Record the sanitizer probes as expected and key objtool objects by relative path

config-divergences.toml

@@ -11,3 +11,19 @@
 [[divergence]]
 symbol = "CC_VERSION_TEXT"
 reason = "the first line of --version, which names the compiler and so always differs"
+
+[[divergence]]
+symbol = "CC_HAS_KASAN_*"
+reason = "rucc has no -fsanitize=kernel-address or kernel-hwaddress, and plan section 8.10 keeps the sanitizers out of the grade, with KASAN off in both builds"
+
+[[divergence]]
+symbol = "KASAN"
+reason = "only visible when the compiler can build it, see CC_HAS_KASAN_*"
+
+[[divergence]]
+symbol = "HAVE_KCSAN_COMPILER"
+reason = "rucc has no -fsanitize=thread, and plan section 8.10 keeps the sanitizers out of the grade, with KCSAN off in both builds"
+
+[[divergence]]
+symbol = "KCSAN"
+reason = "only visible when the compiler can build it, see HAVE_KCSAN_COMPILER"

crates/rk/src/flags.rs

@@ -76,14 +76,23 @@ pub fn load(out: &Path) -> Result<Commands, String> {
                     continue;
                 };
                 if let Some((object, words)) = parse_cmd(&text) {
-                    commands.insert(object, words);
+                    commands.insert(relative(&object, out), words);
                 }
             }
         }
     }
     Ok(commands)
 }
 
+/// An object's name relative to the output directory. objtool is built by its own makefile, which
+/// names its objects by their full path, so without this every one of them is in one build only.
+fn relative(object: &str, out: &Path) -> String {
+    Path::new(object).strip_prefix(out).map_or_else(
+        |_| object.to_string(),
+        |rest| rest.to_string_lossy().into_owned(),
+    )
+}
+
 /// A command made comparable: `CC` for the compiler, no persona, no output or dependency file,
 /// and `OUT` and `SRC` for the directories named in `dirs`, longest first.
 #[must_use]
@@ -289,6 +298,20 @@ mod tests {
         c
     }
 
+    #[test]
+    fn an_object_named_by_its_full_path_is_keyed_like_the_rest() {
+        let out = Path::new("/w/out/def-gcc");
+        assert_eq!(
+            relative("/w/out/def-gcc/tools/objtool/elf.o", out),
+            "tools/objtool/elf.o"
+        );
+        assert_eq!(relative("kernel/fork.o", out), "kernel/fork.o");
+        assert_eq!(
+            relative("/w/out/def-rucc/elf.o", out),
+            "/w/out/def-rucc/elf.o"
+        );
+    }
+
     #[test]
     fn a_cmd_file_gives_the_compile_command_without_what_follows() {
         let (object, words) = parse_cmd(GCC).unwrap();