Link against lld for linking compiled object files

bjorn3 · Sep 26, 2024 · 3fce704 · 3fce704
1 parent 5b48d87
commit 3fce704
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Showing 5 changed files with 43 additions and 2 deletions.
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -801,6 +801,29 @@ fn link_natively(
 
     // Invoke the system linker
     info!("{cmd:?}");
+
+    #[cfg(target_os = "wasi")]
+    if matches!(flavor, LinkerFlavor::Gnu(Cc::No, Lld::Yes) | LinkerFlavor::WasmLld(Cc::No)) {
+        extern "C" {
+            fn RustRunLld(
+                argc: std::ffi::c_int,
+                argv: *const *const std::ffi::c_char,
+            ) -> std::ffi::c_int;
+        }
+
+        let cmd = cmd.command();
+        println!("Linking using {cmd:?}");
+        let mut args = cmd
+            .get_args()
+            .map(|arg| std::ffi::CString::new(arg.as_encoded_bytes()).unwrap())
+            .collect::<Vec<_>>();
+        args.insert(0, std::ffi::CString::new(cmd.get_program().as_encoded_bytes()).unwrap());
+        let argv = args.iter().map(|arg| arg.as_ptr()).collect::<Vec<_>>();
+
+        let ret = unsafe { RustRunLld(args.len() as std::ffi::c_int, argv.as_ptr()) };
+        std::process::exit(ret);
+    }
+
     let retry_on_segfault = env::var("RUSTC_RETRY_LINKER_ON_SEGFAULT").is_ok();
     let unknown_arg_regex =
         Regex::new(r"(unknown|unrecognized) (command line )?(option|argument)").unwrap();

diff --git a/compiler/rustc_llvm/build.rs b/compiler/rustc_llvm/build.rs
@@ -221,6 +221,7 @@ fn main() {
         .file("llvm-wrapper/CoverageMappingWrapper.cpp")
         .file("llvm-wrapper/SymbolWrapper.cpp")
         .file("llvm-wrapper/Linker.cpp")
+        .file("llvm-wrapper/LLD.cpp")
         .cpp(true)
         .cpp_link_stdlib(None) // we handle this below
         .compile("llvm-wrapper");
@@ -328,6 +329,11 @@ fn main() {
         println!("cargo:rustc-link-lib={kind}={name}");
     }
 
+    println!("cargo:rustc-link-lib=static=LLVMOption");
+    println!("cargo:rustc-link-lib=static=lldCommon");
+    println!("cargo:rustc-link-lib=static=lldELF");
+    println!("cargo:rustc-link-lib=static=lldWasm");
+
     // LLVM ldflags
     //
     // If we're a cross-compile of LLVM then unfortunately we can't trust these

diff --git a/compiler/rustc_llvm/llvm-wrapper/LLD.cpp b/compiler/rustc_llvm/llvm-wrapper/LLD.cpp
@@ -0,0 +1,11 @@
+#include "lld/Common/Driver.h"
+
+LLD_HAS_DRIVER(elf)
+LLD_HAS_DRIVER(wasm)
+
+extern "C" int RustRunLld(int argc, char **argv) {
+    llvm::ArrayRef<const char *> args(argv, argv + argc);
+    auto r = lld::lldMain(args, llvm::outs(), llvm::errs(),
+                         {{lld::Gnu, &lld::elf::link}, {lld::Wasm, &lld::wasm::link}});
+    return r.retCode;
+}
diff --git a/config.llvm.toml b/config.llvm.toml
@@ -24,7 +24,7 @@ docs = false
 extended = false
 tools = []
 host = ["wasm32-wasip1-threads"]
-target = ["x86_64-unknown-linux-gnu", "wasm32-wasip1-threads"]
+target = ["x86_64-unknown-linux-gnu", "wasm32-wasip1"]
 cargo-native-static = true
 
 [install]

diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -515,6 +515,8 @@ impl Step for Llvm {
             return res;
         }
 
+        cfg.define("LLVM_ENABLE_PROJECTS", "lld");
+
         if target.contains("wasi") {
             let wasi_sysroot = env::var("WASI_SYSROOT").expect("WASI_SYSROOT not set");
             let wasi_sdk_path = std::path::Path::new(&wasi_sysroot)
@@ -669,7 +671,6 @@ impl Step for Llvm {
                 .define("LLVM_TOOL_XCODE_TOOLCHAIN_BUILD", "OFF")
                 .define("LLVM_TOOL_YAML2OBJ_BUILD", "OFF")
                 // .define("LLVM_ENABLE_PROJECTS", "clang;lld")
-                .define("LLVM_ENABLE_PROJECTS", "")
                 // .define("CLANG_ENABLE_ARCMT", "OFF")
                 // .define("CLANG_ENABLE_STATIC_ANALYZER", "OFF")
                 // .define("CLANG_INCLUDE_TESTS", "OFF")