Merge "Move PC-relative addressing bases to a better position."
diff --git a/compiler/optimizing/dex_cache_array_fixups_arm.cc b/compiler/optimizing/dex_cache_array_fixups_arm.cc
index 7f5f0e5..6582063 100644
--- a/compiler/optimizing/dex_cache_array_fixups_arm.cc
+++ b/compiler/optimizing/dex_cache_array_fixups_arm.cc
@@ -33,6 +33,16 @@
// Attribute memory use to code generator.
graph->GetArena()->Adapter(kArenaAllocCodeGenerator)) {}
+ void MoveBasesIfNeeded() {
+ for (const auto& entry : dex_cache_array_bases_) {
+ // Bring the base closer to the first use (previously, it was in the
+ // entry block) and relieve some pressure on the register allocator
+ // while avoiding recalculation of the base in a loop.
+ HArmDexCacheArraysBase* base = entry.second;
+ base->MoveBeforeFirstUserAndOutOfLoops();
+ }
+ }
+
private:
void VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) OVERRIDE {
// If this is an invoke with PC-relative access to the dex cache methods array,
@@ -40,7 +50,7 @@
if (invoke->HasPcRelativeDexCache()) {
// Initialize base for target method dex file if needed.
MethodReference target_method = invoke->GetTargetMethod();
- HArmDexCacheArraysBase* base = GetOrCreateDexCacheArrayBase(invoke, *target_method.dex_file);
+ HArmDexCacheArraysBase* base = GetOrCreateDexCacheArrayBase(*target_method.dex_file);
// Update the element offset in base.
DexCacheArraysLayout layout(kArmPointerSize, target_method.dex_file);
base->UpdateElementOffset(layout.MethodOffset(target_method.dex_method_index));
@@ -50,8 +60,7 @@
}
}
- HArmDexCacheArraysBase* GetOrCreateDexCacheArrayBase(HInstruction* user,
- const DexFile& dex_file) {
+ HArmDexCacheArraysBase* GetOrCreateDexCacheArrayBase(const DexFile& dex_file) {
// Ensure we only initialize the pointer once for each dex file.
auto lb = dex_cache_array_bases_.lower_bound(&dex_file);
if (lb != dex_cache_array_bases_.end() &&
@@ -59,11 +68,11 @@
return lb->second;
}
- HGraph* graph = GetGraph();
- HBasicBlock* entry = graph->GetEntryBlock();
- HArmDexCacheArraysBase* base = new (graph->GetArena()) HArmDexCacheArraysBase(dex_file);
- HInstruction* insert_pos = (user->GetBlock() == entry) ? user : entry->GetLastInstruction();
- entry->InsertInstructionBefore(base, insert_pos);
+ // Insert the base at the start of the entry block, move it to a better
+ // position later in MoveBaseIfNeeded().
+ HArmDexCacheArraysBase* base = new (GetGraph()->GetArena()) HArmDexCacheArraysBase(dex_file);
+ HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
+ entry_block->InsertInstructionBefore(base, entry_block->GetFirstInstruction());
dex_cache_array_bases_.PutBefore(lb, &dex_file, base);
return base;
}
@@ -76,6 +85,7 @@
void DexCacheArrayFixups::Run() {
DexCacheArrayFixupsVisitor visitor(graph_);
visitor.VisitInsertionOrder();
+ visitor.MoveBasesIfNeeded();
}
} // namespace arm
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index b5ac773..847d147 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -1177,6 +1177,59 @@
}
}
+void HInstruction::MoveBeforeFirstUserAndOutOfLoops() {
+ DCHECK(!CanThrow());
+ DCHECK(!HasSideEffects());
+ DCHECK(!HasEnvironmentUses());
+ DCHECK(HasNonEnvironmentUses());
+ DCHECK(!IsPhi()); // Makes no sense for Phi.
+ DCHECK_EQ(InputCount(), 0u);
+
+ // Find the target block.
+ HUseIterator<HInstruction*> uses_it(GetUses());
+ HBasicBlock* target_block = uses_it.Current()->GetUser()->GetBlock();
+ uses_it.Advance();
+ while (!uses_it.Done() && uses_it.Current()->GetUser()->GetBlock() == target_block) {
+ uses_it.Advance();
+ }
+ if (!uses_it.Done()) {
+ // This instruction has uses in two or more blocks. Find the common dominator.
+ CommonDominator finder(target_block);
+ for (; !uses_it.Done(); uses_it.Advance()) {
+ finder.Update(uses_it.Current()->GetUser()->GetBlock());
+ }
+ target_block = finder.Get();
+ DCHECK(target_block != nullptr);
+ }
+ // Move to the first dominator not in a loop.
+ while (target_block->IsInLoop()) {
+ target_block = target_block->GetDominator();
+ DCHECK(target_block != nullptr);
+ }
+
+ // Find insertion position.
+ HInstruction* insert_pos = nullptr;
+ for (HUseIterator<HInstruction*> uses_it2(GetUses()); !uses_it2.Done(); uses_it2.Advance()) {
+ if (uses_it2.Current()->GetUser()->GetBlock() == target_block &&
+ (insert_pos == nullptr || uses_it2.Current()->GetUser()->StrictlyDominates(insert_pos))) {
+ insert_pos = uses_it2.Current()->GetUser();
+ }
+ }
+ if (insert_pos == nullptr) {
+ // No user in `target_block`, insert before the control flow instruction.
+ insert_pos = target_block->GetLastInstruction();
+ DCHECK(insert_pos->IsControlFlow());
+ // Avoid splitting HCondition from HIf to prevent unnecessary materialization.
+ if (insert_pos->IsIf()) {
+ HInstruction* if_input = insert_pos->AsIf()->InputAt(0);
+ if (if_input == insert_pos->GetPrevious()) {
+ insert_pos = if_input;
+ }
+ }
+ }
+ MoveBefore(insert_pos);
+}
+
HBasicBlock* HBasicBlock::SplitBefore(HInstruction* cursor) {
DCHECK(!graph_->IsInSsaForm()) << "Support for SSA form not implemented.";
DCHECK_EQ(cursor->GetBlock(), this);
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 9c33a0f..441aa04 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -1957,6 +1957,14 @@
// Move `this` instruction before `cursor`.
void MoveBefore(HInstruction* cursor);
+ // Move `this` before its first user and out of any loops. If there is no
+ // out-of-loop user that dominates all other users, move the instruction
+ // to the end of the out-of-loop common dominator of the user's blocks.
+ //
+ // This can be used only on non-throwing instructions with no side effects that
+ // have at least one use but no environment uses.
+ void MoveBeforeFirstUserAndOutOfLoops();
+
#define INSTRUCTION_TYPE_CHECK(type, super) \
bool Is##type() const { return (As##type() != nullptr); } \
virtual const H##type* As##type() const { return nullptr; } \
diff --git a/compiler/optimizing/pc_relative_fixups_x86.cc b/compiler/optimizing/pc_relative_fixups_x86.cc
index 808a1dc..b383f1e 100644
--- a/compiler/optimizing/pc_relative_fixups_x86.cc
+++ b/compiler/optimizing/pc_relative_fixups_x86.cc
@@ -26,6 +26,15 @@
public:
explicit PCRelativeHandlerVisitor(HGraph* graph) : HGraphVisitor(graph), base_(nullptr) {}
+ void MoveBaseIfNeeded() {
+ if (base_ != nullptr) {
+ // Bring the base closer to the first use (previously, it was in the
+ // entry block) and relieve some pressure on the register allocator
+ // while avoiding recalculation of the base in a loop.
+ base_->MoveBeforeFirstUserAndOutOfLoops();
+ }
+ }
+
private:
void VisitAdd(HAdd* add) OVERRIDE {
BinaryFP(add);
@@ -72,7 +81,7 @@
void VisitPackedSwitch(HPackedSwitch* switch_insn) OVERRIDE {
// We need to replace the HPackedSwitch with a HX86PackedSwitch in order to
// address the constant area.
- InitializePCRelativeBasePointer(switch_insn);
+ InitializePCRelativeBasePointer();
HGraph* graph = GetGraph();
HBasicBlock* block = switch_insn->GetBlock();
HX86PackedSwitch* x86_switch = new (graph->GetArena()) HX86PackedSwitch(
@@ -84,22 +93,22 @@
block->ReplaceAndRemoveInstructionWith(switch_insn, x86_switch);
}
- void InitializePCRelativeBasePointer(HInstruction* user) {
+ void InitializePCRelativeBasePointer() {
// Ensure we only initialize the pointer once.
if (base_ != nullptr) {
return;
}
- HGraph* graph = GetGraph();
- HBasicBlock* entry = graph->GetEntryBlock();
- base_ = new (graph->GetArena()) HX86ComputeBaseMethodAddress();
- HInstruction* insert_pos = (user->GetBlock() == entry) ? user : entry->GetLastInstruction();
- entry->InsertInstructionBefore(base_, insert_pos);
+ // Insert the base at the start of the entry block, move it to a better
+ // position later in MoveBaseIfNeeded().
+ base_ = new (GetGraph()->GetArena()) HX86ComputeBaseMethodAddress();
+ HBasicBlock* entry_block = GetGraph()->GetEntryBlock();
+ entry_block->InsertInstructionBefore(base_, entry_block->GetFirstInstruction());
DCHECK(base_ != nullptr);
}
void ReplaceInput(HInstruction* insn, HConstant* value, int input_index, bool materialize) {
- InitializePCRelativeBasePointer(insn);
+ InitializePCRelativeBasePointer();
HX86LoadFromConstantTable* load_constant =
new (GetGraph()->GetArena()) HX86LoadFromConstantTable(base_, value, materialize);
insn->GetBlock()->InsertInstructionBefore(load_constant, insn);
@@ -111,7 +120,7 @@
// addressing, we need the PC-relative address base.
HInvokeStaticOrDirect* invoke_static_or_direct = invoke->AsInvokeStaticOrDirect();
if (invoke_static_or_direct != nullptr && invoke_static_or_direct->HasPcRelativeDexCache()) {
- InitializePCRelativeBasePointer(invoke);
+ InitializePCRelativeBasePointer();
// Add the extra parameter base_.
DCHECK(!invoke_static_or_direct->HasCurrentMethodInput());
invoke_static_or_direct->AddSpecialInput(base_);
@@ -133,6 +142,7 @@
void PcRelativeFixups::Run() {
PCRelativeHandlerVisitor visitor(graph_);
visitor.VisitInsertionOrder();
+ visitor.MoveBaseIfNeeded();
}
} // namespace x86
