Mercurial > hg > truffle
comparison src/share/vm/runtime/arguments.cpp @ 237:1fdb98a17101
6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes
| author | coleenp |
|---|---|
| date | Sat, 19 Jul 2008 17:38:22 -0400 |
| parents | d1605aabd0a1 |
| children | b727c32788a9 d95b224e9f17 ef72a36b968e |
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| 235:9c2ecc2ffb12 | 237:1fdb98a17101 |
|---|---|
| 1174 // field offset to determine free list chunk markers. | 1174 // field offset to determine free list chunk markers. |
| 1175 // Check that UseCompressedOops can be set with the max heap size allocated | 1175 // Check that UseCompressedOops can be set with the max heap size allocated |
| 1176 // by ergonomics. | 1176 // by ergonomics. |
| 1177 if (MaxHeapSize <= max_heap_for_compressed_oops()) { | 1177 if (MaxHeapSize <= max_heap_for_compressed_oops()) { |
| 1178 if (FLAG_IS_DEFAULT(UseCompressedOops)) { | 1178 if (FLAG_IS_DEFAULT(UseCompressedOops)) { |
| 1179 // Leave compressed oops off by default. Uncomment | 1179 FLAG_SET_ERGO(bool, UseCompressedOops, true); |
| 1180 // the following line to return it to default status. | |
| 1181 // FLAG_SET_ERGO(bool, UseCompressedOops, true); | |
| 1182 } | 1180 } |
| 1183 } else { | 1181 } else { |
| 1184 if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) { | 1182 if (UseCompressedOops && !FLAG_IS_DEFAULT(UseCompressedOops)) { |
| 1185 // If specified, give a warning | 1183 // If specified, give a warning |
| 1186 if (UseConcMarkSweepGC){ | 1184 if (UseConcMarkSweepGC){ |