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coverage: Add branch coverage support for if-let and let-chains
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Zalathar committed Apr 30, 2024
1 parent c9dd07d commit 7c87ad0
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Showing 4 changed files with 29 additions and 8 deletions.
2 changes: 1 addition & 1 deletion compiler/rustc_mir_build/src/build/coverageinfo.rs
Original file line number Diff line number Diff line change
Expand Up @@ -200,7 +200,7 @@ impl<'tcx> Builder<'_, 'tcx> {
/// If branch coverage is enabled, inject marker statements into `true_block`
/// and `false_block`, and record their IDs in the table of branches.
///
/// Used to instrument let-else for branch coverage.
/// Used to instrument let-else and if-let (including let-chains) for branch coverage.
pub(crate) fn visit_coverage_conditional_let(
&mut self,
pattern: &Pat<'tcx>, // Pattern that has been matched when the true path is taken
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3 changes: 3 additions & 0 deletions compiler/rustc_mir_build/src/build/matches/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1968,6 +1968,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
false,
);

// If branch coverage is enabled, record this branch.
self.visit_coverage_conditional_let(pat, post_guard_block, otherwise_post_guard_block);

post_guard_block.unit()
}

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23 changes: 16 additions & 7 deletions tests/coverage/branch/if-let.cov-map
Original file line number Diff line number Diff line change
@@ -1,13 +1,16 @@
Function name: if_let::if_let
Raw bytes (38): 0x[01, 01, 02, 05, 09, 09, 02, 06, 01, 0c, 01, 01, 10, 02, 03, 11, 00, 12, 05, 00, 16, 00, 1b, 02, 00, 1c, 02, 06, 09, 02, 0c, 02, 06, 07, 03, 05, 01, 02]
Raw bytes (45): 0x[01, 01, 02, 05, 09, 09, 02, 07, 01, 0c, 01, 01, 10, 20, 02, 09, 03, 0c, 00, 13, 02, 00, 11, 00, 12, 05, 00, 16, 00, 1b, 02, 00, 1c, 02, 06, 09, 02, 0c, 02, 06, 07, 03, 05, 01, 02]
Number of files: 1
- file 0 => global file 1
Number of expressions: 2
- expression 0 operands: lhs = Counter(1), rhs = Counter(2)
- expression 1 operands: lhs = Counter(2), rhs = Expression(0, Sub)
Number of file 0 mappings: 6
Number of file 0 mappings: 7
- Code(Counter(0)) at (prev + 12, 1) to (start + 1, 16)
- Code(Expression(0, Sub)) at (prev + 3, 17) to (start + 0, 18)
- Branch { true: Expression(0, Sub), false: Counter(2) } at (prev + 3, 12) to (start + 0, 19)
true = (c1 - c2)
false = c2
- Code(Expression(0, Sub)) at (prev + 0, 17) to (start + 0, 18)
= (c1 - c2)
- Code(Counter(1)) at (prev + 0, 22) to (start + 0, 27)
- Code(Expression(0, Sub)) at (prev + 0, 28) to (start + 2, 6)
Expand All @@ -17,20 +20,26 @@ Number of file 0 mappings: 6
= (c2 + (c1 - c2))

Function name: if_let::if_let_chain
Raw bytes (52): 0x[01, 01, 04, 01, 05, 05, 09, 0f, 0d, 05, 09, 08, 01, 17, 01, 00, 33, 02, 01, 11, 00, 12, 01, 00, 16, 00, 17, 0d, 01, 15, 00, 16, 02, 00, 1a, 00, 1b, 0d, 01, 05, 03, 06, 0f, 03, 0c, 02, 06, 0b, 03, 05, 01, 02]
Raw bytes (66): 0x[01, 01, 04, 01, 05, 05, 09, 0f, 0d, 05, 09, 0a, 01, 17, 01, 00, 33, 20, 02, 05, 01, 0c, 00, 13, 02, 00, 11, 00, 12, 01, 00, 16, 00, 17, 20, 0d, 09, 01, 10, 00, 17, 0d, 00, 15, 00, 16, 02, 00, 1a, 00, 1b, 0d, 01, 05, 03, 06, 0f, 03, 0c, 02, 06, 0b, 03, 05, 01, 02]
Number of files: 1
- file 0 => global file 1
Number of expressions: 4
- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
- expression 1 operands: lhs = Counter(1), rhs = Counter(2)
- expression 2 operands: lhs = Expression(3, Add), rhs = Counter(3)
- expression 3 operands: lhs = Counter(1), rhs = Counter(2)
Number of file 0 mappings: 8
Number of file 0 mappings: 10
- Code(Counter(0)) at (prev + 23, 1) to (start + 0, 51)
- Code(Expression(0, Sub)) at (prev + 1, 17) to (start + 0, 18)
- Branch { true: Expression(0, Sub), false: Counter(1) } at (prev + 1, 12) to (start + 0, 19)
true = (c0 - c1)
false = c1
- Code(Expression(0, Sub)) at (prev + 0, 17) to (start + 0, 18)
= (c0 - c1)
- Code(Counter(0)) at (prev + 0, 22) to (start + 0, 23)
- Code(Counter(3)) at (prev + 1, 21) to (start + 0, 22)
- Branch { true: Counter(3), false: Counter(2) } at (prev + 1, 16) to (start + 0, 23)
true = c3
false = c2
- Code(Counter(3)) at (prev + 0, 21) to (start + 0, 22)
- Code(Expression(0, Sub)) at (prev + 0, 26) to (start + 0, 27)
= (c0 - c1)
- Code(Counter(3)) at (prev + 1, 5) to (start + 3, 6)
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9 changes: 9 additions & 0 deletions tests/coverage/branch/if-let.coverage
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,9 @@
LL| |
LL| 3| if let Some(x) = input {
^2
------------------
| Branch (LL:12): [True: 2, False: 1]
------------------
LL| 2| say(x);
LL| 2| } else {
LL| 1| say("none");
Expand All @@ -24,8 +27,14 @@
LL| 15|fn if_let_chain(a: Option<&str>, b: Option<&str>) {
LL| 15| if let Some(x) = a
^12
------------------
| Branch (LL:12): [True: 12, False: 3]
------------------
LL| 12| && let Some(y) = b
^8
------------------
| Branch (LL:16): [True: 8, False: 4]
------------------
LL| 8| {
LL| 8| say(x);
LL| 8| say(y);
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