Adding an Array(Int32) field to a class breaks --release build

[ghost]

Crystal 0.26.1 (2018-09-27) LLVM: 6.0.1 Default target: x86_64-pc-linux-gnu

I am running Antergos (Arch Linux).

I have the following code:

require "sdl"

class Grid
  @rand = Random.new

  @grid : Array(Bool)
  @temp : Array(Bool)
  # @intensity : Array(Int32)

  def initialize(@grid_width : Int32, @grid_height : Int32)
    @grid = Array(Bool).new(@grid_width * @grid_height, false)
    @temp = Array(Bool).new(@grid.size, false)
    # @intensity = Array(Int32).new(@grid.size, 0)
    randomize
  end

  def randomize
    (0...@grid.size).each do |i|
      @grid[i] = @rand.next_bool
    end
  end
end

SDL.init(SDL::Init::VIDEO)
at_exit { SDL.quit }

window = SDL::Window.new("Life", 1280, 720)
renderer = SDL::Renderer.new(window, SDL::Renderer::Flags::ACCELERATED | SDL::Renderer::Flags::PRESENTVSYNC)
width, height = window.size

grid = Grid.new width, height

loop do
  case event = SDL::Event.poll
  when SDL::Event::Quit
    break
  when SDL::Event::Keyboard
    break
  end

  renderer.present
end

Here's my shard.yml:

name: life.cr
version: 0.1.0

authors:
  - Scitoshi Nakayobro <matthewtpeterson1@gmail.com>

targets:
  kitty_clicker:
    main: src/life.cr

dependencies:
    sdl:
        github: ysbaddaden/sdl.cr

crystal: 0.26.1

license: MIT

If I uncomment the two commented lines, the program compiles and 'runs', but the window never opens. This only happens on a release build; without --release, it works fine. I haven't been able to get any kind of error out of it thus far.

[jkthorne]

This might be a SDL bug. Have you tried adding logging to see if everything is still running?

[ghost]

The main loop is running, based on logging. What I can't understand is how this would be an SDL bug. I agree that it seems quite plausible given that the loop is still running, however, as far as I can tell based on the code, SDL and the Grid class have no interaction with each other, so I can't understand why adding that field would cause the window not to open.

[asterite]

The SDL bindings could be implemented in a wrong way. Mostly likely the struct's sizes are not the correct ones and so the stack memory is being overrun by something else and that causes the segmentation fault.

[ghost]

@asterite What segmentation fault? The program runs... it's just that the window doesn't open...

[ghost]

Just made an interesting discovery: putting a puts statement in the main loop (or above it) ALSO prevents the window from opening...

[asterite]

Ah, sorry, well, just incorrect behavior then.

[asterite]

I would open this issue in the SDL project/shard.

[ghost]

So it appears that the solution to this was to call window.update. The fact that the code works as is without --release makes me think that this is a compiler bug of some kind. Whether it be the Crystal compiler itself or an issue with LLVM... to me, the behavior should not change between debug and release builds.

[jhass]

Still reproduces using Crystal 0.29.0-dev [397bfe6e9]

[vlazar]

Works now. I see an empty black UI window when I run program.

Crystal 0.31.1 on MacOS

``` $ crystal --version Crystal 0.31.1 (2019-10-02) LLVM: 8.0.1 Default target: x86_64-apple-macosx ```

sdl2: stable 2.0.10

``` $ brew info sdl2 sdl2: stable 2.0.10 (bottled), HEAD Low-level access to audio, keyboard, mouse, joystick, and graphics https://www.libsdl.org/ /usr/local/Cellar/sdl2/2.0.10 (87 files, 4.6MB) * Poured from bottle on 2019-10-14 at 12:41:31 From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/sdl2.rb ==> Options --HEAD Install HEAD version ==> Analytics install: 67,239 (30 days), 193,676 (90 days), 789,026 (365 days) install_on_request: 7,547 (30 days), 20,950 (90 days), 85,555 (365 days) build_error: 0 (30 days) ```

[asterite]

Let's close this. It's. probably related to SDL bindings.