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Auto merge of #82285 - nhwn:nonzero-debug, r=nagisa

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Use u32 over Option<u32> in DebugLoc

~~Changes `Option<u32>` fields in `DebugLoc` to `Option<NonZeroU32>`. Since the respective fields (`line` and `col`) are guaranteed to be 1-based, this layout optimization is a freebie.~~

EDIT: Changes `Option<u32>` fields in `DebugLoc` to `u32`. As `@bugadani` pointed out, an `Option<NonZeroU32>` is probably an unnecessary layer of abstraction since the `None` variant is always used as `UNKNOWN_LINE_NUMBER` (which is just `0`).  Also, `SourceInfo` in `metadata.rs` already uses a `u32` instead of an `Option<u32>` to encode the same information, so I think this change is warranted.

Since `@jyn514` raised some concerns over measuring performance in a similar PR (#82255), does this need a perf run?
This commit is contained in:
bors 2021-03-07 20:23:23 +00:00
commit 234781afe3
3 changed files with 15 additions and 25 deletions
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25
compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
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@ -224,9 +224,9 @@ pub struct DebugLoc {
/// Information about the original source file.
pub file: Lrc<SourceFile>,
/// The (1-based) line number.
pub line: Option<u32>,
pub line: u32,
/// The (1-based) column number.
pub col: Option<u32>,
pub col: u32,
}
impl CodegenCx<'ll, '_> {
@ -243,16 +243,16 @@ impl CodegenCx<'ll, '_> {
let line = (line + 1) as u32;
let col = (pos - line_pos).to_u32() + 1;
(file, Some(line), Some(col))
(file, line, col)
}
Err(file) => (file, None, None),
Err(file) => (file, UNKNOWN_LINE_NUMBER, UNKNOWN_COLUMN_NUMBER),
};
// For MSVC, omit the column number.
// Otherwise, emit it. This mimics clang behaviour.
// See discussion in https://github.com/rust-lang/rust/issues/42921
if self.sess().target.is_like_msvc {
DebugLoc { file, line, col: None }
DebugLoc { file, line, col: UNKNOWN_COLUMN_NUMBER }
} else {
DebugLoc { file, line, col }
}
@ -358,9 +358,9 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
linkage_name.as_ptr().cast(),
linkage_name.len(),
file_metadata,
loc.line.unwrap_or(UNKNOWN_LINE_NUMBER),
loc.line,
function_type_metadata,
scope_line.unwrap_or(UNKNOWN_LINE_NUMBER),
scope_line,
flags,
spflags,
maybe_definition_llfn,
@ -550,14 +550,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
) -> &'ll DILocation {
let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo());
unsafe {
llvm::LLVMRustDIBuilderCreateDebugLocation(
line.unwrap_or(UNKNOWN_LINE_NUMBER),
col.unwrap_or(UNKNOWN_COLUMN_NUMBER),
scope,
inlined_at,
)
}
unsafe { llvm::LLVMRustDIBuilderCreateDebugLocation(line, col, scope, inlined_at) }
}
fn create_vtable_metadata(&self, ty: Ty<'tcx>, vtable: Self::Value) {
@ -606,7 +599,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
name.as_ptr().cast(),
name.len(),
file_metadata,
loc.line.unwrap_or(UNKNOWN_LINE_NUMBER),
loc.line,
type_metadata,
true,
DIFlags::FlagZero,