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MCDC coverage: support nested decision coverage #123409 provided the initial MCDC coverage implementation. As referenced in #124144, it does not currently support "nested" decisions, like the following example : ```rust fn nested_if_in_condition(a: bool, b: bool, c: bool) { if a && if b || c { true } else { false } { say("yes"); } else { say("no"); } } ``` Note that there is an if-expression (`if b || c ...`) embedded inside a boolean expression in the decision of an outer if-expression. This PR proposes a workaround for this cases, by introducing a Decision context stack, and by handing several `temporary condition bitmaps` instead of just one. When instrumenting boolean expressions, if the current node is a leaf condition (i.e. not a `||`/`&&` logical operator nor a `!` not operator), we insert a new decision context, such that if there are more boolean expressions inside the condition, they are handled as separate expressions. On the codegen LLVM side, we allocate as many `temp_cond_bitmap`s as necessary to handle the maximum encountered decision depth. |
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| Cargo.toml | ||
| messages.ftl | ||
| README.md | ||
The codegen crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc dev guide.