diff --git a/config.toml.example b/config.toml.example index c9e17337ee2..c8aff4af8ff 100644 --- a/config.toml.example +++ b/config.toml.example @@ -395,6 +395,11 @@ # rustc to execute. #lld = false +# Indicates whether LLD will be used to link Rust crates during bootstrap on +# supported platforms. The LLD from the bootstrap distribution will be used +# and not the LLD compiled during the bootstrap. +#use-lld = false + # Indicates whether some LLVM tools, like llvm-objdump, will be made available in the # sysroot. #llvm-tools = false diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs index a34ec44566b..46e3e4ef6d1 100644 --- a/src/bootstrap/bin/rustc.rs +++ b/src/bootstrap/bin/rustc.rs @@ -134,6 +134,11 @@ fn main() { cmd.arg(format!("-Clinker={}", host_linker)); } + // Override linker flavor if necessary. + if let Ok(host_linker_flavor) = env::var("RUSTC_HOST_LINKER_FLAVOR") { + cmd.arg(format!("-Clinker-flavor={}", host_linker_flavor)); + } + if let Ok(s) = env::var("RUSTC_HOST_CRT_STATIC") { if s == "true" { cmd.arg("-C").arg("target-feature=+crt-static"); diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs index d9c894aa9c6..008af975c33 100644 --- a/src/bootstrap/builder.rs +++ b/src/bootstrap/builder.rs @@ -694,7 +694,7 @@ impl<'a> Builder<'a> { cmd.env_remove("MAKEFLAGS"); cmd.env_remove("MFLAGS"); - if let Some(linker) = self.linker(compiler.host) { + if let Some(linker) = self.linker(compiler.host, true) { cmd.env("RUSTC_TARGET_LINKER", linker); } cmd @@ -949,10 +949,30 @@ impl<'a> Builder<'a> { } } - if let Some(host_linker) = self.linker(compiler.host) { + // FIXME: Don't use LLD if we're compiling libstd, since it fails to link it. + let can_use_lld = mode != Mode::Std; + + // FIXME: The beta compiler doesn't pick the `lld-link` flavor for `*-pc-windows-msvc` + // Remove `RUSTC_HOST_LINKER_FLAVOR` when this is fixed + let lld_linker_flavor = |linker: &Path, target: Interned| { + compiler.stage == 0 + && linker.file_name() == Some(OsStr::new("rust-lld")) + && target.contains("pc-windows-msvc") + }; + + if let Some(host_linker) = self.linker(compiler.host, can_use_lld) { + if lld_linker_flavor(host_linker, compiler.host) { + cargo.env("RUSTC_HOST_LINKER_FLAVOR", "lld-link"); + } + cargo.env("RUSTC_HOST_LINKER", host_linker); } - if let Some(target_linker) = self.linker(target) { + + if let Some(target_linker) = self.linker(target, can_use_lld) { + if lld_linker_flavor(target_linker, target) { + rustflags.arg("-Clinker-flavor=lld-link"); + } + let target = crate::envify(&target); cargo.env(&format!("CARGO_TARGET_{}_LINKER", target), target_linker); } diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs index 110c8b844d5..8a01bee2208 100644 --- a/src/bootstrap/config.rs +++ b/src/bootstrap/config.rs @@ -83,6 +83,7 @@ pub struct Config { pub llvm_use_linker: Option, pub llvm_allow_old_toolchain: Option, + pub use_lld: bool, pub lld_enabled: bool, pub lldb_enabled: bool, pub llvm_tools_enabled: bool, @@ -322,6 +323,7 @@ struct Rust { save_toolstates: Option, codegen_backends: Option>, lld: Option, + use_lld: Option, llvm_tools: Option, lldb: Option, deny_warnings: Option, @@ -566,6 +568,7 @@ impl Config { if let Some(true) = rust.incremental { config.incremental = true; } + set(&mut config.use_lld, rust.use_lld); set(&mut config.lld_enabled, rust.lld); set(&mut config.lldb_enabled, rust.lldb); set(&mut config.llvm_tools_enabled, rust.llvm_tools); diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs index 1fee3fd9ac1..97552224103 100644 --- a/src/bootstrap/lib.rs +++ b/src/bootstrap/lib.rs @@ -239,9 +239,10 @@ pub struct Build { hosts: Vec>, targets: Vec>, - // Stage 0 (downloaded) compiler and cargo or their local rust equivalents + // Stage 0 (downloaded) compiler, lld and cargo or their local rust equivalents initial_rustc: PathBuf, initial_cargo: PathBuf, + initial_lld: PathBuf, // Runtime state filled in later on // C/C++ compilers and archiver for all targets @@ -343,9 +344,18 @@ impl Build { // we always try to use git for LLVM builds let in_tree_llvm_info = channel::GitInfo::new(false, &src.join("src/llvm-project")); + let initial_sysroot = config.initial_rustc.parent().unwrap().parent().unwrap(); + let initial_lld = initial_sysroot + .join("lib") + .join("rustlib") + .join(config.build) + .join("bin") + .join("rust-lld"); + let mut build = Build { initial_rustc: config.initial_rustc.clone(), initial_cargo: config.initial_cargo.clone(), + initial_lld, local_rebuild: config.local_rebuild, fail_fast: config.cmd.fail_fast(), doc_tests: config.cmd.doc_tests(), @@ -810,7 +820,7 @@ impl Build { } /// Returns the path to the linker for the given target if it needs to be overridden. - fn linker(&self, target: Interned) -> Option<&Path> { + fn linker(&self, target: Interned, can_use_lld: bool) -> Option<&Path> { if let Some(linker) = self.config.target_config.get(&target).and_then(|c| c.linker.as_ref()) { Some(linker) @@ -819,6 +829,12 @@ impl Build { && !target.contains("msvc") { Some(self.cc(target)) + } else if can_use_lld + && self.config.use_lld + && target.contains("pc-windows-msvc") + && self.build == target + { + Some(&self.initial_lld) } else { None } diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs index 6adf9ddaf34..189f9e6ccab 100644 --- a/src/bootstrap/test.rs +++ b/src/bootstrap/test.rs @@ -596,7 +596,7 @@ impl Step for RustdocTheme { .env("RUSTDOC_REAL", builder.rustdoc(self.compiler)) .env("RUSTDOC_CRATE_VERSION", builder.rust_version()) .env("RUSTC_BOOTSTRAP", "1"); - if let Some(linker) = builder.linker(self.compiler.host) { + if let Some(linker) = builder.linker(self.compiler.host, true) { cmd.env("RUSTC_TARGET_LINKER", linker); } try_run(builder, &mut cmd); @@ -1035,7 +1035,7 @@ impl Step for Compiletest { flags.push("-Zunstable-options".to_string()); flags.push(builder.config.cmd.rustc_args().join(" ")); - if let Some(linker) = builder.linker(target) { + if let Some(linker) = builder.linker(target, false) { cmd.arg("--linker").arg(linker); }