diff --git a/blog/vlang-update-2020-06-17.markdown b/blog/vlang-update-2020-06-17.markdown index f0fb253..0361288 100644 --- a/blog/vlang-update-2020-06-17.markdown +++ b/blog/vlang-update-2020-06-17.markdown @@ -1,260 +1,9 @@ --- -title: V Update - June 2020 +title: [removed] date: 2020-06-17 -series: v --- -# V Update - June 2020 +This post has been removed. I will learn from my mistakes that lead to this post +being authored and published. -Every so often I like to check in on the [V Programming Language][vlang]. It's been -about six months since [my last post](https://christine.website/blog/v-vvork-in-progress-2020-01-03), -so I thought I'd take another look at it and see what progress has been done in six -months. - -[vlang]: https://vlang.io - -Last time I checked, V 0.2 was slated for release in December 2019. It is currently -June 2020, and the latest release (at time of writing) is [0.1.27][vrelease0127]. - -## Feature Update - -Interestingly, the V author seems to have walked back one of their original -listed features of V and now has an [abstract syntax tree][ast] for representing the -grammar of the language. They still claim that functions are "pure" by default, but -allow functions to perform print statements while still being "pure". Printing data -to standard out is an impure side effect, but if you constrain the definition of -"side effects" to only include mutability of memory, this could be fine. - -[vrelease0127]: https://github.com/vlang/v/releases/tag/0.1.27 -[ast]: https://github.com/vlang/v/commit/093a025ebfe4f0957d5d69ad4ddcdc905a6d7b81#diff-5adb689a65970037f7f0ced3d4b9e800 - -The next stable release 0.2 seems to be planned for June 2020 (according to the readme); -and according to the todo list in the repo, memory management seems to be one of the -things that will be finished. V is also apparently in alpha, but will also apparently -jump from alpha directly to stable? - -## Build - -Testing V is a bit more difficult for me now as its build process is incompatible -with my Linux tower's [NixOS](https://nixos.org/nixos) install (I tend to try and -package all the programs I use for testing this stuff so it is easier to reproduce -my environment on other machines). The V scripts also do not work on my NixOS tower -because it doesn't have a `/usr/local/bin`. The correct way to make a shell script -cross-platform is to use the following header: - -```sh -#!/usr/bin/env v -``` - -This makes the `env` program search for the V binary in your `$PATH`, and will -function correctly on all platforms. - -The Makefile in the V source tree seems to do -network calls, specifically a `git clone`. Remember that this is on the front page -of the website: - -> V can be bootstrapped in under a second by compiling its code translated to C with a simple -> -> `cc v.c` -> -> No libraries or dependencies needed. - -Git is a dependency, which means perl is a dependency, which means a shell is a -dependency, which means glibc is a dependency, which means that a lot of other -things (including posix threads) are also dependencies. Pedantically, you could even -go as far as saying that you could count the Linux kernel, the processor being used -and the like as dependencies, but that's a bit out of scope for this. - -## Memory Management - -> V doesn't use garbage collection or reference counting. The compiler cleans -> everything up during compilation. If your V program compiles, it's guaranteed -> that it's going to be leak free. - -Amusingly, the documentation still claims that memory management is both a work in -progress and has perfect accuracy for cleaning up things at compile time. Let's run -my favorite test, the "how much ram do you leak compiling hello world" test. Last -it leaked `4,600,383` bytes (or about 4.6 megabytes) and before that it leaked -`3,861,785` bytes (or about 3.9 megabytes). This time: - -``` -$ valgrind ./v hello.v -==5413== Memcheck, a memory error detector -==5413== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. -==5413== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info -==5413== Command: ./v hello.v -==5413== -==5413== -==5413== HEAP SUMMARY: -==5413== in use at exit: 7,232,779 bytes in 163,690 blocks -==5413== total heap usage: 182,696 allocs, 19,006 frees, 11,309,504 bytes allocated -==5413== -==5413== LEAK SUMMARY: -==5413== definitely lost: 2,673,351 bytes in 85,739 blocks -==5413== indirectly lost: 4,265,809 bytes in 77,711 blocks -==5413== possibly lost: 256,000 bytes in 1 blocks -==5413== still reachable: 37,619 bytes in 239 blocks -==5413== suppressed: 0 bytes in 0 blocks -==5413== Rerun with --leak-check=full to see details of leaked memory -==5413== -==5413== For counts of detected and suppressed errors, rerun with: -v -==5413== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) -``` - -It seems that the memory managment really is a work in progress. This increase in -leakage means that the compiler building itself now creates `7,232,779` bytes of -leaked ram (which if i recall is actually a remarkable improvement). - -However, `hello world` seems to leak again: - -``` -$ valgrind ./hello -==13258== Memcheck, a memory error detector -==13258== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. -==13258== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info -==13258== Command: ./hello -==13258== -hello world -==13258== -==13258== HEAP SUMMARY: -==13258== in use at exit: 12,144 bytes in 14 blocks -==13258== total heap usage: 15 allocs, 1 frees, 13,168 bytes allocated -==13258== -==13258== LEAK SUMMARY: -==13258== definitely lost: 0 bytes in 0 blocks -==13258== indirectly lost: 0 bytes in 0 blocks -==13258== possibly lost: 0 bytes in 0 blocks -==13258== still reachable: 12,144 bytes in 14 blocks -==13258== suppressed: 0 bytes in 0 blocks -==13258== Rerun with --leak-check=full to see details of leaked memory -==13258== -==13258== For counts of detected and suppressed errors, rerun with: -v -==13258== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) -``` - -I'm not entirely sure how this happened, but here is the output of -`v -keepc hello.v`: https://git.io/Jfdsu. - -## Doom - -The [Doom](https://github.com/vlang/doom) translation project still has one file -translated (and apparently it breaks sound effects but not music). - -## 1.2 Million Lines of Code - -Let's re-run the artificial as heck 1.2 million lines of code benchmark from the -last post: - -``` -$ bash -c 'time ~/code/v/v main.v' - -real 7m54.847s -user 7m32.860s -sys 0m14.212s -``` - -This is a major improvement! It's cut at least 2 minutes off of the build time for -this incredibly contrived benchmark! Let's see how big the generated binary is: - -``` -$ du -hs ./main -179M ./main -``` - -This is identical to how big it was last time. Let's see how much ram it leaks: - -``` -$ valgrind ./main -==11773== Memcheck, a memory error detector -==11773== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. -==11773== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info -==11773== Command: ./main -==11773== -hello, 1 1! - -==11773== -==11773== HEAP SUMMARY: -==11773== in use at exit: 12,144 bytes in 14 blocks -==11773== total heap usage: 15 allocs, 1 frees, 13,168 bytes allocated -==11773== -==11773== LEAK SUMMARY: -==11773== definitely lost: 0 bytes in 0 blocks -==11773== indirectly lost: 0 bytes in 0 blocks -==11773== possibly lost: 0 bytes in 0 blocks -==11773== still reachable: 12,144 bytes in 14 blocks -==11773== suppressed: 0 bytes in 0 blocks -==11773== Rerun with --leak-check=full to see details of leaked memory -==11773== -==11773== For counts of detected and suppressed errors, rerun with: -v -==11773== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0) -``` - -About what I expected. - -## Concurrency - -A common problem that shows up when writing multi-threaded code are -[race conditions][races]. Effectively, race conditions are when two bits of code try -to do the same thing at the same time on the same block of memory. This leads to -undefined behavior, which is bad because it can corrupt or crash programs. - -[races]: https://en.wikipedia.org/wiki/Race_condition - -As an example, consider this program `raceanint.v`: - -``` -fn main() { - foo := [ 1 ] - go add(mut foo) - go add(mut foo) - - for {} -} - -fn add(mut foo []int) { - for { - foo[0] = foo[0] + 1 - } -} -``` - -In theory, this should have two threads infinitely trying to increment `foo[0]`, -which will eventually result in `foo[0]` getting corrupted by two threads trying to -do the same thing at the same time (given the tight loops invovled). - -However, I can't get this to build: - -``` -================== -/home/cadey/.cache/v/raceanint.tmp.c: In function ‘add_thread_wrapper’: -/home/cadey/.cache/v/raceanint.tmp.c:1209:6: error: incompatible type for argument 1 of ‘add’ - add(arg->arg1); - ^~~ -/home/cadey/.cache/v/raceanint.tmp.c:1198:13: note: expected ‘array_int * {aka struct array *}’ but argument is of type ‘array_int {aka struct array}’ - static void add(array_int* foo); - ^~~ -/home/cadey/.cache/v/raceanint.tmp.c: In function ‘strconv__v_sprintf’: -/home/cadey/.cache/v/raceanint.tmp.c:3611:7: warning: variable ‘th_separator’ set but not used [-Wunused-but-set-variable] - bool th_separator = false; - ^~~~~~~~~~~~ -/home/cadey/.cache/v/raceanint.tmp.c: In function ‘print_backtrace_skipping_top_frames_linux’: -... -================== -(Use `v -cg` to print the entire error message) - -builder error: -================== -C error. This should never happen. - -If you were not working with C interop, please raise an issue on GitHub: - -https://github.com/vlang/v/issues/new/choose -``` - -Like I said before, I also cannot file new issues about this. So if you are willing -to help me out, please open an issue about this. - ---- - -Overall, V looks like it is making about as much progress as I had figured it would. -I wish the team luck in their work! +I was in a bad mental state when I wrote this and it really shows.