[lworld] RFR: Merge jdk [v2]

[Frederic Parain]

On Thu, 28 Sep 2023 08:10:07 GMT, David Simms <dsimms at openjdk.org> wrote:

>> Merge jdk-22+9
>
> David Simms has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Deferred test issues

Changes requested by fparain (Committer).

src/hotspot/cpu/x86/templateTable_x86.cpp line 3713:

> 3711:   load_resolved_field_entry(noreg, cache, rax, rbx, rdx);
> 3712:   // RBX: field offset, RCX: RAX: TOS, RDX: flags
> 3713:   __ movl(rscratch2, rdx);  // saving flags for is_flat test

It is dangerous to save the value in a scratch register and not using it immediately. In the current state of the code, there's no corruption of this register. But pop_and_check_object() below can produce a lot of code when verifying the oop, and if this code is modified and starts to use rschratch2, corruption will happen.
Suggested change:

load_resolved_field_entry(noreg, cache, rax, rbx, rdx);
__ pop(rax);

// Get object from stack
pop_and_check_object(rcx);

const Address field(rcx, rbx, Address::times_1);

// Check for volatile store
__ movl(rscratch2, rdx);     // preserving flags for is_flat test
__ testl(rscratch2, rscratch2);
__ jcc(Assembler::zero, notVolatile);

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

PR Review: https://git.openjdk.org/valhalla/pull/930#pullrequestreview-1649424730
PR Review Comment: https://git.openjdk.org/valhalla/pull/930#discussion_r1340495242