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authorjanekptacijarabaci <janekptacijarabaci@seznam.cz>2018-03-24 12:23:14 +0100
committerjanekptacijarabaci <janekptacijarabaci@seznam.cz>2018-03-24 12:23:14 +0100
commit2bb0252ab48a97a72c33cef9cbe54e86563f15c9 (patch)
tree1b792a95a2ddaed8f3a16e7367b72fff73a51a51 /js/src
parent4b487efb58bfba4c3f67d898e86b9f6daaab59b2 (diff)
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Bug 1147371: Implement IteratorClose for array destructuring
Issue #74
Diffstat (limited to 'js/src')
-rw-r--r--js/src/frontend/BytecodeEmitter.cpp218
-rw-r--r--js/src/frontend/BytecodeEmitter.h3
-rw-r--r--js/src/jit/JitFrames.cpp82
-rw-r--r--js/src/jsscript.h3
-rw-r--r--js/src/shell/js.cpp35
-rw-r--r--js/src/tests/ecma_6/Destructuring/array-iterator-close.js77
-rw-r--r--js/src/vm/Interpreter.cpp39
7 files changed, 322 insertions, 135 deletions
diff --git a/js/src/frontend/BytecodeEmitter.cpp b/js/src/frontend/BytecodeEmitter.cpp
index 2934f63a5..e2c906850 100644
--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -4947,7 +4947,7 @@ 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);
@@ -4956,7 +4956,7 @@ 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;
}
@@ -5057,6 +5057,9 @@ 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
@@ -5064,7 +5067,7 @@ 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;
@@ -5074,10 +5077,10 @@ 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;
@@ -5090,7 +5093,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// value = result.value;
// }
//
- // SetOrInitialize(lref, value);
+ // SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for elision ====
// if (done) {
@@ -5105,7 +5108,7 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
// }
//
// // ==== emitted by loop for c ====
- // lref = GetReference(c);
+ // lref = GetReference(c); // covered by trynote
//
// if (done) {
// value = undefined;
@@ -5119,19 +5122,23 @@ 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.
@@ -5140,25 +5147,61 @@ 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;
- if (member->isKind(PNK_SPREAD)) {
- size_t emitted = 0;
- if (!emitDestructuringLHSRef(member, &emitted)) // ... OBJ ITER ?DONE *LREF
+ 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)) {
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;
@@ -5181,13 +5224,22 @@ 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);
@@ -5195,63 +5247,30 @@ BytecodeEmitter::emitDestructuringOpsArray(ParseNode* pattern, DestructuringFlav
}
ParseNode* pndefault = nullptr;
- ParseNode* subpattern = member;
- if (subpattern->isKind(PNK_ASSIGN)) {
- pndefault = subpattern->pn_right;
- subpattern = subpattern->pn_left;
- }
-
- bool isElision = subpattern->isKind(PNK_ELISION);
-
- MOZ_ASSERT(!subpattern->isKind(PNK_SPREAD));
+ if (member->isKind(PNK_ASSIGN))
+ pndefault = member->pn_right;
- 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) {
@@ -5268,59 +5287,74 @@ 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;
}
diff --git a/js/src/frontend/BytecodeEmitter.h b/js/src/frontend/BytecodeEmitter.h
index 156abedbe..78eb3510c 100644
--- a/js/src/frontend/BytecodeEmitter.h
+++ b/js/src/frontend/BytecodeEmitter.h
@@ -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|.
diff --git a/js/src/jit/JitFrames.cpp b/js/src/jit/JitFrames.cpp
index d6c6fc4c9..30bbd0b9b 100644
--- a/js/src/jit/JitFrames.cpp
+++ b/js/src/jit/JitFrames.cpp
@@ -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);
}
}
@@ -426,14 +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:
@@ -607,28 +621,52 @@ ProcessTryNotesBaseline(JSContext* cx, const JitFrameIterator& frame, Environmen
return true;
}
- case JSTRY_FOR_IN:
- case JSTRY_ITERCLOSE: {
+ case JSTRY_FOR_IN: {
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) {
+ 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_IF(tn->kind == JSTRY_FOR_IN, **pc == JSOP_ENDITER);
+ 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));
+ RootedObject iterObject(cx, &iterValue.toObject());
+ if (!IteratorCloseForException(cx, iterObject)) {
+ SettleOnTryNote(cx, tn, frame, ei, rfe, pc);
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;
diff --git a/js/src/jsscript.h b/js/src/jsscript.h
index b48d48686..8bba3ec39 100644
--- a/js/src/jsscript.h
+++ b/js/src/jsscript.h
@@ -85,7 +85,8 @@ enum JSTryNoteKind {
JSTRY_FOR_IN,
JSTRY_FOR_OF,
JSTRY_LOOP,
- JSTRY_ITERCLOSE
+ JSTRY_ITERCLOSE,
+ JSTRY_DESTRUCTURING_ITERCLOSE
};
/*
diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
index 294dd935d..6fe01de22 100644
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -2585,12 +2585,28 @@ 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)
@@ -2598,17 +2614,16 @@ 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;
}
diff --git a/js/src/tests/ecma_6/Destructuring/array-iterator-close.js b/js/src/tests/ecma_6/Destructuring/array-iterator-close.js
new file mode 100644
index 000000000..f7805540d
--- /dev/null
+++ b/js/src/tests/ecma_6/Destructuring/array-iterator-close.js
@@ -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);
diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index 489d0a155..923c824ce 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -1171,19 +1171,13 @@ 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
@@ -1195,6 +1189,33 @@ 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;