RFR: 8357396: Refactor nmethod::make_not_entrant to use Enum instead of "const char*" [v2]

[Aleksey Shipilev]

On Tue, 3 Jun 2025 05:40:09 GMT, Cesar Soares Lucas <cslucas at openjdk.org> wrote:

>> Please review this refactor to transform the reasons for making an nmethod not entrant from `const char*` into enum values.
>> 
>> Tested on Linux x64 with JTREG tier1-3 in fastdebug and release mode.
>
> Cesar Soares Lucas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address PR feedback: modify emum to be scoped.

Looks conceptually fine. Cosmetics:

src/hotspot/share/code/nmethod.hpp line 498:

> 496: 
> 497: 
> 498:   static const char* NMethodChangeReason_to_string(NMethodChangeReason reason) {

Uh, use a switch:


 switch(reason) {
    case C1_deoptimize: return "C1 deoptimized";
    case C1_codepatch:  return "C1 code patch";
    ...
    default:
       assert(false, "Unhandled reason");
       return "Unknown";
 }

src/hotspot/share/jvmci/jvmciEnv.cpp line 1755:

> 1753: 
> 1754: 
> 1755: void JVMCIEnv::invalidate_nmethod_mirror(JVMCIObject mirror, bool deoptimize, nmethod::NMethodChangeReason statusReason, JVMCI_TRAPS) {

Suggestion:

void JVMCIEnv::invalidate_nmethod_mirror(JVMCIObject mirror, bool deoptimize, nmethod::NMethodChangeReason change_reason, JVMCI_TRAPS) {

src/hotspot/share/jvmci/jvmciEnv.hpp line 465:

> 463:   // If `deoptimize` is true, the nmethod is immediately deoptimized.
> 464:   // The HotSpotNmethod.address field is zero upon returning.
> 465:   void invalidate_nmethod_mirror(JVMCIObject mirror, bool deoptimze, nmethod::NMethodChangeReason statusReason, JVMCI_TRAPS);

Suggestion:

  void invalidate_nmethod_mirror(JVMCIObject mirror, bool deoptimize, nmethod::NMethodChangeReason change_reason, JVMCI_TRAPS);

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

PR Review: https://git.openjdk.org/jdk/pull/25338#pullrequestreview-2891309126
PR Review Comment: https://git.openjdk.org/jdk/pull/25338#discussion_r2123138594
PR Review Comment: https://git.openjdk.org/jdk/pull/25338#discussion_r2123153641
PR Review Comment: https://git.openjdk.org/jdk/pull/25338#discussion_r2123152309