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| author | Dylan DPC <99973273+Dylan-DPC@users.noreply.github.com> | 2022-07-18 21:14:43 +0530 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-07-18 21:14:43 +0530 |
| commit | a027b01f33e3280dff1a7be09d6090151d3f78a9 (patch) | |
| tree | f6bfe00253a2bb38b997bfd862b1f2e48948fa0a /compiler/rustc_codegen_llvm/src/attributes.rs | |
| parent | 5ccdf1f6f7651001e3b15f48c6f2e5d0b56accf2 (diff) | |
| parent | 530b5da49b822fd65214ecbe85455114e0ce725f (diff) | |
| download | rust-a027b01f33e3280dff1a7be09d6090151d3f78a9.tar.gz rust-a027b01f33e3280dff1a7be09d6090151d3f78a9.zip | |
Rollup merge of #98998 - workingjubilee:naked-means-no-clothes-enforcement-technology, r=Amanieu
Remove branch target prologues from `#[naked] fn` This patch hacks around rust-lang/rust#98768 for now via injecting appropriate attributes into the LLVMIR we emit for naked functions. I intend to pursue this upstream so that these attributes can be removed in general, but it's slow going wading through C++ for me.
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/attributes.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/attributes.rs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs index 32bfa5094c3..62da99ac3fb 100644 --- a/compiler/rustc_codegen_llvm/src/attributes.rs +++ b/compiler/rustc_codegen_llvm/src/attributes.rs @@ -299,6 +299,12 @@ pub fn from_fn_attrs<'ll, 'tcx>( } if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) { to_add.push(AttributeKind::Naked.create_attr(cx.llcx)); + // HACK(jubilee): "indirect branch tracking" works by attaching prologues to functions. + // And it is a module-level attribute, so the alternative is pulling naked functions into new LLVM modules. + // Otherwise LLVM's "naked" functions come with endbr prefixes per https://github.com/rust-lang/rust/issues/98768 + to_add.push(AttributeKind::NoCfCheck.create_attr(cx.llcx)); + // Need this for AArch64. + to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false")); } if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR) { // apply to return place instead of function (unlike all other attributes applied in this function) |