From 8d6c973c7f77e63a9c5d1ce4b7c71a37fcc46f4d Mon Sep 17 00:00:00 2001 From: Andrew Brown Date: Fri, 28 Jan 2022 09:48:59 -0800 Subject: Add support for control-flow protection This change adds a flag for configuring control-flow protection in the LLVM backend. In Clang, this flag is exposed as `-fcf-protection` with options `none|branch|return|full`. This convention is followed for `rustc`, though as a codegen option: `rustc -Z cf-protection=`. Co-authored-by: BlackHoleFox --- compiler/rustc_codegen_llvm/src/context.rs | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'compiler/rustc_codegen_llvm/src') diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs index 8672459b5da..373ae21d192 100644 --- a/compiler/rustc_codegen_llvm/src/context.rs +++ b/compiler/rustc_codegen_llvm/src/context.rs @@ -21,7 +21,8 @@ use rustc_middle::ty::layout::{ }; use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; use rustc_middle::{bug, span_bug}; -use rustc_session::config::{BranchProtection, CFGuard, CrateType, DebugInfo, PAuthKey, PacRet}; +use rustc_session::config::{BranchProtection, CFGuard, CFProtection}; +use rustc_session::config::{CrateType, DebugInfo, PAuthKey, PacRet}; use rustc_session::Session; use rustc_span::source_map::Span; use rustc_span::symbol::Symbol; @@ -287,6 +288,24 @@ pub unsafe fn create_module<'ll>( ); } + // Pass on the control-flow protection flags to LLVM (equivalent to `-fcf-protection` in Clang). + if let CFProtection::Branch | CFProtection::Full = sess.opts.debugging_opts.cf_protection { + llvm::LLVMRustAddModuleFlag( + llmod, + llvm::LLVMModFlagBehavior::Override, + "cf-protection-branch\0".as_ptr().cast(), + 1, + ) + } + if let CFProtection::Return | CFProtection::Full = sess.opts.debugging_opts.cf_protection { + llvm::LLVMRustAddModuleFlag( + llmod, + llvm::LLVMModFlagBehavior::Override, + "cf-protection-return\0".as_ptr().cast(), + 1, + ) + } + llmod } -- cgit 1.4.1-3-g733a5