Move Hydrogen and Lithium to src/crankshaft/

src/hydrogen-uint32-analysis.cc

-// Copyright 2013 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "src/hydrogen-uint32-analysis.h"
-
-namespace v8 {
-namespace internal {
-
-
-static bool IsUnsignedLoad(HLoadKeyed* instr) {
-  switch (instr->elements_kind()) {
-    case UINT8_ELEMENTS:
-    case UINT16_ELEMENTS:
-    case UINT32_ELEMENTS:
-    case UINT8_CLAMPED_ELEMENTS:
-      return true;
-    default:
-      return false;
-  }
-}
-
-
-static bool IsUint32Operation(HValue* instr) {
-  return instr->IsShr() ||
-      (instr->IsLoadKeyed() && IsUnsignedLoad(HLoadKeyed::cast(instr))) ||
-      (instr->IsInteger32Constant() && instr->GetInteger32Constant() >= 0);
-}
-
-
-bool HUint32AnalysisPhase::IsSafeUint32Use(HValue* val, HValue* use) {
-  // Operations that operate on bits are safe.
-  if (use->IsBitwise() || use->IsShl() || use->IsSar() || use->IsShr()) {
-    return true;
-  } else if (use->IsSimulate() || use->IsArgumentsObject()) {
-    // Deoptimization has special support for uint32.
-    return true;
-  } else if (use->IsChange()) {
-    // Conversions have special support for uint32.
-    // This DCHECK guards that the conversion in question is actually
-    // implemented. Do not extend the whitelist without adding
-    // support to LChunkBuilder::DoChange().
-    DCHECK(HChange::cast(use)->to().IsDouble() ||
-           HChange::cast(use)->to().IsSmi() ||
-           HChange::cast(use)->to().IsTagged());
-    return true;
-  } else if (use->IsStoreKeyed()) {
-    HStoreKeyed* store = HStoreKeyed::cast(use);
-    if (store->is_fixed_typed_array()) {
-      // Storing a value into an external integer array is a bit level
-      // operation.
-      if (store->value() == val) {
-        // Clamping or a conversion to double should have beed inserted.
-        DCHECK(store->elements_kind() != UINT8_CLAMPED_ELEMENTS);
-        DCHECK(store->elements_kind() != FLOAT32_ELEMENTS);
-        DCHECK(store->elements_kind() != FLOAT64_ELEMENTS);
-        return true;
-      }
-    }
-  } else if (use->IsCompareNumericAndBranch()) {
-    HCompareNumericAndBranch* c = HCompareNumericAndBranch::cast(use);
-    return IsUint32Operation(c->left()) && IsUint32Operation(c->right());
-  }
-
-  return false;
-}
-
-
-// Iterate over all uses and verify that they are uint32 safe: either don't
-// distinguish between int32 and uint32 due to their bitwise nature or
-// have special support for uint32 values.
-// Encountered phis are optimistically treated as safe uint32 uses,
-// marked with kUint32 flag and collected in the phis_ list. A separate
-// pass will be performed later by UnmarkUnsafePhis to clear kUint32 from
-// phis that are not actually uint32-safe (it requires fix point iteration).
-bool HUint32AnalysisPhase::Uint32UsesAreSafe(HValue* uint32val) {
-  bool collect_phi_uses = false;
-  for (HUseIterator it(uint32val->uses()); !it.Done(); it.Advance()) {
-    HValue* use = it.value();
-
-    if (use->IsPhi()) {
-      if (!use->CheckFlag(HInstruction::kUint32)) {
-        // There is a phi use of this value from a phi that is not yet
-        // collected in phis_ array. Separate pass is required.
-        collect_phi_uses = true;
-      }
-
-      // Optimistically treat phis as uint32 safe.
-      continue;
-    }
-
-    if (!IsSafeUint32Use(uint32val, use)) {
-      return false;
-    }
-  }
-
-  if (collect_phi_uses) {
-    for (HUseIterator it(uint32val->uses()); !it.Done(); it.Advance()) {
-      HValue* use = it.value();
-
-      // There is a phi use of this value from a phi that is not yet
-      // collected in phis_ array. Separate pass is required.
-      if (use->IsPhi() && !use->CheckFlag(HInstruction::kUint32)) {
-        use->SetFlag(HInstruction::kUint32);
-        phis_.Add(HPhi::cast(use), zone());
-      }
-    }
-  }
-
-  return true;
-}
-
-
-// Check if all operands to the given phi are marked with kUint32 flag.
-bool HUint32AnalysisPhase::CheckPhiOperands(HPhi* phi) {
-  if (!phi->CheckFlag(HInstruction::kUint32)) {
-    // This phi is not uint32 safe. No need to check operands.
-    return false;
-  }
-
-  for (int j = 0; j < phi->OperandCount(); j++) {
-    HValue* operand = phi->OperandAt(j);
-    if (!operand->CheckFlag(HInstruction::kUint32)) {
-      // Lazily mark constants that fit into uint32 range with kUint32 flag.
-      if (operand->IsInteger32Constant() &&
-          operand->GetInteger32Constant() >= 0) {
-        operand->SetFlag(HInstruction::kUint32);
-        continue;
-      }
-
-      // This phi is not safe, some operands are not uint32 values.
-      return false;
-    }
-  }
-
-  return true;
-}
-
-
-// Remove kUint32 flag from the phi itself and its operands. If any operand
-// was a phi marked with kUint32 place it into a worklist for
-// transitive clearing of kUint32 flag.
-void HUint32AnalysisPhase::UnmarkPhi(HPhi* phi, ZoneList<HPhi*>* worklist) {
-  phi->ClearFlag(HInstruction::kUint32);
-  for (int j = 0; j < phi->OperandCount(); j++) {
-    HValue* operand = phi->OperandAt(j);
-    if (operand->CheckFlag(HInstruction::kUint32)) {
-      operand->ClearFlag(HInstruction::kUint32);
-      if (operand->IsPhi()) {
-        worklist->Add(HPhi::cast(operand), zone());
-      }
-    }
-  }
-}
-
-
-void HUint32AnalysisPhase::UnmarkUnsafePhis() {
-  // No phis were collected. Nothing to do.
-  if (phis_.length() == 0) return;
-
-  // Worklist used to transitively clear kUint32 from phis that
-  // are used as arguments to other phis.
-  ZoneList<HPhi*> worklist(phis_.length(), zone());
-
-  // Phi can be used as a uint32 value if and only if
-  // all its operands are uint32 values and all its
-  // uses are uint32 safe.
-
-  // Iterate over collected phis and unmark those that
-  // are unsafe. When unmarking phi unmark its operands
-  // and add it to the worklist if it is a phi as well.
-  // Phis that are still marked as safe are shifted down
-  // so that all safe phis form a prefix of the phis_ array.
-  int phi_count = 0;
-  for (int i = 0; i < phis_.length(); i++) {
-    HPhi* phi = phis_[i];
-
-    if (CheckPhiOperands(phi) && Uint32UsesAreSafe(phi)) {
-      phis_[phi_count++] = phi;
-    } else {
-      UnmarkPhi(phi, &worklist);
-    }
-  }
-
-  // Now phis array contains only those phis that have safe
-  // non-phi uses. Start transitively clearing kUint32 flag
-  // from phi operands of discovered non-safe phis until
-  // only safe phis are left.
-  while (!worklist.is_empty())  {
-    while (!worklist.is_empty()) {
-      HPhi* phi = worklist.RemoveLast();
-      UnmarkPhi(phi, &worklist);
-    }
-
-    // Check if any operands to safe phis were unmarked
-    // turning a safe phi into unsafe. The same value
-    // can flow into several phis.
-    int new_phi_count = 0;
-    for (int i = 0; i < phi_count; i++) {
-      HPhi* phi = phis_[i];
-
-      if (CheckPhiOperands(phi)) {
-        phis_[new_phi_count++] = phi;
-      } else {
-        UnmarkPhi(phi, &worklist);
-      }
-    }
-    phi_count = new_phi_count;
-  }
-}
-
-
-void HUint32AnalysisPhase::Run() {
-  if (!graph()->has_uint32_instructions()) return;
-
-  ZoneList<HInstruction*>* uint32_instructions = graph()->uint32_instructions();
-  for (int i = 0; i < uint32_instructions->length(); ++i) {
-    // Analyze instruction and mark it with kUint32 if all
-    // its uses are uint32 safe.
-    HInstruction* current = uint32_instructions->at(i);
-    if (current->IsLinked() &&
-        current->representation().IsInteger32() &&
-        Uint32UsesAreSafe(current)) {
-      current->SetFlag(HInstruction::kUint32);
-    }
-  }
-
-  // Some phis might have been optimistically marked with kUint32 flag.
-  // Remove this flag from those phis that are unsafe and propagate
-  // this information transitively potentially clearing kUint32 flag
-  // from some non-phi operations that are used as operands to unsafe phis.
-  UnmarkUnsafePhis();
-}
-
-
-}  // namespace internal
-}  // namespace v8