From Newsgroup: comp.compilers
How GCC tries to test all the code paths efficiently.
Abstract
We describe the implementation of the prime path coverage support
introduced the GNU Compiler Collection 15, a structural coverage metric
that focuses on paths of execution through the program. Prime path
coverage strikes a good balance between the number of tests and coverage,
and requires that loops are taken, taken more than once, and skipped. We
show that prime path coverage subsumes modified condition/decision
coverage (MC/DC). We improve on the current state-of-the-art algorithms
for enumerating prime paths by using a suffix tree for efficient pruning
of duplicated and redundant subpaths, reducing it to O(n2m) from O(n2m2),
where n is the length of the longest path and m is the number of candidate paths. We can efficiently track candidate paths using a few bitwise
operations based on a compact representation of the indices of the ordered prime paths. By analyzing the control flow graph, GCC can observe and instrument paths in a language-agnostic manner, and accurately report what
code must be run in what order to achieve coverage.
https://arxiv.org/abs/2505.14694
Regards,
John Levine,
johnl@taugh.com, Taughannock Networks, Trumansburg NY
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https://jl.ly
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