In order to reduce our reliance on __builtin_{ffs, clz, ctz, popcount},
this commit removes all calls to these functions and replaces them with
the equivalent functions in AK/BuiltinWrappers.h.
This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.
We already asked the region about what its library name is, and we also
use that value when maybe constructing a path, so let's make the check
use that as well.
Long doubles are always at least 80 bits wide in memory and it suffices
if we can address these 80 bits, to mark the long double as NAN at the
end of an MMX instruction, so the additional magic using conditional
types is unnecessary.
In the generated HTML code, '#' gets interpreted as the beginning of a
shell comment, which throws the syntax highlighting off. Regardless,
spelling out the meaning of the '#' might make it more readable.
We create a base class called GenericFramebufferDevice, which defines
all the virtual functions that must be implemented by a
FramebufferDevice. Then, we make the VirtIO FramebufferDevice and other
FramebufferDevice implementations inherit from it.
The most important consequence of rearranging the classes is that we now
have one IOCTL method, so all drivers should be committed to not
override the IOCTL method or make their own IOCTLs of FramebufferDevice.
All graphical IOCTLs are known to all FramebufferDevices, and it's up to
the specific implementation whether to support them or discard them (so
we require extensive usage of KResult and KResultOr, together with
virtual characteristic functions).
As a result, the interface is much cleaner and understandable to read.
This issue was also present in the kernel, the description of which is
provided in an identically titled commit.
Note that this couldn't have affected any programs running in
UserspaceEmulator as we don't support SSE instructions, and don't seem
to raise faults under any conditions.
We only froward String setting and FlagPost creation for now, due to the
other performance events being nonsensical to forward.
We also record these signposts in the optionally generated profile.
The kernel profiles were recently changed to have a `strings` array
as part of the profile objects. The `ProfileViewer` now checks for
that during startup and declares the profile invalid if the array
is not present.
The UserspaceEmulator doesn't use the API which the kernel exposed
the string array for, so just fake it by always adding an empty array
to the generated profiles.
The fact that profiles are json on one giant line makes them very
difficult to debug when things go wrong. Instead make sure to wrap
each event or sample on a newline so you can easily grep/heap/tail
the profile files.
It was fragile to use the address of the body of the memory management
functions to disable memory auditing within them. Functions called from
these did not get exempted from the audits, so in some cases
UserspaceEmulator reported bogus heap buffer overflows.
Memory auditing did not work at all on Clang because when querying the
addresses, their offset was taken relative to the base of `.text` which
is not the first segment in the `R/RX/RW(RELRO)/RW(non-RELRO)` layout
produced by LLD.
Similarly to when setting metadata about the allocations, we now use the
`emuctl` system call to selectively suppress auditing when we reach
these functions. This ensures that functions called from `malloc` are
affected too, and no issues occur because of the inconsistency between
Clang and GCC memory layouts.
Previously, we pushed the old `eip` on the stack before reading the new
address, which made us jump to the wrong place if the destination was
relative to the `esp`.
When printing a backtrace, each library's base address is found by
walking through all memory regions in the coredump, and selecting the
address of the first region whose name begins with the library's soname.
This is done to support the Clang toolchain, where .text is not at
offset 0.
However, because the libraries loaded by the emulated process used the
same names, we could not distinguish those with the ones used by
UserspaceEmulator, so the backtrace ended up being garbage.
Using the libraries mapped by UE would not be a sufficient, as the
running application could ask for other libraries too, and doing away
with setting names would make debugging issues within UE code more
difficult.
