/
wasm32_unknown_unknown.rs
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/
wasm32_unknown_unknown.rs
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//! A "bare wasm" target representing a WebAssembly output that makes zero
//! assumptions about its environment.
//!
//! The `wasm32-unknown-unknown` target is intended to encapsulate use cases
//! that do not rely on any imported functionality. The binaries generated are
//! entirely self-contained by default when using the standard library. Although
//! the standard library is available, most of it returns an error immediately
//! (e.g. trying to create a TCP stream or something like that).
//!
//! This target is more or less managed by the Rust and WebAssembly Working
//! Group nowadays at <https://github.com/rustwasm>.
use super::wasm32_base;
use super::{LinkerFlavor, LldFlavor, Target};
pub fn target() -> Target {
let mut options = wasm32_base::options();
options.os = "unknown".to_string();
options.linker_flavor = LinkerFlavor::Lld(LldFlavor::Wasm);
let clang_args = options.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
// Make sure clang uses LLD as its linker and is configured appropriately
// otherwise
clang_args.push("--target=wasm32-unknown-unknown".to_string());
// For now this target just never has an entry symbol no matter the output
// type, so unconditionally pass this.
clang_args.push("-Wl,--no-entry".to_string());
// Rust really needs a way for users to specify exports and imports in
// the source code. --export-dynamic isn't the right tool for this job,
// however it does have the side effect of automatically exporting a lot
// of symbols, which approximates what people want when compiling for
// wasm32-unknown-unknown expect, so use it for now.
clang_args.push("-Wl,--export-dynamic".to_string());
// Add the flags to wasm-ld's args too.
let lld_args = options.pre_link_args.entry(LinkerFlavor::Lld(LldFlavor::Wasm)).or_default();
lld_args.push("--no-entry".to_string());
lld_args.push("--export-dynamic".to_string());
Target {
llvm_target: "wasm32-unknown-unknown".to_string(),
pointer_width: 32,
data_layout: "e-m:e-p:32:32-i64:64-n32:64-S128".to_string(),
arch: "wasm32".to_string(),
options,
}
}