Lib.rs

The SystemVerilog implementation of the moore compiler.

This crate implements a query-based compiler for the SystemVerilog language. It strives to be a complete implementation of IEEE 1800-2017, mapping any input source text to the equivalent LLHD code.

The implementation uses different representations of the source text for different parts of the compilation. Such a scheme is necessary due to the very messy nature of SystemVerilog, with its strange mixture of static and dynamic typing. Although the compiler uses queries to be able to handle the more involved and loopy dependencies, the representations form a rough chain of processing that each construct flows through (albeit each at its own pace):

• AST: Abstract Syntax Tree emitted by the parser in the syntax crate.
• RST: Resolved Syntax Tree which has ambiguities in the grammar resolved. This is possible by building name resolution scopes and defs on the AST representation, and resolving names to disambiguate things in the grammar.
• HIR: The High-level Intermediate Representation, which does things like taking the list of constructs in a module body and separating them into lists of declarations, instances, parameters, etc. Also tries to get rid of syntactic sugar where appropriate. Type-checking is performed on this representation, and ParamEnv is used to represent different parametrizations of the same HIR module/interface.
• MIR: The Medium-level Intermediate Representation, which has all implicit casting operations and parametrizations made explicit and fully unrolled. At this point most SystemVerilog craziness has been resolved and the nodes are crisp and have a clean, fully checked type.
• LLHD: The Low-level Hardware Description, emitted as the final step during code generation.