Mercurial > hg > truffle
comparison src/share/vm/opto/parse3.cpp @ 11164:fcf521c3fbc6
8007898: Incorrect optimization of Memory Barriers in Matcher::post_store_load_barrier()
Summary: generate one "fat" membar instead of set of barriers for volitile store
Reviewed-by: roland
| author | kvn |
|---|---|
| date | Fri, 12 Jul 2013 14:03:10 -0700 |
| parents | 6f3fd5150b67 |
| children | edb5ab0f3fe5 |
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| 11163:c90c698831d7 | 11164:fcf521c3fbc6 |
|---|---|
| 292 } | 292 } |
| 293 | 293 |
| 294 // If reference is volatile, prevent following volatiles ops from | 294 // If reference is volatile, prevent following volatiles ops from |
| 295 // floating up before the volatile write. | 295 // floating up before the volatile write. |
| 296 if (is_vol) { | 296 if (is_vol) { |
| 297 // First place the specific membar for THIS volatile index. This first | 297 insert_mem_bar(Op_MemBarVolatile); // Use fat membar |
| 298 // membar is dependent on the store, keeping any other membars generated | |
| 299 // below from floating up past the store. | |
| 300 int adr_idx = C->get_alias_index(adr_type); | |
| 301 insert_mem_bar_volatile(Op_MemBarVolatile, adr_idx, store); | |
| 302 | |
| 303 // Now place a membar for AliasIdxBot for the unknown yet-to-be-parsed | |
| 304 // volatile alias indices. Skip this if the membar is redundant. | |
| 305 if (adr_idx != Compile::AliasIdxBot) { | |
| 306 insert_mem_bar_volatile(Op_MemBarVolatile, Compile::AliasIdxBot, store); | |
| 307 } | |
| 308 | |
| 309 // Finally, place alias-index-specific membars for each volatile index | |
| 310 // that isn't the adr_idx membar. Typically there's only 1 or 2. | |
| 311 for( int i = Compile::AliasIdxRaw; i < C->num_alias_types(); i++ ) { | |
| 312 if (i != adr_idx && C->alias_type(i)->is_volatile()) { | |
| 313 insert_mem_bar_volatile(Op_MemBarVolatile, i, store); | |
| 314 } | |
| 315 } | |
| 316 } | 298 } |
| 317 | 299 |
| 318 // If the field is final, the rules of Java say we are in <init> or <clinit>. | 300 // If the field is final, the rules of Java say we are in <init> or <clinit>. |
| 319 // Note the presence of writes to final non-static fields, so that we | 301 // Note the presence of writes to final non-static fields, so that we |
| 320 // can insert a memory barrier later on to keep the writes from floating | 302 // can insert a memory barrier later on to keep the writes from floating |