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LibJS/Bytecode: Don't fuse unrelated compare and jump in peephole pass

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Fixes an issue where https://x.com/awesomekling crashed on load. :^)
This commit is contained in:
Andreas Kling 2024-03-05 12:47:48 +01:00
parent 0f8c6dc9ad
commit c1dbde72e9
Notes: sideshowbarker 2024-07-17 08:13:43 +09:00
2 changed files with 28 additions and 21 deletions
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39
Userland/Libraries/LibJS/Bytecode/Pass/Peephole.cpp
View file

@ -40,32 +40,29 @@ void Peephole::perform(PassPipelineExecutable& executable)
if (instruction.type() == Instruction::Type::Not) { if (instruction.type() == Instruction::Type::Not) {
auto const& not_ = static_cast<Op::Not const&>(instruction); auto const& not_ = static_cast<Op::Not const&>(instruction);
VERIFY(jump.condition() == not_.dst()); if (jump.condition() != not_.dst()) {
new_block->append<Op::JumpIfNot>( auto slot_offset = new_block->size();
not_.source_record().source_start_offset, new_block->grow(not_.length());
not_.source_record().source_end_offset, memcpy(new_block->data() + slot_offset, &not_, not_.length());
not_.src(), continue;
*jump.true_target(), }
*jump.false_target());
++it;
VERIFY(it.at_end());
continue;
} }
#define DO_FUSE_JUMP(PreOp, ...) \ #define DO_FUSE_JUMP(PreOp, ...) \
if (instruction.type() == Instruction::Type::PreOp) { \ if (instruction.type() == Instruction::Type::PreOp) { \
auto const& compare = static_cast<Op::PreOp const&>(instruction); \ auto const& compare = static_cast<Op::PreOp const&>(instruction); \
VERIFY(jump.condition() == compare.dst()); \ if (jump.condition() == compare.dst()) { \
new_block->append<Op::Jump##PreOp>( \ new_block->append<Op::Jump##PreOp>( \
compare.source_record().source_start_offset, \ compare.source_record().source_start_offset, \
compare.source_record().source_end_offset, \ compare.source_record().source_end_offset, \
compare.lhs(), \ compare.lhs(), \
compare.rhs(), \ compare.rhs(), \
*jump.true_target(), \ *jump.true_target(), \
*jump.false_target()); \ *jump.false_target()); \
++it; \ ++it; \
VERIFY(it.at_end()); \ VERIFY(it.at_end()); \
continue; \ continue; \
} \
} }
JS_ENUMERATE_FUSABLE_BINARY_OPS(DO_FUSE_JUMP) JS_ENUMERATE_FUSABLE_BINARY_OPS(DO_FUSE_JUMP)
} }

10
Userland/Libraries/LibJS/Tests/optimizer-bugs.js Normal file
View file

@ -0,0 +1,10 @@
test("Don't fuse unrelated jump and compare", () => {
function go(a) {
a < 3;
a &&= 1;
a < 3;
a ||= 1;
}
go();
});