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      1 // Copyright 2014 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef V8_COMPILER_NODE_MATCHERS_H_
      6 #define V8_COMPILER_NODE_MATCHERS_H_
      7 
      8 #include <cmath>
      9 
     10 // TODO(turbofan): Move ExternalReference out of assembler.h
     11 #include "src/assembler.h"
     12 #include "src/compiler/node.h"
     13 #include "src/compiler/operator.h"
     14 
     15 namespace v8 {
     16 namespace internal {
     17 namespace compiler {
     18 
     19 // A pattern matcher for nodes.
     20 struct NodeMatcher {
     21   explicit NodeMatcher(Node* node) : node_(node) {}
     22 
     23   Node* node() const { return node_; }
     24   const Operator* op() const { return node()->op(); }
     25   IrOpcode::Value opcode() const { return node()->opcode(); }
     26 
     27   bool HasProperty(Operator::Property property) const {
     28     return op()->HasProperty(property);
     29   }
     30   Node* InputAt(int index) const { return node()->InputAt(index); }
     31 
     32   bool Equals(const Node* node) const { return node_ == node; }
     33 
     34   bool IsComparison() const;
     35 
     36 #define DEFINE_IS_OPCODE(Opcode) \
     37   bool Is##Opcode() const { return opcode() == IrOpcode::k##Opcode; }
     38   ALL_OP_LIST(DEFINE_IS_OPCODE)
     39 #undef DEFINE_IS_OPCODE
     40 
     41  private:
     42   Node* node_;
     43 };
     44 
     45 
     46 // A pattern matcher for abitrary value constants.
     47 template <typename T, IrOpcode::Value kOpcode>
     48 struct ValueMatcher : public NodeMatcher {
     49   typedef T ValueType;
     50 
     51   explicit ValueMatcher(Node* node)
     52       : NodeMatcher(node), value_(), has_value_(opcode() == kOpcode) {
     53     if (has_value_) {
     54       value_ = OpParameter<T>(node);
     55     }
     56   }
     57 
     58   bool HasValue() const { return has_value_; }
     59   const T& Value() const {
     60     DCHECK(HasValue());
     61     return value_;
     62   }
     63 
     64  private:
     65   T value_;
     66   bool has_value_;
     67 };
     68 
     69 
     70 template <>
     71 inline ValueMatcher<uint32_t, IrOpcode::kInt32Constant>::ValueMatcher(
     72     Node* node)
     73     : NodeMatcher(node),
     74       value_(),
     75       has_value_(opcode() == IrOpcode::kInt32Constant) {
     76   if (has_value_) {
     77     value_ = static_cast<uint32_t>(OpParameter<int32_t>(node));
     78   }
     79 }
     80 
     81 
     82 template <>
     83 inline ValueMatcher<int64_t, IrOpcode::kInt64Constant>::ValueMatcher(Node* node)
     84     : NodeMatcher(node), value_(), has_value_(false) {
     85   if (opcode() == IrOpcode::kInt32Constant) {
     86     value_ = OpParameter<int32_t>(node);
     87     has_value_ = true;
     88   } else if (opcode() == IrOpcode::kInt64Constant) {
     89     value_ = OpParameter<int64_t>(node);
     90     has_value_ = true;
     91   }
     92 }
     93 
     94 
     95 template <>
     96 inline ValueMatcher<uint64_t, IrOpcode::kInt64Constant>::ValueMatcher(
     97     Node* node)
     98     : NodeMatcher(node), value_(), has_value_(false) {
     99   if (opcode() == IrOpcode::kInt32Constant) {
    100     value_ = static_cast<uint32_t>(OpParameter<int32_t>(node));
    101     has_value_ = true;
    102   } else if (opcode() == IrOpcode::kInt64Constant) {
    103     value_ = static_cast<uint64_t>(OpParameter<int64_t>(node));
    104     has_value_ = true;
    105   }
    106 }
    107 
    108 
    109 // A pattern matcher for integer constants.
    110 template <typename T, IrOpcode::Value kOpcode>
    111 struct IntMatcher final : public ValueMatcher<T, kOpcode> {
    112   explicit IntMatcher(Node* node) : ValueMatcher<T, kOpcode>(node) {}
    113 
    114   bool Is(const T& value) const {
    115     return this->HasValue() && this->Value() == value;
    116   }
    117   bool IsInRange(const T& low, const T& high) const {
    118     return this->HasValue() && low <= this->Value() && this->Value() <= high;
    119   }
    120   bool IsMultipleOf(T n) const {
    121     return this->HasValue() && (this->Value() % n) == 0;
    122   }
    123   bool IsPowerOf2() const {
    124     return this->HasValue() && this->Value() > 0 &&
    125            (this->Value() & (this->Value() - 1)) == 0;
    126   }
    127   bool IsNegativePowerOf2() const {
    128     return this->HasValue() && this->Value() < 0 &&
    129            (-this->Value() & (-this->Value() - 1)) == 0;
    130   }
    131 };
    132 
    133 typedef IntMatcher<int32_t, IrOpcode::kInt32Constant> Int32Matcher;
    134 typedef IntMatcher<uint32_t, IrOpcode::kInt32Constant> Uint32Matcher;
    135 typedef IntMatcher<int64_t, IrOpcode::kInt64Constant> Int64Matcher;
    136 typedef IntMatcher<uint64_t, IrOpcode::kInt64Constant> Uint64Matcher;
    137 #if V8_HOST_ARCH_32_BIT
    138 typedef Int32Matcher IntPtrMatcher;
    139 typedef Uint32Matcher UintPtrMatcher;
    140 #else
    141 typedef Int64Matcher IntPtrMatcher;
    142 typedef Uint64Matcher UintPtrMatcher;
    143 #endif
    144 
    145 
    146 // A pattern matcher for floating point constants.
    147 template <typename T, IrOpcode::Value kOpcode>
    148 struct FloatMatcher final : public ValueMatcher<T, kOpcode> {
    149   explicit FloatMatcher(Node* node) : ValueMatcher<T, kOpcode>(node) {}
    150 
    151   bool Is(const T& value) const {
    152     return this->HasValue() && this->Value() == value;
    153   }
    154   bool IsInRange(const T& low, const T& high) const {
    155     return this->HasValue() && low <= this->Value() && this->Value() <= high;
    156   }
    157   bool IsMinusZero() const {
    158     return this->Is(0.0) && std::signbit(this->Value());
    159   }
    160   bool IsNaN() const { return this->HasValue() && std::isnan(this->Value()); }
    161   bool IsZero() const { return this->Is(0.0) && !std::signbit(this->Value()); }
    162 };
    163 
    164 typedef FloatMatcher<float, IrOpcode::kFloat32Constant> Float32Matcher;
    165 typedef FloatMatcher<double, IrOpcode::kFloat64Constant> Float64Matcher;
    166 typedef FloatMatcher<double, IrOpcode::kNumberConstant> NumberMatcher;
    167 
    168 
    169 // A pattern matcher for heap object constants.
    170 struct HeapObjectMatcher final
    171     : public ValueMatcher<Handle<HeapObject>, IrOpcode::kHeapConstant> {
    172   explicit HeapObjectMatcher(Node* node)
    173       : ValueMatcher<Handle<HeapObject>, IrOpcode::kHeapConstant>(node) {}
    174 };
    175 
    176 
    177 // A pattern matcher for external reference constants.
    178 struct ExternalReferenceMatcher final
    179     : public ValueMatcher<ExternalReference, IrOpcode::kExternalConstant> {
    180   explicit ExternalReferenceMatcher(Node* node)
    181       : ValueMatcher<ExternalReference, IrOpcode::kExternalConstant>(node) {}
    182   bool Is(const ExternalReference& value) const {
    183     return this->HasValue() && this->Value() == value;
    184   }
    185 };
    186 
    187 
    188 // For shorter pattern matching code, this struct matches the inputs to
    189 // machine-level load operations.
    190 template <typename Object>
    191 struct LoadMatcher : public NodeMatcher {
    192   explicit LoadMatcher(Node* node)
    193       : NodeMatcher(node), object_(InputAt(0)), index_(InputAt(1)) {}
    194 
    195   typedef Object ObjectMatcher;
    196 
    197   Object const& object() const { return object_; }
    198   IntPtrMatcher const& index() const { return index_; }
    199 
    200  private:
    201   Object const object_;
    202   IntPtrMatcher const index_;
    203 };
    204 
    205 
    206 // For shorter pattern matching code, this struct matches both the left and
    207 // right hand sides of a binary operation and can put constants on the right
    208 // if they appear on the left hand side of a commutative operation.
    209 template <typename Left, typename Right>
    210 struct BinopMatcher : public NodeMatcher {
    211   explicit BinopMatcher(Node* node)
    212       : NodeMatcher(node), left_(InputAt(0)), right_(InputAt(1)) {
    213     if (HasProperty(Operator::kCommutative)) PutConstantOnRight();
    214   }
    215   BinopMatcher(Node* node, bool allow_input_swap)
    216       : NodeMatcher(node), left_(InputAt(0)), right_(InputAt(1)) {
    217     if (allow_input_swap) PutConstantOnRight();
    218   }
    219 
    220   typedef Left LeftMatcher;
    221   typedef Right RightMatcher;
    222 
    223   const Left& left() const { return left_; }
    224   const Right& right() const { return right_; }
    225 
    226   bool IsFoldable() const { return left().HasValue() && right().HasValue(); }
    227   bool LeftEqualsRight() const { return left().node() == right().node(); }
    228 
    229  protected:
    230   void SwapInputs() {
    231     std::swap(left_, right_);
    232     node()->ReplaceInput(0, left().node());
    233     node()->ReplaceInput(1, right().node());
    234   }
    235 
    236  private:
    237   void PutConstantOnRight() {
    238     if (left().HasValue() && !right().HasValue()) {
    239       SwapInputs();
    240     }
    241   }
    242 
    243   Left left_;
    244   Right right_;
    245 };
    246 
    247 typedef BinopMatcher<Int32Matcher, Int32Matcher> Int32BinopMatcher;
    248 typedef BinopMatcher<Uint32Matcher, Uint32Matcher> Uint32BinopMatcher;
    249 typedef BinopMatcher<Int64Matcher, Int64Matcher> Int64BinopMatcher;
    250 typedef BinopMatcher<Uint64Matcher, Uint64Matcher> Uint64BinopMatcher;
    251 typedef BinopMatcher<IntPtrMatcher, IntPtrMatcher> IntPtrBinopMatcher;
    252 typedef BinopMatcher<UintPtrMatcher, UintPtrMatcher> UintPtrBinopMatcher;
    253 typedef BinopMatcher<Float32Matcher, Float32Matcher> Float32BinopMatcher;
    254 typedef BinopMatcher<Float64Matcher, Float64Matcher> Float64BinopMatcher;
    255 typedef BinopMatcher<NumberMatcher, NumberMatcher> NumberBinopMatcher;
    256 typedef BinopMatcher<HeapObjectMatcher, HeapObjectMatcher>
    257     HeapObjectBinopMatcher;
    258 
    259 template <class BinopMatcher, IrOpcode::Value kMulOpcode,
    260           IrOpcode::Value kShiftOpcode>
    261 struct ScaleMatcher {
    262   explicit ScaleMatcher(Node* node, bool allow_power_of_two_plus_one = false)
    263       : scale_(-1), power_of_two_plus_one_(false) {
    264     if (node->InputCount() < 2) return;
    265     BinopMatcher m(node);
    266     if (node->opcode() == kShiftOpcode) {
    267       if (m.right().HasValue()) {
    268         typename BinopMatcher::RightMatcher::ValueType value =
    269             m.right().Value();
    270         if (value >= 0 && value <= 3) {
    271           scale_ = static_cast<int>(value);
    272         }
    273       }
    274     } else if (node->opcode() == kMulOpcode) {
    275       if (m.right().HasValue()) {
    276         typename BinopMatcher::RightMatcher::ValueType value =
    277             m.right().Value();
    278         if (value == 1) {
    279           scale_ = 0;
    280         } else if (value == 2) {
    281           scale_ = 1;
    282         } else if (value == 4) {
    283           scale_ = 2;
    284         } else if (value == 8) {
    285           scale_ = 3;
    286         } else if (allow_power_of_two_plus_one) {
    287           if (value == 3) {
    288             scale_ = 1;
    289             power_of_two_plus_one_ = true;
    290           } else if (value == 5) {
    291             scale_ = 2;
    292             power_of_two_plus_one_ = true;
    293           } else if (value == 9) {
    294             scale_ = 3;
    295             power_of_two_plus_one_ = true;
    296           }
    297         }
    298       }
    299     }
    300   }
    301 
    302   bool matches() const { return scale_ != -1; }
    303   int scale() const { return scale_; }
    304   bool power_of_two_plus_one() const { return power_of_two_plus_one_; }
    305 
    306  private:
    307   int scale_;
    308   bool power_of_two_plus_one_;
    309 };
    310 
    311 typedef ScaleMatcher<Int32BinopMatcher, IrOpcode::kInt32Mul,
    312                      IrOpcode::kWord32Shl> Int32ScaleMatcher;
    313 typedef ScaleMatcher<Int64BinopMatcher, IrOpcode::kInt64Mul,
    314                      IrOpcode::kWord64Shl> Int64ScaleMatcher;
    315 
    316 
    317 template <class BinopMatcher, IrOpcode::Value kAddOpcode,
    318           IrOpcode::Value kMulOpcode, IrOpcode::Value kShiftOpcode>
    319 struct AddMatcher : public BinopMatcher {
    320   static const IrOpcode::Value kOpcode = kAddOpcode;
    321   typedef ScaleMatcher<BinopMatcher, kMulOpcode, kShiftOpcode> Matcher;
    322 
    323   AddMatcher(Node* node, bool allow_input_swap)
    324       : BinopMatcher(node, allow_input_swap),
    325         scale_(-1),
    326         power_of_two_plus_one_(false) {
    327     Initialize(node, allow_input_swap);
    328   }
    329   explicit AddMatcher(Node* node)
    330       : BinopMatcher(node, node->op()->HasProperty(Operator::kCommutative)),
    331         scale_(-1),
    332         power_of_two_plus_one_(false) {
    333     Initialize(node, node->op()->HasProperty(Operator::kCommutative));
    334   }
    335 
    336   bool HasIndexInput() const { return scale_ != -1; }
    337   Node* IndexInput() const {
    338     DCHECK(HasIndexInput());
    339     return this->left().node()->InputAt(0);
    340   }
    341   int scale() const {
    342     DCHECK(HasIndexInput());
    343     return scale_;
    344   }
    345   bool power_of_two_plus_one() const { return power_of_two_plus_one_; }
    346 
    347  private:
    348   void Initialize(Node* node, bool allow_input_swap) {
    349     Matcher left_matcher(this->left().node(), true);
    350     if (left_matcher.matches()) {
    351       scale_ = left_matcher.scale();
    352       power_of_two_plus_one_ = left_matcher.power_of_two_plus_one();
    353       return;
    354     }
    355 
    356     if (!allow_input_swap) {
    357       return;
    358     }
    359 
    360     Matcher right_matcher(this->right().node(), true);
    361     if (right_matcher.matches()) {
    362       scale_ = right_matcher.scale();
    363       power_of_two_plus_one_ = right_matcher.power_of_two_plus_one();
    364       this->SwapInputs();
    365       return;
    366     }
    367 
    368     if (this->right().opcode() == kAddOpcode &&
    369         this->left().opcode() != kAddOpcode) {
    370       this->SwapInputs();
    371     }
    372   }
    373 
    374   int scale_;
    375   bool power_of_two_plus_one_;
    376 };
    377 
    378 typedef AddMatcher<Int32BinopMatcher, IrOpcode::kInt32Add, IrOpcode::kInt32Mul,
    379                    IrOpcode::kWord32Shl> Int32AddMatcher;
    380 typedef AddMatcher<Int64BinopMatcher, IrOpcode::kInt64Add, IrOpcode::kInt64Mul,
    381                    IrOpcode::kWord64Shl> Int64AddMatcher;
    382 
    383 
    384 template <class AddMatcher>
    385 struct BaseWithIndexAndDisplacementMatcher {
    386   BaseWithIndexAndDisplacementMatcher(Node* node, bool allow_input_swap)
    387       : matches_(false),
    388         index_(nullptr),
    389         scale_(0),
    390         base_(nullptr),
    391         displacement_(nullptr) {
    392     Initialize(node, allow_input_swap);
    393   }
    394 
    395   explicit BaseWithIndexAndDisplacementMatcher(Node* node)
    396       : matches_(false),
    397         index_(nullptr),
    398         scale_(0),
    399         base_(nullptr),
    400         displacement_(nullptr) {
    401     Initialize(node, node->op()->HasProperty(Operator::kCommutative));
    402   }
    403 
    404   bool matches() const { return matches_; }
    405   Node* index() const { return index_; }
    406   int scale() const { return scale_; }
    407   Node* base() const { return base_; }
    408   Node* displacement() const { return displacement_; }
    409 
    410  private:
    411   bool matches_;
    412   Node* index_;
    413   int scale_;
    414   Node* base_;
    415   Node* displacement_;
    416 
    417   void Initialize(Node* node, bool allow_input_swap) {
    418     // The BaseWithIndexAndDisplacementMatcher canonicalizes the order of
    419     // displacements and scale factors that are used as inputs, so instead of
    420     // enumerating all possible patterns by brute force, checking for node
    421     // clusters using the following templates in the following order suffices to
    422     // find all of the interesting cases (S = index * scale, B = base input, D =
    423     // displacement input):
    424     // (S + (B + D))
    425     // (S + (B + B))
    426     // (S + D)
    427     // (S + B)
    428     // ((S + D) + B)
    429     // ((S + B) + D)
    430     // ((B + D) + B)
    431     // ((B + B) + D)
    432     // (B + D)
    433     // (B + B)
    434     if (node->InputCount() < 2) return;
    435     AddMatcher m(node, allow_input_swap);
    436     Node* left = m.left().node();
    437     Node* right = m.right().node();
    438     Node* displacement = nullptr;
    439     Node* base = nullptr;
    440     Node* index = nullptr;
    441     Node* scale_expression = nullptr;
    442     bool power_of_two_plus_one = false;
    443     int scale = 0;
    444     if (m.HasIndexInput() && left->OwnedBy(node)) {
    445       index = m.IndexInput();
    446       scale = m.scale();
    447       scale_expression = left;
    448       power_of_two_plus_one = m.power_of_two_plus_one();
    449       if (right->opcode() == AddMatcher::kOpcode && right->OwnedBy(node)) {
    450         AddMatcher right_matcher(right);
    451         if (right_matcher.right().HasValue()) {
    452           // (S + (B + D))
    453           base = right_matcher.left().node();
    454           displacement = right_matcher.right().node();
    455         } else {
    456           // (S + (B + B))
    457           base = right;
    458         }
    459       } else if (m.right().HasValue()) {
    460         // (S + D)
    461         displacement = right;
    462       } else {
    463         // (S + B)
    464         base = right;
    465       }
    466     } else {
    467       if (left->opcode() == AddMatcher::kOpcode && left->OwnedBy(node)) {
    468         AddMatcher left_matcher(left);
    469         Node* left_left = left_matcher.left().node();
    470         Node* left_right = left_matcher.right().node();
    471         if (left_matcher.HasIndexInput() && left_left->OwnedBy(left)) {
    472           if (left_matcher.right().HasValue()) {
    473             // ((S + D) + B)
    474             index = left_matcher.IndexInput();
    475             scale = left_matcher.scale();
    476             scale_expression = left_left;
    477             power_of_two_plus_one = left_matcher.power_of_two_plus_one();
    478             displacement = left_right;
    479             base = right;
    480           } else if (m.right().HasValue()) {
    481             // ((S + B) + D)
    482             index = left_matcher.IndexInput();
    483             scale = left_matcher.scale();
    484             scale_expression = left_left;
    485             power_of_two_plus_one = left_matcher.power_of_two_plus_one();
    486             base = left_right;
    487             displacement = right;
    488           } else {
    489             // (B + B)
    490             index = left;
    491             base = right;
    492           }
    493         } else {
    494           if (left_matcher.right().HasValue()) {
    495             // ((B + D) + B)
    496             index = left_left;
    497             displacement = left_right;
    498             base = right;
    499           } else if (m.right().HasValue()) {
    500             // ((B + B) + D)
    501             index = left_left;
    502             base = left_right;
    503             displacement = right;
    504           } else {
    505             // (B + B)
    506             index = left;
    507             base = right;
    508           }
    509         }
    510       } else {
    511         if (m.right().HasValue()) {
    512           // (B + D)
    513           base = left;
    514           displacement = right;
    515         } else {
    516           // (B + B)
    517           base = left;
    518           index = right;
    519         }
    520       }
    521     }
    522     int64_t value = 0;
    523     if (displacement != nullptr) {
    524       switch (displacement->opcode()) {
    525         case IrOpcode::kInt32Constant: {
    526           value = OpParameter<int32_t>(displacement);
    527           break;
    528         }
    529         case IrOpcode::kInt64Constant: {
    530           value = OpParameter<int64_t>(displacement);
    531           break;
    532         }
    533         default:
    534           UNREACHABLE();
    535           break;
    536       }
    537       if (value == 0) {
    538         displacement = nullptr;
    539       }
    540     }
    541     if (power_of_two_plus_one) {
    542       if (base != nullptr) {
    543         // If the scale requires explicitly using the index as the base, but a
    544         // base is already part of the match, then the (1 << N + 1) scale factor
    545         // can't be folded into the match and the entire index * scale
    546         // calculation must be computed separately.
    547         index = scale_expression;
    548         scale = 0;
    549       } else {
    550         base = index;
    551       }
    552     }
    553     base_ = base;
    554     displacement_ = displacement;
    555     index_ = index;
    556     scale_ = scale;
    557     matches_ = true;
    558   }
    559 };
    560 
    561 typedef BaseWithIndexAndDisplacementMatcher<Int32AddMatcher>
    562     BaseWithIndexAndDisplacement32Matcher;
    563 typedef BaseWithIndexAndDisplacementMatcher<Int64AddMatcher>
    564     BaseWithIndexAndDisplacement64Matcher;
    565 
    566 struct BranchMatcher : public NodeMatcher {
    567   explicit BranchMatcher(Node* branch);
    568 
    569   bool Matched() const { return if_true_ && if_false_; }
    570 
    571   Node* Branch() const { return node(); }
    572   Node* IfTrue() const { return if_true_; }
    573   Node* IfFalse() const { return if_false_; }
    574 
    575  private:
    576   Node* if_true_;
    577   Node* if_false_;
    578 };
    579 
    580 
    581 struct DiamondMatcher : public NodeMatcher {
    582   explicit DiamondMatcher(Node* merge);
    583 
    584   bool Matched() const { return branch_; }
    585   bool IfProjectionsAreOwned() const {
    586     return if_true_->OwnedBy(node()) && if_false_->OwnedBy(node());
    587   }
    588 
    589   Node* Branch() const { return branch_; }
    590   Node* IfTrue() const { return if_true_; }
    591   Node* IfFalse() const { return if_false_; }
    592   Node* Merge() const { return node(); }
    593 
    594   Node* TrueInputOf(Node* phi) const {
    595     DCHECK(IrOpcode::IsPhiOpcode(phi->opcode()));
    596     DCHECK_EQ(3, phi->InputCount());
    597     DCHECK_EQ(Merge(), phi->InputAt(2));
    598     return phi->InputAt(if_true_ == Merge()->InputAt(0) ? 0 : 1);
    599   }
    600 
    601   Node* FalseInputOf(Node* phi) const {
    602     DCHECK(IrOpcode::IsPhiOpcode(phi->opcode()));
    603     DCHECK_EQ(3, phi->InputCount());
    604     DCHECK_EQ(Merge(), phi->InputAt(2));
    605     return phi->InputAt(if_true_ == Merge()->InputAt(0) ? 1 : 0);
    606   }
    607 
    608  private:
    609   Node* branch_;
    610   Node* if_true_;
    611   Node* if_false_;
    612 };
    613 
    614 }  // namespace compiler
    615 }  // namespace internal
    616 }  // namespace v8
    617 
    618 #endif  // V8_COMPILER_NODE_MATCHERS_H_
    619