Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2015 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_MARKER_H_ |
| 6 | #define V8_COMPILER_NODE_MARKER_H_ |
| 7 | |
| 8 | #include "src/compiler/node.h" |
| 9 | |
| 10 | namespace v8 { |
| 11 | namespace internal { |
| 12 | namespace compiler { |
| 13 | |
| 14 | // Forward declarations. |
| 15 | class Graph; |
| 16 | |
| 17 | |
| 18 | // Base class for templatized NodeMarkers. |
| 19 | class NodeMarkerBase { |
| 20 | public: |
| 21 | NodeMarkerBase(Graph* graph, uint32_t num_states); |
| 22 | |
| 23 | V8_INLINE Mark Get(Node* node) { |
| 24 | Mark mark = node->mark(); |
| 25 | if (mark < mark_min_) { |
| 26 | mark = mark_min_; |
| 27 | node->set_mark(mark_min_); |
| 28 | } |
| 29 | DCHECK_LT(mark, mark_max_); |
| 30 | return mark - mark_min_; |
| 31 | } |
| 32 | V8_INLINE void Set(Node* node, Mark mark) { |
| 33 | DCHECK_LT(mark, mark_max_ - mark_min_); |
| 34 | DCHECK_LT(node->mark(), mark_max_); |
| 35 | node->set_mark(mark + mark_min_); |
| 36 | } |
| 37 | |
| 38 | private: |
| 39 | Mark const mark_min_; |
| 40 | Mark const mark_max_; |
| 41 | |
| 42 | DISALLOW_COPY_AND_ASSIGN(NodeMarkerBase); |
| 43 | }; |
| 44 | |
Ben Murdoch | 61f157c | 2016-09-16 13:49:30 +0100 | [diff] [blame] | 45 | // A NodeMarker assigns a local "state" to every node of a graph in constant |
| 46 | // memory. Only one NodeMarker per graph is valid at a given time, that is, |
| 47 | // after you create a NodeMarker you should no longer use NodeMarkers that |
| 48 | // were created earlier. Internally, the local state is stored in the Node |
| 49 | // structure. |
| 50 | // |
| 51 | // When you initialize a NodeMarker, all the local states are conceptually |
| 52 | // set to State(0) in constant time. |
| 53 | // |
| 54 | // In its current implementation, in debug mode NodeMarker will try to |
| 55 | // (efficiently) detect invalid use of an older NodeMarker. Namely, if you get |
| 56 | // or set a node with a NodeMarker, and then get or set that node |
| 57 | // with an older NodeMarker you will get a crash. |
| 58 | // |
| 59 | // GraphReducer uses a NodeMarker, so individual Reducers cannot use a |
| 60 | // NodeMarker. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 61 | template <typename State> |
| 62 | class NodeMarker : public NodeMarkerBase { |
| 63 | public: |
| 64 | V8_INLINE NodeMarker(Graph* graph, uint32_t num_states) |
| 65 | : NodeMarkerBase(graph, num_states) {} |
| 66 | |
| 67 | V8_INLINE State Get(Node* node) { |
| 68 | return static_cast<State>(NodeMarkerBase::Get(node)); |
| 69 | } |
| 70 | |
| 71 | V8_INLINE void Set(Node* node, State state) { |
| 72 | NodeMarkerBase::Set(node, static_cast<Mark>(state)); |
| 73 | } |
| 74 | }; |
| 75 | |
| 76 | } // namespace compiler |
| 77 | } // namespace internal |
| 78 | } // namespace v8 |
| 79 | |
| 80 | #endif // V8_COMPILER_NODE_MARKER_H_ |