v8/src/liveedit.h

107 lines
4.4 KiB
C++

// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_LIVEEDIT_H_
#define V8_LIVEEDIT_H_
// Live Edit feature implementation.
// User should be able to change script on already running VM. This feature
// matches hot swap features in other frameworks.
//
// The basic use-case is when user spots some mistake in function body
// from debugger and wishes to change the algorithm without restart.
//
// A single change always has a form of a simple replacement (in pseudo-code):
// script.source[positions, positions+length] = new_string;
// Implementation first determines, which function's body includes this
// change area. Then both old and new versions of script are fully compiled
// in order to analyze, whether the function changed its outer scope
// expectations (or number of parameters). If it didn't, function's code is
// patched with a newly compiled code. If it did change, enclosing function
// gets patched. All inner functions are left untouched, whatever happened
// to them in a new script version. However, new version of code will
// instantiate newly compiled functions.
#include "compiler.h"
namespace v8 {
namespace internal {
// This class collects some specific information on structure of functions
// in a particular script. It gets called from compiler all the time, but
// actually records any data only when liveedit operation is in process;
// in any other time this class is very cheap.
//
// The primary interest of the Tracker is to record function scope structures
// in order to analyze whether function code maybe safely patched (with new
// code successfully reading existing data from function scopes). The Tracker
// also collects compiled function codes.
class LiveEditFunctionTracker {
public:
explicit LiveEditFunctionTracker(FunctionLiteral* fun);
~LiveEditFunctionTracker();
void RecordFunctionCode(Handle<Code> code);
void RecordFunctionScope(Scope* scope);
static bool IsActive();
};
#ifdef ENABLE_DEBUGGER_SUPPORT
class LiveEdit : AllStatic {
public:
static JSArray* GatherCompileInfo(Handle<Script> script,
Handle<String> source);
static void WrapSharedFunctionInfos(Handle<JSArray> array);
static void ReplaceFunctionCode(Handle<JSArray> new_compile_info_array,
Handle<JSArray> shared_info_array);
static void RelinkFunctionToScript(Handle<JSArray> shared_info_array,
Handle<Script> script_handle);
static void PatchFunctionPositions(Handle<JSArray> shared_info_array,
Handle<JSArray> position_change_array);
// A copy of this is in liveedit-delay.js.
enum FunctionPatchabilityStatus {
FUNCTION_AVAILABLE_FOR_PATCH = 0,
FUNCTION_BLOCKED_ON_STACK = 1
};
};
#endif // ENABLE_DEBUGGER_SUPPORT
} } // namespace v8::internal
#endif /* V*_LIVEEDIT_H_ */