bjoernager/rust
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Add LLVM CFI support to the Rust compiler

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This commit adds LLVM Control Flow Integrity (CFI) support to the Rust
compiler. It initially provides forward-edge control flow protection for
Rust-compiled code only by aggregating function pointers in groups
identified by their number of arguments.

Forward-edge control flow protection for C or C++ and Rust -compiled
code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code
share the same virtual address space) will be provided in later work as
part of this project by defining and using compatible type identifiers
(see Type metadata in the design document in the tracking issue #89653).

LLVM CFI can be enabled with -Zsanitizer=cfi and requires LTO (i.e.,
-Clto).
This commit is contained in:
Ramon de C Valle 2021-10-07 15:33:13 -07:00
parent 1067e2ca5e
commit 5d30e93189
33 changed files with 271 additions and 20 deletions
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11
compiler/rustc_codegen_llvm/src/context.rs
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@ -221,6 +221,15 @@ pub unsafe fn create_module(
llvm::LLVMRustAddModuleFlag(llmod, avoid_plt, 1);
}
if sess.is_sanitizer_cfi_enabled() {
// FIXME(rcvalle): Add support for non canonical jump tables.
let canonical_jump_tables = "CFI Canonical Jump Tables\0".as_ptr().cast();
// FIXME(rcvalle): Add it with Override behavior flag--LLVMRustAddModuleFlag adds it with
// Warning behavior flag. Add support for specifying the behavior flag to
// LLVMRustAddModuleFlag.
llvm::LLVMRustAddModuleFlag(llmod, canonical_jump_tables, 1);
}
// Control Flow Guard is currently only supported by the MSVC linker on Windows.
if sess.target.is_like_msvc {
match sess.opts.cg.control_flow_guard {
@ -779,6 +788,8 @@ impl CodegenCx<'b, 'tcx> {
ifn!("llvm.instrprof.increment", fn(i8p, t_i64, t_i32, t_i32) -> void);
}
ifn!("llvm.type.test", fn(i8p, self.type_metadata()) -> i1);
if self.sess().opts.debuginfo != DebugInfo::None {
ifn!("llvm.dbg.declare", fn(self.type_metadata(), self.type_metadata()) -> void);
ifn!("llvm.dbg.value", fn(self.type_metadata(), t_i64, self.type_metadata()) -> void);