compiler/rustc_target/src/spec/wasm64_unknown_unknown.rs

   1 //! A "bare wasm" target representing a WebAssembly output that makes zero
   2 //! assumptions about its environment.
   3 //!
   4 //! The `wasm64-unknown-unknown` target is intended to encapsulate use cases
   5 //! that do not rely on any imported functionality. The binaries generated are
   6 //! entirely self-contained by default when using the standard library. Although
   7 //! the standard library is available, most of it returns an error immediately
   8 //! (e.g. trying to create a TCP stream or something like that).
   9
  10 use super::wasm_base;
  11 use super::{LinkerFlavor, LldFlavor, Target};
  12
  13 pub fn target() -> Target {
  14     let mut options = wasm_base::options();
  15     options.os = "unknown".to_string();
  16     options.linker_flavor = LinkerFlavor::Lld(LldFlavor::Wasm);
  17     let clang_args = options.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
  18
  19     // Make sure clang uses LLD as its linker and is configured appropriately
  20     // otherwise
  21     clang_args.push("--target=wasm64-unknown-unknown".to_string());
  22
  23     // For now this target just never has an entry symbol no matter the output
  24     // type, so unconditionally pass this.
  25     clang_args.push("-Wl,--no-entry".to_string());
  26     options
  27         .pre_link_args
  28         .get_mut(&LinkerFlavor::Lld(LldFlavor::Wasm))
  29         .unwrap()
  30         .push("--no-entry".to_string());
  31
  32     Target {
  33         llvm_target: "wasm64-unknown-unknown".to_string(),
  34         pointer_width: 64,
  35         data_layout: "e-m:e-p:64:64-i64:64-n32:64-S128".to_string(),
  36         arch: "wasm64".to_string(),
  37         options,
  38     }
  39 }