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Bug 1147371 - Implement IteratorClose for array destructuring. (r=arai) 

Since result.done is always needed now, always emit the code that pushes
it on the stack.

For throwing, like for-of, IteratorClose is only called when non-iterator
code throws. Unlike for-of, both the iterator object and the done
boolean value are on the stack for the trynote. IteratorClose is only
called when !done.
This commit is contained in:
Shu-yu Guo 2017-01-14 14:51:38 -08:00
Родитель a40ddf408f
Коммит 9c2567d79e
7 изменённых файлов: 324 добавлений и 136 удалений
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220
js/src/frontend/BytecodeEmitter.cpp
Просмотреть файл

@ -4955,7 +4955,7 @@ BytecodeEmitter::emitIteratorClose(Maybe<JumpTarget> yieldStarTryStart, bool all
template <typename InnerEmitter>
bool
BytecodeEmitter::wrapWithIteratorCloseTryNote(int32_t iterDepth, InnerEmitter emitter)
BytecodeEmitter::wrapWithDestructuringIteratorCloseTryNote(int32_t iterDepth, InnerEmitter emitter)
{
MOZ_ASSERT(this->stackDepth >= iterDepth);
@ -4964,7 +4964,7 @@ BytecodeEmitter::wrapWithIteratorCloseTryNote(int32_t iterDepth, InnerEmitter em
return false;
ptrdiff_t end = offset();
if (start != end)
return tryNoteList.append(JSTRY_ITERCLOSE, iterDepth, start, end);
return tryNoteList.append(JSTRY_DESTRUCTURING_ITERCLOSE, iterDepth, start, end);
return true;
}
@ -5065,6 +5065,9 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// Here's pseudo code for |let [a, b, , c=y, ...d] = x;|
//
// Lines that are annotated "covered by trynote" mean that upon throwing
// an exception, IteratorClose is called on iter only if done is false.
//
// let x, y;
// let a, b, c, d;
// let iter, lref, result, done, value; // stack values
@ -5072,7 +5075,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// iter = x[Symbol.iterator]();
//
// // ==== emitted by loop for a ====
// lref = GetReference(a);
// lref = GetReference(a); // covered by trynote
//
// result = iter.next();
// done = result.done;
@ -5082,10 +5085,10 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// else
// value = result.value;
//
// SetOrInitialize(lref, value);
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for b ====
// lref = GetReference(b);
// lref = GetReference(b); // covered by trynote
//
// if (done) {
// value = undefined;
@ -5098,7 +5101,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// value = result.value;
// }
//
// SetOrInitialize(lref, value);
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for elision ====
// if (done) {
@ -5113,7 +5116,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// }
//
// // ==== emitted by loop for c ====
// lref = GetReference(c);
// lref = GetReference(c); // covered by trynote
//
// if (done) {
// value = undefined;
@ -5127,19 +5130,23 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// }
//
// if (value === undefined)
// value = y;
// value = y; // covered by trynote
//
// SetOrInitialize(lref, value);
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for d ====
// lref = GetReference(d);
// lref = GetReference(d); // covered by trynote
//
// if (done)
// value = [];
// else
// value = [...iter];
//
// SetOrInitialize(lref, value);
// SetOrInitialize(lref, value); // covered by trynote
//
// // === emitted after loop ===
// if (!done)
// IteratorClose(iter);
// Use an iterator to destructure the RHS, instead of index lookup. We
// must leave the *original* value on the stack.
@ -5148,25 +5155,61 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
if (!emitIterator()) // ... OBJ ITER
return false;
// For an empty pattern [], call IteratorClose unconditionally. Nothing
// else needs to be done.
if (!pattern->pn_head)
return emitIteratorClose(); // ... OBJ
// Push an initial FALSE value for DONE.
if (!emit1(JSOP_FALSE)) // ... OBJ ITER FALSE
return false;
// JSTRY_DESTRUCTURING_ITERCLOSE expects the iterator and the done value
// to be the second to top and the top of the stack, respectively.
// IteratorClose is called upon exception only if done is false.
int32_t tryNoteDepth = stackDepth;
for (ParseNode* member = pattern->pn_head; member; member = member->pn_next) {
bool isHead = member == pattern->pn_head;
bool hasNext = !!member->pn_next;
bool isFirst = member == pattern->pn_head;
DebugOnly<bool> hasNext = !!member->pn_next;
size_t emitted = 0;
// Spec requires LHS reference to be evaluated first.
ParseNode* lhsPattern = member;
if (lhsPattern->isKind(PNK_ASSIGN))
lhsPattern = lhsPattern->pn_left;
bool isElision = lhsPattern->isKind(PNK_ELISION);
if (!isElision) {
auto emitLHSRef = [lhsPattern, &emitted](BytecodeEmitter* bce) {
return bce->emitDestructuringLHSRef(lhsPattern, &emitted); // ... OBJ ITER DONE *LREF
};
if (!wrapWithDestructuringIteratorCloseTryNote(tryNoteDepth, emitLHSRef))
return false;
}
// Pick the DONE value to the top of the stack.
if (emitted) {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
if (isFirst) {
// If this element is the first, DONE is always FALSE, so pop it.
//
// Non-first elements should emit if-else depending on the
// member pattern, below.
if (!emit1(JSOP_POP)) // ... OBJ ITER *LREF
return false;
}
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 (!isFirst) {
// If spread is not the first element of the pattern,
// iterator can already be completed.
// ... OBJ ITER DONE *LREF
if (emitted) {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
// ... OBJ ITER *LREF DONE
if (!ifThenElse.emitIfElse()) // ... OBJ ITER *LREF
return false;
@ -5189,13 +5232,22 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
if (!emit1(JSOP_POP)) // ... OBJ ITER *LREF ARRAY
return false;
if (!isHead) {
if (!isFirst) {
if (!ifThenElse.emitEnd())
return false;
MOZ_ASSERT(ifThenElse.pushed() == 1);
}
if (!emitSetOrInitializeDestructuring(member, flav)) // ... OBJ ITER
// At this point the iterator is done. Unpick a TRUE value for DONE above ITER.
if (!emit1(JSOP_TRUE)) // ... OBJ ITER *LREF ARRAY TRUE
return false;
if (!emit2(JSOP_UNPICK, emitted + 1)) // ... OBJ ITER TRUE *LREF ARRAY
return false;
auto emitAssignment = [member, flav](BytecodeEmitter* bce) {
return bce->emitSetOrInitializeDestructuring(member, flav); // ... OBJ ITER TRUE
};
if (!wrapWithDestructuringIteratorCloseTryNote(tryNoteDepth, emitAssignment))
return false;
MOZ_ASSERT(!hasNext);
@ -5203,63 +5255,30 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
}
ParseNode* pndefault = nullptr;
ParseNode* subpattern = member;
if (subpattern->isKind(PNK_ASSIGN)) {
pndefault = subpattern->pn_right;
subpattern = subpattern->pn_left;
}
if (member->isKind(PNK_ASSIGN))
pndefault = member->pn_right;
bool isElision = subpattern->isKind(PNK_ELISION);
MOZ_ASSERT(!subpattern->isKind(PNK_SPREAD));
size_t emitted = 0;
if (!isElision) {
if (!emitDestructuringLHSRef(subpattern, &emitted)) // ... OBJ ITER ?DONE *LREF
return false;
}
MOZ_ASSERT(!member->isKind(PNK_SPREAD));
IfThenElseEmitter ifAlreadyDone(this);
if (!isHead) {
// If this element is not the first element of the pattern,
// iterator can already be completed.
// ... 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 *LREF
if (!isFirst) {
// ... OBJ ITER *LREF DONE
if (!ifAlreadyDone.emitIfElse()) // ... OBJ ITER *LREF
return false;
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE *LREF UNDEF
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER *LREF UNDEF
return false;
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE *LREF UNDEF
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER *LREF UNDEF
return false;
if (!ifAlreadyDone.emitElse()) // ... OBJ ITER ?DONE *LREF
// The iterator is done. Unpick a TRUE value for DONE above ITER.
if (!emit1(JSOP_TRUE)) // ... OBJ ITER *LREF UNDEF TRUE
return false;
if (!emit2(JSOP_UNPICK, emitted + 1)) // ... OBJ ITER TRUE *LREF UNDEF
return false;
if (hasNext) {
if (emitted) {
if (!emit2(JSOP_PICK, emitted)) // ... OBJ ITER *LREF DONE
return false;
}
if (!emit1(JSOP_POP)) // ... OBJ ITER *LREF
return false;
}
if (!ifAlreadyDone.emitElse()) // ... OBJ ITER *LREF
return false;
}
if (emitted) {
@ -5276,59 +5295,74 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
if (!emitAtomOp(cx->names().done, JSOP_GETPROP)) // ... OBJ ITER *LREF RESULT DONE
return false;
if (hasNext) {
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;
}
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 ?DONE *LREF RESULT
if (!ifDone.emitIfElse()) // ... OBJ ITER DONE *LREF RESULT
return false;
if (!emit1(JSOP_POP)) // ... OBJ ITER ?DONE *LREF
if (!emit1(JSOP_POP)) // ... OBJ ITER DONE *LREF
return false;
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER ?DONE *LREF UNDEF
if (!emit1(JSOP_UNDEFINED)) // ... OBJ ITER DONE *LREF UNDEF
return false;
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER ?DONE *LREF UNDEF
if (!emit1(JSOP_NOP_DESTRUCTURING)) // ... OBJ ITER DONE *LREF UNDEF
return false;
if (!ifDone.emitElse()) // ... OBJ ITER ?DONE *LREF RESULT
if (!ifDone.emitElse()) // ... OBJ ITER DONE *LREF RESULT
return false;
if (!emitAtomOp(cx->names().value, JSOP_GETPROP)) // ... OBJ ITER ?DONE *LREF VALUE
if (!emitAtomOp(cx->names().value, JSOP_GETPROP)) // ... OBJ ITER DONE *LREF VALUE
return false;
if (!ifDone.emitEnd())
return false;
MOZ_ASSERT(ifDone.pushed() == 0);
if (!isHead) {
if (!isFirst) {
if (!ifAlreadyDone.emitEnd())
return false;
MOZ_ASSERT(ifAlreadyDone.pushed() == 1);
MOZ_ASSERT(ifAlreadyDone.pushed() == 2);
}
if (pndefault) {
if (!emitDefault(pndefault, subpattern)) // ... OBJ ITER ?DONE *LREF VALUE
auto emitDefault = [pndefault, lhsPattern](BytecodeEmitter* bce) {
return bce->emitDefault(pndefault, lhsPattern); // ... OBJ ITER DONE *LREF VALUE
};
if (!wrapWithDestructuringIteratorCloseTryNote(tryNoteDepth, emitDefault))
return false;
}
if (!isElision) {
if (!emitSetOrInitializeDestructuring(subpattern,
flav)) // ... OBJ ITER ?DONE
{
auto emitAssignment = [lhsPattern, flav](BytecodeEmitter* bce) {
return bce->emitSetOrInitializeDestructuring(lhsPattern, flav); // ... OBJ ITER DONE
};
if (!wrapWithDestructuringIteratorCloseTryNote(tryNoteDepth, emitAssignment))
return false;
}
} else {
if (!emit1(JSOP_POP)) // ... OBJ ITER ?DONE
if (!emit1(JSOP_POP)) // ... OBJ ITER DONE
return false;
}
}
// The last DONE value is on top of the stack. If not DONE, call
// IteratorClose.
// ... OBJ ITER DONE
IfThenElseEmitter ifDone(this);
if (!ifDone.emitIfElse()) // ... OBJ ITER
return false;
if (!emit1(JSOP_POP)) // ... OBJ
return false;
if (!ifDone.emitElse()) // ... OBJ ITER
return false;
if (!emitIteratorClose()) // ... OBJ
return false;
if (!ifDone.emitEnd())
return false;
return true;
}

3
js/src/frontend/BytecodeEmitter.h
Просмотреть файл

@ -684,7 +684,8 @@ struct MOZ_STACK_CLASS BytecodeEmitter
bool allowSelfHosted = false);
template <typename InnerEmitter>
MOZ_MUST_USE bool wrapWithIteratorCloseTryNote(int32_t iterDepth, InnerEmitter emitter);
MOZ_MUST_USE bool wrapWithDestructuringIteratorCloseTryNote(int32_t iterDepth,
InnerEmitter emitter);
// Check if the value on top of the stack is "undefined". If so, replace
// that value on the stack with the value defined by |defaultExpr|.

83
js/src/jit/JitFrames.cpp
Просмотреть файл

@ -330,28 +330,44 @@ NumArgAndLocalSlots(const InlineFrameIterator& frame)
static void
CloseLiveIteratorIon(JSContext* cx, const InlineFrameIterator& frame, JSTryNote* tn)
{
MOZ_ASSERT(tn->kind == JSTRY_FOR_IN || tn->kind == JSTRY_ITERCLOSE);
MOZ_ASSERT(tn->stackDepth > 0);
MOZ_ASSERT(tn->kind == JSTRY_FOR_IN ||
tn->kind == JSTRY_ITERCLOSE ||
tn->kind == JSTRY_DESTRUCTURING_ITERCLOSE);
bool isDestructuring = tn->kind == JSTRY_DESTRUCTURING_ITERCLOSE;
MOZ_ASSERT_IF(!isDestructuring, tn->stackDepth > 0);
MOZ_ASSERT_IF(isDestructuring, tn->stackDepth > 1);
SnapshotIterator si = frame.snapshotIterator();
// Skip stack slots until we reach the iterator object.
// Skip stack slots until we reach the iterator object on the stack. For
// the destructuring case, we also need to get the "done" value.
uint32_t stackSlot = tn->stackDepth;
uint32_t skipSlots = NumArgAndLocalSlots(frame) + stackSlot - 1;
uint32_t adjust = isDestructuring ? 2 : 1;
uint32_t skipSlots = NumArgAndLocalSlots(frame) + stackSlot - adjust;
for (unsigned i = 0; i < skipSlots; i++)
si.skip();
Value v = si.read();
RootedObject obj(cx, &v.toObject());
RootedObject iterObject(cx, &v.toObject());
if (isDestructuring) {
Value v = si.read();
MOZ_ASSERT(v.isBoolean());
// Do not call IteratorClose if the destructuring iterator is already
// done.
if (v.isTrue())
return;
}
if (cx->isExceptionPending()) {
if (tn->kind == JSTRY_FOR_IN)
UnwindIteratorForException(cx, obj);
UnwindIteratorForException(cx, iterObject);
else
IteratorCloseForException(cx, obj);
IteratorCloseForException(cx, iterObject);
} else {
UnwindIteratorForUncatchableException(cx, obj);
UnwindIteratorForUncatchableException(cx, iterObject);
}
}
@ -426,13 +442,12 @@ HandleExceptionIon(JSContext* cx, const InlineFrameIterator& frame, ResumeFromEx
switch (tn->kind) {
case JSTRY_FOR_IN:
case JSTRY_ITERCLOSE: {
case JSTRY_ITERCLOSE:
case JSTRY_DESTRUCTURING_ITERCLOSE:
MOZ_ASSERT_IF(tn->kind == JSTRY_FOR_IN,
JSOp(*(script->main() + tn->start + tn->length)) == JSOP_ENDITER);
MOZ_ASSERT(tn->stackDepth > 0);
CloseLiveIteratorIon(cx, frame, tn);
break;
}
case JSTRY_FOR_OF:
case JSTRY_LOOP:
@ -606,28 +621,52 @@ ProcessTryNotesBaseline(JSContext* cx, const JitFrameIterator& frame, Environmen
return true;
}
case JSTRY_FOR_IN:
case JSTRY_FOR_IN: {
uint8_t* framePointer;
uint8_t* stackPointer;
BaselineFrameAndStackPointersFromTryNote(tn, frame, &framePointer, &stackPointer);
Value iterValue(*reinterpret_cast<Value*>(stackPointer));
RootedObject iterObject(cx, &iterValue.toObject());
if (!UnwindIteratorForException(cx, iterObject)) {
// See comment in the JSTRY_FOR_IN case in Interpreter.cpp's
// ProcessTryNotes.
SettleOnTryNote(cx, tn, frame, ei, rfe, pc);
MOZ_ASSERT(**pc == JSOP_ENDITER);
return false;
}
break;
}
case JSTRY_ITERCLOSE: {
uint8_t* framePointer;
uint8_t* stackPointer;
BaselineFrameAndStackPointersFromTryNote(tn, frame, &framePointer, &stackPointer);
Value iterValue(*(reinterpret_cast<Value*>(stackPointer)));
Value iterValue(*reinterpret_cast<Value*>(stackPointer));
RootedObject iterObject(cx, &iterValue.toObject());
bool ok;
if (tn->kind == JSTRY_FOR_IN)
ok = UnwindIteratorForException(cx, iterObject);
else
ok = IteratorCloseForException(cx, iterObject);
if (!ok) {
// See comment in the JSTRY_FOR_IN case in Interpreter.cpp's
// ProcessTryNotes.
if (!IteratorCloseForException(cx, iterObject)) {
SettleOnTryNote(cx, tn, frame, ei, rfe, pc);
MOZ_ASSERT_IF(tn->kind == JSTRY_FOR_IN, **pc == JSOP_ENDITER);
return false;
}
break;
}
case JSTRY_DESTRUCTURING_ITERCLOSE: {
uint8_t* framePointer;
uint8_t* stackPointer;
BaselineFrameAndStackPointersFromTryNote(tn, frame, &framePointer, &stackPointer);
Value doneValue(*(reinterpret_cast<Value*>(stackPointer)));
MOZ_ASSERT(doneValue.isBoolean());
if (doneValue.isFalse()) {
Value iterValue(*(reinterpret_cast<Value*>(stackPointer) + 1));
RootedObject iterObject(cx, &iterValue.toObject());
if (!IteratorCloseForException(cx, iterObject)) {
SettleOnTryNote(cx, tn, frame, ei, rfe, pc);
return false;
}
}
break;
}
case JSTRY_FOR_OF:
case JSTRY_LOOP:
break;

3
js/src/jsscript.h
Просмотреть файл

@ -85,7 +85,8 @@ enum JSTryNoteKind {
JSTRY_FOR_IN,
JSTRY_FOR_OF,
JSTRY_LOOP,
JSTRY_ITERCLOSE
JSTRY_ITERCLOSE,
JSTRY_DESTRUCTURING_ITERCLOSE
};
/*

35
js/src/shell/js.cpp
Просмотреть файл

@ -2589,12 +2589,28 @@ Notes(JSContext* cx, unsigned argc, Value* vp)
return true;
}
JS_STATIC_ASSERT(JSTRY_CATCH == 0);
JS_STATIC_ASSERT(JSTRY_FINALLY == 1);
JS_STATIC_ASSERT(JSTRY_FOR_IN == 2);
static const char*
TryNoteName(JSTryNoteKind kind)
{
switch (kind) {
case JSTRY_CATCH:
return "catch";
case JSTRY_FINALLY:
return "finally";
case JSTRY_FOR_IN:
return "for-in";
case JSTRY_FOR_OF:
return "for-of";
case JSTRY_LOOP:
return "loop";
case JSTRY_ITERCLOSE:
return "iterclose";
case JSTRY_DESTRUCTURING_ITERCLOSE:
return "dstr-iterclose";
}
static const char* const TryNoteNames[] = { "catch", "finally", "for-in", "for-of", "loop",
"iterclose" };
MOZ_CRASH("Bad JSTryNoteKind");
}
static MOZ_MUST_USE bool
TryNotes(JSContext* cx, HandleScript script, Sprinter* sp)
@ -2602,17 +2618,16 @@ TryNotes(JSContext* cx, HandleScript script, Sprinter* sp)
if (!script->hasTrynotes())
return true;
if (sp->put("\nException table:\nkind stack start end\n") < 0)
if (sp->put("\nException table:\nkind stack start end\n") < 0)
return false;
JSTryNote* tn = script->trynotes()->vector;
JSTryNote* tnlimit = tn + script->trynotes()->length;
do {
MOZ_ASSERT(tn->kind < ArrayLength(TryNoteNames));
uint32_t startOff = script->pcToOffset(script->main()) + tn->start;
if (!sp->jsprintf(" %-9s %6u %8u %8u\n",
TryNoteNames[tn->kind], tn->stackDepth,
startOff, startOff + tn->length))
if (!sp->jsprintf(" %-14s %6u %8u %8u\n",
TryNoteName(static_cast<JSTryNoteKind>(tn->kind)),
tn->stackDepth, startOff, startOff + tn->length))
{
return false;
}

77
js/src/tests/ecma_6/Destructuring/array-iterator-close.js Normal file
Просмотреть файл

@ -0,0 +1,77 @@
// Tests that IteratorClose is called in array destructuring patterns.
function test() {
var returnCalled = 0;
var returnCalledExpected = 0;
var iterable = {};
// empty [] calls IteratorClose regardless of "done" on the result.
iterable[Symbol.iterator] = makeIterator({
next: function() {
return { done: true };
},
ret: function() {
returnCalled++;
return {};
}
});
var [] = iterable;
assertEq(returnCalled, ++returnCalledExpected);
iterable[Symbol.iterator] = makeIterator({
ret: function() {
returnCalled++;
return {};
}
});
var [] = iterable;
assertEq(returnCalled, ++returnCalledExpected);
// Non-empty destructuring calls IteratorClose if iterator is not done by
// the end of destructuring.
var [a,b] = iterable;
assertEq(returnCalled, ++returnCalledExpected);
var [c,] = iterable;
assertEq(returnCalled, ++returnCalledExpected);
// throw in lhs ref calls IteratorClose
function throwlhs() {
throw "in lhs";
}
assertThrowsValue(function() {
0, [...{}[throwlhs()]] = iterable;
}, "in lhs");
assertEq(returnCalled, ++returnCalledExpected);
// throw in iter.next doesn't call IteratorClose
iterable[Symbol.iterator] = makeIterator({
next: function() {
throw "in next";
},
ret: function() {
returnCalled++;
return {};
}
});
assertThrowsValue(function() {
var [d] = iterable;
}, "in next");
assertEq(returnCalled, returnCalledExpected);
// "return" must return an Object.
iterable[Symbol.iterator] = makeIterator({
ret: function() {
returnCalled++;
return 42;
}
});
assertThrowsInstanceOf(function() {
var [] = iterable;
}, TypeError);
assertEq(returnCalled, ++returnCalledExpected);
}
test();
if (typeof reportCompare === "function")
reportCompare(0, 0);

39
js/src/vm/Interpreter.cpp
Просмотреть файл

@ -1174,19 +1174,13 @@ ProcessTryNotes(JSContext* cx, EnvironmentIter& ei, InterpreterRegs& regs)
SettleOnTryNote(cx, tn, ei, regs);
return FinallyContinuation;
case JSTRY_FOR_IN:
case JSTRY_ITERCLOSE: {
case JSTRY_FOR_IN: {
/* This is similar to JSOP_ENDITER in the interpreter loop. */
DebugOnly<jsbytecode*> pc = regs.fp()->script()->main() + tn->start + tn->length;
MOZ_ASSERT_IF(tn->kind == JSTRY_FOR_IN, JSOp(*pc) == JSOP_ENDITER);
MOZ_ASSERT(JSOp(*pc) == JSOP_ENDITER);
Value* sp = regs.spForStackDepth(tn->stackDepth);
RootedObject obj(cx, &sp[-1].toObject());
bool ok;
if (tn->kind == JSTRY_FOR_IN)
ok = UnwindIteratorForException(cx, obj);
else
ok = IteratorCloseForException(cx, obj);
if (!ok) {
if (!UnwindIteratorForException(cx, obj)) {
// We should only settle on the note only if
// UnwindIteratorForException itself threw, as
// onExceptionUnwind should be called anew with the new
@ -1198,6 +1192,33 @@ ProcessTryNotes(JSContext* cx, EnvironmentIter& ei, InterpreterRegs& regs)
break;
}
case JSTRY_ITERCLOSE: {
// The iterator object is at the top of the stack.
Value* sp = regs.spForStackDepth(tn->stackDepth);
RootedObject iterObject(cx, &sp[-1].toObject());
if (!IteratorCloseForException(cx, iterObject)) {
SettleOnTryNote(cx, tn, ei, regs);
return ErrorReturnContinuation;
}
break;
}
case JSTRY_DESTRUCTURING_ITERCLOSE: {
// Whether the destructuring iterator is done is at the top of the
// stack. The iterator object is second from the top.
MOZ_ASSERT(tn->stackDepth > 1);
Value* sp = regs.spForStackDepth(tn->stackDepth);
MOZ_ASSERT(sp[-1].isBoolean());
if (sp[-1].isFalse()) {
RootedObject iterObject(cx, &sp[-2].toObject());
if (!IteratorCloseForException(cx, iterObject)) {
SettleOnTryNote(cx, tn, ei, regs);
return ErrorReturnContinuation;
}
}
break;
}
case JSTRY_FOR_OF:
case JSTRY_LOOP:
break;