for all your work on this pull request, and @keithc-ca, for all your thoughtful, thorough review!