Turn UInt32 analysis into a proper HPhase.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/18487003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15441 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-uint32-analysis.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "hydrogen-uint32-analysis.h"
+
+namespace v8 {
+namespace internal {
+
+
+bool HUint32AnalysisPhase::IsSafeUint32Use(HValue* val, HValue* use) {
+  // Operations that operate on bits are safe.
+  if (use->IsBitwise() ||
+      use->IsShl() ||
+      use->IsSar() ||
+      use->IsShr() ||
+      use->IsBitNot()) {
+    return true;
+  } else if (use->IsChange() || use->IsSimulate()) {
+    // Conversions and deoptimization have special support for unt32.
+    return true;
+  } else if (use->IsStoreKeyed()) {
+    HStoreKeyed* store = HStoreKeyed::cast(use);
+    if (store->is_external()) {
+      // 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.
+        ASSERT(store->elements_kind() != EXTERNAL_PIXEL_ELEMENTS);
+        ASSERT(store->elements_kind() != EXTERNAL_FLOAT_ELEMENTS);
+        ASSERT(store->elements_kind() != EXTERNAL_DOUBLE_ELEMENTS);
+        return true;
+      }
+    }
+  }
+
+  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 (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 v8::internal

src/hydrogen-uint32-analysis.h

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_HYDROGEN_UINT32_ANALYSIS_H_
+#define V8_HYDROGEN_UINT32_ANALYSIS_H_
+
+#include "hydrogen.h"
+
+namespace v8 {
+namespace internal {
+
+
+// Discover instructions that can be marked with kUint32 flag allowing
+// them to produce full range uint32 values.
+class HUint32AnalysisPhase : public HPhase {
+ public:
+  explicit HUint32AnalysisPhase(HGraph* graph)
+      : HPhase("H_Compute safe UInt32 operations", graph), phis_(4, zone()) { }
+
+  void Run();
+
+ private:
+  INLINE(bool IsSafeUint32Use(HValue* val, HValue* use));
+  INLINE(bool Uint32UsesAreSafe(HValue* uint32val));
+  INLINE(bool CheckPhiOperands(HPhi* phi));
+  INLINE(void UnmarkPhi(HPhi* phi, ZoneList<HPhi*>* worklist));
+  INLINE(void UnmarkUnsafePhis());
+
+  ZoneList<HPhi*> phis_;
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_HYDROGEN_UINT32_ANALYSIS_H_

src/hydrogen.cc

@@ -37,6 +37,7 @@
 #include "hydrogen-escape-analysis.h"
 #include "hydrogen-infer-representation.h"
 #include "hydrogen-gvn.h"
+#include "hydrogen-uint32-analysis.h"
 #include "lithium-allocator.h"
 #include "parser.h"
 #include "scopeinfo.h"
@@ -3078,228 +3079,6 @@ void HGraph::MarkDeoptimizeOnUndefined() {
 }
 
 
-// Discover instructions that can be marked with kUint32 flag allowing
-// them to produce full range uint32 values.
-class Uint32Analysis BASE_EMBEDDED {
- public:
-  explicit Uint32Analysis(Zone* zone) : zone_(zone), phis_(4, zone) { }
-
-  void Analyze(HInstruction* current);
-
-  void UnmarkUnsafePhis();
-
- private:
-  bool IsSafeUint32Use(HValue* val, HValue* use);
-  bool Uint32UsesAreSafe(HValue* uint32val);
-  bool CheckPhiOperands(HPhi* phi);
-  void UnmarkPhi(HPhi* phi, ZoneList<HPhi*>* worklist);
-
-  Zone* zone_;
-  ZoneList<HPhi*> phis_;
-};
-
-
-bool Uint32Analysis::IsSafeUint32Use(HValue* val, HValue* use) {
-  // Operations that operatate on bits are safe.
-  if (use->IsBitwise() ||
-      use->IsShl() ||
-      use->IsSar() ||
-      use->IsShr() ||
-      use->IsBitNot()) {
-    return true;
-  } else if (use->IsChange() || use->IsSimulate()) {
-    // Conversions and deoptimization have special support for unt32.
-    return true;
-  } else if (use->IsStoreKeyed()) {
-    HStoreKeyed* store = HStoreKeyed::cast(use);
-    if (store->is_external()) {
-      // 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.
-        ASSERT(store->elements_kind() != EXTERNAL_PIXEL_ELEMENTS);
-        ASSERT(store->elements_kind() != EXTERNAL_FLOAT_ELEMENTS);
-        ASSERT(store->elements_kind() != EXTERNAL_DOUBLE_ELEMENTS);
-        return true;
-      }
-    }
-  }
-
-  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 optimisitically treated as safe uint32 uses,
-// marked with kUint32 flag and collected in the phis_ list. A separate
-// path will be performed later by UnmarkUnsafePhis to clear kUint32 from
-// phis that are not actually uint32-safe (it requries fix point iteration).
-bool Uint32Analysis::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 phis 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 phis 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;
-}
-
-
-// Analyze instruction and mark it with kUint32 if all its uses are uint32
-// safe.
-void Uint32Analysis::Analyze(HInstruction* current) {
-  if (Uint32UsesAreSafe(current)) current->SetFlag(HInstruction::kUint32);
-}
-
-
-// Check if all operands to the given phi are marked with kUint32 flag.
-bool Uint32Analysis::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)) {
-      // Lazyly 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 Uint32Analysis::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 Uint32Analysis::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 phies until
-  // only safe phies are left.
-  while (!worklist.is_empty())  {
-    while (!worklist.is_empty()) {
-      HPhi* phi = worklist.RemoveLast();
-      UnmarkPhi(phi, &worklist);
-    }
-
-    // Check if any operands to safe phies 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 HGraph::ComputeSafeUint32Operations() {
-  HPhase phase("H_Compute safe UInt32 operations", this);
-  if (uint32_instructions_ == NULL) return;
-
-  Uint32Analysis analysis(zone());
-  for (int i = 0; i < uint32_instructions_->length(); ++i) {
-    HInstruction* current = uint32_instructions_->at(i);
-    if (current->IsLinked() && current->representation().IsInteger32()) {
-      analysis.Analyze(current);
-    }
-  }
-
-  // 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.
-  analysis.UnmarkUnsafePhis();
-}
-
-
 void HGraph::ComputeMinusZeroChecks() {
   HPhase phase("H_Compute minus zero checks", this);
   BitVector visited(GetMaximumValueID(), zone());
@@ -3811,7 +3590,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
   // Must be performed before canonicalization to ensure that Canonicalize
   // will not remove semantically meaningful ToInt32 operations e.g. BIT_OR with
   // zero.
-  if (FLAG_opt_safe_uint32_operations) ComputeSafeUint32Operations();
+  if (FLAG_opt_safe_uint32_operations) Run<HUint32AnalysisPhase>();
 
   if (FLAG_use_canonicalizing) Canonicalize();
 

src/hydrogen.h

@@ -296,7 +296,6 @@ class HGraph: public ZoneObject {
   void InsertRepresentationChanges();
   void MarkDeoptimizeOnUndefined();
   void ComputeMinusZeroChecks();
-  void ComputeSafeUint32Operations();
   bool ProcessArgumentsObject();
   void EliminateRedundantPhis();
   void Canonicalize();
@@ -429,7 +428,18 @@ class HGraph: public ZoneObject {
     return depends_on_empty_array_proto_elements_;
   }
 
+  bool has_uint32_instructions() {
+    ASSERT(uint32_instructions_ == NULL || !uint32_instructions_->is_empty());
+    return uint32_instructions_ != NULL;
+  }
+
+  ZoneList<HInstruction*>* uint32_instructions() {
+    ASSERT(uint32_instructions_ == NULL || !uint32_instructions_->is_empty());
+    return uint32_instructions_;
+  }
+
   void RecordUint32Instruction(HInstruction* instr) {
+    ASSERT(uint32_instructions_ == NULL || !uint32_instructions_->is_empty());
     if (uint32_instructions_ == NULL) {
       uint32_instructions_ = new(zone()) ZoneList<HInstruction*>(4, zone());
     }

tools/gyp/v8.gyp

@@ -337,6 +337,8 @@
         '../../src/hydrogen-gvn.h',
         '../../src/hydrogen-infer-representation.cc',
         '../../src/hydrogen-infer-representation.h',
+        '../../src/hydrogen-uint32-analysis.cc',
+        '../../src/hydrogen-uint32-analysis.h',
         '../../src/ic-inl.h',
         '../../src/ic.cc',
         '../../src/ic.h',