mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Auto merge of #104799 - pcc:linkage-fn, r=tmiasko

Browse Source 
Support Option and similar enums as type of static variable with linkage attribute

Compiler MCP:
rust-lang/compiler-team#565
This commit is contained in:
bors 2022-12-07 10:24:59 +00:00
commit 91b8f34ac2
22 changed files with 157 additions and 89 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
compiler/rustc_codegen_gcc/src/consts.rs
View File

@ -8,13 +8,11 @@
use rustc_middle::ty::{self, Instance, Ty};
use rustc_middle::ty::layout::LayoutOf;
use rustc_middle::mir::interpret::{self, ConstAllocation, ErrorHandled, Scalar as InterpScalar, read_target_uint};
use rustc_span::Span;
use rustc_span::def_id::DefId;
use rustc_target::abi::{self, Align, HasDataLayout, Primitive, Size, WrappingRange};
use crate::base;
use crate::context::CodegenCx;
use crate::errors::LinkageConstOrMutType;
use crate::type_of::LayoutGccExt;
impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
@ -239,12 +237,12 @@ pub fn get_static(&self, def_id: DefId) -> LValue<'gcc> {
}
Node::ForeignItem(&hir::ForeignItem {
span,
span: _,
kind: hir::ForeignItemKind::Static(..),
..
}) => {
let fn_attrs = self.tcx.codegen_fn_attrs(def_id);
check_and_apply_linkage(&self, &fn_attrs, ty, sym, span)
check_and_apply_linkage(&self, &fn_attrs, ty, sym)
}
item => bug!("get_static: expected static, found {:?}", item),
@ -257,8 +255,7 @@ pub fn get_static(&self, def_id: DefId) -> LValue<'gcc> {
//debug!("get_static: sym={} item_attr={:?}", sym, self.tcx.item_attrs(def_id));
let attrs = self.tcx.codegen_fn_attrs(def_id);
let span = self.tcx.def_span(def_id);
let global = check_and_apply_linkage(&self, &attrs, ty, sym, span);
let global = check_and_apply_linkage(&self, &attrs, ty, sym);
let needs_dll_storage_attr = false; // TODO(antoyo)
@ -355,24 +352,12 @@ pub fn codegen_static_initializer<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, def_id
Ok((const_alloc_to_gcc(cx, alloc), alloc))
}
fn check_and_apply_linkage<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, attrs: &CodegenFnAttrs, ty: Ty<'tcx>, sym: &str, span: Span) -> LValue<'gcc> {
fn check_and_apply_linkage<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, attrs: &CodegenFnAttrs, ty: Ty<'tcx>, sym: &str) -> LValue<'gcc> {
let is_tls = attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL);
let llty = cx.layout_of(ty).gcc_type(cx, true);
if let Some(linkage) = attrs.linkage {
// If this is a static with a linkage specified, then we need to handle
// it a little specially. The typesystem prevents things like &T and
// extern "C" fn() from being non-null, so we can't just declare a
// static and call it a day. Some linkages (like weak) will make it such
// that the static actually has a null value.
let llty2 =
if let ty::RawPtr(ref mt) = ty.kind() {
cx.layout_of(mt.ty).gcc_type(cx, true)
}
else {
cx.sess().emit_fatal(LinkageConstOrMutType { span: span })
};
if let Some(linkage) = attrs.import_linkage {
// Declare a symbol `foo` with the desired linkage.
let global1 = cx.declare_global_with_linkage(&sym, llty2, base::global_linkage_to_gcc(linkage));
let global1 = cx.declare_global_with_linkage(&sym, cx.type_i8(), base::global_linkage_to_gcc(linkage));
// Declare an internal global `extern_with_linkage_foo` which
// is initialized with the address of `foo`. If `foo` is

7
compiler/rustc_codegen_gcc/src/errors.rs
View File

@ -211,13 +211,6 @@ pub(crate) struct InvalidMonomorphizationUnsupportedOperation<'a> {
pub in_elem: Ty<'a>,
}
#[derive(Diagnostic)]
#[diag(codegen_gcc_linkage_const_or_mut_type)]
pub(crate) struct LinkageConstOrMutType {
#[primary_span]
pub span: Span,
}
#[derive(Diagnostic)]
#[diag(codegen_gcc_lto_not_supported)]
pub(crate) struct LTONotSupported;

18
compiler/rustc_codegen_llvm/src/consts.rs
View File

@ -1,7 +1,7 @@
use crate::base;
use crate::common::{self, CodegenCx};
use crate::debuginfo;
use crate::errors::{InvalidMinimumAlignment, LinkageConstOrMutType, SymbolAlreadyDefined};
use crate::errors::{InvalidMinimumAlignment, SymbolAlreadyDefined};
use crate::llvm::{self, True};
use crate::llvm_util;
use crate::type_::Type;
@ -162,22 +162,12 @@ fn check_and_apply_linkage<'ll, 'tcx>(
def_id: DefId,
) -> &'ll Value {
let llty = cx.layout_of(ty).llvm_type(cx);
if let Some(linkage) = attrs.linkage {
if let Some(linkage) = attrs.import_linkage {
debug!("get_static: sym={} linkage={:?}", sym, linkage);
// If this is a static with a linkage specified, then we need to handle
// it a little specially. The typesystem prevents things like &T and
// extern "C" fn() from being non-null, so we can't just declare a
// static and call it a day. Some linkages (like weak) will make it such
// that the static actually has a null value.
let llty2 = if let ty::RawPtr(ref mt) = ty.kind() {
cx.layout_of(mt.ty).llvm_type(cx)
} else {
cx.sess().emit_fatal(LinkageConstOrMutType { span: cx.tcx.def_span(def_id) })
};
unsafe {
// Declare a symbol `foo` with the desired linkage.
let g1 = cx.declare_global(sym, llty2);
let g1 = cx.declare_global(sym, cx.type_i8());
llvm::LLVMRustSetLinkage(g1, base::linkage_to_llvm(linkage));
// Declare an internal global `extern_with_linkage_foo` which
@ -195,7 +185,7 @@ fn check_and_apply_linkage<'ll, 'tcx>(
})
});
llvm::LLVMRustSetLinkage(g2, llvm::Linkage::InternalLinkage);
llvm::LLVMSetInitializer(g2, g1);
llvm::LLVMSetInitializer(g2, cx.const_ptrcast(g1, llty));
g2
}
} else if cx.tcx.sess.target.arch == "x86" &&

7
compiler/rustc_codegen_llvm/src/errors.rs
View File

@ -61,13 +61,6 @@ pub(crate) struct InvalidMinimumAlignment {
pub err: String,
}
#[derive(Diagnostic)]
#[diag(codegen_llvm_linkage_const_or_mut_type)]
pub(crate) struct LinkageConstOrMutType {
#[primary_span]
pub span: Span,
}
#[derive(Diagnostic)]
#[diag(codegen_llvm_sanitizer_memtag_requires_mte)]
pub(crate) struct SanitizerMemtagRequiresMte;

1
compiler/rustc_error_codes/src/error_codes.rs
View File

@ -494,6 +494,7 @@
E0787: include_str!("./error_codes/E0787.md"),
E0788: include_str!("./error_codes/E0788.md"),
E0790: include_str!("./error_codes/E0790.md"),
E0791: include_str!("./error_codes/E0791.md"),
;
// E0006, // merged with E0005
// E0008, // cannot bind by-move into a pattern guard

41
compiler/rustc_error_codes/src/error_codes/E0791.md Normal file
View File

@ -0,0 +1,41 @@
Static variables with the `#[linkage]` attribute within external blocks
must have one of the following types, which are equivalent to a nullable
pointer in C:
* `*mut T` or `*const T`, where `T` may be any type.
* An enumerator type with no `#[repr]` attribute and with two variants, where
one of the variants has no fields, and the other has a single field of one of
the following non-nullable types:
* Reference type
* Function pointer type
The variants can appear in either order.
For example, the following declaration is invalid:
```compile_fail,E0791
#![feature(linkage)]
extern "C" {
#[linkage = "extern_weak"]
static foo: i8;
}
```
The following declarations are valid:
```
#![feature(linkage)]
extern "C" {
#[linkage = "extern_weak"]
static foo: Option<unsafe extern "C" fn()>;
#[linkage = "extern_weak"]
static bar: Option<&'static i8>;
#[linkage = "extern_weak"]
static baz: *mut i8;
}
```

3
compiler/rustc_error_messages/locales/en-US/codegen_gcc.ftl
View File

@ -1,6 +1,3 @@
codegen_gcc_linkage_const_or_mut_type =
must have type `*const T` or `*mut T` due to `#[linkage]` attribute
codegen_gcc_unwinding_inline_asm =
GCC backend does not support unwinding from inline asm

3
compiler/rustc_error_messages/locales/en-US/codegen_llvm.ftl
View File

@ -23,9 +23,6 @@ codegen_llvm_branch_protection_requires_aarch64 =
codegen_llvm_invalid_minimum_alignment =
invalid minimum global alignment: {$err}
codegen_llvm_linkage_const_or_mut_type =
must have type `*const T` or `*mut T` due to `#[linkage]` attribute
codegen_llvm_sanitizer_memtag_requires_mte =
`-Zsanitizer=memtag` requires `-Ctarget-feature=+mte`

3
compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl
View File

@ -115,3 +115,6 @@ hir_analysis_const_bound_for_non_const_trait =
hir_analysis_self_in_impl_self =
`Self` is not valid in the self type of an impl block
.note = replace `Self` with a different type
hir_analysis_linkage_type =
invalid type for variable with `#[linkage]` attribute

35
compiler/rustc_hir_analysis/src/check/check.rs
View File

@ -1,4 +1,5 @@
use crate::check::intrinsicck::InlineAsmCtxt;
use crate::errors::LinkageType;
use super::compare_method::check_type_bounds;
use super::compare_method::{compare_impl_method, compare_ty_impl};
@ -20,7 +21,7 @@
use rustc_middle::ty::layout::{LayoutError, MAX_SIMD_LANES};
use rustc_middle::ty::subst::GenericArgKind;
use rustc_middle::ty::util::{Discr, IntTypeExt};
use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable};
use rustc_middle::ty::{self, AdtDef, ParamEnv, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable};
use rustc_session::lint::builtin::{UNINHABITED_STATIC, UNSUPPORTED_CALLING_CONVENTIONS};
use rustc_span::symbol::sym;
use rustc_span::{self, Span};
@ -478,6 +479,36 @@ fn check_opaque_meets_bounds<'tcx>(
let _ = infcx.inner.borrow_mut().opaque_type_storage.take_opaque_types();
}
fn is_enum_of_nonnullable_ptr<'tcx>(
tcx: TyCtxt<'tcx>,
adt_def: AdtDef<'tcx>,
substs: SubstsRef<'tcx>,
) -> bool {
if adt_def.repr().inhibit_enum_layout_opt() {
return false;
}
let [var_one, var_two] = &adt_def.variants().raw[..] else {
return false;
};
let (([], [field]) | ([field], [])) = (&var_one.fields[..], &var_two.fields[..]) else {
return false;
};
matches!(field.ty(tcx, substs).kind(), ty::FnPtr(..) | ty::Ref(..))
}
fn check_static_linkage<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) {
if tcx.codegen_fn_attrs(def_id).import_linkage.is_some() {
if match tcx.type_of(def_id).kind() {
ty::RawPtr(_) => false,
ty::Adt(adt_def, substs) => !is_enum_of_nonnullable_ptr(tcx, *adt_def, *substs),
_ => true,
} {
tcx.sess.emit_err(LinkageType { span: tcx.def_span(def_id) });
}
}
}
fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
debug!(
"check_item_type(it.def_id={:?}, it.name={})",
@ -490,6 +521,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
tcx.ensure().typeck(id.owner_id.def_id);
maybe_check_static_with_link_section(tcx, id.owner_id.def_id);
check_static_inhabited(tcx, id.owner_id.def_id);
check_static_linkage(tcx, id.owner_id.def_id);
}
DefKind::Const => {
tcx.ensure().typeck(id.owner_id.def_id);
@ -627,6 +659,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
}
hir::ForeignItemKind::Static(..) => {
check_static_inhabited(tcx, def_id);
check_static_linkage(tcx, def_id);
}
_ => {}
}

7
compiler/rustc_hir_analysis/src/collect.rs
View File

@ -1814,7 +1814,12 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
);
} else if attr.has_name(sym::linkage) {
if let Some(val) = attr.value_str() {
codegen_fn_attrs.linkage = Some(linkage_by_name(tcx, did, val.as_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() {

7
compiler/rustc_hir_analysis/src/errors.rs
View File

@ -289,3 +289,10 @@ pub struct SelfInImplSelf {
#[note]
pub note: (),
}
#[derive(Diagnostic)]
#[diag(hir_analysis_linkage_type, code = "E0791")]
pub(crate) struct LinkageType {
#[primary_span]
pub span: Span,
}

5
compiler/rustc_middle/src/middle/codegen_fn_attrs.rs
View File

@ -26,8 +26,10 @@ pub struct CodegenFnAttrs {
/// The `#[target_feature(enable = "...")]` attribute and the enabled
/// features (only enabled features are supported right now).
pub target_features: Vec<Symbol>,
/// The `#[linkage = "..."]` attribute and the value we found.
/// The `#[linkage = "..."]` attribute on Rust-defined items and the value we found.
pub linkage: Option<Linkage>,
/// The `#[linkage = "..."]` attribute on foreign items and the value we found.
pub import_linkage: Option<Linkage>,
/// The `#[link_section = "..."]` attribute, or what executable section this
/// should be placed in.
pub link_section: Option<Symbol>,
@ -113,6 +115,7 @@ pub const fn new() -> CodegenFnAttrs {
link_ordinal: None,
target_features: vec![],
linkage: None,
import_linkage: None,
link_section: None,
no_sanitize: SanitizerSet::empty(),
instruction_set: None,

37
library/std/src/sys/unix/weak.rs
View File

@ -29,7 +29,21 @@
use crate::sync::atomic::{self, AtomicPtr, Ordering};
// We can use true weak linkage on ELF targets.
#[cfg(not(any(target_os = "macos", target_os = "ios")))]
#[cfg(all(not(any(target_os = "macos", target_os = "ios")), not(bootstrap)))]
pub(crate) macro weak {
(fn $name:ident($($t:ty),*) -> $ret:ty) => (
let ref $name: ExternWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
extern "C" {
#[linkage = "extern_weak"]
static $name: Option<unsafe extern "C" fn($($t),*) -> $ret>;
}
#[allow(unused_unsafe)]
ExternWeak::new(unsafe { $name })
};
)
}
#[cfg(all(not(any(target_os = "macos", target_os = "ios")), bootstrap))]
pub(crate) macro weak {
(fn $name:ident($($t:ty),*) -> $ret:ty) => (
let ref $name: ExternWeak<unsafe extern "C" fn($($t),*) -> $ret> = {
@ -47,11 +61,31 @@
#[cfg(any(target_os = "macos", target_os = "ios"))]
pub(crate) use self::dlsym as weak;
#[cfg(not(bootstrap))]
pub(crate) struct ExternWeak<F: Copy> {
weak_ptr: Option<F>,
}
#[cfg(not(bootstrap))]
impl<F: Copy> ExternWeak<F> {
#[inline]
pub(crate) fn new(weak_ptr: Option<F>) -> Self {
ExternWeak { weak_ptr }
}
#[inline]
pub(crate) fn get(&self) -> Option<F> {
self.weak_ptr
}
}
#[cfg(bootstrap)]
pub(crate) struct ExternWeak<F> {
weak_ptr: *const libc::c_void,
_marker: PhantomData<F>,
}
#[cfg(bootstrap)]
impl<F> ExternWeak<F> {
#[inline]
pub(crate) fn new(weak_ptr: *const libc::c_void) -> Self {
@ -59,6 +93,7 @@ pub(crate) fn new(weak_ptr: *const libc::c_void) -> Self {
}
}
#[cfg(bootstrap)]
impl<F> ExternWeak<F> {
#[inline]
pub(crate) fn get(&self) -> Option<F> {

2
src/test/ui/feature-gates/feature-gate-linkage.rs
View File

@ -1,5 +1,5 @@
extern "C" {
#[linkage = "extern_weak"] static foo: isize;
#[linkage = "extern_weak"] static foo: *mut isize;
//~^ ERROR: the `linkage` attribute is experimental and not portable
}

2
src/test/ui/feature-gates/feature-gate-linkage.stderr
View File

@ -1,7 +1,7 @@
error[E0658]: the `linkage` attribute is experimental and not portable across platforms
--> $DIR/feature-gate-linkage.rs:2:5
|
LL | #[linkage = "extern_weak"] static foo: isize;
LL | #[linkage = "extern_weak"] static foo: *mut isize;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #29603 <https://github.com/rust-lang/rust/issues/29603> for more information

0
src/test/ui/linkage-attr/auxiliary/def_illtyped_external.rs → src/test/ui/linkage-attr/auxiliary/def_external.rs
View File

8
src/test/ui/linkage-attr/linkage-import.rs Normal file
View File

@ -0,0 +1,8 @@
// build-pass
// aux-build:def_external.rs
extern crate def_external as dep;
fn main() {
println!("{:p}", &dep::EXTERN);
}

11
src/test/ui/linkage-attr/linkage-requires-raw-ptr.rs
View File

@ -1,11 +0,0 @@
// rust-lang/rust#59548: We used to ICE when trying to use a static
// with a type that violated its own `#[linkage]`.
// build-fail
// aux-build:def_illtyped_external.rs
extern crate def_illtyped_external as dep;
fn main() {
println!("{:p}", &dep::EXTERN);
}

8
src/test/ui/linkage-attr/linkage-requires-raw-ptr.stderr
View File

@ -1,8 +0,0 @@
error: must have type `*const T` or `*mut T` due to `#[linkage]` attribute
--> $DIR/auxiliary/def_illtyped_external.rs:5:1
|
LL | pub static EXTERN: u32 = 0;
| ^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error

9
src/test/ui/linkage-attr/linkage2.rs
View File

@ -1,16 +1,11 @@
// FIXME https://github.com/rust-lang/rust/issues/59774
// build-fail
// normalize-stderr-test "thread.*panicked.*Metadata module not compiled.*\n" -> ""
// normalize-stderr-test "note:.*RUST_BACKTRACE=1.*\n" -> ""
// ignore-sgx no weak linkages permitted
// check-fail
#![feature(linkage)]
extern "C" {
#[linkage = "extern_weak"]
static foo: i32;
//~^ ERROR: must have type `*const T` or `*mut T` due to `#[linkage]` attribute
//~^ ERROR: invalid type for variable with `#[linkage]` attribute
}
fn main() {

5
src/test/ui/linkage-attr/linkage2.stderr
View File

@ -1,8 +1,9 @@
error: must have type `*const T` or `*mut T` due to `#[linkage]` attribute
--> $DIR/linkage2.rs:12:5
error[E0791]: invalid type for variable with `#[linkage]` attribute
--> $DIR/linkage2.rs:7:5
|
LL | static foo: i32;
| ^^^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0791`.