RFR: 8326378: [PPC64] CodeEntryAlignment too large

[Martin Doerr]

I'd like to save space in the code cache. No performance regression observed. See JBS issue for more details.

Old:

[Instructions begin]
 ;; N1181: #	out( B1 ) <- BLOCK HEAD IS JUNK  Freq: 1
  0x00007fff7cbda880:   nop                                 ;   {no_reloc}
  0x00007fff7cbda884:   nop
  0x00007fff7cbda888:   nop
  0x00007fff7cbda88c:   nop
  0x00007fff7cbda890:   nop
  0x00007fff7cbda894:   nop
  0x00007fff7cbda898:   nop
  0x00007fff7cbda89c:   nop
  0x00007fff7cbda8a0:   nop
  0x00007fff7cbda8a4:   nop
  0x00007fff7cbda8a8:   nop
  0x00007fff7cbda8ac:   nop
  0x00007fff7cbda8b0:   nop
  0x00007fff7cbda8b4:   nop
  0x00007fff7cbda8b8:   nop
  0x00007fff7cbda8bc:   nop
  0x00007fff7cbda8c0:   nop
  0x00007fff7cbda8c4:   nop
  0x00007fff7cbda8c8:   nop
  0x00007fff7cbda8cc:   nop
  0x00007fff7cbda8d0:   nop
  0x00007fff7cbda8d4:   nop
  0x00007fff7cbda8d8:   nop
  0x00007fff7cbda8dc:   nop
  0x00007fff7cbda8e0:   nop
  0x00007fff7cbda8e4:   nop
  0x00007fff7cbda8e8:   nop
  0x00007fff7cbda8ec:   nop
  0x00007fff7cbda8f0:   nop
[Entry Point]
  # {method} {0x00007fff407064e8} 'bogus_test' '()V' in 'TestAlloc'
  #           [sp+0x90]  (sp of caller)
  0x00007fff7cbda8f4:   lwz     r11,8(r3)
  0x00007fff7cbda8f8:   ld      r12,8(r19)
  0x00007fff7cbda8fc:   td      3,r11,r12               ;trap: ic miss check
[Verified Entry Point]


New:

[Instructions begin]
 ;; N1181: #	out( B1 ) <- BLOCK HEAD IS JUNK  Freq: 1
  0x00007fff802f8380:   nop                                 ;   {no_reloc}
  0x00007fff802f8384:   nop
  0x00007fff802f8388:   nop
  0x00007fff802f838c:   nop
  0x00007fff802f8390:   nop
  0x00007fff802f8394:   nop
  0x00007fff802f8398:   nop
  0x00007fff802f839c:   nop
  0x00007fff802f83a0:   nop
  0x00007fff802f83a4:   nop
  0x00007fff802f83a8:   nop
  0x00007fff802f83ac:   nop
  0x00007fff802f83b0:   nop
[Entry Point]
  # {method} {0x00007fff487064e8} 'bogus_test' '()V' in 'TestAlloc'
  #           [sp+0x90]  (sp of caller)
  0x00007fff802f83b4:   lwz     r11,8(r3)
  0x00007fff802f83b8:   ld      r12,8(r19)
  0x00007fff802f83bc:   td      3,r11,r12               ;trap: ic miss check
[Verified Entry Point]

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

Commit messages:
 - 8326378: [PPC64] CodeEntryAlignment too large

Changes: https://git.openjdk.org/jdk/pull/17939/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17939&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8326378
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17939.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17939/head:pull/17939

PR: https://git.openjdk.org/jdk/pull/17939