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[vm/compiler] Fix truncation of class id when it is stored in FieldGuardState

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Class id can occupy more than 16 bits, so bit field
FieldGuardState::GuardedCidBits is extended. Also added assertion that
it has at least target::UntaggedObject::kClassIdTagSize bits.

TEST=ci, manually tested repro from b/322790241.
Fixes b/322790241

Change-Id: I39d0592a5a1c8e0c83b7af7d30de6f966b358fda
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/349082
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
This commit is contained in:
Alexander Markov 2024-01-29 23:44:59 +00:00 committed by Commit Queue
parent 72fdb26e04
commit 8c5407b3dd
2 changed files with 5 additions and 2 deletions
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5
runtime/vm/compiler/backend/slot.cc
View file

@ -331,7 +331,10 @@ const Slot& Slot::GetCanonicalSlot(Thread* thread,
FieldGuardState::FieldGuardState(const Field& field)
: state_(GuardedCidBits::encode(field.guarded_cid()) |
IsNullableBit::encode(field.is_nullable())) {}
IsNullableBit::encode(field.is_nullable())) {
ASSERT(compiler::target::UntaggedObject::kClassIdTagSize <=
GuardedCidBits::bitsize());
}
const Slot& Slot::Get(const Field& field,
const ParsedFunction* parsed_function) {

2
runtime/vm/compiler/backend/slot.h
View file

@ -241,7 +241,7 @@ class FieldGuardState {
bool is_nullable() const { return IsNullableBit::decode(state_); }
private:
using GuardedCidBits = BitField<int32_t, ClassIdTagType, 0, 16>;
using GuardedCidBits = BitField<int32_t, ClassIdTagType, 0, 20>;
using IsNullableBit = BitField<int32_t, bool, GuardedCidBits::kNextBit, 1>;
const int32_t state_;