archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-28 07:14:30 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

6378256: Performance problem with System.identityHashCode in client compiler

Browse source 
Enabled C1 optimization to try pull out hashCode from object header, before calling into the VM.

Reviewed-by: dlong, roland, thartmann
This commit is contained in:
Rahul Raghavan 2016-02-17 12:24:53 +01:00 • committed by Tobias Hartmann
parent 05730d99ba
commit 2c5e376d98
5 changed files with 125 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

25
hotspot/src/cpu/sparc/vm/sharedRuntime_sparc.cpp
View file

@ -2015,23 +2015,33 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
int vep_offset = ((intptr_t)__ pc()) - start;
#ifdef COMPILER1
if (InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) {
// Object.hashCode can pull the hashCode from the header word
// instead of doing a full VM transition once it's been computed.
// Since hashCode is usually polymorphic at call sites we can't do
// this optimization at the call site without a lot of work.
if ((InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) || (method->intrinsic_id() == vmIntrinsics::_identityHashCode)) {
// Object.hashCode, System.identityHashCode can pull the hashCode from the
// header word instead of doing a full VM transition once it's been computed.
// Since hashCode is usually polymorphic at call sites we can't do this
// optimization at the call site without a lot of work.
Label slowCase;
Register receiver = O0;
Label done;
Register obj_reg = O0;
Register result = O0;
Register header = G3_scratch;
Register hash = G3_scratch; // overwrite header value with hash value
Register mask = G1; // to get hash field from header
// Unlike for Object.hashCode, System.identityHashCode is static method and
// gets object as argument instead of the receiver.
if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
assert(method->is_static(), "method should be static");
// return 0 for null reference input
__ br_null(obj_reg, false, Assembler::pn, done);
__ delayed()->mov(obj_reg, hash);
}
// Read the header and build a mask to get its hash field. Give up if the object is not unlocked.
// We depend on hash_mask being at most 32 bits and avoid the use of
// hash_mask_in_place because it could be larger than 32 bits in a 64-bit
// vm: see markOop.hpp.
__ ld_ptr(receiver, oopDesc::mark_offset_in_bytes(), header);
__ ld_ptr(obj_reg, oopDesc::mark_offset_in_bytes(), header);
__ sethi(markOopDesc::hash_mask, mask);
__ btst(markOopDesc::unlocked_value, header);
__ br(Assembler::zero, false, Assembler::pn, slowCase);
@ -2054,6 +2064,7 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
__ delayed()->nop();
// leaf return.
__ bind(done);
__ retl();
__ delayed()->mov(hash, result);
__ bind(slowCase);