diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/back')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/link.rs | 114 |
1 files changed, 63 insertions, 51 deletions
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs index 7e839520dfe..c7925be0d7d 100644 --- a/compiler/rustc_codegen_ssa/src/back/link.rs +++ b/compiler/rustc_codegen_ssa/src/back/link.rs @@ -12,7 +12,7 @@ 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::{self, CFGuard, CrateType, DebugInfo, LdImpl, Strip}; +use rustc_session::config::{self, CFGuard, CrateType, DebugInfo, Strip}; use rustc_session::config::{OutputFilenames, OutputType, PrintRequest, SplitDwarfKind}; use rustc_session::cstore::DllImport; use rustc_session::output::{check_file_is_writeable, invalid_output_for_target, out_filename}; @@ -2246,7 +2246,8 @@ fn add_order_independent_options( out_filename: &Path, tmpdir: &Path, ) { - add_gcc_ld_path(cmd, sess, flavor); + // Take care of the flavors and CLI options requesting the `lld` linker. + add_lld_args(cmd, sess, flavor); add_apple_sdk(cmd, sess, flavor); @@ -2948,55 +2949,66 @@ fn get_apple_sdk_root(sdk_name: &str) -> Result<String, errors::AppleSdkRootErro } } -fn add_gcc_ld_path(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) { - if let Some(ld_impl) = sess.opts.unstable_opts.gcc_ld { - if let LinkerFlavor::Gnu(Cc::Yes, _) - | LinkerFlavor::Darwin(Cc::Yes, _) - | LinkerFlavor::WasmLld(Cc::Yes) = flavor - { - match ld_impl { - LdImpl::Lld => { - // Implement the "self-contained" part of -Zgcc-ld - // by adding rustc distribution directories to the tool search path. - for path in sess.get_tools_search_paths(false) { - cmd.arg({ - let mut arg = OsString::from("-B"); - arg.push(path.join("gcc-ld")); - arg - }); - } - // Implement the "linker flavor" part of -Zgcc-ld - // by asking cc to use some kind of lld. - cmd.arg("-fuse-ld=lld"); - - if !flavor.is_gnu() { - // Tell clang to use a non-default LLD flavor. - // Gcc doesn't understand the target option, but we currently assume - // that gcc is not used for Apple and Wasm targets (#97402). - // - // Note that we don't want to do that by default on macOS: e.g. passing a - // 10.7 target to LLVM works, but not to recent versions of clang/macOS, as - // shown in issue #101653 and the discussion in PR #101792. - // - // It could be required in some cases of cross-compiling with - // `-Zgcc-ld=lld`, but this is generally unspecified, and we don't know - // which specific versions of clang, macOS SDK, host and target OS - // combinations impact us here. - // - // So we do a simple first-approximation until we know more of what the - // Apple targets require (and which would be handled prior to hitting this - // `-Zgcc-ld=lld` codepath anyway), but the expectation is that until then - // this should be manually passed if needed. We specify the target when - // targeting a different linker flavor on macOS, and that's also always - // the case when targeting WASM. - if sess.target.linker_flavor != sess.host.linker_flavor { - cmd.arg(format!("--target={}", sess.target.llvm_target)); - } - } - } - } - } else { - sess.emit_fatal(errors::OptionGccOnly); +/// When using the linker flavors opting in to `lld`, or the unstable `-Zgcc-ld=lld` flag, add the +/// necessary paths and arguments to invoke it: +/// - when the self-contained linker flag is active: the build of `lld` distributed with rustc, +/// - or any `lld` available to `cc`. +fn add_lld_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor) { + let unstable_use_lld = sess.opts.unstable_opts.gcc_ld.is_some(); + debug!("add_lld_args requested, flavor: '{flavor:?}', `-Zgcc-ld=lld`: {unstable_use_lld}"); + + // Sanity check: using the old unstable `-Zgcc-ld=lld` option requires a `cc`-using flavor. + let flavor_uses_cc = flavor.uses_cc(); + if unstable_use_lld && !flavor_uses_cc { + sess.emit_fatal(errors::OptionGccOnly); + } + + // If the flavor doesn't use a C/C++ compiler to invoke the linker, or doesn't opt in to `lld`, + // we don't need to do anything. + let use_lld = flavor.uses_lld() || unstable_use_lld; + if !flavor_uses_cc || !use_lld { + return; + } + + // 1. Implement the "self-contained" part of this feature by adding rustc distribution + // directories to the tool's search path. + let self_contained_linker = sess.opts.cg.link_self_contained.linker() || unstable_use_lld; + if self_contained_linker { + for path in sess.get_tools_search_paths(false) { + cmd.arg({ + let mut arg = OsString::from("-B"); + arg.push(path.join("gcc-ld")); + arg + }); + } + } + + // 2. Implement the "linker flavor" part of this feature by asking `cc` to use some kind of + // `lld` as the linker. + cmd.arg("-fuse-ld=lld"); + + if !flavor.is_gnu() { + // Tell clang to use a non-default LLD flavor. + // Gcc doesn't understand the target option, but we currently assume + // that gcc is not used for Apple and Wasm targets (#97402). + // + // Note that we don't want to do that by default on macOS: e.g. passing a + // 10.7 target to LLVM works, but not to recent versions of clang/macOS, as + // shown in issue #101653 and the discussion in PR #101792. + // + // It could be required in some cases of cross-compiling with + // `-Zgcc-ld=lld`, but this is generally unspecified, and we don't know + // which specific versions of clang, macOS SDK, host and target OS + // combinations impact us here. + // + // So we do a simple first-approximation until we know more of what the + // Apple targets require (and which would be handled prior to hitting this + // `-Zgcc-ld=lld` codepath anyway), but the expectation is that until then + // this should be manually passed if needed. We specify the target when + // targeting a different linker flavor on macOS, and that's also always + // the case when targeting WASM. + if sess.target.linker_flavor != sess.host.linker_flavor { + cmd.arg(format!("--target={}", sess.target.llvm_target)); } } } |