Hi,
This year it's taken even longer than usual to get round to
posting the formal announcement, but here it now is, and there
has been a lot to sift through.
As of last month (27th April), [GCC 11.1 has now been
released](https://gcc.gnu.org/gcc-11/changes.html#d).
For the D language front-end, there have been a significant
number of changes, so it's probably best to start with the
lowlights as they are comparatively small.
---
Lowlights
---------
1. Contrary to the hopes of last years release announcement, this
version still uses [D
2.076.1](https://dlang.org/changelog/2.076.1.html) as the
baseline for D language support. Some significant blocking
issues in upstream DMD meant that I could not commit to switching
to self-hosted with full confidence, and said issues did not get
resolved until after the feature window closed.
2. The promise of dynamically generating D bindings from C
headers never really materialized. Actual work of adding a GCC
compiler switch to dump D code was [completed to around 95% of
what was
needed](https://github.com/D-Programming-GDC/gcc/compare/1cb2d1d5ce178cb68f0bd475299d2e0b25a4a756...ibuclaw/dumpspec), but then stalled on the just how this feature would integrate this into druntime.
Then there's been the announcement of importC, which seems
like a good reason to change tack and instead put effort into
getting importC to the state where it is fit for purpose.
Perhaps this utility could be released anyway, as an
alternative to the likes of DStep, except leverages gcc to parse
the sources instead via `gcc file.c -fdump-d-spec=file.d`
3. Whilst [my little project site](https://gdcproject.org) did
recent a styling revamp, very little was done in the way of
documentation. Though soon I hope to get changelog entries
published there at least.
4. The [compiler explorer site](https://explore.dgnu.org) has
also been updated, though the running compilers were left at
version GCC 9.1.
---
Highlights
----------
1. Instead of updating language version, efforts have been driven
towards increasing cross-platform support, there have been a
number of new additions:
- FreeBSD
- DragonFlyBSD
- OpenBSD
- OS X
- MinGW
OpenBSD, OS X and MinGW do not enable Phobos by default, and
are to be considered experimental at this time, you can override
the building of Phobos with the `--enable-libphobos` configure
switch. OS X has been the most tested of the experimental
configurations, and is working generally well on all versions
between Darwin 10 and 19.
2. Testing infrastructure has been expanded, and it is no longer
Ubuntu-centric. There are now the following new platforms under
test:
- [CirrusCI](https://cirrus-ci.com/build/6373685910044672)
- x86_64-linux-gnu
- x86_64-portbld-freebsd12.2
- x86_64-apple-darwin19
-
[Buildkite](https://buildkite.com/d-programming-gdc/gcc/builds/285)
- x86_64-alpine-linux-musl
- x86_64-unknown-netbsd
- amd64-unknown-openbsd6.9
For everything else under Buildkite, the two pre-existing
agents have had a CPU upgrade, and a third agent has been added
into the infrastructure that has reduced overall build times by
more than half. The servers I'm using for buildkite are
ridiculously cheap, however if you are interested in helping
support the monthly costs, you can do so by making a donation to
the [D Language
Foundation](https://dlang.org/foundation/donate.html),
approximations of costs into USD are up on my [Github Sponsor
page](https://github.com/sponsors/ibuclaw/).
---
**New features**:
- A new bottom type `typeof(*null)` has been added to represent
run-time errors and non-terminating functions. This also
introduces a new standard alias for the type named `noreturn`,
and is implicitly imported into every module.
- [Printf-like and
scanf-like](https://dlang.org/changelog/2.092.0.html#printfParams2) functions are now detected by prefixing them with pragma(printf) for printf-like functions or pragma(scanf) for scanf-like functions.
- The __traits() expression now supports the extensions
`isDeprecated`, `isDisabled`, `isFuture`, `isModule`,
`isPackage`, `child`, `isReturnOnStack`, `isZeroInit`,
`getTargetInfo`, `getLocation`, `hasPostblit`, `isCopyable`,
`getVisibility`, and `totype`.
- [An expression-based contract
syntax](https://dlang.org/changelog/2.081.0.html#expression-based_contract_syntax) has been added to the language.
- [Function literals can now
return](https://dlang.org/changelog/2.086.0.html#funcliteralsbyref) a value by reference with the `ref` keyword.
- [A new syntax is
available](https://dlang.org/changelog/2.087.0.html#aliasdecly_func) to declare aliases to function types using the `alias` syntax based on the assignment operator.
- [New
types](https://dlang.org/changelog/2.096.0.html#complex_types)
`__c_complex_float`, `__c_complex_double`, `__c_complex_real`,
and `__c_wchar_t` [have been
added](https://dlang.org/changelog/2.084.0.html#wchar_t) for
interfacing with C and C++ code, and are available from the
`core.stdc.config` module.
- [User-defined
attributes](https://dlang.org/changelog/2.082.0.html#enum_attributes) can now be used to annotate enum members, alias declarations, and function parameters.
- [Templates alias
parameters](https://dlang.org/changelog/2.087.0.html#template_alias_matches_basic_types) can now be instantiated with basic types such as `int` or `void function()`.
- The mixin construct can now be used as types in the form
`mixin(string) var`.
- The mixin construct can now take an argument list, same as
`pragma(msg)`.
**New intrinsics**:
- Bitwise rotate intrinsics `core.bitop.rol` and
`core.bitop.ror` have been added.
- Byte swap intrinsic `core.bitop.byteswap` for swapping bytes
in a 2-byte `ushort` has been added.
- Math intrinsics available from `core.math` now have overloads
for `float` and `double` types.
- Volatile intrinsics `core.volatile.volatileLoad` and
`core.volatile.volatileStore` have been moved from the
`core.bitop` module.
**New attributes**:
- The following GCC attributes are now recognized and available
from the `gcc.attributes` module with short-hand aliases for
convenience:
- `@attribute("alloc_size", arguments)` or
`@alloc_size(arguments)`.
- `@attribute("always_inline")` or `@always_inline`.
- `@attribute("used")` or `@used`.
- `@attribute("optimize", arguments)` or
`@optimize(arguments)`.
- `@attribute("cold")` or `@cold`.
- `@attribute("noplt")` or `@noplt`.
- `@attribute("target_clones", arguments)` or
`@target_clones(arguments)`.
- `@attribute("no_icf")` or `@no_icf`.
- `@attribute("noipa")` or `@noipa`.
- `@attribute("symver", arguments)` or `@symver(arguments)`.
- New aliases have been added to gcc.attributes for
compatibility with ldc.attributes.
- The `@allocSize(arguments)` attribute is the same as
`@alloc_size(arguments)`, but uses a 0-based index for function
arguments.
- The `@assumeUsed` attribute is an alias for
`@attribute("used")`.
- The `@fastmath` attribute is an alias for
`@optimize("Ofast")`.
- The `@naked` attribute is an alias for
`@attribute("naked")`. This attribute may not be available on all
targets.
- The `@restrict` attribute has been added to specify that a
function parameter is to be restrict-qualified in the C99 sense
of the term.
- The `@optStrategy(strategy)` attribute is an alias for
`@optimize("O0")` when the strategy is "none", otherwise
`@optimize("Os")` for the `"optsize"` and `"minsize"` strategies.
- The `@polly` attribute is an alias for
`@optimize("loop-parallelize-all")`.
- The `@section(name)` attribute is an alias for
`@attribute("section", name)`.
- The `@target(arguments)` attribute is an alias for
`@attribute("target", arguments)`.
- The `@weak` attribute is an alias for `@attribute("weak")`.
**New language options**:
- `-fweak-templates`, added to control whether declarations
that can be defined in multiple objects should be emitted as weak
symbols. The default is to emit all symbols with extern linkage
as weak, unless the target lacks support for weak symbols.
- `-Wdeprecated`, this option is now enabled by default.
- `-Wextra`, this option now turns on all warnings that are not
part of the core D language front-end - `-Waddress`,
`-Wcast-result`, `-Wunknown-pragmas`.
- `-Wvarargs`, added to turn on warnings about questionable
usage of the `va_start` intrinsic.
- *Deprecated and removed features*:
- Compiler-recognized attributes are now made available from
the `gcc.attributes` module, the former module `gcc.attribute`
has been deprecated and will be removed in a future release.
- The `@attribute("alias")` attribute has been removed, as it
had been superseded by `pragma(mangle)`.
- The `@attribute("forceinline")` attribute has been removed
and renamed to `@always_inline`.
- `__vector` types that are not supported in hardware are now
rejected at compile-time. Previously all vector types were
accepted by the compiler and emulated when target support was
absent.
- The `extern(Pascal)` linkage attribute [has been
removed](https://dlang.org/changelog/2.095.0.html#extern-pascal).
- [The deprecation
phase](https://dlang.org/changelog/2.087.0.html#remove_visibility) for `-ftransition=import` and `-ftransition=checkimports` is finished. These switches no longer have an effect and are now removed. Symbols that are not visible in a particular scope will no longer be found by the compiler.
- [It is now an
error](https://dlang.org/changelog/2.079.0.html#fix17630) to use
private variables selectively imported from other modules. Due to
a bug, some imported private members were visible from other
modules, violating the specification.
- The `-fweak` compiler switch has been removed, as it existed
only for testing.
---
GCC 12 Development
------------------
Now the development cycle has started again, I have ambitions for
a number disruptive changes to land during the next release
cycle, and this time I hope I really do mean it. :-)
1. Switch implementation of the compiler from C++ to D. Rebase
front-end with DMD master. Taking into account the alignment of
release cycles - and assuming that DMD releases don't loose their
cadence again - it would then be expected for GCC 12.1 to have
DMD 2.102.0-beta.1 or 2.102.0-rc.1. The GCC 12.2 release will
then have DMD 2.102.1, plus any other fixes that have gone into
stable before the master/stable merge.
2. ImportC is still too early to tell, but it might be an
interesting direction to steer in, so getting it to the point
where all druntime bindings in libc are replaced with C sources
would be the ambitious goal to acheive during this release cycle.
3. Begin hosting release binaries on the project site, update
compilers on the explorer site to version 11, and just more
generally keep adding to the build infrastruture.
There are - as always - more things to do than I have available
hours to do them in, but if this has pricked your interest, or
you feel you could help in any way, please don't hesitate to jump
on the [#gdc](https://dlang.slack.com/archives/C6LTP6MV1) channel
on the Dlang Slack or [#d.gdc](irc://irc.libera.chat/d.gdc) on
Libera.Chat IRC.
Until the next major/minor release...
Regards,
Iain.
