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Diffstat (limited to 'src/doc/rustc-dev-guide')
| -rw-r--r-- | src/doc/rustc-dev-guide/src/img/dataflow-graphviz-example.png | bin | 0 -> 81892 bytes | |||
| -rw-r--r-- | src/doc/rustc-dev-guide/src/mir/dataflow.md | 16 | ||||
| -rw-r--r-- | src/doc/rustc-dev-guide/src/mir/debugging.md | 4 |
3 files changed, 20 insertions, 0 deletions
diff --git a/src/doc/rustc-dev-guide/src/img/dataflow-graphviz-example.png b/src/doc/rustc-dev-guide/src/img/dataflow-graphviz-example.png new file mode 100644 index 00000000000..718411a8c42 --- /dev/null +++ b/src/doc/rustc-dev-guide/src/img/dataflow-graphviz-example.png Binary files differdiff --git a/src/doc/rustc-dev-guide/src/mir/dataflow.md b/src/doc/rustc-dev-guide/src/mir/dataflow.md index 5b10afec1f3..be8d4fb9886 100644 --- a/src/doc/rustc-dev-guide/src/mir/dataflow.md +++ b/src/doc/rustc-dev-guide/src/mir/dataflow.md @@ -154,8 +154,24 @@ for (bb, block) in body.basic_blocks().iter_enumerated() { } ``` +### Graphviz Diagrams + +When the results of a dataflow analysis are not what you expect, it often helps +to visualize them. This can be done with the `-Zdump-mir` flags described in +[Debugging MIR]. Start with `-Zdump-mir=F -Zdump-mir-dataflow`, where `F` is +either "all" or the name of the MIR body you are interested in. + +These `.dot` files will be saved in your `mir_dump` directory and will have the +`NAME` of the analysis (e.g. `maybe_inits`) as part of their filename. Each +visualization will display the full dataflow state at entry and exit of each +block, as well as any changes that occur in each statement and terminator. See +the example below: + + + ["gen-kill" problems]: https://en.wikipedia.org/wiki/Data-flow_analysis#Bit_vector_problems [*Static Program Analysis*]: https://cs.au.dk/~amoeller/spa/ +[Debugging MIR]: ./debugging.html [`AnalysisDomain`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/dataflow/trait.AnalysisDomain.html [`Analysis`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/dataflow/trait.Analysis.html [`Engine`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/dataflow/struct.Engine.html diff --git a/src/doc/rustc-dev-guide/src/mir/debugging.md b/src/doc/rustc-dev-guide/src/mir/debugging.md index edb68ca7202..3a47a575d59 100644 --- a/src/doc/rustc-dev-guide/src/mir/debugging.md +++ b/src/doc/rustc-dev-guide/src/mir/debugging.md @@ -6,6 +6,8 @@ additional output formats, including: * `-Zdump-mir-graphviz` - dumps a `.dot` file that represents MIR as a control-flow graph +* `-Zdump-mir-dataflow` - dumps a `.dot` file showing the [dataflow state] at + each point in the control-flow graph * `-Zdump-mir-spanview` - dumps an `.html` file that highlights the source spans associated with MIR elements (including mouse-over actions to reveal elements obscured by overlaps, and tooltips to view the MIR statements). @@ -87,3 +89,5 @@ rustc.main.002-006.NoLandingPads.before.mir that appeared within the `main` function.) TODO: anything else? + +[dataflow state]: ./dataflow.html#graphviz-diagrams |
