Rust Compiler References: HIR, Type Inference, MIR, Borrow Check, Optimization, and Code Generation

- [Entry point for macro fragments][parse_nonterminal] - `AST` definition: [`rustc_ast`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/index.html) - Feature gating: **TODO** - Early linting: **TODO** - The High Level Intermediate Representation (HIR) - Guide: [The HIR](hir.md) - Guide: [Identifiers in the HIR](hir.md#identifiers-in-the-hir) - Guide: [The `HIR` Map](hir.md#the-hir-map) - Guide: [Lowering `AST` to `HIR`](ast-lowering.md) - How to view `HIR` representation for your code `cargo rustc -- -Z unpretty=hir-tree` - Rustc `HIR` definition: [`rustc_hir`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/index.html) - Main entry point: **TODO** - Late linting: **TODO** - Type Inference - Guide: [Type Inference](type-inference.md) - Guide: [The ty Module: Representing Types](ty.md) (semantics) - Main entry point (type inference): [`InferCtxtBuilder::enter`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_infer/infer/struct.InferCtxtBuilder.html#method.enter) - Main entry point (type checking bodies): [the `typeck` query](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.TyCtxt.html#method.typeck) - These two functions can't be decoupled. - The Mid Level Intermediate Representation (MIR) - Guide: [The `MIR` (Mid level IR)](mir/index.md) - Definition: [`rustc_middle/src/mir`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/mir/index.html) - Definition of sources that manipulates the MIR: [`rustc_mir_build`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_build/index.html), [`rustc_mir_dataflow`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_dataflow/index.html), [`rustc_mir_transform`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_transform/index.html) - The Borrow Checker - Guide: [MIR Borrow Check](borrow_check.md) - Definition: [`rustc_borrowck`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_borrowck/index.html) - Main entry point: [`mir_borrowck` query](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_borrowck/fn.mir_borrowck.html) - `MIR` Optimizations - Guide: [MIR Optimizations](mir/optimizations.md) - Definition: [`rustc_mir_transform`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_transform/index.html) - Main entry point: [`optimized_mir` query](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir_transform/fn.optimized_mir.html) - Code Generation - Guide: [Code Generation](backend/codegen.md) - Generating Machine Code from `LLVM-IR` with LLVM - **TODO: reference?** - Main entry point: [`rustc_codegen_ssa::base::codegen_crate`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/base/fn.codegen_crate.html) - This monomorphizes and produces `LLVM-IR` for one codegen unit. It then starts a background thread to run LLVM, which must be joined later. - Monomorphization happens lazily via [`FunctionCx::monomorphize`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/mir/struct.FunctionCx.html#method.monomorphize) and [`rustc_codegen_ssa::base::codegen_instance `](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/base/fn.codegen_instance.html)

This section provides references for several key stages in the Rust compilation process, including the High-Level Intermediate Representation (HIR), type inference and checking, the Mid-Level Intermediate Representation (MIR), the borrow checker, MIR optimizations, and code generation. Each stage includes links to relevant guides, definitions, and main entry points in the `rustc` codebase.