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532ac7d7 XL |
1 | //! A "bare wasm" target representing a WebAssembly output that makes zero |
2 | //! assumptions about its environment. | |
3 | //! | |
4 | //! The `wasm32-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 | //! This target is more or less managed by the Rust and WebAssembly Working | |
29967ef6 | 11 | //! Group nowadays at <https://github.com/rustwasm>. |
532ac7d7 | 12 | |
cdc7bbd5 | 13 | use super::wasm_base; |
dfeec247 | 14 | use super::{LinkerFlavor, LldFlavor, Target}; |
cdc7bbd5 | 15 | use crate::spec::abi::Abi; |
abe05a73 | 16 | |
29967ef6 | 17 | pub fn target() -> Target { |
cdc7bbd5 | 18 | let mut options = wasm_base::options(); |
ee023bcb | 19 | options.os = "unknown".into(); |
29967ef6 | 20 | options.linker_flavor = LinkerFlavor::Lld(LldFlavor::Wasm); |
cdc7bbd5 XL |
21 | |
22 | // This is a default for backwards-compatibility with the original | |
23 | // definition of this target oh-so-long-ago. Once the "wasm" ABI is | |
24 | // stable and the wasm-bindgen project has switched to using it then there's | |
25 | // no need for this and it can be removed. | |
26 | // | |
27 | // Currently this is the reason that this target's ABI is mismatched with | |
28 | // clang's ABI. This means that, in the limit, you can't merge C and Rust | |
29 | // code on this target due to this ABI mismatch. | |
30 | options.default_adjusted_cabi = Some(Abi::Wasm); | |
31 | ||
32 | let clang_args = options.pre_link_args.entry(LinkerFlavor::Gcc).or_default(); | |
abe05a73 | 33 | |
532ac7d7 XL |
34 | // Make sure clang uses LLD as its linker and is configured appropriately |
35 | // otherwise | |
ee023bcb | 36 | clang_args.push("--target=wasm32-unknown-unknown".into()); |
2c00a5a8 | 37 | |
532ac7d7 XL |
38 | // For now this target just never has an entry symbol no matter the output |
39 | // type, so unconditionally pass this. | |
ee023bcb | 40 | clang_args.push("-Wl,--no-entry".into()); |
5869c6ff XL |
41 | |
42 | // Rust really needs a way for users to specify exports and imports in | |
43 | // the source code. --export-dynamic isn't the right tool for this job, | |
44 | // however it does have the side effect of automatically exporting a lot | |
45 | // of symbols, which approximates what people want when compiling for | |
46 | // wasm32-unknown-unknown expect, so use it for now. | |
ee023bcb | 47 | clang_args.push("-Wl,--export-dynamic".into()); |
5869c6ff XL |
48 | |
49 | // Add the flags to wasm-ld's args too. | |
cdc7bbd5 | 50 | let lld_args = options.pre_link_args.entry(LinkerFlavor::Lld(LldFlavor::Wasm)).or_default(); |
ee023bcb FG |
51 | lld_args.push("--no-entry".into()); |
52 | lld_args.push("--export-dynamic".into()); | |
0bf4aa26 | 53 | |
29967ef6 | 54 | Target { |
ee023bcb | 55 | llvm_target: "wasm32-unknown-unknown".into(), |
29967ef6 | 56 | pointer_width: 32, |
ee023bcb FG |
57 | data_layout: "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20".into(), |
58 | arch: "wasm32".into(), | |
532ac7d7 | 59 | options, |
29967ef6 | 60 | } |
abe05a73 | 61 | } |