https://github.com/mozilla/gecko-dev
Tip revision: 776606f924168b74b3af23aa49f39369402f954f authored by ffxbld on 19 October 2011, 14:10:26 UTC
Added tag FENNEC_8_0b4_BUILD1 for changeset 85d90596cab0. CLOSED TREE a=release
Added tag FENNEC_8_0b4_BUILD1 for changeset 85d90596cab0. CLOSED TREE a=release
Tip revision: 776606f
jsanalyze.h
/* -*- Mode: c++; c-basic-offset: 4; tab-width: 40; indent-tabs-mode: nil -*- */
/* vim: set ts=40 sw=4 et tw=99: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Mozilla SpiderMonkey bytecode analysis
*
* The Initial Developer of the Original Code is
* Mozilla Foundation
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* Definitions for javascript analysis. */
#ifndef jsanalyze_h___
#define jsanalyze_h___
#include "jsarena.h"
#include "jscntxt.h"
#include "jsscript.h"
struct JSScript;
namespace js {
namespace analyze {
class Script;
/* Information about a bytecode instruction. */
struct Bytecode
{
friend class Script;
/* Whether there are any incoming jumps to this instruction. */
bool jumpTarget : 1;
/* Whether this instruction has been analyzed to get its output defines and stack. */
bool analyzed : 1;
/* Whether this is a catch/finally entry point. */
bool exceptionEntry : 1;
/* Whether this is in a try block. */
bool inTryBlock : 1;
/* Whether this is a method JIT safe point. */
bool safePoint : 1;
/* Stack depth before this opcode. */
uint32 stackDepth;
/*
* The set of locals defined at this point. This does not include locals which
* were unconditionally defined at an earlier point in the script.
*/
uint32 defineCount;
uint32 *defineArray;
Bytecode()
{
PodZero(this);
}
private:
bool mergeDefines(JSContext *cx,
Script *script, bool initial, uint32 newDepth,
uint32 *newArray, uint32 newCount);
/* Whether a local variable is in the define set at this bytecode. */
bool isDefined(uint32 slot)
{
JS_ASSERT(analyzed);
for (size_t ind = 0; ind < defineCount; ind++) {
if (defineArray[ind] == slot)
return true;
}
return false;
}
};
/* Information about a script. */
class Script
{
friend struct Bytecode;
JSScript *script;
Bytecode **code;
/* Maximum number of locals to consider for a script. */
static const unsigned LOCAL_LIMIT = 50;
/* Offsets at which each local becomes unconditionally defined, or a value below. */
uint32 *locals;
static const uint32 LOCAL_USE_BEFORE_DEF = uint32(-1);
static const uint32 LOCAL_CONDITIONALLY_DEFINED = uint32(-2);
bool outOfMemory;
bool hadFailure;
bool usesRval;
bool usesScope;
public:
/* Pool for allocating analysis structures which will not outlive this script. */
JSArenaPool pool;
void analyze(JSContext *cx, JSScript *script);
void destroy();
/*
* For analysis scripts allocated on the stack. Scripts don't have constructors,
* and must be zeroed out before being used.
*/
~Script() { destroy(); }
/* Whether we ran out of memory during analysis. */
bool OOM() { return outOfMemory; }
/* Whether the script was analyzed successfully. */
bool failed() { return hadFailure; }
/* Whether there are POPV/SETRVAL bytecodes which can write to the frame's rval. */
bool usesReturnValue() const { return usesRval; }
/* Whether there are NAME bytecodes which can access the frame's scope chain. */
bool usesScopeChain() const { return usesScope; }
/* Accessors for bytecode information. */
Bytecode& getCode(uint32 offset) {
JS_ASSERT(offset < script->length);
JS_ASSERT(code[offset]);
return *code[offset];
}
Bytecode& getCode(jsbytecode *pc) { return getCode(pc - script->code); }
Bytecode* maybeCode(uint32 offset) {
JS_ASSERT(offset < script->length);
return code[offset];
}
Bytecode* maybeCode(jsbytecode *pc) { return maybeCode(pc - script->code); }
bool jumpTarget(uint32 offset) {
JS_ASSERT(offset < script->length);
return code[offset] && code[offset]->jumpTarget;
}
bool jumpTarget(jsbytecode *pc) { return jumpTarget(pc - script->code); }
/* Accessors for local variable information. */
unsigned localCount() {
return (script->nfixed >= LOCAL_LIMIT) ? LOCAL_LIMIT : script->nfixed;
}
bool localHasUseBeforeDef(uint32 local) {
JS_ASSERT(local < script->nfixed && !failed());
return local >= localCount() || locals[local] == LOCAL_USE_BEFORE_DEF;
}
/* These return true for variables that may have a use before def. */
bool localDefined(uint32 local, uint32 offset) {
return localHasUseBeforeDef(local) || (locals[local] <= offset) ||
getCode(offset).isDefined(local);
}
bool localDefined(uint32 local, jsbytecode *pc) {
return localDefined(local, pc - script->code);
}
private:
void setOOM(JSContext *cx) {
if (!outOfMemory)
js_ReportOutOfMemory(cx);
outOfMemory = true;
hadFailure = true;
}
inline bool addJump(JSContext *cx, unsigned offset,
unsigned *currentOffset, unsigned *forwardJump,
unsigned stackDepth, uint32 *defineArray, unsigned defineCount);
inline void setLocal(uint32 local, uint32 offset);
};
} /* namespace analyze */
} /* namespace js */
#endif // jsanalyze_h___