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[serializer] DCHECK deserializer allocations are initialized

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Add a DCHECK during deserializer allocation that the previous allocation
is sufficiently initialized to be iterable. This is an step towards
allowing GC during deserializer execution.

Bug: v8:10815
Change-Id: I29da21b93e6b826bdb7b5f9f5a9723da1698a225
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2396079
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69802}
This commit is contained in:
Leszek Swirski 2020-09-10 12:54:49 +02:00 committed by Commit Bot
parent 6798619a69
commit fbc1f32d8e
2 changed files with 33 additions and 5 deletions
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32
src/snapshot/deserializer-allocator.cc
View File

@ -64,6 +64,22 @@ Address DeserializerAllocator::AllocateRaw(SnapshotSpace space, int size) {
}
Address DeserializerAllocator::Allocate(SnapshotSpace space, int size) {
#ifdef DEBUG
if (previous_allocation_start_ != kNullAddress) {
// Make sure that the previous allocation is initialized sufficiently to
// be iterated over by the GC.
Address object_address = previous_allocation_start_;
Address previous_allocation_end =
previous_allocation_start_ + previous_allocation_size_;
while (object_address != previous_allocation_end) {
int object_size = HeapObject::FromAddress(object_address).Size();
DCHECK_GT(object_size, 0);
DCHECK_LE(object_address + object_size, previous_allocation_end);
object_address += object_size;
}
}
#endif
Address address;
HeapObject obj;
// TODO(steveblackburn) Note that the third party heap allocates objects
@ -80,9 +96,9 @@ Address DeserializerAllocator::Allocate(SnapshotSpace space, int size) {
// abstracting away the details of the memory allocator from this code.
// At each allocation, the regular allocator performs allocation,
// and a fixed-sized table is used to track and fix all back references.
if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return AllocateRaw(space, size);
if (next_alignment_ != kWordAligned) {
if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) {
address = AllocateRaw(space, size);
} else if (next_alignment_ != kWordAligned) {
const int reserved = size + Heap::GetMaximumFillToAlign(next_alignment_);
address = AllocateRaw(space, reserved);
obj = HeapObject::FromAddress(address);
@ -95,10 +111,16 @@ Address DeserializerAllocator::Allocate(SnapshotSpace space, int size) {
obj = Heap::AlignWithFiller(roots_, obj, size, reserved, next_alignment_);
address = obj.address();
next_alignment_ = kWordAligned;
return address;
} else {
return AllocateRaw(space, size);
address = AllocateRaw(space, size);
}
#ifdef DEBUG
previous_allocation_start_ = address;
previous_allocation_size_ = size;
#endif
return address;
}
void DeserializerAllocator::MoveToNextChunk(SnapshotSpace space) {

6
src/snapshot/deserializer-allocator.h
View File

@ -73,6 +73,12 @@ class DeserializerAllocator final {
uint32_t current_chunk_[kNumberOfPreallocatedSpaces];
Address high_water_[kNumberOfPreallocatedSpaces];
#ifdef DEBUG
// Record the previous object allocated for DCHECKs.
Address previous_allocation_start_ = kNullAddress;
int previous_allocation_size_ = 0;
#endif
// The alignment of the next allocation.
AllocationAlignment next_alignment_ = kWordAligned;