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src/compiler/schedule.h

Index: src/compiler/schedule.h
diff --git a/src/compiler/schedule.h b/src/compiler/schedule.h
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+// 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.
+
+#ifndef V8_COMPILER_SCHEDULE_H_
+#define V8_COMPILER_SCHEDULE_H_
+
+#include <vector>
+
+#include "src/v8.h"
+
+#include "src/compiler/generic-algorithm.h"
+#include "src/compiler/generic-graph.h"
+#include "src/compiler/generic-node.h"
+#include "src/compiler/generic-node-inl.h"
+#include "src/compiler/node.h"
+#include "src/compiler/opcodes.h"
+#include "src/zone.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class BasicBlock;
+class Graph;
+class ConstructScheduleData;
+class CodeGenerator;  // Because of a namespace bug in clang.
+
+class BasicBlockData {
+ public:
+  // Possible control nodes that can end a block.
+  enum Control {
+    kNone,       // Control not initialized yet.
+    kGoto,       // Goto a single successor block.
+    kBranch,     // Branch if true to first successor, otherwise second.
+    kReturn,     // Return a value from this method.
+    kThrow,      // Throw an exception.
+    kCall,       // Call to a possibly deoptimizing or throwing function.
+    kDeoptimize  // Deoptimize.
+  };
+
+  int32_t rpo_number_;       // special RPO number of the block.
+  BasicBlock* loop_header_;  // Pointer to dominating loop header basic block,
+                             // NULL if none. For loop headers, this points to
+                             // enclosing loop header.
+  int32_t loop_depth_;       // loop nesting, 0 is top-level
+  int32_t loop_end_;         // end of the loop, if this block is a loop header.
+  int32_t code_start_;       // start index of arch-specific code.
+  int32_t code_end_;         // end index of arch-specific code.
+  bool deferred_;            // {true} if this block is considered the slow
+                             // path.
+  Control control_;          // Control at the end of the block.
+  Node* control_input_;      // Input value for control.
+  NodeVector nodes_;         // nodes of this block in forward order.
+
+  explicit BasicBlockData(Zone* zone)
+      : rpo_number_(-1),
+        loop_header_(NULL),
+        loop_depth_(0),
+        loop_end_(-1),
+        code_start_(-1),
+        code_end_(-1),
+        deferred_(false),
+        control_(kNone),
+        control_input_(NULL),
+        nodes_(NodeVector::allocator_type(zone)) {}
+
+  inline bool IsLoopHeader() const { return loop_end_ >= 0; }
+  inline bool LoopContains(BasicBlockData* block) const {
+    // RPO numbers must be initialized.
+    ASSERT(rpo_number_ >= 0);
+    ASSERT(block->rpo_number_ >= 0);
+    if (loop_end_ < 0) return false;  // This is not a loop.
+    return block->rpo_number_ >= rpo_number_ && block->rpo_number_ < loop_end_;
+  }
+  int first_instruction_index() {
+    ASSERT(code_start_ >= 0);
+    ASSERT(code_end_ > 0);
+    ASSERT(code_end_ >= code_start_);
+    return code_start_;
+  }
+  int last_instruction_index() {
+    ASSERT(code_start_ >= 0);
+    ASSERT(code_end_ > 0);
+    ASSERT(code_end_ >= code_start_);
+    return code_end_ - 1;
+  }
+};
+
+OStream& operator<<(OStream& os, const BasicBlockData::Control& c);
+
+// A basic block contains an ordered list of nodes and ends with a control
+// node. Note that if a basic block has phis, then all phis must appear as the
+// first nodes in the block.
+class BasicBlock V8_FINAL : public GenericNode<BasicBlockData, BasicBlock> {
+ public:
+  BasicBlock(GenericGraphBase* graph, int input_count)
+      : GenericNode<BasicBlockData, BasicBlock>(graph, input_count) {}
+
+  typedef Uses Successors;
+  typedef Inputs Predecessors;
+
+  Successors successors() { return static_cast<Successors>(uses()); }
+  Predecessors predecessors() { return static_cast<Predecessors>(inputs()); }
+
+  int PredecessorCount() { return InputCount(); }
+  BasicBlock* PredecessorAt(int index) { return InputAt(index); }
+
+  int SuccessorCount() { return UseCount(); }
+  BasicBlock* SuccessorAt(int index) { return UseAt(index); }
+
+  int PredecessorIndexOf(BasicBlock* predecessor) {
+    BasicBlock::Predecessors predecessors = this->predecessors();
+    for (BasicBlock::Predecessors::iterator i = predecessors.begin();
+         i != predecessors.end(); ++i) {
+      if (*i == predecessor) return i.index();
+    }
+    return -1;
+  }
+
+  inline BasicBlock* loop_header() {
+    return static_cast<BasicBlock*>(loop_header_);
+  }
+  inline BasicBlock* ContainingLoop() {
+    if (IsLoopHeader()) return this;
+    return static_cast<BasicBlock*>(loop_header_);
+  }
+
+  typedef NodeVector::iterator iterator;
+  iterator begin() { return nodes_.begin(); }
+  iterator end() { return nodes_.end(); }
+
+  typedef NodeVector::const_iterator const_iterator;
+  const_iterator begin() const { return nodes_.begin(); }
+  const_iterator end() const { return nodes_.end(); }
+
+  typedef NodeVector::reverse_iterator reverse_iterator;
+  reverse_iterator rbegin() { return nodes_.rbegin(); }
+  reverse_iterator rend() { return nodes_.rend(); }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BasicBlock);
+};
+
+typedef GenericGraphVisit::NullNodeVisitor<BasicBlockData, BasicBlock>
+    NullBasicBlockVisitor;
+
+typedef zone_allocator<BasicBlock*> BasicBlockPtrZoneAllocator;
+typedef std::vector<BasicBlock*, BasicBlockPtrZoneAllocator> BasicBlockVector;
+typedef BasicBlockVector::iterator BasicBlockVectorIter;
+typedef BasicBlockVector::reverse_iterator BasicBlockVectorRIter;
+
+// A schedule represents the result of assigning nodes to basic blocks
+// and ordering them within basic blocks. Prior to computing a schedule,
+// a graph has no notion of control flow ordering other than that induced
+// by the graph's dependencies. A schedule is required to generate code.
+class Schedule : public GenericGraph<BasicBlock> {
+ public:
+  explicit Schedule(Zone* zone)
+      : GenericGraph<BasicBlock>(zone),
+        zone_(zone),
+        all_blocks_(BasicBlockVector::allocator_type(zone)),
+        nodeid_to_block_(BasicBlockVector::allocator_type(zone)),
+        rpo_order_(BasicBlockVector::allocator_type(zone)),
+        immediate_dominator_(BasicBlockVector::allocator_type(zone)) {
+    NewBasicBlock();  // entry.
+    NewBasicBlock();  // exit.
+    SetStart(entry());
+    SetEnd(exit());
+  }
+
+  // TODO(titzer): rewrite users of these methods to use start() and end().
+  BasicBlock* entry() const { return all_blocks_[0]; }  // Return entry block.
+  BasicBlock* exit() const { return all_blocks_[1]; }   // Return exit block.
+
+  // Return the block which contains {node}, if any.
+  BasicBlock* block(Node* node) const {
+    if (node->id() < static_cast<NodeId>(nodeid_to_block_.size())) {
+      return nodeid_to_block_[node->id()];
+    }
+    return NULL;
+  }
+
+  BasicBlock* dominator(BasicBlock* block) {
+    return immediate_dominator_[block->id()];
+  }
+
+  bool IsScheduled(Node* node) {
+    int length = static_cast<int>(nodeid_to_block_.size());
+    if (node->id() >= length) return false;
+    return nodeid_to_block_[node->id()] != NULL;
+  }
+
+  BasicBlock* GetBlockById(int block_id) { return all_blocks_[block_id]; }
+
+  int BasicBlockCount() const { return NodeCount(); }
+  int RpoBlockCount() const { return rpo_order_.size(); }
+
+  typedef ContainerPointerWrapper<BasicBlockVector> BasicBlocks;
+
+  // Return a list of all the blocks in the schedule, in arbitrary order.
+  BasicBlocks all_blocks() { return BasicBlocks(&all_blocks_); }
+
+  // Check if nodes {a} and {b} are in the same block.
+  inline bool SameBasicBlock(Node* a, Node* b) const {
+    BasicBlock* block = this->block(a);
+    return block != NULL && block == this->block(b);
+  }
+
+  // BasicBlock building: create a new block.
+  inline BasicBlock* NewBasicBlock() {
+    BasicBlock* block =
+        BasicBlock::New(this, 0, static_cast<BasicBlock**>(NULL));
+    all_blocks_.push_back(block);
+    return block;
+  }
+
+  // BasicBlock building: records that a node will later be added to a block but
+  // doesn't actually add the node to the block.
+  inline void PlanNode(BasicBlock* block, Node* node) {
+    if (FLAG_trace_turbo_scheduler) {
+      PrintF("Planning node %d for future add to block %d\n", node->id(),
+             block->id());
+    }
+    ASSERT(this->block(node) == NULL);
+    SetBlockForNode(block, node);
+  }
+
+  // BasicBlock building: add a node to the end of the block.
+  inline void AddNode(BasicBlock* block, Node* node) {
+    if (FLAG_trace_turbo_scheduler) {
+      PrintF("Adding node %d to block %d\n", node->id(), block->id());
+    }
+    ASSERT(this->block(node) == NULL || this->block(node) == block);
+    block->nodes_.push_back(node);
+    SetBlockForNode(block, node);
+  }
+
+  // BasicBlock building: add a goto to the end of {block}.
+  void AddGoto(BasicBlock* block, BasicBlock* succ) {
+    ASSERT(block->control_ == BasicBlock::kNone);
+    block->control_ = BasicBlock::kGoto;
+    AddSuccessor(block, succ);
+  }
+
+  // BasicBlock building: add a (branching) call at the end of {block}.
+  void AddCall(BasicBlock* block, Node* call, BasicBlock* cont_block,
+               BasicBlock* deopt_block) {
+    ASSERT(block->control_ == BasicBlock::kNone);
+    ASSERT(call->opcode() == IrOpcode::kCall);
+    block->control_ = BasicBlock::kCall;
+    // Insert the deopt block first so that the RPO order builder picks
+    // it first (and thus it ends up late in the RPO order).
+    AddSuccessor(block, deopt_block);
+    AddSuccessor(block, cont_block);
+    SetControlInput(block, call);
+  }
+
+  // BasicBlock building: add a branch at the end of {block}.
+  void AddBranch(BasicBlock* block, Node* branch, BasicBlock* tblock,
+                 BasicBlock* fblock) {
+    ASSERT(block->control_ == BasicBlock::kNone);
+    ASSERT(branch->opcode() == IrOpcode::kBranch);
+    block->control_ = BasicBlock::kBranch;
+    AddSuccessor(block, tblock);
+    AddSuccessor(block, fblock);
+    SetControlInput(block, branch);
+  }
+
+  // BasicBlock building: add a return at the end of {block}.
+  void AddReturn(BasicBlock* block, Node* input) {
+    // TODO(titzer): require a Return node here.
+    ASSERT(block->control_ == BasicBlock::kNone);
+    block->control_ = BasicBlock::kReturn;
+    SetControlInput(block, input);
+    if (block != exit()) AddSuccessor(block, exit());
+  }
+
+  // BasicBlock building: add a throw at the end of {block}.
+  void AddThrow(BasicBlock* block, Node* input) {
+    ASSERT(block->control_ == BasicBlock::kNone);
+    block->control_ = BasicBlock::kThrow;
+    SetControlInput(block, input);
+    if (block != exit()) AddSuccessor(block, exit());
+  }
+
+  // BasicBlock building: add a deopt at the end of {block}.
+  void AddDeoptimize(BasicBlock* block, Node* state) {
+    ASSERT(block->control_ == BasicBlock::kNone);
+    block->control_ = BasicBlock::kDeoptimize;
+    SetControlInput(block, state);
+    block->deferred_ = true;  // By default, consider deopts the slow path.
+    if (block != exit()) AddSuccessor(block, exit());
+  }
+
+  friend class Scheduler;
+  friend class CodeGenerator;
+
+  void AddSuccessor(BasicBlock* block, BasicBlock* succ) {
+    succ->AppendInput(zone_, block);
+  }
+
+  BasicBlockVector* rpo_order() { return &rpo_order_; }
+
+ private:
+  friend class ScheduleVisualizer;
+
+  void SetControlInput(BasicBlock* block, Node* node) {
+    block->control_input_ = node;
+    SetBlockForNode(block, node);
+  }
+
+  void SetBlockForNode(BasicBlock* block, Node* node) {
+    int length = static_cast<int>(nodeid_to_block_.size());
+    if (node->id() >= length) {
+      nodeid_to_block_.resize(node->id() + 1);
+    }
+    nodeid_to_block_[node->id()] = block;
+  }
+
+  Zone* zone_;
+  BasicBlockVector all_blocks_;           // All basic blocks in the schedule.
+  BasicBlockVector nodeid_to_block_;      // Map from node to containing block.
+  BasicBlockVector rpo_order_;            // Reverse-post-order block list.
+  BasicBlockVector immediate_dominator_;  // Maps to a block's immediate
+                                          // dominator, indexed by block
+                                          // id.
+};
+
+OStream& operator<<(OStream& os, const Schedule& s);
+}
+}
+}  // namespace v8::internal::compiler
+
+#endif  // V8_COMPILER_SCHEDULE_H_