From c39929ce189d0246fe25380b6e5aa7e43786fd22 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Mon, 8 Apr 2024 15:58:26 +0000 Subject: [PATCH 1/7] remove some unnecessary lifetimes --- compiler/rustc_codegen_ssa/src/back/link.rs | 42 ++++++++++----------- 1 file changed, 19 insertions(+), 23 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs index ac278de02af2e..019f2e6170a8f 100644 --- a/compiler/rustc_codegen_ssa/src/back/link.rs +++ b/compiler/rustc_codegen_ssa/src/back/link.rs @@ -71,8 +71,8 @@ pub fn ensure_removed(dcx: &DiagCtxt, path: &Path) { /// Performs the linkage portion of the compilation phase. This will generate all /// of the requested outputs for this compilation session. -pub fn link_binary<'a>( - sess: &'a Session, +pub fn link_binary( + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, codegen_results: &CodegenResults, outputs: &OutputFilenames, @@ -464,9 +464,9 @@ fn link_rlib<'a>( /// then the CodegenResults value contains one NativeLib instance for each block. However, the /// linker appears to expect only a single import library for each library used, so we need to /// collate the symbols together by library name before generating the import libraries. -fn collate_raw_dylibs<'a, 'b>( - sess: &'a Session, - used_libraries: impl IntoIterator, +fn collate_raw_dylibs<'a>( + sess: &Session, + used_libraries: impl IntoIterator, ) -> Result)>, ErrorGuaranteed> { // Use index maps to preserve original order of imports and libraries. let mut dylib_table = FxIndexMap::>::default(); @@ -513,8 +513,8 @@ fn collate_raw_dylibs<'a, 'b>( /// /// There's no need to include metadata in a static archive, so ensure to not link in the metadata /// object file (and also don't prepare the archive with a metadata file). -fn link_staticlib<'a>( - sess: &'a Session, +fn link_staticlib( + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, codegen_results: &CodegenResults, out_filename: &Path, @@ -626,11 +626,7 @@ fn link_staticlib<'a>( /// Use `thorin` (rust implementation of a dwarf packaging utility) to link DWARF objects into a /// DWARF package. -fn link_dwarf_object<'a>( - sess: &'a Session, - cg_results: &CodegenResults, - executable_out_filename: &Path, -) { +fn link_dwarf_object(sess: &Session, cg_results: &CodegenResults, executable_out_filename: &Path) { let mut dwp_out_filename = executable_out_filename.to_path_buf().into_os_string(); dwp_out_filename.push(".dwp"); debug!(?dwp_out_filename, ?executable_out_filename); @@ -734,8 +730,8 @@ fn link_dwarf_object<'a>( /// /// This will invoke the system linker/cc to create the resulting file. This links to all upstream /// files as well. -fn link_natively<'a>( - sess: &'a Session, +fn link_natively( + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, crate_type: CrateType, out_filename: &Path, @@ -1099,8 +1095,8 @@ fn link_natively<'a>( Ok(()) } -fn strip_symbols_with_external_utility<'a>( - sess: &'a Session, +fn strip_symbols_with_external_utility( + sess: &Session, util: &str, out_filename: &Path, option: Option<&str>, @@ -2108,10 +2104,10 @@ fn add_rpath_args( /// to the linking process as a whole. /// Order-independent options may still override each other in order-dependent fashion, /// e.g `--foo=yes --foo=no` may be equivalent to `--foo=no`. -fn linker_with_args<'a>( +fn linker_with_args( path: &Path, flavor: LinkerFlavor, - sess: &'a Session, + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, crate_type: CrateType, tmpdir: &Path, @@ -2643,9 +2639,9 @@ fn add_local_native_libraries( ); } -fn add_upstream_rust_crates<'a>( +fn add_upstream_rust_crates( cmd: &mut dyn Linker, - sess: &'a Session, + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, codegen_results: &CodegenResults, crate_type: CrateType, @@ -2782,7 +2778,7 @@ fn add_upstream_native_libraries( // file generated by the MSVC linker. See https://github.com/rust-lang/rust/issues/112586. // // The returned path will always have `fix_windows_verbatim_for_gcc()` applied to it. -fn rehome_sysroot_lib_dir<'a>(sess: &'a Session, lib_dir: &Path) -> PathBuf { +fn rehome_sysroot_lib_dir(sess: &Session, lib_dir: &Path) -> PathBuf { let sysroot_lib_path = sess.target_filesearch(PathKind::All).get_lib_path(); let canonical_sysroot_lib_path = { try_canonicalize(&sysroot_lib_path).unwrap_or_else(|_| sysroot_lib_path.clone()) }; @@ -2815,9 +2811,9 @@ fn rehome_sysroot_lib_dir<'a>(sess: &'a Session, lib_dir: &Path) -> PathBuf { // Note, however, that if we're not doing LTO we can just pass the rlib // blindly to the linker (fast) because it's fine if it's not actually // included as we're at the end of the dependency chain. -fn add_static_crate<'a>( +fn add_static_crate( cmd: &mut dyn Linker, - sess: &'a Session, + sess: &Session, archive_builder_builder: &dyn ArchiveBuilderBuilder, codegen_results: &CodegenResults, tmpdir: &Path, From 695aac2c02f7073557222083007bedbda8d685da Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Mon, 8 Apr 2024 21:35:29 +0000 Subject: [PATCH 2/7] introduce `LinkerFeatures` They are a flexible complementary mechanism to linker flavors, that also avoid the combinatorial explosion of mapping linking features to actual linker flavors. --- compiler/rustc_target/src/spec/mod.rs | 52 +++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs index e94c7f3cc582d..05e3c8b964130 100644 --- a/compiler/rustc_target/src/spec/mod.rs +++ b/compiler/rustc_target/src/spec/mod.rs @@ -698,6 +698,58 @@ impl ToJson for LinkSelfContainedComponents { } } +bitflags::bitflags! { + /// The `-Z linker-features` components that can individually be enabled or disabled. + /// + /// They are feature flags intended to be a more flexible mechanism than linker flavors, and + /// also to prevent a combinatorial explosion of flavors whenever a new linker feature is + /// required. These flags are "generic", in the sense that they can work on multiple targets on + /// the CLI. Otherwise, one would have to select different linkers flavors for each target. + /// + /// Here are some examples of the advantages they offer: + /// - default feature sets for principal flavors, or for specific targets. + /// - flavor-specific features: for example, clang offers automatic cross-linking with + /// `--target`, which gcc-style compilers don't support. The *flavor* is still a C/C++ + /// compiler, and we don't need to multiply the number of flavors for this use-case. Instead, + /// we can have a single `+target` feature. + /// - umbrella features: for example if clang accumulates more features in the future than just + /// the `+target` above. That could be modeled as `+clang`. + /// - niche features for resolving specific issues: for example, on Apple targets the linker + /// flag implementing the `as-needed` native link modifier (#99424) is only possible on + /// sufficiently recent linker versions. + /// - still allows for discovery and automation, for example via feature detection. This can be + /// useful in exotic environments/build systems. + #[derive(Clone, Copy, PartialEq, Eq, Default)] + pub struct LinkerFeatures: u8 { + /// Invoke the linker via a C/C++ compiler (e.g. on most unix targets). + const CC = 1 << 0; + /// Use the lld linker, either the system lld or the self-contained linker `rust-lld`. + const LLD = 1 << 1; + } +} +rustc_data_structures::external_bitflags_debug! { LinkerFeatures } + +impl LinkerFeatures { + /// Parses a single `-Z linker-features` well-known feature, not a set of flags. + pub fn from_str(s: &str) -> Option { + Some(match s { + "cc" => LinkerFeatures::CC, + "lld" => LinkerFeatures::LLD, + _ => return None, + }) + } + + /// Returns whether the `lld` linker feature is enabled. + pub fn is_lld_enabled(self) -> bool { + self.contains(LinkerFeatures::LLD) + } + + /// Returns whether the `cc` linker feature is enabled. + pub fn is_cc_enabled(self) -> bool { + self.contains(LinkerFeatures::CC) + } +} + #[derive(Clone, Copy, Debug, PartialEq, Hash, Encodable, Decodable, HashStable_Generic)] pub enum PanicStrategy { Unwind, From 2398d8cf08afc60d7420f272b011908dad3a29e5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Mon, 8 Apr 2024 21:40:44 +0000 Subject: [PATCH 3/7] add `-Z linker-features` to toggle lld on the CLI but don't expose `+/-cc` yet --- compiler/rustc_session/src/config.rs | 44 ++++++++++++++++++++++++++- compiler/rustc_session/src/options.rs | 20 ++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs index a4919b25fe35e..34acb4ea10f82 100644 --- a/compiler/rustc_session/src/config.rs +++ b/compiler/rustc_session/src/config.rs @@ -18,7 +18,7 @@ use rustc_feature::UnstableFeatures; use rustc_span::edition::{Edition, DEFAULT_EDITION, EDITION_NAME_LIST, LATEST_STABLE_EDITION}; use rustc_span::source_map::FilePathMapping; use rustc_span::{FileName, FileNameDisplayPreference, RealFileName, SourceFileHashAlgorithm}; -use rustc_target::spec::LinkSelfContainedComponents; +use rustc_target::spec::{LinkSelfContainedComponents, LinkerFeatures}; use rustc_target::spec::{SplitDebuginfo, Target, TargetTriple}; use std::collections::btree_map::{ Iter as BTreeMapIter, Keys as BTreeMapKeysIter, Values as BTreeMapValuesIter, @@ -292,6 +292,48 @@ impl LinkSelfContained { } } +/// The different values that `-Z linker-features` can take on the CLI: a list of individually +/// enabled or disabled features used during linking. +/// +/// There is no need to enable or disable them in bulk. Each feature is fine-grained, and can be +/// used to turn `LinkerFeatures` on or off, without needing to change the linker flavor: +/// - using the system lld, or the self-contained `rust-lld` linker +/// - using a C/C++ compiler to drive the linker (not yet exposed on the CLI) +/// - etc. +#[derive(Default, Copy, Clone, PartialEq, Debug)] +pub struct LinkerFeaturesCli { + /// The linker features that are enabled on the CLI, using the `+feature` syntax. + pub enabled: LinkerFeatures, + + /// The linker features that are disabled on the CLI, using the `-feature` syntax. + pub disabled: LinkerFeatures, +} + +impl LinkerFeaturesCli { + /// Accumulates an enabled or disabled feature as specified on the CLI, if possible. + /// For example: `+lld`, and `-lld`. + pub(crate) fn handle_cli_feature(&mut self, feature: &str) -> Option<()> { + // Duplicate flags are reduced as we go, the last occurrence wins: + // `+feature,-feature,+feature` only enables the feature, and does not record it as both + // enabled and disabled on the CLI. + // We also only expose `+/-lld` at the moment, as it's currenty the only implemented linker + // feature and toggling `LinkerFeatures::CC` would be a noop. + match feature { + "+lld" => { + self.enabled.insert(LinkerFeatures::LLD); + self.disabled.remove(LinkerFeatures::LLD); + Some(()) + } + "-lld" => { + self.disabled.insert(LinkerFeatures::LLD); + self.enabled.remove(LinkerFeatures::LLD); + Some(()) + } + _ => None, + } + } +} + /// Used with `-Z assert-incr-state`. #[derive(Clone, Copy, PartialEq, Hash, Debug)] pub enum IncrementalStateAssertion { diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs index 5e7c246509771..963c9558c170c 100644 --- a/compiler/rustc_session/src/options.rs +++ b/compiler/rustc_session/src/options.rs @@ -426,6 +426,8 @@ mod desc { "one of supported split dwarf modes (`split` or `single`)"; pub 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 const parse_linker_features: &str = + "a list of enabled (`+` prefix) and disabled (`-` prefix) features: `lld`"; pub const parse_polonius: &str = "either no value or `legacy` (the default), or `next`"; pub const parse_stack_protector: &str = "one of (`none` (default), `basic`, `strong`, or `all`)"; @@ -1269,6 +1271,22 @@ mod parse { true } + /// Parse a comma-separated list of enabled and disabled linker features. + pub(crate) fn parse_linker_features(slot: &mut LinkerFeaturesCli, v: Option<&str>) -> bool { + match v { + Some(s) => { + for feature in s.split(',') { + if slot.handle_cli_feature(feature).is_none() { + return false; + } + } + + true + } + None => false, + } + } + pub(crate) fn parse_wasi_exec_model(slot: &mut Option, v: Option<&str>) -> bool { match v { Some("command") => *slot = Some(WasiExecModel::Command), @@ -1721,6 +1739,8 @@ options! { "link native libraries in the linker invocation (default: yes)"), link_only: bool = (false, parse_bool, [TRACKED], "link the `.rlink` file generated by `-Z no-link` (default: no)"), + linker_features: LinkerFeaturesCli = (LinkerFeaturesCli::default(), parse_linker_features, [UNTRACKED], + "a comma-separated list of linker features to enable (+) or disable (-): `lld`"), lint_mir: bool = (false, parse_bool, [UNTRACKED], "lint MIR before and after each transformation"), llvm_module_flag: Vec<(String, u32, String)> = (Vec::new(), parse_llvm_module_flag, [TRACKED], From 11b6d40a98721a8d06177aa05e5d7725aed5dc91 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Fri, 12 Apr 2024 09:40:12 +0000 Subject: [PATCH 4/7] make CLI linker features influence the linker flavor While they're isomorphic, we can flip the lld component where applicable, so that downstream doesn't have to check both the flavor and the linker features. --- compiler/rustc_codegen_ssa/src/back/link.rs | 29 +++++++++++++++++++-- compiler/rustc_target/src/spec/mod.rs | 22 ++++++++++++++++ 2 files changed, 49 insertions(+), 2 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs index 019f2e6170a8f..ca2453b0b03b1 100644 --- a/compiler/rustc_codegen_ssa/src/back/link.rs +++ b/compiler/rustc_codegen_ssa/src/back/link.rs @@ -11,6 +11,7 @@ use rustc_metadata::fs::{copy_to_stdout, emit_wrapper_file, METADATA_FILENAME}; use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile; use rustc_middle::middle::dependency_format::Linkage; use rustc_middle::middle::exported_symbols::SymbolExportKind; +use rustc_session::config::LinkerFeaturesCli; use rustc_session::config::{self, CFGuard, CrateType, DebugInfo, OutFileName, Strip}; use rustc_session::config::{OutputFilenames, OutputType, PrintKind, SplitDwarfKind}; use rustc_session::cstore::DllImport; @@ -22,10 +23,10 @@ use rustc_session::utils::NativeLibKind; use rustc_session::{filesearch, Session}; use rustc_span::symbol::Symbol; use rustc_target::spec::crt_objects::CrtObjects; -use rustc_target::spec::LinkSelfContainedComponents; use rustc_target::spec::LinkSelfContainedDefault; use rustc_target::spec::LinkerFlavorCli; use rustc_target::spec::{Cc, LinkOutputKind, LinkerFlavor, Lld, PanicStrategy}; +use rustc_target::spec::{LinkSelfContainedComponents, LinkerFeatures}; use rustc_target::spec::{RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo}; use super::archive::{ArchiveBuilder, ArchiveBuilderBuilder}; @@ -1333,7 +1334,9 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) { sess: &Session, linker: Option, flavor: Option, + features: LinkerFeaturesCli, ) -> Option<(PathBuf, LinkerFlavor)> { + let flavor = flavor.map(|flavor| adjust_flavor_to_features(flavor, features)); match (linker, flavor) { (Some(linker), Some(flavor)) => Some((linker, flavor)), // only the linker flavor is known; use the default linker for the selected flavor @@ -1381,12 +1384,33 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) { sess.dcx().emit_fatal(errors::LinkerFileStem); }); let flavor = sess.target.linker_flavor.with_linker_hints(stem); + let flavor = adjust_flavor_to_features(flavor, features); Some((linker, flavor)) } (None, None) => None, } } + // While linker flavors and linker features are isomorphic (and thus targets don't need to + // define features separately), we use the flavor as the root piece of data and have the + // linker-features CLI flag influence *that*, so that downstream code does not have to check for + // both yet. + fn adjust_flavor_to_features( + flavor: LinkerFlavor, + features: LinkerFeaturesCli, + ) -> LinkerFlavor { + // Note: a linker feature cannot be both enabled and disabled on the CLI. + if features.enabled.contains(LinkerFeatures::LLD) { + flavor.with_lld_enabled() + } else if features.disabled.contains(LinkerFeatures::LLD) { + flavor.with_lld_disabled() + } else { + flavor + } + } + + let features = sess.opts.unstable_opts.linker_features; + // linker and linker flavor specified via command line have precedence over what the target // specification specifies let linker_flavor = match sess.opts.cg.linker_flavor { @@ -1400,7 +1424,7 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) { .linker_flavor .map(|flavor| sess.target.linker_flavor.with_cli_hints(flavor)), }; - if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), linker_flavor) { + if let Some(ret) = infer_from(sess, sess.opts.cg.linker.clone(), linker_flavor, features) { return ret; } @@ -1408,6 +1432,7 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) { sess, sess.target.linker.as_deref().map(PathBuf::from), Some(sess.target.linker_flavor), + features, ) { return ret; } diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs index 05e3c8b964130..3a69b19ee609c 100644 --- a/compiler/rustc_target/src/spec/mod.rs +++ b/compiler/rustc_target/src/spec/mod.rs @@ -448,6 +448,28 @@ impl LinkerFlavor { | LinkerFlavor::Ptx => false, } } + + /// For flavors with an `Lld` component, ensure it's enabled. Otherwise, returns the given + /// flavor unmodified. + pub fn with_lld_enabled(self) -> LinkerFlavor { + match self { + LinkerFlavor::Gnu(cc, Lld::No) => LinkerFlavor::Gnu(cc, Lld::Yes), + LinkerFlavor::Darwin(cc, Lld::No) => LinkerFlavor::Darwin(cc, Lld::Yes), + LinkerFlavor::Msvc(Lld::No) => LinkerFlavor::Msvc(Lld::Yes), + _ => self, + } + } + + /// For flavors with an `Lld` component, ensure it's disabled. Otherwise, returns the given + /// flavor unmodified. + pub fn with_lld_disabled(self) -> LinkerFlavor { + match self { + LinkerFlavor::Gnu(cc, Lld::Yes) => LinkerFlavor::Gnu(cc, Lld::No), + LinkerFlavor::Darwin(cc, Lld::Yes) => LinkerFlavor::Darwin(cc, Lld::No), + LinkerFlavor::Msvc(Lld::Yes) => LinkerFlavor::Msvc(Lld::No), + _ => self, + } + } } macro_rules! linker_flavor_cli_impls { From 5359d9c02a39a2db780ff291923ac7ecb9b3975b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Mon, 8 Apr 2024 21:53:22 +0000 Subject: [PATCH 5/7] test self-contained linking via `-Zlinker-features=+lld` --- tests/run-make/rust-lld/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tests/run-make/rust-lld/Makefile b/tests/run-make/rust-lld/Makefile index f8526530d4da3..50752391e2804 100644 --- a/tests/run-make/rust-lld/Makefile +++ b/tests/run-make/rust-lld/Makefile @@ -4,5 +4,5 @@ include ../tools.mk # needs-rust-lld # ignore-s390x lld does not yet support s390x as target all: - RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Clink-self-contained=+linker -Clinker-flavor=gnu-lld-cc -Zunstable-options -Clink-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt + RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Clink-self-contained=+linker -Zlinker-features=+lld -Zunstable-options -Clink-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt $(CGREP) -e "^LLD [0-9]+\.[0-9]+\.[0-9]+" < $(TMPDIR)/output.txt From 317d0bdd63d9a2ac174451ee0be76398a1bf704a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Mon, 8 Apr 2024 22:16:37 +0000 Subject: [PATCH 6/7] document `-Zlinker-features` in the unstable book --- .../src/compiler-flags/linker-features.md | 35 +++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 src/doc/unstable-book/src/compiler-flags/linker-features.md diff --git a/src/doc/unstable-book/src/compiler-flags/linker-features.md b/src/doc/unstable-book/src/compiler-flags/linker-features.md new file mode 100644 index 0000000000000..643fcf7c6d7e0 --- /dev/null +++ b/src/doc/unstable-book/src/compiler-flags/linker-features.md @@ -0,0 +1,35 @@ +# `linker-features` + +-------------------- + +The `-Zlinker-features` compiler flag allows enabling or disabling specific features used during +linking, and is intended to be stabilized under the codegen options as `-Clinker-features`. + +These feature flags are a flexible extension mechanism that is complementary to linker flavors, +designed to avoid the combinatorial explosion of having to create a new set of flavors for each +linker feature we'd want to use. + +For example, this design allows: +- default feature sets for principal flavors, or for specific targets. +- flavor-specific features: for example, clang offers automatic cross-linking with `--target`, which + gcc-style compilers don't support. The *flavor* is still a C/C++ compiler, and we don't want to + multiply the number of flavors for this use-case. Instead, we can have a single `+target` feature. +- umbrella features: for example, if clang accumulates more features in the future than just the + `+target` above. That could be modeled as `+clang`. +- niche features for resolving specific issues: for example, on Apple targets the linker flag + implementing the `as-needed` native link modifier (#99424) is only possible on sufficiently recent + linker versions. +- still allows for discovery and automation, for example via feature detection. This can be useful + in exotic environments/build systems. + +The flag accepts a comma-separated list of features, individually enabled (`+features`) or disabled +(`-features`), though currently only one is exposed on the CLI: +- `lld`: to toggle using the lld linker, either the system-installed binary, or the self-contained + `rust-lld` linker. + +As described above, this list is intended to grow in the future. + +One of the most common uses of this flag will be to toggle self-contained linking with `rust-lld` on +and off: `-Clinker-features=+lld -Clink-self-contained=+linker` will use the toolchain's `rust-lld` +as the linker. Inversely, `-Clinker-features=-lld` would opt out of that, if the current target had +self-contained linking enabled by default. From dee834b8a652ea867dca20192400f7331b830a7e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Wed, 10 Apr 2024 16:32:45 +0000 Subject: [PATCH 7/7] test duplicate features, that the last `+/-lld` on the CLI wins --- tests/run-make/rust-lld/Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tests/run-make/rust-lld/Makefile b/tests/run-make/rust-lld/Makefile index 50752391e2804..1ecac479f4147 100644 --- a/tests/run-make/rust-lld/Makefile +++ b/tests/run-make/rust-lld/Makefile @@ -6,3 +6,7 @@ include ../tools.mk all: RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Clink-self-contained=+linker -Zlinker-features=+lld -Zunstable-options -Clink-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt $(CGREP) -e "^LLD [0-9]+\.[0-9]+\.[0-9]+" < $(TMPDIR)/output.txt + + # while we're here, also check that the last linker feature flag "wins" + RUSTC_LOG=rustc_codegen_ssa::back::link=info $(RUSTC) -Clink-self-contained=+linker -Zlinker-features=-lld -Zlinker-features=+lld -Zunstable-options -Clink-args=-Wl,-v main.rs 2> $(TMPDIR)/output.txt + $(CGREP) -e "^LLD [0-9]+\.[0-9]+\.[0-9]+" < $(TMPDIR)/output.txt