From b3067494e8a53f0d4151357b00a4ebc42f043121 Mon Sep 17 00:00:00 2001
From: Eduard-Mihai Burtescu <eddyb@lyken.rs>
Date: Tue, 18 Apr 2023 04:01:09 +0300
Subject: [PATCH] decorations: limit zombie `SerializedSpan`s to an `OpLine`
 equivalent.

---
 crates/rustc_codegen_spirv/src/decorations.rs | 20 +++++++------------
 tests/ui/dis/ptr_copy.normal.stderr           |  2 +-
 .../consts/nested-ref-in-composite.stderr     |  4 ++--
 3 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/crates/rustc_codegen_spirv/src/decorations.rs b/crates/rustc_codegen_spirv/src/decorations.rs
index 2a317ecc7a..322d3067dc 100644
--- a/crates/rustc_codegen_spirv/src/decorations.rs
+++ b/crates/rustc_codegen_spirv/src/decorations.rs
@@ -139,8 +139,9 @@ impl CustomDecoration for ZombieDecoration {
 #[derive(Deserialize, Serialize)]
 pub struct SerializedSpan {
     file_name: String,
+    // NOTE(eddyb) by keeping `lo` but not `hi`, we mimick `OpLine` limitations
+    // (which could be lifted in the future using custom SPIR-T debuginfo).
     lo: u32,
-    hi: u32,
 }
 
 impl SerializedSpan {
@@ -151,14 +152,10 @@ impl SerializedSpan {
             return None;
         }
 
-        let (lo, hi) = (span.lo(), span.hi());
-        if lo > hi {
-            // FIXME(eddyb) broken `Span` - potentially turn this into an assert?
-            return None;
-        }
+        let lo = span.lo();
 
         let file = builder.source_map.lookup_source_file(lo);
-        if !(file.start_pos <= lo && hi <= file.end_pos) {
+        if !(file.start_pos..=file.end_pos).contains(&lo) {
             // FIXME(eddyb) broken `Span` - potentially turn this into an assert?
             return None;
         }
@@ -169,7 +166,6 @@ impl SerializedSpan {
         Some(Self {
             file_name: file.name.prefer_remapped().to_string(),
             lo: (lo - file.start_pos).to_u32(),
-            hi: (hi - file.start_pos).to_u32(),
         })
     }
 }
@@ -296,11 +292,9 @@ impl<'a> SpanRegenerator<'a> {
 
         // Sanity check - assuming `SerializedSpan` isn't corrupted, this assert
         // could only ever fail because of the file name being ambiguous.
-        assert!(span.lo <= span.hi && span.hi <= (file.end_pos.0 - file.start_pos.0));
+        assert!(span.lo <= (file.end_pos.0 - file.start_pos.0));
 
-        Some(Span::with_root_ctxt(
-            file.start_pos + Pos::from_u32(span.lo),
-            file.start_pos + Pos::from_u32(span.hi),
-        ))
+        let lo = file.start_pos + Pos::from_u32(span.lo);
+        Some(Span::with_root_ctxt(lo, lo))
     }
 }
diff --git a/tests/ui/dis/ptr_copy.normal.stderr b/tests/ui/dis/ptr_copy.normal.stderr
index c9f66e2d67..2e27465411 100644
--- a/tests/ui/dis/ptr_copy.normal.stderr
+++ b/tests/ui/dis/ptr_copy.normal.stderr
@@ -2,7 +2,7 @@ error: Cannot memcpy dynamically sized data
     --> $CORE_SRC/intrinsics.rs:2460:9
      |
 2460 |         copy(src, dst, count)
-     |         ^^^^^^^^^^^^^^^^^^^^^
+     |         ^
      |
      = note: Stack:
              core::intrinsics::copy::<f32>
diff --git a/tests/ui/lang/consts/nested-ref-in-composite.stderr b/tests/ui/lang/consts/nested-ref-in-composite.stderr
index 0844de7a6b..9f5c2a7aba 100644
--- a/tests/ui/lang/consts/nested-ref-in-composite.stderr
+++ b/tests/ui/lang/consts/nested-ref-in-composite.stderr
@@ -2,7 +2,7 @@ error: constant arrays/structs cannot contain pointers to other constants
   --> $DIR/nested-ref-in-composite.rs:20:17
    |
 20 |     *pair_out = pair_deep_load(&(&123, &3.14));
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                 ^
    |
    = note: Stack:
            nested_ref_in_composite::main_pair
@@ -12,7 +12,7 @@ error: constant arrays/structs cannot contain pointers to other constants
   --> $DIR/nested-ref-in-composite.rs:25:19
    |
 25 |     *array3_out = array3_deep_load(&[&0, &1, &2]);
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                   ^
    |
    = note: Stack:
            nested_ref_in_composite::main_array3