RFR: JDK-8306672: support offset in dll_address_to_library_name on AIX

[Thomas Stuefe]

On Thu, 27 Apr 2023 14:30:18 GMT, JoKern65 <duke at openjdk.org> wrote:

> So far the offset return reference parameter was not supported on AIX, but always set to -1. This could be improved, it was already supported on other OS platforms like Linux.

Hi Joachim,

nice to see you here :-)

Change is mostly good, small nits remain. You may want to adjust copyright years in the file headers. The rule we follow is
- adjust Oracle's copyright year always if needed (changing the last year to 2023)
- adjust SAPs (or whatever company you work for) copyright too
- leave other copyrights alone.
Note: porting_aix has no Oracle copyrights since nothing in that codebase hat been derived from the OpenJDK.

Cheers, Thomas

src/hotspot/os/aix/os_aix.cpp line 1086:

> 1084:   }
> 1085:   if (offset != nullptr) {
> 1086:     *offset = addr - base;

Maybe add a sanity check that addr >= base and <= (base + INT_MAX). If it never should happen, an assert is fine, otherwise handled at runtime.

src/hotspot/os/aix/os_aix.cpp line 1089:

> 1087:   }
> 1088: 
> 1089:   return true;

Style nits: 

- no space after (
- for booleans (and only those), the abridged style "if (!xxx)" is preferred

(for this and other things, see https://github.com/openjdk/jdk/blob/a471510d33c3a21c6df4cf868042fa8d822002e7/doc/hotspot-style.md)

And yes, a lot of older existing code does not follow these, but newer additions should.

src/hotspot/os/aix/porting_aix.hpp line 91:

> 89:     address pc,                      // [in] program counter
> 90:     char* p_name, size_t namelen,    // [out] module name
> 91:     address* p_base                  // [out] module name

comment copy paste error?

-------------

Changes requested by stuefe (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13692#pullrequestreview-1404370887
PR Review Comment: https://git.openjdk.org/jdk/pull/13692#discussion_r1179364386
PR Review Comment: https://git.openjdk.org/jdk/pull/13692#discussion_r1179357293
PR Review Comment: https://git.openjdk.org/jdk/pull/13692#discussion_r1179369935