This is an extension of cc0b970d but for the reference-handling
specialization of Optional.
This basically allow us to write code like:
```cpp
Optional<u8&> opt;
opt = OptionalNone{};
```
This allows the user to transform the contents of the optional (if any
exists), without manually unwrapping and then rewrapping it.
This is needed by the Jakt runtime.
This patch adds the `USING_AK_GLOBALLY` macro which is enabled by
default, but can be overridden by build flags.
This is a step towards integrating Jakt and AK types.
This implements Optional<T&> as a T*, whose presence has been missing
since the early days of Optional.
As a lot of find_foo() APIs return an Optional<T> which imposes a
pointless copy on the underlying value, and can sometimes be very
misleading, with this change, those APIs can return Optional<T&>.
This bit me because I accidentally made the destructor for a class which
was wrapped in an Optional private. This causes none of the Optional
destructors to be able to be deduced, which when combined with concepts
causes an internal compile error in GCC 10.3.0+. This commit adds a note
here to make sure that future encounters of this bug does not surprise
people.
This avoids a value copy when calling value() or value_or() on a
temporary Optional. This is very common when using the HashMap::get()
API like this:
auto value = hash_map.get(key).value_or(fallback_value);
This commit makes use of the conditionally trivial special member
functions introduced in C++20. Basically, `Optional` and `Variant`
inherits whether its wrapped type is trivially copy constructible,
trivially copy assignable or trivially destructible. This lets the
compiler optimize optimize a large number of their use cases.
The constraints have been applied to `Optional`'s converting
constructors too in order to make the API more explicit.
This feature is not supported by Clang yet, so we use conditional
compilation so that Lagom can be built on macOS. Once Clang has P0848R3
support, these can be removed.
When creating uninitialized storage for variables, we need to make sure
that the alignment is correct. Fixes a KUBSAN failure when running
kernels compiled with Clang.
In `Syscalls/socket.cpp`, we can simply use local variables, as
`sockaddr_un` is a POD type.
Along with moving the `alignas` specifier to the correct member,
`AK::Optional`'s internal buffer has been made non-zeroed by default.
GCC emitted bogus uninitialized memory access warnings, so we now use
`__builtin_launder` to tell the compiler that we know what we are doing.
This might disable some optimizations, but judging by how GCC failed to
notice that the memory's initialization is dependent on `m_has_value`,
I'm not sure that's a bad thing.
This patch introduces a new operator== to compare an Optional to its
contained type directly. If the Optional does not contain a value, the
comparison will always return false.
This also adds a test case for the new behavior as well as comparison
between Optional objects themselves.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
There is no reason to call a getter without observing the result, doing
so indicates an error in the code. Mark these methods as [[nodiscard]]
to find these cases.
Arbitrarily split up to make git bisect easier.
These unnecessary #include's were found by combining an automated tool (which
determined likely candidates) and some brain power (which decided whether
the #include is also semantically superfluous).
Problem:
- Many constructors are defined as `{}` rather than using the ` =
default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
instead of requiring the caller to default construct. This violates
the C++ Core Guidelines suggestion to declare single-argument
constructors explicit
(https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).
Solution:
- Change default constructors to use the compiler-provided default
constructor.
- Remove implicit conversion operators from `nullptr_t` and change
usage to enforce type consistency without conversion.
Compared to version 10 this fixes a bunch of formatting issues, mostly
around structs/classes with attributes like [[gnu::packed]], and
incorrect insertion of spaces in parameter types ("T &"/"T &&").
I also removed a bunch of // clang-format off/on and FIXME comments that
are no longer relevant - on the other hand it tried to destroy a couple of
neatly formatted comments, so I had to add some as well.
Problem:
- Several files have missing includes. This results in complaints from
`clang-tidy`.
- `#ifdef` is followed by `#elif <value>` which evaluates to `0`.
Solution:
- Add missing includes.
- Change to `#elif defined(<value>)`.
This stopped working quite some time ago due to Clang losing track of
typestates for some reason and everything becoming "unknown".
Since we're primarily using GCC anyway, it doesn't seem worth it to try
and maintain this non-working experiment for a secondary compiler.
Also it doesn't look like the Clang team is actively maintaining this
flag anyway. So good-bye, -Wconsumed. :/
This turns into much less code in the most common cases, here's why:
The normal Optional usage pattern is something like:
auto foo = get_me_an_optional();
if (foo.has_value())
do_stuff_with(foo.value());
In this typical scenario, we check has_value() before calling value().
Without inlining, value() will double-check has_value() itself and
assert if it fails. Inlining allows the compiler to optimize all of
this away.
Move the "fast memcpy" stuff out of StdLibExtras.h and into Memory.h.
This will break a ton of things that were relying on StdLibExtras.h
to include a bunch of other headers. Fix will follow immediately after.
This makes it possible to include StdLibExtras.h from Types.h, which is
the main point of this exercise.
We can use __builtin_memset() without including <string.h>.
This is pretty neat, as it will allow us to reduce the header deps
of AK templates a bit, if applied consistently.
Note that this is an enabling change for an upcoming #include removal.
This was causing some obvious-in-hindsight but hard to spot bugs where
we'd implicitly convert the bool to an integer type and carry on with
the number 1 instead of the actual value().
As suggested by Joshua, this commit adds the 2-clause BSD license as a
comment block to the top of every source file.
For the first pass, I've just added myself for simplicity. I encourage
everyone to add themselves as copyright holders of any file they've
added or modified in some significant way. If I've added myself in
error somewhere, feel free to replace it with the appropriate copyright
holder instead.
Going forward, all new source files should include a license header.
We use consumable annotations to catch bugs where you get the .value()
of an Optional before verifying that it's okay.
The bug here was that only has_value() would set the consumed state,
even though operator bool() does the same job.
This replaces Optional<T>(U&&) which clang-tidy complained may hide the
regular copy and move constructors. That's a good point, clang-tidy,
and I appreciate you pointing that out!
