diff options
Diffstat (limited to 'js/src/frontend/BytecodeEmitter.cpp')
| -rw-r--r-- | js/src/frontend/BytecodeEmitter.cpp | 218 |
1 files changed, 126 insertions, 92 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; } |