2010-10-26 12:00:54 -07:00
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/* -*- Mode: c++; c-basic-offset: 4; tab-width: 40; indent-tabs-mode: nil -*- */
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/* vim: set ts=40 sw=4 et tw=99: */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the Mozilla SpiderMonkey bytecode analysis
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*
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* The Initial Developer of the Original Code is
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* Mozilla Foundation
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* Portions created by the Initial Developer are Copyright (C) 2010
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* Definitions for javascript analysis. */
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#ifndef jsanalyze_h___
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#define jsanalyze_h___
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#include "jsarena.h"
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#include "jscntxt.h"
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#include "jsinfer.h"
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#include "jsscript.h"
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struct JSScript;
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namespace js {
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namespace analyze {
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class Script;
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/* Information about a bytecode instruction. */
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struct Bytecode
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{
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friend class Script;
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/* Whether there are any incoming jumps to this instruction. */
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bool jumpTarget : 1;
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/* Whether this instruction has been analyzed to get its output defines and stack. */
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bool analyzed : 1;
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/* Whether this is a catch/finally entry point. */
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bool exceptionEntry : 1;
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/* Whether this is in a try block. */
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bool inTryBlock : 1;
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/* Whether this is a method JIT safe point. */
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bool safePoint : 1;
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/* Stack depth before this opcode. */
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uint32 stackDepth;
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/*
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* The set of locals defined at this point. This does not include locals which
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* were unconditionally defined at an earlier point in the script.
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*/
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uint32 defineCount;
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uint32 *defineArray;
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Bytecode(Script *script, unsigned offset)
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{
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PodZero(this);
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#ifdef JS_TYPE_INFERENCE
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this->script = script;
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this->offset = offset;
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#endif
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}
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private:
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bool mergeDefines(JSContext *cx, Script *script, bool initial,
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uint32 newDepth, types::TypeStack *newStack,
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uint32 *newArray, uint32 newCount);
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/* Whether a local variable is in the define set at this bytecode. */
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bool isDefined(uint32 slot)
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{
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JS_ASSERT(analyzed);
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for (unsigned ind = 0; ind < defineCount; ind++) {
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if (defineArray[ind] == slot)
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return true;
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}
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return false;
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}
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#ifdef JS_TYPE_INFERENCE
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public:
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Script *script;
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unsigned offset;
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/* Contents of the stack when this instruction is executed. */
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types::TypeStack *inStack;
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/* Array of stack nodes pushed by this instruction. */
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types::TypeStack *pushedArray;
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/* Any new object created at this bytecode. */
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types::TypeObject *initObject;
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/* Whether this bytecode needs to have its effects monitored dynamically. */
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bool monitorNeeded;
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/*
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* For logging, whether we've generated warnings due to a mismatch between the
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* actual and inferred types at this bytecode.
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*/
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bool missingTypes;
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/* Pool which constraints on this instruction should use. */
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inline JSArenaPool &pool();
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/* Get the type set for the Nth value popped by this instruction. */
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inline types::TypeSet *popped(unsigned num);
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/* Get the type set for the Nth value pushed by this instruction. */
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inline types::TypeSet *pushed(unsigned num);
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/* Mark a trivially determined fixed type for a value pushed by this instruction. */
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inline void setFixed(JSContext *cx, unsigned num, types::jstype type);
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/*
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* Get the new object at this bytecode. propagation will be performed from
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* either Object or Array, per isArray.
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*/
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inline types::TypeObject* getInitObject(JSContext *cx, bool isArray);
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/*
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* Get the type tag which values in this set must have, or JSVAL_TYPE_UNKNOWN
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* if the type tag is not known.
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*/
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inline JSValueType getKnownTypeTag();
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void print(JSContext *cx, FILE *out);
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#endif /* JS_TYPE_INFERENCE */
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};
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/* Information about a script. */
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class Script
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{
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friend struct Bytecode;
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JSScript *script;
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Bytecode **codeArray;
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/* Maximum number of locals to consider for a script. */
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static const unsigned LOCAL_LIMIT = 50;
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/* Offsets at which each local becomes unconditionally defined, or a value below. */
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uint32 *locals;
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static const uint32 LOCAL_USE_BEFORE_DEF = uint32(-1);
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static const uint32 LOCAL_CONDITIONALLY_DEFINED = uint32(-2);
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bool outOfMemory;
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bool hadFailure;
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bool usesRval;
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bool usesScope;
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public:
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/* Pool for allocating analysis structures which will not outlive this script. */
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JSArenaPool pool;
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void init(JSScript *script);
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void analyze(JSContext *cx);
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void destroy();
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/*
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* For analysis scripts allocated on the stack. Scripts don't have constructors,
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* and must be zeroed out before being used.
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*/
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~Script() { destroy(); }
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/* Whether we ran out of memory during analysis. */
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bool OOM() { return outOfMemory; }
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/* Whether the script was analyzed successfully. */
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bool failed() { return hadFailure; }
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/* Whether there are POPV/SETRVAL bytecodes which can write to the frame's rval. */
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bool usesReturnValue() const { return usesRval; }
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/* Whether there are NAME bytecodes which can access the frame's scope chain. */
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bool usesScopeChain() const { return usesScope; }
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/* Whether the script has been analyzed. */
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bool hasAnalyzed() const { return !!codeArray; }
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/* Script being analyzed. */
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JSScript *getScript() const { return script; }
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/* Accessors for bytecode information. */
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Bytecode& getCode(uint32 offset) {
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JS_ASSERT(offset < script->length);
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JS_ASSERT(codeArray[offset]);
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return *codeArray[offset];
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}
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Bytecode& getCode(const jsbytecode *pc) { return getCode(pc - script->code); }
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Bytecode* maybeCode(uint32 offset) {
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JS_ASSERT(offset < script->length);
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return codeArray[offset];
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}
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Bytecode* maybeCode(const jsbytecode *pc) { return maybeCode(pc - script->code); }
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bool jumpTarget(uint32 offset) {
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JS_ASSERT(offset < script->length);
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return codeArray[offset] && codeArray[offset]->jumpTarget;
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}
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bool jumpTarget(const jsbytecode *pc) { return jumpTarget(pc - script->code); }
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/* Accessors for local variable information. */
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unsigned localCount() {
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return (script->nfixed >= LOCAL_LIMIT) ? LOCAL_LIMIT : script->nfixed;
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}
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bool localHasUseBeforeDef(uint32 local) {
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JS_ASSERT(!failed());
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return local >= localCount() || locals[local] == LOCAL_USE_BEFORE_DEF;
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}
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/* These return true for variables that may have a use before def. */
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bool localDefined(uint32 local, uint32 offset) {
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return localHasUseBeforeDef(local) || (locals[local] <= offset) ||
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getCode(offset).isDefined(local);
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}
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bool localDefined(uint32 local, jsbytecode *pc) {
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return localDefined(local, pc - script->code);
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}
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private:
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void setOOM(JSContext *cx) {
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if (!outOfMemory)
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js_ReportOutOfMemory(cx);
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outOfMemory = true;
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hadFailure = true;
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}
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inline bool addJump(JSContext *cx, unsigned offset,
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unsigned *currentOffset, unsigned *forwardJump,
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unsigned stackDepth, types::TypeStack *stack,
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uint32 *defineArray, unsigned defineCount);
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inline void setLocal(uint32 local, uint32 offset);
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#ifdef JS_TYPE_INFERENCE
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public:
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/* Unique identifier within the compartment. */
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unsigned id;
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/* Function this script is the body for, if there is one. */
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types::TypeFunction *function;
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/* Argument count and name from the function. */
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unsigned argCount;
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jsid thisName;
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/* List of objects associated with this script. */
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types::TypeObject *objects;
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/*
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* Location where the definition of this script occurs, representing any
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* nesting for scope lookups. NULL for global scripts.
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*/
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JSScript *parent;
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const jsbytecode *parentpc;
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/*
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* Variables defined by this script. This includes local variables defined
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* with 'var' or 'let', formal arguments, unnamed arguments, and properties
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* of the script itself (*not* properties of the script's prototype).
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*/
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types::VariableSet localTypes;
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/* Types of the 'this' variable in this script. */
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types::TypeSet thisTypes;
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/* Array of local variable names, computed by js_GetLocalNameArray. */
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jsuword *localNames;
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void setFunction(JSContext *cx, JSFunction *fun);
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inline bool isEval() { return parent && !function; }
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/*
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* Get the non-eval script which this one is nested in, returning this script
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* if it was not produced as the result of an eval.
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*/
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inline Script *evalParent();
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/* Bytecode where this script is nested. */
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inline Bytecode *parentCode();
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void print(JSContext *cx);
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/* Helpers */
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/* Temporary state for handling opcodes with fused behavior. */
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struct TypeState {
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/* Last opcode was JSOP_GETTER or JSOP_SETTER. */
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bool hasGetSet;
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TypeState()
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: hasGetSet(false)
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{}
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};
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/* Analyzes a bytecode, generating type constraints describing its behavior. */
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void analyzeTypes(JSContext *cx, Bytecode *codeType, TypeState &state);
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/*
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* Get the name to use for the local with specified index. Stack indicates the
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* point of the access, for looking up let variables.
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*/
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inline jsid getLocalId(unsigned index, types::TypeStack *stack);
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/* Get the name to use for the argument with the specified index. */
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inline jsid getArgumentId(unsigned index);
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/* Get the type set to use for a stack slot at a fixed stack depth. */
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inline types::TypeSet *getStackTypes(unsigned index, types::TypeStack *stack);
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#endif /* JS_TYPE_INFERENCE */
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};
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static inline unsigned
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GetBytecodeLength(jsbytecode *pc)
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{
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JSOp op = (JSOp)*pc;
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JS_ASSERT(op < JSOP_LIMIT);
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JS_ASSERT(op != JSOP_TRAP);
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|
|
if (js_CodeSpec[op].length != -1)
|
|
|
|
return js_CodeSpec[op].length;
|
|
|
|
return js_GetVariableBytecodeLength(pc);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline unsigned
|
|
|
|
GetUseCount(JSScript *script, unsigned offset)
|
|
|
|
{
|
|
|
|
JS_ASSERT(offset < script->length);
|
|
|
|
jsbytecode *pc = script->code + offset;
|
|
|
|
if (js_CodeSpec[*pc].nuses == -1)
|
|
|
|
return js_GetVariableStackUses(JSOp(*pc), pc);
|
|
|
|
return js_CodeSpec[*pc].nuses;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline unsigned
|
|
|
|
GetDefCount(JSScript *script, unsigned offset)
|
|
|
|
{
|
|
|
|
JS_ASSERT(offset < script->length);
|
|
|
|
jsbytecode *pc = script->code + offset;
|
|
|
|
if (js_CodeSpec[*pc].ndefs == -1)
|
|
|
|
return js_GetEnterBlockStackDefs(NULL, script, pc);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Add an extra pushed value for OR/AND opcodes, so that they are included
|
|
|
|
* in the pushed array of stack values for type inference.
|
|
|
|
*/
|
|
|
|
switch (JSOp(*pc)) {
|
|
|
|
case JSOP_OR:
|
|
|
|
case JSOP_ORX:
|
|
|
|
case JSOP_AND:
|
|
|
|
case JSOP_ANDX:
|
|
|
|
return 1;
|
|
|
|
default:
|
|
|
|
return js_CodeSpec[*pc].ndefs;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-10-26 12:00:54 -07:00
|
|
|
} /* namespace analyze */
|
|
|
|
} /* namespace js */
|
|
|
|
|
|
|
|
#endif // jsanalyze_h___
|