nullptr was being returned in the error case, which, at a glance may
seem perfectly OK... until you realize that std::string has the
invariant that it may not be constructed from a null pointer. This
means that if this error case was ever hit, then the application would
most likely crash from a thrown exception in std::string's constructor.
Instead, we can change the function to return an optional value,
indicating if a failure occurred.
Makes the parameter ordering consistent, and also makes the filename
parameter a std::string. A std::string would be constructed anyways with
the previous code, as IOFile's only constructor with a filepath is one
taking a std::string.
We can also make WriteStringToFile's string parameter utilize a
std::string_view for the string, making use of our previous changes to
IOFile.
We don't need to force the usage of a std::string here, and can instead
use a std::string_view, which allows writing out other forms of strings
(e.g. C-style strings) without any unnecessary heap allocations.
Uses arithmetic that can be identified more trivially by compilers for
optimizations. e.g. Rather than shifting the halves of the value and
then swapping and combining them, we can swap them in place.
e.g. for the original swap32 code on x86-64, clang 8.0 would generate:
mov ecx, edi
rol cx, 8
shl ecx, 16
shr edi, 16
rol di, 8
movzx eax, di
or eax, ecx
ret
while GCC 8.3 would generate the ideal:
mov eax, edi
bswap eax
ret
now both generate the same optimal output.
MSVC used to generate the following with the old code:
mov eax, ecx
rol cx, 8
shr eax, 16
rol ax, 8
movzx ecx, cx
movzx eax, ax
shl ecx, 16
or eax, ecx
ret 0
Now MSVC also generates a similar, but equally optimal result as clang/GCC:
bswap ecx
mov eax, ecx
ret 0
====
In the swap64 case, for the original code, clang 8.0 would generate:
mov eax, edi
bswap eax
shl rax, 32
shr rdi, 32
bswap edi
or rax, rdi
ret
(almost there, but still missing the mark)
while, again, GCC 8.3 would generate the more ideal:
mov rax, rdi
bswap rax
ret
now clang also generates the optimal sequence for this fallback as well.
This is a case where MSVC unfortunately falls short, despite the new
code, this one still generates a doozy of an output.
mov r8, rcx
mov r9, rcx
mov rax, 71776119061217280
mov rdx, r8
and r9, rax
and edx, 65280
mov rax, rcx
shr rax, 16
or r9, rax
mov rax, rcx
shr r9, 16
mov rcx, 280375465082880
and rax, rcx
mov rcx, 1095216660480
or r9, rax
mov rax, r8
and rax, rcx
shr r9, 16
or r9, rax
mov rcx, r8
mov rax, r8
shr r9, 8
shl rax, 16
and ecx, 16711680
or rdx, rax
mov eax, -16777216
and rax, r8
shl rdx, 16
or rdx, rcx
shl rdx, 16
or rax, rdx
shl rax, 8
or rax, r9
ret 0
which is pretty unfortunate.
Allows the compiler to inform when the result of a swap function is
being ignored (which is 100% a bug in all usage scenarios). We also mark
them noexcept to allow other functions using them to be able to be
marked as noexcept and play nicely with things that potentially inspect
"nothrowability".
Including every OS' own built-in byte swapping functions is kind of
undesirable, since it adds yet another build path to ensure compilation
succeeds on.
Given we only support clang, GCC, and MSVC for the time being, we can
utilize their built-in functions directly instead of going through the
OS's API functions.
This shrinks the overall code down to just
if (msvc)
use msvc's functions
else if (clang or gcc)
use clang/gcc's builtins
else
use the slow path
The template type here is actually a forwarding reference, not an rvalue
reference in this case, so it's more appropriate to use std::forward to
preserve the value category of the type being moved.
Makes the return type consistently uniform (like the intrinsics we're
wrapping). This also conveniently silences a truncation warning within
the kernel multi_level_queue.
Since C++17, the introduction of deduction guides for locking facilities
means that we no longer need to hardcode the mutex type into the locks
themselves, making it easier to switch mutex types, should it ever be
necessary in the future.
Many of these functions are carried over from Dolphin (where they aren't
used anymore). Given these have no use (and we really shouldn't be
screwing around with OS-specific thread scheduler handling from the
emulator, these can be removed.
The function for setting the thread name is left, however, since it can
have debugging utility usages.
When #2247 was created, thread_queue_list.h was the only user of
boost-related code, however #2252 moved the page table struct into
common, which makes use of Boost.ICL, so we need to add the dependency
to the common library's link interface again.
We really don't need to pull in several headers of boost related
machinery just to perform the erase-remove idiom (particularly with
C++20 around the corner, which adds universal container std::erase and
std::erase_if, which we can just use instead).
With this, we don't need to link in anything boost-related into common.
This makes the class much more flexible and doesn't make performing
copies with classes that contain a bitfield member a pain.
Given BitField instances are only intended to be used within unions, the
fact the full storage value would be copied isn't a big concern (only
sizeof(union_type) would be copied anyways).
While we're at it, provide defaulted move constructors for consistency.
Moves local global state into the Impl class itself and initializes it
at the creation of the instance instead of in the function.
This makes it nicer for weakly-ordered architectures, given the
CreateEntry() class won't need to have atomic loads executed for each
individual call to the CreateEntry class.
Makes it consistent with the regular standard containers in terms of
size representation. This also gets rid of dependence on our own
type aliases, removing the need for an include.
The necessity of this parameter is dubious at best, and in 2019 probably
offers completely negligible savings as opposed to just leaving this
enabled. This removes it and simplifies the overall interface.
This is compromise for swap type being used in union. A union has deleted default constructor if it has at least one variant member with non-trivial default constructor, and no variant member of T has a default member initializer. In the use case of Bitfield, all variant members will be the swap type on endianness mismatch, which would all have non-trivial default constructor if default value is specified, and non of them can have member initializer
Original reason:
As Windows multi-byte character codec is unspecified while we always assume std::string uses UTF-8 in our code base, this can output gibberish when the string contains non-ASCII characters. ::OutputDebugStringW combined with Common::UTF8ToUTF16W is preferred here.
While admirable as a means to ensure immutability, this has the
unfortunate downside of making the class non-movable. std::move cannot
actually perform a move operation if the provided operand has const data
members (std::move acts as an operation to "slide" resources out of an
object instance). Given Barrier contains move-only types such as
std::mutex, this can lead to confusing error messages if an object ever
contained a Barrier instance and said object was attempted to be moved.
This is also unused and superceded by standard functionality. The
standard library provides std::this_thread::sleep_for(), which provides
a much more flexible interface, as different time units can be used with
it.
This is an old function that's no longer necessary. C++11 introduced
proper threading support to the language and a thread ID can be
retrieved via std::this_thread::get_id() if it's ever needed.
This is an analog of BitSet from Dolphin that was introduced to allow
iterating over a set of bits. Given it's currently unused, and given
that std::bitset exists, we can remove this. If it's ever needed in the
future it can be brought back.
Xbyak is currently entirely unused. Rather than carting it along, remove
it and get rid of a dependency. If it's ever needed in the future, then
it can be re-added (and likely be more up to date at that point in
time).
Currently, there's no way to specify if an assertion should
conditionally occur due to unimplemented behavior. This is useful when
something is only partially implemented (e.g. due to ongoing RE work).
In particular, this would be useful within the graphics code.
The rationale behind this is it allows a dev to disable unimplemented
feature assertions (which can occur in an unrelated work area), while
still enabling regular assertions, which act as behavior guards for
conditions or states which must not occur. Previously, the only way a
dev could temporarily disable asserts, was to disable the regular
assertion macros, which has the downside of also disabling, well, the
regular assertions which hold more sanitizing value, as opposed to
unimplemented feature assertions.
Currently, this was only performing a logging call, which doesn't
actually invoke any assertion behavior. This is unlike
UNIMPLEMENTED_MSG, which *does* assert.
This makes the expected behavior uniform across both macros.
