T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Use global_asm! instead of external assembly files (#4306)

Browse Source 
* Use `global_asm!` instead of external assembly files

This commit moves the external assembly files of the `wasmtime-fiber`
crate into `global_asm!` blocks defined in Rust. The motivation for
doing this is not very strong at this time, but the points in favor of
this are:

* One less tool needed to cross-compile Wasmtime. A linker is still
  needed but perhaps one day that will improve as well.
* A "modern" assembler, built-in to LLVM, is used instead of whatever
  appears on the system.

The first point hasn't really cropped up that much and typically getting
an assembler is just as hard as getting a linker nowadays. The second
point though has us using `hint #xx` in aarch64 assembly instead of the
actual instructions for assembler compatibility, and I believe that's no
longer necessary because the LLVM assembler supports the modern
instruction names.

The translation of the x86/x86_64 assembly has been done to Intel
syntax as well as opposed to the old AT&T syntax since that's Rust's
default. Additionally s390x still remains in an external assembler file
because `global_asm!` is still unstable in Rust on that platform.

* Simplify alignment specification

* Temporarily disable fail-fast

* Add `.cfi_def_cfa_offset 0` to fix CI

* Turn off fail-fast

* Review comments
This commit is contained in:
Alex Crichton
2022-06-27 13:20:19 -05:00
committed by GitHub
parent 0ef873f1bd
commit 4543a07bb5
16 changed files with 631 additions and 603 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
crates/fiber/build.rs
View File

@@ -1,23 +1,18 @@
use std::env;
use std::fs;
fn main() {
let mut build = cc::Build::new();
let arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap();
let family = env::var("CARGO_CFG_TARGET_FAMILY").unwrap();
let os = env::var("CARGO_CFG_TARGET_OS").unwrap();
let family_file = format!("src/arch/{}.c", family);
let arch_file = format!("src/arch/{}.S", arch);
if fs::metadata(&family_file).is_ok() {
build.file(&family_file);
} else if fs::metadata(&arch_file).is_ok() {
build.file(&arch_file);
if os == "windows" {
build.file("src/windows.c");
} else if arch == "s390x" {
build.file("src/unix/s390x.S");
} else {
panic!(
"wasmtime doesn't support fibers on platform: {}",
env::var("TARGET").unwrap()
);
// assume that this is included via inline assembly in the crate itself,
// and the crate will otherwise have a `compile_error!` for unsupported
// platforms.
return;
}
build.define(&format!("CFG_TARGET_OS_{}", os), None);
build.define(&format!("CFG_TARGET_ARCH_{}", arch), None);