Mercurial > hg > truffle
diff src/share/vm/opto/parse1.cpp @ 14702:d4dd5204c0aa
Merge
author | ehelin |
---|---|
date | Fri, 14 Mar 2014 13:27:18 +0100 |
parents | 3edd4a71588b |
children | 92aa6797d639 |
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--- a/src/share/vm/opto/parse1.cpp Fri Mar 14 09:18:39 2014 +0100 +++ b/src/share/vm/opto/parse1.cpp Fri Mar 14 13:27:18 2014 +0100 @@ -391,6 +391,8 @@ _depth = 1 + (caller->has_method() ? caller->depth() : 0); _wrote_final = false; _wrote_volatile = false; + _wrote_stable = false; + _wrote_fields = false; _alloc_with_final = NULL; _entry_bci = InvocationEntryBci; _tf = NULL; @@ -908,26 +910,35 @@ Node* iophi = _exits.i_o(); _exits.set_i_o(gvn().transform(iophi)); - // On PPC64, also add MemBarRelease for constructors which write - // volatile fields. As support_IRIW_for_not_multiple_copy_atomic_cpu - // is set on PPC64, no sync instruction is issued after volatile - // stores. We want to quarantee the same behaviour as on platforms - // with total store order, although this is not required by the Java - // memory model. So as with finals, we add a barrier here. - if (wrote_final() PPC64_ONLY(|| (wrote_volatile() && method()->is_initializer()))) { - // This method (which must be a constructor by the rules of Java) - // wrote a final. The effects of all initializations must be - // committed to memory before any code after the constructor - // publishes the reference to the newly constructor object. - // Rather than wait for the publication, we simply block the - // writes here. Rather than put a barrier on only those writes - // which are required to complete, we force all writes to complete. - // - // "All bets are off" unless the first publication occurs after a - // normal return from the constructor. We do not attempt to detect - // such unusual early publications. But no barrier is needed on - // exceptional returns, since they cannot publish normally. - // + // Figure out if we need to emit the trailing barrier. The barrier is only + // needed in the constructors, and only in three cases: + // + // 1. The constructor wrote a final. The effects of all initializations + // must be committed to memory before any code after the constructor + // publishes the reference to the newly constructed object. Rather + // than wait for the publication, we simply block the writes here. + // Rather than put a barrier on only those writes which are required + // to complete, we force all writes to complete. + // + // 2. On PPC64, also add MemBarRelease for constructors which write + // volatile fields. As support_IRIW_for_not_multiple_copy_atomic_cpu + // is set on PPC64, no sync instruction is issued after volatile + // stores. We want to guarantee the same behavior as on platforms + // with total store order, although this is not required by the Java + // memory model. So as with finals, we add a barrier here. + // + // 3. Experimental VM option is used to force the barrier if any field + // was written out in the constructor. + // + // "All bets are off" unless the first publication occurs after a + // normal return from the constructor. We do not attempt to detect + // such unusual early publications. But no barrier is needed on + // exceptional returns, since they cannot publish normally. + // + if (method()->is_initializer() && + (wrote_final() || + PPC64_ONLY(wrote_volatile() ||) + (AlwaysSafeConstructors && wrote_fields()))) { _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final()); #ifndef PRODUCT if (PrintOpto && (Verbose || WizardMode)) { @@ -937,6 +948,19 @@ #endif } + // Any method can write a @Stable field; insert memory barriers after + // those also. If there is a predecessor allocation node, bind the + // barrier there. + if (wrote_stable()) { + _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final()); +#ifndef PRODUCT + if (PrintOpto && (Verbose || WizardMode)) { + method()->print_name(); + tty->print_cr(" writes @Stable and needs a memory barrier"); + } +#endif + } + for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) { // transform each slice of the original memphi: mms.set_memory(_gvn.transform(mms.memory()));