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-rw-r--r--js/src/frontend/BytecodeEmitter.cpp218
-rw-r--r--js/src/frontend/BytecodeEmitter.h3
2 files changed, 128 insertions, 93 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|.
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-04 07:01:58 +0000