bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Responded to all feedback as of 2020-10-30

Browse source
This commit is contained in:
Rich Kadel 2020-10-30 16:09:05 -07:00
parent 1973f84ebb
commit a7d956583c
9 changed files with 367 additions and 208 deletions
Download patch file Download diff file Expand all files Collapse all files

24
compiler/rustc_mir/src/transform/coverage/spans.rs
View file

@ -656,7 +656,9 @@ fn filtered_statement_span(statement: &'a Statement<'tcx>, body_span: Span) -> O
// Ignore `Nop`s
| StatementKind::Nop => None,
// FIXME(richkadel): Look into a possible issue assigning the span to a
// FIXME(#78546): MIR InstrumentCoverage - Can the source_info.span for `FakeRead`
// statements be more consistent?
//
// FakeReadCause::ForGuardBinding, in this example:
// match somenum {
// x if x < 1 => { ... }
@ -669,15 +671,7 @@ fn filtered_statement_span(statement: &'a Statement<'tcx>, body_span: Span) -> O
// _4 = &_1; (at the span for the first `x`)
// and `_1` is the `Place` for `somenum`.
//
// The arm code BasicBlock already has its own assignment for `x` itself, `_3 = 1`, and I've
// decided it's reasonable for that span (even though outside the arm code) to be part of
// the counted coverage of the arm code execution, but I can't justify including the literal
// `1` in the arm code. I'm pretty sure that, if the `FakeRead(ForGuardBinding)` has a
// purpose in codegen, it's probably in the right BasicBlock, but if so, the `Statement`s
// `source_info.span` can't be right.
//
// Consider correcting the span assignment, assuming there is a better solution, and see if
// the following pattern can be removed here:
// If and when the Issue is resolved, remove this special case match pattern:
StatementKind::FakeRead(cause, _) if cause == FakeReadCause::ForGuardBinding => None,
// Retain spans from all other statements
@ -710,13 +704,7 @@ fn filtered_terminator_span(terminator: &'a Terminator<'tcx>, body_span: Span) -
// `FalseEdge`.
| TerminatorKind::FalseEdge { .. } => None,
// FIXME(richkadel): Note that `Goto` was initially filtered out (by returning `None`, as
// with the `TerminatorKind`s above) because its `Span` was way to broad to be beneficial,
// and, at the time, `Goto` didn't seem to provide any additional contributions to the
// coverage analysis. Upon further review, `Goto` terminated blocks do appear to benefit
// the coverage analysis, and the BCB CFG. To overcome the issues with the `Spans`, the
// coverage algorithms--and the final coverage map generation--include some exceptional
// behaviors.
// FIXME(#78542): Can spans for `TerminatorKind::Goto` be improved to avoid special cases?
//
// `Goto`s are often the targets of `SwitchInt` branches, and certain important
// optimizations to replace some `Counter`s with `Expression`s require a separate
@ -750,7 +738,7 @@ fn filtered_terminator_span(terminator: &'a Terminator<'tcx>, body_span: Span) -
}
}
#[inline(always)]
#[inline]
fn function_source_span(span: Span, body_span: Span) -> Span {
let span = original_sp(span, body_span).with_ctxt(SyntaxContext::root());
if body_span.contains(span) { span } else { body_span }