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Fix dso_local for external statics with linkage #150494

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Fix dso_local for external statics with linkage #150494

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1ff953d
Fix and expand direct-access-external-data test
nbdd0121 Dec 29, 2025
5467a39
Fix dso_local for external statics with linkage
nbdd0121 Dec 29, 2025
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4 changes: 4 additions & 0 deletions compiler/rustc_codegen_llvm/src/consts.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -187,6 +187,10 @@ fn check_and_apply_linkage<'ll, 'tcx>(
};
llvm::set_linkage(g1, base::linkage_to_llvm(linkage));

// Normally this is done in `get_static_inner`, but when as we generate an internal global,
// it will apply the dso_local to the internal global instead, so do it here, too.
cx.assume_dso_local(g1, true);

// Declare an internal global `extern_with_linkage_foo` which
// is initialized with the address of `foo`. If `foo` is
// discarded during linking (for example, if `foo` has weak
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47 changes: 37 additions & 10 deletions tests/codegen-llvm/direct-access-external-data.rs
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@@ -1,21 +1,48 @@
//@ only-loongarch64-unknown-linux-gnu
//@ ignore-powerpc64 (handles dso_local differently)
//@ ignore-apple (handles dso_local differently)

//@ revisions: DEFAULT DIRECT INDIRECT
//@ revisions: DEFAULT PIE DIRECT INDIRECT
//@ [DEFAULT] compile-flags: -C relocation-model=static
//@ [DIRECT] compile-flags: -C relocation-model=static -Z direct-access-external-data=yes
//@ [PIE] compile-flags: -C relocation-model=pie
//@ [DIRECT] compile-flags: -C relocation-model=pie -Z direct-access-external-data=yes
//@ [INDIRECT] compile-flags: -C relocation-model=static -Z direct-access-external-data=no

#![crate_type = "rlib"]
#![feature(linkage)]

// DEFAULT: @VAR = external {{.*}} global i32
// DIRECT: @VAR = external dso_local {{.*}} global i32
// INDIRECT: @VAR = external {{.*}} global i32
unsafe extern "C" {
// CHECK: @VAR = external
// DEFAULT-SAME: dso_local
// PIE-NOT: dso_local
// DIRECT-SAME: dso_local
// INDIRECT-NOT: dso_local
// CHECK-SAME: global i32
safe static VAR: i32;

extern "C" {
static VAR: i32;
// When "linkage" is used, we generate an indirection global.
// Check dso_local is still applied to the actual global.
// CHECK: @EXTERNAL = external
// DEFAULT-SAME: dso_local
// PIE-NOT: dso_local
// DIRECT-SAME: dso_local
// INDIRECT-NOT: dso_local
// CHECK-SAME: global i8
#[linkage = "external"]
safe static EXTERNAL: *const u32;

// CHECK: @WEAK = extern_weak
// DEFAULT-SAME: dso_local
// PIE-NOT: dso_local
// DIRECT-SAME: dso_local
// INDIRECT-NOT: dso_local
// CHECK-SAME: global i8
#[linkage = "extern_weak"]
safe static WEAK: *const u32;
}

#[no_mangle]
pub fn get() -> i32 {
unsafe { VAR }
pub fn refer() {
core::hint::black_box(VAR);
core::hint::black_box(EXTERNAL);
core::hint::black_box(WEAK);
}
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