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Bug 601256: optimize access to globals in global eval using GNAME ops, r=dvander

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--HG--
extra : rebase_source : 7c4bd486cc9dff1c65eda717fe34dd0fc36fe171
This commit is contained in:
David Mandelin 2010-10-05 11:02:05 -07:00
parent 547d789b0a
commit 693026324a
1 changed files with 51 additions and 24 deletions
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75
js/src/jsemit.cpp
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@ -2031,6 +2031,39 @@ MakeUpvarForEval(JSParseNode *pn, JSCodeGenerator *cg)
return true;
}
/*
* Try to convert a *NAME op to a *GNAME op, which optimizes access to
* undeclared globals. Return true if a conversion was made.
*
* This conversion is not made if we are in strict mode, because the
* access to an undeclared global would be an error.
*/
static bool
TryConvertToGname(JSCodeGenerator *cg, JSParseNode *pn, JSOp *op)
{
if (cg->compileAndGo() &&
cg->compiler()->globalScope->globalObj &&
!pn->isDeoptimized() &&
!(cg->flags & TCF_STRICT_MODE_CODE)) {
switch (*op) {
case JSOP_NAME: *op = JSOP_GETGNAME; break;
case JSOP_SETNAME: *op = JSOP_SETGNAME; break;
case JSOP_INCNAME: *op = JSOP_INCGNAME; break;
case JSOP_NAMEINC: *op = JSOP_GNAMEINC; break;
case JSOP_DECNAME: *op = JSOP_DECGNAME; break;
case JSOP_NAMEDEC: *op = JSOP_GNAMEDEC; break;
case JSOP_SETCONST:
case JSOP_DELNAME:
case JSOP_FORNAME:
/* Not supported. */
return false;
default: JS_NOT_REACHED("gname");
}
return true;
}
return false;
}
/*
* BindNameToSlot attempts to optimize name gets and sets to stack slot loads
* and stores, given the compile-time information in cg and a TOK_NAME node pn.
@ -2140,6 +2173,21 @@ BindNameToSlot(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
return JS_TRUE;
JS_ASSERT(caller->isScriptFrame());
/*
* If this is an eval in the global scope, then unbound variables
* must be globals, so try to use GNAME ops.
*/
if (caller->isGlobalFrame() && TryConvertToGname(cg, pn, &op)) {
ale = cg->atomList.add(cg->parser, atom);
if (!ale)
return JS_FALSE;
pn->pn_op = op;
pn->pn_dflags |= PND_BOUND;
return JS_TRUE;
}
if (!caller->isFunctionFrame())
return JS_TRUE;
@ -2178,30 +2226,9 @@ BindNameToSlot(JSContext *cx, JSCodeGenerator *cg, JSParseNode *pn)
return MakeUpvarForEval(pn, cg);
}
/*
* Optimize accesses to undeclared globals, but only if we are in
* compile-and-go mode, the global is the same as the scope chain,
* and we are not in strict mode.
*/
if (cg->compileAndGo() &&
cg->compiler()->globalScope->globalObj &&
!pn->isDeoptimized() &&
!(cg->flags & TCF_STRICT_MODE_CODE)) {
switch (op) {
case JSOP_NAME: op = JSOP_GETGNAME; break;
case JSOP_SETNAME: op = JSOP_SETGNAME; break;
case JSOP_INCNAME: op = JSOP_INCGNAME; break;
case JSOP_NAMEINC: op = JSOP_GNAMEINC; break;
case JSOP_DECNAME: op = JSOP_DECGNAME; break;
case JSOP_NAMEDEC: op = JSOP_GNAMEDEC; break;
case JSOP_SETCONST:
case JSOP_DELNAME:
case JSOP_FORNAME:
/* Not supported. */
return JS_TRUE;
default: JS_NOT_REACHED("gname");
}
}
/* Optimize accesses to undeclared globals. */
if (!TryConvertToGname(cg, pn, &op))
return JS_TRUE;
ale = cg->atomList.add(cg->parser, atom);
if (!ale)