rust/compiler/rustc_data_structures
bors a1dfd2490a Auto merge of #77080 - richkadel:llvm-coverage-counters-2, r=tmandry
Working branch-level code coverage

Add a generalized implementation for computing branch-level coverage spans.

This iteration resolves some of the challenges I had identified a few weeks ago.

I've tried to implement a solution that is general enough to work for a lot of different graphs/patterns. It's encouraging to see the results on fairly large and complex crates seem to meet my expectations. This may be a "functionally complete" implementation.

Except for bug fixes or edge cases I haven't run into yet, the next and essentially final step, I think, is to replace some Counters with CounterExpressions (where their counter values can be computed by adding or subtracting other counters/expressions).

Examples of branch-level coverage support enabled in this PR:

* https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-cov-reports-base/expected_show_coverage.coverage_of_drop_trait.txt
* https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-cov-reports-base/expected_show_coverage.coverage_of_if.txt
* https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-cov-reports-base/expected_show_coverage.coverage_of_if_else.txt
* https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-cov-reports-base/expected_show_coverage.coverage_of_simple_loop.txt
* https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-cov-reports-base/expected_show_coverage.coverage_of_simple_match.txt
* ... _and others in the same directory_

Examples of coverage analysis results (MIR spanview files) used to inject counters in the right `BasicBlocks`:

* https://htmlpreview.github.io/?https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-mir-cov-html-base/expected_mir_dump.coverage_of_drop_trait/coverage_of_drop_trait.main.-------.InstrumentCoverage.0.html
* https://htmlpreview.github.io/?https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-mir-cov-html-base/expected_mir_dump.coverage_of_if/coverage_of_if.main.-------.InstrumentCoverage.0.html
* https://htmlpreview.github.io/?https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-mir-cov-html-base/expected_mir_dump.coverage_of_if_else/coverage_of_if_else.main.-------.InstrumentCoverage.0.html
* https://htmlpreview.github.io/?https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-mir-cov-html-base/expected_mir_dump.coverage_of_simple_loop/coverage_of_simple_loop.main.-------.InstrumentCoverage.0.html
* https://htmlpreview.github.io/?https://github.com/richkadel/rust/blob/llvm-coverage-counters-2/src/test/run-make-fulldeps/instrument-coverage-mir-cov-html-base/expected_mir_dump.coverage_of_simple_match/coverage_of_simple_match.main.-------.InstrumentCoverage.0.html
* ... _and others in the same directory_

Here is some sample coverage output after compiling a few real-world crates with the new branch-level coverage features:

<img width="801" alt="Screen Shot 2020-09-25 at 1 03 11 PM" src="https://user-images.githubusercontent.com/3827298/94316848-fd882c00-ff39-11ea-9cff-0402d3abd1e7.png">
<img width="721" alt="Screen Shot 2020-09-25 at 1 00 36 PM" src="https://user-images.githubusercontent.com/3827298/94316886-11cc2900-ff3a-11ea-9d03-80b26c8a5173.png">
<img width="889" alt="Screen Shot 2020-09-25 at 12 54 57 PM" src="https://user-images.githubusercontent.com/3827298/94316900-18f33700-ff3a-11ea-8a80-58f67d84b8de.png">

r? `@tmandry`
FYI: `@wesleywiser`
2020-10-05 19:34:44 +00:00
..
src Auto merge of #77080 - richkadel:llvm-coverage-counters-2, r=tmandry 2020-10-05 19:34:44 +00:00
Cargo.toml Auto merge of #76928 - lcnr:opaque-types-cache, r=tmandry 2020-09-22 22:52:07 +00:00