Wild experiments

Cargo.toml

@@ -45,6 +45,7 @@ members = [
   "src/tools/unicode-table-generator",
   "src/tools/unstable-book-gen",
   "src/tools/wasm-component-ld",
+  # "src/tools/wild-linker",
   "src/tools/x",
 # tidy-alphabetical-end
 ]
@@ -53,6 +54,7 @@ exclude = [
   "build",
   "compiler/rustc_codegen_cranelift",
   "compiler/rustc_codegen_gcc",
+  "src/tools/wild-linker",
   "src/bootstrap",
   "tests/rustdoc-gui",
   # HACK(eddyb) This hardcodes the fact that our CI uses `/checkout/obj`.
@@ -92,4 +94,3 @@ codegen-units = 1
 # If you want to use a crate with local modifications, you can set a path or git dependency here.
 # For git dependencies, also add your source to ALLOWED_SOURCES in src/tools/tidy/src/extdeps.rs.
 #[patch.crates-io]
-

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1326,7 +1326,8 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
                     LinkerFlavor::Gnu(Cc::Yes, _)
                     | LinkerFlavor::Darwin(Cc::Yes, _)
                     | LinkerFlavor::WasmLld(Cc::Yes)
-                    | LinkerFlavor::Unix(Cc::Yes) => {
+                    | LinkerFlavor::Unix(Cc::Yes)
+                    | LinkerFlavor::Wild => {
                         if cfg!(any(target_os = "solaris", target_os = "illumos")) {
                             // On historical Solaris systems, "cc" may have
                             // been Sun Studio, which is not flag-compatible
@@ -1366,6 +1367,8 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
                 });
                 let flavor = sess.target.linker_flavor.with_linker_hints(stem);
                 let flavor = adjust_flavor_to_features(flavor, features);
+                let linker =
+                    if flavor == LinkerFlavor::Wild { PathBuf::from("cc") } else { linker };
                 Some((linker, flavor))
             }
             (None, None) => None,
@@ -2482,6 +2485,8 @@ fn add_order_independent_options(
     // Take care of the flavors and CLI options requesting the `lld` linker.
     add_lld_args(cmd, sess, flavor, self_contained_components);
 
+    add_wild_args(cmd, sess, flavor, self_contained_components);
+
     add_apple_link_args(cmd, sess, flavor);
 
     let apple_sdk_root = add_apple_sdk(cmd, sess, flavor);
@@ -3403,6 +3408,59 @@ fn add_lld_args(
     }
 }
 
+fn add_wild_args(
+    cmd: &mut dyn Linker,
+    sess: &Session,
+    flavor: LinkerFlavor,
+    self_contained_components: LinkSelfContainedComponents,
+) {
+    // Either Wild or LLD to make it work with CI
+    if flavor != LinkerFlavor::Wild || std::env::var_os("BUILDING_RUSTC").is_some() {
+        let self_contained_cli = sess.opts.cg.link_self_contained.is_linker_enabled();
+        let self_contained_target = self_contained_components.is_linker_enabled();
+
+        let self_contained_linker = self_contained_cli || self_contained_target;
+        if self_contained_linker && !sess.opts.cg.link_self_contained.is_linker_disabled() {
+            let mut linker_path_exists = false;
+            for path in sess.get_tools_search_paths(false) {
+                let linker_path = path.join("gcc-ld");
+                linker_path_exists |= linker_path.exists();
+                cmd.cc_arg({
+                    let mut arg = OsString::from("-B");
+                    arg.push(linker_path);
+                    arg
+                });
+            }
+            if !linker_path_exists {
+                sess.dcx().emit_fatal(errors::SelfContainedLinkerMissing);
+            }
+        }
+
+        if !sess.target.is_like_wasm {
+            cmd.cc_arg("-fuse-ld=lld");
+        }
+        return ();
+    }
+
+    let mut linker_path_exists = false;
+    for path in sess.get_tools_search_paths(false) {
+        let linker_path = path.join("wild-gcc-ld");
+        linker_path_exists |= linker_path.exists();
+        cmd.cc_arg({
+            let mut arg = OsString::from("-B");
+            arg.push(linker_path);
+            arg
+        });
+        cmd.cc_arg("-Wl,--threads=8");
+        // cmd.cc_arg("-Wl,--no-fork");
+    }
+    if !linker_path_exists {
+        // As a sanity check, we emit an error if none of these paths exist: we want
+        // self-contained linking and have no linker.
+        sess.dcx().emit_fatal(errors::SelfContainedLinkerMissing);
+    }
+}
+
 // gold has been deprecated with binutils 2.44
 // and is known to behave incorrectly around Rust programs.
 // There have been reports of being unable to bootstrap with gold:

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -161,6 +161,15 @@ pub(crate) fn get_linker<'a>(
         LinkerFlavor::Bpf => Box::new(BpfLinker { cmd, sess }) as Box<dyn Linker>,
         LinkerFlavor::Llbc => Box::new(LlbcLinker { cmd, sess }) as Box<dyn Linker>,
         LinkerFlavor::Ptx => Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>,
+        LinkerFlavor::Wild => Box::new(GccLinker {
+            cmd,
+            sess,
+            target_cpu,
+            hinted_static: None,
+            is_ld: false,
+            is_gnu: true,
+            uses_lld: flavor.uses_lld(),
+        }),
     }
 }
 

compiler/rustc_session/src/options.rs

@@ -862,7 +862,7 @@ mod desc {
     pub(crate) const parse_link_self_contained: &str = "one of: `y`, `yes`, `on`, `n`, `no`, `off`, or a list of enabled (`+` prefix) and disabled (`-` prefix) \
         components: `crto`, `libc`, `unwind`, `linker`, `sanitizers`, `mingw`";
     pub(crate) const parse_linker_features: &str =
-        "a list of enabled (`+` prefix) and disabled (`-` prefix) features: `lld`";
+        "a list of enabled (`+` prefix) and disabled (`-` prefix) features: `lld`, `wild`";
     pub(crate) const parse_polonius: &str = "either no value or `legacy` (the default), or `next`";
     pub(crate) const parse_stack_protector: &str =
         "one of (`none` (default), `basic`, `strong`, or `all`)";

compiler/rustc_target/src/spec/mod.rs

@@ -127,6 +127,8 @@
     /// Emscripten Compiler Frontend, a wrapper around `WasmLld(Cc::Yes)` that has a different
     /// interface and produces some additional JavaScript output.
     EmCc,
+    // TODO: This needs some design on how to proceed
+    Wild,
     // Below: other linker-like tools with unique interfaces for exotic targets.
     /// Linker tool for BPF.
     Bpf,
@@ -153,6 +155,7 @@
     Bpf,
     Ptx,
     Llbc,
+    Wild,
 
     // Legacy stable values
     Gcc,
@@ -178,7 +181,8 @@
             | LinkerFlavorCli::Ld
             | LinkerFlavorCli::Lld(..)
             | LinkerFlavorCli::Msvc(Lld::No)
-            | LinkerFlavorCli::Em => false,
+            | LinkerFlavorCli::Em
+            | LinkerFlavorCli::Wild => false,
         }
     }
 }
@@ -245,6 +249,7 @@
             LinkerFlavorCli::Bpf => LinkerFlavor::Bpf,
             LinkerFlavorCli::Llbc => LinkerFlavor::Llbc,
             LinkerFlavorCli::Ptx => LinkerFlavor::Ptx,
+            LinkerFlavorCli::Wild => LinkerFlavor::Wild,
 
             // Below: legacy stable values
             LinkerFlavorCli::Gcc => match lld_flavor {
@@ -285,6 +290,7 @@
             LinkerFlavor::Bpf => LinkerFlavorCli::Bpf,
             LinkerFlavor::Llbc => LinkerFlavorCli::Llbc,
             LinkerFlavor::Ptx => LinkerFlavorCli::Ptx,
+            LinkerFlavor::Wild => LinkerFlavorCli::Wild,
         }
     }
 
@@ -300,6 +306,7 @@
             LinkerFlavor::Bpf => LinkerFlavorCli::Bpf,
             LinkerFlavor::Llbc => LinkerFlavorCli::Llbc,
             LinkerFlavor::Ptx => LinkerFlavorCli::Ptx,
+            LinkerFlavor::Wild => LinkerFlavorCli::Wild,
         }
     }
 
@@ -314,6 +321,7 @@
             LinkerFlavorCli::EmCc => (Some(Cc::Yes), Some(Lld::Yes)),
             LinkerFlavorCli::Bpf | LinkerFlavorCli::Ptx => (None, None),
             LinkerFlavorCli::Llbc => (None, None),
+            LinkerFlavorCli::Wild => (None, None),
 
             // Below: legacy stable values
             LinkerFlavorCli::Gcc => (Some(Cc::Yes), None),
@@ -332,6 +340,8 @@
 
         if stem == "llvm-bitcode-linker" {
             Ok(Self::Llbc)
+        } else if stem == "wild" {
+            Ok(Self::Wild)
         } else if stem == "emcc" // GCC/Clang can have an optional target prefix.
             || stem == "gcc"
             || stem.ends_with("-gcc")
@@ -369,7 +379,11 @@
             LinkerFlavor::WasmLld(cc) => LinkerFlavor::WasmLld(cc_hint.unwrap_or(cc)),
             LinkerFlavor::Unix(cc) => LinkerFlavor::Unix(cc_hint.unwrap_or(cc)),
             LinkerFlavor::Msvc(lld) => LinkerFlavor::Msvc(lld_hint.unwrap_or(lld)),
-            LinkerFlavor::EmCc | LinkerFlavor::Bpf | LinkerFlavor::Llbc | LinkerFlavor::Ptx => self,
+            LinkerFlavor::EmCc
+            | LinkerFlavor::Bpf
+            | LinkerFlavor::Llbc
+            | LinkerFlavor::Ptx
+            | LinkerFlavor::Wild => self,
         }
     }
 
@@ -397,7 +411,8 @@
                 | (LinkerFlavor::EmCc, LinkerFlavorCli::EmCc)
                 | (LinkerFlavor::Bpf, LinkerFlavorCli::Bpf)
                 | (LinkerFlavor::Llbc, LinkerFlavorCli::Llbc)
-                | (LinkerFlavor::Ptx, LinkerFlavorCli::Ptx) => return true,
+                | (LinkerFlavor::Ptx, LinkerFlavorCli::Ptx)
+                | (LinkerFlavor::Wild, LinkerFlavorCli::Wild) => return true,
                 // 2. The linker flavor is independent of target and compatible
                 (LinkerFlavor::Ptx, LinkerFlavorCli::Llbc) => return true,
                 _ => {}
@@ -427,6 +442,7 @@
             LinkerFlavor::Darwin(..) => LldFlavor::Ld64,
             LinkerFlavor::WasmLld(..) => LldFlavor::Wasm,
             LinkerFlavor::Msvc(..) => LldFlavor::Link,
+            LinkerFlavor::Wild => todo!(),
         }
     }
 
@@ -449,7 +465,8 @@
             | LinkerFlavor::Unix(_)
             | LinkerFlavor::Bpf
             | LinkerFlavor::Llbc
-            | LinkerFlavor::Ptx => false,
+            | LinkerFlavor::Ptx
+            | LinkerFlavor::Wild => false,
         }
     }
 
@@ -461,7 +478,8 @@
             | LinkerFlavor::Darwin(Cc::Yes, _)
             | LinkerFlavor::WasmLld(Cc::Yes)
             | LinkerFlavor::Unix(Cc::Yes)
-            | LinkerFlavor::EmCc => true,
+            | LinkerFlavor::EmCc
+            | LinkerFlavor::Wild => true,
             LinkerFlavor::Gnu(..)
             | LinkerFlavor::Darwin(..)
             | LinkerFlavor::WasmLld(_)
@@ -546,6 +564,7 @@
     (LinkerFlavorCli::Bpf) "bpf"
     (LinkerFlavorCli::Llbc) "llbc"
     (LinkerFlavorCli::Ptx) "ptx"
+    (LinkerFlavorCli::Wild) "wild"
 
     // Legacy stable flavors
     (LinkerFlavorCli::Gcc) "gcc"
@@ -2847,6 +2866,7 @@
             assert_eq!(lld, Lld::No);
             insert(LinkerFlavor::Msvc(Lld::Yes));
         }
+        LinkerFlavor::Wild => insert(LinkerFlavor::Wild),
         LinkerFlavor::WasmLld(..)
         | LinkerFlavor::Unix(..)
         | LinkerFlavor::EmCc
@@ -3237,6 +3257,7 @@
                     | LinkerFlavor::Llbc => {
                         check_eq!(flavor, self.linker_flavor, "mixing different linker flavors")
                     }
+                    LinkerFlavor::Wild => todo!(),
                 }
 
                 // Check that link args for cc and non-cc versions of flavors are consistent.

compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_gnu.rs

@@ -27,6 +27,8 @@ pub(crate) fn target() -> Target {
         base.link_self_contained = crate::spec::LinkSelfContainedDefault::with_linker();
     }
 
+    base.linker_flavor = LinkerFlavor::Wild;
+
     Target {
         llvm_target: "x86_64-unknown-linux-gnu".into(),
         metadata: TargetMetadata {

src/bootstrap/src/core/build_steps/compile.rs

@@ -20,7 +20,9 @@ use serde_derive::Deserialize;
 use tracing::span;
 
 use crate::core::build_steps::gcc::{Gcc, GccOutput, add_cg_gcc_cargo_flags};
-use crate::core::build_steps::tool::{RustcPrivateCompilers, SourceType, copy_lld_artifacts};
+use crate::core::build_steps::tool::{
+    RustcPrivateCompilers, SourceType, copy_lld_artifacts, copy_wild_artifacts,
+};
 use crate::core::build_steps::{dist, llvm};
 use crate::core::builder;
 use crate::core::builder::{
@@ -2315,6 +2317,15 @@ impl Step for Assemble {
             copy_lld_artifacts(builder, lld_wrapper, target_compiler);
         }
 
+        if builder.host_target.triple == "x86_64-unknown-linux-gnu" {
+            let wild_wrapper =
+                builder.ensure(crate::core::build_steps::tool::WildLinker::for_use_by_compiler(
+                    builder,
+                    target_compiler,
+                ));
+            copy_wild_artifacts(builder, wild_wrapper, target_compiler);
+        }
+
         if builder.config.llvm_enabled(target_compiler.host) && builder.config.llvm_tools_enabled {
             debug!(
                 "llvm and llvm tools enabled; copying `llvm-objcopy` as `rust-objcopy` to \

src/bootstrap/src/core/build_steps/dist.rs

@@ -552,6 +552,33 @@ impl Step for Rustc {
                 }
             }
 
+            if builder.host_target.triple == "x86_64-unknown-linux-gnu" {
+                let src_dir = builder.sysroot_target_bindir(target_compiler, target);
+                let rust_wild = exe("rust-wild", target_compiler.host);
+                builder.copy_link(
+                    &src_dir.join(&rust_wild),
+                    &dst_dir.join(&rust_wild),
+                    FileType::Executable,
+                );
+                let self_contained_wild_src_dir = src_dir.join("wild-gcc-ld");
+                let self_contained_wild_dst_dir = dst_dir.join("wild-gcc-ld");
+                t!(fs::create_dir(&self_contained_wild_dst_dir));
+                let wild_name = "wild";
+                let exe_name = exe(wild_name, target_compiler.host);
+                builder.copy_link(
+                    &self_contained_wild_src_dir.join(&exe_name),
+                    &self_contained_wild_dst_dir.join(&exe_name),
+                    FileType::Executable,
+                );
+                // Pretend Wild is LD so the compiler can pick it up
+                let exe_name = exe("ld", target_compiler.host);
+                builder.copy_link(
+                    &self_contained_wild_src_dir.join(&exe_name),
+                    &self_contained_wild_dst_dir.join(&exe_name),
+                    FileType::Executable,
+                );
+            }
+
             if builder.config.llvm_enabled(target_compiler.host)
                 && builder.config.llvm_tools_enabled
             {