| // 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. |
| |
| // LiveEdit feature implementation. The script should be executed after |
| // debug-delay.js. |
| |
| |
| // Changes script text and recompiles all relevant functions if possible. |
| // The change is always a substring (change_pos, change_pos + change_len) |
| // being replaced with a completely different string new_str. |
| // |
| // Only one function will have its Code changed in result of this function. |
| // All nested functions (should they have any instances at the moment) are left |
| // unchanged and re-linked to a newly created script instance representing old |
| // version of the source. (Generally speaking, |
| // during the change all nested functions are erased and completely different |
| // set of nested functions are introduced.) All other functions just have |
| // their positions updated. |
| // |
| // @param {Script} script that is being changed |
| // @param {Array} change_log a list that collects engineer-readable description |
| // of what happened. |
| Debug.LiveEditChangeScript = function(script, change_pos, change_len, new_str, |
| change_log) { |
| |
| // So far the function works as namespace. |
| var liveedit = Debug.LiveEditChangeScript; |
| var Assert = liveedit.Assert; |
| |
| // Fully compiles source string as a script. Returns Array of |
| // FunctionCompileInfo -- a descriptions of all functions of the script. |
| // Elements of array are ordered by start positions of functions (from top |
| // to bottom) in the source. Fields outer_index and next_sibling_index help |
| // to navigate the nesting structure of functions. |
| // |
| // The script is used for compilation, because it produces code that |
| // needs to be linked with some particular script (for nested functions). |
| function DebugGatherCompileInfo(source) { |
| // Get function info, elements are partially sorted (it is a tree |
| // of nested functions serialized as parent followed by serialized children. |
| var raw_compile_info = %LiveEditGatherCompileInfo(script, source); |
| |
| // Sort function infos by start position field. |
| var compile_info = new Array(); |
| var old_index_map = new Array(); |
| for (var i = 0; i < raw_compile_info.length; i++) { |
| compile_info.push(new liveedit.FunctionCompileInfo(raw_compile_info[i])); |
| old_index_map.push(i); |
| } |
| |
| for (var i = 0; i < compile_info.length; i++) { |
| var k = i; |
| for (var j = i + 1; j < compile_info.length; j++) { |
| if (compile_info[k].start_position > compile_info[j].start_position) { |
| k = j; |
| } |
| } |
| if (k != i) { |
| var temp_info = compile_info[k]; |
| var temp_index = old_index_map[k]; |
| compile_info[k] = compile_info[i]; |
| old_index_map[k] = old_index_map[i]; |
| compile_info[i] = temp_info; |
| old_index_map[i] = temp_index; |
| } |
| } |
| |
| // After sorting update outer_inder field using old_index_map. Also |
| // set next_sibling_index field. |
| var current_index = 0; |
| |
| // The recursive function, that goes over all children of a particular |
| // node (i.e. function info). |
| function ResetIndexes(new_parent_index, old_parent_index) { |
| var previous_sibling = -1; |
| while (current_index < compile_info.length && |
| compile_info[current_index].outer_index == old_parent_index) { |
| var saved_index = current_index; |
| compile_info[saved_index].outer_index = new_parent_index; |
| if (previous_sibling != -1) { |
| compile_info[previous_sibling].next_sibling_index = saved_index; |
| } |
| previous_sibling = saved_index; |
| current_index++; |
| ResetIndexes(saved_index, old_index_map[saved_index]); |
| } |
| if (previous_sibling != -1) { |
| compile_info[previous_sibling].next_sibling_index = -1; |
| } |
| } |
| |
| ResetIndexes(-1, -1); |
| Assert(current_index == compile_info.length); |
| |
| return compile_info; |
| } |
| |
| // Given a positions, finds a function that fully includes the entire change. |
| function FindChangedFunction(compile_info, offset, len) { |
| // First condition: function should start before the change region. |
| // Function #0 (whole-script function) always does, but we want |
| // one, that is later in this list. |
| var index = 0; |
| while (index + 1 < compile_info.length && |
| compile_info[index + 1].start_position <= offset) { |
| index++; |
| } |
| // Now we are at the last function that begins before the change |
| // region. The function that covers entire change region is either |
| // this function or the enclosing one. |
| for (; compile_info[index].end_position < offset + len; |
| index = compile_info[index].outer_index) { |
| Assert(index != -1); |
| } |
| return index; |
| } |
| |
| // Variable forward declarations. Preprocessor "Minifier" needs them. |
| var old_compile_info; |
| var shared_infos; |
| // Finds SharedFunctionInfo that corresponds compile info with index |
| // in old version of the script. |
| function FindFunctionInfo(index) { |
| var old_info = old_compile_info[index]; |
| for (var i = 0; i < shared_infos.length; i++) { |
| var info = shared_infos[i]; |
| if (info.start_position == old_info.start_position && |
| info.end_position == old_info.end_position) { |
| return info; |
| } |
| } |
| } |
| |
| // Replaces function's Code. |
| function PatchCode(new_info, shared_info) { |
| %LiveEditReplaceFunctionCode(new_info.raw_array, shared_info.raw_array); |
| |
| change_log.push( {function_patched: new_info.function_name} ); |
| } |
| |
| var change_len_old; |
| var change_len_new; |
| // Translate position in old version of script into position in new |
| // version of script. |
| function PosTranslator(old_pos) { |
| if (old_pos <= change_pos) { |
| return old_pos; |
| } |
| if (old_pos >= change_pos + change_len_old) { |
| return old_pos + change_len_new - change_len_old; |
| } |
| return -1; |
| } |
| |
| var position_change_array; |
| var position_patch_report; |
| function PatchPositions(new_info, shared_info) { |
| if (!shared_info) { |
| // TODO: explain what is happening. |
| return; |
| } |
| %LiveEditPatchFunctionPositions(shared_info.raw_array, |
| position_change_array); |
| position_patch_report.push( { name: new_info.function_name } ); |
| } |
| |
| var link_to_old_script_report; |
| var old_script; |
| // Makes a function associated with another instance of a script (the |
| // one representing its old version). This way the function still |
| // may access its own text. |
| function LinkToOldScript(shared_info) { |
| %LiveEditRelinkFunctionToScript(shared_info.raw_array, old_script); |
| |
| link_to_old_script_report.push( { name: shared_info.function_name } ); |
| } |
| |
| |
| |
| var old_source = script.source; |
| var change_len_old = change_len; |
| var change_len_new = new_str.length; |
| |
| // Prepare new source string. |
| var new_source = old_source.substring(0, change_pos) + |
| new_str + old_source.substring(change_pos + change_len); |
| |
| // Find all SharedFunctionInfo's that are compiled from this script. |
| var shared_raw_list = %LiveEditFindSharedFunctionInfosForScript(script); |
| |
| var shared_infos = new Array(); |
| |
| for (var i = 0; i < shared_raw_list.length; i++) { |
| shared_infos.push(new liveedit.SharedInfoWrapper(shared_raw_list[i])); |
| } |
| |
| // Gather compile information about old version of script. |
| var old_compile_info = DebugGatherCompileInfo(old_source); |
| |
| // Gather compile information about new version of script. |
| var new_compile_info; |
| try { |
| new_compile_info = DebugGatherCompileInfo(new_source); |
| } catch (e) { |
| throw new liveedit.Failure("Failed to compile new version of script: " + e); |
| } |
| |
| // An index of a single function, that is going to have its code replaced. |
| var function_being_patched = |
| FindChangedFunction(old_compile_info, change_pos, change_len_old); |
| |
| // In old and new script versions function with a change should have the |
| // same indexes. |
| var function_being_patched2 = |
| FindChangedFunction(new_compile_info, change_pos, change_len_new); |
| Assert(function_being_patched == function_being_patched2, |
| "inconsistent old/new compile info"); |
| |
| // Check that function being patched has the same expectations in a new |
| // version. Otherwise we cannot safely patch its behavior and should |
| // choose the outer function instead. |
| while (!liveedit.CompareFunctionExpectations( |
| old_compile_info[function_being_patched], |
| new_compile_info[function_being_patched])) { |
| |
| Assert(old_compile_info[function_being_patched].outer_index == |
| new_compile_info[function_being_patched].outer_index); |
| function_being_patched = |
| old_compile_info[function_being_patched].outer_index; |
| Assert(function_being_patched != -1); |
| } |
| |
| // Check that function being patched is not currently on stack. |
| liveedit.CheckStackActivations( |
| [ FindFunctionInfo(function_being_patched) ], change_log ); |
| |
| |
| // Committing all changes. |
| var old_script_name = liveedit.CreateNameForOldScript(script); |
| |
| // Update the script text and create a new script representing an old |
| // version of the script. |
| var old_script = %LiveEditReplaceScript(script, new_source, old_script_name); |
| |
| PatchCode(new_compile_info[function_being_patched], |
| FindFunctionInfo(function_being_patched)); |
| |
| var position_patch_report = new Array(); |
| change_log.push( {position_patched: position_patch_report} ); |
| |
| var position_change_array = [ change_pos, |
| change_pos + change_len_old, |
| change_pos + change_len_new ]; |
| |
| // Update positions of all outer functions (i.e. all functions, that |
| // are partially below the function being patched). |
| for (var i = new_compile_info[function_being_patched].outer_index; |
| i != -1; |
| i = new_compile_info[i].outer_index) { |
| PatchPositions(new_compile_info[i], FindFunctionInfo(i)); |
| } |
| |
| // Update positions of all functions that are fully below the function |
| // being patched. |
| var old_next_sibling = |
| old_compile_info[function_being_patched].next_sibling_index; |
| var new_next_sibling = |
| new_compile_info[function_being_patched].next_sibling_index; |
| |
| // We simply go over the tail of both old and new lists. Their tails should |
| // have an identical structure. |
| if (old_next_sibling == -1) { |
| Assert(new_next_sibling == -1); |
| } else { |
| Assert(old_compile_info.length - old_next_sibling == |
| new_compile_info.length - new_next_sibling); |
| |
| for (var i = old_next_sibling, j = new_next_sibling; |
| i < old_compile_info.length; i++, j++) { |
| PatchPositions(new_compile_info[j], FindFunctionInfo(i)); |
| } |
| } |
| |
| var link_to_old_script_report = new Array(); |
| change_log.push( { linked_to_old_script: link_to_old_script_report } ); |
| |
| // We need to link to old script all former nested functions. |
| for (var i = function_being_patched + 1; i < old_next_sibling; i++) { |
| LinkToOldScript(FindFunctionInfo(i), old_script); |
| } |
| } |
| |
| Debug.LiveEditChangeScript.Assert = function(condition, message) { |
| if (!condition) { |
| if (message) { |
| throw "Assert " + message; |
| } else { |
| throw "Assert"; |
| } |
| } |
| } |
| |
| // An object describing function compilation details. Its index fields |
| // apply to indexes inside array that stores these objects. |
| Debug.LiveEditChangeScript.FunctionCompileInfo = function(raw_array) { |
| this.function_name = raw_array[0]; |
| this.start_position = raw_array[1]; |
| this.end_position = raw_array[2]; |
| this.param_num = raw_array[3]; |
| this.code = raw_array[4]; |
| this.scope_info = raw_array[5]; |
| this.outer_index = raw_array[6]; |
| this.next_sibling_index = null; |
| this.raw_array = raw_array; |
| } |
| |
| // A structure describing SharedFunctionInfo. |
| Debug.LiveEditChangeScript.SharedInfoWrapper = function(raw_array) { |
| this.function_name = raw_array[0]; |
| this.start_position = raw_array[1]; |
| this.end_position = raw_array[2]; |
| this.info = raw_array[3]; |
| this.raw_array = raw_array; |
| } |
| |
| // Adds a suffix to script name to mark that it is old version. |
| Debug.LiveEditChangeScript.CreateNameForOldScript = function(script) { |
| // TODO(635): try better than this; support several changes. |
| return script.name + " (old)"; |
| } |
| |
| // Compares a function interface old and new version, whether it |
| // changed or not. |
| Debug.LiveEditChangeScript.CompareFunctionExpectations = |
| function(function_info1, function_info2) { |
| // Check that function has the same number of parameters (there may exist |
| // an adapter, that won't survive function parameter number change). |
| if (function_info1.param_num != function_info2.param_num) { |
| return false; |
| } |
| var scope_info1 = function_info1.scope_info; |
| var scope_info2 = function_info2.scope_info; |
| |
| if (!scope_info1) { |
| return !scope_info2; |
| } |
| |
| if (scope_info1.length != scope_info2.length) { |
| return false; |
| } |
| |
| // Check that outer scope structure is not changed. Otherwise the function |
| // will not properly work with existing scopes. |
| return scope_info1.toString() == scope_info2.toString(); |
| } |
| |
| // For array of wrapped shared function infos checks that none of them |
| // have activations on stack (of any thread). Throws a Failure exception |
| // if this proves to be false. |
| Debug.LiveEditChangeScript.CheckStackActivations = function(shared_wrapper_list, |
| change_log) { |
| var liveedit = Debug.LiveEditChangeScript; |
| |
| var shared_list = new Array(); |
| for (var i = 0; i < shared_wrapper_list.length; i++) { |
| shared_list[i] = shared_wrapper_list[i].info; |
| } |
| var result = %LiveEditCheckStackActivations(shared_list); |
| var problems = new Array(); |
| for (var i = 0; i < shared_list.length; i++) { |
| if (result[i] == liveedit.FunctionPatchabilityStatus.FUNCTION_BLOCKED_ON_STACK) { |
| var shared = shared_list[i]; |
| var description = { |
| name: shared.function_name, |
| start_pos: shared.start_position, |
| end_pos: shared.end_position |
| }; |
| problems.push(description); |
| } |
| } |
| if (problems.length > 0) { |
| change_log.push( { functions_on_stack: problems } ); |
| throw new liveedit.Failure("Blocked by functions on stack"); |
| } |
| } |
| |
| // A copy of the FunctionPatchabilityStatus enum from liveedit.h |
| Debug.LiveEditChangeScript.FunctionPatchabilityStatus = { |
| FUNCTION_AVAILABLE_FOR_PATCH: 0, |
| FUNCTION_BLOCKED_ON_STACK: 1 |
| } |
| |
| |
| // A logical failure in liveedit process. This means that change_log |
| // is valid and consistent description of what happened. |
| Debug.LiveEditChangeScript.Failure = function(message) { |
| this.message = message; |
| } |
| |
| Debug.LiveEditChangeScript.Failure.prototype.toString = function() { |
| return "LiveEdit Failure: " + this.message; |
| } |