Auto merge of #45867 - michaelwoerister:check-ich-stability, r=nikomatsakis

incr.comp.: Verify stability of incr. comp. hashes and clean up various other things.

The main contribution of this PR is that it adds the `-Z incremental-verify-ich` functionality. Normally, when the red-green tracking system determines that a certain query result has not changed, it does not re-compute the incr. comp. hash (ICH) for that query result because that hash is already known. `-Z incremental-verify-ich` tells the compiler to re-hash the query result and compare the new hash against the cached hash. This is a rather thorough way of
- testing hashing implementation stability,
- finding missing `[input]` annotations on `DepNodes`, and
- finding missing read-edges,

since both a missed read and a missing `[input]` annotation can lead to something being marked as green instead of red and thus will have a different hash than it should have.

Case in point, implementing this verification logic and activating it for all `src/test/incremental` tests has revealed several such oversights, all of which are fixed in this PR.

r? @nikomatsakis

1 files changed, 37 insertions, 2 deletions

diff --git a/src/test/incremental/hashes/panic_exprs.rs b/src/test/incremental/hashes/panic_exprs.rs
index 5d4d434fd63..4a3e4bc49ce 100644
--- a/src/test/incremental/hashes/panic_exprs.rs
+++ b/src/test/incremental/hashes/panic_exprs.rs
@@ -152,13 +152,48 @@ pub fn mod_by_zero(val: i32) -> i32 {
 }
 
 
+// shift left ------------------------------------------------------------------
+#[cfg(cfail1)]
+pub fn shift_left(val: i32, shift: usize) -> i32 {
+    val << shift
+}
+
+#[cfg(not(cfail1))]
+#[rustc_clean(label="Hir", cfg="cfail2")]
+#[rustc_clean(label="Hir", cfg="cfail3")]
+#[rustc_dirty(label="HirBody", cfg="cfail2")]
+#[rustc_clean(label="HirBody", cfg="cfail3")]
+#[rustc_metadata_clean(cfg="cfail2")]
+#[rustc_metadata_clean(cfg="cfail3")]
+pub fn shift_left(val: i32, shift: usize) -> i32 {
+    val << shift
+}
+
+
+// shift right ------------------------------------------------------------------
+#[cfg(cfail1)]
+pub fn shift_right(val: i32, shift: usize) -> i32 {
+    val >> shift
+}
+
+#[cfg(not(cfail1))]
+#[rustc_clean(label="Hir", cfg="cfail2")]
+#[rustc_clean(label="Hir", cfg="cfail3")]
+#[rustc_dirty(label="HirBody", cfg="cfail2")]
+#[rustc_clean(label="HirBody", cfg="cfail3")]
+#[rustc_metadata_clean(cfg="cfail2")]
+#[rustc_metadata_clean(cfg="cfail3")]
+pub fn shift_right(val: i32, shift: usize) -> i32 {
+    val >> shift
+}
+
 
 // THE FOLLOWING ITEMS SHOULD NOT BE INFLUENCED BY THEIR SOURCE LOCATION
 
 // bitwise ---------------------------------------------------------------------
 #[cfg(cfail1)]
 pub fn bitwise(val: i32) -> i32 {
-    !val & 0x101010101 | 0x45689 ^ 0x2372382 << 1 >> 1
+    !val & 0x101010101 | 0x45689 ^ 0x2372382
 }
 
 #[cfg(not(cfail1))]
@@ -169,7 +204,7 @@ pub fn bitwise(val: i32) -> i32 {
 #[rustc_metadata_clean(cfg="cfail2")]
 #[rustc_metadata_clean(cfg="cfail3")]
 pub fn bitwise(val: i32) -> i32 {
-    !val & 0x101010101 | 0x45689 ^ 0x2372382 << 1 >> 1
+    !val & 0x101010101 | 0x45689 ^ 0x2372382
 }