Create a typed wrapper for codegen backends

To avoid representing them just with strings.

Author: Kobzol

src/bootstrap/src/core/build_steps/check.rs

@@ -13,7 +13,7 @@ use crate::core::builder::{
 };
 use crate::core::config::TargetSelection;
 use crate::utils::build_stamp::{self, BuildStamp};
-use crate::{Compiler, Mode, Subcommand};
+use crate::{CodegenBackendKind, Compiler, Mode, Subcommand};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Std {
@@ -312,7 +312,7 @@ fn prepare_compiler_for_check(
 pub struct CodegenBackend {
     pub build_compiler: Compiler,
     pub target: TargetSelection,
-    pub backend: &'static str,
+    pub backend: CodegenBackendKind,
 }
 
 impl Step for CodegenBackend {
@@ -327,14 +327,14 @@ impl Step for CodegenBackend {
     fn make_run(run: RunConfig<'_>) {
         // FIXME: only check the backend(s) that were actually selected in run.paths
         let build_compiler = prepare_compiler_for_check(run.builder, run.target, Mode::Codegen);
-        for &backend in &["cranelift", "gcc"] {
+        for backend in [CodegenBackendKind::Cranelift, CodegenBackendKind::Gcc] {
             run.builder.ensure(CodegenBackend { build_compiler, target: run.target, backend });
         }
     }
 
     fn run(self, builder: &Builder<'_>) {
         // FIXME: remove once https://github.com/rust-lang/rust/issues/112393 is resolved
-        if builder.build.config.vendor && self.backend == "gcc" {
+        if builder.build.config.vendor && self.backend.is_gcc() {
             println!("Skipping checking of `rustc_codegen_gcc` with vendoring enabled.");
             return;
         }
@@ -354,19 +354,22 @@ impl Step for CodegenBackend {
 
         cargo
             .arg("--manifest-path")
-            .arg(builder.src.join(format!("compiler/rustc_codegen_{backend}/Cargo.toml")));
+            .arg(builder.src.join(format!("compiler/rustc_codegen_{}/Cargo.toml", backend.name())));
         rustc_cargo_env(builder, &mut cargo, target);
 
-        let _guard = builder.msg_check(format!("rustc_codegen_{backend}"), target, None);
+        let _guard = builder.msg_check(format!("rustc_codegen_{}", backend.name()), target, None);
 
-        let stamp = build_stamp::codegen_backend_stamp(builder, build_compiler, target, backend)
+        let stamp = build_stamp::codegen_backend_stamp(builder, build_compiler, target, &backend)
             .with_prefix("check");
 
         run_cargo(builder, cargo, builder.config.free_args.clone(), &stamp, vec![], true, false);
     }
 
     fn metadata(&self) -> Option<StepMetadata> {
-        Some(StepMetadata::check(self.backend, self.target).built_by(self.build_compiler))
+        Some(
+            StepMetadata::check(&format!("cg_{}", self.backend.name()), self.target)
+                .built_by(self.build_compiler),
+        )
     }
 }
 

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

@@ -33,7 +33,10 @@ use crate::utils::exec::command;
 use crate::utils::helpers::{
     exe, get_clang_cl_resource_dir, is_debug_info, is_dylib, symlink_dir, t, up_to_date,
 };
-use crate::{CLang, Compiler, DependencyType, FileType, GitRepo, LLVM_TOOLS, Mode, debug, trace};
+use crate::{
+    CLang, CodegenBackendKind, Compiler, DependencyType, FileType, GitRepo, LLVM_TOOLS, Mode,
+    debug, trace,
+};
 
 /// Build a standard library for the given `target` using the given `compiler`.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -1330,7 +1333,7 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetS
     }
 
     if let Some(backend) = builder.config.default_codegen_backend(target) {
-        cargo.env("CFG_DEFAULT_CODEGEN_BACKEND", backend);
+        cargo.env("CFG_DEFAULT_CODEGEN_BACKEND", backend.name());
     }
 
     let libdir_relative = builder.config.libdir_relative().unwrap_or_else(|| Path::new("lib"));
@@ -1543,7 +1546,7 @@ impl Step for RustcLink {
 pub struct CodegenBackend {
     pub target: TargetSelection,
     pub compiler: Compiler,
-    pub backend: String,
+    pub backend: CodegenBackendKind,
 }
 
 fn needs_codegen_config(run: &RunConfig<'_>) -> bool {
@@ -1568,7 +1571,7 @@ fn is_codegen_cfg_needed(path: &TaskPath, run: &RunConfig<'_>) -> bool {
     if path.contains(CODEGEN_BACKEND_PREFIX) {
         let mut needs_codegen_backend_config = true;
         for backend in run.builder.config.codegen_backends(run.target) {
-            if path.ends_with(&(CODEGEN_BACKEND_PREFIX.to_owned() + backend)) {
+            if path.ends_with(&(CODEGEN_BACKEND_PREFIX.to_owned() + backend.name())) {
                 needs_codegen_backend_config = false;
             }
         }
@@ -1602,7 +1605,7 @@ impl Step for CodegenBackend {
         }
 
         for backend in run.builder.config.codegen_backends(run.target) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                 continue; // Already built as part of rustc
             }
 
@@ -1663,20 +1666,21 @@ impl Step for CodegenBackend {
         );
         cargo
             .arg("--manifest-path")
-            .arg(builder.src.join(format!("compiler/rustc_codegen_{backend}/Cargo.toml")));
+            .arg(builder.src.join(format!("compiler/rustc_codegen_{}/Cargo.toml", backend.name())));
         rustc_cargo_env(builder, &mut cargo, target);
 
         // Ideally, we'd have a separate step for the individual codegen backends,
         // like we have in tests (test::CodegenGCC) but that would require a lot of restructuring.
         // If the logic gets more complicated, it should probably be done.
-        if backend == "gcc" {
+        if backend.is_gcc() {
             let gcc = builder.ensure(Gcc { target });
             add_cg_gcc_cargo_flags(&mut cargo, &gcc);
         }
 
         let tmp_stamp = BuildStamp::new(&out_dir).with_prefix("tmp");
 
-        let _guard = builder.msg_build(compiler, format_args!("codegen backend {backend}"), target);
+        let _guard =
+            builder.msg_build(compiler, format_args!("codegen backend {}", backend.name()), target);
         let files = run_cargo(builder, cargo, vec![], &tmp_stamp, vec![], false, false);
         if builder.config.dry_run() {
             return;
@@ -1731,7 +1735,7 @@ fn copy_codegen_backends_to_sysroot(
     }
 
     for backend in builder.config.codegen_backends(target) {
-        if backend == "llvm" {
+        if backend.is_llvm() {
             continue; // Already built as part of rustc
         }
 
@@ -2161,7 +2165,7 @@ impl Step for Assemble {
         let _codegen_backend_span =
             span!(tracing::Level::DEBUG, "building requested codegen backends").entered();
         for backend in builder.config.codegen_backends(target_compiler.host) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                 debug!("llvm codegen backend is already built as part of rustc");
                 continue; // Already built as part of rustc
             }

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

@@ -32,7 +32,7 @@ use crate::utils::helpers::{
     exe, is_dylib, move_file, t, target_supports_cranelift_backend, timeit,
 };
 use crate::utils::tarball::{GeneratedTarball, OverlayKind, Tarball};
-use crate::{Compiler, DependencyType, FileType, LLVM_TOOLS, Mode, trace};
+use crate::{CodegenBackendKind, Compiler, DependencyType, FileType, LLVM_TOOLS, Mode, trace};
 
 pub fn pkgname(builder: &Builder<'_>, component: &str) -> String {
     format!("{}-{}", component, builder.rust_package_vers())
@@ -1372,10 +1372,10 @@ impl Step for Miri {
     }
 }
 
-#[derive(Debug, PartialOrd, Ord, Clone, Hash, PartialEq, Eq)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct CodegenBackend {
     pub compiler: Compiler,
-    pub backend: String,
+    pub backend: CodegenBackendKind,
 }
 
 impl Step for CodegenBackend {
@@ -1389,7 +1389,7 @@ impl Step for CodegenBackend {
 
     fn make_run(run: RunConfig<'_>) {
         for backend in run.builder.config.codegen_backends(run.target) {
-            if backend == "llvm" {
+            if backend.is_llvm() {
                 continue; // Already built as part of rustc
             }
 
@@ -1412,28 +1412,30 @@ impl Step for CodegenBackend {
             return None;
         }
 
-        if !builder.config.codegen_backends(self.compiler.host).contains(&self.backend.to_string())
-        {
+        if !builder.config.codegen_backends(self.compiler.host).contains(&self.backend) {
             return None;
         }
 
-        if self.backend == "cranelift" && !target_supports_cranelift_backend(self.compiler.host) {
+        if self.backend.is_cranelift() && !target_supports_cranelift_backend(self.compiler.host) {
             builder.info("target not supported by rustc_codegen_cranelift. skipping");
             return None;
         }
 
         let compiler = self.compiler;
         let backend = self.backend;
 
-        let mut tarball =
-            Tarball::new(builder, &format!("rustc-codegen-{backend}"), &compiler.host.triple);
-        if backend == "cranelift" {
+        let mut tarball = Tarball::new(
+            builder,
+            &format!("rustc-codegen-{}", backend.name()),
+            &compiler.host.triple,
+        );
+        if backend.is_cranelift() {
             tarball.set_overlay(OverlayKind::RustcCodegenCranelift);
         } else {
-            panic!("Unknown backend rustc_codegen_{backend}");
+            panic!("Unknown backend rustc_codegen_{}", backend.name());
         }
         tarball.is_preview(true);
-        tarball.add_legal_and_readme_to(format!("share/doc/rustc_codegen_{backend}"));
+        tarball.add_legal_and_readme_to(format!("share/doc/rustc_codegen_{}", backend.name()));
 
         let src = builder.sysroot(compiler);
         let backends_src = builder.sysroot_codegen_backends(compiler);
@@ -1445,7 +1447,7 @@ impl Step for CodegenBackend {
         // Don't use custom libdir here because ^lib/ will be resolved again with installer
         let backends_dst = PathBuf::from("lib").join(backends_rel);
 
-        let backend_name = format!("rustc_codegen_{backend}");
+        let backend_name = format!("rustc_codegen_{}", backend.name());
         let mut found_backend = false;
         for backend in fs::read_dir(&backends_src).unwrap() {
             let file_name = backend.unwrap().file_name();
@@ -1575,7 +1577,7 @@ impl Step for Extended {
         add_component!("analysis" => Analysis { compiler, target });
         add_component!("rustc-codegen-cranelift" => CodegenBackend {
             compiler: builder.compiler(stage, target),
-            backend: "cranelift".to_string(),
+            backend: CodegenBackendKind::Cranelift,
         });
         add_component!("llvm-bitcode-linker" => LlvmBitcodeLinker {
             build_compiler: compiler,

src/bootstrap/src/core/build_steps/install.rs

@@ -12,7 +12,7 @@ use crate::core::config::{Config, TargetSelection};
 use crate::utils::exec::command;
 use crate::utils::helpers::t;
 use crate::utils::tarball::GeneratedTarball;
-use crate::{Compiler, Kind};
+use crate::{CodegenBackendKind, Compiler, Kind};
 
 #[cfg(target_os = "illumos")]
 const SHELL: &str = "bash";
@@ -276,7 +276,7 @@ install!((self, builder, _config),
     RustcCodegenCranelift, alias = "rustc-codegen-cranelift", Self::should_build(_config), only_hosts: true, {
         if let Some(tarball) = builder.ensure(dist::CodegenBackend {
             compiler: self.compiler,
-            backend: "cranelift".to_string(),
+            backend: CodegenBackendKind::Cranelift,
         }) {
             install_sh(builder, "rustc-codegen-cranelift", self.compiler.stage, Some(self.target), &tarball);
         } else {

src/bootstrap/src/core/build_steps/test.rs

@@ -33,7 +33,7 @@ use crate::utils::helpers::{
     linker_flags, t, target_supports_cranelift_backend, up_to_date,
 };
 use crate::utils::render_tests::{add_flags_and_try_run_tests, try_run_tests};
-use crate::{CLang, DocTests, GitRepo, Mode, PathSet, debug, envify};
+use crate::{CLang, CodegenBackendKind, DocTests, GitRepo, Mode, PathSet, debug, envify};
 
 const ADB_TEST_DIR: &str = "/data/local/tmp/work";
 
@@ -1786,7 +1786,9 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.host_target));
 
         if let Some(codegen_backend) = builder.config.default_codegen_backend(compiler.host) {
-            cmd.arg("--codegen-backend").arg(&codegen_backend);
+            // Tells compiletest which codegen backend is used by default by the compiler.
+            // It is used to e.g. ignore tests that don't support that codegen backend.
+            cmd.arg("--codegen-backend").arg(codegen_backend.name());
         }
 
         if builder.build.config.llvm_enzyme {
@@ -3406,7 +3408,7 @@ impl Step for CodegenCranelift {
             return;
         }
 
-        if !builder.config.codegen_backends(run.target).contains(&"cranelift".to_owned()) {
+        if !builder.config.codegen_backends(run.target).contains(&CodegenBackendKind::Cranelift) {
             builder.info("cranelift not in rust.codegen-backends. skipping");
             return;
         }
@@ -3533,7 +3535,7 @@ impl Step for CodegenGCC {
             return;
         }
 
-        if !builder.config.codegen_backends(run.target).contains(&"gcc".to_owned()) {
+        if !builder.config.codegen_backends(run.target).contains(&CodegenBackendKind::Gcc) {
             builder.info("gcc not in rust.codegen-backends. skipping");
             return;
         }

src/bootstrap/src/core/builder/cargo.rs

@@ -10,8 +10,9 @@ use crate::core::config::flags::Color;
 use crate::utils::build_stamp;
 use crate::utils::helpers::{self, LldThreads, check_cfg_arg, linker_args, linker_flags};
 use crate::{
-    BootstrapCommand, CLang, Compiler, Config, DocTests, DryRun, EXTRA_CHECK_CFGS, GitRepo, Mode,
-    RemapScheme, TargetSelection, command, prepare_behaviour_dump_dir, t,
+    BootstrapCommand, CLang, CodegenBackendKind, Compiler, Config, DocTests, DryRun,
+    EXTRA_CHECK_CFGS, GitRepo, Mode, RemapScheme, TargetSelection, command,
+    prepare_behaviour_dump_dir, t,
 };
 
 /// Represents flag values in `String` form with whitespace delimiter to pass it to the compiler
@@ -1286,7 +1287,8 @@ impl Builder<'_> {
 
             if let Some(limit) = limit
                 && (build_compiler_stage == 0
-                    || self.config.default_codegen_backend(target).unwrap_or_default() == "llvm")
+                    || self.config.default_codegen_backend(target).unwrap_or_default()
+                        == CodegenBackendKind::Llvm)
             {
                 rustflags.arg(&format!("-Cllvm-args=-import-instr-limit={limit}"));
             }

src/bootstrap/src/core/builder/mod.rs

@@ -141,7 +141,7 @@ pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
 #[allow(unused)]
 #[derive(Debug, PartialEq, Eq)]
 pub struct StepMetadata {
-    name: &'static str,
+    name: String,
     kind: Kind,
     target: TargetSelection,
     built_by: Option<Compiler>,
@@ -151,28 +151,28 @@ pub struct StepMetadata {
 }
 
 impl StepMetadata {
-    pub fn build(name: &'static str, target: TargetSelection) -> Self {
+    pub fn build(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Build)
     }
 
-    pub fn check(name: &'static str, target: TargetSelection) -> Self {
+    pub fn check(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Check)
     }
 
-    pub fn doc(name: &'static str, target: TargetSelection) -> Self {
+    pub fn doc(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Doc)
     }
 
-    pub fn dist(name: &'static str, target: TargetSelection) -> Self {
+    pub fn dist(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Dist)
     }
 
-    pub fn test(name: &'static str, target: TargetSelection) -> Self {
+    pub fn test(name: &str, target: TargetSelection) -> Self {
         Self::new(name, target, Kind::Test)
     }
 
-    fn new(name: &'static str, target: TargetSelection, kind: Kind) -> Self {
-        Self { name, kind, target, built_by: None, stage: None, metadata: None }
+    fn new(name: &str, target: TargetSelection, kind: Kind) -> Self {
+        Self { name: name.to_string(), kind, target, built_by: None, stage: None, metadata: None }
     }
 
     pub fn built_by(mut self, compiler: Compiler) -> Self {