Rollup merge of #155065 - folkertdev:macho-section-specifier, r=JonathanBrouwer

Error on invalid macho section specifier

The macho section specifier used by `#[link_section = "..."]` is more strict than e.g. the one for elf. LLVM will error when you get it wrong, which is easy to do if you're used to elf. So, provide some guidance for the simplest mistakes, based on the LLVM validation.

Currently compilation fails with an LLVM error, see https://godbolt.org/z/WoE8EdK1K.

The LLVM validation logic is at

https://github.com/llvm/llvm-project/blob/a0f0d6342e0cd75b7f41e0e6aae0944393b68a62/llvm/lib/MC/MCSectionMachO.cpp#L199-L203

LLVM validates the other components of the section specifier too, but it feels a bit fragile to duplicate those checks. If you get that far, hopefully the LLVM errors will be sufficient to get unstuck.

---

sidequest from https://github.com/rust-lang/rust/pull/147811

r? JonathanBrouwer

specifically, is this the right place for this sort of validation? `rustc_attr_parsing` also does some validation.

compiler/rustc_attr_parsing/src/attributes/link_attrs.rs

@@ -16,8 +16,9 @@
 use crate::session_diagnostics::{
     AsNeededCompatibility, BundleNeedsStatic, EmptyLinkName, ExportSymbolsNeedsStatic,
     ImportNameTypeRaw, ImportNameTypeX86, IncompatibleWasmLink, InvalidLinkModifier,
-    LinkFrameworkApple, LinkOrdinalOutOfRange, LinkRequiresName, MultipleModifiers,
-    NullOnLinkSection, RawDylibNoNul, RawDylibOnlyWindows, WholeArchiveNeedsStatic,
+    InvalidMachoSection, InvalidMachoSectionReason, LinkFrameworkApple, LinkOrdinalOutOfRange,
+    LinkRequiresName, MultipleModifiers, NullOnLinkSection, RawDylibNoNul, RawDylibOnlyWindows,
+    WholeArchiveNeedsStatic,
 };
 
 pub(crate) struct LinkNameParser;
@@ -462,6 +463,29 @@ fn parse_link_import_name_type<S: Stage>(
 
 pub(crate) struct LinkSectionParser;
 
+fn check_link_section_macho(name: Symbol) -> Result<(), InvalidMachoSectionReason> {
+    let mut parts = name.as_str().split(',').map(|s| s.trim());
+
+    // The segment can be empty.
+    let _segment = parts.next();
+
+    // But the section is required.
+    let section = match parts.next() {
+        None | Some("") => return Err(InvalidMachoSectionReason::MissingSection),
+        Some(section) => section,
+    };
+
+    if section.len() > 16 {
+        return Err(InvalidMachoSectionReason::SectionTooLong { section: section.to_string() });
+    }
+
+    // LLVM also checks the other components of the section specifier, but that logic is hard to
+    // keep in sync. We skip it here for now, assuming that if you got that far you'll be able
+    // to interpret the LLVM errors.
+
+    Ok(())
+}
+
 impl<S: Stage> SingleAttributeParser<S> for LinkSectionParser {
     const PATH: &[Symbol] = &[sym::link_section];
     const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
@@ -495,6 +519,18 @@ fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser) -> Option<Attrib
             return None;
         }
 
+        // We (currently) only validate macho section specifiers.
+        match cx.sess.target.binary_format {
+            BinaryFormat::MachO => match check_link_section_macho(name) {
+                Ok(()) => {}
+                Err(reason) => {
+                    cx.emit_err(InvalidMachoSection { name_span: nv.value_span, reason });
+                    return None;
+                }
+            },
+            BinaryFormat::Coff | BinaryFormat::Elf | BinaryFormat::Wasm | BinaryFormat::Xcoff => {}
+        }
+
         Some(LinkSection { name, span: cx.attr_span })
     }
 }

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -1137,3 +1137,22 @@ pub(crate) struct UnstableAttrForAlreadyStableFeature {
     #[label("the stability attribute annotates this item")]
     pub item_span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag("invalid Mach-O section specifier")]
+pub(crate) struct InvalidMachoSection {
+    #[primary_span]
+    #[label("not a valid Mach-O section specifier")]
+    pub name_span: Span,
+    #[subdiagnostic]
+    pub reason: InvalidMachoSectionReason,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum InvalidMachoSectionReason {
+    #[note("a Mach-O section specifier requires a segment and a section, separated by a comma")]
+    #[help("an example of a valid Mach-O section specifier is `__TEXT,__cstring`")]
+    MissingSection,
+    #[note("section name `{$section}` is longer than 16 bytes")]
+    SectionTooLong { section: String },
+}

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -1098,8 +1098,8 @@ pub enum AttributeKind {
 
     /// Represents [`#[link_section]`](https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute)
     LinkSection {
-        name: Symbol,
         span: Span,
+        name: Symbol,
     },
 
     /// Represents `#[linkage]`.

tests/codegen-llvm/link_section.rs

@@ -3,14 +3,14 @@
 
 #![crate_type = "lib"]
 
-// CHECK: @VAR1 = {{(dso_local )?}}constant [4 x i8] c"\01\00\00\00", section ".test_one"
+// CHECK: @VAR1 = {{(dso_local )?}}constant [4 x i8] c"\01\00\00\00", section "__TEST,one"
 #[no_mangle]
-#[link_section = ".test_one"]
+#[link_section = "__TEST,one"]
 #[cfg(target_endian = "little")]
 pub static VAR1: u32 = 1;
 
 #[no_mangle]
-#[link_section = ".test_one"]
+#[link_section = "__TEST,one"]
 #[cfg(target_endian = "big")]
 pub static VAR1: u32 = 0x01000000;
 
@@ -19,17 +19,17 @@ pub enum E {
     B(f32),
 }
 
-// CHECK: @VAR2 = {{(dso_local )?}}constant {{.*}}, section ".test_two"
+// CHECK: @VAR2 = {{(dso_local )?}}constant {{.*}}, section "__TEST,two"
 #[no_mangle]
-#[link_section = ".test_two"]
+#[link_section = "__TEST,two"]
 pub static VAR2: E = E::A(666);
 
-// CHECK: @VAR3 = {{(dso_local )?}}constant {{.*}}, section ".test_three"
+// CHECK: @VAR3 = {{(dso_local )?}}constant {{.*}}, section "__TEST,three"
 #[no_mangle]
-#[link_section = ".test_three"]
+#[link_section = "__TEST,three"]
 pub static VAR3: E = E::B(1.);
 
-// CHECK: define {{(dso_local )?}}void @fn1() {{.*}} section ".test_four" {
+// CHECK: define {{(dso_local )?}}void @fn1() {{.*}} section "__TEST,four" {
 #[no_mangle]
-#[link_section = ".test_four"]
+#[link_section = "__TEST,four"]
 pub fn fn1() {}

tests/codegen-llvm/naked-fn/naked-functions.rs

@@ -22,7 +22,7 @@
 //@[thumb] needs-llvm-components: arm
 
 #![crate_type = "lib"]
-#![feature(no_core, lang_items, rustc_attrs)]
+#![feature(no_core, lang_items, rustc_attrs, cfg_target_object_format)]
 #![no_core]
 
 extern crate minicore;
@@ -170,14 +170,17 @@ pub extern "C" fn naked_with_args_and_return(a: isize, b: isize) -> isize {
 }
 
 // linux,linux_no_function_sections: .pushsection .text.some_different_name,\22ax\22, @progbits
-// macos:            .pushsection .text.some_different_name,regular,pure_instructions
+// macos: .pushsection __TEXT,different,regular,pure_instructions
 // win_x86_msvc,win_x86_gnu,win_i686_gnu: .section .text.some_different_name,\22xr\22
 // win_x86_gnu_function_sections: .section .text.some_different_name,\22xr\22
 // thumb:            .pushsection .text.some_different_name,\22ax\22, %progbits
 // CHECK-LABEL: test_link_section:
 #[no_mangle]
 #[unsafe(naked)]
-#[link_section = ".text.some_different_name"]
+#[link_section = cfg_select!(
+    target_object_format = "mach-o" =>  "__TEXT,different",
+    _ => ".text.some_different_name"
+)]
 pub extern "C" fn test_link_section() {
     cfg_select! {
         all(target_arch = "arm", target_feature = "thumb-mode") => {

tests/rustdoc-html/attributes-2021-edition.rs

@@ -9,6 +9,6 @@ pub extern "C" fn f() {}
 #[export_name = "bar"]
 pub extern "C" fn g() {}
 
-//@ has foo/fn.example.html '//pre[@class="rust item-decl"]' '#[unsafe(link_section = ".text")]'
-#[link_section = ".text"]
+//@ has foo/fn.example.html '//pre[@class="rust item-decl"]' '#[unsafe(link_section = "__TEXT,__text")]'
+#[link_section = "__TEXT,__text"]
 pub extern "C" fn example() {}

tests/rustdoc-html/attributes.rs

@@ -1,4 +1,5 @@
 //@ edition: 2024
+//@ only-linux
 #![crate_name = "foo"]
 
 //@ has foo/fn.f.html '//*[@class="code-attribute"]' '#[unsafe(no_mangle)]'

tests/rustdoc-html/inline_cross/attributes.rs

@@ -9,7 +9,7 @@
 pub use attributes::no_mangle;
 
 //@ has 'user/fn.link_section.html' '//pre[@class="rust item-decl"]' \
-//                                  '#[unsafe(link_section = ".here")]'
+//                                  '#[unsafe(link_section = "__TEXT,__here")]'
 pub use attributes::link_section;
 
 //@ has 'user/fn.export_name.html' '//pre[@class="rust item-decl"]' \

tests/rustdoc-html/inline_cross/auxiliary/attributes.rs

@@ -1,7 +1,7 @@
 #[unsafe(no_mangle)]
 pub fn no_mangle() {}
 
-#[unsafe(link_section = ".here")]
+#[unsafe(link_section = "__TEXT,__here")]
 pub fn link_section() {}
 
 #[unsafe(export_name = "exonym")]

tests/rustdoc-json/attrs/link_section_2021.rs

@@ -2,6 +2,6 @@
 #![no_std]
 
 //@ count "$.index[?(@.name=='example')].attrs[*]" 1
-//@ is "$.index[?(@.name=='example')].attrs[*].link_section" '".text"'
-#[link_section = ".text"]
+//@ is "$.index[?(@.name=='example')].attrs[*].link_section" '"__TEXT,__text"'
+#[link_section = "__TEXT,__text"]
 pub extern "C" fn example() {}

tests/rustdoc-json/attrs/link_section_2024.rs

@@ -5,6 +5,6 @@
 // However, the unsafe qualification is not shown by rustdoc.
 
 //@ count "$.index[?(@.name=='example')].attrs[*]" 1
-//@ is "$.index[?(@.name=='example')].attrs[*].link_section" '".text"'
-#[unsafe(link_section = ".text")]
+//@ is "$.index[?(@.name=='example')].attrs[*].link_section" '"__TEXT,__text"'
+#[unsafe(link_section = "__TEXT,__text")]
 pub extern "C" fn example() {}

tests/ui/asm/naked-functions.rs

@@ -3,7 +3,7 @@
 //@ ignore-spirv
 //@ reference: attributes.codegen.naked.body
 
-#![feature(asm_unwind, linkage, rustc_attrs)]
+#![feature(asm_unwind, linkage, rustc_attrs, cfg_target_object_format)]
 #![crate_type = "lib"]
 
 use std::arch::{asm, naked_asm};
@@ -200,7 +200,10 @@ pub extern "C" fn compatible_must_use_attributes() -> u64 {
 }
 
 #[export_name = "exported_function_name"]
-#[link_section = ".custom_section"]
+#[link_section = cfg_select!(
+    target_object_format = "mach-o" =>  "__TEXT,__custom",
+    _ => ".custom",
+)]
 #[unsafe(naked)]
 pub extern "C" fn compatible_ffi_attributes_1() {
     naked_asm!("", options(raw));

tests/ui/attributes/attr-on-mac-call.rs

@@ -27,7 +27,7 @@ fn main() {
     #[link_name = "x"]
     //~^ WARN attribute cannot be used on macro calls
     //~| WARN previously accepted
-    #[link_section = "x"]
+    #[link_section = "__TEXT,__text"]
     //~^ WARN attribute cannot be used on macro calls
     //~| WARN previously accepted
     #[link_ordinal(42)]

tests/ui/attributes/attr-on-mac-call.stderr

@@ -78,8 +78,8 @@ LL |     #[link_name = "x"]
 warning: `#[link_section]` attribute cannot be used on macro calls
   --> $DIR/attr-on-mac-call.rs:30:5
    |
-LL |     #[link_section = "x"]
-   |     ^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = "__TEXT,__text"]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics

tests/ui/attributes/codegen_attr_on_required_trait_method.rs

@@ -7,7 +7,7 @@ trait Test {
     //~^ ERROR cannot be used on required trait methods [unused_attributes]
     //~| WARN previously accepted
     fn method1(&self);
-    #[link_section = ".text"]
+    #[link_section = "__TEXT,__text"]
     //~^ ERROR cannot be used on required trait methods [unused_attributes]
     //~| WARN previously accepted
     fn method2(&self);

tests/ui/attributes/codegen_attr_on_required_trait_method.stderr

@@ -15,8 +15,8 @@ LL | #![deny(unused_attributes)]
 error: `#[link_section]` attribute cannot be used on required trait methods
   --> $DIR/codegen_attr_on_required_trait_method.rs:10:5
    |
-LL |     #[link_section = ".text"]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = "__TEXT,__text"]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions, inherent methods, provided trait methods, statics, and trait methods in impl blocks

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -74,7 +74,7 @@
 //~| WARN previously accepted
 //~| HELP can be applied to
 //~| HELP remove the attribute
-#![link_section = "1800"]
+#![link_section = ",1800"]
 //~^ WARN attribute cannot be used on
 //~| WARN previously accepted
 //~| HELP can be applied to
@@ -616,66 +616,66 @@ mod inner { #![link_name="1900"] }
     //~| HELP remove the attribute
 }
 
-#[link_section = "1800"]
+#[link_section = ",1800"]
 //~^ WARN attribute cannot be used on
 //~| WARN previously accepted
 //~| HELP can be applied to
 //~| HELP remove the attribute
 mod link_section {
-    mod inner { #![link_section="1800"] }
+    mod inner { #![link_section=",1800"] }
     //~^ WARN attribute cannot be used on
     //~| WARN previously accepted
     //~| HELP can be applied to
     //~| HELP remove the attribute
 
-    #[link_section = "1800"] fn f() { }
+    #[link_section = ",1800"] fn f() { }
 
-    #[link_section = "1800"] struct S;
+    #[link_section = ",1800"] struct S;
     //~^ WARN attribute cannot be used on
     //~| WARN previously accepted
     //~| HELP can be applied to
     //~| HELP remove the attribute
 
-    #[link_section = "1800"] type T = S;
+    #[link_section = ",1800"] type T = S;
     //~^ WARN attribute cannot be used on
     //~| WARN previously accepted
     //~| HELP can be applied to
     //~| HELP remove the attribute
 
-    #[link_section = "1800"] impl S { }
+    #[link_section = ",1800"] impl S { }
     //~^ WARN attribute cannot be used on
     //~| WARN previously accepted
     //~| HELP can be applied to
     //~| HELP remove the attribute
 
-    #[link_section = "1800"]
+    #[link_section = ",1800"]
     //~^ WARN attribute cannot be used on
     //~| WARN previously accepted
     //~| HELP can be applied to
     //~| HELP remove the attribute
     trait Tr {
-        #[link_section = "1800"]
+        #[link_section = ",1800"]
         //~^ WARN attribute cannot be used on
         //~| WARN previously accepted
         //~| HELP can be applied to
         //~| HELP remove the attribute
         fn inside_tr_no_default(&self);
 
-        #[link_section = "1800"]
+        #[link_section = ",1800"]
         fn inside_tr_default(&self) { }
     }
 
     impl S {
-        #[link_section = "1800"]
+        #[link_section = ",1800"]
         fn inside_abc_123(&self) { }
     }
 
     impl Tr for S {
-        #[link_section = "1800"]
+        #[link_section = ",1800"]
         fn inside_tr_no_default(&self) { }
     }
 
-    #[link_section = "1800"]
+    #[link_section = ",1800"]
     fn should_always_link() { }
 }
 

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -866,8 +866,8 @@ LL |     #[link_name = "1900"] impl S { }
 warning: `#[link_section]` attribute cannot be used on modules
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:619:1
    |
-LL | #[link_section = "1800"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[link_section = ",1800"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -875,8 +875,8 @@ LL | #[link_section = "1800"]
 warning: `#[link_section]` attribute cannot be used on modules
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:625:17
    |
-LL |     mod inner { #![link_section="1800"] }
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^
+LL |     mod inner { #![link_section=",1800"] }
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -884,8 +884,8 @@ LL |     mod inner { #![link_section="1800"] }
 warning: `#[link_section]` attribute cannot be used on structs
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:633:5
    |
-LL |     #[link_section = "1800"] struct S;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = ",1800"] struct S;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -893,8 +893,8 @@ LL |     #[link_section = "1800"] struct S;
 warning: `#[link_section]` attribute cannot be used on type aliases
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:639:5
    |
-LL |     #[link_section = "1800"] type T = S;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = ",1800"] type T = S;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -902,8 +902,8 @@ LL |     #[link_section = "1800"] type T = S;
 warning: `#[link_section]` attribute cannot be used on inherent impl blocks
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:645:5
    |
-LL |     #[link_section = "1800"] impl S { }
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = ",1800"] impl S { }
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -911,8 +911,8 @@ LL |     #[link_section = "1800"] impl S { }
 warning: `#[link_section]` attribute cannot be used on traits
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:651:5
    |
-LL |     #[link_section = "1800"]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     #[link_section = ",1800"]
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics
@@ -920,8 +920,8 @@ LL |     #[link_section = "1800"]
 warning: `#[link_section]` attribute cannot be used on required trait methods
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:657:9
    |
-LL |         #[link_section = "1800"]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+LL |         #[link_section = ",1800"]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions, inherent methods, provided trait methods, statics, and trait methods in impl blocks
@@ -1570,8 +1570,8 @@ LL | #![link_name = "1900"]
 warning: `#[link_section]` attribute cannot be used on crates
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:77:1
    |
-LL | #![link_section = "1800"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #![link_section = ",1800"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = help: `#[link_section]` can be applied to functions and statics

tests/ui/linkage-attr/link-section-macho.rs

@@ -0,0 +1,58 @@
+//@ add-minicore
+//@ compile-flags: --target aarch64-apple-darwin
+//@ needs-llvm-components: aarch64
+//@ ignore-backends: gcc
+#![feature(no_core, rustc_attrs, lang_items)]
+#![no_core]
+#![crate_type = "lib"]
+
+extern crate minicore;
+use minicore::*;
+
+#[unsafe(link_section = "foo")]
+//~^ ERROR invalid Mach-O section specifier
+#[unsafe(no_mangle)]
+fn missing_section() {}
+
+#[unsafe(link_section = "foo,")]
+//~^ ERROR invalid Mach-O section specifier
+#[unsafe(no_mangle)]
+fn empty_section() {}
+
+#[unsafe(link_section = "foo, ")]
+//~^ ERROR invalid Mach-O section specifier
+#[unsafe(no_mangle)]
+fn whitespace_section() {}
+
+#[unsafe(link_section = "foo,somelongwindedthing")]
+//~^ ERROR invalid Mach-O section specifier
+#[unsafe(no_mangle)]
+fn section_too_long() {}
+
+#[unsafe(link_section = "foo,bar")]
+#[unsafe(no_mangle)]
+fn segment_and_section() {}
+
+#[unsafe(link_section = "foo,bar,")]
+#[unsafe(no_mangle)]
+fn segment_and_section_and_comma() {}
+
+#[unsafe(link_section = ",foo")]
+#[unsafe(no_mangle)]
+fn missing_segment_is_fine() {}
+
+#[unsafe(link_section = "__TEXT,__stubs,symbol_stubs,none,16")]
+#[unsafe(no_mangle)]
+fn stub_size_decimal() {}
+
+#[unsafe(link_section = "__TEXT,__stubs,symbol_stubs,none,0x10")]
+#[unsafe(no_mangle)]
+fn stub_size_hex() {}
+
+#[unsafe(link_section = "__TEXT,__stubs,symbol_stubs,none,020")]
+#[unsafe(no_mangle)]
+fn stub_size_oct() {}
+
+#[unsafe(link_section = "__TEXT,__stubs,symbol_stubs,none,020,rest,is,ignored")]
+#[unsafe(no_mangle)]
+fn rest_is_ignored() {}

tests/ui/linkage-attr/link-section-macho.stderr

@@ -0,0 +1,37 @@
+error: invalid Mach-O section specifier
+  --> $DIR/link-section-macho.rs:12:25
+   |
+LL | #[unsafe(link_section = "foo")]
+   |                         ^^^^^ not a valid Mach-O section specifier
+   |
+   = note: a Mach-O section specifier requires a segment and a section, separated by a comma
+   = help: an example of a valid Mach-O section specifier is `__TEXT,__cstring`
+
+error: invalid Mach-O section specifier
+  --> $DIR/link-section-macho.rs:17:25
+   |
+LL | #[unsafe(link_section = "foo,")]
+   |                         ^^^^^^ not a valid Mach-O section specifier
+   |
+   = note: a Mach-O section specifier requires a segment and a section, separated by a comma
+   = help: an example of a valid Mach-O section specifier is `__TEXT,__cstring`
+
+error: invalid Mach-O section specifier
+  --> $DIR/link-section-macho.rs:22:25
+   |
+LL | #[unsafe(link_section = "foo, ")]
+   |                         ^^^^^^^ not a valid Mach-O section specifier
+   |
+   = note: a Mach-O section specifier requires a segment and a section, separated by a comma
+   = help: an example of a valid Mach-O section specifier is `__TEXT,__cstring`
+
+error: invalid Mach-O section specifier
+  --> $DIR/link-section-macho.rs:27:25
+   |
+LL | #[unsafe(link_section = "foo,somelongwindedthing")]
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ not a valid Mach-O section specifier
+   |
+   = note: section name `somelongwindedthing` is longer than 16 bytes
+
+error: aborting due to 4 previous errors
+

tests/ui/linkage-attr/link-section-placement.rs

@@ -2,37 +2,38 @@
 
 //@ run-pass
 
+#![feature(cfg_target_object_format)]
 // FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
 #![allow(static_mut_refs)]
 #![allow(non_upper_case_globals)]
-#[cfg(not(target_vendor = "apple"))]
-#[link_section = ".moretext"]
-fn i_live_in_more_text() -> &'static str {
-    "knock knock"
+
+cfg_select! {
+    target_object_format = "mach-o" => {
+        #[link_section = "__TEXT,__moretext"]
+        fn i_live_in_more_text() -> &'static str {
+            "knock knock"
+        }
+
+        #[link_section = "__RODATA,__imm"]
+        static magic: usize = 42;
+
+        #[link_section = "__DATA,__mut"]
+        static mut frobulator: usize = 0xdeadbeef;
+    }
+    _ => {
+        #[link_section = ".moretext"]
+        fn i_live_in_more_text() -> &'static str {
+            "knock knock"
+        }
+
+        #[link_section = ".imm"]
+        static magic: usize = 42;
+
+        #[link_section = ".mut"]
+        static mut frobulator: usize = 0xdeadbeef;
+    }
 }
 
-#[cfg(not(target_vendor = "apple"))]
-#[link_section = ".imm"]
-static magic: usize = 42;
-
-#[cfg(not(target_vendor = "apple"))]
-#[link_section = ".mut"]
-static mut frobulator: usize = 0xdeadbeef;
-
-#[cfg(target_vendor = "apple")]
-#[link_section = "__TEXT,__moretext"]
-fn i_live_in_more_text() -> &'static str {
-    "knock knock"
-}
-
-#[cfg(target_vendor = "apple")]
-#[link_section = "__RODATA,__imm"]
-static magic: usize = 42;
-
-#[cfg(target_vendor = "apple")]
-#[link_section = "__DATA,__mut"]
-static mut frobulator: usize = 0xdeadbeef;
-
 pub fn main() {
     unsafe {
         frobulator = 0x12345678;

tests/ui/lint/lint-unsafe-code.rs

@@ -48,8 +48,8 @@ impl AssocFnTrait for AssocFnFoo {
 #[export_name = "bar"] fn bar() {} //~ ERROR: declaration of a function with `export_name`
 #[export_name = "BAR"] static BAR: u32 = 5; //~ ERROR: declaration of a static with `export_name`
 
-#[link_section = ".example_section"] fn uwu() {} //~ ERROR: declaration of a function with `link_section`
-#[link_section = ".example_section"] static UWU: u32 = 5; //~ ERROR: declaration of a static with `link_section`
+#[link_section = "__TEXT,__text"] fn uwu() {} //~ ERROR: declaration of a function with `link_section`
+#[link_section = "__TEXT,__text"] static UWU: u32 = 5; //~ ERROR: declaration of a static with `link_section`
 
 struct AssocFnBar;
 

tests/ui/lint/lint-unsafe-code.stderr

@@ -54,16 +54,16 @@ LL | #[export_name = "BAR"] static BAR: u32 = 5;
 error: declaration of a function with `link_section`
   --> $DIR/lint-unsafe-code.rs:51:1
    |
-LL | #[link_section = ".example_section"] fn uwu() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[link_section = "__TEXT,__text"] fn uwu() {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the program's behavior with overridden link sections on items is unpredictable and Rust cannot provide guarantees when you manually override them
 
 error: declaration of a static with `link_section`
   --> $DIR/lint-unsafe-code.rs:52:1
    |
-LL | #[link_section = ".example_section"] static UWU: u32 = 5;
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[link_section = "__TEXT,__text"] static UWU: u32 = 5;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the program's behavior with overridden link sections on items is unpredictable and Rust cannot provide guarantees when you manually override them
 

tests/ui/lint/unused/unused-attr-duplicate.rs

@@ -61,8 +61,9 @@ macro_rules! foo {
 fn t1() {}
 
 #[must_use]
-#[must_use = "some message"]  //~ ERROR unused attribute
-//~^ WARN this was previously accepted
+#[must_use = "some message"]
+//~^ ERROR unused attribute
+//~| WARN this was previously accepted
 // No warnings for #[repr], would require more logic.
 #[repr(C)]
 #[repr(C)]
@@ -96,7 +97,7 @@ pub fn xyz() {}
 }
 
 #[export_name = "exported_symbol_name"]
-#[export_name = "exported_symbol_name2"]  //~ ERROR unused attribute
+#[export_name = "exported_symbol_name2"] //~ ERROR unused attribute
 //~^ WARN this was previously accepted
 pub fn export_test() {}
 
@@ -108,8 +109,8 @@ pub fn no_mangle_test() {}
 #[used] //~ ERROR unused attribute
 static FOO: u32 = 0;
 
-#[link_section = ".text"]
-#[link_section = ".bss"]
+#[link_section = "__TEXT,__text"]
+#[link_section = "__DATA,__mod_init_func"]
 //~^ ERROR unused attribute
 //~| WARN this was previously accepted
 pub extern "C" fn example() {}

tests/ui/lint/unused/unused-attr-duplicate.stderr

@@ -104,127 +104,127 @@ LL | #[must_use]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:70:1
+  --> $DIR/unused-attr-duplicate.rs:71:1
    |
 LL | #[non_exhaustive]
    | ^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:69:1
+  --> $DIR/unused-attr-duplicate.rs:70:1
    |
 LL | #[non_exhaustive]
    | ^^^^^^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:76:1
+  --> $DIR/unused-attr-duplicate.rs:77:1
    |
 LL | #[automatically_derived]
    | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:75:1
+  --> $DIR/unused-attr-duplicate.rs:76:1
    |
 LL | #[automatically_derived]
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:80:1
+  --> $DIR/unused-attr-duplicate.rs:81:1
    |
 LL | #[inline(never)]
    | ^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:79:1
+  --> $DIR/unused-attr-duplicate.rs:80:1
    |
 LL | #[inline(always)]
    | ^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:83:1
+  --> $DIR/unused-attr-duplicate.rs:84:1
    |
 LL | #[cold]
    | ^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:82:1
+  --> $DIR/unused-attr-duplicate.rs:83:1
    |
 LL | #[cold]
    | ^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:85:1
+  --> $DIR/unused-attr-duplicate.rs:86:1
    |
 LL | #[track_caller]
    | ^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:84:1
+  --> $DIR/unused-attr-duplicate.rs:85:1
    |
 LL | #[track_caller]
    | ^^^^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:93:5
+  --> $DIR/unused-attr-duplicate.rs:94:5
    |
 LL |     #[link_name = "rust_dbg_extern_identity_u32"]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:92:5
+  --> $DIR/unused-attr-duplicate.rs:93:5
    |
 LL |     #[link_name = "this_does_not_exist"]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:99:1
+  --> $DIR/unused-attr-duplicate.rs:100:1
    |
 LL | #[export_name = "exported_symbol_name2"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:98:1
+  --> $DIR/unused-attr-duplicate.rs:99:1
    |
 LL | #[export_name = "exported_symbol_name"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:104:1
+  --> $DIR/unused-attr-duplicate.rs:105:1
    |
 LL | #[no_mangle]
    | ^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:103:1
+  --> $DIR/unused-attr-duplicate.rs:104:1
    |
 LL | #[no_mangle]
    | ^^^^^^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:108:1
+  --> $DIR/unused-attr-duplicate.rs:109:1
    |
 LL | #[used]
    | ^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:107:1
+  --> $DIR/unused-attr-duplicate.rs:108:1
    |
 LL | #[used]
    | ^^^^^^^
 
 error: unused attribute
-  --> $DIR/unused-attr-duplicate.rs:112:1
+  --> $DIR/unused-attr-duplicate.rs:113:1
    |
-LL | #[link_section = ".bss"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
+LL | #[link_section = "__DATA,__mod_init_func"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
-  --> $DIR/unused-attr-duplicate.rs:111:1
+  --> $DIR/unused-attr-duplicate.rs:112:1
    |
-LL | #[link_section = ".text"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[link_section = "__TEXT,__text"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 
 error: unused attribute

tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.fixed

@@ -15,7 +15,7 @@ macro_rules! ident {
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         extern "C" fn bar() {}
-    }
+    };
 }
 
 macro_rules! ident2 {
@@ -24,26 +24,26 @@ macro_rules! ident2 {
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         extern "C" fn bars() {}
-    }
+    };
 }
 
 macro_rules! meta {
     ($m:meta) => {
         #[$m]
         extern "C" fn baz() {}
-    }
+    };
 }
 
 macro_rules! meta2 {
     ($m:meta) => {
         #[$m]
         extern "C" fn baw() {}
-    }
+    };
 }
 
 macro_rules! with_cfg_attr {
     () => {
-        #[cfg_attr(true, unsafe(link_section = ".custom_section"))]
+        #[cfg_attr(true, unsafe(link_section = "__TEXT,__custom"))]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         pub extern "C" fn abc() {}

tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.rs

@@ -15,7 +15,7 @@ macro_rules! ident {
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         extern "C" fn bar() {}
-    }
+    };
 }
 
 macro_rules! ident2 {
@@ -24,26 +24,26 @@ macro_rules! ident2 {
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         extern "C" fn bars() {}
-    }
+    };
 }
 
 macro_rules! meta {
     ($m:meta) => {
         #[$m]
         extern "C" fn baz() {}
-    }
+    };
 }
 
 macro_rules! meta2 {
     ($m:meta) => {
         #[$m]
         extern "C" fn baw() {}
-    }
+    };
 }
 
 macro_rules! with_cfg_attr {
     () => {
-        #[cfg_attr(true, link_section = ".custom_section")]
+        #[cfg_attr(true, link_section = "__TEXT,__custom")]
         //~^ ERROR: unsafe attribute used without unsafe
         //~| WARN this is accepted in the current edition
         pub extern "C" fn abc() {}

tests/ui/rust-2024/unsafe-attributes/unsafe-attributes-fix.stderr

@@ -79,7 +79,7 @@ LL |         #[unsafe($e = $l)]
 error: unsafe attribute used without unsafe
   --> $DIR/unsafe-attributes-fix.rs:46:26
    |
-LL |         #[cfg_attr(true, link_section = ".custom_section")]
+LL |         #[cfg_attr(true, link_section = "__TEXT,__custom")]
    |                          ^^^^^^^^^^^^ usage of unsafe attribute
 ...
 LL | with_cfg_attr!();
@@ -90,7 +90,7 @@ LL | with_cfg_attr!();
    = note: this error originates in the macro `with_cfg_attr` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: wrap the attribute in `unsafe(...)`
    |
-LL |         #[cfg_attr(true, unsafe(link_section = ".custom_section"))]
+LL |         #[cfg_attr(true, unsafe(link_section = "__TEXT,__custom"))]
    |                          +++++++                                +
 
 error: unsafe attribute used without unsafe