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Diffstat (limited to 'tests/run-coverage/overflow.coverage')
| -rw-r--r-- | tests/run-coverage/overflow.coverage | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/tests/run-coverage/overflow.coverage b/tests/run-coverage/overflow.coverage new file mode 100644 index 000000000..950437591 --- /dev/null +++ b/tests/run-coverage/overflow.coverage @@ -0,0 +1,64 @@ + 1| |#![allow(unused_assignments)] + 2| |// failure-status: 101 + 3| | + 4| 4|fn might_overflow(to_add: u32) -> u32 { + 5| 4| if to_add > 5 { + 6| 1| println!("this will probably overflow"); + 7| 3| } + 8| 4| let add_to = u32::MAX - 5; + 9| 4| println!("does {} + {} overflow?", add_to, to_add); + 10| 4| let result = to_add + add_to; + 11| 4| println!("continuing after overflow check"); + 12| 4| result + 13| 4|} + 14| | + 15| 1|fn main() -> Result<(),u8> { + 16| 1| let mut countdown = 10; + 17| 11| while countdown > 0 { + 18| 11| if countdown == 1 { + 19| 1| let result = might_overflow(10); + 20| 1| println!("Result: {}", result); + 21| 10| } else if countdown < 5 { + 22| 3| let result = might_overflow(1); + 23| 3| println!("Result: {}", result); + 24| 6| } + 25| 10| countdown -= 1; + 26| | } + 27| 0| Ok(()) + 28| 0|} + 29| | + 30| |// Notes: + 31| |// 1. Compare this program and its coverage results to those of the very similar test `assert.rs`, + 32| |// and similar tests `panic_unwind.rs`, abort.rs` and `try_error_result.rs`. + 33| |// 2. This test confirms the coverage generated when a program passes or fails a + 34| |// compiler-generated `TerminatorKind::Assert` (based on an overflow check, in this case). + 35| |// 3. Similar to how the coverage instrumentation handles `TerminatorKind::Call`, + 36| |// compiler-generated assertion failures are assumed to be a symptom of a program bug, not + 37| |// expected behavior. To simplify the coverage graphs and keep instrumented programs as + 38| |// small and fast as possible, `Assert` terminators are assumed to always succeed, and + 39| |// therefore are considered "non-branching" terminators. So, an `Assert` terminator does not + 40| |// get its own coverage counter. + 41| |// 4. After an unhandled panic or failed Assert, coverage results may not always be intuitive. + 42| |// In this test, the final count for the statements after the `if` block in `might_overflow()` + 43| |// is 4, even though the lines after `to_add + add_to` were executed only 3 times. Depending + 44| |// on the MIR graph and the structure of the code, this count could have been 3 (which might + 45| |// have been valid for the overflowed add `+`, but should have been 4 for the lines before + 46| |// the overflow. The reason for this potential uncertainty is, a `CounterKind` is incremented + 47| |// via StatementKind::Counter at the end of the block, but (as in the case in this test), + 48| |// a CounterKind::Expression is always evaluated. In this case, the expression was based on + 49| |// a `Counter` incremented as part of the evaluation of the `if` expression, which was + 50| |// executed, and counted, 4 times, before reaching the overflow add. + 51| | + 52| |// If the program did not overflow, the coverage for `might_overflow()` would look like this: + 53| |// + 54| |// 4| |fn might_overflow(to_add: u32) -> u32 { + 55| |// 5| 4| if to_add > 5 { + 56| |// 6| 0| println!("this will probably overflow"); + 57| |// 7| 4| } + 58| |// 8| 4| let add_to = u32::MAX - 5; + 59| |// 9| 4| println!("does {} + {} overflow?", add_to, to_add); + 60| |// 10| 4| let result = to_add + add_to; + 61| |// 11| 4| println!("continuing after overflow check"); + 62| |// 12| 4| result + 63| |// 13| 4|} + |