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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 
    257 
    258 template <class BinopMatcher, IrOpcode::Value kMulOpcode,
    259           IrOpcode::Value kShiftOpcode>
    260 struct ScaleMatcher {
    261   explicit ScaleMatcher(Node* node, bool allow_power_of_two_plus_one = false)
    262       : scale_(-1), power_of_two_plus_one_(false) {
    263     if (node->InputCount() < 2) return;
    264     BinopMatcher m(node);
    265     if (node->opcode() == kShiftOpcode) {
    266       if (m.right().HasValue()) {
    267         typename BinopMatcher::RightMatcher::ValueType value =
    268             m.right().Value();
    269         if (value >= 0 && value <= 3) {
    270           scale_ = static_cast<int>(value);
    271         }
    272       }
    273     } else if (node->opcode() == kMulOpcode) {
    274       if (m.right().HasValue()) {
    275         typename BinopMatcher::RightMatcher::ValueType value =
    276             m.right().Value();
    277         if (value == 1) {
    278           scale_ = 0;
    279         } else if (value == 2) {
    280           scale_ = 1;
    281         } else if (value == 4) {
    282           scale_ = 2;
    283         } else if (value == 8) {
    284           scale_ = 3;
    285         } else if (allow_power_of_two_plus_one) {
    286           if (value == 3) {
    287             scale_ = 1;
    288             power_of_two_plus_one_ = true;
    289           } else if (value == 5) {
    290             scale_ = 2;
    291             power_of_two_plus_one_ = true;
    292           } else if (value == 9) {
    293             scale_ = 3;
    294             power_of_two_plus_one_ = true;
    295           }
    296         }
    297       }
    298     }
    299   }
    300 
    301   bool matches() const { return scale_ != -1; }
    302   int scale() const { return scale_; }
    303   bool power_of_two_plus_one() const { return power_of_two_plus_one_; }
    304 
    305  private:
    306   int scale_;
    307   bool power_of_two_plus_one_;
    308 };
    309 
    310 typedef ScaleMatcher<Int32BinopMatcher, IrOpcode::kInt32Mul,
    311                      IrOpcode::kWord32Shl> Int32ScaleMatcher;
    312 typedef ScaleMatcher<Int64BinopMatcher, IrOpcode::kInt64Mul,
    313                      IrOpcode::kWord64Shl> Int64ScaleMatcher;
    314 
    315 
    316 template <class BinopMatcher, IrOpcode::Value kAddOpcode,
    317           IrOpcode::Value kMulOpcode, IrOpcode::Value kShiftOpcode>
    318 struct AddMatcher : public BinopMatcher {
    319   static const IrOpcode::Value kOpcode = kAddOpcode;
    320   typedef ScaleMatcher<BinopMatcher, kMulOpcode, kShiftOpcode> Matcher;
    321 
    322   AddMatcher(Node* node, bool allow_input_swap)
    323       : BinopMatcher(node, allow_input_swap),
    324         scale_(-1),
    325         power_of_two_plus_one_(false) {
    326     Initialize(node, allow_input_swap);
    327   }
    328   explicit AddMatcher(Node* node)
    329       : BinopMatcher(node, node->op()->HasProperty(Operator::kCommutative)),
    330         scale_(-1),
    331         power_of_two_plus_one_(false) {
    332     Initialize(node, node->op()->HasProperty(Operator::kCommutative));
    333   }
    334 
    335   bool HasIndexInput() const { return scale_ != -1; }
    336   Node* IndexInput() const {
    337     DCHECK(HasIndexInput());
    338     return this->left().node()->InputAt(0);
    339   }
    340   int scale() const {
    341     DCHECK(HasIndexInput());
    342     return scale_;
    343   }
    344   bool power_of_two_plus_one() const { return power_of_two_plus_one_; }
    345 
    346  private:
    347   void Initialize(Node* node, bool allow_input_swap) {
    348     Matcher left_matcher(this->left().node(), true);
    349     if (left_matcher.matches()) {
    350       scale_ = left_matcher.scale();
    351       power_of_two_plus_one_ = left_matcher.power_of_two_plus_one();
    352       return;
    353     }
    354 
    355     if (!allow_input_swap) {
    356       return;
    357     }
    358 
    359     Matcher right_matcher(this->right().node(), true);
    360     if (right_matcher.matches()) {
    361       scale_ = right_matcher.scale();
    362       power_of_two_plus_one_ = right_matcher.power_of_two_plus_one();
    363       this->SwapInputs();
    364       return;
    365     }
    366 
    367     if (this->right().opcode() == kAddOpcode &&
    368         this->left().opcode() != kAddOpcode) {
    369       this->SwapInputs();
    370     }
    371   }
    372 
    373   int scale_;
    374   bool power_of_two_plus_one_;
    375 };
    376 
    377 typedef AddMatcher<Int32BinopMatcher, IrOpcode::kInt32Add, IrOpcode::kInt32Mul,
    378                    IrOpcode::kWord32Shl> Int32AddMatcher;
    379 typedef AddMatcher<Int64BinopMatcher, IrOpcode::kInt64Add, IrOpcode::kInt64Mul,
    380                    IrOpcode::kWord64Shl> Int64AddMatcher;
    381 
    382 
    383 template <class AddMatcher>
    384 struct BaseWithIndexAndDisplacementMatcher {
    385   BaseWithIndexAndDisplacementMatcher(Node* node, bool allow_input_swap)
    386       : matches_(false),
    387         index_(nullptr),
    388         scale_(0),
    389         base_(nullptr),
    390         displacement_(nullptr) {
    391     Initialize(node, allow_input_swap);
    392   }
    393 
    394   explicit BaseWithIndexAndDisplacementMatcher(Node* node)
    395       : matches_(false),
    396         index_(nullptr),
    397         scale_(0),
    398         base_(nullptr),
    399         displacement_(nullptr) {
    400     Initialize(node, node->op()->HasProperty(Operator::kCommutative));
    401   }
    402 
    403   bool matches() const { return matches_; }
    404   Node* index() const { return index_; }
    405   int scale() const { return scale_; }
    406   Node* base() const { return base_; }
    407   Node* displacement() const { return displacement_; }
    408 
    409  private:
    410   bool matches_;
    411   Node* index_;
    412   int scale_;
    413   Node* base_;
    414   Node* displacement_;
    415 
    416   void Initialize(Node* node, bool allow_input_swap) {
    417     // The BaseWithIndexAndDisplacementMatcher canonicalizes the order of
    418     // displacements and scale factors that are used as inputs, so instead of
    419     // enumerating all possible patterns by brute force, checking for node
    420     // clusters using the following templates in the following order suffices to
    421     // find all of the interesting cases (S = index * scale, B = base input, D =
    422     // displacement input):
    423     // (S + (B + D))
    424     // (S + (B + B))
    425     // (S + D)
    426     // (S + B)
    427     // ((S + D) + B)
    428     // ((S + B) + D)
    429     // ((B + D) + B)
    430     // ((B + B) + D)
    431     // (B + D)
    432     // (B + B)
    433     if (node->InputCount() < 2) return;
    434     AddMatcher m(node, allow_input_swap);
    435     Node* left = m.left().node();
    436     Node* right = m.right().node();
    437     Node* displacement = nullptr;
    438     Node* base = nullptr;
    439     Node* index = nullptr;
    440     Node* scale_expression = nullptr;
    441     bool power_of_two_plus_one = false;
    442     int scale = 0;
    443     if (m.HasIndexInput() && left->OwnedBy(node)) {
    444       index = m.IndexInput();
    445       scale = m.scale();
    446       scale_expression = left;
    447       power_of_two_plus_one = m.power_of_two_plus_one();
    448       if (right->opcode() == AddMatcher::kOpcode && right->OwnedBy(node)) {
    449         AddMatcher right_matcher(right);
    450         if (right_matcher.right().HasValue()) {
    451           // (S + (B + D))
    452           base = right_matcher.left().node();
    453           displacement = right_matcher.right().node();
    454         } else {
    455           // (S + (B + B))
    456           base = right;
    457         }
    458       } else if (m.right().HasValue()) {
    459         // (S + D)
    460         displacement = right;
    461       } else {
    462         // (S + B)
    463         base = right;
    464       }
    465     } else {
    466       if (left->opcode() == AddMatcher::kOpcode && left->OwnedBy(node)) {
    467         AddMatcher left_matcher(left);
    468         Node* left_left = left_matcher.left().node();
    469         Node* left_right = left_matcher.right().node();
    470         if (left_matcher.HasIndexInput() && left_left->OwnedBy(left)) {
    471           if (left_matcher.right().HasValue()) {
    472             // ((S + D) + B)
    473             index = left_matcher.IndexInput();
    474             scale = left_matcher.scale();
    475             scale_expression = left_left;
    476             power_of_two_plus_one = left_matcher.power_of_two_plus_one();
    477             displacement = left_right;
    478             base = right;
    479           } else if (m.right().HasValue()) {
    480             // ((S + B) + D)
    481             index = left_matcher.IndexInput();
    482             scale = left_matcher.scale();
    483             scale_expression = left_left;
    484             power_of_two_plus_one = left_matcher.power_of_two_plus_one();
    485             base = left_right;
    486             displacement = right;
    487           } else {
    488             // (B + B)
    489             index = left;
    490             base = right;
    491           }
    492         } else {
    493           if (left_matcher.right().HasValue()) {
    494             // ((B + D) + B)
    495             index = left_left;
    496             displacement = left_right;
    497             base = right;
    498           } else if (m.right().HasValue()) {
    499             // ((B + B) + D)
    500             index = left_left;
    501             base = left_right;
    502             displacement = right;
    503           } else {
    504             // (B + B)
    505             index = left;
    506             base = right;
    507           }
    508         }
    509       } else {
    510         if (m.right().HasValue()) {
    511           // (B + D)
    512           base = left;
    513           displacement = right;
    514         } else {
    515           // (B + B)
    516           base = left;
    517           index = right;
    518         }
    519       }
    520     }
    521     int64_t value = 0;
    522     if (displacement != nullptr) {
    523       switch (displacement->opcode()) {
    524         case IrOpcode::kInt32Constant: {
    525           value = OpParameter<int32_t>(displacement);
    526           break;
    527         }
    528         case IrOpcode::kInt64Constant: {
    529           value = OpParameter<int64_t>(displacement);
    530           break;
    531         }
    532         default:
    533           UNREACHABLE();
    534           break;
    535       }
    536       if (value == 0) {
    537         displacement = nullptr;
    538       }
    539     }
    540     if (power_of_two_plus_one) {
    541       if (base != nullptr) {
    542         // If the scale requires explicitly using the index as the base, but a
    543         // base is already part of the match, then the (1 << N + 1) scale factor
    544         // can't be folded into the match and the entire index * scale
    545         // calculation must be computed separately.
    546         index = scale_expression;
    547         scale = 0;
    548       } else {
    549         base = index;
    550       }
    551     }
    552     base_ = base;
    553     displacement_ = displacement;
    554     index_ = index;
    555     scale_ = scale;
    556     matches_ = true;
    557   }
    558 };
    559 
    560 typedef BaseWithIndexAndDisplacementMatcher<Int32AddMatcher>
    561     BaseWithIndexAndDisplacement32Matcher;
    562 typedef BaseWithIndexAndDisplacementMatcher<Int64AddMatcher>
    563     BaseWithIndexAndDisplacement64Matcher;
    564 
    565 struct BranchMatcher : public NodeMatcher {
    566   explicit BranchMatcher(Node* branch);
    567 
    568   bool Matched() const { return if_true_ && if_false_; }
    569 
    570   Node* Branch() const { return node(); }
    571   Node* IfTrue() const { return if_true_; }
    572   Node* IfFalse() const { return if_false_; }
    573 
    574  private:
    575   Node* if_true_;
    576   Node* if_false_;
    577 };
    578 
    579 
    580 struct DiamondMatcher : public NodeMatcher {
    581   explicit DiamondMatcher(Node* merge);
    582 
    583   bool Matched() const { return branch_; }
    584   bool IfProjectionsAreOwned() const {
    585     return if_true_->OwnedBy(node()) && if_false_->OwnedBy(node());
    586   }
    587 
    588   Node* Branch() const { return branch_; }
    589   Node* IfTrue() const { return if_true_; }
    590   Node* IfFalse() const { return if_false_; }
    591   Node* Merge() const { return node(); }
    592 
    593   Node* TrueInputOf(Node* phi) const {
    594     DCHECK(IrOpcode::IsPhiOpcode(phi->opcode()));
    595     DCHECK_EQ(3, phi->InputCount());
    596     DCHECK_EQ(Merge(), phi->InputAt(2));
    597     return phi->InputAt(if_true_ == Merge()->InputAt(0) ? 0 : 1);
    598   }
    599 
    600   Node* FalseInputOf(Node* phi) const {
    601     DCHECK(IrOpcode::IsPhiOpcode(phi->opcode()));
    602     DCHECK_EQ(3, phi->InputCount());
    603     DCHECK_EQ(Merge(), phi->InputAt(2));
    604     return phi->InputAt(if_true_ == Merge()->InputAt(0) ? 1 : 0);
    605   }
    606 
    607  private:
    608   Node* branch_;
    609   Node* if_true_;
    610   Node* if_false_;
    611 };
    612 
    613 }  // namespace compiler
    614 }  // namespace internal
    615 }  // namespace v8
    616 
    617 #endif  // V8_COMPILER_NODE_MATCHERS_H_
    618