From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Ismael Luceno Date: Wed, 12 Aug 2026 18:49:43 +0200 Subject: [PATCH] Adjustments for the rust-src component and native musl hosts 1. Don't include libunwind in the rust-src component. The component only needs the standard library sources, and the llvm-project tree is removed from the sources before building. 2. Use the system toolchain for musl targets on native musl hosts. rustc ships its own copies of the musl CRT objects, libc.a and an LLVM libunwind build, and links musl targets in "self-contained" mode, so that a glibc host can produce musl binaries without a musl toolchain. On a native musl system that indirection is unnecessary: the system toolchain already provides those objects, and it's the only one guaranteed to match the installed libc. It also forces bootstrap to build the vendored copies out of the llvm-project tree. Gate the self-contained behaviour on the host environment, so that cross-compilation from glibc hosts keeps working unchanged, and default musl targets to dynamic linking on a native musl host, as the system toolchain does for every other language. Upstream-Status: Pending Signed-off-by: Ismael Luceno --- compiler/rustc_target/src/spec/base/linux_musl.rs | 11 ++++++++++ compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs | 5 ++-- compiler/rustc_target/src/spec/targets/i586_unknown_linux_musl.rs | 5 ++-- compiler/rustc_target/src/spec/targets/i686_unknown_linux_musl.rs | 5 ++-- compiler/rustc_target/src/spec/targets/powerpc64le_unknown_linux_musl.rs | 5 ++-- compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_musl.rs | 5 ++-- src/bootstrap/src/core/build_steps/dist.rs | 3 -- src/bootstrap/src/core/config/target_selection.rs | 4 ++- 8 files changed, 30 insertions(+), 13 deletions(-) diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs index cfcb144..529be48 100644 --- a/src/bootstrap/src/core/build_steps/dist.rs +++ b/src/bootstrap/src/core/build_steps/dist.rs @@ -1065,7 +1108,6 @@ fn copy_src_dirs( static LLVM_PROJECTS: &[&str] = &[ "llvm-project/clang", - "llvm-project/libunwind", "llvm-project/lld", "llvm-project/lldb", "llvm-project/llvm", @@ -1191,7 +1238,7 @@ impl Step for Src { copy_src_dirs( builder, &builder.src, - &["library", "src/llvm-project/libunwind"], + &["library"], &[ // not needed and contains symlinks which rustup currently // chokes on when unpacking. diff --git a/compiler/rustc_target/src/spec/base/linux_musl.rs b/compiler/rustc_target/src/spec/base/linux_musl.rs index cfcb144..529be48 100644 --- a/compiler/rustc_target/src/spec/base/linux_musl.rs +++ b/compiler/rustc_target/src/spec/base/linux_musl.rs @@ -1,6 +1,17 @@ use crate::spec::{Env, LinkSelfContainedDefault, TargetOptions, base, crt_objects}; pub(crate) fn opts() -> TargetOptions { + // On a native musl host the system toolchain provides the CRT objects and + // the unwinder, and it is the only one guaranteed to match the installed + // libc, so link against it instead of the copies shipped with rustc. + if cfg!(target_env = "musl") { + return TargetOptions { + env: Env::Musl, + link_self_contained: LinkSelfContainedDefault::False, + ..base::linux::opts() + }; + } + TargetOptions { env: Env::Musl, pre_link_objects_self_contained: crt_objects::pre_musl_self_contained(), diff --git a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs index cfcb144..529be48 100644 --- a/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs +++ b/compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs @@ -14,8 +14,9 @@ | SanitizerSet::MEMORY | SanitizerSet::THREAD; - // FIXME(compiler-team#422): musl targets should be dynamically linked by default. - base.crt_static_default = true; + // FIXME(compiler-team#422): musl targets should be dynamically linked by + // default; a native musl host already is. + base.crt_static_default = !cfg!(target_env = "musl"); Target { llvm_target: "aarch64-unknown-linux-musl".into(), diff --git a/compiler/rustc_target/src/spec/targets/i586_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/i586_unknown_linux_musl.rs index cfcb144..529be48 100644 --- a/compiler/rustc_target/src/spec/targets/i586_unknown_linux_musl.rs +++ b/compiler/rustc_target/src/spec/targets/i586_unknown_linux_musl.rs @@ -5,7 +5,8 @@ base.rustc_abi = None; // overwrite the SSE2 ABI set by the base target base.cpu = "pentium".into(); base.llvm_target = "i586-unknown-linux-musl".into(); - // FIXME(compiler-team#422): musl targets should be dynamically linked by default. - base.crt_static_default = true; + // FIXME(compiler-team#422): musl targets should be dynamically linked by + // default; a native musl host already is. + base.crt_static_default = !cfg!(target_env = "musl"); base } diff --git a/compiler/rustc_target/src/spec/targets/powerpc64le_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/powerpc64le_unknown_linux_musl.rs index cfcb144..529be48 100644 --- a/compiler/rustc_target/src/spec/targets/powerpc64le_unknown_linux_musl.rs +++ b/compiler/rustc_target/src/spec/targets/powerpc64le_unknown_linux_musl.rs @@ -9,8 +9,9 @@ base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m64"]); base.max_atomic_width = Some(64); base.stack_probes = StackProbeType::Inline; - // FIXME(compiler-team#422): musl targets should be dynamically linked by default. - base.crt_static_default = true; + // FIXME(compiler-team#422): musl targets should be dynamically linked by + // default; a native musl host already is. + base.crt_static_default = !cfg!(target_env = "musl"); base.cfg_abi = CfgAbi::ElfV2; base.llvm_abiname = LlvmAbi::ElfV2; diff --git a/compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_musl.rs index cfcb144..529be48 100644 --- a/compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_musl.rs +++ b/compiler/rustc_target/src/spec/targets/x86_64_unknown_linux_musl.rs @@ -16,8 +16,9 @@ | SanitizerSet::MEMORY | SanitizerSet::THREAD; base.supports_xray = true; - // FIXME(compiler-team#422): musl targets should be dynamically linked by default. - base.crt_static_default = true; + // FIXME(compiler-team#422): musl targets should be dynamically linked by + // default; a native musl host already is. + base.crt_static_default = !cfg!(target_env = "musl"); Target { llvm_target: "x86_64-unknown-linux-musl".into(), diff --git a/src/bootstrap/src/core/config/target_selection.rs b/src/bootstrap/src/core/config/target_selection.rs index cfcb144..529be48 100644 --- a/src/bootstrap/src/core/config/target_selection.rs +++ b/src/bootstrap/src/core/config/target_selection.rs @@ -97,7 +97,9 @@ } pub fn needs_crt_begin_end(&self) -> bool { - self.contains("musl") && !self.contains("unikraft") + // A native musl host links against the system toolchain, which already + // provides these objects; see rustc_target's linux_musl base. + !cfg!(target_env = "musl") && self.contains("musl") && !self.contains("unikraft") } /// Path to the file defining the custom target, if any.