RFR (S): JDK-8056242: Add function to return structured information about loaded libraries.

[Staffan Larsen]

Thanks for doing these changes. Here are comments on the new version:

os_windows.cpp
- Why not rename enumerate_modules() to get_loaded_modules_info() and update all caller to use the new unified method?
- At the same time, can we get rid of the pid parameter to enumerate_modules()? It looks like all callers set it the same value.
- nit: looks like the <= and > used to be aligned in these if-statements:
1380    if (base_addr     <= pmod->addr &&
1381        top_address > pmod->addr) {
1436    if (base_addr     <= (address)_locate_jvm_dll &&
1437        top_address > (address)_locate_jvm_dll) {

os_solaris.cpp
- I think print_dll_info() should be re-implemented in terms of get_loaded_modules_info() so that there is only one implementation of this logic.
- get_loaded_modules_info() references os::print_dll_info() which looks like a mistake?

os_linux.cpp
- get_loaded_modules_info() could use some blank lines to split it up into logical chunks of code.
- I think “r” is enough for fopen() - ie drop the “t” 
- Can the fgets+sscanf be replaced by a call to fscanf? That would avoid the ‘line’ variable and any possible problems of lines not fitting into the space allocated.

os_bsd.cpp
- Maybe add a comment about module_top_addr being 0?

Thanks,
/Staffan


On 1 sep 2014, at 14:05, Fredrik Arvidsson <fredrik.arvidsson at oracle.com> wrote:

> Hi
> 
> Here is an updated version of the patch. Thanks for the comments.
> 
> Webrev: http://cr.openjdk.java.net/~farvidsson/8056242/webrev.01/index.html
> 
> /Fredrik
> 
> On 2014-08-28 16:21, Staffan Larsen wrote:
>> Hi Fredrik,
>> 
>> A couple of comments:
>> - I would prefer if the new callback was unified with the one that exists on Windows so that we have only on callback-based API for listing dynamic libraries.
>> - If you do that, then would you also clean up enumerate_modules() on windows to get rid of the non-NT support?
>> - Smaller: I think “address” is a better type to use instead of “u8”.
>> 
>> Thanks
>> /Staffan
>> 
>> 
>> On 28 aug 2014, at 15:54, Fredrik Arvidsson <fredrik.arvidsson at oracle.com> wrote:
>> 
>>> Hi
>>> 
>>> Please help me review this small enhancement.
>>> 
>>> Webrev: http://cr.openjdk.java.net/~farvidsson/8056242/webrev.00/index.html
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8056242
>>> 
>>> Cheers
>>> /F
>