Rollup merge of #126967 - alexcrichton:wasm32-wasip2-tier-2, r=Mark-Simulacrum

Promote the `wasm32-wasip2` target to Tier 2

This commit promotes the `wasm32-wasip2` Rust target to tier 2 as proposed in rust-lang/compiler-team#760. There are two major changes in this PR:

1. The `dist-various-2` container, which already produces the other WASI targets, now has an extra target added for `wasm32-wasip2`.
2. A new `wasm-component-ld` binary is added to all host toolchains when LLD is enabled. This is the linker used for the `wasm32-wasip2` target.

This new linker is added for all host toolchains to ensure that all host toolchains can produce the `wasm32-wasip2` target. This is similar to how `rust-lld` was originally included for all host toolchains to be able to produce WebAssembly output when the targets were first added. The new linker is developed [here][wasm-component-ld] and is pulled in via a crates.io-based dependency to the tree here.

[wasm-component-ld]: https://github.com/bytecodealliance/wasm-component-ld

2 files changed, 16 insertions, 0 deletions

diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
index ba2ad53a94e..d4dd3e546ec 100644
--- a/src/bootstrap/src/core/build_steps/compile.rs
+++ b/src/bootstrap/src/core/build_steps/compile.rs
@@ -1820,6 +1820,21 @@ impl Step for Assemble {
                     &self_contained_lld_dir.join(exe(name, target_compiler.host)),
                 );
             }
+
+            // In addition to `rust-lld` also install `wasm-component-ld` when
+            // LLD is enabled. This is a relatively small binary that primarily
+            // delegates to the `rust-lld` binary for linking and then runs
+            // logic to create the final binary. This is used by the
+            // `wasm32-wasip2` target of Rust.
+            let wasm_component_ld_exe =
+                builder.ensure(crate::core::build_steps::tool::WasmComponentLd {
+                    compiler: build_compiler,
+                    target: target_compiler.host,
+                });
+            builder.copy_link(
+                &wasm_component_ld_exe,
+                &libdir_bin.join(wasm_component_ld_exe.file_name().unwrap()),
+            );
         }
 
         if builder.config.llvm_enabled(target_compiler.host) {
diff --git a/src/bootstrap/src/core/build_steps/tool.rs b/src/bootstrap/src/core/build_steps/tool.rs
index ad92a01bce7..7bc410b9e88 100644
--- a/src/bootstrap/src/core/build_steps/tool.rs
+++ b/src/bootstrap/src/core/build_steps/tool.rs
@@ -337,6 +337,7 @@ bootstrap_tool!(
     RustdocGUITest, "src/tools/rustdoc-gui-test", "rustdoc-gui-test", is_unstable_tool = true, allow_features = "test";
     CoverageDump, "src/tools/coverage-dump", "coverage-dump";
     RustcPerfWrapper, "src/tools/rustc-perf-wrapper", "rustc-perf-wrapper";
+    WasmComponentLd, "src/tools/wasm-component-ld", "wasm-component-ld", is_unstable_tool = true, allow_features = "min_specialization";
 );
 
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]