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

5 files changed, 34 insertions, 0 deletions

diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index ed311e273b1..112a6ea9398 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -1108,6 +1108,13 @@ impl Step for Assemble {
             let src_exe = exe("lld", target_compiler.host);
             let dst_exe = exe("rust-lld", target_compiler.host);
             builder.copy(&lld_install.join("bin").join(&src_exe), &libdir_bin.join(&dst_exe));
+            // for `-Z gcc-ld=lld`
+            let gcc_ld_dir = libdir_bin.join("gcc-ld");
+            t!(fs::create_dir(&gcc_ld_dir));
+            builder.copy(
+                &lld_install.join("bin").join(&src_exe),
+                &gcc_ld_dir.join(exe("ld", target_compiler.host)),
+            );
         }
 
         // Similarly, copy `llvm-dwp` into libdir for Split DWARF. Only copy it when the LLVM
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index aee3c8324bc..71ed0af4a7c 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -402,6 +402,10 @@ impl Step for Rustc {
             if builder.config.lld_enabled {
                 let exe = exe("rust-lld", compiler.host);
                 builder.copy(&src_dir.join(&exe), &dst_dir.join(&exe));
+                // for `-Z gcc-ld=lld`
+                let gcc_lld_dir = dst_dir.join("gcc-ld");
+                t!(fs::create_dir(&gcc_lld_dir));
+                builder.copy(&src_dir.join(&exe), &gcc_lld_dir.join(&exe));
             }
 
             // Copy over llvm-dwp if it's there
diff --git a/src/test/run-make/issue-71519/Makefile b/src/test/run-make/issue-71519/Makefile
new file mode 100644
index 00000000000..636665ec1d0
--- /dev/null
+++ b/src/test/run-make/issue-71519/Makefile
@@ -0,0 +1,6 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# needs-rust-lld
+all:
+	RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Z gcc-ld=lld -C link-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt
+	$(CGREP) -e "^LLD [0-9]+\.[0-9]+\.[0-9]+" < $(TMPDIR)/output.txt
diff --git a/src/test/run-make/issue-71519/main.rs b/src/test/run-make/issue-71519/main.rs
new file mode 100644
index 00000000000..f8d09e89753
--- /dev/null
+++ b/src/test/run-make/issue-71519/main.rs
@@ -0,0 +1,4 @@
+// test linking using cc with rust-lld injected into search path as ld
+// see rust-lang/rust#71519 for more info
+
+fn main() {}
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 983934d129a..3b620ab65ab 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -50,6 +50,15 @@ impl EarlyProps {
         let has_msan = util::MSAN_SUPPORTED_TARGETS.contains(&&*config.target);
         let has_tsan = util::TSAN_SUPPORTED_TARGETS.contains(&&*config.target);
         let has_hwasan = util::HWASAN_SUPPORTED_TARGETS.contains(&&*config.target);
+        // for `-Z gcc-ld=lld`
+        let has_rust_lld = config
+            .compile_lib_path
+            .join("rustlib")
+            .join(&config.target)
+            .join("bin")
+            .join("gcc-ld")
+            .join(if config.host.contains("windows") { "ld.exe" } else { "ld" })
+            .exists();
 
         iter_header(testfile, None, rdr, &mut |ln| {
             // we should check if any only-<platform> exists and if it exists
@@ -136,6 +145,10 @@ impl EarlyProps {
                 if config.debugger == Some(Debugger::Lldb) && ignore_lldb(config, ln) {
                     props.ignore = true;
                 }
+
+                if !has_rust_lld && config.parse_name_directive(ln, "needs-rust-lld") {
+                    props.ignore = true;
+                }
             }
 
             if let Some(s) = config.parse_aux_build(ln) {