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Disable DWARF in linker options for i686-unknown-uefi

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This fixes an lld warning:
> warning: linker stderr: rust-lld: section name .debug_frame is longer
> than 8 characters and will use a non-standard string table

See https://reviews.llvm.org/D69594 for details of where the warning was
added.

This warning only occurs with the i686 UEFI target, not x86_64 or
aarch64. The x86_64 target uses an LLVM target of
`x86_64-unknown-windows` and aarch64 uses `aarch64-unknown-windows`, but
i686 uses `i686-unknown-windows-gnu` (note the `-gnu`). See comments in
`i686_unknown_uefi.rs` for details of why.

The `.debug_frame` section should not actually be needed; UEFI targets
provide a separate PDB file for debugging. Disable DWARF (and by
extension the `.debug_frame` section) by passing `/DEBUG:NODWARF` to lld.

Tested with:
export RUSTC_LOG=rustc_codegen_ssa:🔙:link=info
cargo +stage1 build --release --target i686-unknown-uefi
This commit is contained in:
Nicholas Bishop 2025-02-09 15:04:38 -05:00
parent 124cc92199
commit 9da96a65e1
1 changed files with 8 additions and 1 deletions
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9
compiler/rustc_target/src/spec/targets/i686_unknown_uefi.rs
View file

@ -5,7 +5,7 @@
// The cdecl ABI is used. It differs from the stdcall or fastcall ABI.
// "i686-unknown-windows" is used to get the minimal subset of windows-specific features.
use crate::spec::{RustcAbi, Target, base};
use crate::spec::{LinkerFlavor, Lld, RustcAbi, Target, add_link_args, base};
pub(crate) fn target() -> Target {
let mut base = base::uefi_msvc::opts();
@ -24,6 +24,13 @@ pub(crate) fn target() -> Target {
base.features = "-mmx,-sse,+soft-float".into();
base.rustc_abi = Some(RustcAbi::X86Softfloat);
// Turn off DWARF. This fixes an lld warning, "section name .debug_frame is longer than 8
// characters and will use a non-standard string table". That section will not be created if
// DWARF is disabled.
//
// This is only needed in the i686 target due to using the `-gnu` LLVM target (see below).
add_link_args(&mut base.post_link_args, LinkerFlavor::Msvc(Lld::No), &["/DEBUG:NODWARF"]);
// Use -GNU here, because of the reason below:
// Background and Problem:
// If we use i686-unknown-windows, the LLVM IA32 MSVC generates compiler intrinsic