These forms were introduced in DWARF5, and have a fair deal of
advantages over the more traditional encodings: they reduce the size of
the binary and the number of relocations.
GCC does not emit these with `-g1` by default, but Clang does at all
debug levels.
This will be needed when we add `DW_FORM_strx*` and `DW_FORM_addrx*`
support, which requires us to fetch `DW_AT_str_offsets_base` and
`DW_AT_addr_base` attributes from the parent compilation unit. This
can't be done as we read the values, because it would create infinite
recursion (as we might try to parse the compilation unit's
`DW_FORM_strx*` encoded name before we get to the attribute). Having
getters ensures that we will perform lookups if they are needed.
Our Clang toolchain uses versioned names for its shared libraries,
meaning that our applications link against `libc++.so.1.0`, not simply
`libc++.so`. Without this change, the LLVM runtime libraries are
excluded from backtraces, which makes debugging toolchain issues harder.
The `wcsxfrm` function copies a wide character string into a buffer,
such that comparing the new string against any similarly pre-processed
string with `wcscmp` produces the same result as if the original strings
were compared with `wcscoll`.
Our current `wcscoll` implementation is simply an alias for `wcscmp`, so
`wcsxfrm` needs to perform no actions other than copying the string.
The ELAST macro is used on many systems to refer to the largest possible
valid errno value. LLVM's libc++ uses errno values of ELAST+1 and
ELAST+2 internally, and defines an arbitrary fallback value for
platforms which don't have the macro. This means that it's possible for
their internal errno numbers could coincide with values we actually use,
which would be a very bad thing.
Note our Attribute class is what the spec refers to as just "Attr". The
main differences between the existing implementation and the spec are
just that the spec defines more fields.
Attributes can contain namespace URIs and prefixes. However, note that
these are not parsed in HTML documents unless the document content-type
is XML. So for now, these are initialized to null. Web pages are able to
set the namespace via JavaScript (setAttributeNS), so these fields may
be filled in when the corresponding APIs are implemented.
The main change to be aware of is that an attribute is a node. This has
implications on how attributes are stored in the Element class. Nodes
are non-copyable and non-movable because these constructors are deleted
by the EventTarget base class. This means attributes cannot be stored in
a Vector or HashMap as these containers assume copyability / movability.
So for now, the Vector holding attributes is changed to hold RefPtrs to
attributes instead. This might change when attribute storage is
implemented according to the spec (by way of NamedNodeMap).
I originally implemented this as something to use the new sequence
wrapper, however, after having a look at uses with grep.app, it's used
often, for example:
- Bootstrap 5 Dropdowns
- Polymer
- Angular
- Closure
Previously, when the last layer got deleted, the active layer was
set to nullptr, causing a crash.
Now, we create a new transparent background layer with the image
dimensions instead.
We want to check the last SimpleSelector, not the first one. We don't
have to check that a SimpleSelector exists since a CompoundSelector
without one is invalid.
Also, renamed `builder` to `s` to match spec comments, and fixed a
find-and-replace typo where some pseudo-class names were
"last-of-pseudo_class" instead of "last-of-type".
This implements these algorithms from the CSSOM-1 spec:
- serialize a string
- serialize a URL
Also, we now have two versions of each of the serialization functions:
One that returns a String as before, and the other that takes a
StringBuilder to write into. This saves creating extra StringBuilders
when they are not needed. :^)
All its members are comparable themselves, so this can be defaulted.
Making it comparable will allow us, among other things, to check if a
list of symbols (i.e., the result of calling the symbolicate functions)
is equal or not to another, which in turn will allow us to avoid
refreshing the SystemMonitor's Stack tab when successive symbolicated
stacks are the same.
This function converts a single wide character into its multibyte
representation (UTF-8 in our case). It is called from libc++'s
`std::basic_ostream<wchar_t>::flush`, which gets called at program exit
from a global destructor in order to flush `std::wcout`.
