diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/codegen_attrs.rs')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/codegen_attrs.rs | 709 |
1 files changed, 709 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs new file mode 100644 index 000000000..8808ad2dc --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -0,0 +1,709 @@ +use rustc_ast::{ast, MetaItemKind, NestedMetaItem}; +use rustc_attr::{list_contains_name, InlineAttr, InstructionSetAttr, OptimizeAttr}; +use rustc_errors::struct_span_err; +use rustc_hir as hir; +use rustc_hir::def::DefKind; +use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE}; +use rustc_hir::{lang_items, weak_lang_items::WEAK_LANG_ITEMS, LangItem}; +use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; +use rustc_middle::mir::mono::Linkage; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::{self as ty, DefIdTree, TyCtxt}; +use rustc_session::{lint, parse::feature_err}; +use rustc_span::{sym, Span}; +use rustc_target::spec::{abi, SanitizerSet}; + +use crate::target_features::from_target_feature; +use crate::{errors::ExpectedUsedSymbol, target_features::check_target_feature_trait_unsafe}; + +fn linkage_by_name(tcx: TyCtxt<'_>, def_id: LocalDefId, name: &str) -> Linkage { + use rustc_middle::mir::mono::Linkage::*; + + // Use the names from src/llvm/docs/LangRef.rst here. Most types are only + // applicable to variable declarations and may not really make sense for + // Rust code in the first place but allow them anyway and trust that the + // user knows what they're doing. Who knows, unanticipated use cases may pop + // up in the future. + // + // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported + // and don't have to be, LLVM treats them as no-ops. + match name { + "appending" => Appending, + "available_externally" => AvailableExternally, + "common" => Common, + "extern_weak" => ExternalWeak, + "external" => External, + "internal" => Internal, + "linkonce" => LinkOnceAny, + "linkonce_odr" => LinkOnceODR, + "private" => Private, + "weak" => WeakAny, + "weak_odr" => WeakODR, + _ => tcx.sess.span_fatal(tcx.def_span(def_id), "invalid linkage specified"), + } +} + +fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs { + if cfg!(debug_assertions) { + let def_kind = tcx.def_kind(did); + assert!( + def_kind.has_codegen_attrs(), + "unexpected `def_kind` in `codegen_fn_attrs`: {def_kind:?}", + ); + } + + let did = did.expect_local(); + let attrs = tcx.hir().attrs(tcx.hir().local_def_id_to_hir_id(did)); + let mut codegen_fn_attrs = CodegenFnAttrs::new(); + if tcx.should_inherit_track_caller(did) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; + } + + let supported_target_features = tcx.supported_target_features(LOCAL_CRATE); + + // In some cases, attribute are only valid on functions, but it's the `check_attr` + // pass that check that they aren't used anywhere else, rather this module. + // In these cases, we bail from performing further checks that are only meaningful for + // functions (such as calling `fn_sig`, which ICEs if given a non-function). We also + // report a delayed bug, just in case `check_attr` isn't doing its job. + let validate_fn_only_attr = |attr_sp| -> bool { + let def_kind = tcx.def_kind(did); + if let DefKind::Fn | DefKind::AssocFn | DefKind::Variant | DefKind::Ctor(..) = def_kind { + true + } else { + tcx.sess.delay_span_bug(attr_sp, "this attribute can only be applied to functions"); + false + } + }; + + let mut inline_span = None; + let mut link_ordinal_span = None; + let mut no_sanitize_span = None; + for attr in attrs.iter() { + if attr.has_name(sym::cold) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD; + } else if attr.has_name(sym::rustc_allocator) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR; + } else if attr.has_name(sym::ffi_returns_twice) { + if tcx.is_foreign_item(did) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_RETURNS_TWICE; + } else { + // `#[ffi_returns_twice]` is only allowed `extern fn`s. + struct_span_err!( + tcx.sess, + attr.span, + E0724, + "`#[ffi_returns_twice]` may only be used on foreign functions" + ) + .emit(); + } + } else if attr.has_name(sym::ffi_pure) { + if tcx.is_foreign_item(did) { + if attrs.iter().any(|a| a.has_name(sym::ffi_const)) { + // `#[ffi_const]` functions cannot be `#[ffi_pure]` + struct_span_err!( + tcx.sess, + attr.span, + E0757, + "`#[ffi_const]` function cannot be `#[ffi_pure]`" + ) + .emit(); + } else { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_PURE; + } + } else { + // `#[ffi_pure]` is only allowed on foreign functions + struct_span_err!( + tcx.sess, + attr.span, + E0755, + "`#[ffi_pure]` may only be used on foreign functions" + ) + .emit(); + } + } else if attr.has_name(sym::ffi_const) { + if tcx.is_foreign_item(did) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::FFI_CONST; + } else { + // `#[ffi_const]` is only allowed on foreign functions + struct_span_err!( + tcx.sess, + attr.span, + E0756, + "`#[ffi_const]` may only be used on foreign functions" + ) + .emit(); + } + } else if attr.has_name(sym::rustc_nounwind) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND; + } else if attr.has_name(sym::rustc_reallocator) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::REALLOCATOR; + } else if attr.has_name(sym::rustc_deallocator) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::DEALLOCATOR; + } else if attr.has_name(sym::rustc_allocator_zeroed) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::ALLOCATOR_ZEROED; + } else if attr.has_name(sym::naked) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NAKED; + } else if attr.has_name(sym::no_mangle) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; + } else if attr.has_name(sym::no_coverage) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE; + } else if attr.has_name(sym::rustc_std_internal_symbol) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; + } else if attr.has_name(sym::used) { + let inner = attr.meta_item_list(); + match inner.as_deref() { + Some([item]) if item.has_name(sym::linker) => { + if !tcx.features().used_with_arg { + feature_err( + &tcx.sess.parse_sess, + sym::used_with_arg, + attr.span, + "`#[used(linker)]` is currently unstable", + ) + .emit(); + } + codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED_LINKER; + } + Some([item]) if item.has_name(sym::compiler) => { + if !tcx.features().used_with_arg { + feature_err( + &tcx.sess.parse_sess, + sym::used_with_arg, + attr.span, + "`#[used(compiler)]` is currently unstable", + ) + .emit(); + } + codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED; + } + Some(_) => { + tcx.sess.emit_err(ExpectedUsedSymbol { span: attr.span }); + } + None => { + // Unfortunately, unconditionally using `llvm.used` causes + // issues in handling `.init_array` with the gold linker, + // but using `llvm.compiler.used` caused a nontrival amount + // of unintentional ecosystem breakage -- particularly on + // Mach-O targets. + // + // As a result, we emit `llvm.compiler.used` only on ELF + // targets. This is somewhat ad-hoc, but actually follows + // our pre-LLVM 13 behavior (prior to the ecosystem + // breakage), and seems to match `clang`'s behavior as well + // (both before and after LLVM 13), possibly because they + // have similar compatibility concerns to us. See + // https://github.com/rust-lang/rust/issues/47384#issuecomment-1019080146 + // and following comments for some discussion of this, as + // well as the comments in `rustc_codegen_llvm` where these + // flags are handled. + // + // Anyway, to be clear: this is still up in the air + // somewhat, and is subject to change in the future (which + // is a good thing, because this would ideally be a bit + // more firmed up). + let is_like_elf = !(tcx.sess.target.is_like_osx + || tcx.sess.target.is_like_windows + || tcx.sess.target.is_like_wasm); + codegen_fn_attrs.flags |= if is_like_elf { + CodegenFnAttrFlags::USED + } else { + CodegenFnAttrFlags::USED_LINKER + }; + } + } + } else if attr.has_name(sym::cmse_nonsecure_entry) { + if validate_fn_only_attr(attr.span) + && !matches!(tcx.fn_sig(did).abi(), abi::Abi::C { .. }) + { + struct_span_err!( + tcx.sess, + attr.span, + E0776, + "`#[cmse_nonsecure_entry]` requires C ABI" + ) + .emit(); + } + if !tcx.sess.target.llvm_target.contains("thumbv8m") { + struct_span_err!(tcx.sess, attr.span, E0775, "`#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M extension") + .emit(); + } + codegen_fn_attrs.flags |= CodegenFnAttrFlags::CMSE_NONSECURE_ENTRY; + } else if attr.has_name(sym::thread_local) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL; + } else if attr.has_name(sym::track_caller) { + if !tcx.is_closure(did.to_def_id()) + && validate_fn_only_attr(attr.span) + && tcx.fn_sig(did).abi() != abi::Abi::Rust + { + struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI") + .emit(); + } + if tcx.is_closure(did.to_def_id()) && !tcx.features().closure_track_caller { + feature_err( + &tcx.sess.parse_sess, + sym::closure_track_caller, + attr.span, + "`#[track_caller]` on closures is currently unstable", + ) + .emit(); + } + codegen_fn_attrs.flags |= CodegenFnAttrFlags::TRACK_CALLER; + } else if attr.has_name(sym::export_name) { + if let Some(s) = attr.value_str() { + if s.as_str().contains('\0') { + // `#[export_name = ...]` will be converted to a null-terminated string, + // so it may not contain any null characters. + struct_span_err!( + tcx.sess, + attr.span, + E0648, + "`export_name` may not contain null characters" + ) + .emit(); + } + codegen_fn_attrs.export_name = Some(s); + } + } else if attr.has_name(sym::target_feature) { + if !tcx.is_closure(did.to_def_id()) + && tcx.fn_sig(did).unsafety() == hir::Unsafety::Normal + { + if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc { + // The `#[target_feature]` attribute is allowed on + // WebAssembly targets on all functions, including safe + // ones. Other targets require that `#[target_feature]` is + // only applied to unsafe functions (pending the + // `target_feature_11` feature) because on most targets + // execution of instructions that are not supported is + // considered undefined behavior. For WebAssembly which is a + // 100% safe target at execution time it's not possible to + // execute undefined instructions, and even if a future + // feature was added in some form for this it would be a + // deterministic trap. There is no undefined behavior when + // executing WebAssembly so `#[target_feature]` is allowed + // on safe functions (but again, only for WebAssembly) + // + // Note that this is also allowed if `actually_rustdoc` so + // if a target is documenting some wasm-specific code then + // it's not spuriously denied. + } else if !tcx.features().target_feature_11 { + let mut err = feature_err( + &tcx.sess.parse_sess, + sym::target_feature_11, + attr.span, + "`#[target_feature(..)]` can only be applied to `unsafe` functions", + ); + err.span_label(tcx.def_span(did), "not an `unsafe` function"); + err.emit(); + } else { + check_target_feature_trait_unsafe(tcx, did, attr.span); + } + } + from_target_feature( + tcx, + attr, + supported_target_features, + &mut codegen_fn_attrs.target_features, + ); + } else if attr.has_name(sym::linkage) { + if let Some(val) = attr.value_str() { + let linkage = Some(linkage_by_name(tcx, did, val.as_str())); + if tcx.is_foreign_item(did) { + codegen_fn_attrs.import_linkage = linkage; + } else { + codegen_fn_attrs.linkage = linkage; + } + } + } else if attr.has_name(sym::link_section) { + if let Some(val) = attr.value_str() { + if val.as_str().bytes().any(|b| b == 0) { + let msg = format!( + "illegal null byte in link_section \ + value: `{}`", + &val + ); + tcx.sess.span_err(attr.span, &msg); + } else { + codegen_fn_attrs.link_section = Some(val); + } + } + } else if attr.has_name(sym::link_name) { + codegen_fn_attrs.link_name = attr.value_str(); + } else if attr.has_name(sym::link_ordinal) { + link_ordinal_span = Some(attr.span); + if let ordinal @ Some(_) = check_link_ordinal(tcx, attr) { + codegen_fn_attrs.link_ordinal = ordinal; + } + } else if attr.has_name(sym::no_sanitize) { + no_sanitize_span = Some(attr.span); + if let Some(list) = attr.meta_item_list() { + for item in list.iter() { + if item.has_name(sym::address) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::ADDRESS; + } else if item.has_name(sym::cfi) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::CFI; + } else if item.has_name(sym::kcfi) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::KCFI; + } else if item.has_name(sym::memory) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMORY; + } else if item.has_name(sym::memtag) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::MEMTAG; + } else if item.has_name(sym::shadow_call_stack) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::SHADOWCALLSTACK; + } else if item.has_name(sym::thread) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::THREAD; + } else if item.has_name(sym::hwaddress) { + codegen_fn_attrs.no_sanitize |= SanitizerSet::HWADDRESS; + } else { + tcx.sess + .struct_span_err(item.span(), "invalid argument for `no_sanitize`") + .note("expected one of: `address`, `cfi`, `hwaddress`, `kcfi`, `memory`, `memtag`, `shadow-call-stack`, or `thread`") + .emit(); + } + } + } + } else if attr.has_name(sym::instruction_set) { + codegen_fn_attrs.instruction_set = match attr.meta_kind() { + Some(MetaItemKind::List(ref items)) => match items.as_slice() { + [NestedMetaItem::MetaItem(set)] => { + let segments = + set.path.segments.iter().map(|x| x.ident.name).collect::<Vec<_>>(); + match segments.as_slice() { + [sym::arm, sym::a32] | [sym::arm, sym::t32] => { + if !tcx.sess.target.has_thumb_interworking { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0779, + "target does not support `#[instruction_set]`" + ) + .emit(); + None + } else if segments[1] == sym::a32 { + Some(InstructionSetAttr::ArmA32) + } else if segments[1] == sym::t32 { + Some(InstructionSetAttr::ArmT32) + } else { + unreachable!() + } + } + _ => { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0779, + "invalid instruction set specified", + ) + .emit(); + None + } + } + } + [] => { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0778, + "`#[instruction_set]` requires an argument" + ) + .emit(); + None + } + _ => { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0779, + "cannot specify more than one instruction set" + ) + .emit(); + None + } + }, + _ => { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0778, + "must specify an instruction set" + ) + .emit(); + None + } + }; + } else if attr.has_name(sym::repr) { + codegen_fn_attrs.alignment = match attr.meta_item_list() { + Some(items) => match items.as_slice() { + [item] => match item.name_value_literal() { + Some((sym::align, literal)) => { + let alignment = rustc_attr::parse_alignment(&literal.kind); + + match alignment { + Ok(align) => Some(align), + Err(msg) => { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0589, + "invalid `repr(align)` attribute: {}", + msg + ) + .emit(); + + None + } + } + } + _ => None, + }, + [] => None, + _ => None, + }, + None => None, + }; + } + } + + codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| { + if !attr.has_name(sym::inline) { + return ia; + } + match attr.meta_kind() { + Some(MetaItemKind::Word) => InlineAttr::Hint, + Some(MetaItemKind::List(ref items)) => { + inline_span = Some(attr.span); + if items.len() != 1 { + struct_span_err!( + tcx.sess.diagnostic(), + attr.span, + E0534, + "expected one argument" + ) + .emit(); + InlineAttr::None + } else if list_contains_name(&items, sym::always) { + InlineAttr::Always + } else if list_contains_name(&items, sym::never) { + InlineAttr::Never + } else { + struct_span_err!( + tcx.sess.diagnostic(), + items[0].span(), + E0535, + "invalid argument" + ) + .help("valid inline arguments are `always` and `never`") + .emit(); + + InlineAttr::None + } + } + Some(MetaItemKind::NameValue(_)) => ia, + None => ia, + } + }); + + codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| { + if !attr.has_name(sym::optimize) { + return ia; + } + let err = |sp, s| struct_span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s).emit(); + match attr.meta_kind() { + Some(MetaItemKind::Word) => { + err(attr.span, "expected one argument"); + ia + } + Some(MetaItemKind::List(ref items)) => { + inline_span = Some(attr.span); + if items.len() != 1 { + err(attr.span, "expected one argument"); + OptimizeAttr::None + } else if list_contains_name(&items, sym::size) { + OptimizeAttr::Size + } else if list_contains_name(&items, sym::speed) { + OptimizeAttr::Speed + } else { + err(items[0].span(), "invalid argument"); + OptimizeAttr::None + } + } + Some(MetaItemKind::NameValue(_)) => ia, + None => ia, + } + }); + + // #73631: closures inherit `#[target_feature]` annotations + if tcx.features().target_feature_11 && tcx.is_closure(did.to_def_id()) { + let owner_id = tcx.parent(did.to_def_id()); + if tcx.def_kind(owner_id).has_codegen_attrs() { + codegen_fn_attrs + .target_features + .extend(tcx.codegen_fn_attrs(owner_id).target_features.iter().copied()); + } + } + + // If a function uses #[target_feature] it can't be inlined into general + // purpose functions as they wouldn't have the right target features + // enabled. For that reason we also forbid #[inline(always)] as it can't be + // respected. + if !codegen_fn_attrs.target_features.is_empty() { + if codegen_fn_attrs.inline == InlineAttr::Always { + if let Some(span) = inline_span { + tcx.sess.span_err( + span, + "cannot use `#[inline(always)]` with \ + `#[target_feature]`", + ); + } + } + } + + if !codegen_fn_attrs.no_sanitize.is_empty() { + if codegen_fn_attrs.inline == InlineAttr::Always { + if let (Some(no_sanitize_span), Some(inline_span)) = (no_sanitize_span, inline_span) { + let hir_id = tcx.hir().local_def_id_to_hir_id(did); + tcx.struct_span_lint_hir( + lint::builtin::INLINE_NO_SANITIZE, + hir_id, + no_sanitize_span, + "`no_sanitize` will have no effect after inlining", + |lint| lint.span_note(inline_span, "inlining requested here"), + ) + } + } + } + + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE; + codegen_fn_attrs.inline = InlineAttr::Never; + } + + // Weak lang items have the same semantics as "std internal" symbols in the + // sense that they're preserved through all our LTO passes and only + // strippable by the linker. + // + // Additionally weak lang items have predetermined symbol names. + if WEAK_LANG_ITEMS.iter().any(|&l| tcx.lang_items().get(l) == Some(did.to_def_id())) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; + } + if let Some((name, _)) = lang_items::extract(attrs) + && let Some(lang_item) = LangItem::from_name(name) + && let Some(link_name) = lang_item.link_name() + { + codegen_fn_attrs.export_name = Some(link_name); + codegen_fn_attrs.link_name = Some(link_name); + } + check_link_name_xor_ordinal(tcx, &codegen_fn_attrs, link_ordinal_span); + + // Internal symbols to the standard library all have no_mangle semantics in + // that they have defined symbol names present in the function name. This + // also applies to weak symbols where they all have known symbol names. + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL) { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_MANGLE; + } + + // Any linkage to LLVM intrinsics for now forcibly marks them all as never + // unwinds since LLVM sometimes can't handle codegen which `invoke`s + // intrinsic functions. + if let Some(name) = &codegen_fn_attrs.link_name { + if name.as_str().starts_with("llvm.") { + codegen_fn_attrs.flags |= CodegenFnAttrFlags::NEVER_UNWIND; + } + } + + codegen_fn_attrs +} + +/// Checks if the provided DefId is a method in a trait impl for a trait which has track_caller +/// applied to the method prototype. +fn should_inherit_track_caller(tcx: TyCtxt<'_>, def_id: DefId) -> bool { + if let Some(impl_item) = tcx.opt_associated_item(def_id) + && let ty::AssocItemContainer::ImplContainer = impl_item.container + && let Some(trait_item) = impl_item.trait_item_def_id + { + return tcx + .codegen_fn_attrs(trait_item) + .flags + .intersects(CodegenFnAttrFlags::TRACK_CALLER); + } + + false +} + +fn check_link_ordinal(tcx: TyCtxt<'_>, attr: &ast::Attribute) -> Option<u16> { + use rustc_ast::{LitIntType, LitKind, MetaItemLit}; + if !tcx.features().raw_dylib && tcx.sess.target.arch == "x86" { + feature_err( + &tcx.sess.parse_sess, + sym::raw_dylib, + attr.span, + "`#[link_ordinal]` is unstable on x86", + ) + .emit(); + } + let meta_item_list = attr.meta_item_list(); + let meta_item_list = meta_item_list.as_deref(); + let sole_meta_list = match meta_item_list { + Some([item]) => item.lit(), + Some(_) => { + tcx.sess + .struct_span_err(attr.span, "incorrect number of arguments to `#[link_ordinal]`") + .note("the attribute requires exactly one argument") + .emit(); + return None; + } + _ => None, + }; + if let Some(MetaItemLit { kind: LitKind::Int(ordinal, LitIntType::Unsuffixed), .. }) = + sole_meta_list + { + // According to the table at https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-header, + // the ordinal must fit into 16 bits. Similarly, the Ordinal field in COFFShortExport (defined + // in llvm/include/llvm/Object/COFFImportFile.h), which we use to communicate import information + // to LLVM for `#[link(kind = "raw-dylib"_])`, is also defined to be uint16_t. + // + // FIXME: should we allow an ordinal of 0? The MSVC toolchain has inconsistent support for this: + // both LINK.EXE and LIB.EXE signal errors and abort when given a .DEF file that specifies + // a zero ordinal. However, llvm-dlltool is perfectly happy to generate an import library + // for such a .DEF file, and MSVC's LINK.EXE is also perfectly happy to consume an import + // library produced by LLVM with an ordinal of 0, and it generates an .EXE. (I don't know yet + // if the resulting EXE runs, as I haven't yet built the necessary DLL -- see earlier comment + // about LINK.EXE failing.) + if *ordinal <= u16::MAX as u128 { + Some(*ordinal as u16) + } else { + let msg = format!("ordinal value in `link_ordinal` is too large: `{}`", &ordinal); + tcx.sess + .struct_span_err(attr.span, &msg) + .note("the value may not exceed `u16::MAX`") + .emit(); + None + } + } else { + tcx.sess + .struct_span_err(attr.span, "illegal ordinal format in `link_ordinal`") + .note("an unsuffixed integer value, e.g., `1`, is expected") + .emit(); + None + } +} + +fn check_link_name_xor_ordinal( + tcx: TyCtxt<'_>, + codegen_fn_attrs: &CodegenFnAttrs, + inline_span: Option<Span>, +) { + if codegen_fn_attrs.link_name.is_none() || codegen_fn_attrs.link_ordinal.is_none() { + return; + } + let msg = "cannot use `#[link_name]` with `#[link_ordinal]`"; + if let Some(span) = inline_span { + tcx.sess.span_err(span, msg); + } else { + tcx.sess.err(msg); + } +} + +pub fn provide(providers: &mut Providers) { + *providers = Providers { codegen_fn_attrs, should_inherit_track_caller, ..*providers }; +} |