Use iterators "before" the use node in HUserRecord<>.
Create a new template class IntrusiveForwardList<> that
mimicks std::forward_list<> except that all allocations
are handled externally. This is essentially the same as
boost::intrusive::slist<> but since we're not using Boost
we have to reinvent the wheel.
Use the new container to replace the HUseList and use the
iterators to "before" use nodes in HUserRecord<> to avoid
the extra pointer to the previous node which was used
exclusively for removing nodes from the list. This reduces
the size of the HUseListNode by 25%, 32B to 24B in 64-bit
compiler, 16B to 12B in 32-bit compiler. This translates
directly to overall memory savings for the 64-bit compiler
but due to rounding up of the arena allocations to 8B, we
do not get any improvement in the 32-bit compiler.
Compiling the Nexus 5 boot image with the 64-bit dex2oat
on host this CL reduces the memory used for compiling the
most hungry method, BatteryStats.dumpLocked(), by ~3.3MiB:
Before:
MEM: used: 47829200, allocated: 48769120, lost: 939920
Number of arenas allocated: 345,
Number of allocations: 815492, avg size: 58
...
UseListNode 13744640
...
After:
MEM: used: 44393040, allocated: 45361248, lost: 968208
Number of arenas allocated: 319,
Number of allocations: 815492, avg size: 54
...
UseListNode 10308480
...
Note that while we do not ship the 64-bit dex2oat to the
device, the JIT compilation for 64-bit processes is using
the 64-bit libart-compiler.
Bug: 28173563
Change-Id: I985eabd4816f845372d8aaa825a1489cf9569208
diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc
index 084360f..659c6f8 100644
--- a/compiler/optimizing/bounds_check_elimination.cc
+++ b/compiler/optimizing/bounds_check_elimination.cc
@@ -1206,9 +1206,9 @@
GetGraph()->GetArena()->Adapter(kArenaAllocBoundsCheckElimination));
ArenaVector<HBoundsCheck*> standby(
GetGraph()->GetArena()->Adapter(kArenaAllocBoundsCheckElimination));
- for (HUseIterator<HInstruction*> it2(array_length->GetUses()); !it2.Done(); it2.Advance()) {
+ for (const HUseListNode<HInstruction*>& use : array_length->GetUses()) {
// Another bounds check in same or dominated block?
- HInstruction* user = it2.Current()->GetUser();
+ HInstruction* user = use.GetUser();
HBasicBlock* other_block = user->GetBlock();
if (user->IsBoundsCheck() && block->Dominates(other_block)) {
HBoundsCheck* other_bounds_check = user->AsBoundsCheck();
@@ -1635,29 +1635,33 @@
Primitive::Type type = instruction->GetType();
HPhi* phi = nullptr;
// Scan all uses of an instruction and replace each later use with a phi node.
- for (HUseIterator<HInstruction*> it2(instruction->GetUses());
- !it2.Done();
- it2.Advance()) {
- HInstruction* user = it2.Current()->GetUser();
+ const HUseList<HInstruction*>& uses = instruction->GetUses();
+ for (auto it2 = uses.begin(), end2 = uses.end(); it2 != end2; /* ++it2 below */) {
+ HInstruction* user = it2->GetUser();
+ size_t index = it2->GetIndex();
+ // Increment `it2` now because `*it2` may disappear thanks to user->ReplaceInput().
+ ++it2;
if (user->GetBlock() != true_block) {
if (phi == nullptr) {
phi = NewPhi(new_preheader, instruction, type);
}
- user->ReplaceInput(phi, it2.Current()->GetIndex());
+ user->ReplaceInput(phi, index); // Removes the use node from the list.
}
}
// Scan all environment uses of an instruction and replace each later use with a phi node.
- for (HUseIterator<HEnvironment*> it2(instruction->GetEnvUses());
- !it2.Done();
- it2.Advance()) {
- HEnvironment* user = it2.Current()->GetUser();
+ const HUseList<HEnvironment*>& env_uses = instruction->GetEnvUses();
+ for (auto it2 = env_uses.begin(), end2 = env_uses.end(); it2 != end2; /* ++it2 below */) {
+ HEnvironment* user = it2->GetUser();
+ size_t index = it2->GetIndex();
+ // Increment `it2` now because `*it2` may disappear thanks to user->RemoveAsUserOfInput().
+ ++it2;
if (user->GetHolder()->GetBlock() != true_block) {
if (phi == nullptr) {
phi = NewPhi(new_preheader, instruction, type);
}
- user->RemoveAsUserOfInput(it2.Current()->GetIndex());
- user->SetRawEnvAt(it2.Current()->GetIndex(), phi);
- phi->AddEnvUseAt(user, it2.Current()->GetIndex());
+ user->RemoveAsUserOfInput(index);
+ user->SetRawEnvAt(index, phi);
+ phi->AddEnvUseAt(user, index);
}
}
}