Line data Source code
1 : // Copyright 2013 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_SCHEDULE_H_
6 : #define V8_COMPILER_SCHEDULE_H_
7 :
8 : #include <iosfwd>
9 :
10 : #include "src/base/compiler-specific.h"
11 : #include "src/globals.h"
12 : #include "src/zone/zone-containers.h"
13 :
14 : namespace v8 {
15 : namespace internal {
16 : namespace compiler {
17 :
18 : // Forward declarations.
19 : class BasicBlock;
20 : class BasicBlockInstrumentor;
21 : class Node;
22 :
23 : typedef ZoneVector<BasicBlock*> BasicBlockVector;
24 : typedef ZoneVector<Node*> NodeVector;
25 :
26 : // A basic block contains an ordered list of nodes and ends with a control
27 : // node. Note that if a basic block has phis, then all phis must appear as the
28 : // first nodes in the block.
29 : class V8_EXPORT_PRIVATE BasicBlock final
30 : : public NON_EXPORTED_BASE(ZoneObject) {
31 : public:
32 : // Possible control nodes that can end a block.
33 : enum Control {
34 : kNone, // Control not initialized yet.
35 : kGoto, // Goto a single successor block.
36 : kCall, // Call with continuation as first successor, exception
37 : // second.
38 : kBranch, // Branch if true to first successor, otherwise second.
39 : kSwitch, // Table dispatch to one of the successor blocks.
40 : kDeoptimize, // Return a value from this method.
41 : kTailCall, // Tail call another method from this method.
42 : kReturn, // Return a value from this method.
43 : kThrow // Throw an exception.
44 : };
45 :
46 : class Id {
47 : public:
48 6060269 : int ToInt() const { return static_cast<int>(index_); }
49 12870449 : size_t ToSize() const { return index_; }
50 : static Id FromSize(size_t index) { return Id(index); }
51 12869800 : static Id FromInt(int index) { return Id(static_cast<size_t>(index)); }
52 :
53 : private:
54 : explicit Id(size_t index) : index_(index) {}
55 : size_t index_;
56 : };
57 :
58 : BasicBlock(Zone* zone, Id id);
59 :
60 : Id id() const { return id_; }
61 : #if DEBUG
62 : void set_debug_info(AssemblerDebugInfo debug_info) {
63 : debug_info_ = debug_info;
64 : }
65 : AssemblerDebugInfo debug_info() const { return debug_info_; }
66 : #endif // DEBUG
67 :
68 : // Predecessors.
69 : BasicBlockVector& predecessors() { return predecessors_; }
70 : const BasicBlockVector& predecessors() const { return predecessors_; }
71 37834094 : size_t PredecessorCount() const { return predecessors_.size(); }
72 27184066 : BasicBlock* PredecessorAt(size_t index) { return predecessors_[index]; }
73 : void ClearPredecessors() { predecessors_.clear(); }
74 : void AddPredecessor(BasicBlock* predecessor);
75 :
76 : // Successors.
77 : BasicBlockVector& successors() { return successors_; }
78 : const BasicBlockVector& successors() const { return successors_; }
79 85909550 : size_t SuccessorCount() const { return successors_.size(); }
80 66216574 : BasicBlock* SuccessorAt(size_t index) { return successors_[index]; }
81 : void ClearSuccessors() { successors_.clear(); }
82 : void AddSuccessor(BasicBlock* successor);
83 :
84 : // Nodes in the basic block.
85 : typedef Node* value_type;
86 : bool empty() const { return nodes_.empty(); }
87 : size_t size() const { return nodes_.size(); }
88 42014010 : Node* NodeAt(size_t index) { return nodes_[index]; }
89 39049120 : size_t NodeCount() const { return nodes_.size(); }
90 :
91 : value_type& front() { return nodes_.front(); }
92 : value_type const& front() const { return nodes_.front(); }
93 :
94 : typedef NodeVector::iterator iterator;
95 : iterator begin() { return nodes_.begin(); }
96 : iterator end() { return nodes_.end(); }
97 :
98 : typedef NodeVector::const_iterator const_iterator;
99 : const_iterator begin() const { return nodes_.begin(); }
100 : const_iterator end() const { return nodes_.end(); }
101 :
102 : typedef NodeVector::reverse_iterator reverse_iterator;
103 : reverse_iterator rbegin() { return nodes_.rbegin(); }
104 : reverse_iterator rend() { return nodes_.rend(); }
105 :
106 : void AddNode(Node* node);
107 : template <class InputIterator>
108 : void InsertNodes(iterator insertion_point, InputIterator insertion_start,
109 : InputIterator insertion_end) {
110 56 : nodes_.insert(insertion_point, insertion_start, insertion_end);
111 : }
112 :
113 : // Accessors.
114 : Control control() const { return control_; }
115 : void set_control(Control control);
116 :
117 : Node* control_input() const { return control_input_; }
118 : void set_control_input(Node* control_input);
119 :
120 : bool deferred() const { return deferred_; }
121 28983111 : void set_deferred(bool deferred) { deferred_ = deferred; }
122 :
123 : int32_t dominator_depth() const { return dominator_depth_; }
124 38167585 : void set_dominator_depth(int32_t depth) { dominator_depth_ = depth; }
125 :
126 : BasicBlock* dominator() const { return dominator_; }
127 37204117 : void set_dominator(BasicBlock* dominator) { dominator_ = dominator; }
128 :
129 : BasicBlock* rpo_next() const { return rpo_next_; }
130 22449005 : void set_rpo_next(BasicBlock* rpo_next) { rpo_next_ = rpo_next; }
131 :
132 : BasicBlock* loop_header() const { return loop_header_; }
133 : void set_loop_header(BasicBlock* loop_header);
134 :
135 : BasicBlock* loop_end() const { return loop_end_; }
136 : void set_loop_end(BasicBlock* loop_end);
137 :
138 : int32_t loop_depth() const { return loop_depth_; }
139 : void set_loop_depth(int32_t loop_depth);
140 :
141 : int32_t loop_number() const { return loop_number_; }
142 147231 : void set_loop_number(int32_t loop_number) { loop_number_ = loop_number; }
143 :
144 : int32_t rpo_number() const { return rpo_number_; }
145 : void set_rpo_number(int32_t rpo_number);
146 :
147 : // Loop membership helpers.
148 : inline bool IsLoopHeader() const { return loop_end_ != nullptr; }
149 : bool LoopContains(BasicBlock* block) const;
150 :
151 : // Computes the immediate common dominator of {b1} and {b2}. The worst time
152 : // complexity is O(N) where N is the height of the dominator tree.
153 : static BasicBlock* GetCommonDominator(BasicBlock* b1, BasicBlock* b2);
154 :
155 : private:
156 : int32_t loop_number_; // loop number of the block.
157 : int32_t rpo_number_; // special RPO number of the block.
158 : bool deferred_; // true if the block contains deferred code.
159 : int32_t dominator_depth_; // Depth within the dominator tree.
160 : BasicBlock* dominator_; // Immediate dominator of the block.
161 : BasicBlock* rpo_next_; // Link to next block in special RPO order.
162 : BasicBlock* loop_header_; // Pointer to dominating loop header basic block,
163 : // nullptr if none. For loop headers, this points to
164 : // enclosing loop header.
165 : BasicBlock* loop_end_; // end of the loop, if this block is a loop header.
166 : int32_t loop_depth_; // loop nesting, 0 is top-level
167 :
168 : Control control_; // Control at the end of the block.
169 : Node* control_input_; // Input value for control.
170 : NodeVector nodes_; // nodes of this block in forward order.
171 :
172 : BasicBlockVector successors_;
173 : BasicBlockVector predecessors_;
174 : #if DEBUG
175 : AssemblerDebugInfo debug_info_;
176 : #endif
177 : Id id_;
178 :
179 : DISALLOW_COPY_AND_ASSIGN(BasicBlock);
180 : };
181 :
182 : std::ostream& operator<<(std::ostream&, const BasicBlock&);
183 : std::ostream& operator<<(std::ostream&, const BasicBlock::Control&);
184 : std::ostream& operator<<(std::ostream&, const BasicBlock::Id&);
185 :
186 :
187 : // A schedule represents the result of assigning nodes to basic blocks
188 : // and ordering them within basic blocks. Prior to computing a schedule,
189 : // a graph has no notion of control flow ordering other than that induced
190 : // by the graph's dependencies. A schedule is required to generate code.
191 : class V8_EXPORT_PRIVATE Schedule final : public NON_EXPORTED_BASE(ZoneObject) {
192 : public:
193 : explicit Schedule(Zone* zone, size_t node_count_hint = 0);
194 :
195 : // Return the block which contains {node}, if any.
196 : BasicBlock* block(Node* node) const;
197 :
198 : bool IsScheduled(Node* node);
199 : BasicBlock* GetBlockById(BasicBlock::Id block_id);
200 :
201 18597642 : size_t BasicBlockCount() const { return all_blocks_.size(); }
202 28 : size_t RpoBlockCount() const { return rpo_order_.size(); }
203 :
204 : // Check if nodes {a} and {b} are in the same block.
205 : bool SameBasicBlock(Node* a, Node* b) const;
206 :
207 : // BasicBlock building: create a new block.
208 : BasicBlock* NewBasicBlock();
209 :
210 : // BasicBlock building: records that a node will later be added to a block but
211 : // doesn't actually add the node to the block.
212 : void PlanNode(BasicBlock* block, Node* node);
213 :
214 : // BasicBlock building: add a node to the end of the block.
215 : void AddNode(BasicBlock* block, Node* node);
216 :
217 : // BasicBlock building: add a goto to the end of {block}.
218 : void AddGoto(BasicBlock* block, BasicBlock* succ);
219 :
220 : // BasicBlock building: add a call at the end of {block}.
221 : void AddCall(BasicBlock* block, Node* call, BasicBlock* success_block,
222 : BasicBlock* exception_block);
223 :
224 : // BasicBlock building: add a branch at the end of {block}.
225 : void AddBranch(BasicBlock* block, Node* branch, BasicBlock* tblock,
226 : BasicBlock* fblock);
227 :
228 : // BasicBlock building: add a switch at the end of {block}.
229 : void AddSwitch(BasicBlock* block, Node* sw, BasicBlock** succ_blocks,
230 : size_t succ_count);
231 :
232 : // BasicBlock building: add a deoptimize at the end of {block}.
233 : void AddDeoptimize(BasicBlock* block, Node* input);
234 :
235 : // BasicBlock building: add a tailcall at the end of {block}.
236 : void AddTailCall(BasicBlock* block, Node* input);
237 :
238 : // BasicBlock building: add a return at the end of {block}.
239 : void AddReturn(BasicBlock* block, Node* input);
240 :
241 : // BasicBlock building: add a throw at the end of {block}.
242 : void AddThrow(BasicBlock* block, Node* input);
243 :
244 : // BasicBlock mutation: insert a branch into the end of {block}.
245 : void InsertBranch(BasicBlock* block, BasicBlock* end, Node* branch,
246 : BasicBlock* tblock, BasicBlock* fblock);
247 :
248 : // BasicBlock mutation: insert a switch into the end of {block}.
249 : void InsertSwitch(BasicBlock* block, BasicBlock* end, Node* sw,
250 : BasicBlock** succ_blocks, size_t succ_count);
251 :
252 : // Exposed publicly for testing only.
253 : void AddSuccessorForTesting(BasicBlock* block, BasicBlock* succ) {
254 : return AddSuccessor(block, succ);
255 : }
256 :
257 : const BasicBlockVector* all_blocks() const { return &all_blocks_; }
258 : BasicBlockVector* rpo_order() { return &rpo_order_; }
259 : const BasicBlockVector* rpo_order() const { return &rpo_order_; }
260 :
261 : BasicBlock* start() { return start_; }
262 : BasicBlock* end() { return end_; }
263 :
264 : Zone* zone() const { return zone_; }
265 :
266 : private:
267 : friend class Scheduler;
268 : friend class BasicBlockInstrumentor;
269 : friend class RawMachineAssembler;
270 :
271 : // Ensure properties of the CFG assumed by further stages.
272 : void EnsureCFGWellFormedness();
273 : // Ensure split-edge form for a hand-assembled schedule.
274 : void EnsureSplitEdgeForm(BasicBlock* block);
275 : // Ensure entry into a deferred block happens from a single hot block.
276 : void EnsureDeferredCodeSingleEntryPoint(BasicBlock* block);
277 : // Copy deferred block markers down as far as possible
278 : void PropagateDeferredMark();
279 :
280 : void AddSuccessor(BasicBlock* block, BasicBlock* succ);
281 : void MoveSuccessors(BasicBlock* from, BasicBlock* to);
282 :
283 : void SetControlInput(BasicBlock* block, Node* node);
284 : void SetBlockForNode(BasicBlock* block, Node* node);
285 :
286 : Zone* zone_;
287 : BasicBlockVector all_blocks_; // All basic blocks in the schedule.
288 : BasicBlockVector nodeid_to_block_; // Map from node to containing block.
289 : BasicBlockVector rpo_order_; // Reverse-post-order block list.
290 : BasicBlock* start_;
291 : BasicBlock* end_;
292 :
293 : DISALLOW_COPY_AND_ASSIGN(Schedule);
294 : };
295 :
296 : V8_EXPORT_PRIVATE std::ostream& operator<<(std::ostream&, const Schedule&);
297 :
298 : } // namespace compiler
299 : } // namespace internal
300 : } // namespace v8
301 :
302 : #endif // V8_COMPILER_SCHEDULE_H_
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