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Bug 1204028: Evaluate LHS reference before RHS in destructuring

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Issue #73
[Depends on] Bug 1147371: Implement IteratorClose
This commit is contained in:
janekptacijarabaci 2018-03-20 12:40:00 +01:00 • committed by Roy Tam
commit 2f27d8433c
11 changed files with 1743 additions and 97 deletions
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277
js/src/frontend/BytecodeEmitter.cpp
View file

@ -4325,7 +4325,69 @@ BytecodeEmitter::emitDestructuringDeclsWithEmitter(ParseNode* pattern, NameEmitt
}
bool
BytecodeEmitter::emitDestructuringLHS(ParseNode* target, DestructuringFlavor flav)
BytecodeEmitter::emitDestructuringLHSRef(ParseNode* target, size_t* emitted)
{
*emitted = 0;
if (target->isKind(PNK_SPREAD))
target = target->pn_kid;
else if (target->isKind(PNK_ASSIGN))
target = target->pn_left;
// No need to recur into PNK_ARRAY and PNK_OBJECT subpatterns here, since
// emitSetOrInitializeDestructuring does the recursion when setting or
// initializing value. Getting reference doesn't recur.
if (target->isKind(PNK_NAME) || target->isKind(PNK_ARRAY) || target->isKind(PNK_OBJECT))
return true;
#ifdef DEBUG
int depth = stackDepth;
#endif
switch (target->getKind()) {
case PNK_DOT: {
if (target->as<PropertyAccess>().isSuper()) {
if (!emitSuperPropLHS(&target->as<PropertyAccess>().expression()))
return false;
*emitted = 2;
} else {
if (!emitTree(target->pn_expr))
return false;
*emitted = 1;
}
break;
}
case PNK_ELEM: {
if (target->as<PropertyByValue>().isSuper()) {
if (!emitSuperElemOperands(target, EmitElemOption::Ref))
return false;
*emitted = 3;
} else {
if (!emitElemOperands(target, EmitElemOption::Ref))
return false;
*emitted = 2;
}
break;
}
case PNK_CALL:
MOZ_ASSERT_UNREACHABLE("Parser::reportIfNotValidSimpleAssignmentTarget "
"rejects function calls as assignment "
"targets in destructuring assignments");
break;
default:
MOZ_CRASH("emitDestructuringLHSRef: bad lhs kind");
}
MOZ_ASSERT(stackDepth == depth + int(*emitted));
return true;
}
bool
BytecodeEmitter::emitSetOrInitializeDestructuring(ParseNode* target, DestructuringFlavor flav)
{
// Now emit the lvalue opcode sequence. If the lvalue is a nested
// destructuring initialiser-form, call ourselves to handle it, then pop
@ -4401,44 +4463,28 @@ BytecodeEmitter::emitDestructuringLHS(ParseNode* target, DestructuringFlavor fla
}
case PNK_DOT: {
// See the (PNK_NAME, JSOP_SETNAME) case above.
//
// In `a.x = b`, `a` is evaluated first, then `b`, then a
// JSOP_SETPROP instruction.
//
// In `[a.x] = [b]`, per spec, `b` is evaluated before `a`. Then we
// need a property set -- but the operands are on the stack in the
// wrong order for JSOP_SETPROP, so we have to add a JSOP_SWAP.
// The reference is already pushed by emitDestructuringLHSRef.
JSOp setOp;
if (target->as<PropertyAccess>().isSuper()) {
if (!emitSuperPropLHS(&target->as<PropertyAccess>().expression()))
return false;
if (!emit2(JSOP_PICK, 2))
return false;
if (target->as<PropertyAccess>().isSuper())
setOp = sc->strict() ? JSOP_STRICTSETPROP_SUPER : JSOP_SETPROP_SUPER;
} else {
if (!emitTree(target->pn_expr))
return false;
if (!emit1(JSOP_SWAP))
return false;
else
setOp = sc->strict() ? JSOP_STRICTSETPROP : JSOP_SETPROP;
}
if (!emitAtomOp(target, setOp))
return false;
break;
}
case PNK_ELEM: {
// See the comment at `case PNK_DOT:` above. This case,
// `[a[x]] = [b]`, is handled much the same way. The JSOP_SWAP
// is emitted by emitElemOperands.
// The reference is already pushed by emitDestructuringLHSRef.
if (target->as<PropertyByValue>().isSuper()) {
JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM_SUPER : JSOP_SETELEM_SUPER;
if (!emitSuperElemOp(target, setOp))
// emitDestructuringLHSRef already did emitSuperElemOperands
// part of emitSuperElemOp. Perform remaining part here.
if (!emitElemOpBase(setOp))
return false;
} else {
JSOp setOp = sc->strict() ? JSOP_STRICTSETELEM : JSOP_SETELEM;
if (!emitElemOp(target, setOp))
if (!emitElemOpBase(setOp))
return false;
}
break;
@ -4451,7 +4497,7 @@ BytecodeEmitter::emitDestructuringLHS(ParseNode* target, DestructuringFlavor fla
break;
default:
MOZ_CRASH("emitDestructuringLHS: bad lhs kind");
MOZ_CRASH("emitSetOrInitializeDestructuring: bad lhs kind");
}
// Pop the assigned value.
@ -4732,11 +4778,13 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
//
// let x, y;
// let a, b, c, d;
// let iter, result, done, value; // stack values
// let iter, lref, result, done, value; // stack values
//
// iter = x[Symbol.iterator]();
//
// // ==== emitted by loop for a ====
// lref = GetReference(a);
//
// result = iter.next();
// done = result.done;
//
@ -4745,9 +4793,11 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// else
// value = result.value;
//
// a = value;
// SetOrInitialize(lref, value);
//
// // ==== emitted by loop for b ====
// lref = GetReference(b);
//
// if (done) {
// value = undefined;
// } else {
@ -4759,7 +4809,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// value = result.value;
// }
//
// b = value;
// SetOrInitialize(lref, value);
//
// // ==== emitted by loop for elision ====
// if (done) {
@ -4774,6 +4824,8 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// }
//
// // ==== emitted by loop for c ====
// lref = GetReference(c);
//
// if (done) {
// value = undefined;
// } else {
@ -4788,15 +4840,17 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// if (value === undefined)
// value = y;
//
// c = value;
// SetOrInitialize(lref, value);
//
// // ==== emitted by loop for d ====
// lref = GetReference(d);
//
// if (done)
// value = [];
// else
// value = [...iter];
//
// d = value;
// SetOrInitialize(lref, value);
// Use an iterator to destructure the RHS, instead of index lookup. We
// must leave the *original* value on the stack.
@ -4810,31 +4864,40 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
bool hasNext = !!member->pn_next;
if (member->isKind(PNK_SPREAD)) {
size_t emitted = 0;
if (!emitDestructuringLHSRef(member, &emitted)) // ... OBJ ITER ?DONE *LREF
return false;
IfThenElseEmitter ifThenElse(this);
if (!isHead) {
// If spread is not the first element of the pattern,
// iterator can already be completed.
// ... OBJ ITER DONE
if (!ifThenElse.emitIfElse()) // ... OBJ ITER
// ... OBJ ITER DONE *LREF
if (emitted) {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
if (!ifThenElse.emitIfElse()) // ... OBJ ITER *LREF
return false;
if (!emitUint32Operand(JSOP_NEWARRAY, 0)) // ... OBJ ITER ARRAY
if (!emitUint32Operand(JSOP_NEWARRAY, 0)) // ... OBJ ITER *LREF ARRAY
return false;
if (!ifThenElse.emitElse()) // ... OBJ ITER
if (!ifThenElse.emitElse()) // ... OBJ ITER *LREF
return false;
}
// If iterator is not completed, create a new array with the rest
// of the iterator.
if (!emit1(JSOP_DUP)) // ... OBJ ITER
if (!emitDupAt(emitted)) // ... OBJ ITER *LREF ITER
return false;
if (!emitUint32Operand(JSOP_NEWARRAY, 0)) // ... OBJ ITER ITER ARRAY
if (!emitUint32Operand(JSOP_NEWARRAY, 0)) // ... OBJ ITER *LREF ITER ARRAY
return false;
if (!emitNumberOp(0)) // ... OBJ ITER ITER ARRAY INDEX
if (!emitNumberOp(0)) // ... OBJ ITER *LREF ITER ARRAY INDEX
return false;
if (!emitSpread()) // ... OBJ ITER ARRAY INDEX
if (!emitSpread()) // ... OBJ ITER *LREF ARRAY INDEX
return false;
if (!emit1(JSOP_POP)) // ... OBJ ITER ARRAY
if (!emit1(JSOP_POP)) // ... OBJ ITER *LREF ARRAY
return false;
if (!isHead) {
@ -4843,7 +4906,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
MOZ_ASSERT(ifThenElse.pushed() == 1);
}
if (!emitDestructuringLHS(member, flav)) // ... OBJ ITER
if (!emitSetOrInitializeDestructuring(member, flav)) // ... OBJ ITER
return false;
MOZ_ASSERT(!hasNext);
@ -4861,69 +4924,91 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
MOZ_ASSERT(!subpattern->isKind(PNK_SPREAD));
size_t emitted = 0;
if (!isElision) {
if (!emitDestructuringLHSRef(subpattern, &emitted)) // ... OBJ ITER ?DONE *LREF
return false;
}
IfThenElseEmitter ifAlreadyDone(this);
if (!isHead) {
// If this element is not the first element of the pattern,
// iterator can already be completed.
// ... OBJ ITER DONE
if (hasNext) {
if (!emit1(JSOP_DUP)) // ... OBJ ITER DONE DONE
return false;
// ... OBJ ITER DONE *LREF
if (emitted) {
if (hasNext) {
if (!emitDupAt(emitted)) // ... OBJ ITER DONE *LREF DONE
return false;
} else {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
} else {
if (hasNext) {
// The position of LREF in the following stack comment
// isn't accurate for the operation, but it's equivalent
// since LREF is nothing
if (!emit1(JSOP_DUP)) // ... OBJ ITER DONE *LREF DONE
return false;
}
}
if (!ifAlreadyDone.emitIfElse()) // ... OBJ ITER ?DONE
if (!ifAlreadyDone.emitIfElse()) // ... OBJ ITER ?DONE *LREF
return false;
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE UNDEF
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE *LREF UNDEF
return false;
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE UNDEF
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE *LREF UNDEF
return false;
if (!ifAlreadyDone.emitElse()) // ... OBJ ITER ?DONE
if (!ifAlreadyDone.emitElse()) // ... OBJ ITER ?DONE *LREF
return false;
if (hasNext) {
if (!emit1(JSOP_POP)) // ... OBJ ITER
if (emitted) {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
if (!emit1(JSOP_POP)) // ... OBJ ITER *LREF
return false;
}
}
if (!emit1(JSOP_DUP)) // ... OBJ ITER ITER
if (emitted) {
if (!emitDupAt(emitted)) // ... OBJ ITER *LREF ITER
return false;
} else {
if (!emit1(JSOP_DUP)) // ... OBJ ITER *LREF ITER
return false;
}
if (!emitIteratorNext(pattern)) // ... OBJ ITER *LREF RESULT
return false;
if (!emitIteratorNext(pattern)) // ... OBJ ITER RESULT
if (!emit1(JSOP_DUP)) // ... OBJ ITER *LREF RESULT RESULT
return false;
if (!emit1(JSOP_DUP)) // ... OBJ ITER RESULT RESULT
return false;
if (!emitAtomOp(cx->names().done, JSOP_GETPROP)) // ... OBJ ITER RESULT DONE
if (!emitAtomOp(cx->names().done, JSOP_GETPROP)) // ... OBJ ITER *LREF RESULT DONE
return false;
if (hasNext) {
if (!emit1(JSOP_DUP)) // ... OBJ ITER RESULT DONE DONE
if (!emit1(JSOP_DUP)) // ... OBJ ITER *LREF RESULT DONE DONE
return false;
if (!emit2(JSOP_UNPICK, emitted + 2)) // ... OBJ ITER DONE *LREF RESULT DONE
return false;
}
IfThenElseEmitter ifDone(this);
if (!ifDone.emitIfElse()) // ... OBJ ITER RESULT ?DONE
if (!ifDone.emitIfElse()) // ... OBJ ITER ?DONE *LREF RESULT
return false;
if (hasNext) {
if (!emit1(JSOP_SWAP)) // ... OBJ ITER ?DONE RESULT
return false;
}
if (!emit1(JSOP_POP)) // ... OBJ ITER ?DONE
if (!emit1(JSOP_POP)) // ... OBJ ITER ?DONE *LREF
return false;
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE UNDEF
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE *LREF UNDEF
return false;
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE UNDEF
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE *LREF UNDEF
return false;
if (!ifDone.emitElse()) // ... OBJ ITER RESULT ?DONE
if (!ifDone.emitElse()) // ... OBJ ITER ?DONE *LREF RESULT
return false;
if (hasNext) {
if (!emit1(JSOP_SWAP)) // ... OBJ ITER ?DONE RESULT
return false;
}
if (!emitAtomOp(cx->names().value, JSOP_GETPROP)) // ... OBJ ITER ?DONE VALUE
if (!emitAtomOp(cx->names().value, JSOP_GETPROP)) // ... OBJ ITER ?DONE *LREF VALUE
return false;
if (!ifDone.emitEnd())
@ -4937,13 +5022,16 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
}
if (pndefault) {
if (!emitDefault(pndefault, subpattern)) // ... OBJ ITER ?DONE VALUE
if (!emitDefault(pndefault, subpattern)) // ... OBJ ITER ?DONE *LREF VALUE
return false;
}
if (!isElision) {
if (!emitDestructuringLHS(subpattern, flav)) // ... OBJ ITER ?DONE
if (!emitSetOrInitializeDestructuring(subpattern,
flav)) // ... OBJ ITER ?DONE
{
return false;
}
} else {
if (!emit1(JSOP_POP)) // ... OBJ ITER ?DONE
return false;
@ -4975,27 +5063,43 @@ BytecodeEmitter::emitDestructuringOpsObject(ParseNode* pattern, DestructuringFla
return false;
for (ParseNode* member = pattern->pn_head; member; member = member->pn_next) {
// Duplicate the value being destructured to use as a reference base.
if (!emit1(JSOP_DUP)) // ... RHS RHS
ParseNode* subpattern;
if (member->isKind(PNK_MUTATEPROTO))
subpattern = member->pn_kid;
else
subpattern = member->pn_right;
ParseNode* lhs = subpattern;
if (lhs->isKind(PNK_ASSIGN))
lhs = lhs->pn_left;
size_t emitted;
if (!emitDestructuringLHSRef(lhs, &emitted)) // ... RHS *LREF
return false;
// Duplicate the value being destructured to use as a reference base.
if (emitted) {
if (!emitDupAt(emitted)) // ... RHS *LREF RHS
return false;
} else {
if (!emit1(JSOP_DUP)) // ... RHS RHS
return false;
}
// Now push the property name currently being matched, which is the
// current property name "label" on the left of a colon in the object
// initialiser.
bool needsGetElem = true;
ParseNode* subpattern;
if (member->isKind(PNK_MUTATEPROTO)) {
if (!emitAtomOp(cx->names().proto, JSOP_GETPROP)) // ... RHS PROP
if (!emitAtomOp(cx->names().proto, JSOP_GETPROP)) // ... RHS *LREF PROP
return false;
needsGetElem = false;
subpattern = member->pn_kid;
} else {
MOZ_ASSERT(member->isKind(PNK_COLON) || member->isKind(PNK_SHORTHAND));
ParseNode* key = member->pn_left;
if (key->isKind(PNK_NUMBER)) {
if (!emitNumberOp(key->pn_dval)) // ... RHS RHS KEY
if (!emitNumberOp(key->pn_dval)) // ... RHS *LREF RHS KEY
return false;
} else if (key->isKind(PNK_OBJECT_PROPERTY_NAME) || key->isKind(PNK_STRING)) {
PropertyName* name = key->pn_atom->asPropertyName();
@ -5005,33 +5109,30 @@ BytecodeEmitter::emitDestructuringOpsObject(ParseNode* pattern, DestructuringFla
// as indexes for simplification of downstream analysis.
jsid id = NameToId(name);
if (id != IdToTypeId(id)) {
if (!emitTree(key)) // ... RHS RHS KEY
if (!emitTree(key)) // ... RHS *LREF RHS KEY
return false;
} else {
if (!emitAtomOp(name, JSOP_GETPROP)) // ...RHS PROP
if (!emitAtomOp(name, JSOP_GETPROP)) // ... RHS *LREF PROP
return false;
needsGetElem = false;
}
} else {
if (!emitComputedPropertyName(key)) // ... RHS RHS KEY
if (!emitComputedPropertyName(key)) // ... RHS *LREF RHS KEY
return false;
}
subpattern = member->pn_right;
}
// Get the property value if not done already.
if (needsGetElem && !emitElemOpBase(JSOP_GETELEM)) // ... RHS PROP
if (needsGetElem && !emitElemOpBase(JSOP_GETELEM)) // ... RHS *LREF PROP
return false;
if (subpattern->isKind(PNK_ASSIGN)) {
if (!emitDefault(subpattern->pn_right, subpattern->pn_left))
if (!emitDefault(subpattern->pn_right, lhs)) // ... RHS *LREF VALUE
return false;
subpattern = subpattern->pn_left;
}
// Destructure PROP per this member's subpattern.
if (!emitDestructuringLHS(subpattern, flav))
// Destructure PROP per this member's lhs.
if (!emitSetOrInitializeDestructuring(subpattern, flav)) // ... RHS
return false;
}