RFR: 8343756: CAN_SHOW_REGISTERS_ON_ASSERT for Windows [v4]

[Johan Sjölen]

On Thu, 14 Nov 2024 13:53:19 GMT, Markus Grönlund <mgronlun at openjdk.org> wrote:

>> Greetings,
>> 
>> This enhancement adds register printouts on asserts or guarantees into the hs_err_pid.log error reporting files for Windows.
>> 
>> Additionally, it saves an accurate EXCEPTION_RECORD into the  hs_err_pid.mdmp file, also for asserts or guarantees, so the assertion context is now easily accessible in Windbg using .ecxr.
>> 
>> For more details on this enhancement, please see the JIRA issue.
>> 
>> Testing: Tier 1,2,3, jdk_jfr
>> 
>> Thanks
>> Markus
>
> Markus Grönlund has updated the pull request incrementally with one additional commit since the last revision:
> 
>   extended test

Hi,

This code looks good to me, with a small comment.

src/hotspot/os/posix/os_posix.cpp line 2219:

> 2217:   // In the copied version, fpregs should point to the copied contents.
> 2218:   // Sanity check: fpregs should point into the context.
> 2219:   if ((address)((const ucontext_t*)ucVoid)->uc_mcontext.fpregs > (address)ucVoid) {

Maybe check that the address is larger than ucVoid but smaller than `ucVoid + sizeof(ucontext_t)`?

```c++
  const ucontext_t* uc = (const ucontext_t*)ucVoid;
  if (uc->uc_mcontext.fpregs >= (uintptr_t)uc && 
      uc->uc_mcontext.fpregs < (uintptr_t)(uc + 1)) {
  }

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

Marked as reviewed by jsjolen (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/21994#pullrequestreview-2458582801
PR Review Comment: https://git.openjdk.org/jdk/pull/21994#discussion_r1856703906