Assorted bootstrap LLVM refactors (part 2/N)

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

@@ -20,6 +20,7 @@ use serde_derive::Deserialize;
 use tracing::span;
 
 use crate::core::build_steps::gcc::{Gcc, GccOutput, GccTargetPair};
+use crate::core::build_steps::llvm::{LlvmFromCi, prebuilt_llvm_output};
 use crate::core::build_steps::tool::{RustcPrivateCompilers, SourceType, copy_lld_artifacts};
 use crate::core::build_steps::{dist, llvm};
 use crate::core::builder::{
@@ -505,14 +506,16 @@ pub fn std_crates_for_make_run(run: &RunConfig<'_>) -> Vec<String> {
 /// downloaded copy of CI LLVM, then we try to use the `compiler-rt` sources from
 /// there instead, which lets us avoid checking out the LLVM submodule.
 fn compiler_rt_for_profiler(builder: &Builder<'_>) -> PathBuf {
-    // Try to use `compiler-rt` sources from downloaded CI LLVM, if possible.
-    if builder.config.llvm_from_ci {
-        // CI LLVM might not have been downloaded yet, so try to download it now.
-        builder.config.maybe_download_ci_llvm();
-        let ci_llvm_compiler_rt = builder.config.ci_llvm_root().join("compiler-rt");
-        if ci_llvm_compiler_rt.exists() {
-            return ci_llvm_compiler_rt;
+    // Try to use `compiler-rt` sources from downloaded CI LLVM, if available
+    if let Some(downloaded_llvm) = builder.ensure(LlvmFromCi { target: builder.host_target }) {
+        let ci_llvm_compiler_rt = downloaded_llvm.output.root_dir().join("compiler-rt");
+        if !builder.config.dry_run() {
+            assert!(
+                ci_llvm_compiler_rt.exists(),
+                "compiler-rt sources not found in LLVM downloaded from CI at {ci_llvm_compiler_rt:?}"
+            );
         }
+        return ci_llvm_compiler_rt;
     }
 
     // Otherwise, fall back to requiring the LLVM submodule.
@@ -1387,9 +1390,7 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetS
     // (i.e. it's already built or is downloadable), we prefer to maintain a
     // consistent environment between check and non-check builds.
     if builder.config.llvm_enabled(target) {
-        let building_llvm_is_expensive =
-            crate::core::build_steps::llvm::prebuilt_llvm_config(builder, target, false)
-                .should_build();
+        let building_llvm_is_expensive = prebuilt_llvm_output(builder, target).is_none();
 
         let skip_llvm = (builder.kind == Kind::Check) && building_llvm_is_expensive;
         if !skip_llvm {
@@ -1419,13 +1420,13 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetS
 /// Note that this has the side-effect of _building LLVM_, which is sometimes
 /// unwanted (e.g. for check builds).
 fn rustc_llvm_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelection) {
-    if builder.config.is_rust_llvm(target) {
+    let llvm_output = builder.ensure(llvm::Llvm { target });
+    if builder.config.is_rust_llvm(&llvm_output, target) {
         cargo.env("LLVM_RUSTLLVM", "1");
     }
     if builder.config.llvm_enzyme {
         cargo.env("LLVM_ENZYME", "1");
     }
-    let llvm_output = builder.ensure(llvm::Llvm { target });
     if builder.config.llvm_offload {
         builder.ensure(llvm::OmpOffload { target });
         cargo.env("LLVM_OFFLOAD", "1");
@@ -1484,7 +1485,7 @@ fn rustc_llvm_env(builder: &Builder<'_>, cargo: &mut Cargo, target: TargetSelect
         );
         cargo.env("LLVM_STATIC_STDCPP", file);
     }
-    if builder.llvm_link_shared() {
+    if llvm_output.link_shared() {
         cargo.env("LLVM_LINK_SHARED", "1");
     }
     if builder.config.llvm_use_libcxx {
@@ -2185,7 +2186,7 @@ impl CommandLineStep for Assemble {
                     let src_path = llvm_bin_dir.join(&tool_exe);
 
                     // When using `download-ci-llvm`, some of the tools may not exist, so skip trying to copy them.
-                    if !src_path.exists() && builder.config.llvm_from_ci {
+                    if !src_path.exists() && builder.config.llvm_ci_mode.download_from_ci() {
                         eprintln!("{} does not exist; skipping copy", src_path.display());
                         continue;
                     }

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

@@ -24,6 +24,9 @@ use crate::core::build_steps::compile::{
 };
 use crate::core::build_steps::doc::DocumentationFormat;
 use crate::core::build_steps::gcc::GccTargetPair;
+use crate::core::build_steps::llvm::{
+    LLVM_CI_LINK_TYPE_PATH, LlvmBuildStatus, get_llvm_build_status,
+};
 use crate::core::build_steps::tool::{
     self, RustcPrivateCompilers, ToolTargetBuildMode, get_tool_target_compiler,
 };
@@ -2474,6 +2477,7 @@ fn install_llvm_file(
 )]
 fn maybe_install_llvm(
     builder: &Builder<'_>,
+    llvm: &LlvmBuildStatus,
     target: TargetSelection,
     dst_libdir: &Path,
     install_symlink: bool,
@@ -2494,7 +2498,14 @@ fn maybe_install_llvm(
     //
     // If the LLVM is coming from ourselves (just from CI) though, we
     // still want to install it, as it otherwise won't be available.
-    if builder.config.is_system_llvm(target) {
+
+    // FIXME: this should be simplified once we stop pre-setting LLVM CI llvm-config during
+    // config parsing.
+    let is_system_llvm =
+        builder.config.target_config.get(&target).and_then(|t| t.llvm_config.as_ref()).is_some()
+            && !(builder.config.llvm_ci_mode.download_from_ci()
+                && builder.config.is_host_target(target));
+    if is_system_llvm {
         trace!("system LLVM requested, no install");
         return false;
     }
@@ -2504,7 +2515,7 @@ fn maybe_install_llvm(
     // clear why this is the case, though. llvm-config will emit the versioned
     // paths and we don't want those in the sysroot (as we're expecting
     // unversioned paths).
-    if target.contains("apple-darwin") && builder.llvm_link_shared() {
+    if target.contains("apple-darwin") && llvm.llvm_output().link_shared() {
         let src_libdir = builder.llvm_out(target).join("lib");
         let llvm_dylib_path = src_libdir.join("libLLVM.dylib");
         if llvm_dylib_path.exists() {
@@ -2532,7 +2543,7 @@ fn maybe_install_llvm(
         !builder.config.dry_run()
     } else if let llvm::LlvmBuildStatus::AlreadyBuilt(llvm::LlvmOutput {
         host_llvm_config, ..
-    }) = llvm::prebuilt_llvm_config(builder, target, true)
+    }) = llvm
     {
         trace!("LLVM already built, installing LLVM files");
         let mut cmd = command(host_llvm_config);
@@ -2565,19 +2576,23 @@ fn maybe_install_llvm(
         name = "maybe_install_llvm_target",
         skip_all,
         fields(
-            llvm_link_shared = ?builder.llvm_link_shared(),
             target = ?target,
             sysroot = ?sysroot,
         ),
     ),
 )]
 pub fn maybe_install_llvm_target(builder: &Builder<'_>, target: TargetSelection, sysroot: &Path) {
     let dst_libdir = sysroot.join("lib/rustlib").join(target).join("lib");
+
+    // We need to figure out the link mode from a LLVM, if it is provided, but without forcing it
+    // to be built if it isn't.
+    let config = get_llvm_build_status(builder, target);
+
     // We do not need to copy LLVM files into the sysroot if it is not
     // dynamically linked; it is already included into librustc_llvm
     // statically.
-    if builder.llvm_link_shared() {
-        maybe_install_llvm(builder, target, &dst_libdir, false);
+    if config.llvm_output().link_shared() {
+        maybe_install_llvm(builder, &config, target, &dst_libdir, false);
     }
 }
 
@@ -2589,26 +2604,30 @@ pub fn maybe_install_llvm_target(builder: &Builder<'_>, target: TargetSelection,
         name = "maybe_install_llvm_runtime",
         skip_all,
         fields(
-            llvm_link_shared = ?builder.llvm_link_shared(),
             target = ?target,
             sysroot = ?sysroot,
         ),
     ),
 )]
 pub fn maybe_install_llvm_runtime(builder: &Builder<'_>, target: TargetSelection, sysroot: &Path) {
     let dst_libdir = sysroot.join(builder.libdir_relative(Compiler::new(1, target)));
+
+    // We need to figure out the link mode from a LLVM, if it is provided, but without forcing it
+    // to be built if it isn't.
+    let config = get_llvm_build_status(builder, target);
+
     // We do not need to copy LLVM files into the sysroot if it is not
     // dynamically linked; it is already included into librustc_llvm
     // statically.
-    if builder.llvm_link_shared() {
-        maybe_install_llvm(builder, target, &dst_libdir, false);
+    if config.llvm_output().link_shared() {
+        maybe_install_llvm(builder, &config, target, &dst_libdir, false);
 
         // To workaround lack of rpath on Windows, we bundle another copy of
         // the LLVM DLL to make rust-lld and llvm-tools work when `sysroot/bin`
         //  is missing from PATH, i.e. when they not launched by rustc.
         if target.triple.contains("windows") {
             let dst_libdir = sysroot.join("lib/rustlib").join(target).join("bin");
-            maybe_install_llvm(builder, target, &dst_libdir, false);
+            maybe_install_llvm(builder, &config, target, &dst_libdir, false);
         }
     }
 }
@@ -2670,7 +2689,7 @@ impl CommandLineStep for LlvmTools {
 
         // Run only if a custom llvm-config is not used
         if let Some(config) = builder.config.target_config.get(&target)
-            && !builder.config.llvm_from_ci
+            && !builder.config.llvm_ci_mode.download_from_ci()
             && config.llvm_config.is_some()
         {
             builder.info(&format!("Skipping LlvmTools ({target}): external LLVM"));
@@ -2694,7 +2713,7 @@ impl CommandLineStep for LlvmTools {
             for tool in tools_to_install(&builder.paths) {
                 let exe = src_bindir.join(exe(tool, target));
                 // When using `download-ci-llvm`, some of the tools may not exist, so skip trying to copy them.
-                if !exe.exists() && builder.config.llvm_from_ci {
+                if !exe.exists() && builder.config.llvm_ci_mode.download_from_ci() {
                     eprintln!("{} does not exist; skipping copy", exe.display());
                     continue;
                 }
@@ -2960,9 +2979,13 @@ impl CommandLineStep for RustDev {
         // of `rustc-dev` to support the inherited `-lLLVM` when using the
         // compiler libraries.
         let dst_libdir = tarball.image_dir().join("lib");
-        maybe_install_llvm(builder, target, &dst_libdir, true);
-        let link_type = if builder.llvm_link_shared() { "dynamic" } else { "static" };
-        t!(std::fs::write(tarball.image_dir().join("link-type.txt"), link_type), dst_libdir);
+
+        let config = get_llvm_build_status(builder, target);
+        maybe_install_llvm(builder, &config, target, &dst_libdir, true);
+
+        // Store the link type, so that it can be read by bootstrap after the archive is downloaded
+        let link_type = if llvm_output.link_shared() { "dynamic" } else { "static" };
+        t!(std::fs::write(tarball.image_dir().join(LLVM_CI_LINK_TYPE_PATH), link_type), dst_libdir);
 
         // Copy the `compiler-rt` source, so that `library/profiler_builtins`
         // can potentially use it to build the profiler runtime without needing