--- a/src/hotspot/cpu/x86/jniFastGetField_x86_64.cpp Fri Oct 12 12:37:13 2018 +0530
+++ b/src/hotspot/cpu/x86/jniFastGetField_x86_64.cpp Fri Oct 12 03:51:02 2018 -0400
@@ -35,9 +35,6 @@
#define BUFFER_SIZE 30*wordSize
-// Instead of issuing lfence for LoadLoad barrier, we create data dependency
-// between loads, which is more efficient than lfence.
-
// Common register usage:
// rax/xmm0: result
// c_rarg0: jni env
@@ -77,12 +74,6 @@
__ mov (robj, c_rarg1);
__ testb (rcounter, 1);
__ jcc (Assembler::notZero, slow);
-
- __ xorptr(robj, rcounter);
- __ xorptr(robj, rcounter); // obj, since
- // robj ^ rcounter ^ rcounter == robj
- // robj is data dependent on rcounter.
-
__ mov (roffset, c_rarg2);
__ shrptr(roffset, 2); // offset
@@ -103,12 +94,7 @@
default: ShouldNotReachHere();
}
- // create data dependency on rax
- __ lea(rcounter_addr, counter);
- __ xorptr(rcounter_addr, rax);
- __ xorptr(rcounter_addr, rax);
- __ cmpl (rcounter, Address(rcounter_addr, 0));
-
+ __ cmp32 (rcounter, counter);
__ jcc (Assembler::notEqual, slow);
__ ret (0);
@@ -178,11 +164,6 @@
__ testb (rcounter, 1);
__ jcc (Assembler::notZero, slow);
- __ xorptr(robj, rcounter);
- __ xorptr(robj, rcounter); // obj, since
- // robj ^ rcounter ^ rcounter == robj
- // robj is data dependent on rcounter.
-
// Both robj and rtmp are clobbered by try_resolve_jobject_in_native.
BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
bs->try_resolve_jobject_in_native(masm, /* jni_env */ c_rarg0, robj, rtmp, slow);
@@ -198,13 +179,7 @@
case T_DOUBLE: __ movdbl (xmm0, Address(robj, roffset, Address::times_1)); break;
default: ShouldNotReachHere();
}
-
- __ lea(rcounter_addr, counter);
- __ movdq (rax, xmm0);
- // counter address is data dependent on xmm0.
- __ xorptr(rcounter_addr, rax);
- __ xorptr(rcounter_addr, rax);
- __ cmpl (rcounter, Address(rcounter_addr, 0));
+ __ cmp32 (rcounter, counter);
__ jcc (Assembler::notEqual, slow);
__ ret (0);