Files
carbon-lang/explorer/interpreter/heap.cpp
T
Adrien Leravat df289efac4 Explorer: Add virtual destructor support (#2695)
### Features

* Add virtual `destructor`s support (Closes #2521)
* Check virtual override for virtual destructors
* Error if attempting to `Delete` a class that does not have virtual destructors from a base class pointer 

### Implementation

* Update parser to support virtual override introducers for destructors
* Check virtual override for class destructor and add to class vtable if necessary
* Add corresponding tests

### Notes

Contrary to initial implementation, this implementation leverages the `Address` structure and implements a new `Address::DowncastedAddress()` method to get address from child most class from a base class address. This avoids the need to use `GetAllocationId` and its issues when it comes to having multiple values for an `AllocationId`.

### Next work

Following this PR, we need to:

* Check when using `Delete` that the class was allocated with `New` (WIP)
* Drop the old `GetAllocationId(Value*)` in favor of a better system (WIP)
2023-03-22 09:58:30 -07:00

107 lines
3.5 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "explorer/interpreter/heap.h"
#include "explorer/ast/value.h"
#include "explorer/common/error_builders.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Error.h"
namespace Carbon {
auto Heap::AllocateValue(Nonnull<const Value*> v) -> AllocationId {
// Putting the following two side effects together in this function
// ensures that we don't do anything else in between, which would be really
// bad! Consider whether to include a copy of the input v in this function or
// to leave it up to the caller.
AllocationId a(values_.size());
values_.push_back(v);
if (v->kind() == Carbon::Value::Kind::UninitializedValue) {
states_.push_back(ValueState::Uninitialized);
} else {
states_.push_back(ValueState::Alive);
}
return a;
}
auto Heap::Read(const Address& a, SourceLocation source_loc) const
-> ErrorOr<Nonnull<const Value*>> {
CARBON_RETURN_IF_ERROR(this->CheckInit(a.allocation_, source_loc));
CARBON_RETURN_IF_ERROR(this->CheckAlive(a.allocation_, source_loc));
Nonnull<const Value*> value = values_[a.allocation_.index_];
return value->GetElement(arena_, a.element_path_, source_loc, value);
}
auto Heap::Write(const Address& a, Nonnull<const Value*> v,
SourceLocation source_loc) -> ErrorOr<Success> {
CARBON_RETURN_IF_ERROR(this->CheckAlive(a.allocation_, source_loc));
if (states_[a.allocation_.index_] == ValueState::Uninitialized) {
states_[a.allocation_.index_] = ValueState::Alive;
}
CARBON_ASSIGN_OR_RETURN(values_[a.allocation_.index_],
values_[a.allocation_.index_]->SetField(
arena_, a.element_path_, v, source_loc));
return Success();
}
auto Heap::GetAllocationId(Nonnull<const Value*> v) const
-> std::optional<AllocationId> {
auto iter = std::find(values_.begin(), values_.end(), v);
if (iter != values_.end()) {
auto index = iter - values_.begin();
if (states_[index] == ValueState::Alive) {
return AllocationId(index);
}
}
return std::nullopt;
}
auto Heap::CheckAlive(AllocationId allocation, SourceLocation source_loc) const
-> ErrorOr<Success> {
if (states_[allocation.index_] == ValueState::Dead) {
return ProgramError(source_loc)
<< "undefined behavior: access to dead value "
<< *values_[allocation.index_];
}
return Success();
}
auto Heap::CheckInit(AllocationId allocation, SourceLocation source_loc) const
-> ErrorOr<Success> {
if (states_[allocation.index_] == ValueState::Uninitialized) {
return ProgramError(source_loc)
<< "undefined behavior: access to uninitialized value "
<< *values_[allocation.index_];
}
return Success();
}
void Heap::Deallocate(AllocationId allocation) {
if (states_[allocation.index_] != ValueState::Dead) {
states_[allocation.index_] = ValueState::Dead;
} else {
CARBON_FATAL() << "deallocating an already dead value: "
<< *values_[allocation.index_];
}
}
void Heap::Deallocate(const Address& a) { Deallocate(a.allocation_); }
void Heap::Print(llvm::raw_ostream& out) const {
llvm::ListSeparator sep;
for (size_t i = 0; i < values_.size(); ++i) {
out << sep;
out << i << ": ";
if (states_[i] == ValueState::Uninitialized) {
out << "!";
} else if (states_[i] == ValueState::Dead) {
out << "!!";
}
out << *values_[i];
}
}
} // namespace Carbon