diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs | 124 | 
1 files changed, 0 insertions, 124 deletions
| diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs deleted file mode 100644 index 4a7721879fd..00000000000 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen/spans.rs +++ /dev/null @@ -1,124 +0,0 @@ -use rustc_middle::mir::coverage::FunctionCoverageInfo; -use rustc_span::source_map::SourceMap; -use rustc_span::{BytePos, Pos, SourceFile, Span}; -use tracing::debug; - -use crate::coverageinfo::ffi; -use crate::coverageinfo::mapgen::LocalFileId; - -/// Converts the span into its start line and column, and end line and column. -/// -/// Line numbers and column numbers are 1-based. Unlike most column numbers emitted by -/// the compiler, these column numbers are denoted in **bytes**, because that's what -/// LLVM's `llvm-cov` tool expects to see in coverage maps. -/// -/// Returns `None` if the conversion failed for some reason. This shouldn't happen, -/// but it's hard to rule out entirely (especially in the presence of complex macros -/// or other expansions), and if it does happen then skipping a span or function is -/// better than an ICE or `llvm-cov` failure that the user might have no way to avoid. -pub(crate) fn make_coverage_span( - file_id: LocalFileId, - source_map: &SourceMap, - fn_cov_info: &FunctionCoverageInfo, - file: &SourceFile, - span: Span, -) -> Option<ffi::CoverageSpan> { - let span = ensure_non_empty_span(source_map, fn_cov_info, span)?; - - let lo = span.lo(); - let hi = span.hi(); - - // Column numbers need to be in bytes, so we can't use the more convenient - // `SourceMap` methods for looking up file coordinates. - let line_and_byte_column = |pos: BytePos| -> Option<(usize, usize)> { - let rpos = file.relative_position(pos); - let line_index = file.lookup_line(rpos)?; - let line_start = file.lines()[line_index]; - // Line numbers and column numbers are 1-based, so add 1 to each. - Some((line_index + 1, (rpos - line_start).to_usize() + 1)) - }; - - let (mut start_line, start_col) = line_and_byte_column(lo)?; - let (mut end_line, end_col) = line_and_byte_column(hi)?; - - // Apply an offset so that code in doctests has correct line numbers. - // FIXME(#79417): Currently we have no way to offset doctest _columns_. - start_line = source_map.doctest_offset_line(&file.name, start_line); - end_line = source_map.doctest_offset_line(&file.name, end_line); - - check_coverage_span(ffi::CoverageSpan { - file_id: file_id.as_u32(), - start_line: start_line as u32, - start_col: start_col as u32, - end_line: end_line as u32, - end_col: end_col as u32, - }) -} - -fn ensure_non_empty_span( - source_map: &SourceMap, - fn_cov_info: &FunctionCoverageInfo, - span: Span, -) -> Option<Span> { - if !span.is_empty() { - return Some(span); - } - - let lo = span.lo(); - let hi = span.hi(); - - // The span is empty, so try to expand it to cover an adjacent '{' or '}', - // but only within the bounds of the body span. - let try_next = hi < fn_cov_info.body_span.hi(); - let try_prev = fn_cov_info.body_span.lo() < lo; - if !(try_next || try_prev) { - return None; - } - - source_map - .span_to_source(span, |src, start, end| try { - // We're only checking for specific ASCII characters, so we don't - // have to worry about multi-byte code points. - if try_next && src.as_bytes()[end] == b'{' { - Some(span.with_hi(hi + BytePos(1))) - } else if try_prev && src.as_bytes()[start - 1] == b'}' { - Some(span.with_lo(lo - BytePos(1))) - } else { - None - } - }) - .ok()? -} - -/// If `llvm-cov` sees a source region that is improperly ordered (end < start), -/// it will immediately exit with a fatal error. To prevent that from happening, -/// discard regions that are improperly ordered, or might be interpreted in a -/// way that makes them improperly ordered. -fn check_coverage_span(cov_span: ffi::CoverageSpan) -> Option<ffi::CoverageSpan> { - let ffi::CoverageSpan { file_id: _, start_line, start_col, end_line, end_col } = cov_span; - - // Line/column coordinates are supposed to be 1-based. If we ever emit - // coordinates of 0, `llvm-cov` might misinterpret them. - let all_nonzero = [start_line, start_col, end_line, end_col].into_iter().all(|x| x != 0); - // Coverage mappings use the high bit of `end_col` to indicate that a - // region is actually a "gap" region, so make sure it's unset. - let end_col_has_high_bit_unset = (end_col & (1 << 31)) == 0; - // If a region is improperly ordered (end < start), `llvm-cov` will exit - // with a fatal error, which is inconvenient for users and hard to debug. - let is_ordered = (start_line, start_col) <= (end_line, end_col); - - if all_nonzero && end_col_has_high_bit_unset && is_ordered { - Some(cov_span) - } else { - debug!( - ?cov_span, - ?all_nonzero, - ?end_col_has_high_bit_unset, - ?is_ordered, - "Skipping source region that would be misinterpreted or rejected by LLVM" - ); - // If this happens in a debug build, ICE to make it easier to notice. - debug_assert!(false, "Improper source region: {cov_span:?}"); - None - } -} | 
