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Bug 769041 - Remove the __proto__ special-casing from dotted property accesses; as tests demonstrate, it's unnecessary to pass tests, and for obvious reasons it doesn't need to be performant. r=luke

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This commit is contained in:
Jeff Walden 2012-06-27 14:03:49 -07:00
parent 98931d82a3
commit d29d223949
1 changed files with 6 additions and 37 deletions
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43
js/src/frontend/BytecodeEmitter.cpp
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@ -1711,26 +1711,6 @@ EmitElemOpBase(JSContext *cx, BytecodeEmitter *bce, JSOp op)
return true;
}
static bool
EmitSpecialPropOp(JSContext *cx, ParseNode *pn, JSOp op, BytecodeEmitter *bce)
{
/*
* Special case for obj.__proto__ to deoptimize away from fast paths in the
* interpreter and trace recorder, which skip dense array instances by
* going up to Array.prototype before looking up the property name.
*/
if (op == JSOP_CALLELEM && Emit1(cx, bce, JSOP_DUP) < 0)
return false;
jsatomid index;
if (!bce->makeAtomIndex(pn->pn_atom, &index))
return false;
if (!EmitIndex32(cx, JSOP_QNAMEPART, index, bce))
return false;
return EmitElemOpBase(cx, bce, op);
}
static bool
EmitPropOp(JSContext *cx, ParseNode *pn, JSOp op, BytecodeEmitter *bce,
JSBool callContext)
@ -1782,13 +1762,8 @@ EmitPropOp(JSContext *cx, ParseNode *pn, JSOp op, BytecodeEmitter *bce,
if (NewSrcNote2(cx, bce, SRC_PCBASE, bce->offset() - pndown->pn_offset) < 0)
return false;
/* Special case deoptimization on __proto__, as above. */
if (pndot->isArity(PN_NAME) && pndot->pn_atom == cx->runtime->atomState.protoAtom) {
if (!EmitSpecialPropOp(cx, pndot, JSOP_GETELEM, bce))
return false;
} else if (!EmitAtomOp(cx, pndot, pndot->getOp(), bce)) {
if (!EmitAtomOp(cx, pndot, pndot->getOp(), bce))
return false;
}
/* Reverse the pn_expr link again. */
pnup = pndot->pn_expr;
@ -3466,20 +3441,14 @@ EmitAssignment(JSContext *cx, BytecodeEmitter *bce, ParseNode *lhs, JSOp op, Par
return false;
}
break;
case PNK_DOT:
case PNK_DOT: {
if (Emit1(cx, bce, JSOP_DUP) < 0)
return false;
if (lhs->pn_atom == cx->runtime->atomState.protoAtom) {
if (!EmitIndex32(cx, JSOP_QNAMEPART, atomIndex, bce))
return false;
if (!EmitElemOpBase(cx, bce, JSOP_GETELEM))
return false;
} else {
bool isLength = (lhs->pn_atom == cx->runtime->atomState.lengthAtom);
if (!EmitIndex32(cx, isLength ? JSOP_LENGTH : JSOP_GETPROP, atomIndex, bce))
return false;
}
bool isLength = (lhs->pn_atom == cx->runtime->atomState.lengthAtom);
if (!EmitIndex32(cx, isLength ? JSOP_LENGTH : JSOP_GETPROP, atomIndex, bce))
return false;
break;
}
case PNK_LB:
case PNK_LP:
#if JS_HAS_XML_SUPPORT