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8166188: G1 Needs pre barrier on dereference of weak JNI handles

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Add low tag to jweaks and G1 barrier for jweak loads.

Co-authored-by: Martin Doerr <martin.doerr@sap.com>
Co-authored-by: Volker Simonis <volker.simonis@sap.com>
Reviewed-by: mgerdin, mdoerr, pliden, dlong, dcubed, coleenp, aph, tschatzl
This commit is contained in:
Kim Barrett 2017-02-15 22:19:13 -05:00
parent 6a5e6f2ae1
commit 28477cf493
37 changed files with 1061 additions and 429 deletions
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32
hotspot/src/cpu/x86/vm/macroAssembler_x86.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -5129,6 +5129,36 @@ void MacroAssembler::vxorps(XMMRegister dst, XMMRegister nds, AddressLiteral src
}
void MacroAssembler::resolve_jobject(Register value,
Register thread,
Register tmp) {
assert_different_registers(value, thread, tmp);
Label done, not_weak;
testptr(value, value);
jcc(Assembler::zero, done); // Use NULL as-is.
testptr(value, JNIHandles::weak_tag_mask); // Test for jweak tag.
jcc(Assembler::zero, not_weak);
// Resolve jweak.
movptr(value, Address(value, -JNIHandles::weak_tag_value));
verify_oop(value);
#if INCLUDE_ALL_GCS
if (UseG1GC) {
g1_write_barrier_pre(noreg /* obj */,
value /* pre_val */,
thread /* thread */,
tmp /* tmp */,
true /* tosca_live */,
true /* expand_call */);
}
#endif // INCLUDE_ALL_GCS
jmp(done);
bind(not_weak);
// Resolve (untagged) jobject.
movptr(value, Address(value, 0));
verify_oop(value);
bind(done);
}
//////////////////////////////////////////////////////////////////////////////////
#if INCLUDE_ALL_GCS