Add more read barriers for JNI roots.
To make it possible to concurrently scan the JNI global roots (that
is, the roots visited by JavaVMExt::VisitRoots()), add read barriers
to the indirect reference table and the reference table.
Also, add read barriers to the jmethodID/jfieldID decode routines
(ScopedObjectAccessAlreadyRunnable::DecodeField/DecodeMethod) so that
we can concurrently handle (encoded) fields and methods.
Bug: 12687968
Change-Id: I3df4e4e622a572ff0ea8d44b2dc70a4d6b3ba058
diff --git a/runtime/indirect_reference_table.h b/runtime/indirect_reference_table.h
index 5b3ed68..b3a855d 100644
--- a/runtime/indirect_reference_table.h
+++ b/runtime/indirect_reference_table.h
@@ -27,6 +27,7 @@
#include "mem_map.h"
#include "object_callbacks.h"
#include "offsets.h"
+#include "read_barrier.h"
namespace art {
namespace mirror {
@@ -215,6 +216,7 @@
}
mirror::Object** operator*() {
+ // This does not have a read barrier as this is used to visit roots.
return &table_[i_];
}
@@ -298,6 +300,7 @@
return segment_state_.parts.topIndex;
}
+ // Note IrtIterator does not have a read barrier as it's used to visit roots.
IrtIterator begin() {
return IrtIterator(table_, 0, Capacity());
}
@@ -333,7 +336,7 @@
* The object pointer itself is subject to relocation in some GC
* implementations, so we shouldn't really be using it here.
*/
- IndirectRef ToIndirectRef(const mirror::Object* /*o*/, uint32_t tableIndex) const {
+ IndirectRef ToIndirectRef(uint32_t tableIndex) const {
DCHECK_LT(tableIndex, 65536U);
uint32_t serialChunk = slot_data_[tableIndex].serial;
uintptr_t uref = serialChunk << 20 | (tableIndex << 2) | kind_;
@@ -368,9 +371,8 @@
std::unique_ptr<MemMap> table_mem_map_;
// Mem map where we store the extended debugging info.
std::unique_ptr<MemMap> slot_mem_map_;
- // bottom of the stack. If a JNI weak global table, do not directly
- // access the object references in this as they are weak roots. Use
- // Get() that has a read barrier.
+ // bottom of the stack. Do not directly access the object references
+ // in this as they are roots. Use Get() that has a read barrier.
mirror::Object** table_;
/* bit mask, ORed into all irefs */
IndirectRefKind kind_;