diff options
Diffstat (limited to 'src/librustc_codegen_ssa/README.md')
| -rw-r--r-- | src/librustc_codegen_ssa/README.md | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/librustc_codegen_ssa/README.md b/src/librustc_codegen_ssa/README.md index 2178c227956..b7bf0b099e9 100644 --- a/src/librustc_codegen_ssa/README.md +++ b/src/librustc_codegen_ssa/README.md @@ -20,7 +20,7 @@ For these reasons, the separation process involves two transformations that have 1. replace all the LLVM-specific types by generics inside function signatures and structure definitions; 2. encapsulate all functions calling the LLVM FFI inside a set of traits that will define the interface between backend-agnostic code and the backend. -While the LLVM-specific code will be left in `rustc_codegen_llvm`, all the new interfaces and backend-agnostic code will be moved in `rustc_codegen_ssa` (name suggestion by @eddyb). +While the LLVM-specific code will be left in `rustc_codegen_llvm`, all the new traits and backend-agnostic code will be moved in `rustc_codegen_ssa` (name suggestion by @eddyb). ## Generic types and structures @@ -58,7 +58,7 @@ However, the two most important structures `CodegenCx` and `Builder` are not def ## Traits and interface -Because they have to be defined by the backend, `CodegenCx` and `Builder` will be the structures implementing all the traits defining the backend's interface. These traits are defined in the folder `rustc_codegen_ssa/interfaces` and all the backend-agnostic code is parametrized by them. For instance, let us explain how a function in `base.rs` is parametrized: +Because they have to be defined by the backend, `CodegenCx` and `Builder` will be the structures implementing all the traits defining the backend's interface. These traits are defined in the folder `rustc_codegen_ssa/traits` and all the backend-agnostic code is parametrized by them. For instance, let us explain how a function in `base.rs` is parametrized: ```rust pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>( @@ -71,7 +71,7 @@ pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>( In this signature, we have the two lifetime parameters explained earlier and the master type `Bx` which satisfies the trait `BuilderMethods` corresponding to the interface satisfied by the `Builder` struct. The `BuilderMethods` defines an associated type `Bx::CodegenCx` that itself satisfies the `CodegenMethods` traits implemented by the struct `CodegenCx`. -On the trait side, here is an example with part of the definition of `BuilderMethods` in `interfaces/builder.rs`: +On the trait side, here is an example with part of the definition of `BuilderMethods` in `traits/builder.rs`: ```rust pub trait BuilderMethods<'a, 'tcx: 'a>: @@ -116,6 +116,6 @@ However, the current separation between backend-agnostic and LLVM-specific code The `debuginfo` folder has been left almost untouched by the splitting and is specific to LLVM. Only its high-level features have been traitified. -The new `interfaces` folder has 1500 LOC only for trait definitions. Overall, the 27,000 LOC-sized old `rustc_codegen_llvm` code has been split into the new 18,500 LOC-sized new `rustc_codegen_llvm` and the 12,000 LOC-sized `rustc_codegen_ssa`. We can say that this refactoring allowed the reuse of approximately 10,000 LOC that would otherwise have had to be duplicated between the multiple backends of `rustc`. +The new `traits` folder has 1500 LOC only for trait definitions. Overall, the 27,000 LOC-sized old `rustc_codegen_llvm` code has been split into the new 18,500 LOC-sized new `rustc_codegen_llvm` and the 12,000 LOC-sized `rustc_codegen_ssa`. We can say that this refactoring allowed the reuse of approximately 10,000 LOC that would otherwise have had to be duplicated between the multiple backends of `rustc`. The refactored version of `rustc`'s backend introduced no regression over the test suite nor in performance benchmark, which is in coherence with the nature of the refactoring that used only compile-time parametricity (no trait objects). |