[lworld] RFR: 8327150: [lworld] Update C1 to support new value construction scheme from JEP 401

[Frederic Parain]

On Mon, 4 Mar 2024 13:36:58 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Fix value creation in C1, remove the old special node for value creation and out everything under the NewInstance node.
>> There's also a fix in can_be_inline_klass() method that was causing a wrong behavior for acmp.
>
> src/hotspot/share/c1/c1_Compiler.cpp line 260:
> 
>> 258:     if (PrintCFGToFile) {  // borrowing flag for JDK build
>> 259:       tty->print_cr("Starting C1 compilation of %s.%s", method->holder()->name()->as_utf8(), method->name()->as_utf8());
>> 260:     }
> 
> Why do you need this?

Oops, remaining of tracing during debugging. Removed.

> src/hotspot/share/c1/c1_Instruction.hpp line 2068:
> 
>> 2066:       // FIXME: Removal of NewInlineTypeInstance instruction makes those assert hard to write
>> 2067:       // assert(x->as_NewInlineTypeInstance() == nullptr || y->type() == objectNull, "Sanity check");
>> 2068:       // assert(y->as_NewInlineTypeInstance() == nullptr || x->type() == objectNull, "Sanity check");
> 
> Let's remove these checks for now.

OK

> src/hotspot/share/c1/c1_Runtime1.cpp line 373:
> 
>> 371:   h->initialize(CHECK);
>> 372:   oop obj = nullptr;
>> 373:   if(h->is_empty_inline_type()) {
> 
> Suggestion:
> 
>   if (h->is_empty_inline_type()) {

Fixed.

> src/hotspot/share/c1/c1_Runtime1.cpp line 374:
> 
>> 372:   oop obj = nullptr;
>> 373:   if(h->is_empty_inline_type()) {
>> 374:     assert(h->is_inline_klass(), "Sanity check");
> 
> Below `InlineKlass::cast` will already assert that.

Removed.

> src/hotspot/share/c1/c1_Runtime1.cpp line 375:
> 
>> 373:   if(h->is_empty_inline_type()) {
>> 374:     assert(h->is_inline_klass(), "Sanity check");
>> 375:     assert(InlineKlass::cast(h)->default_value() != nullptr, "");
> 
> This can be moved below and check `obj != nullptr` directly.

Fixed.

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

PR Review Comment: https://git.openjdk.org/valhalla/pull/1029#discussion_r1511223684
PR Review Comment: https://git.openjdk.org/valhalla/pull/1029#discussion_r1511222524
PR Review Comment: https://git.openjdk.org/valhalla/pull/1029#discussion_r1511218396
PR Review Comment: https://git.openjdk.org/valhalla/pull/1029#discussion_r1511221526
PR Review Comment: https://git.openjdk.org/valhalla/pull/1029#discussion_r1511221856