diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 50a35fe3dcf1d..6b31f14410d2f 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -12,7 +12,7 @@ use rustc_codegen_ssa::traits::*;
use crate::callee::get_fn;
use rustc::bug;
use rustc::mir::mono::CodegenUnit;
-use rustc::session::config::{self, DebugInfo};
+use rustc::session::config::{self, CFGuard, DebugInfo};
use rustc::session::Session;
use rustc::ty::layout::{
FnAbiExt, HasParamEnv, LayoutError, LayoutOf, PointeeInfo, Size, TyLayout, VariantIdx,
@@ -227,6 +227,16 @@ pub unsafe fn create_module(
llvm::LLVMRustAddModuleFlag(llmod, avoid_plt, 1);
}
+ // Set module flags to enable Windows Control Flow Guard (/guard:cf) metadata
+ // only (`cfguard=1`) or metadata and checks (`cfguard=2`).
+ match sess.opts.debugging_opts.control_flow_guard {
+ CFGuard::Disabled => {}
+ CFGuard::NoChecks => {
+ llvm::LLVMRustAddModuleFlag(llmod, "cfguard\0".as_ptr() as *const _, 1)
+ }
+ CFGuard::Checks => llvm::LLVMRustAddModuleFlag(llmod, "cfguard\0".as_ptr() as *const _, 2),
+ }
+
llmod
}
diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index f56a4170c0a4b..bc0322ffe1d48 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -1,7 +1,7 @@
use rustc::middle::cstore::{EncodedMetadata, LibSource, NativeLibrary, NativeLibraryKind};
use rustc::middle::dependency_format::Linkage;
use rustc::session::config::{
- self, DebugInfo, OutputFilenames, OutputType, PrintRequest, Sanitizer,
+ self, CFGuard, DebugInfo, OutputFilenames, OutputType, PrintRequest, Sanitizer,
};
use rustc::session::search_paths::PathKind;
/// For all the linkers we support, and information they might
@@ -1294,6 +1294,10 @@ fn link_args<'a, B: ArchiveBuilder<'a>>(
cmd.pgo_gen();
}
+ if sess.opts.debugging_opts.control_flow_guard != CFGuard::Disabled {
+ cmd.control_flow_guard();
+ }
+
// FIXME (#2397): At some point we want to rpath our guesses as to
// where extern libraries might live, based on the
// addl_lib_search_paths
diff --git a/src/librustc_codegen_ssa/back/linker.rs b/src/librustc_codegen_ssa/back/linker.rs
index 695f171dfb49c..5aafb8a12d74b 100644
--- a/src/librustc_codegen_ssa/back/linker.rs
+++ b/src/librustc_codegen_ssa/back/linker.rs
@@ -106,6 +106,7 @@ pub trait Linker {
fn no_relro(&mut self);
fn optimize(&mut self);
fn pgo_gen(&mut self);
+ fn control_flow_guard(&mut self);
fn debuginfo(&mut self);
fn no_default_libraries(&mut self);
fn build_dylib(&mut self, out_filename: &Path);
@@ -360,6 +361,10 @@ impl<'a> Linker for GccLinker<'a> {
self.cmd.arg("__llvm_profile_runtime");
}
+ fn control_flow_guard(&mut self) {
+ self.sess.warn("Windows Control Flow Guard is not supported by this linker.");
+ }
+
fn debuginfo(&mut self) {
if let DebugInfo::None = self.sess.opts.debuginfo {
// If we are building without debuginfo enabled and we were called with
@@ -660,6 +665,10 @@ impl<'a> Linker for MsvcLinker<'a> {
// Nothing needed here.
}
+ fn control_flow_guard(&mut self) {
+ self.cmd.arg("/guard:cf");
+ }
+
fn debuginfo(&mut self) {
// This will cause the Microsoft linker to generate a PDB file
// from the CodeView line tables in the object files.
@@ -862,6 +871,10 @@ impl<'a> Linker for EmLinker<'a> {
// noop, but maybe we need something like the gnu linker?
}
+ fn control_flow_guard(&mut self) {
+ self.sess.warn("Windows Control Flow Guard is not supported by this linker.");
+ }
+
fn debuginfo(&mut self) {
// Preserve names or generate source maps depending on debug info
self.cmd.arg(match self.sess.opts.debuginfo {
@@ -1058,6 +1071,10 @@ impl<'a> Linker for WasmLd<'a> {
fn debuginfo(&mut self) {}
+ fn control_flow_guard(&mut self) {
+ self.sess.warn("Windows Control Flow Guard is not supported by this linker.");
+ }
+
fn no_default_libraries(&mut self) {}
fn build_dylib(&mut self, _out_filename: &Path) {
@@ -1233,6 +1250,10 @@ impl<'a> Linker for PtxLinker<'a> {
fn no_default_libraries(&mut self) {}
+ fn control_flow_guard(&mut self) {
+ self.sess.warn("Windows Control Flow Guard is not supported by this linker.");
+ }
+
fn build_dylib(&mut self, _out_filename: &Path) {}
fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType) {}
diff --git a/src/librustc_session/config.rs b/src/librustc_session/config.rs
index aa492b566e59e..813d14d616d42 100644
--- a/src/librustc_session/config.rs
+++ b/src/librustc_session/config.rs
@@ -70,6 +70,19 @@ impl FromStr for Sanitizer {
}
}
+/// The different settings that the `-Z control_flow_guard` flag can have.
+#[derive(Clone, Copy, PartialEq, Hash, Debug)]
+pub enum CFGuard {
+ /// Do not emit Control Flow Guard metadata or checks.
+ Disabled,
+
+ /// Emit Control Flow Guard metadata but no checks.
+ NoChecks,
+
+ /// Emit Control Flow Guard metadata and checks.
+ Checks,
+}
+
#[derive(Clone, Copy, Debug, PartialEq, Hash)]
pub enum OptLevel {
No, // -O0
@@ -1980,8 +1993,8 @@ impl PpMode {
/// how the hash should be calculated when adding a new command-line argument.
crate mod dep_tracking {
use super::{
- CrateType, DebugInfo, ErrorOutputType, LinkerPluginLto, LtoCli, OptLevel, OutputTypes,
- Passes, Sanitizer, SwitchWithOptPath, SymbolManglingVersion,
+ CFGuard, CrateType, DebugInfo, ErrorOutputType, LinkerPluginLto, LtoCli, OptLevel,
+ OutputTypes, Passes, Sanitizer, SwitchWithOptPath, SymbolManglingVersion,
};
use crate::lint;
use crate::utils::NativeLibraryKind;
@@ -2053,6 +2066,7 @@ crate mod dep_tracking {
impl_dep_tracking_hash_via_hash!(NativeLibraryKind);
impl_dep_tracking_hash_via_hash!(Sanitizer);
impl_dep_tracking_hash_via_hash!(Option<Sanitizer>);
+ impl_dep_tracking_hash_via_hash!(CFGuard);
impl_dep_tracking_hash_via_hash!(TargetTriple);
impl_dep_tracking_hash_via_hash!(Edition);
impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
diff --git a/src/librustc_session/options.rs b/src/librustc_session/options.rs
index 34da2188a51d2..f7f8ec8604561 100644
--- a/src/librustc_session/options.rs
+++ b/src/librustc_session/options.rs
@@ -263,6 +263,8 @@ macro_rules! options {
pub const parse_sanitizer_list: Option<&str> =
Some("comma separated list of sanitizers");
pub const parse_sanitizer_memory_track_origins: Option<&str> = None;
+ pub const parse_cfguard: Option<&str> =
+ Some("either `disabled`, `nochecks`, or `checks`");
pub const parse_linker_flavor: Option<&str> =
Some(::rustc_target::spec::LinkerFlavor::one_of());
pub const parse_optimization_fuel: Option<&str> =
@@ -288,7 +290,7 @@ macro_rules! options {
#[allow(dead_code)]
mod $mod_set {
use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto, SwitchWithOptPath,
- SymbolManglingVersion};
+ SymbolManglingVersion, CFGuard};
use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
use std::path::PathBuf;
use std::str::FromStr;
@@ -499,6 +501,16 @@ macro_rules! options {
}
}
+ fn parse_cfguard(slot: &mut CFGuard, v: Option<&str>) -> bool {
+ match v {
+ Some("disabled") => *slot = CFGuard::Disabled,
+ Some("nochecks") => *slot = CFGuard::NoChecks,
+ Some("checks") => *slot = CFGuard::Checks,
+ _ => return false,
+ }
+ true
+ }
+
fn parse_linker_flavor(slote: &mut Option<LinkerFlavor>, v: Option<&str>) -> bool {
match v.and_then(LinkerFlavor::from_str) {
Some(lf) => *slote = Some(lf),
@@ -950,6 +962,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
(such as entering an empty infinite loop) by inserting llvm.sideeffect"),
deduplicate_diagnostics: Option<bool> = (None, parse_opt_bool, [UNTRACKED],
"deduplicate identical diagnostics"),
+ control_flow_guard: CFGuard = (CFGuard::Disabled, parse_cfguard, [UNTRACKED],
+ "use Windows Control Flow Guard (`disabled`, `nochecks` or `checks`)"),
no_link: bool = (false, parse_bool, [TRACKED],
"compile without linking"),
}
diff --git a/src/test/codegen/cfguard_checks.rs b/src/test/codegen/cfguard_checks.rs
new file mode 100644
index 0000000000000..40a7353eac045
--- /dev/null
+++ b/src/test/codegen/cfguard_checks.rs
@@ -0,0 +1,10 @@
+// compile-flags: -Z control_flow_guard=checks
+
+#![crate_type = "lib"]
+
+// A basic test function.
+pub fn test() {
+}
+
+// Ensure the module flag cfguard=2 is present
+// CHECK: !"cfguard", i32 2
diff --git a/src/test/codegen/cfguard_disabled.rs b/src/test/codegen/cfguard_disabled.rs
new file mode 100644
index 0000000000000..d1747931e15c8
--- /dev/null
+++ b/src/test/codegen/cfguard_disabled.rs
@@ -0,0 +1,10 @@
+// compile-flags: -Z control_flow_guard=disabled
+
+#![crate_type = "lib"]
+
+// A basic test function.
+pub fn test() {
+}
+
+// Ensure the module flag cfguard is not present
+// CHECK-NOT: !"cfguard"
diff --git a/src/test/codegen/cfguard_nochecks.rs b/src/test/codegen/cfguard_nochecks.rs
new file mode 100644
index 0000000000000..c5d7afbae257b
--- /dev/null
+++ b/src/test/codegen/cfguard_nochecks.rs
@@ -0,0 +1,10 @@
+// compile-flags: -Z control_flow_guard=nochecks
+
+#![crate_type = "lib"]
+
+// A basic test function.
+pub fn test() {
+}
+
+// Ensure the module flag cfguard=1 is present
+// CHECK: !"cfguard", i32 1