diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs index ed50515b70716..325ff362c6520 100644 --- a/compiler/rustc_codegen_llvm/src/context.rs +++ b/compiler/rustc_codegen_llvm/src/context.rs @@ -443,6 +443,15 @@ pub(crate) unsafe fn create_module<'ll>( } } + if sess.opts.unstable_opts.indirect_branch_cs_prefix { + llvm::add_module_flag_u32( + llmod, + llvm::ModuleFlagMergeBehavior::Override, + "indirect_branch_cs_prefix", + 1, + ); + } + match (sess.opts.unstable_opts.small_data_threshold, sess.target.small_data_threshold_support()) { // Set up the small-data optimization limit for architectures that use diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs index 0ceda2201344e..b8accd05c0b19 100644 --- a/compiler/rustc_interface/src/tests.rs +++ b/compiler/rustc_interface/src/tests.rs @@ -802,6 +802,7 @@ fn test_unstable_options_tracking_hash() { tracked!(function_sections, Some(false)); tracked!(human_readable_cgu_names, true); tracked!(incremental_ignore_spans, true); + tracked!(indirect_branch_cs_prefix, true); tracked!(inline_mir, Some(true)); tracked!(inline_mir_hint_threshold, Some(123)); tracked!(inline_mir_threshold, Some(123)); diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs index b95ebfbe89f24..2299089fd867d 100644 --- a/compiler/rustc_session/src/options.rs +++ b/compiler/rustc_session/src/options.rs @@ -2249,6 +2249,8 @@ options! { - hashes of green query instances - hash collisions of query keys - hash collisions when creating dep-nodes"), + indirect_branch_cs_prefix: bool = (false, parse_bool, [TRACKED TARGET_MODIFIER], + "add cs prefix to call and jmp to indirect thunk (default: no)"), inline_llvm: bool = (true, parse_bool, [TRACKED], "enable LLVM inlining (default: yes)"), inline_mir: Option = (None, parse_opt_bool, [TRACKED], diff --git a/tests/codegen/indirect-branch-cs-prefix.rs b/tests/codegen/indirect-branch-cs-prefix.rs new file mode 100644 index 0000000000000..a00b63a497081 --- /dev/null +++ b/tests/codegen/indirect-branch-cs-prefix.rs @@ -0,0 +1,18 @@ +// Test that the `indirect_branch_cs_prefix` module attribute is (not) emitted when the +// `-Zindirect-branch-cs-prefix` flag is (not) set. + +//@ add-core-stubs +//@ revisions: unset set +//@ needs-llvm-components: x86 +//@ compile-flags: --target x86_64-unknown-linux-gnu +//@ [set] compile-flags: -Zindirect-branch-cs-prefix + +#![crate_type = "lib"] +#![feature(no_core, lang_items)] +#![no_core] + +#[lang = "sized"] +trait Sized {} + +// unset-NOT: !{{[0-9]+}} = !{i32 4, !"indirect_branch_cs_prefix", i32 1} +// set: !{{[0-9]+}} = !{i32 4, !"indirect_branch_cs_prefix", i32 1}