1 // Copyright 2010 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_LIVEEDIT_H_ 29 #define V8_LIVEEDIT_H_ 30 31 32 33 // Live Edit feature implementation. 34 // User should be able to change script on already running VM. This feature 35 // matches hot swap features in other frameworks. 36 // 37 // The basic use-case is when user spots some mistake in function body 38 // from debugger and wishes to change the algorithm without restart. 39 // 40 // A single change always has a form of a simple replacement (in pseudo-code): 41 // script.source[positions, positions+length] = new_string; 42 // Implementation first determines, which function's body includes this 43 // change area. Then both old and new versions of script are fully compiled 44 // in order to analyze, whether the function changed its outer scope 45 // expectations (or number of parameters). If it didn't, function's code is 46 // patched with a newly compiled code. If it did change, enclosing function 47 // gets patched. All inner functions are left untouched, whatever happened 48 // to them in a new script version. However, new version of code will 49 // instantiate newly compiled functions. 50 51 52 #include "compiler.h" 53 54 namespace v8 { 55 namespace internal { 56 57 // This class collects some specific information on structure of functions 58 // in a particular script. It gets called from compiler all the time, but 59 // actually records any data only when liveedit operation is in process; 60 // in any other time this class is very cheap. 61 // 62 // The primary interest of the Tracker is to record function scope structures 63 // in order to analyze whether function code maybe safely patched (with new 64 // code successfully reading existing data from function scopes). The Tracker 65 // also collects compiled function codes. 66 class LiveEditFunctionTracker { 67 public: 68 explicit LiveEditFunctionTracker(FunctionLiteral* fun); 69 ~LiveEditFunctionTracker(); 70 void RecordFunctionCode(Handle<Code> code); 71 void RecordFunctionScope(Scope* scope); 72 73 static bool IsActive(); 74 }; 75 76 } } // namespace v8::internal 77 78 #endif /* V*_LIVEEDIT_H_ */ 79
