tree 062f296ec594a4bf075aaac19c07cfc9cb2fd86e
parent 8f21748bf127012947ed48c40948df3f2d9c85ef
author Ulya Trafimovich <skvadrik@google.com> 1626174962 +0100
committer Ulya Trafimovich <skvadrik@google.com> 1626454400 +0100

x86_64: Implement VarHandle.getAndSet for fields.

The implementation is based on XCHG instruction, so it cannot be reused
for other getAnd* methods.

Benchmarks improvements (using benchmarks provided by
https://android-review.googlesource.com/1420959):

  benchmark                           before   after
  --------------------------------------------------
  GetAndSetStaticFieldInt             2.449    0.018
  GetAndSetStaticFieldString          2.818    0.014
  GetAndSetFieldInt                   2.728    0.012
  GetAndSetFieldString                3.002    0.014
  GetAndSetAcquireStaticFieldInt      2.438    0.007
  GetAndSetAcquireStaticFieldString   2.811    0.010
  GetAndSetAcquireFieldInt            2.726    0.007
  GetAndSetAcquireFieldString         2.998    0.010
  GetAndSetReleaseStaticFieldInt      2.436    0.007
  GetAndSetReleaseStaticFieldString   2.813    0.010
  GetAndSetReleaseFieldInt            2.730    0.007
  GetAndSetReleaseFieldString         2.997    0.010

Bug: 65872996

Test: lunch aosp_cf_x86_64_phone-userdebug \
  && art/test.py --host -r -t 712-varhandle-invocations --64
Test: Repeat with ART_USE_READ_BARRIER=false.
Test: Repeat with ART_HEAP_POISONING=true.
Change-Id: I77bdf6d4b940d90b0efe499cab335e5a0fa5ca4a