bjoernager/rust
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Dispose llvm::TargetMachines prior to llvm::Context being disposed

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If the TargetMachine is disposed after the Context is disposed, it can
lead to use after frees in some cases.

I've observed this happening occasionally on code compiled for
aarch64-pc-windows-msvc using `-Zstack-protector=strong` but other users
have reported AVs from host aarch64-pc-windows-msvc compilers as well.
This commit is contained in:
Wesley Wiser 2023-11-29 17:36:45 -06:00
parent b10cfcd65f
commit 3323e4dc04
2 changed files with 18 additions and 6 deletions
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3
compiler/rustc_codegen_llvm/src/back/lto.rs
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@ -25,6 +25,7 @@ use std::ffi::{CStr, CString};
use std::fs::File;
use std::io;
use std::iter;
use std::mem::ManuallyDrop;
use std::path::Path;
use std::slice;
use std::sync::Arc;
@ -734,7 +735,7 @@ pub unsafe fn optimize_thin_module(
let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
let llmod_raw = parse_module(llcx, module_name, thin_module.data(), &diag_handler)? as *const _;
let mut module = ModuleCodegen {
module_llvm: ModuleLlvm { llmod_raw, llcx, tm },
module_llvm: ModuleLlvm { llmod_raw, llcx, tm: ManuallyDrop::new(tm) },
name: thin_module.name().to_string(),
kind: ModuleKind::Regular,
};