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 { 17 // Assign type feedback IDs, bailout IDs, and generator yield IDs to an AST node 18 // tree. 19 bool Renumber(Isolate* isolate, Zone* zone, FunctionLiteral* function); 20 } 21 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 38 } // namespace internal 39 } // namespace v8 40 41 #endif // V8_AST_AST_NUMBERING_H_ 42
