On Tue, 22 Oct 2024 16:22:20 GMT, Roman Kennke <rken...@openjdk.org> wrote:
>> Roman Kennke has updated the pull request incrementally with two additional
>> commits since the last revision:
>>
>> - Update copyright
>> - Avoid assert/endless-loop in JFR code
>
> @egahlin / @mgronlun could you please review the JFR parts of this PR? One
> change is for getting the right prototype header, the other is for avoiding
> an endless loop/assert in a corner case.
@rkennke can you include this small update for s390x as well:
```diff
diff --git a/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
b/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
index 0f7e5c9f457..476e3d5daa4 100644
--- a/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
+++ b/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
@@ -174,8 +174,11 @@ void C1_MacroAssembler::try_allocate(
void C1_MacroAssembler::initialize_header(Register obj, Register klass,
Register len, Register Rzero, Register t1) {
assert_different_registers(obj, klass, len, t1, Rzero);
if (UseCompactObjectHeaders) {
- z_lg(t1, Address(klass, in_bytes(Klass::prototype_header_offset())));
- z_stg(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
+ z_mvc(
+ Address(obj, oopDesc::mark_offset_in_bytes()), /* move to */
+ Address(klass, in_bytes(Klass::prototype_header_offset())), /* move
from */
+ sizeof(markWord) /* how much to move */
+ );
} else {
load_const_optimized(t1, (intx)markWord::prototype().value());
z_stg(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
diff --git a/src/hotspot/cpu/s390/c2_MacroAssembler_s390.cpp
b/src/hotspot/cpu/s390/c2_MacroAssembler_s390.cpp
index 378d5e4cfe1..c5713161bf9 100644
--- a/src/hotspot/cpu/s390/c2_MacroAssembler_s390.cpp
+++ b/src/hotspot/cpu/s390/c2_MacroAssembler_s390.cpp
@@ -46,7 +46,7 @@ void C2_MacroAssembler::load_narrow_klass_compact_c2(Register
dst, Address src)
// The incoming address is pointing into obj-start + klass_offset_in_bytes.
We need to extract
// obj-start, so that we can load from the object's mark-word instead.
z_lg(dst, src.plus_disp(-oopDesc::klass_offset_in_bytes()));
- z_srlg(dst, dst, markWord::klass_shift); // TODO: could be z_sra
+ z_srlg(dst, dst, markWord::klass_shift);
}
//------------------------------------------------------
diff --git a/src/hotspot/cpu/s390/templateTable_s390.cpp
b/src/hotspot/cpu/s390/templateTable_s390.cpp
index 3cb1aba810d..5b8f7a20478 100644
--- a/src/hotspot/cpu/s390/templateTable_s390.cpp
+++ b/src/hotspot/cpu/s390/templateTable_s390.cpp
@@ -3980,8 +3980,11 @@ void TemplateTable::_new() {
// Initialize object header only.
__ bind(initialize_header);
if (UseCompactObjectHeaders) {
- __ z_lg(tmp, Address(iklass,
in_bytes(Klass::prototype_header_offset())));
- __ z_stg(tmp, Address(RallocatedObject,
oopDesc::mark_offset_in_bytes()));
+ __ z_mvc(
+ Address(RallocatedObject, oopDesc::mark_offset_in_bytes()), //
move to
+ Address(iklass, in_bytes(Klass::prototype_header_offset())), //
move from
+ sizeof(markWord) // how much to move
+ );
} else {
__ store_const(Address(RallocatedObject,
oopDesc::mark_offset_in_bytes()),
(long) markWord::prototype().value());
-------------
PR Comment: https://git.openjdk.org/jdk/pull/20677#issuecomment-2444180131
