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6991197: G1: specialize deal_with_reference() for narrowOop*

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Clean up and slightly optimize reference handling from the GC reference task queue. Since we never push partial array chunks as narrowOop* we can manually specialize the code so that some code can be optimized away.

Reviewed-by: tonyp, brutisso, stefank
This commit is contained in:
Thomas Schatzl 2014-01-31 09:57:50 +01:00
parent 0bc1701ea0
commit 90c553c06f
1 changed files with 17 additions and 4 deletions
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21
hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.hpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2014, 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
@ -86,13 +86,26 @@ public:
#define G1_PARTIAL_ARRAY_MASK 0x2
template <class T> inline bool has_partial_array_mask(T* ref) {
inline bool has_partial_array_mask(oop* ref) {
return ((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) == G1_PARTIAL_ARRAY_MASK;
}
template <class T> inline T* set_partial_array_mask(T obj) {
// We never encode partial array oops as narrowOop*, so return false immediately.
// This allows the compiler to create optimized code when popping references from
// the work queue.
inline bool has_partial_array_mask(narrowOop* ref) {
assert(((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) != G1_PARTIAL_ARRAY_MASK, "Partial array oop reference encoded as narrowOop*");
return false;
}
// Only implement set_partial_array_mask() for regular oops, not for narrowOops.
// We always encode partial arrays as regular oop, to allow the
// specialization for has_partial_array_mask() for narrowOops above.
// This means that unintentional use of this method with narrowOops are caught
// by the compiler.
inline oop* set_partial_array_mask(oop obj) {
assert(((uintptr_t)(void *)obj & G1_PARTIAL_ARRAY_MASK) == 0, "Information loss!");
return (T*) ((uintptr_t)(void *)obj | G1_PARTIAL_ARRAY_MASK);
return (oop*) ((uintptr_t)(void *)obj | G1_PARTIAL_ARRAY_MASK);
}
template <class T> inline oop clear_partial_array_mask(T* ref) {