Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 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_AST_AST_NUMBERING_H_ |
| 6 | #define V8_AST_AST_NUMBERING_H_ |
| 7 | |
| 8 | namespace v8 { |
| 9 | namespace internal { |
| 10 | |
| 11 | // Forward declarations. |
| 12 | class FunctionLiteral; |
| 13 | class Isolate; |
| 14 | class Zone; |
| 15 | |
| 16 | namespace AstNumbering { |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame^] | 17 | // Assign type feedback IDs, bailout IDs, and generator yield IDs to an AST node |
| 18 | // tree. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 19 | bool Renumber(Isolate* isolate, Zone* zone, FunctionLiteral* function); |
| 20 | } |
| 21 | |
Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame^] | 22 | // Some details on yield IDs |
| 23 | // ------------------------- |
| 24 | // |
| 25 | // In order to assist Ignition in generating bytecode for a generator function, |
| 26 | // we assign a unique number (the yield ID) to each Yield node in its AST. We |
| 27 | // also annotate loops with the number of yields they contain (loop.yield_count) |
| 28 | // and the smallest ID of those (loop.first_yield_id), and we annotate the |
| 29 | // function itself with the number of yields it contains (function.yield_count). |
| 30 | // |
| 31 | // The way in which we choose the IDs is simply by enumerating the Yield nodes. |
| 32 | // Ignition relies on the following properties: |
| 33 | // - For each loop l and each yield y of l: |
| 34 | // l.first_yield_id <= y.yield_id < l.first_yield_id + l.yield_count |
| 35 | // - For the generator function f itself and each yield y of f: |
| 36 | // 0 <= y.yield_id < f.yield_count |
| 37 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 38 | } // namespace internal |
| 39 | } // namespace v8 |
| 40 | |
| 41 | #endif // V8_AST_AST_NUMBERING_H_ |