From bba2a1e07179c59b422e60411813446606b1b7f3 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Sat, 29 Apr 2023 12:01:13 +0100
Subject: [PATCH] Fix spans in LLVM-generated inline asm errors
Previously, incorrect spans were reported if inline assembly contained
CRLF (Windows) line endings.
Fixes #110885
---
compiler/rustc_codegen_ssa/src/back/write.rs | 12 ++++++++---
compiler/rustc_span/src/lib.rs | 22 ++++++++++++++++++++
2 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index c80347448cbb2..d0bed71bd12a5 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -1821,9 +1821,15 @@ impl SharedEmitterMain {
let source = sess
.source_map()
.new_source_file(FileName::inline_asm_source_code(&buffer), buffer);
- let source_span = Span::with_root_ctxt(source.start_pos, source.end_pos);
- let spans: Vec<_> =
- spans.iter().map(|sp| source_span.from_inner(*sp)).collect();
+ let spans: Vec<_> = spans
+ .iter()
+ .map(|sp| {
+ Span::with_root_ctxt(
+ source.normalized_byte_pos(sp.start as u32),
+ source.normalized_byte_pos(sp.end as u32),
+ )
+ })
+ .collect();
err.span_note(spans, "instantiated into assembly here");
}
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 8a900ca427ebe..fa89992f79a1f 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -1745,6 +1745,28 @@ impl SourceFile {
BytePos::from_u32(pos.0 - self.start_pos.0 + diff)
}
+ /// Calculates a normalized byte position from a byte offset relative to the
+ /// start of the file.
+ ///
+ /// When we get an inline assembler error from LLVM during codegen, we
+ /// import the expanded assembly code as a new `SourceFile`, which can then
+ /// be used for error reporting with spans. However the byte offsets given
+ /// to us by LLVM are relative to the start of the original buffer, not the
+ /// normalized one. Hence we need to convert those offsets to the normalized
+ /// form when constructing spans.
+ pub fn normalized_byte_pos(&self, offset: u32) -> BytePos {
+ let diff = match self
+ .normalized_pos
+ .binary_search_by(|np| (np.pos.0 + np.diff).cmp(&(self.start_pos.0 + offset)))
+ {
+ Ok(i) => self.normalized_pos[i].diff,
+ Err(i) if i == 0 => 0,
+ Err(i) => self.normalized_pos[i - 1].diff,
+ };
+
+ BytePos::from_u32(self.start_pos.0 + offset - diff)
+ }
+
/// Converts an absolute `BytePos` to a `CharPos` relative to the `SourceFile`.
pub fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos {
// The number of extra bytes due to multibyte chars in the `SourceFile`.