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Auto merge of #93439 - abrown:cf-protection, r=nagisa

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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=<none|branch|return|full>`. Tracking issue for future work is #93754.
This commit is contained in:
bors 2022-02-15 21:20:49 +00:00
commit 09cb29c64c
5 changed files with 141 additions and 5 deletions
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21
compiler/rustc_codegen_llvm/src/context.rs
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@ -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
}