Folkert de Vries folkertdev

Using setjmp/longjmp in LLVM IR

Using the setjmp and longjmp LLVM instrinsics did not work as expected. There is an undocumented difference between the C implementation and the LLVM intrinsics.

setjmp/longjmp in C

setjmp/longjmp (sjlj for short) is a mechanism in C that is used to handle errors, potentially deep in the call stack.

With setjmp, the current stack frame is saved to some location in memory. Then down the line a lngjmp can jump back to where setjmp was called. The stack is then restored, and the return value of the setjmp call is different between the first call, when normal execution brought use there, and a subsequent call that is the result of a jump. The different return value allows us to distinguish how we got to the setjmp and act accordingly.

	use std::io::{Error, ErrorKind};

	use std::net::{IpAddr, Ipv4Addr, SocketAddr, UdpSocket};
	use std::os::unix::io::AsRawFd;

	use tokio::io::unix::AsyncFd;
	use tokio::io::Interest;

	pub(crate) fn cerr(t: libc::c_int) -> std::io::Result<libc::c_int> {
	match t {

	let mapleader=","

	" unset the mouse
	set mouse=

	au BufRead,BufNewFile *.elm set filetype=elm

	" copy to system clipboard
	" see http://askubuntu.com/questions/347519/unable-to-copy-from-vim-to-system-clipboard
	set clipboard=unnamedplus

	#[repr(C)]
	#[derive(Default)]
	struct ethtool_ts_info {
	cmd: u32,
	so_timestamping: u32,
	phc_index: u32,
	tx_types: u32,
	tx_reserved: [u32; 3],
	rx_filters: u32,
	rx_reserved: [u32; 3],

	program {
	mod "UserApp" {
	type "jY\xe2\xcd\xd2\xfd/t" = type_10 where {
	type type_0 = "UserApp"::"jY\xe2\xcd\xd2\xfd/t";
	type type_1 = "UserApp"::"jY\xe2\xcd\xd2\xfd/t";
	type type_2 = (type_0, type_1);
	type type_3 = ();
	type type_4 = (type_3);
	type type_5 = heap_cell;
	type type_6 = (type_5);

	[package]
	name = "wasmer-bug"
	version = "0.1.0"
	edition = "2018"

	# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

	[dependencies]
	wasmer = "2.0.0"
	wasmer-wasi = "2.0.0"

	float cubic_interpolate(
	float p0, float p1, float p2, float p3, float ratio, float cubic_coeff_a) {

	float cca = cubic_coeff_a;

	float coeffects_0 = ((cca * (ratio + 1) - 5 * cca) * (ratio + 1) + 8 * cca) * (ratio + 1) - 4 * cca;
	float coeffects_1 = ((cca + 2) * ratio - (cca + 3)) * ratio * ratio + 1;
	float coeffects_2 = ((cca + 2) * (1 - ratio) - (cca + 3)) * (1 - ratio) * (1 - ratio) + 1;
	float coeffects_3 = ((cca * ((1 - ratio) + 1) - 5 * cca) * ((1 - ratio) + 1) + 8 * cca) * ((1 - ratio) + 1) - 4 * cca;

	/// Sources:
	//
	// - https://chao-ji.github.io/jekyll/update/2018/07/19/BilinearResize.html
	void bilinear_interpolation(float *data, uint32_t input_width,
	uint32_t input_height, uint32_t output_width,
	uint32_t output_height, float *output) {
	float x_ratio, y_ratio;

	if (output_width > 1) {
	x_ratio = ((float)input_width - 1.0) / ((float)output_width - 1.0);

	module Issue4 exposing (suite)

	import Bytes exposing (Bytes)
	import Bytes.Encode as Encode
	import Expect
	import Image
	import Test exposing (test)


	suite =

	MODULE main
	VAR
	truck : 0..320;
	location : { a, b, s,c };
	nextLocation : { a, b, s,c};
	stockAtA : -1..120;
	stockAtB : -1..120;
	stockAtC : -1..200;

	DEFINE