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+/* -*- 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___
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