bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Rollup merge of #92877 - Amanieu:remove_llvm_nounwind, r=Mark-Simulacrum

Browse source 
Remove LLVMRustMarkAllFunctionsNounwind

This was originally introduced in #10916 as a way to remove all landing
pads when performing LTO. However this is no longer necessary today
since rustc properly marks all functions and call-sites as nounwind
where appropriate.

In fact this is incorrect in the presence of `extern "C-unwind"` which
must create a landing pad when compiled with `-C panic=abort` so that
foreign exceptions are caught and properly turned into aborts.
This commit is contained in:
Matthias Krüger 2022-01-17 20:07:07 +01:00 • committed by GitHub
commit 7f02604f3d
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
4 changed files with 1 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

17
compiler/rustc_codegen_llvm/src/back/lto.rs
View file

@ -349,13 +349,6 @@ fn fat_lto(
);
save_temp_bitcode(cgcx, &module, "lto.after-restriction");
}
if cgcx.no_landing_pads {
unsafe {
llvm::LLVMRustMarkAllFunctionsNounwind(llmod);
}
save_temp_bitcode(cgcx, &module, "lto.after-nounwind");
}
}
Ok(LtoModuleCodegen::Fat { module: Some(module), _serialized_bitcode: serialized_bitcode })
@ -770,16 +763,6 @@ pub unsafe fn optimize_thin_module(
return Err(write::llvm_err(&diag_handler, msg));
}
// Like with "fat" LTO, get some better optimizations if landing pads
// are disabled by removing all landing pads.
if cgcx.no_landing_pads {
let _timer = cgcx
.prof
.generic_activity_with_arg("LLVM_thin_lto_remove_landing_pads", thin_module.name());
llvm::LLVMRustMarkAllFunctionsNounwind(llmod);
save_temp_bitcode(cgcx, &module, "thin-lto-after-nounwind");
}
// Up next comes the per-module local analyses that we do for Thin LTO.
// Each of these functions is basically copied from the LLVM
// implementation and then tailored to suit this implementation. Ideally

1
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
View file

@ -2320,7 +2320,6 @@ extern "C" {
pub fn LLVMRustSetNormalizedTarget(M: &Module, triple: *const c_char);
pub fn LLVMRustAddAlwaysInlinePass(P: &PassManagerBuilder, AddLifetimes: bool);
pub fn LLVMRustRunRestrictionPass(M: &Module, syms: *const *const c_char, len: size_t);
pub fn LLVMRustMarkAllFunctionsNounwind(M: &Module);
pub fn LLVMRustOpenArchive(path: *const c_char) -> Option<&'static mut Archive>;
pub fn LLVMRustArchiveIteratorNew(AR: &Archive) -> &mut ArchiveIterator<'_>;