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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "nodes.h"
#include <cfloat>
#include "art_method-inl.h"
#include "base/bit_utils.h"
#include "base/bit_vector-inl.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "class_linker-inl.h"
#include "class_root.h"
#include "code_generator.h"
#include "common_dominator.h"
#include "intrinsics.h"
#include "mirror/class-inl.h"
#include "scoped_thread_state_change-inl.h"
#include "ssa_builder.h"
namespace art {
// Enable floating-point static evaluation during constant folding
// only if all floating-point operations and constants evaluate in the
// range and precision of the type used (i.e., 32-bit float, 64-bit
// double).
static constexpr bool kEnableFloatingPointStaticEvaluation = (FLT_EVAL_METHOD == 0);
void HGraph::InitializeInexactObjectRTI(VariableSizedHandleScope* handles) {
ScopedObjectAccess soa(Thread::Current());
// Create the inexact Object reference type and store it in the HGraph.
inexact_object_rti_ = ReferenceTypeInfo::Create(
handles->NewHandle(GetClassRoot<mirror::Object>()),
/* is_exact= */ false);
}
void HGraph::AddBlock(HBasicBlock* block) {
block->SetBlockId(blocks_.size());
blocks_.push_back(block);
}
void HGraph::FindBackEdges(ArenaBitVector* visited) {
// "visited" must be empty on entry, it's an output argument for all visited (i.e. live) blocks.
DCHECK_EQ(visited->GetHighestBitSet(), -1);
// Allocate memory from local ScopedArenaAllocator.
ScopedArenaAllocator allocator(GetArenaStack());
// Nodes that we're currently visiting, indexed by block id.
ArenaBitVector visiting(
&allocator, blocks_.size(), /* expandable= */ false, kArenaAllocGraphBuilder);
visiting.ClearAllBits();
// Number of successors visited from a given node, indexed by block id.
ScopedArenaVector<size_t> successors_visited(blocks_.size(),
0u,
allocator.Adapter(kArenaAllocGraphBuilder));
// Stack of nodes that we're currently visiting (same as marked in "visiting" above).
ScopedArenaVector<HBasicBlock*> worklist(allocator.Adapter(kArenaAllocGraphBuilder));
constexpr size_t kDefaultWorklistSize = 8;
worklist.reserve(kDefaultWorklistSize);
visited->SetBit(entry_block_->GetBlockId());
visiting.SetBit(entry_block_->GetBlockId());
worklist.push_back(entry_block_);
while (!worklist.empty()) {
HBasicBlock* current = worklist.back();
uint32_t current_id = current->GetBlockId();
if (successors_visited[current_id] == current->GetSuccessors().size()) {
visiting.ClearBit(current_id);
worklist.pop_back();
} else {
HBasicBlock* successor = current->GetSuccessors()[successors_visited[current_id]++];
uint32_t successor_id = successor->GetBlockId();
if (visiting.IsBitSet(successor_id)) {
DCHECK(ContainsElement(worklist, successor));
successor->AddBackEdge(current);
} else if (!visited->IsBitSet(successor_id)) {
visited->SetBit(successor_id);
visiting.SetBit(successor_id);
worklist.push_back(successor);
}
}
}
}
// Remove the environment use records of the instruction for users.
void RemoveEnvironmentUses(HInstruction* instruction) {
for (HEnvironment* environment = instruction->GetEnvironment();
environment != nullptr;
environment = environment->GetParent()) {
for (size_t i = 0, e = environment->Size(); i < e; ++i) {
if (environment->GetInstructionAt(i) != nullptr) {
environment->RemoveAsUserOfInput(i);
}
}
}
}
// Return whether the instruction has an environment and it's used by others.
bool HasEnvironmentUsedByOthers(HInstruction* instruction) {
for (HEnvironment* environment = instruction->GetEnvironment();
environment != nullptr;
environment = environment->GetParent()) {
for (size_t i = 0, e = environment->Size(); i < e; ++i) {
HInstruction* user = environment->GetInstructionAt(i);
if (user != nullptr) {
return true;
}
}
}
return false;
}
// Reset environment records of the instruction itself.
void ResetEnvironmentInputRecords(HInstruction* instruction) {
for (HEnvironment* environment = instruction->GetEnvironment();
environment != nullptr;
environment = environment->GetParent()) {
for (size_t i = 0, e = environment->Size(); i < e; ++i) {
DCHECK(environment->GetHolder() == instruction);
if (environment->GetInstructionAt(i) != nullptr) {
environment->SetRawEnvAt(i, nullptr);
}
}
}
}
static void RemoveAsUser(HInstruction* instruction) {
instruction->RemoveAsUserOfAllInputs();
RemoveEnvironmentUses(instruction);
}
void HGraph::RemoveInstructionsAsUsersFromDeadBlocks(const ArenaBitVector& visited) const {
for (size_t i = 0; i < blocks_.size(); ++i) {
if (!visited.IsBitSet(i)) {
HBasicBlock* block = blocks_[i];
if (block == nullptr) continue;
DCHECK(block->GetPhis().IsEmpty()) << "Phis are not inserted at this stage";
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
RemoveAsUser(it.Current());
}
}
}
}
void HGraph::RemoveDeadBlocks(const ArenaBitVector& visited) {
for (size_t i = 0; i < blocks_.size(); ++i) {
if (!visited.IsBitSet(i)) {
HBasicBlock* block = blocks_[i];
if (block == nullptr) continue;
// We only need to update the successor, which might be live.
for (HBasicBlock* successor : block->GetSuccessors()) {
successor->RemovePredecessor(block);
}
// Remove the block from the list of blocks, so that further analyses
// never see it.
blocks_[i] = nullptr;
if (block->IsExitBlock()) {
SetExitBlock(nullptr);
}
// Mark the block as removed. This is used by the HGraphBuilder to discard
// the block as a branch target.
block->SetGraph(nullptr);
}
}
}
GraphAnalysisResult HGraph::BuildDominatorTree() {
// Allocate memory from local ScopedArenaAllocator.
ScopedArenaAllocator allocator(GetArenaStack());
ArenaBitVector visited(&allocator, blocks_.size(), false, kArenaAllocGraphBuilder);
visited.ClearAllBits();
// (1) Find the back edges in the graph doing a DFS traversal.
FindBackEdges(&visited);
// (2) Remove instructions and phis from blocks not visited during
// the initial DFS as users from other instructions, so that
// users can be safely removed before uses later.
RemoveInstructionsAsUsersFromDeadBlocks(visited);
// (3) Remove blocks not visited during the initial DFS.
// Step (5) requires dead blocks to be removed from the
// predecessors list of live blocks.
RemoveDeadBlocks(visited);
// (4) Simplify the CFG now, so that we don't need to recompute
// dominators and the reverse post order.
SimplifyCFG();
// (5) Compute the dominance information and the reverse post order.
ComputeDominanceInformation();
// (6) Analyze loops discovered through back edge analysis, and
// set the loop information on each block.
GraphAnalysisResult result = AnalyzeLoops();
if (result != kAnalysisSuccess) {
return result;
}
// (7) Precompute per-block try membership before entering the SSA builder,
// which needs the information to build catch block phis from values of
// locals at throwing instructions inside try blocks.
ComputeTryBlockInformation();
return kAnalysisSuccess;
}
void HGraph::ClearDominanceInformation() {
for (HBasicBlock* block : GetReversePostOrder()) {
block->ClearDominanceInformation();
}
reverse_post_order_.clear();
}
void HGraph::ClearLoopInformation() {
SetHasIrreducibleLoops(false);
for (HBasicBlock* block : GetReversePostOrder()) {
block->SetLoopInformation(nullptr);
}
}
void HBasicBlock::ClearDominanceInformation() {
dominated_blocks_.clear();
dominator_ = nullptr;
}
HInstruction* HBasicBlock::GetFirstInstructionDisregardMoves() const {
HInstruction* instruction = GetFirstInstruction();
while (instruction->IsParallelMove()) {
instruction = instruction->GetNext();
}
return instruction;
}
static bool UpdateDominatorOfSuccessor(HBasicBlock* block, HBasicBlock* successor) {
DCHECK(ContainsElement(block->GetSuccessors(), successor));
HBasicBlock* old_dominator = successor->GetDominator();
HBasicBlock* new_dominator =
(old_dominator == nullptr) ? block
: CommonDominator::ForPair(old_dominator, block);
if (old_dominator == new_dominator) {
return false;
} else {
successor->SetDominator(new_dominator);
return true;
}
}
void HGraph::ComputeDominanceInformation() {
DCHECK(reverse_post_order_.empty());
reverse_post_order_.reserve(blocks_.size());
reverse_post_order_.push_back(entry_block_);
// Allocate memory from local ScopedArenaAllocator.
ScopedArenaAllocator allocator(GetArenaStack());
// Number of visits of a given node, indexed by block id.
ScopedArenaVector<size_t> visits(blocks_.size(), 0u, allocator.Adapter(kArenaAllocGraphBuilder));
// Number of successors visited from a given node, indexed by block id.
ScopedArenaVector<size_t> successors_visited(blocks_.size(),
0u,
allocator.Adapter(kArenaAllocGraphBuilder));
// Nodes for which we need to visit successors.
ScopedArenaVector<HBasicBlock*> worklist(allocator.Adapter(kArenaAllocGraphBuilder));
constexpr size_t kDefaultWorklistSize = 8;
worklist.reserve(kDefaultWorklistSize);
worklist.push_back(entry_block_);
while (!worklist.empty()) {
HBasicBlock* current = worklist.back();
uint32_t current_id = current->GetBlockId();
if (successors_visited[current_id] == current->GetSuccessors().size()) {
worklist.pop_back();
} else {
HBasicBlock* successor = current->GetSuccessors()[successors_visited[current_id]++];
UpdateDominatorOfSuccessor(current, successor);
// Once all the forward edges have been visited, we know the immediate
// dominator of the block. We can then start visiting its successors.
if (++visits[successor->GetBlockId()] ==
successor->GetPredecessors().size() - successor->NumberOfBackEdges()) {
reverse_post_order_.push_back(successor);
worklist.push_back(successor);
}
}
}
// Check if the graph has back edges not dominated by their respective headers.
// If so, we need to update the dominators of those headers and recursively of
// their successors. We do that with a fix-point iteration over all blocks.
// The algorithm is guaranteed to terminate because it loops only if the sum
// of all dominator chains has decreased in the current iteration.
bool must_run_fix_point = false;
for (HBasicBlock* block : blocks_) {
if (block != nullptr &&
block->IsLoopHeader() &&
block->GetLoopInformation()->HasBackEdgeNotDominatedByHeader()) {
must_run_fix_point = true;
break;
}
}
if (must_run_fix_point) {
bool update_occurred = true;
while (update_occurred) {
update_occurred = false;
for (HBasicBlock* block : GetReversePostOrder()) {
for (HBasicBlock* successor : block->GetSuccessors()) {
update_occurred |= UpdateDominatorOfSuccessor(block, successor);
}
}
}
}
// Make sure that there are no remaining blocks whose dominator information
// needs to be updated.
if (kIsDebugBuild) {
for (HBasicBlock* block : GetReversePostOrder()) {
for (HBasicBlock* successor : block->GetSuccessors()) {
DCHECK(!UpdateDominatorOfSuccessor(block, successor));
}
}
}
// Populate `dominated_blocks_` information after computing all dominators.
// The potential presence of irreducible loops requires to do it after.
for (HBasicBlock* block : GetReversePostOrder()) {
if (!block->IsEntryBlock()) {
block->GetDominator()->AddDominatedBlock(block);
}
}
}
HBasicBlock* HGraph::SplitEdge(HBasicBlock* block, HBasicBlock* successor) {
HBasicBlock* new_block = new (allocator_) HBasicBlock(this, successor->GetDexPc());
AddBlock(new_block);
// Use `InsertBetween` to ensure the predecessor index and successor index of
// `block` and `successor` are preserved.
new_block->InsertBetween(block, successor);
return new_block;
}
void HGraph::SplitCriticalEdge(HBasicBlock* block, HBasicBlock* successor) {
// Insert a new node between `block` and `successor` to split the
// critical edge.
HBasicBlock* new_block = SplitEdge(block, successor);
new_block->AddInstruction(new (allocator_) HGoto(successor->GetDexPc()));
if (successor->IsLoopHeader()) {
// If we split at a back edge boundary, make the new block the back edge.
HLoopInformation* info = successor->GetLoopInformation();
if (info->IsBackEdge(*block)) {
info->RemoveBackEdge(block);
info->AddBackEdge(new_block);
}
}
}
// Reorder phi inputs to match reordering of the block's predecessors.
static void FixPhisAfterPredecessorsReodering(HBasicBlock* block, size_t first, size_t second) {
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
HPhi* phi = it.Current()->AsPhi();
HInstruction* first_instr = phi->InputAt(first);
HInstruction* second_instr = phi->InputAt(second);
phi->ReplaceInput(first_instr, second);
phi->ReplaceInput(second_instr, first);
}
}
// Make sure that the first predecessor of a loop header is the incoming block.
void HGraph::OrderLoopHeaderPredecessors(HBasicBlock* header) {
DCHECK(header->IsLoopHeader());
HLoopInformation* info = header->GetLoopInformation();
if (info->IsBackEdge(*header->GetPredecessors()[0])) {
HBasicBlock* to_swap = header->GetPredecessors()[0];
for (size_t pred = 1, e = header->GetPredecessors().size(); pred < e; ++pred) {
HBasicBlock* predecessor = header->GetPredecessors()[pred];
if (!info->IsBackEdge(*predecessor)) {
header->predecessors_[pred] = to_swap;
header->predecessors_[0] = predecessor;
FixPhisAfterPredecessorsReodering(header, 0, pred);
break;
}
}
}
}
// Transform control flow of the loop to a single preheader format (don't touch the data flow).
// New_preheader can be already among the header predecessors - this situation will be correctly
// processed.
static void FixControlForNewSinglePreheader(HBasicBlock* header, HBasicBlock* new_preheader) {
HLoopInformation* loop_info = header->GetLoopInformation();
for (size_t pred = 0; pred < header->GetPredecessors().size(); ++pred) {
HBasicBlock* predecessor = header->GetPredecessors()[pred];
if (!loop_info->IsBackEdge(*predecessor) && predecessor != new_preheader) {
predecessor->ReplaceSuccessor(header, new_preheader);
pred--;
}
}
}
// == Before == == After ==
// _________ _________ _________ _________
// | B0 | | B1 | (old preheaders) | B0 | | B1 |
// |=========| |=========| |=========| |=========|
// | i0 = .. | | i1 = .. | | i0 = .. | | i1 = .. |
// |_________| |_________| |_________| |_________|
// \ / \ /
// \ / ___v____________v___
// \ / (new preheader) | B20 <- B0, B1 |
// | | |====================|
// | | | i20 = phi(i0, i1) |
// | | |____________________|
// | | |
// /\ | | /\ /\ | /\
// / v_______v_________v_______v \ / v___________v_____________v \
// | | B10 <- B0, B1, B2, B3 | | | | B10 <- B20, B2, B3 | |
// | |===========================| | (header) | |===========================| |
// | | i10 = phi(i0, i1, i2, i3) | | | | i10 = phi(i20, i2, i3) | |
// | |___________________________| | | |___________________________| |
// | / \ | | / \ |
// | ... ... | | ... ... |
// | _________ _________ | | _________ _________ |
// | | B2 | | B3 | | | | B2 | | B3 | |
// | |=========| |=========| | (back edges) | |=========| |=========| |
// | | i2 = .. | | i3 = .. | | | | i2 = .. | | i3 = .. | |
// | |_________| |_________| | | |_________| |_________| |
// \ / \ / \ / \ /
// \___/ \___/ \___/ \___/
//
void HGraph::TransformLoopToSinglePreheaderFormat(HBasicBlock* header) {
HLoopInformation* loop_info = header->GetLoopInformation();
HBasicBlock* preheader = new (allocator_) HBasicBlock(this, header->GetDexPc());
AddBlock(preheader);
preheader->AddInstruction(new (allocator_) HGoto(header->GetDexPc()));
// If the old header has no Phis then we only need to fix the control flow.
if (header->GetPhis().IsEmpty()) {
FixControlForNewSinglePreheader(header, preheader);
preheader->AddSuccessor(header);
return;
}
// Find the first non-back edge block in the header's predecessors list.
size_t first_nonbackedge_pred_pos = 0;
bool found = false;
for (size_t pred = 0; pred < header->GetPredecessors().size(); ++pred) {
HBasicBlock* predecessor = header->GetPredecessors()[pred];
if (!loop_info->IsBackEdge(*predecessor)) {
first_nonbackedge_pred_pos = pred;
found = true;
break;
}
}
DCHECK(found);
// Fix the data-flow.
for (HInstructionIterator it(header->GetPhis()); !it.Done(); it.Advance()) {
HPhi* header_phi = it.Current()->AsPhi();
HPhi* preheader_phi = new (GetAllocator()) HPhi(GetAllocator(),
header_phi->GetRegNumber(),
0,
header_phi->GetType());
if (header_phi->GetType() == DataType::Type::kReference) {
preheader_phi->SetReferenceTypeInfo(header_phi->GetReferenceTypeInfo());
}
preheader->AddPhi(preheader_phi);
HInstruction* orig_input = header_phi->InputAt(first_nonbackedge_pred_pos);
header_phi->ReplaceInput(preheader_phi, first_nonbackedge_pred_pos);
preheader_phi->AddInput(orig_input);
for (size_t input_pos = first_nonbackedge_pred_pos + 1;
input_pos < header_phi->InputCount();
input_pos++) {
HInstruction* input = header_phi->InputAt(input_pos);
HBasicBlock* pred_block = header->GetPredecessors()[input_pos];
if (loop_info->Contains(*pred_block)) {
DCHECK(loop_info->IsBackEdge(*pred_block));
} else {
preheader_phi->AddInput(input);
header_phi->RemoveInputAt(input_pos);
input_pos--;
}
}
}
// Fix the control-flow.
HBasicBlock* first_pred = header->GetPredecessors()[first_nonbackedge_pred_pos];
preheader->InsertBetween(first_pred, header);
FixControlForNewSinglePreheader(header, preheader);
}
void HGraph::SimplifyLoop(HBasicBlock* header) {
HLoopInformation* info = header->GetLoopInformation();
// Make sure the loop has only one pre header. This simplifies SSA building by having
// to just look at the pre header to know which locals are initialized at entry of the
// loop. Also, don't allow the entry block to be a pre header: this simplifies inlining
// this graph.
size_t number_of_incomings = header->GetPredecessors().size() - info->NumberOfBackEdges();
if (number_of_incomings != 1 || (GetEntryBlock()->GetSingleSuccessor() == header)) {
TransformLoopToSinglePreheaderFormat(header);
}
OrderLoopHeaderPredecessors(header);
HInstruction* first_instruction = header->GetFirstInstruction();
if (first_instruction != nullptr && first_instruction->IsSuspendCheck()) {
// Called from DeadBlockElimination. Update SuspendCheck pointer.
info->SetSuspendCheck(first_instruction->AsSuspendCheck());
}
}
void HGraph::ComputeTryBlockInformation() {
// Iterate in reverse post order to propagate try membership information from
// predecessors to their successors.
for (HBasicBlock* block : GetReversePostOrder()) {
if (block->IsEntryBlock() || block->IsCatchBlock()) {
// Catch blocks after simplification have only exceptional predecessors
// and hence are never in tries.
continue;
}
// Infer try membership from the first predecessor. Having simplified loops,
// the first predecessor can never be a back edge and therefore it must have
// been visited already and had its try membership set.
HBasicBlock* first_predecessor = block->GetPredecessors()[0];
DCHECK(!block->IsLoopHeader() || !block->GetLoopInformation()->IsBackEdge(*first_predecessor));
const HTryBoundary* try_entry = first_predecessor->ComputeTryEntryOfSuccessors();
if (try_entry != nullptr &&
(block->GetTryCatchInformation() == nullptr ||
try_entry != &block->GetTryCatchInformation()->GetTryEntry())) {
// We are either setting try block membership for the first time or it
// has changed.
block->SetTryCatchInformation(new (allocator_) TryCatchInformation(*try_entry));
}
}
}
void HGraph::SimplifyCFG() {
// Simplify the CFG for future analysis, and code generation:
// (1): Split critical edges.
// (2): Simplify loops by having only one preheader.
// NOTE: We're appending new blocks inside the loop, so we need to use index because iterators
// can be invalidated. We remember the initial size to avoid iterating over the new blocks.
for (size_t block_id = 0u, end = blocks_.size(); block_id != end; ++block_id) {
HBasicBlock* block = blocks_[block_id];
if (block == nullptr) continue;
if (block->GetSuccessors().size() > 1) {
// Only split normal-flow edges. We cannot split exceptional edges as they
// are synthesized (approximate real control flow), and we do not need to
// anyway. Moves that would be inserted there are performed by the runtime.
ArrayRef<HBasicBlock* const> normal_successors = block->GetNormalSuccessors();
for (size_t j = 0, e = normal_successors.size(); j < e; ++j) {
HBasicBlock* successor = normal_successors[j];
DCHECK(!successor->IsCatchBlock());
if (successor == exit_block_) {
// (Throw/Return/ReturnVoid)->TryBoundary->Exit. Special case which we
// do not want to split because Goto->Exit is not allowed.
DCHECK(block->IsSingleTryBoundary());
} else if (successor->GetPredecessors().size() > 1) {
SplitCriticalEdge(block, successor);
// SplitCriticalEdge could have invalidated the `normal_successors`
// ArrayRef. We must re-acquire it.
normal_successors = block->GetNormalSuccessors();
DCHECK_EQ(normal_successors[j]->GetSingleSuccessor(), successor);
DCHECK_EQ(e, normal_successors.size());
}
}
}
if (block->IsLoopHeader()) {
SimplifyLoop(block);
} else if (!block->IsEntryBlock() &&
block->GetFirstInstruction() != nullptr &&
block->GetFirstInstruction()->IsSuspendCheck()) {
// We are being called by the dead code elimiation pass, and what used to be
// a loop got dismantled. Just remove the suspend check.
block->RemoveInstruction(block->GetFirstInstruction());
}
}
}
GraphAnalysisResult HGraph::AnalyzeLoops() const {
// We iterate post order to ensure we visit inner loops before outer loops.
// `PopulateRecursive` needs this guarantee to know whether a natural loop
// contains an irreducible loop.
for (HBasicBlock* block : GetPostOrder()) {
if (block->IsLoopHeader()) {
if (block->IsCatchBlock()) {
// TODO: Dealing with exceptional back edges could be tricky because
// they only approximate the real control flow. Bail out for now.
VLOG(compiler) << "Not compiled: Exceptional back edges";
return kAnalysisFailThrowCatchLoop;
}
block->GetLoopInformation()->Populate();
}
}
return kAnalysisSuccess;
}
void HLoopInformation::Dump(std::ostream& os) {
os << "header: " << header_->GetBlockId() << std::endl;
os << "pre header: " << GetPreHeader()->GetBlockId() << std::endl;
for (HBasicBlock* block : back_edges_) {
os << "back edge: " << block->GetBlockId() << std::endl;
}
for (HBasicBlock* block : header_->GetPredecessors()) {
os << "predecessor: " << block->GetBlockId() << std::endl;
}
for (uint32_t idx : blocks_.Indexes()) {
os << " in loop: " << idx << std::endl;
}
}
void HGraph::InsertConstant(HConstant* constant) {
// New constants are inserted before the SuspendCheck at the bottom of the
// entry block. Note that this method can be called from the graph builder and
// the entry block therefore may not end with SuspendCheck->Goto yet.
HInstruction* insert_before = nullptr;
HInstruction* gota = entry_block_->GetLastInstruction();
if (gota != nullptr && gota->IsGoto()) {
HInstruction* suspend_check = gota->GetPrevious();
if (suspend_check != nullptr && suspend_check->IsSuspendCheck()) {
insert_before = suspend_check;
} else {
insert_before = gota;
}
}
if (insert_before == nullptr) {
entry_block_->AddInstruction(constant);
} else {
entry_block_->InsertInstructionBefore(constant, insert_before);
}
}
HNullConstant* HGraph::GetNullConstant(uint32_t dex_pc) {
// For simplicity, don't bother reviving the cached null constant if it is
// not null and not in a block. Otherwise, we need to clear the instruction
// id and/or any invariants the graph is assuming when adding new instructions.
if ((cached_null_constant_ == nullptr) || (cached_null_constant_->GetBlock() == nullptr)) {
cached_null_constant_ = new (allocator_) HNullConstant(dex_pc);
cached_null_constant_->SetReferenceTypeInfo(inexact_object_rti_);
InsertConstant(cached_null_constant_);
}
if (kIsDebugBuild) {
ScopedObjectAccess soa(Thread::Current());
DCHECK(cached_null_constant_->GetReferenceTypeInfo().IsValid());
}
return cached_null_constant_;
}
HCurrentMethod* HGraph::GetCurrentMethod() {
// For simplicity, don't bother reviving the cached current method if it is
// not null and not in a block. Otherwise, we need to clear the instruction
// id and/or any invariants the graph is assuming when adding new instructions.
if ((cached_current_method_ == nullptr) || (cached_current_method_->GetBlock() == nullptr)) {
cached_current_method_ = new (allocator_) HCurrentMethod(
Is64BitInstructionSet(instruction_set_) ? DataType::Type::kInt64 : DataType::Type::kInt32,
entry_block_->GetDexPc());
if (entry_block_->GetFirstInstruction() == nullptr) {
entry_block_->AddInstruction(cached_current_method_);
} else {
entry_block_->InsertInstructionBefore(
cached_current_method_, entry_block_->GetFirstInstruction());
}
}
return cached_current_method_;
}
const char* HGraph::GetMethodName() const {
const DexFile::MethodId& method_id = dex_file_.GetMethodId(method_idx_);
return dex_file_.GetMethodName(method_id);
}
std::string HGraph::PrettyMethod(bool with_signature) const {
return dex_file_.PrettyMethod(method_idx_, with_signature);
}
HConstant* HGraph::GetConstant(DataType::Type type, int64_t value, uint32_t dex_pc) {
switch (type) {
case DataType::Type::kBool:
DCHECK(IsUint<1>(value));
FALLTHROUGH_INTENDED;
case DataType::Type::kUint8:
case DataType::Type::kInt8:
case DataType::Type::kUint16:
case DataType::Type::kInt16:
case DataType::Type::kInt32:
DCHECK(IsInt(DataType::Size(type) * kBitsPerByte, value));
return GetIntConstant(static_cast<int32_t>(value), dex_pc);
case DataType::Type::kInt64:
return GetLongConstant(value, dex_pc);
default:
LOG(FATAL) << "Unsupported constant type";
UNREACHABLE();
}
}
void HGraph::CacheFloatConstant(HFloatConstant* constant) {
int32_t value = bit_cast<int32_t, float>(constant->GetValue());
DCHECK(cached_float_constants_.find(value) == cached_float_constants_.end());
cached_float_constants_.Overwrite(value, constant);
}
void HGraph::CacheDoubleConstant(HDoubleConstant* constant) {
int64_t value = bit_cast<int64_t, double>(constant->GetValue());
DCHECK(cached_double_constants_.find(value) == cached_double_constants_.end());
cached_double_constants_.Overwrite(value, constant);
}
void HLoopInformation::Add(HBasicBlock* block) {
blocks_.SetBit(block->GetBlockId());
}
void HLoopInformation::Remove(HBasicBlock* block) {
blocks_.ClearBit(block->GetBlockId());
}
void HLoopInformation::PopulateRecursive(HBasicBlock* block) {
if (blocks_.IsBitSet(block->GetBlockId())) {
return;
}
blocks_.SetBit(block->GetBlockId());
block->SetInLoop(this);
if (block->IsLoopHeader()) {
// We're visiting loops in post-order, so inner loops must have been
// populated already.
DCHECK(block->GetLoopInformation()->IsPopulated());
if (block->GetLoopInformation()->IsIrreducible()) {
contains_irreducible_loop_ = true;
}
}
for (HBasicBlock* predecessor : block->GetPredecessors()) {
PopulateRecursive(predecessor);
}
}
void HLoopInformation::PopulateIrreducibleRecursive(HBasicBlock* block, ArenaBitVector* finalized) {
size_t block_id = block->GetBlockId();
// If `block` is in `finalized`, we know its membership in the loop has been
// decided and it does not need to be revisited.
if (finalized->IsBitSet(block_id)) {
return;
}
bool is_finalized = false;
if (block->IsLoopHeader()) {
// If we hit a loop header in an irreducible loop, we first check if the
// pre header of that loop belongs to the currently analyzed loop. If it does,
// then we visit the back edges.
// Note that we cannot use GetPreHeader, as the loop may have not been populated
// yet.
HBasicBlock* pre_header = block->GetPredecessors()[0];
PopulateIrreducibleRecursive(pre_header, finalized);
if (blocks_.IsBitSet(pre_header->GetBlockId())) {
block->SetInLoop(this);
blocks_.SetBit(block_id);
finalized->SetBit(block_id);
is_finalized = true;
HLoopInformation* info = block->GetLoopInformation();
for (HBasicBlock* back_edge : info->GetBackEdges()) {
PopulateIrreducibleRecursive(back_edge, finalized);
}
}
} else {
// Visit all predecessors. If one predecessor is part of the loop, this
// block is also part of this loop.
for (HBasicBlock* predecessor : block->GetPredecessors()) {
PopulateIrreducibleRecursive(predecessor, finalized);
if (!is_finalized && blocks_.IsBitSet(predecessor->GetBlockId())) {
block->SetInLoop(this);
blocks_.SetBit(block_id);
finalized->SetBit(block_id);
is_finalized = true;
}
}
}
// All predecessors have been recursively visited. Mark finalized if not marked yet.
if (!is_finalized) {
finalized->SetBit(block_id);
}
}
void HLoopInformation::Populate() {
DCHECK_EQ(blocks_.NumSetBits(), 0u) << "Loop information has already been populated";
// Populate this loop: starting with the back edge, recursively add predecessors
// that are not already part of that loop. Set the header as part of the loop
// to end the recursion.
// This is a recursive implementation of the algorithm described in
// "Advanced Compiler Design & Implementation" (Muchnick) p192.
HGraph* graph = header_->GetGraph();
blocks_.SetBit(header_->GetBlockId());
header_->SetInLoop(this);
bool is_irreducible_loop = HasBackEdgeNotDominatedByHeader();
if (is_irreducible_loop) {
// Allocate memory from local ScopedArenaAllocator.
ScopedArenaAllocator allocator(graph->GetArenaStack());
ArenaBitVector visited(&allocator,
graph->GetBlocks().size(),
/* expandable= */ false,
kArenaAllocGraphBuilder);
visited.ClearAllBits();
// Stop marking blocks at the loop header.
visited.SetBit(header_->GetBlockId());
for (HBasicBlock* back_edge : GetBackEdges()) {
PopulateIrreducibleRecursive(back_edge, &visited);
}
} else {
for (HBasicBlock* back_edge : GetBackEdges()) {
PopulateRecursive(back_edge);
}
}
if (!is_irreducible_loop && graph->IsCompilingOsr()) {
// When compiling in OSR mode, all loops in the compiled method may be entered
// from the interpreter. We treat this OSR entry point just like an extra entry
// to an irreducible loop, so we need to mark the method's loops as irreducible.
// This does not apply to inlined loops which do not act as OSR entry points.
if (suspend_check_ == nullptr) {
// Just building the graph in OSR mode, this loop is not inlined. We never build an
// inner graph in OSR mode as we can do OSR transition only from the outer method.
is_irreducible_loop = true;
} else {
// Look at the suspend check's environment to determine if the loop was inlined.
DCHECK(suspend_check_->HasEnvironment());
if (!suspend_check_->GetEnvironment()->IsFromInlinedInvoke()) {
is_irreducible_loop = true;
}
}
}
if (is_irreducible_loop) {
irreducible_ = true;
contains_irreducible_loop_ = true;
graph->SetHasIrreducibleLoops(true);
}
graph->SetHasLoops(true);
}
void HLoopInformation::PopulateInnerLoopUpwards(HLoopInformation* inner_loop) {
DCHECK(inner_loop->GetPreHeader()->GetLoopInformation() == this);
blocks_.Union(&inner_loop->blocks_);
HLoopInformation* outer_loop = GetPreHeader()->GetLoopInformation();
if (outer_loop != nullptr) {
outer_loop->PopulateInnerLoopUpwards(this);
}
}
HBasicBlock* HLoopInformation::GetPreHeader() const {
HBasicBlock* block = header_->GetPredecessors()[0];
DCHECK(irreducible_ || (block == header_->GetDominator()));
return block;
}
bool HLoopInformation::Contains(const HBasicBlock& block) const {
return blocks_.IsBitSet(block.GetBlockId());
}
bool HLoopInformation::IsIn(const HLoopInformation& other) const {
return other.blocks_.IsBitSet(header_->GetBlockId());
}
bool HLoopInformation::IsDefinedOutOfTheLoop(HInstruction* instruction) const {
return !blocks_.IsBitSet(instruction->GetBlock()->GetBlockId());
}
size_t HLoopInformation::GetLifetimeEnd() const {
size_t last_position = 0;
for (HBasicBlock* back_edge : GetBackEdges()) {
last_position = std::max(back_edge->GetLifetimeEnd(), last_position);
}
return last_position;
}
bool HLoopInformation::HasBackEdgeNotDominatedByHeader() const {
for (HBasicBlock* back_edge : GetBackEdges()) {
DCHECK(back_edge->GetDominator() != nullptr);
if (!header_->Dominates(back_edge)) {
return true;
}
}
return false;
}
bool HLoopInformation::DominatesAllBackEdges(HBasicBlock* block) {
for (HBasicBlock* back_edge : GetBackEdges()) {
if (!block->Dominates(back_edge)) {
return false;
}
}
return true;
}
bool HLoopInformation::HasExitEdge() const {
// Determine if this loop has at least one exit edge.
HBlocksInLoopReversePostOrderIterator it_loop(*this);
for (; !it_loop.Done(); it_loop.Advance()) {
for (HBasicBlock* successor : it_loop.Current()->GetSuccessors()) {
if (!Contains(*successor)) {
return true;
}
}
}
return false;
}
bool HBasicBlock::Dominates(HBasicBlock* other) const {
// Walk up the dominator tree from `other`, to find out if `this`
// is an ancestor.
HBasicBlock* current = other;
while (current != nullptr) {
if (current == this) {
return true;
}
current = current->GetDominator();
}
return false;
}
static void UpdateInputsUsers(HInstruction* instruction) {
HInputsRef inputs = instruction->GetInputs();
for (size_t i = 0; i < inputs.size(); ++i) {
inputs[i]->AddUseAt(instruction, i);
}
// Environment should be created later.
DCHECK(!instruction->HasEnvironment());
}
void HBasicBlock::ReplaceAndRemovePhiWith(HPhi* initial, HPhi* replacement) {
DCHECK(initial->GetBlock() == this);
InsertPhiAfter(replacement, initial);
initial->ReplaceWith(replacement);
RemovePhi(initial);
}
void HBasicBlock::ReplaceAndRemoveInstructionWith(HInstruction* initial,
HInstruction* replacement) {
DCHECK(initial->GetBlock() == this);
if (initial->IsControlFlow()) {
// We can only replace a control flow instruction with another control flow instruction.
DCHECK(replacement->IsControlFlow());
DCHECK_EQ(replacement->GetId(), -1);
DCHECK_EQ(replacement->GetType(), DataType::Type::kVoid);
DCHECK_EQ(initial->GetBlock(), this);
DCHECK_EQ(initial->GetType(), DataType::Type::kVoid);
DCHECK(initial->GetUses().empty());
DCHECK(initial->GetEnvUses().empty());
replacement->SetBlock(this);
replacement->SetId(GetGraph()->GetNextInstructionId());
instructions_.InsertInstructionBefore(replacement, initial);
UpdateInputsUsers(replacement);
} else {
InsertInstructionBefore(replacement, initial);
initial->ReplaceWith(replacement);
}
RemoveInstruction(initial);
}
static void Add(HInstructionList* instruction_list,
HBasicBlock* block,
HInstruction* instruction) {
DCHECK(instruction->GetBlock() == nullptr);
DCHECK_EQ(instruction->GetId(), -1);
instruction->SetBlock(block);
instruction->SetId(block->GetGraph()->GetNextInstructionId());
UpdateInputsUsers(instruction);
instruction_list->AddInstruction(instruction);
}
void HBasicBlock::AddInstruction(HInstruction* instruction) {
Add(&instructions_, this, instruction);
}
void HBasicBlock::AddPhi(HPhi* phi) {
Add(&phis_, this, phi);
}
void HBasicBlock::InsertInstructionBefore(HInstruction* instruction, HInstruction* cursor) {
DCHECK(!cursor->IsPhi());
DCHECK(!instruction->IsPhi());
DCHECK_EQ(instruction->GetId(), -1);
DCHECK_NE(cursor->GetId(), -1);
DCHECK_EQ(cursor->GetBlock(), this);
DCHECK(!instruction->IsControlFlow());
instruction->SetBlock(this);
instruction->SetId(GetGraph()->GetNextInstructionId());
UpdateInputsUsers(instruction);
instructions_.InsertInstructionBefore(instruction, cursor);
}
void HBasicBlock::InsertInstructionAfter(HInstruction* instruction, HInstruction* cursor) {
DCHECK(!cursor->IsPhi());
DCHECK(!instruction->IsPhi());
DCHECK_EQ(instruction->GetId(), -1);
DCHECK_NE(cursor->GetId(), -1);
DCHECK_EQ(cursor->GetBlock(), this);
DCHECK(!instruction->IsControlFlow());
DCHECK(!cursor->IsControlFlow());
instruction->SetBlock(this);
instruction->SetId(GetGraph()->GetNextInstructionId());
UpdateInputsUsers(instruction);
instructions_.InsertInstructionAfter(instruction, cursor);
}
void HBasicBlock::InsertPhiAfter(HPhi* phi, HPhi* cursor) {
DCHECK_EQ(phi->GetId(), -1);
DCHECK_NE(cursor->GetId(), -1);
DCHECK_EQ(cursor->GetBlock(), this);
phi->SetBlock(this);
phi->SetId(GetGraph()->GetNextInstructionId());
UpdateInputsUsers(phi);
phis_.InsertInstructionAfter(phi, cursor);
}
static void Remove(HInstructionList* instruction_list,
HBasicBlock* block,
HInstruction* instruction,
bool ensure_safety) {
DCHECK_EQ(block, instruction->GetBlock());
instruction->SetBlock(nullptr);
instruction_list->RemoveInstruction(instruction);
if (ensure_safety) {
DCHECK(instruction->GetUses().empty());
DCHECK(instruction->GetEnvUses().empty());
RemoveAsUser(instruction);
}
}
void HBasicBlock::RemoveInstruction(HInstruction* instruction, bool ensure_safety) {
DCHECK(!instruction->IsPhi());
Remove(&instructions_, this, instruction, ensure_safety);
}
void HBasicBlock::RemovePhi(HPhi* phi, bool ensure_safety) {
Remove(&phis_, this, phi, ensure_safety);
}
void HBasicBlock::RemoveInstructionOrPhi(HInstruction* instruction, bool ensure_safety) {
if (instruction->IsPhi()) {
RemovePhi(instruction->AsPhi(), ensure_safety);
} else {
RemoveInstruction(instruction, ensure_safety);
}
}
void HEnvironment::CopyFrom(ArrayRef<HInstruction* const> locals) {
for (size_t i = 0; i < locals.size(); i++) {
HInstruction* instruction = locals[i];
SetRawEnvAt(i, instruction);
if (instruction != nullptr) {
instruction->AddEnvUseAt(this, i);
}
}
}
void HEnvironment::CopyFrom(HEnvironment* env) {
for (size_t i = 0; i < env->Size(); i++) {
HInstruction* instruction = env->GetInstructionAt(i);
SetRawEnvAt(i, instruction);
if (instruction != nullptr) {
instruction->AddEnvUseAt(this, i);
}
}
}
void HEnvironment::CopyFromWithLoopPhiAdjustment(HEnvironment* env,
HBasicBlock* loop_header) {
DCHECK(loop_header->IsLoopHeader());
for (size_t i = 0; i < env->Size(); i++) {
HInstruction* instruction = env->GetInstructionAt(i);
SetRawEnvAt(i, instruction);
if (instruction == nullptr) {
continue;
}
if (instruction->IsLoopHeaderPhi() && (instruction->GetBlock() == loop_header)) {
// At the end of the loop pre-header, the corresponding value for instruction
// is the first input of the phi.
HInstruction* initial = instruction->AsPhi()->InputAt(0);
SetRawEnvAt(i, initial);
initial->AddEnvUseAt(this, i);
} else {
instruction->AddEnvUseAt(this, i);
}
}
}
void HEnvironment::RemoveAsUserOfInput(size_t index) const {
const HUserRecord<HEnvironment*>& env_use = vregs_[index];
HInstruction* user = env_use.GetInstruction();
auto before_env_use_node = env_use.GetBeforeUseNode();
user->env_uses_.erase_after(before_env_use_node);
user->FixUpUserRecordsAfterEnvUseRemoval(before_env_use_node);
}
void HEnvironment::ReplaceInput(HInstruction* replacement, size_t index) {
const HUserRecord<HEnvironment*>& env_use_record = vregs_[index];
HInstruction* orig_instr = env_use_record.GetInstruction();
DCHECK(orig_instr != replacement);
HUseList<HEnvironment*>::iterator before_use_node = env_use_record.GetBeforeUseNode();
// Note: fixup_end remains valid across splice_after().
auto fixup_end = replacement->env_uses_.empty() ? replacement->env_uses_.begin()
: ++replacement->env_uses_.begin();
replacement->env_uses_.splice_after(replacement->env_uses_.before_begin(),
env_use_record.GetInstruction()->env_uses_,
before_use_node);
replacement->FixUpUserRecordsAfterEnvUseInsertion(fixup_end);
orig_instr->FixUpUserRecordsAfterEnvUseRemoval(before_use_node);
}
HInstruction* HInstruction::GetNextDisregardingMoves() const {
HInstruction* next = GetNext();
while (next != nullptr && next->IsParallelMove()) {
next = next->GetNext();
}
return next;
}
HInstruction* HInstruction::GetPreviousDisregardingMoves() const {
HInstruction* previous = GetPrevious();
while (previous != nullptr && previous->IsParallelMove()) {
previous = previous->GetPrevious();
}
return previous;
}
void HInstructionList::AddInstruction(HInstruction* instruction) {
if (first_instruction_ == nullptr) {
DCHECK(last_instruction_ == nullptr);
first_instruction_ = last_instruction_ = instruction;
} else {
DCHECK(last_instruction_ != nullptr);
last_instruction_->next_ = instruction;
instruction->previous_ = last_instruction_;
last_instruction_ = instruction;
}
}
void HInstructionList::InsertInstructionBefore(HInstruction* instruction, HInstruction* cursor) {
DCHECK(Contains(cursor));
if (cursor == first_instruction_) {
cursor->previous_ = instruction;
instruction->next_ = cursor;
first_instruction_ = instruction;
} else {
instruction->previous_ = cursor->previous_;
instruction->next_ = cursor;
cursor->previous_ = instruction;
instruction->previous_->next_ = instruction;
}
}
void HInstructionList::InsertInstructionAfter(HInstruction* instruction, HInstruction* cursor) {
DCHECK(Contains(cursor));
if (cursor == last_instruction_) {
cursor->next_ = instruction;
instruction->previous_ = cursor;
last_instruction_ = instruction;
} else {
instruction->next_ = cursor->next_;
instruction->previous_ = cursor;
cursor->next_ = instruction;
instruction->next_->previous_ = instruction;
}
}
void HInstructionList::RemoveInstruction(HInstruction* instruction) {
if (instruction->previous_ != nullptr) {
instruction->previous_->next_ = instruction->next_;
}
if (instruction->next_ != nullptr) {
instruction->next_->previous_ = instruction->previous_;
}
if (instruction == first_instruction_) {
first_instruction_ = instruction->next_;
}
if (instruction == last_instruction_) {
last_instruction_ = instruction->previous_;
}
}
bool HInstructionList::Contains(HInstruction* instruction) const {
for (HInstructionIterator it(*this); !it.Done(); it.Advance()) {
if (it.Current() == instruction) {
return true;
}
}
return false;
}
bool HInstructionList::FoundBefore(const HInstruction* instruction1,
const HInstruction* instruction2) const {
DCHECK_EQ(instruction1->GetBlock(), instruction2->GetBlock());
for (HInstructionIterator it(*this); !it.Done(); it.Advance()) {
if (it.Current() == instruction1) {
return true;
}
if (it.Current() == instruction2) {
return false;
}
}
LOG(FATAL) << "Did not find an order between two instructions of the same block.";
UNREACHABLE();
}
bool HInstruction::StrictlyDominates(HInstruction* other_instruction) const {
if (other_instruction == this) {
// An instruction does not strictly dominate itself.
return false;
}
HBasicBlock* block = GetBlock();
HBasicBlock* other_block = other_instruction->GetBlock();
if (block != other_block) {
return GetBlock()->Dominates(other_instruction->GetBlock());
} else {
// If both instructions are in the same block, ensure this
// instruction comes before `other_instruction`.
if (IsPhi()) {
if (!other_instruction->IsPhi()) {
// Phis appear before non phi-instructions so this instruction
// dominates `other_instruction`.
return true;
} else {
// There is no order among phis.
LOG(FATAL) << "There is no dominance between phis of a same block.";
UNREACHABLE();
}
} else {
// `this` is not a phi.
if (other_instruction->IsPhi()) {
// Phis appear before non phi-instructions so this instruction
// does not dominate `other_instruction`.
return false;
} else {
// Check whether this instruction comes before
// `other_instruction` in the instruction list.
return block->GetInstructions().FoundBefore(this, other_instruction);
}
}
}
}
void HInstruction::RemoveEnvironment() {
RemoveEnvironmentUses(this);
environment_ = nullptr;
}
void HInstruction::ReplaceWith(HInstruction* other) {
DCHECK(other != nullptr);
// Note: fixup_end remains valid across splice_after().
auto fixup_end = other->uses_.empty() ? other->uses_.begin() : ++other->uses_.begin();
other->uses_.splice_after(other->uses_.before_begin(), uses_);
other->FixUpUserRecordsAfterUseInsertion(fixup_end);
// Note: env_fixup_end remains valid across splice_after().
auto env_fixup_end =
other->env_uses_.empty() ? other->env_uses_.begin() : ++other->env_uses_.begin();
other->env_uses_.splice_after(other->env_uses_.before_begin(), env_uses_);
other->FixUpUserRecordsAfterEnvUseInsertion(env_fixup_end);
DCHECK(uses_.empty());
DCHECK(env_uses_.empty());
}
void HInstruction::ReplaceUsesDominatedBy(HInstruction* dominator, HInstruction* replacement) {
const HUseList<HInstruction*>& uses = GetUses();
for (auto it = uses.begin(), end = uses.end(); it != end; /* ++it below */) {
HInstruction* user = it->GetUser();
size_t index = it->GetIndex();
// Increment `it` now because `*it` may disappear thanks to user->ReplaceInput().
++it;
if (dominator->StrictlyDominates(user)) {
user->ReplaceInput(replacement, index);
} else if (user->IsPhi() && !user->AsPhi()->IsCatchPhi()) {
// If the input flows from a block dominated by `dominator`, we can replace it.
// We do not perform this for catch phis as we don't have control flow support
// for their inputs.
const ArenaVector<HBasicBlock*>& predecessors = user->GetBlock()->GetPredecessors();
HBasicBlock* predecessor = predecessors[index];
if (dominator->GetBlock()->Dominates(predecessor)) {
user->ReplaceInput(replacement, index);
}
}
}
}
void HInstruction::ReplaceEnvUsesDominatedBy(HInstruction* dominator, HInstruction* replacement) {
const HUseList<HEnvironment*>& uses = GetEnvUses();
for (auto it = uses.begin(), end = uses.end(); it != end; /* ++it below */) {
HEnvironment* user = it->GetUser();
size_t index = it->GetIndex();
// Increment `it` now because `*it` may disappear thanks to user->ReplaceInput().
++it;
if (dominator->StrictlyDominates(user->GetHolder())) {
user->ReplaceInput(replacement, index);
}
}
}
void HInstruction::ReplaceInput(HInstruction* replacement, size_t index) {
HUserRecord<HInstruction*> input_use = InputRecordAt(index);
if (input_use.GetInstruction() == replacement) {
// Nothing to do.
return;
}
HUseList<HInstruction*>::iterator before_use_node = input_use.GetBeforeUseNode();
// Note: fixup_end remains valid across splice_after().
auto fixup_end =
replacement->uses_.empty() ? replacement->uses_.begin() : ++replacement->uses_.begin();
replacement->uses_.splice_after(replacement->uses_.before_begin(),
input_use.GetInstruction()->uses_,
before_use_node);
replacement->FixUpUserRecordsAfterUseInsertion(fixup_end);
input_use.GetInstruction()->FixUpUserRecordsAfterUseRemoval(before_use_node);
}
size_t HInstruction::EnvironmentSize() const {
return HasEnvironment() ? environment_->Size() : 0;
}
void HVariableInputSizeInstruction::AddInput(HInstruction* input) {
DCHECK(input->GetBlock() != nullptr);
inputs_.push_back(HUserRecord<HInstruction*>(input));
input->AddUseAt(this, inputs_.size() - 1);
}
void HVariableInputSizeInstruction::InsertInputAt(size_t index, HInstruction* input) {
inputs_.insert(inputs_.begin() + index, HUserRecord<HInstruction*>(input));
input->AddUseAt(this, index);
// Update indexes in use nodes of inputs that have been pushed further back by the insert().
for (size_t i = index + 1u, e = inputs_.size(); i < e; ++i) {
DCHECK_EQ(inputs_[i].GetUseNode()->GetIndex(), i - 1u);
inputs_[i].GetUseNode()->SetIndex(i);
}
}
void HVariableInputSizeInstruction::RemoveInputAt(size_t index) {
RemoveAsUserOfInput(index);
inputs_.erase(inputs_.begin() + index);
// Update indexes in use nodes of inputs that have been pulled forward by the erase().
for (size_t i = index, e = inputs_.size(); i < e; ++i) {
DCHECK_EQ(inputs_[i].GetUseNode()->GetIndex(), i + 1u);
inputs_[i].GetUseNode()->SetIndex(i);
}
}
void HVariableInputSizeInstruction::RemoveAllInputs() {
RemoveAsUserOfAllInputs();
DCHECK(!HasNonEnvironmentUses());
inputs_.clear();
DCHECK_EQ(0u, InputCount());
}
size_t HConstructorFence::RemoveConstructorFences(HInstruction* instruction) {
DCHECK(instruction->GetBlock() != nullptr);
// Removing constructor fences only makes sense for instructions with an object return type.
DCHECK_EQ(DataType::Type::kReference, instruction->GetType());
// Return how many instructions were removed for statistic purposes.
size_t remove_count = 0;
// Efficient implementation that simultaneously (in one pass):
// * Scans the uses list for all constructor fences.
// * Deletes that constructor fence from the uses list of `instruction`.
// * Deletes `instruction` from the constructor fence's inputs.
// * Deletes the constructor fence if it now has 0 inputs.
const HUseList<HInstruction*>& uses = instruction->GetUses();
// Warning: Although this is "const", we might mutate the list when calling RemoveInputAt.
for (auto it = uses.begin(), end = uses.end(); it != end; ) {
const HUseListNode<HInstruction*>& use_node = *it;
HInstruction* const use_instruction = use_node.GetUser();
// Advance the iterator immediately once we fetch the use_node.
// Warning: If the input is removed, the current iterator becomes invalid.
++it;
if (use_instruction->IsConstructorFence()) {
HConstructorFence* ctor_fence = use_instruction->AsConstructorFence();
size_t input_index = use_node.GetIndex();
// Process the candidate instruction for removal
// from the graph.
// Constructor fence instructions are never
// used by other instructions.
//
// If we wanted to make this more generic, it
// could be a runtime if statement.
DCHECK(!ctor_fence->HasUses());
// A constructor fence's return type is "kPrimVoid"
// and therefore it can't have any environment uses.
DCHECK(!ctor_fence->HasEnvironmentUses());
// Remove the inputs first, otherwise removing the instruction
// will try to remove its uses while we are already removing uses
// and this operation will fail.
DCHECK_EQ(instruction, ctor_fence->InputAt(input_index));
// Removing the input will also remove the `use_node`.
// (Do not look at `use_node` after this, it will be a dangling reference).
ctor_fence->RemoveInputAt(input_index);
// Once all inputs are removed, the fence is considered dead and
// is removed.
if (ctor_fence->InputCount() == 0u) {
ctor_fence->GetBlock()->RemoveInstruction(ctor_fence);
++remove_count;
}
}
}
if (kIsDebugBuild) {
// Post-condition checks:
// * None of the uses of `instruction` are a constructor fence.
// * The `instruction` itself did not get removed from a block.
for (const HUseListNode<HInstruction*>& use_node : instruction->GetUses()) {
CHECK(!use_node.GetUser()->IsConstructorFence());
}
CHECK(instruction->GetBlock() != nullptr);
}
return remove_count;
}
void HConstructorFence::Merge(HConstructorFence* other) {
// Do not delete yourself from the graph.
DCHECK(this != other);
// Don't try to merge with an instruction not associated with a block.
DCHECK(other->GetBlock() != nullptr);
// A constructor fence's return type is "kPrimVoid"
// and therefore it cannot have any environment uses.
DCHECK(!other->HasEnvironmentUses());
auto has_input = [](HInstruction* haystack, HInstruction* needle) {
// Check if `haystack` has `needle` as any of its inputs.
for (size_t input_count = 0; input_count < haystack->InputCount(); ++input_count) {
if (haystack->InputAt(input_count) == needle) {
return true;
}
}
return false;
};
// Add any inputs from `other` into `this` if it wasn't already an input.
for (size_t input_count = 0; input_count < other->InputCount(); ++input_count) {
HInstruction* other_input = other->InputAt(input_count);
if (!has_input(this, other_input)) {
AddInput(other_input);
}
}
other->GetBlock()->RemoveInstruction(other);
}
HInstruction* HConstructorFence::GetAssociatedAllocation(bool ignore_inputs) {
HInstruction* new_instance_inst = GetPrevious();
// Check if the immediately preceding instruction is a new-instance/new-array.
// Otherwise this fence is for protecting final fields.
if (new_instance_inst != nullptr &&
(new_instance_inst->IsNewInstance() || new_instance_inst->IsNewArray())) {
if (ignore_inputs) {
// If inputs are ignored, simply check if the predecessor is
// *any* HNewInstance/HNewArray.
//
// Inputs are normally only ignored for prepare_for_register_allocation,
// at which point *any* prior HNewInstance/Array can be considered
// associated.
return new_instance_inst;
} else {
// Normal case: There must be exactly 1 input and the previous instruction
// must be that input.
if (InputCount() == 1u && InputAt(0) == new_instance_inst) {
return new_instance_inst;
}
}
}
return nullptr;
}
#define DEFINE_ACCEPT(name, super) \
void H##name::Accept(HGraphVisitor* visitor) { \
visitor->Visit##name(this); \
}
FOR_EACH_CONCRETE_INSTRUCTION(DEFINE_ACCEPT)
#undef DEFINE_ACCEPT
void HGraphVisitor::VisitInsertionOrder() {
const ArenaVector<HBasicBlock*>& blocks = graph_->GetBlocks();
for (HBasicBlock* block : blocks) {
if (block != nullptr) {
VisitBasicBlock(block);
}
}
}
void HGraphVisitor::VisitReversePostOrder() {
for (HBasicBlock* block : graph_->GetReversePostOrder()) {
VisitBasicBlock(block);
}
}
void HGraphVisitor::VisitBasicBlock(HBasicBlock* block) {
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
it.Current()->Accept(this);
}
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
it.Current()->Accept(this);
}
}
HConstant* HTypeConversion::TryStaticEvaluation() const {
HGraph* graph = GetBlock()->GetGraph();
if (GetInput()->IsIntConstant()) {
int32_t value = GetInput()->AsIntConstant()->GetValue();
switch (GetResultType()) {
case DataType::Type::kInt8:
return graph->GetIntConstant(static_cast<int8_t>(value), GetDexPc());
case DataType::Type::kUint8:
return graph->GetIntConstant(static_cast<uint8_t>(value), GetDexPc());
case DataType::Type::kInt16:
return graph->GetIntConstant(static_cast<int16_t>(value), GetDexPc());
case DataType::Type::kUint16:
return graph->GetIntConstant(static_cast<uint16_t>(value), GetDexPc());
case DataType::Type::kInt64:
return graph->GetLongConstant(static_cast<int64_t>(value), GetDexPc());
case DataType::Type::kFloat32:
return graph->GetFloatConstant(static_cast<float>(value), GetDexPc());
case DataType::Type::kFloat64:
return graph->GetDoubleConstant(static_cast<double>(value), GetDexPc());
default:
return nullptr;
}
} else if (GetInput()->IsLongConstant()) {
int64_t value = GetInput()->AsLongConstant()->GetValue();
switch (GetResultType()) {
case DataType::Type::kInt8:
return graph->GetIntConstant(static_cast<int8_t>(value), GetDexPc());
case DataType::Type::kUint8:
return graph->GetIntConstant(static_cast<uint8_t>(value), GetDexPc());
case DataType::Type::kInt16:
return graph->GetIntConstant(static_cast<int16_t>(value), GetDexPc());
case DataType::Type::kUint16:
return graph->GetIntConstant(static_cast<uint16_t>(value), GetDexPc());
case DataType::Type::kInt32:
return graph->GetIntConstant(static_cast<int32_t>(value), GetDexPc());
case DataType::Type::kFloat32:
return graph->GetFloatConstant(static_cast<float>(value), GetDexPc());
case DataType::Type::kFloat64:
return graph->GetDoubleConstant(static_cast<double>(value), GetDexPc());
default:
return nullptr;
}
} else if (GetInput()->IsFloatConstant()) {
float value = GetInput()->AsFloatConstant()->GetValue();
switch (GetResultType()) {
case DataType::Type::kInt32:
if (std::isnan(value))
return graph->GetIntConstant(0, GetDexPc());
if (value >= kPrimIntMax)
return graph->GetIntConstant(kPrimIntMax, GetDexPc());
if (value <= kPrimIntMin)
return graph->GetIntConstant(kPrimIntMin, GetDexPc());
return graph->GetIntConstant(static_cast<int32_t>(value), GetDexPc());
case DataType::Type::kInt64:
if (std::isnan(value))
return graph->GetLongConstant(0, GetDexPc());
if (value >= kPrimLongMax)
return graph->GetLongConstant(kPrimLongMax, GetDexPc());
if (value <= kPrimLongMin)
return graph->GetLongConstant(kPrimLongMin, GetDexPc());
return graph->GetLongConstant(static_cast<int64_t>(value), GetDexPc());
case DataType::Type::kFloat64:
return graph->GetDoubleConstant(static_cast<double>(value), GetDexPc());
default:
return nullptr;
}
} else if (GetInput()->IsDoubleConstant()) {
double value = GetInput()->AsDoubleConstant()->GetValue();
switch (GetResultType()) {
case DataType::Type::kInt32:
if (std::isnan(value))
return graph->GetIntConstant(0, GetDexPc());
if (value >= kPrimIntMax)
return graph->GetIntConstant(kPrimIntMax, GetDexPc());
if (value <= kPrimLongMin)
return graph->GetIntConstant(kPrimIntMin, GetDexPc());
return graph->GetIntConstant(static_cast<int32_t>(value), GetDexPc());
case DataType::Type::kInt64:
if (std::isnan(value))
return graph->GetLongConstant(0, GetDexPc());
if (value >= kPrimLongMax)
return graph->GetLongConstant(kPrimLongMax, GetDexPc());
if (value <= kPrimLongMin)
return graph->GetLongConstant(kPrimLongMin, GetDexPc());
return graph->GetLongConstant(static_cast<int64_t>(value), GetDexPc());
case DataType::Type::kFloat32:
return graph->GetFloatConstant(static_cast<float>(value), GetDexPc());
default:
return nullptr;
}
}
return nullptr;
}
HConstant* HUnaryOperation::TryStaticEvaluation() const {
if (GetInput()->IsIntConstant()) {
return Evaluate(GetInput()->AsIntConstant());
} else if (GetInput()->IsLongConstant()) {
return Evaluate(GetInput()->AsLongConstant());
} else if (kEnableFloatingPointStaticEvaluation) {
if (GetInput()->IsFloatConstant()) {
return Evaluate(GetInput()->AsFloatConstant());
} else if (GetInput()->IsDoubleConstant()) {
return Evaluate(GetInput()->AsDoubleConstant());
}
}
return nullptr;
}
HConstant* HBinaryOperation::TryStaticEvaluation() const {
if (GetLeft()->IsIntConstant() && GetRight()->IsIntConstant()) {
return Evaluate(GetLeft()->AsIntConstant(), GetRight()->AsIntConstant());
} else if (GetLeft()->IsLongConstant()) {
if (GetRight()->IsIntConstant()) {
// The binop(long, int) case is only valid for shifts and rotations.
DCHECK(IsShl() || IsShr() || IsUShr() || IsRor()) << DebugName();
return Evaluate(GetLeft()->AsLongConstant(), GetRight()->AsIntConstant());
} else if (GetRight()->IsLongConstant()) {
return Evaluate(GetLeft()->AsLongConstant(), GetRight()->AsLongConstant());
}
} else if (GetLeft()->IsNullConstant() && GetRight()->IsNullConstant()) {
// The binop(null, null) case is only valid for equal and not-equal conditions.
DCHECK(IsEqual() || IsNotEqual()) << DebugName();
return Evaluate(GetLeft()->AsNullConstant(), GetRight()->AsNullConstant());
} else if (kEnableFloatingPointStaticEvaluation) {
if (GetLeft()->IsFloatConstant() && GetRight()->IsFloatConstant()) {
return Evaluate(GetLeft()->AsFloatConstant(), GetRight()->AsFloatConstant());
} else if (GetLeft()->IsDoubleConstant() && GetRight()->IsDoubleConstant()) {
return Evaluate(GetLeft()->AsDoubleConstant(), GetRight()->AsDoubleConstant());
}
}
return nullptr;
}
HConstant* HBinaryOperation::GetConstantRight() const {
if (GetRight()->IsConstant()) {
return GetRight()->AsConstant();
} else if (IsCommutative() && GetLeft()->IsConstant()) {
return GetLeft()->AsConstant();
} else {
return nullptr;
}
}
// If `GetConstantRight()` returns one of the input, this returns the other
// one. Otherwise it returns null.
HInstruction* HBinaryOperation::GetLeastConstantLeft() const {
HInstruction* most_constant_right = GetConstantRight();
if (most_constant_right == nullptr) {
return nullptr;
} else if (most_constant_right == GetLeft()) {
return GetRight();
} else {
return GetLeft();
}
}
std::ostream& operator<<(std::ostream& os, const ComparisonBias& rhs) {
switch (rhs) {
case ComparisonBias::kNoBias:
return os << "no_bias";
case ComparisonBias::kGtBias:
return os << "gt_bias";
case ComparisonBias::kLtBias:
return os << "lt_bias";
default:
LOG(FATAL) << "Unknown ComparisonBias: " << static_cast<int>(rhs);
UNREACHABLE();
}
}
bool HCondition::IsBeforeWhenDisregardMoves(HInstruction* instruction) const {
return this == instruction->GetPreviousDisregardingMoves();
}
bool HInstruction::Equals(const HInstruction* other) const {
if (GetKind() != other->GetKind()) return false;
if (GetType() != other->GetType()) return false;
if (!InstructionDataEquals(other)) return false;
HConstInputsRef inputs = GetInputs();
HConstInputsRef other_inputs = other->GetInputs();
if (inputs.size() != other_inputs.size()) return false;
for (size_t i = 0; i != inputs.size(); ++i) {
if (inputs[i] != other_inputs[i]) return false;
}
DCHECK_EQ(ComputeHashCode(), other->ComputeHashCode());
return true;
}
std::ostream& operator<<(std::ostream& os, const HInstruction::InstructionKind& rhs) {
#define DECLARE_CASE(type, super) case HInstruction::k##type: os << #type; break;
switch (rhs) {
FOR_EACH_CONCRETE_INSTRUCTION(DECLARE_CASE)
default:
os << "Unknown instruction kind " << static_cast<int>(rhs);
break;
}
#undef DECLARE_CASE
return os;
}
void HInstruction::MoveBefore(HInstruction* cursor, bool do_checks) {
if (do_checks) {
DCHECK(!IsPhi());
DCHECK(!IsControlFlow());
DCHECK(CanBeMoved() ||
// HShouldDeoptimizeFlag can only be moved by CHAGuardOptimization.
IsShouldDeoptimizeFlag());
DCHECK(!cursor->IsPhi());
}
next_->previous_ = previous_;
if (previous_ != nullptr) {
previous_->next_ = next_;
}
if (block_->instructions_.first_instruction_ == this) {
block_->instructions_.first_instruction_ = next_;
}
DCHECK_NE(block_->instructions_.last_instruction_, this);
previous_ = cursor->previous_;
if (previous_ != nullptr) {
previous_->next_ = this;
}
next_ = cursor;
cursor->previous_ = this;
block_ = cursor->block_;
if (block_->instructions_.first_instruction_ == cursor) {
block_->instructions_.first_instruction_ = this;
}
}
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.
auto uses_it = GetUses().begin();
auto uses_end = GetUses().end();
HBasicBlock* target_block = uses_it->GetUser()->GetBlock();
++uses_it;
while (uses_it != uses_end && uses_it->GetUser()->GetBlock() == target_block) {
++uses_it;
}
if (uses_it != uses_end) {
// This instruction has uses in two or more blocks. Find the common dominator.
CommonDominator finder(target_block);
for (; uses_it != uses_end; ++uses_it) {
finder.Update(uses_it->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 (const HUseListNode<HInstruction*>& use : GetUses()) {
if (use.GetUser()->GetBlock() == target_block &&
(insert_pos == nullptr || use.GetUser()->StrictlyDominates(insert_pos))) {
insert_pos = use.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);
HBasicBlock* new_block =
new (GetGraph()->GetAllocator()) HBasicBlock(GetGraph(), cursor->GetDexPc());
new_block->instructions_.first_instruction_ = cursor;
new_block->instructions_.last_instruction_ = instructions_.last_instruction_;
instructions_.last_instruction_ = cursor->previous_;
if (cursor->previous_ == nullptr) {
instructions_.first_instruction_ = nullptr;
} else {
cursor->previous_->next_ = nullptr;
cursor->previous_ = nullptr;
}
new_block->instructions_.SetBlockOfInstructions(new_block);
AddInstruction(new (GetGraph()->GetAllocator()) HGoto(new_block->GetDexPc()));
for (HBasicBlock* successor : GetSuccessors()) {
successor->predecessors_[successor->GetPredecessorIndexOf(this)] = new_block;
}
new_block->successors_.swap(successors_);
DCHECK(successors_.empty());
AddSuccessor(new_block);
GetGraph()->AddBlock(new_block);
return new_block;
}
HBasicBlock* HBasicBlock::CreateImmediateDominator() {
DCHECK(!graph_->IsInSsaForm()) << "Support for SSA form not implemented.";
DCHECK(!IsCatchBlock()) << "Support for updating try/catch information not implemented.";
HBasicBlock* new_block = new (GetGraph()->GetAllocator()) HBasicBlock(GetGraph(), GetDexPc());
for (HBasicBlock* predecessor : GetPredecessors()) {
predecessor->successors_[predecessor->GetSuccessorIndexOf(this)] = new_block;
}
new_block->predecessors_.swap(predecessors_);
DCHECK(predecessors_.empty());
AddPredecessor(new_block);
GetGraph()->AddBlock(new_block);
return new_block;
}
HBasicBlock* HBasicBlock::SplitBeforeForInlining(HInstruction* cursor) {
DCHECK_EQ(cursor->GetBlock(), this);
HBasicBlock* new_block =
new (GetGraph()->GetAllocator()) HBasicBlock(GetGraph(), cursor->GetDexPc());
new_block->instructions_.first_instruction_ = cursor;
new_block->instructions_.last_instruction_ = instructions_.last_instruction_;
instructions_.last_instruction_ = cursor->previous_;
if (cursor->previous_ == nullptr) {
instructions_.first_instruction_ = nullptr;
} else {
cursor->previous_->next_ = nullptr;
cursor->previous_ = nullptr;
}
new_block->instructions_.SetBlockOfInstructions(new_block);
for (HBasicBlock* successor : GetSuccessors()) {
successor->predecessors_[successor->GetPredecessorIndexOf(this)] = new_block;
}
new_block->successors_.swap(successors_);
DCHECK(successors_.empty());
for (HBasicBlock* dominated : GetDominatedBlocks()) {
dominated->dominator_ = new_block;
}
new_block->dominated_blocks_.swap(dominated_blocks_);
DCHECK(dominated_blocks_.empty());
return new_block;
}
HBasicBlock* HBasicBlock::SplitAfterForInlining(HInstruction* cursor) {
DCHECK(!cursor->IsControlFlow());
DCHECK_NE(instructions_.last_instruction_, cursor);
DCHECK_EQ(cursor->GetBlock(), this);
HBasicBlock* new_block = new (GetGraph()->GetAllocator()) HBasicBlock(GetGraph(), GetDexPc());
new_block->instructions_.first_instruction_ = cursor->GetNext();
new_block->instructions_.last_instruction_ = instructions_.last_instruction_;
cursor->next_->previous_ = nullptr;
cursor->next_ = nullptr;
instructions_.last_instruction_ = cursor;
new_block->instructions_.SetBlockOfInstructions(new_block);
for (HBasicBlock* successor : GetSuccessors()) {
successor->predecessors_[successor->GetPredecessorIndexOf(this)] = new_block;
}
new_block->successors_.swap(successors_);
DCHECK(successors_.empty());
for (HBasicBlock* dominated : GetDominatedBlocks()) {
dominated->dominator_ = new_block;
}
new_block->dominated_blocks_.swap(dominated_blocks_);
DCHECK(dominated_blocks_.empty());
return new_block;
}
const HTryBoundary* HBasicBlock::ComputeTryEntryOfSuccessors() const {
if (EndsWithTryBoundary()) {
HTryBoundary* try_boundary = GetLastInstruction()->AsTryBoundary();
if (try_boundary->IsEntry()) {
DCHECK(!IsTryBlock());
return try_boundary;
} else {
DCHECK(IsTryBlock());
DCHECK(try_catch_information_->GetTryEntry().HasSameExceptionHandlersAs(*try_boundary));
return nullptr;
}
} else if (IsTryBlock()) {
return &try_catch_information_->GetTryEntry();
} else {
return nullptr;
}
}
bool HBasicBlock::HasThrowingInstructions() const {
for (HInstructionIterator it(GetInstructions()); !it.Done(); it.Advance()) {
if (it.Current()->CanThrow()) {
return true;
}
}
return false;
}
static bool HasOnlyOneInstruction(const HBasicBlock& block) {
return block.GetPhis().IsEmpty()
&& !block.GetInstructions().IsEmpty()
&& block.GetFirstInstruction() == block.GetLastInstruction();
}
bool HBasicBlock::IsSingleGoto() const {
return HasOnlyOneInstruction(*this) && GetLastInstruction()->IsGoto();
}
bool HBasicBlock::IsSingleReturn() const {
return HasOnlyOneInstruction(*this) && GetLastInstruction()->IsReturn();
}
bool HBasicBlock::IsSingleReturnOrReturnVoidAllowingPhis() const {
return (GetFirstInstruction() == GetLastInstruction()) &&
(GetLastInstruction()->IsReturn() || GetLastInstruction()->IsReturnVoid());
}
bool HBasicBlock::IsSingleTryBoundary() const {
return HasOnlyOneInstruction(*this) && GetLastInstruction()->IsTryBoundary();
}
bool HBasicBlock::EndsWithControlFlowInstruction() const {
return !GetInstructions().IsEmpty() && GetLastInstruction()->IsControlFlow();
}
bool HBasicBlock::EndsWithReturn() const {
return !GetInstructions().IsEmpty() &&
(GetLastInstruction()->IsReturn() || GetLastInstruction()->IsReturnVoid());
}
bool HBasicBlock::EndsWithIf() const {
return !GetInstructions().IsEmpty() && GetLastInstruction()->IsIf();
}
bool HBasicBlock::EndsWithTryBoundary() const {
return !GetInstructions().IsEmpty() && GetLastInstruction()->IsTryBoundary();
}
bool HBasicBlock::HasSinglePhi() const {
return !GetPhis().IsEmpty() && GetFirstPhi()->GetNext() == nullptr;
}
ArrayRef<HBasicBlock* const> HBasicBlock::GetNormalSuccessors() const {
if (EndsWithTryBoundary()) {
// The normal-flow successor of HTryBoundary is always stored at index zero.
DCHECK_EQ(successors_[0], GetLastInstruction()->AsTryBoundary()->GetNormalFlowSuccessor());
return ArrayRef<HBasicBlock* const>(successors_).SubArray(0u, 1u);
} else {
// All successors of blocks not ending with TryBoundary are normal.
return ArrayRef<HBasicBlock* const>(successors_);
}
}
ArrayRef<HBasicBlock* const> HBasicBlock::GetExceptionalSuccessors() const {
if (EndsWithTryBoundary()) {
return GetLastInstruction()->AsTryBoundary()->GetExceptionHandlers();
} else {
// Blocks not ending with TryBoundary do not have exceptional successors.
return ArrayRef<HBasicBlock* const>();
}
}
bool HTryBoundary::HasSameExceptionHandlersAs(const HTryBoundary& other) const {
ArrayRef<HBasicBlock* const> handlers1 = GetExceptionHandlers();
ArrayRef<HBasicBlock* const> handlers2 = other.GetExceptionHandlers();
size_t length = handlers1.size();
if (length != handlers2.size()) {
return false;
}
// Exception handlers need to be stored in the same order.
for (size_t i = 0; i < length; ++i) {
if (handlers1[i] != handlers2[i]) {
return false;
}
}
return true;
}
size_t HInstructionList::CountSize() const {
size_t size = 0;
HInstruction* current = first_instruction_;
for (; current != nullptr; current = current->GetNext()) {
size++;
}
return size;
}
void HInstructionList::SetBlockOfInstructions(HBasicBlock* block) const {
for (HInstruction* current = first_instruction_;
current != nullptr;
current = current->GetNext()) {
current->SetBlock(block);
}
}
void HInstructionList::AddAfter(HInstruction* cursor, const HInstructionList& instruction_list) {
DCHECK(Contains(cursor));
if (!instruction_list.IsEmpty()) {
if (cursor == last_instruction_) {
last_instruction_ = instruction_list.last_instruction_;
} else {
cursor->next_->previous_ = instruction_list.last_instruction_;
}
instruction_list.last_instruction_->next_ = cursor->next_;
cursor->next_ = instruction_list.first_instruction_;
instruction_list.first_instruction_->previous_ = cursor;
}
}
void HInstructionList::AddBefore(HInstruction* cursor, const HInstructionList& instruction_list) {
DCHECK(Contains(cursor));
if (!instruction_list.IsEmpty()) {
if (cursor == first_instruction_) {
first_instruction_ = instruction_list.first_instruction_;
} else {
cursor->previous_->next_ = instruction_list.first_instruction_;
}
instruction_list.last_instruction_->next_ = cursor;
instruction_list.first_instruction_->previous_ = cursor->previous_;
cursor->previous_ = instruction_list.last_instruction_;
}
}
void HInstructionList::Add(const HInstructionList& instruction_list) {
if (IsEmpty()) {
first_instruction_ = instruction_list.first_instruction_;
last_instruction_ = instruction_list.last_instruction_;
} else {
AddAfter(last_instruction_, instruction_list);
}
}
// Should be called on instructions in a dead block in post order. This method
// assumes `insn` has been removed from all users with the exception of catch
// phis because of missing exceptional edges in the graph. It removes the
// instruction from catch phi uses, together with inputs of other catch phis in
// the catch block at the same index, as these must be dead too.
static void RemoveUsesOfDeadInstruction(HInstruction* insn) {
DCHECK(!insn->HasEnvironmentUses());
while (insn->HasNonEnvironmentUses()) {
const HUseListNode<HInstruction*>& use = insn->GetUses().front();
size_t use_index = use.GetIndex();
HBasicBlock* user_block = use.GetUser()->GetBlock();
DCHECK(use.GetUser()->IsPhi() && user_block->IsCatchBlock());
for (HInstructionIterator phi_it(user_block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
phi_it.Current()->AsPhi()->RemoveInputAt(use_index);
}
}
}
void HBasicBlock::DisconnectAndDelete() {
// Dominators must be removed after all the blocks they dominate. This way
// a loop header is removed last, a requirement for correct loop information
// iteration.
DCHECK(dominated_blocks_.empty());
// The following steps gradually remove the block from all its dependants in
// post order (b/27683071).
// (1) Store a basic block that we'll use in step (5) to find loops to be updated.
// We need to do this before step (4) which destroys the predecessor list.
HBasicBlock* loop_update_start = this;
if (IsLoopHeader()) {
HLoopInformation* loop_info = GetLoopInformation();
// All other blocks in this loop should have been removed because the header
// was their dominator.
// Note that we do not remove `this` from `loop_info` as it is unreachable.
DCHECK(!loop_info->IsIrreducible());
DCHECK_EQ(loop_info->GetBlocks().NumSetBits(), 1u);
DCHECK_EQ(static_cast<uint32_t>(loop_info->GetBlocks().GetHighestBitSet()), GetBlockId());
loop_update_start = loop_info->GetPreHeader();
}
// (2) Disconnect the block from its successors and update their phis.
for (HBasicBlock* successor : successors_) {
// Delete this block from the list of predecessors.
size_t this_index = successor->GetPredecessorIndexOf(this);
successor->predecessors_.erase(successor->predecessors_.begin() + this_index);
// Check that `successor` has other predecessors, otherwise `this` is the
// dominator of `successor` which violates the order DCHECKed at the top.
DCHECK(!successor->predecessors_.empty());
// Remove this block's entries in the successor's phis. Skip exceptional
// successors because catch phi inputs do not correspond to predecessor
// blocks but throwing instructions. The inputs of the catch phis will be
// updated in step (3).
if (!successor->IsCatchBlock()) {
if (successor->predecessors_.size() == 1u) {
// The successor has just one predecessor left. Replace phis with the only
// remaining input.
for (HInstructionIterator phi_it(successor->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
HPhi* phi = phi_it.Current()->AsPhi();
phi->ReplaceWith(phi->InputAt(1 - this_index));
successor->RemovePhi(phi);
}
} else {
for (HInstructionIterator phi_it(successor->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
phi_it.Current()->AsPhi()->RemoveInputAt(this_index);
}
}
}
}
successors_.clear();
// (3) Remove instructions and phis. Instructions should have no remaining uses
// except in catch phis. If an instruction is used by a catch phi at `index`,
// remove `index`-th input of all phis in the catch block since they are
// guaranteed dead. Note that we may miss dead inputs this way but the
// graph will always remain consistent.
for (HBackwardInstructionIterator it(GetInstructions()); !it.Done(); it.Advance()) {
HInstruction* insn = it.Current();
RemoveUsesOfDeadInstruction(insn);
RemoveInstruction(insn);
}
for (HInstructionIterator it(GetPhis()); !it.Done(); it.Advance()) {
HPhi* insn = it.Current()->AsPhi();
RemoveUsesOfDeadInstruction(insn);
RemovePhi(insn);
}
// (4) Disconnect the block from its predecessors and update their
// control-flow instructions.
for (HBasicBlock* predecessor : predecessors_) {
// We should not see any back edges as they would have been removed by step (3).
DCHECK(!IsInLoop() || !GetLoopInformation()->IsBackEdge(*predecessor));
HInstruction* last_instruction = predecessor->GetLastInstruction();
if (last_instruction->IsTryBoundary() && !IsCatchBlock()) {
// This block is the only normal-flow successor of the TryBoundary which
// makes `predecessor` dead. Since DCE removes blocks in post order,
// exception handlers of this TryBoundary were already visited and any
// remaining handlers therefore must be live. We remove `predecessor` from
// their list of predecessors.
DCHECK_EQ(last_instruction->AsTryBoundary()->GetNormalFlowSuccessor(), this);
while (predecessor->GetSuccessors().size() > 1) {
HBasicBlock* handler = predecessor->GetSuccessors()[1];
DCHECK(handler->IsCatchBlock());
predecessor->RemoveSuccessor(handler);
handler->RemovePredecessor(predecessor);
}
}
predecessor->RemoveSuccessor(this);
uint32_t num_pred_successors = predecessor->GetSuccessors().size();
if (num_pred_successors == 1u) {
// If we have one successor after removing one, then we must have
// had an HIf, HPackedSwitch or HTryBoundary, as they have more than one
// successor. Replace those with a HGoto.
DCHECK(last_instruction->IsIf() ||
last_instruction->IsPackedSwitch() ||
(last_instruction->IsTryBoundary() && IsCatchBlock()));
predecessor->RemoveInstruction(last_instruction);
predecessor->AddInstruction(new (graph_->GetAllocator()) HGoto(last_instruction->GetDexPc()));
} else if (num_pred_successors == 0u) {
// The predecessor has no remaining successors and therefore must be dead.
// We deliberately leave it without a control-flow instruction so that the
// GraphChecker fails unless it is not removed during the pass too.
predecessor->RemoveInstruction(last_instruction);
} else {
// There are multiple successors left. The removed block might be a successor
// of a PackedSwitch which will be completely removed (perhaps replaced with
// a Goto), or we are deleting a catch block from a TryBoundary. In either
// case, leave `last_instruction` as is for now.
DCHECK(last_instruction->IsPackedSwitch() ||
(last_instruction->IsTryBoundary() && IsCatchBlock()));
}
}
predecessors_.clear();
// (5) Remove the block from all loops it is included in. Skip the inner-most
// loop if this is the loop header (see definition of `loop_update_start`)
// because the loop header's predecessor list has been destroyed in step (4).
for (HLoopInformationOutwardIterator it(*loop_update_start); !it.Done(); it.Advance()) {
HLoopInformation* loop_info = it.Current();
loop_info->Remove(this);
if (loop_info->IsBackEdge(*this)) {
// If this was the last back edge of the loop, we deliberately leave the
// loop in an inconsistent state and will fail GraphChecker unless the
// entire loop is removed during the pass.
loop_info->RemoveBackEdge(this);
}
}
// (6) Disconnect from the dominator.
dominator_->RemoveDominatedBlock(this);
SetDominator(nullptr);
// (7) Delete from the graph, update reverse post order.
graph_->DeleteDeadEmptyBlock(this);
SetGraph(nullptr);
}
void HBasicBlock::MergeInstructionsWith(HBasicBlock* other) {
DCHECK(EndsWithControlFlowInstruction());
RemoveInstruction(GetLastInstruction());
instructions_.Add(other->GetInstructions());
other->instructions_.SetBlockOfInstructions(this);
other->instructions_.Clear();
}
void HBasicBlock::MergeWith(HBasicBlock* other) {
DCHECK_EQ(GetGraph(), other->GetGraph());
DCHECK(ContainsElement(dominated_blocks_, other));
DCHECK_EQ(GetSingleSuccessor(), other);
DCHECK_EQ(other->GetSinglePredecessor(), this);
DCHECK(other->GetPhis().IsEmpty());
// Move instructions from `other` to `this`.
MergeInstructionsWith(other);
// Remove `other` from the loops it is included in.
for (HLoopInformationOutwardIterator it(*other); !it.Done(); it.Advance()) {
HLoopInformation* loop_info = it.Current();
loop_info->Remove(other);
if (loop_info->IsBackEdge(*other)) {
loop_info->ReplaceBackEdge(other, this);
}
}
// Update links to the successors of `other`.
successors_.clear();
for (HBasicBlock* successor : other->GetSuccessors()) {
successor->predecessors_[successor->GetPredecessorIndexOf(other)] = this;
}
successors_.swap(other->successors_);
DCHECK(other->successors_.empty());
// Update the dominator tree.
RemoveDominatedBlock(other);
for (HBasicBlock* dominated : other->GetDominatedBlocks()) {
dominated->SetDominator(this);
}
dominated_blocks_.insert(
dominated_blocks_.end(), other->dominated_blocks_.begin(), other->dominated_blocks_.end());
other->dominated_blocks_.clear();
other->dominator_ = nullptr;
// Clear the list of predecessors of `other` in preparation of deleting it.
other->predecessors_.clear();
// Delete `other` from the graph. The function updates reverse post order.
graph_->DeleteDeadEmptyBlock(other);
other->SetGraph(nullptr);
}
void HBasicBlock::MergeWithInlined(HBasicBlock* other) {
DCHECK_NE(GetGraph(), other->GetGraph());
DCHECK(GetDominatedBlocks().empty());
DCHECK(GetSuccessors().empty());
DCHECK(!EndsWithControlFlowInstruction());
DCHECK(other->GetSinglePredecessor()->IsEntryBlock());
DCHECK(other->GetPhis().IsEmpty());
DCHECK(!other->IsInLoop());
// Move instructions from `other` to `this`.
instructions_.Add(other->GetInstructions());
other->instructions_.SetBlockOfInstructions(this);
// Update links to the successors of `other`.
successors_.clear();
for (HBasicBlock* successor : other->GetSuccessors()) {
successor->predecessors_[successor->GetPredecessorIndexOf(other)] = this;
}
successors_.swap(other->successors_);
DCHECK(other->successors_.empty());
// Update the dominator tree.
for (HBasicBlock* dominated : other->GetDominatedBlocks()) {
dominated->SetDominator(this);
}
dominated_blocks_.insert(
dominated_blocks_.end(), other->dominated_blocks_.begin(), other->dominated_blocks_.end());
other->dominated_blocks_.clear();
other->dominator_ = nullptr;
other->graph_ = nullptr;
}
void HBasicBlock::ReplaceWith(HBasicBlock* other) {
while (!GetPredecessors().empty()) {
HBasicBlock* predecessor = GetPredecessors()[0];
predecessor->ReplaceSuccessor(this, other);
}
while (!GetSuccessors().empty()) {
HBasicBlock* successor = GetSuccessors()[0];
successor->ReplacePredecessor(this, other);
}
for (HBasicBlock* dominated : GetDominatedBlocks()) {
other->AddDominatedBlock(dominated);
}
GetDominator()->ReplaceDominatedBlock(this, other);
other->SetDominator(GetDominator());
dominator_ = nullptr;
graph_ = nullptr;
}
void HGraph::DeleteDeadEmptyBlock(HBasicBlock* block) {
DCHECK_EQ(block->GetGraph(), this);
DCHECK(block->GetSuccessors().empty());
DCHECK(block->GetPredecessors().empty());
DCHECK(block->GetDominatedBlocks().empty());
DCHECK(block->GetDominator() == nullptr);
DCHECK(block->GetInstructions().IsEmpty());
DCHECK(block->GetPhis().IsEmpty());
if (block->IsExitBlock()) {
SetExitBlock(nullptr);
}
RemoveElement(reverse_post_order_, block);
blocks_[block->GetBlockId()] = nullptr;
block->SetGraph(nullptr);
}
void HGraph::UpdateLoopAndTryInformationOfNewBlock(HBasicBlock* block,
HBasicBlock* reference,
bool replace_if_back_edge) {
if (block->IsLoopHeader()) {
// Clear the information of which blocks are contained in that loop. Since the
// information is stored as a bit vector based on block ids, we have to update
// it, as those block ids were specific to the callee graph and we are now adding
// these blocks to the caller graph.
block->GetLoopInformation()->ClearAllBlocks();
}
// If not already in a loop, update the loop information.
if (!block->IsInLoop()) {
block->SetLoopInformation(reference->GetLoopInformation());
}
// If the block is in a loop, update all its outward loops.
HLoopInformation* loop_info = block->GetLoopInformation();
if (loop_info != nullptr) {
for (HLoopInformationOutwardIterator loop_it(*block);
!loop_it.Done();
loop_it.Advance()) {
loop_it.Current()->Add(block);
}
if (replace_if_back_edge && loop_info->IsBackEdge(*reference)) {
loop_info->ReplaceBackEdge(reference, block);
}
}
// Copy TryCatchInformation if `reference` is a try block, not if it is a catch block.
TryCatchInformation* try_catch_info = reference->IsTryBlock()
? reference->GetTryCatchInformation()
: nullptr;
block->SetTryCatchInformation(try_catch_info);
}
HInstruction* HGraph::InlineInto(HGraph* outer_graph, HInvoke* invoke) {
DCHECK(HasExitBlock()) << "Unimplemented scenario";
// Update the environments in this graph to have the invoke's environment
// as parent.
{
// Skip the entry block, we do not need to update the entry's suspend check.
for (HBasicBlock* block : GetReversePostOrderSkipEntryBlock()) {
for (HInstructionIterator instr_it(block->GetInstructions());
!instr_it.Done();
instr_it.Advance()) {
HInstruction* current = instr_it.Current();
if (current->NeedsEnvironment()) {
DCHECK(current->HasEnvironment());
current->GetEnvironment()->SetAndCopyParentChain(
outer_graph->GetAllocator(), invoke->GetEnvironment());
}
}
}
}
outer_graph->UpdateMaximumNumberOfOutVRegs(GetMaximumNumberOfOutVRegs());
if (HasBoundsChecks()) {
outer_graph->SetHasBoundsChecks(true);
}
if (HasLoops()) {
outer_graph->SetHasLoops(true);
}
if (HasIrreducibleLoops()) {
outer_graph->SetHasIrreducibleLoops(true);
}
if (HasTryCatch()) {
outer_graph->SetHasTryCatch(true);
}
if (HasSIMD()) {
outer_graph->SetHasSIMD(true);
}
HInstruction* return_value = nullptr;
if (GetBlocks().size() == 3) {
// Inliner already made sure we don't inline methods that always throw.
DCHECK(!GetBlocks()[1]->GetLastInstruction()->IsThrow());
// Simple case of an entry block, a body block, and an exit block.
// Put the body block's instruction into `invoke`'s block.
HBasicBlock* body = GetBlocks()[1];
DCHECK(GetBlocks()[0]->IsEntryBlock());
DCHECK(GetBlocks()[2]->IsExitBlock());
DCHECK(!body->IsExitBlock());
DCHECK(!body->IsInLoop());
HInstruction* last = body->GetLastInstruction();
// Note that we add instructions before the invoke only to simplify polymorphic inlining.
invoke->GetBlock()->instructions_.AddBefore(invoke, body->GetInstructions());
body->GetInstructions().SetBlockOfInstructions(invoke->GetBlock());
// Replace the invoke with the return value of the inlined graph.
if (last->IsReturn()) {
return_value = last->InputAt(0);
} else {
DCHECK(last->IsReturnVoid());
}
invoke->GetBlock()->RemoveInstruction(last);
} else {
// Need to inline multiple blocks. We split `invoke`'s block
// into two blocks, merge the first block of the inlined graph into
// the first half, and replace the exit block of the inlined graph
// with the second half.
ArenaAllocator* allocator = outer_graph->GetAllocator();
HBasicBlock* at = invoke->GetBlock();