Category Archives: News

DMD 2.089.0 Released

Digital Mars logoThe latest release of DMD, the D reference compiler, is ready for download. It’s a relatively light release in terms of changes and features, with 11 major changes and 66 closed Bugzilla issues. Most of the changes cover narrow use cases. To highlight a few: proper non-D mangling in template mixins, a renamed default linker, and expanded support in DUB for LDC.

Proper non-D mangling in template mixins

Maintainers of C bindings, or anyone writing D programs that need to interface with a custom C codebase, may find this change particularly useful. Previously, symbols declared as extern(C), extern(Windows)(which is stdcall), and extern(Objective-C) in template mixins were improperly mangled as D symbols when the templates were mixed in at global scope. It was easy to work around if you didn’t need parameterization (just use string mixins), but if you did need it, then you were either stuck or had to jump through hoops.

The root of the issue was that a template mixin introduces a new scope at the point it’s mixed in and creates aliases to the declarations inside that scope so that they may be accessed externally without the need for dot notation. This is a major convenience when only one instance of the template is mixed into a scope (as is the usual case) and allows for code to be written as if the template mixin doesn’t exist. In other words:

mixin template Foo(T)
{
    T x;
}

mixin Foo;

// Not required
// mixin Foo f;

// Allows this:
int main()
{
    x = 10;

    // Not required
    // f.x = 10;
}

The additional scope meant that, e.g., an extern(C) symbol in a template mixin was never in global scope, so it was mangled as a D symbol rather than a C symbol. With the change, such symbols are promoted from the mixin scope to the global scope and are properly mangled. Now you can choose either string mixins or template mixins for your C/stdcall /Objective-C boilerplate.

No more link.exe conflict

From the first alpha release of DMD, OPTLINK has been the default linker that ships with the compiler on Windows. When Walter Bright first started working on DMD, he used the existing C compiler backend he had been maintaining for 20 years. Since the backend already output object files in the Intel OMF format, he also decided to make use of OPTLINK; it had become a part of the C and C++ compiler package while he was at Borland. It was several years later that he added support Microsoft’s MSCOFF (PE) and the Microsoft linker, cl, to DMD. The fact that both the OPTLINK and cl executables were named link.exe wasn’t an issue early on, but over time it has begun to pop up more often, particularly when performing the compile and link steps separately.

With DMD 2.089, it will never be an issue again. The version of OPTLINK that ships with DMD has been renamed to optlink.exe.

DUB and LDC

DUB, the D build tool and package manager, has shipped with DMD for several releases. When executing dub on a properly configured source package, DMD is the default compiler. It also supports LDC (the LLVM-based D compiler) and GDC (the GCC-based D compiler, which is part of GCC 9) via command-line options, but the full range of DUB features haven’t been available for those compilers.

The latest version improves support for LDC. DUB command-line options to enable code coverage, profiling, keeping the stack frame, and separate linking now work with LDC. Target triples can be given to the --architecture (-a) switch to enable cross-compilation with LDC.

D Language Foundation Funding: New Platforms, New Bounties

Digital Mars logoWhen I first announced the HR Fund here on the blog back in April, there was talk among the D Language Foundation team of hiring one or more people to flesh out the specification and implementation of shared. That sort of work requires a very specific skillset that only a few people in the orbit of D possess. So far, we’ve been unable to find any of them with the time to spare. Meanwhile, the HR Fund is sitting there, waiting to be used.

Mobile Support for LDC

A few weeks ago, Ethan Watson wrote a post in the D forums titled, DMD or LDC on mobile. That thread, followed up by emails with Ethan and a few other people, presented a great opportunity to start putting the HR fund to use. Given that LDC already has support for ARM and DMD does not, it’s more practical to fund efforts on LDC than on DMD

As Adam Ruppe has suggested in the forums, he is currently working under contract to complete the existing work on Android support for LDC. By the time he’s finished, it should be possible for anyone to build a D application for Android and distribute it through the Play Store.

The iOS story, unfortunately, hasn’t yet moved forward. We had the ideal candidate on board and eager to get started, but he was sadly unable to get the time off from work that he would need to get the job done. We’ve asked around, looking for someone else with the same skillset to take on the task, but have come up empty. So now we’re reaching to the community at large. But with a twist…

New Task Bounties

Back in August, I announced that we had launched a new Bug Bounty system. The term “Bug” was perhaps too restrictive, so I’ve renamed the menu to Task Bounties. And as of today the D Language Foundation has seeded three new bounties: two for Bugzilla issues and one for the aforementioned LDC project.

Donate to the campaign for adding iOS/iPadOS support to LDC.

The D Language Foundation has put forward $3000 to seed the bounty to add iOS and iPadOS support to LDC. We encourage anyone interested in seeing this task complete to donate to increase the bounty.

This isn’t a typical bounty, as the money will only be paid as the result of contract work. As such, the money to seed it comes from the HR fund. So if you’re interested in taking the bounty home, click the image above and read the bounty description. We want to get this completed as soon as possible, else we’d wait for our original candidate to become available. So if you have the requisite knowledge, skills, and abilities to get the job done, please don’t hesitate to reach out.

The Foundation seeded two Bugzilla bounties (from the General Fund) at $50 each: one for issue #18472 (betterC: cannot use format at compile time) and the other for issue #18062 (ddoc: Generated .html files should retain the package hierarchy). Click through those links to increase the bounties, or visit Bugzilla #18472 or Bugzilla #18062 for the bug details to get started on fixing one.

I’d like to thank the members of the dlang-jp community for bringing these bugs to our attention. I recently met three of them in Tokyo along with Átila Neves. Aside from having a great time hanging out and touring part of Asakusa, we had a good chat about D and the Japanese D community. I look forward to the next opportunity to see them.

We’ll be seeding more Bugzilla bounties in the coming weeks. I’ll be digging into some of the old #dbugfix issues that are still open. If you have a bug that’s particularly troubling you, please consider seeding a bounty for it yourself. Alternatively, post a link to it on Twitter with the #dbugfix hashtag and we’ll consider the possibility of seeding a bounty with Foundation money.

Please visit the Task Bounties page to see if anything else there strikes your fancy!

The HR Fund Status

The HR Fund currently sits at $16,345. We’re about to lose some of it to Adam for his work on Android and (hopefully) more to someone who takes on the iOS task. Currently, we’re looking into other opportunities to put some of it to use. We still have dreams of funding major work, so we need to continue to make the HR Fund grow.

You can help us by donating to the HR Fund campaign directly, or by using our special $60 campaign: donate $60 to the HR Fund and get a DConf 2019 t-shirt. We still have several shirts available, scattered throughout the world, so please take one off of someone’s hands!

AmazonSmile

In a previous post, I mentioned the AmazonSmile plugins Smile Always for Chrome and Smart Amazon Smile for Firefox as easy ways to support the D Language Foundation. These plugins ensure that every time you visit amazon.com you will be sent to smile.amazon.com instead to support your selected charity. If its the D Language Foundation, we get 0.5% of every eligible purchase you make (and sorry to the international folks, but the D Language Foundation is only available as a charity through the .com domain).

Now, you can also support the D Language Foundation through the Amazon Shopping App for Android. Visit the AmazonSmile Mobile page to see how.

DMD 2.088.0 Released

Digital Mars logoThe newest DMD has rolled off the assembly line and is ready for download. A total of 58 contributors fixed 58 bugs and introduced 27 major changes to version 2.088.0 of the compiler.

I’m always looking for the big ticket items in a new DMD release to highlight on the blog, but this is a workaday release that isn’t showing off anything too shiny in the changleog. Much of it is run-of-the mill maintenance: deprecations, removals, and behavior adjustments. All of that is important, and we all welcome it, but it doesn’t make for great reading on the blog. That said, there are a handful of useful additions that I can point to, one of which actually is a big deal when it comes to C++ interop.

std::string and std::vector

Thanks to the work Manu Evans has been performing and advocating, C++ interoperability gets a big boost in this release with bindings to std::string and std::vector in the DRuntime modules core.stdcpp.string and core.stdcpp.vector, respectively.  There’s one caveat with the std::string binding that anyone intending to use it must be aware of.

When compiling on Linux, where DMD makes use of the GCC libraries and linker, there’s a compatibility issue when using the modern version of std::string which is compliant with C++11. It contains an interior pointer, which in D is both illegal and incompatible with move semantics. The work around is to pass -D_GLIBCXX_USE_CXX11_ABI=0 to g++ and compile your D application with -version=_GLIBCXX_USE_CXX98_ABI. This will be resolved in the future when work on move constructors in D is complete.

New Utilities

The language gets an interesting new compile-time trait in the form of getLocation. Given a symbol, this trait will return a tuple containing the file name, line number, and column number at which the symbol appears in the source code. This opens the door to more informative debug logging and error reporting beyond the functionality already available via __FILE__ and __LINE__. And I’m sure folks will find other uses for it.

The standard library utility module std.file, which provides a lot of convenience functions for working with files as a unit, now has the new function getAvailableDiskSpace. Give it a directory path on Windows, or the path to a directory or file on Posix, and it will give you the number of bytes available on that path.

Other News

The Symmetry Autumn of Code 2019 participants all have mentors now and they are hard at work laying out their milestones. Milestone 1 officially kicks off on September 15, after which we can expect to see weekly updates from the participants in the General forum.

Google Summer of Code 2019 has come to an end. Five of our students submitted their work at the end of August. You can find information about their projects and view their code submissions from our GSOC projects page. Congratulations to all who participated!

The D Language Foundation is currently in discussions to put some of the Human Resource Fund to use in finalizing LDC support for iOS and Android. Hopefully, I’ll have details to report on that front in the very near future. In the meantime, please help us raise the HR Fund even higher than it is now. There’s some important work waiting to be done that will require as much money as we can throw at it. You can donate any amount directly to the HR Fund Campaign or use the special campaign we set up to send $60 to the HR Fund and get a DConf 2019 t-shirt in return.

Speaking of t-shirts, thanks to everyone who has made a purchase in our DLang Swag Emporium. You’ve helped us raise over $77 so far, all of which will go to the General Fund. If you haven’t yet dropped in, what are you waiting for? We’ve got t-shirts, stickers, and coffee mugs, with updates coming soon. It’s an easy way to support our favorite programming language!

 

Updates in D Land

As we encroach upon the end of 2018, a recent Reddit thread wishing D a happy 17th birthday reminded me how far the language has come since I first stumbled upon it in 2003. Many of the steps along the way were powered by the energy of users who had little incentive to contribute beyond personal interest. And here we are, all these years later, still moving forward.

There are a number of current and upcoming happenings that will play a role in keeping that progress going. In this post, I’d like to remind you, update you, or inform you about some of them.

The Pull Request Manager Campaign

If you haven’t heard, the D Language Foundation has hired a pull request manager, to be paid out of a pool of donations. This is our first major fundraising campaign through Flipcause. I’m happy to report that it’s going well. As I write, we’ve raised $1,864 of our $3,000 target in 66 days thanks to the kindness of 30 supporters. If you’d like to support us in this cause, click on the campaign card.

You can access our full campaign menu at any time via the “Donate Now” button in the sidebar here on the blog. A pull request has also been submitted to integrate the menu into dlang.org’s donation page. Currently, we only have two campaigns (this one and the General Fund) but any future campaigns will be accessible through those menus.

Symmetry Autumn of Code

Earlier this year, Symmetry Investments partnered with the D Language Foundation to sponsor the Symmetry Autumn of Code (SAoC). Three participants were selected to work on D-related projects over the course of four months, with milestones to mark their progress. If you haven’t heard of it or had forgotten, you can read the details on the SAoC page here at the blog.

Unfortunately, one participant was unable to continue after the first milestone. The other two, whom we have come to refer to as the two Francescos, have each successfully completed three milestones and are in the home stretch, aiming for that final payment and free trip to DConf 2019.

Francesco Mecca is working on porting an old D1 GC to modern D, and Francesco Galla’ is busy adding HTTP/2 support the vibe-http library. Both have made significant progress and are on track to a successful SAoC. Read more about their projects in my previous SAoC update.

DIP Updates

I’ve received partial feedback on a decision regarding DIP 1013 (The Deprecation Process) and expect to hear the final verdict soon. As soon as I do, I’ll move Manu’s DIP 1016 (ref T accepts r-values) into the Formal Assessment stage for Walter and Andrei to consider.

I had intended to move Razvan’s Copy Constructor DIP into Community Review by now, as that is a high priority for Walter and Andrei. However, he’s been working out some more details so it’s not quite yet ready. So as not to hold up the process any longer, I’ll be starting Community Review for one of the other DIPs in the PR queue at the end of this week. When the Copy Constructor DIP is ready, I’ll run its review in parallel.

Google Summer of Code (GSoC) 2019

At the end of last month, I announced in the forums that we’re ramping up for GSoC 2019. I seeded our Wiki page with two potential project ideas to get us started. So far, only one additional idea has been added and no one has contacted me about participating as a student or a mentor.

It’s been a while since we were last accepted into GSoC and we’d very much like to get into it this time. To do so, we need more project ideas, students to execute them, and mentors to provide guidance to the students. If you’re looking for another way to contribute to the D community, this is a great way to do so. Adding project ideas costs little beyond the time it takes to add the details to the Wiki and, if you are lacking in ideas already dying to escape the confines of your neurocranium, the time it takes to brainstorm something. Student and mentor participation is a more significant commitment, but it’s also a lot more rewarding. If you’re interested, tell me at aldacron@gmail.com.

DConf 2019

Finally, I’m happy to announce… Just kidding. I can’t announce anything yet about DConf 2019, but I hope to be able to soon. What I can say with certainty is that in 2019, DConf will be where DConf has never gone before. We’re currently working out some details with an eye toward making 2019 a big year for DConf.

I’m really excited about it and eager to let everyone know. I’ll do so as soon as I’m able. Watch this space!

LDC 1.8.0 Released

LDC, the D compiler using the LLVM backend, has been actively developed for going on a dozen years, as laid out by co-maintainer David Nadlinger in his DConf 2013 talk. It is considered one of two production compilers for D, along with GDC, which uses the gcc backend and has been accepted for inclusion into the gcc tree.

The LDC developers are proud to announce the release of version 1.8.0, following a short year and a half from the 1.0 release. This version integrates version 2.078.3 of the D front-end (see the DMD 2.078.0 changelog for the important front-end changes), which is itself written in D, making LDC one of the most prominent mixed D/C++ codebases. You can download LDC 1.8.0 and read about the major changes and bug fixes for this release at GitHub.

More platforms

Kai Nacke, the other LDC co-maintainer, talked at DConf 2016 about taking D everywhere, to every CPU architecture that LLVM supports and as many OS platforms as we can. LDC is a cross-compiler: the same program can compile code for different platforms, in contrast to DMD and GDC, where a different DMD/GDC binary is needed for each platform. Towards that end, this release continues the existing Android cross-compilation support, which was introduced with LDC 1.4. A native LDC compiler to both build and run D apps on your Android phone is also available for the Termux Android app. See the wiki page for instructions on how to use one of the desktop compilers or the native compiler to compile D for Android.

The LDC team has also been putting out LDC builds for ARM boards, such as the Raspberry Pi 3. Download the armhf build if you want to try it out. Finally, some developers have expressed interest in using D for microservices, which usually means running in an Alpine container. This release also comes with an Alpine build of LDC, using the just-merged Musl port by @yshui. This port is brand new. Please try it out and let us know how well it works.

Linking options – shared default libraries

LDC now makes it easier to link with the shared version of the default libraries (DRuntime and the standard library, called Phobos) through the -link-defaultlib-shared compiler flag. The change was paired with a rework of linking-related options. See the new help output:

Linking options:

-L= - Pass to the linker
-Xcc= - Pass to GCC/Clang for linking
-defaultlib=<lib1,lib2,…> - Default libraries to link with (overrides previous)
-disable-linker-strip-dead - Do not try to remove unused symbols during linking
-link-defaultlib-debug - Link with debug versions of default libraries
-link-defaultlib-shared - Link with shared versions of default libraries
-linker=<lld-link|lld|gold|bfd|…> - Linker to use
-mscrtlib=<libcmt[d]|msvcrt[d]> - MS C runtime library to link with
-static

Other new options

  • -plugin=... for compiling with LLVM-IR pass plugins, such as the AFLfuzz LLVM-mode plugin
  • -fprofile-{generate,use} for Profile-Guided Optimization (PGO) based on the LLVM IR code (instead of PGO based on the D abstract syntax tree)
  • -fxray-{instrument,instruction-threshold} for generating code for XRay instrumentation
  • -profile (LDMD2) and -fdmd-trace-functions (LDC2) to support DMD-style profiling of programs

Vanilla compiler-rt libraries

LDC uses LLVM’s compiler-rt runtime library for Profile-Guided Optimization (PGO), Address Sanitizer, and fuzzing. When PGO was first added to LDC 1.1.0, the required portion of compiler-rt was copied to LDC’s source repository. This made it easy to ship the correct version of the library with LDC, and make changes for LDC specifically. However, a copy was needed for each LLVM version that LDC supports (compiler-rt is compatible with only one LLVM version): the source of LDC 1.7.0 has 6 (!) copies of compiler-rt’s profile library.

For the introduction of ASan and libFuzzer in the official LDC binary packages, a different mechanism was used: when building LDC, we check whether the compiler-rt libraries are available in LLVM’s installation and, if so, copy them into LDC’s lib/ directory. To use the same mechanism for the PGO runtime library, we had to remove our additions to that library. Although the added functionality is rarely used, we didn’t want to just drop it. Instead, the functionality was turned into template-only code, such that it does not need to be compiled into the library (if the templated functionality is called by the user, the template’s code will be generated in the caller’s object file).

With this change, LDC no longer needs its own copy of compiler-rt’s profile library and all copies were removed from LDC’s source repository. LDC 1.8.0 ships with vanilla compiler-rt libraries. LDC’s users shouldn’t notice any difference, but for the LDC team it means less maintenance burden.

Onward

A compiler developer’s work is never done. With this release out the door, we march onward toward 1.9. Until then, start optimizing your D programs by downloading the pre-compiled LDC 1.8.0 binaries for Linux, Mac, Windows, Alpine, ARM, and Android, or build the compiler from source from our GitHub repository.

Thanks to LDC contributors Johan Engelen and Joakim for coauthoring this post.

DMD 2.079.0 Released

The D Language Foundation is happy to announce version 2.079.0 of DMD, the reference compiler for the D programming language. This latest version is available for download in multiple packages. The changelog details the changes and bugfixes that were the product of 78 contributors for this release.

It’s not always easy to choose which enhancements or changes from a release to highlight on the blog. What’s important to some will elicit a shrug from others. This time, there’s so much to choose from that my head is spinning. But two in particular stand out as having the potential to result in a significant impact on the D programming experience, especially for those who are new to the language.

No Visual Studio required

Although it has only a small entry in the changelog, this is a very big deal for programming in D on Windows: the Microsoft toolchain is no longer required to link 64-bit executables. The previous release made things easier by eliminating the need to configure the compiler; it now searches for a Visual Studio or Microsoft Build Tools installation when either -m32mscoff or -m64 are passed on the command line. This release goes much further.

DMD on Windows now ships with a set of platform libraries built from the MinGW definitions and a wrapper library for the VC 2010 C runtime (the changelog only mentions the installer, but this is all bundled in the zip package as well). When given the -m32mscoff or -m64 flags, if the compiler fails to find a Windows SDK installation (which comes installed with newer versions of Visual Studio – with older versions it must be installed separately), it will fallback on these libraries. Moreover, the compiler now ships with lld, the LLVM linker. If it fails to find the MS linker, this will be used instead (note, however, that the use of this linker is currently considered experimental).

So the 64-bit and 32-bit COFF output is now an out-of-the-box experience on Windows, as it has always been with the OMF output (-m32, which is the default). This should make things a whole lot easier for those coming to D without a C or C++ background on Windows, for some of whom the need to install and configure Visual Studio has been a source of pain.

Automatically compiled imports

Another trigger for some new D users, particularly those coming from a mostly Java background, has been the way imports are handled. Consider the venerable ‘Hello World’ example:

import std.stdio;

void main() {
    writeln("Hello, World!");
}

Someone coming to D for the first time from a language that automatically compiles imported modules could be forgiven for assuming that’s what’s happening here. Of course, that’s not the case. The std.stdio module is part of Phobos, the D standard library, which ships with the compiler as a precompiled library. When compiling an executable or shared library, the compiler passes it on to the linker along any generated object files.

The surprise comes when that same newcomer attempts to compile multiple files, such as:

// hellolib.d
module hellolib;
import std.stdio;

void sayHello() {
    writeln("Hello!");
}

// hello.d
import hellolib;

void main() {
    sayHello();
}

The common mistake is to do this, which results in a linker error about the missing sayHello symbol:

dmd hello.d

D compilers have never considered imported modules for compilation. Only source files passed on the command line are actually compiled. So the proper way to compile the above is like so:

dmd hello.d hellolib.d

The import statement informs the compiler which symbols are visible and accessible in the current compilation unit, not which source files should be compiled. In other words, during compilation, the compiler doesn’t care whether imported modules have already been compiled or are intended to be compiled. The user must explicitly pass either all source modules intended for compilation on the command line, or their precompiled object or library files for linking.

It’s not that adding support for compiling imported modules is impossible. It’s that doing so comes with some configuration issues that are unavoidable thanks to the link step. For example, you don’t want to compile imported modules from libFoo when you’re already linking with the libFoo static library. This is getting into the realm of build tools, and so the philosophy has been to leave it up to build tools to handle.

DMD 2.079.0 changes the game. Now, the above example can be compiled and linked like so:

dmd -i hello.d

The -i switch tells the compiler to treat imported modules as if they were passed on the command line. It can be limited to specific modules or packages by passing a module or package name, and the same can be excluded by preceding the name with a dash, e.g.:

dmd -i=foo -i=-foo.bar main.d

Here, any imported module whose fully-qualified name starts foo will be compiled, unless the name starts with foo.bar. By default, -i means to compile all imported modules except for those from Phobos and DRuntime, i.e.:

-i=-core -i=-std -i=-etc -i=-object

While this is no substitute for a full on build tool, it makes quick tests and programs with no complex configuration requirements much easier to compile.

The #dbugfix Campaign

On a related note, last month I announced the #dbugfix Campaign. The short of it is, if there’s a D Bugzilla issue you’d really like to see fixed, tweet the issue number along with #dbugfix, or, if you don’t have a Twitter account or you’d like to have a discussion about the issue, make a post in the General forum with the issue number and #dbugfix in the title. The core team will commit to fixing at least two of those issues for a subsequent compiler release.

Normally, I’ll collect the data for the two months between major compiler releases. For the initial batch, we’re going three months to give people time to get used to it. I anticipated it would be slow to catch on, and it seems I was right. There were a few issues tweeted and posted in the days after the announcement, but then it went quiet. So far, this is what we have:

DMD 2.080.0 is scheduled for release just as DConf 2018 kicks off. The cutoff date for consideration during this run will be the day the 2.080.0 beta is announced. That will give our bugfixers time to consider which bugs to work on. I’ll include the tally and the issues they select in the DMD release announcement, then they will work to get the fixes implemented and the PRs merged in a subsequent release (hopefully 2.081.0). When 2.080.0 is released, I’ll start collecting #dbugfix issues for the next cycle.

So if there’s an issue you want fixed that isn’t on that list above, put it out there with #dbugfix! Also, don’t be shy about retweeting #dbugfix issues or +1’ing them in the forums. This will add weight to the consideration of which ones to fix. And remember, include an issue number, otherwise it isn’t going to count!

The State of D 2018 Survey

NOTE: The survey is closed. Thanks to everyone who participated!


Strange things are afoot at the D Language Foundation. Odd noises and varicolored lights have been reported emanating from the cellar into the wee hours of the morning. Foundation members have been sighted, stumbling dazed and bleary-eyed in and out of the front door, arms full of mysterious black boxes. Neighbors whisper, and rumor has it that the spawn of so much secretive activity is only one arcane ritual away from seeing the light of day.

How right they are! For the past few weeks, the initiate Sebastian Wilzbach has devoted his energies to studying the Book of Modern Arcana in preparation for the ritual known as the State of D 2018 Survey. With feedback from those already steeped in the Dark arts, he has been refining the incantations of the ritual so that they prove most effective. Now, at long last, his preparations are complete and the ritual has been unleashed upon the world!

Upon the D community anyway.

And now it’s on you. This is your chance to turn your praise, complaints, and nitpicks into action. By participating in the State of D survey, you’ll be providing guidance to the D Language Foundation to help identify both short and long-term goals for the future development of D and its ecosystem.

A handful of initiatives are already coming together in the cellar. You’ll be able to read about them in more detail here as they are announced in the coming days, weeks, and months. The 2018 H1 document, presenting an overview of the current focus, will be announced soon. This survey will help build on existing plans, fill in the details of the general goals, and identify any course corrections that are necessary for 2018 H2 and beyond.

The Foundation is eager to address the issues that matter most to the community. Members frequently make their thoughts known in the forums, but the conversations can be long, sprawling, wandering, and hard to follow. The State of D Survey will allow the core team to see at a glance what’s going right and what’s not, and to focus their attention where it’s needed most. It could take 15 minutes or more of your time to complete, depending on the amount of thought you put into your answers. If you care about the D programming language, it’s well worth every minute.

We’ll leave the survey open for at least two weeks. A short while after it closes, we’ll publish the results here. From then on, the blog will cover what’s happening in response, providing updates on progress at reasonable intervals. Then next year we’ll do it all again.

Remember, D is a community-driven language, but not everyone is able to contribute as much as they would like. Whether you’re a frequent contributor or just getting started writing D programs, this is your chance to help make D an even better language than it is today.

Make your opinion count and take the survey!

The #dbugfix Campaign

Why so many bugs?

Every major release of DMD comes with a list of closed issues from Bugzilla. For example, looking at the changelog for DMD 2.078.0 shows the following counts for closed regressions, bugs, and enhancements: 51 for the compiler, 37 for the standard library, 6 for the runtime, 17 for the website, and 1 for the linker. That’s 112 total issues, the majority related to the compiler. The total number of closed issues fluctuates between releases, but the compiler and standard library normally get the lion’s share.

This isn’t news to anyone who regularly follows DMD releases. But spend enough time on the forums and you’ll eventually see someone under the impression that bugs aren’t getting fixed. They cite the number of open issues in the database, or the age of some of the open issues, or the fact that they can’t find any formal process for fixing bugs. In reaction, it’s easy to point to the changelogs, or cite the number of closed issues in the database, or bring up the number of open issues in other language compilers. And, of course, to explain once again that this is a volunteer community where people work on the things that matter to them, and organizing groups to complete specific tasks is like herding cats.

That’s all quite reasonable, but really isn’t going to matter to someone who found the motivation to check D out, but is still looking for the motivation to stay. For me personally, I really don’t care how many issues are in the database, or the age of the oldest. All I care about is that it works for me. But I’m already invested in D. I don’t need to be motivated to stick around. And while I wouldn’t use a bug database as criteria to judge a new language, I can see that others do. It’s akin to looking at a stable repository on GitHub and dismissing it as abandoned because of its lack of recent activity. If you don’t see the whole picture, you can’t make an informed judgement.

If perception were the only issue, then it would simply be a matter of web design and PR. However, there have been, and are, people invested in D who have become frustrated because issues they reported, or that directly affect them, have languished in Bugzilla for months or even years. This can’t simply be dismissed as not seeing the whole picture. This is a matter of manpower and process. A number of issues are still open because there isn’t a simple fix, or perhaps because no one has taken an interest. The set of people who can solve complex issues is small. The set of people willing to work on issues that aren’t interesting to them is smaller. But again, how do you get a disparate group of volunteers of varying skill levels to devote their free time to fixing other peoples’ problems?

This is something the D community has struggled with as it has grown. There are no easy, comprehensive solutions without a full-time team of dedicated personnel, something we simply don’t have. However, it’s possible that there are opportunities to take baby steps and chip away at some of these issues without the complications inherent in herding cats.

The #dbugfix campaign

To recap, there are two primary complaints about the D bug-fixing process (such as it is):

  • Too many (old) bugs in the database
  • Bugs you care about aren’t getting fixed

In an effort to alleviate these problems, one baby step to chip away at it, I’m announcing the #dbugfix campaign.

It works like this. If there is an issue in D’s Bugzilla that you want to see fixed, whatever the reason (maybe it’s blocking you, or it’s annoying you, or it’s an enhancement you want, or you think it’s too old – it doesn’t matter), then either tweet out the issue number with #dbugfix in the tweet, or create a topic in the general forum with the issue number and #dbugfix in the subject line. I’ll monitor both Twitter and the forums and keep a running tally of issue numbers.

A week before a major version of DMD is released (starting with 2.080.0, which is slated for May 1), I’ll look at the tally and find the top five issues. I’ve already gotten people to commit to fixing at least two of the top five. That doesn’t mean only two. It could well be more. It depends on the complexity of the issues and how many other volunteers we can scrounge up. Hopefully, the two (or more) fixed bugs will be ready to be merged in the subsequent major release.

In the blog post announcing each major release, I’ll report on which bugs in the current release were fixed as a result of the campaign and announce the two selected for the subsequent release. If any of the top five from the previous release were not fixed, I’ll call for volunteers to help so that they can be squashed as soon as possible.

Yes, I know. We enabled voting on Bugzilla issues and that didn’t change anything. That’s because there was no real commitment to fixing any of the highest-voted issues. The votes simply served a guideline for the people browsing the database, looking for issues to fix. For this campaign, there really are people committed to fixing at least two of the issues that float to the top for every major release.

But two is not a lot! No, it isn’t. But it also isn’t zero. As I mentioned at the top of this post, dozens of issues are already fixed with each major DMD release. The problem (for those who see it as such) is that there’s currently next to zero community involvement in deciding which issues get fixed. This campaign gives the community more input into the selection process and it provides public updates on the status of that process. It is my hope that, in addition to changing perception and chipping away at the bug count, it encourages more people to help fix bugs.

If you would like to volunteer your time and knowledge to helping out with this campaign and increase the number of #dbugfix bugs fixed in each release, please email me at aldacron@gmail.com. For everyone else, I’ve got a search for #dbugfix set up in my Twitter client, so start tweeting!

DConf 2018: Register Now!

It was the middle of November when DConf 2018 was announced here on this blog in a Q & A session with Andrei Alexandrescu. Since then, the DConf train has slowly been building up steam as things have been happening behind the scenes. Now it’s full steam ahead!

 

The venue

DConf 2018 is being hosted at the NH München Messe hotel. They’re offering a discount (single room, breakfast included) to all conference attendees. If you’d like to cut out the commute time between your hotel and DConf, everything you need to take advantage of the discount and get to the hotel is over at the DConf 2018 venue page.

The registration fees

The cost of general admission to DConf 2018 is US $400. A 15% early-bird discount is available from now until March 17. This year, there’s a special deal for past attendees. If you signed up for DConf 2017, the 15% discount doesn’t go away in March. For you, it applies right up to the regular registration deadline. Whenever you’re ready to sign up, head on over to the DConf 2018 registration page where you can pay via PayPal or Eventbrite.

The invited keynote speaker

The D Language Foundation is excited to announce that Martin Odersky, the inventor of the Scala language, a professor at EPFL in Lausanne, Switzerland, and a founder of Lightbend, is this year’s invited keynote speaker. He’ll be presenting a talk titled, “How to Abstract Over Context”, in which he’ll “argue that implicit parameters as they are found in Scala are a canonical way to express context and that implicit function types are the right way to abstract over it.” We’re looking forward to it!

The partners

The time around, the conference is being hosted by QA Systems, a provider of tools for automating unit testing, code coverage, integration testing, and static analysis, in conjunction with HLMC, a company specialized in the organization of IT events. They’re working hard to ensure DConf 2018 is a success. We know it will be.

The call for submissions

Don’t forget, we’re taking submissions for D-language related papers, talks, demos, panels, and research reports until February 25. We’re eager to hear about what’s happening out there in the world of the D programming language. Put your proposal together and send it to foundation@dlang.org for consideration. If you’ve never submitted to DConf before, please give the guidelines a look over before you do so.

The uninitiated

We’re eager to see new faces this year, especially those who know little or nothing about the D programming language. If you or someone you know hasn’t yet figured out what all the fuss is about, we want a chance to show you. The D language community are a friendly bunch, happy to partake in engaging and intelligent conversation well into the night. And we love to meet new people! Every DConf is a chance to reinforce old bonds and forge new ones. You may arrive as a stranger, but you’ll leave as a friend.

The months ahead

As May 2 draws closer, keep an eye on this blog for more DConf 2018 updates, including posts from our partners, scheduled speakers, and the D Language Foundation.

DMD 2.078.0 Has Been Released

Another major release of DMD, this time 2.078.0, has been packaged and delivered in time for the new year. See the full changelog at dlang.org and download the compiler for your platform either from the main download page or the 2.078.0 release directory.

This release brings a number of quality-of-life improvements, fixing some minor annoyances and inconsistencies, three of which are targeted at smoothing out the experience of programming in D without DRuntime.

C runtime construction and destruction

D has included static constructors and destructors, both as aggregate type members and at module level, for most of its existence. The former are called in lexical order as DRuntime goes through its initialization routine, and the latter are called in reverse lexical order as the runtime shuts down. But when programming in an environment without DRuntime, such as when using the -betterC compiler switch, or using a stubbed-out runtime, static construction and destruction are not available.

DMD 2.078.0 brings static module construction and destruction to those environments in the form of two new pragmas, pragma(crt_constructor) and pragma(crt_destructor) respectively. The former causes any function to which it’s applied to be executed before the C main, and the latter after the C main, as in this example:

crun1.d

// Compile with:    dmd crun1.d
// Alternatively:   dmd -betterC crun1.d

import core.stdc.stdio;

// Each of the following functions should have
// C linkage (cdecl).
extern(C):

pragma(crt_constructor)
void init()
{
    puts("init");
}

pragma(crt_destructor)
void fini()
{
    puts("fini");
}

void main()
{
    puts("C main");
}

The compiler requires that any function annotated with the new pragmas be declared with the extern(C) linkage attribute. In this example, though it isn’t required, main is also declared as extern(C). The colon syntax on line 8 applies the attribute to every function that follows, up to the end of the module or until a new linkage attribute appears.

In a normal D program, the C main is the entry point for DRuntime and is generated by the compiler. When the C runtime calls the C main, the D runtime does its initialization, which includes starting up the GC, executing static constructors, gathering command-line arguments into a string array, and calling the application’s main function, a.k.a. D main.

When a D module’s main is annotated with extern(C), it essentially replaces DRuntime’s implementation, as the compiler will never generate a C main function for the runtime in that case. If -betterC is not supplied on the command line, or an alternative implementation is not provided, DRuntime itself is still available and can be manually initialized and terminated.

The example above is intended to clearly show that the crt_constructor pragma will cause init to execute before the C main and the crt_destructor causes fini to run after. This introduces new options for scenarios where DRuntime is unavailable. However, take away the extern(C) from main and the same execution order will print to the command line:

crun2.d

// Compile with:    dmd crun2.d

import core.stdc.stdio;

pragma(crt_constructor)
extern(C) void init()
{
    puts("init");
}

pragma(crt_destructor)
extern(C) void fini()
{
    puts("fini");
}

void main()
{
    import std.stdio : writeln;
    writeln("D main");
}

The difference is that the C main now belongs to DRuntime and our main is the D main. The execution order is: init, C main, D main, fini. This means init is effectively called before DRuntime is initialized and fini after it terminates. Because this example uses the DRuntime function writeln, it can’t be compiled with -betterC.

You may discover that writeln works if you import it at the top of the module and substitute it for puts in the example. However, always remember that even though DRuntime may be available, it’s not in a valid state when a crt_constructor and a crt_destructor are executed.

RAII for -betterC

One of the limitations in -betterC mode has been the absence of RAII. In normal D code, struct destructors are executed when an instance goes out of scope. This has always depended on DRuntime, and since the runtime isn’t available in -betterC mode, neither are struct destructors. With DMD 2.078.0, the are in the preceding sentence becomes were.

destruct.d

// Compile with:    dmd -betterC destruct.d

import core.stdc.stdio : puts;

struct DestroyMe
{
    ~this()
    {
        puts("Destruction complete.");
    }
}

extern(C) void main()
{
    DestroyMe d;
}

Interestingly, this is implemented in terms of try..finally, so a side-effect is that -betterC mode now supports try and finally blocks:

cleanup1.d

// Compile with:    dmd -betterC cleanup1.d

import core.stdc.stdlib,
       core.stdc.stdio;

extern(C) void main()
{
    int* ints;
    try
    {
        // acquire resources here
        ints = cast(int*)malloc(int.sizeof * 10);
        puts("Allocated!");
    }
    finally
    {
        // release resources here
        free(ints);
        puts("Freed!");
    }
}

Since D’s scope(exit) feature is also implemented in terms of try..finally, this is now possible in -betterC mode also:

cleanup2.d

// Compile with: dmd -betterC cleanup2.d

import core.stdc.stdlib,
       core.stdc.stdio;

extern(C) void main()
{
    auto ints1 = cast(int*)malloc(int.sizeof * 10);
    scope(exit)
    {
        puts("Freeing ints1!");
        free(ints1);
    }

    auto ints2 = cast(int*)malloc(int.sizeof * 10);
    scope(exit)
    {
        puts("Freeing ints2!");
        free(ints2);
    }
}

Note that exceptions are not implemented for -betterC mode, so there’s no catch, scope(success), or scope(failure).

Optional ModuleInfo

One of the seemingly obscure features dependent upon DRuntime is the ModuleInfo type. It’s a type that works quietly behind the scenes as one of the enabling mechanisms of reflection and most D programmers will likely never hear of it. That is, unless they start trying to stub out their own minimal runtime. That’s when linker errors start cropping up complaining about the missing ModuleInfo type, since the compiler will have generated an instance of it for each module in the program.

DMD 2.078.0 changes things up. The compiler is aware of the presence of the runtime implementation at compile time, so it can see whether or not the current implementation provides a ModuleInfo declaration. If it does, instances will be generated as appropriate. If it doesn’t, then the instances won’t be generated. This makes it just that much easier to stub out your own runtime, which is something you’d want to do if you were, say, writing a kernel in D.

Other notable changes

New users of DMD on Windows will now have an easier time getting a 64-bit environment set up. It’s still necessary to install the Microsoft build tools, but now DMD will detect the installation of either the Microsoft Build Tools package or Visual Studio at runtime when either -m64 or -m32mscoff is specified on the command line. Previously, configuration was handled automatically only by the installer; manual installs had to be configured manually.

DRuntime has been enhanced to allow more fine-grained control over unit tests. Of particular note is the --DRT-testmode flag which can be passed to any D executable. With the argument "run-main", the current default, any unit tests present will be run and then main will execute if they all pass; with "test-or-main", the planned default beginning with DMD 2.080.0, any unit tests present will run and the program will exit with a summary of the results, otherwise main will execute; with "test-only", main will not be executed, but test results will still be summarized if present.

Onward into 2018

This is the first DMD release of 2018. We can’t wait to see what the next 12 months bring for the D programming language community. From everyone at the D Language Foundation, we hope you have a very Happy New Year!