convert ehcont-guard to an unstable option

compiler/rustc_codegen_llvm/src/context.rs

@@ -350,8 +350,9 @@ pub unsafe fn create_module<'ll>(
             1,
         );
     }
+
     // Set module flag to enable Windows EHCont Guard (/guard:ehcont).
-    if sess.opts.cg.ehcont_guard {
+    if sess.opts.unstable_opts.ehcont_guard {
         llvm::LLVMRustAddModuleFlag(
             llmod,
             llvm::LLVMModFlagBehavior::Warning,

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -2379,7 +2379,7 @@ fn add_order_independent_options(
     }
 
     // OBJECT-FILES-NO, AUDIT-ORDER
-    if sess.opts.cg.ehcont_guard {
+    if sess.opts.unstable_opts.ehcont_guard {
         cmd.ehcont_guard();
     }
 

compiler/rustc_session/src/options.rs

@@ -1387,8 +1387,6 @@ pub(crate) fn parse_llvm_module_flag(
         "allow the linker to link its default libraries (default: no)"),
     dlltool: Option<PathBuf> = (None, parse_opt_pathbuf, [UNTRACKED],
         "import library generation tool (ignored except when targeting windows-gnu)"),
-    ehcont_guard: bool = (false, parse_bool, [TRACKED],
-        "generate Windows EHCont Guard tables"),
     embed_bitcode: bool = (true, parse_bool, [TRACKED],
         "emit bitcode in rlibs (default: yes)"),
     extra_filename: String = (String::new(), parse_string, [UNTRACKED],
@@ -1584,6 +1582,8 @@ pub(crate) fn parse_llvm_module_flag(
         "version of DWARF debug information to emit (default: 2 or 4, depending on platform)"),
     dylib_lto: bool = (false, parse_bool, [UNTRACKED],
         "enables LTO for dylib crate type"),
+    ehcont_guard: bool = (false, parse_bool, [TRACKED],
+        "generate Windows EHCont Guard tables"),
     emit_stack_sizes: bool = (false, parse_bool, [UNTRACKED],
         "emit a section containing stack size metadata (default: no)"),
     emit_thin_lto: bool = (true, parse_bool, [TRACKED],

tests/codegen/ehcontguard_enabled.rs

@@ -1,4 +1,4 @@
-// compile-flags: -C ehcont_guard
+// compile-flags: -Z ehcont-guard
 
 #![crate_type = "lib"]