gcc-lld mvp

ignore test if rust-lld not found

create ld -> rust-lld symlink at build time instead of run time

for testing in ci

copy instead of symlinking

remove linux check

test for linker, suggestions from bjorn3

fix overly restrictive lld matcher

use -Zgcc-ld flag instead of -Clinker-flavor

refactor code adding lld to gcc path

revert ci changes

suggestions from petrochenkov

rename gcc_ld to gcc-ld in dirs

1 files changed, 30 insertions, 1 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index cb56e3f9e8a..6c9ec9e7b0d 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -5,7 +5,7 @@ use rustc_fs_util::fix_windows_verbatim_for_gcc;
 use rustc_hir::def_id::CrateNum;
 use rustc_middle::middle::cstore::{DllImport, LibSource};
 use rustc_middle::middle::dependency_format::Linkage;
-use rustc_session::config::{self, CFGuard, CrateType, DebugInfo, Strip};
+use rustc_session::config::{self, CFGuard, CrateType, DebugInfo, LdImpl, Strip};
 use rustc_session::config::{OutputFilenames, OutputType, PrintRequest};
 use rustc_session::output::{check_file_is_writeable, invalid_output_for_target, out_filename};
 use rustc_session::search_paths::PathKind;
@@ -1927,6 +1927,8 @@ fn add_order_independent_options(
     out_filename: &Path,
     tmpdir: &Path,
 ) {
+    add_gcc_ld_path(cmd, sess, flavor);
+
     add_apple_sdk(cmd, sess, flavor);
 
     add_link_script(cmd, sess, tmpdir, crate_type);
@@ -2528,3 +2530,30 @@ fn get_apple_sdk_root(sdk_name: &str) -> Result<String, String> {
         Err(e) => Err(format!("failed to get {} SDK path: {}", sdk_name, e)),
     }
 }
+
+fn add_gcc_ld_path(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) {
+    if let Some(ld_impl) = sess.opts.debugging_opts.gcc_ld {
+        if let LinkerFlavor::Gcc = flavor {
+            match ld_impl {
+                LdImpl::Lld => {
+                    let tools_path =
+                        sess.host_filesearch(PathKind::All).get_tools_search_paths(false);
+                    let lld_path = tools_path
+                        .into_iter()
+                        .map(|p| p.join("gcc-ld"))
+                        .find(|p| {
+                            p.join(if sess.host.is_like_windows { "ld.exe" } else { "ld" }).exists()
+                        })
+                        .unwrap_or_else(|| sess.fatal("rust-lld (as ld) not found"));
+                    cmd.cmd().arg({
+                        let mut arg = OsString::from("-B");
+                        arg.push(lld_path);
+                        arg
+                    });
+                }
+            }
+        } else {
+            sess.fatal("option `-Z gcc-ld` is used even though linker flavor is not gcc");
+        }
+    }
+}