Add [TRACKED_NO_CRATE_HASH] and [SUBSTRUCT] directives

This is necessary for options that should invalidate the incremental
hash but *not* affect the crate hash (e.g. --remap-path-prefix).

This doesn't add `for_crate_hash` to the trait directly because it's not
relevant for *types*, only for *options*, which are fields on a larger
struct. Instead, it adds a new `SUBSTRUCT` directive for options, which
does take a `for_crate_hash` parameter.

- Use TRACKED_NO_CRATE_HASH for --remap-path-prefix
- Add test that `remap_path_prefix` is tracked
- Reduce duplication in the test suite to avoid future churn

Author: jyn514

compiler/rustc_incremental/src/persist/load.rs

@@ -104,7 +104,7 @@ pub fn load_dep_graph(sess: &Session) -> DepGraphFuture {
     // Fortunately, we just checked that this isn't the case.
     let path = dep_graph_path_from(&sess.incr_comp_session_dir());
     let report_incremental_info = sess.opts.debugging_opts.incremental_info;
-    let expected_hash = sess.opts.dep_tracking_hash();
+    let expected_hash = sess.opts.dep_tracking_hash(false);
 
     let mut prev_work_products = FxHashMap::default();
     let nightly_build = sess.is_nightly_build();

compiler/rustc_incremental/src/persist/save.rs

@@ -219,7 +219,7 @@ pub fn build_dep_graph(
     }
 
     // First encode the commandline arguments hash
-    if let Err(err) = sess.opts.dep_tracking_hash().encode(&mut encoder) {
+    if let Err(err) = sess.opts.dep_tracking_hash(false).encode(&mut encoder) {
         sess.err(&format!(
             "failed to write dependency graph hash `{}`: {}",
             path_buf.display(),

compiler/rustc_interface/src/tests.rs

@@ -19,6 +19,7 @@ use rustc_span::symbol::sym;
 use rustc_span::SourceFileHashAlgorithm;
 use rustc_target::spec::{CodeModel, LinkerFlavor, MergeFunctions, PanicStrategy};
 use rustc_target::spec::{RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo, TlsModel};
+
 use std::collections::{BTreeMap, BTreeSet};
 use std::iter::FromIterator;
 use std::num::NonZeroUsize;
@@ -74,6 +75,27 @@ fn mk_map<K: Ord, V>(entries: Vec<(K, V)>) -> BTreeMap<K, V> {
     BTreeMap::from_iter(entries.into_iter())
 }
 
+fn assert_same_clone(x: &Options) {
+    assert_eq!(x.dep_tracking_hash(true), x.clone().dep_tracking_hash(true));
+    assert_eq!(x.dep_tracking_hash(false), x.clone().dep_tracking_hash(false));
+}
+
+fn assert_same_hash(x: &Options, y: &Options) {
+    assert_eq!(x.dep_tracking_hash(true), y.dep_tracking_hash(true));
+    assert_eq!(x.dep_tracking_hash(false), y.dep_tracking_hash(false));
+    // Check clone
+    assert_same_clone(x);
+    assert_same_clone(y);
+}
+
+fn assert_different_hash(x: &Options, y: &Options) {
+    assert_ne!(x.dep_tracking_hash(true), y.dep_tracking_hash(true));
+    assert_ne!(x.dep_tracking_hash(false), y.dep_tracking_hash(false));
+    // Check clone
+    assert_same_clone(x);
+    assert_same_clone(y);
+}
+
 // When the user supplies --test we should implicitly supply --cfg test
 #[test]
 fn test_switch_implies_cfg_test() {
@@ -130,14 +152,9 @@ fn test_output_types_tracking_hash_different_paths() {
     v2.output_types = OutputTypes::new(&[(OutputType::Exe, Some(PathBuf::from("/some/thing")))]);
     v3.output_types = OutputTypes::new(&[(OutputType::Exe, None)]);
 
-    assert!(v1.dep_tracking_hash() != v2.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() != v3.dep_tracking_hash());
-    assert!(v2.dep_tracking_hash() != v3.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
+    assert_different_hash(&v1, &v2);
+    assert_different_hash(&v1, &v3);
+    assert_different_hash(&v2, &v3);
 }
 
 #[test]
@@ -155,10 +172,7 @@ fn test_output_types_tracking_hash_different_construction_order() {
         (OutputType::Exe, Some(PathBuf::from("./some/thing"))),
     ]);
 
-    assert_eq!(v1.dep_tracking_hash(), v2.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
+    assert_same_hash(&v1, &v2);
 }
 
 #[test]
@@ -182,14 +196,9 @@ fn test_externs_tracking_hash_different_construction_order() {
         (String::from("d"), new_public_extern_entry(vec!["f", "e"])),
     ]));
 
-    assert_eq!(v1.dep_tracking_hash(), v2.dep_tracking_hash());
-    assert_eq!(v1.dep_tracking_hash(), v3.dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v3.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
+    assert_same_hash(&v1, &v2);
+    assert_same_hash(&v1, &v3);
+    assert_same_hash(&v2, &v3);
 }
 
 #[test]
@@ -219,14 +228,9 @@ fn test_lints_tracking_hash_different_values() {
         (String::from("d"), Level::Deny),
     ];
 
-    assert!(v1.dep_tracking_hash() != v2.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() != v3.dep_tracking_hash());
-    assert!(v2.dep_tracking_hash() != v3.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
+    assert_different_hash(&v1, &v2);
+    assert_different_hash(&v1, &v3);
+    assert_different_hash(&v2, &v3);
 }
 
 #[test]
@@ -248,11 +252,7 @@ fn test_lints_tracking_hash_different_construction_order() {
         (String::from("d"), Level::Forbid),
     ];
 
-    assert_eq!(v1.dep_tracking_hash(), v2.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
+    assert_same_hash(&v1, &v2);
 }
 
 #[test]
@@ -292,15 +292,9 @@ fn test_search_paths_tracking_hash_different_order() {
     v4.search_paths.push(SearchPath::from_cli_opt("dependency=ghi", JSON));
     v4.search_paths.push(SearchPath::from_cli_opt("framework=jkl", JSON));
 
-    assert!(v1.dep_tracking_hash() == v2.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() == v3.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() == v4.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
-    assert_eq!(v4.dep_tracking_hash(), v4.clone().dep_tracking_hash());
+    assert_same_hash(&v1, &v2);
+    assert_same_hash(&v1, &v3);
+    assert_same_hash(&v1, &v4);
 }
 
 #[test]
@@ -338,15 +332,9 @@ fn test_native_libs_tracking_hash_different_values() {
         (String::from("c"), None, NativeLibKind::Unspecified),
     ];
 
-    assert!(v1.dep_tracking_hash() != v2.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() != v3.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() != v4.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
-    assert_eq!(v4.dep_tracking_hash(), v4.clone().dep_tracking_hash());
+    assert_different_hash(&v1, &v2);
+    assert_different_hash(&v1, &v3);
+    assert_different_hash(&v1, &v4);
 }
 
 #[test]
@@ -374,14 +362,9 @@ fn test_native_libs_tracking_hash_different_order() {
         (String::from("b"), None, NativeLibKind::Framework),
     ];
 
-    assert!(v1.dep_tracking_hash() == v2.dep_tracking_hash());
-    assert!(v1.dep_tracking_hash() == v3.dep_tracking_hash());
-    assert!(v2.dep_tracking_hash() == v3.dep_tracking_hash());
-
-    // Check clone
-    assert_eq!(v1.dep_tracking_hash(), v1.clone().dep_tracking_hash());
-    assert_eq!(v2.dep_tracking_hash(), v2.clone().dep_tracking_hash());
-    assert_eq!(v3.dep_tracking_hash(), v3.clone().dep_tracking_hash());
+    assert_same_hash(&v1, &v2);
+    assert_same_hash(&v1, &v3);
+    assert_same_hash(&v2, &v3);
 }
 
 #[test]
@@ -393,7 +376,7 @@ fn test_codegen_options_tracking_hash() {
         ($name: ident, $non_default_value: expr) => {
             assert_ne!(opts.cg.$name, $non_default_value);
             opts.cg.$name = $non_default_value;
-            assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+            assert_same_hash(&reference, &opts);
         };
     }
 
@@ -419,7 +402,7 @@ fn test_codegen_options_tracking_hash() {
             opts = reference.clone();
             assert_ne!(opts.cg.$name, $non_default_value);
             opts.cg.$name = $non_default_value;
-            assert_ne!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+            assert_different_hash(&reference, &opts);
         };
     }
 
@@ -456,6 +439,28 @@ fn test_codegen_options_tracking_hash() {
     tracked!(target_feature, String::from("all the features, all of them"));
 }
 
+#[test]
+fn test_top_level_options_tracked_no_crate() {
+    let reference = Options::default();
+    let mut opts;
+
+    macro_rules! tracked {
+        ($name: ident, $non_default_value: expr) => {
+            opts = reference.clone();
+            assert_ne!(opts.$name, $non_default_value);
+            opts.$name = $non_default_value;
+            // The crate hash should be the same
+            assert_eq!(reference.dep_tracking_hash(true), opts.dep_tracking_hash(true));
+            // The incremental hash should be different
+            assert_ne!(reference.dep_tracking_hash(false), opts.dep_tracking_hash(false));
+        };
+    }
+
+    // Make sure that changing a [TRACKED_NO_CRATE_HASH] option leaves the crate hash unchanged but changes the incremental hash.
+    // This list is in alphabetical order.
+    tracked!(remap_path_prefix, vec![("/home/bors/rust".into(), "src".into())]);
+}
+
 #[test]
 fn test_debugging_options_tracking_hash() {
     let reference = Options::default();
@@ -465,7 +470,7 @@ fn test_debugging_options_tracking_hash() {
         ($name: ident, $non_default_value: expr) => {
             assert_ne!(opts.debugging_opts.$name, $non_default_value);
             opts.debugging_opts.$name = $non_default_value;
-            assert_eq!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+            assert_same_hash(&reference, &opts);
         };
     }
 
@@ -537,7 +542,7 @@ fn test_debugging_options_tracking_hash() {
             opts = reference.clone();
             assert_ne!(opts.debugging_opts.$name, $non_default_value);
             opts.debugging_opts.$name = $non_default_value;
-            assert_ne!(reference.dep_tracking_hash(), opts.dep_tracking_hash());
+            assert_different_hash(&reference, &opts);
         };
     }
 

compiler/rustc_middle/src/hir/map/mod.rs

@@ -943,7 +943,7 @@ pub(super) fn index_hir<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> &'tcx Indexe
         intravisit::walk_crate(&mut collector, tcx.untracked_crate);
 
         let crate_disambiguator = tcx.sess.local_crate_disambiguator();
-        let cmdline_args = tcx.sess.opts.dep_tracking_hash();
+        let cmdline_args = tcx.sess.opts.dep_tracking_hash(true);
         collector.finalize_and_compute_crate_hash(crate_disambiguator, &*tcx.cstore, cmdline_args)
     };
 

compiler/rustc_session/src/config.rs

@@ -2374,6 +2374,7 @@ crate mod dep_tracking {
 
     impl_dep_tracking_hash_for_sortable_vec_of!(String);
     impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
+    impl_dep_tracking_hash_for_sortable_vec_of!((PathBuf, PathBuf));
     impl_dep_tracking_hash_for_sortable_vec_of!(CrateType);
     impl_dep_tracking_hash_for_sortable_vec_of!((String, lint::Level));
     impl_dep_tracking_hash_for_sortable_vec_of!((String, Option<String>, NativeLibKind));