From 5b32ab671a03e0804e864907d7be4c775b4c6403 Mon Sep 17 00:00:00 2001 From: Camelid Date: Tue, 22 Dec 2020 19:37:23 -0800 Subject: [PATCH] Update and improve `rustc_codegen_{llvm,ssa}` docs These docs were very out of date and misleading. They even said that they codegen'd the *AST*! For some reason, the `rustc_codegen_ssa::base` docs were exactly identical to the `rustc_codegen_llvm::base` docs. They didn't really make sense, because they had LLVM-specific information even though `rustc_codegen_ssa` is supposed to be somewhat generic. So I removed them as they were misleading. --- compiler/rustc_codegen_llvm/src/base.rs | 18 ++++++++---------- compiler/rustc_codegen_llvm/src/common.rs | 1 + compiler/rustc_codegen_ssa/src/base.rs | 15 --------------- 3 files changed, 9 insertions(+), 25 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs index 7d01f6a54995a..d5be3132dee10 100644 --- a/compiler/rustc_codegen_llvm/src/base.rs +++ b/compiler/rustc_codegen_llvm/src/base.rs @@ -1,17 +1,15 @@ -//! Codegen the completed AST to the LLVM IR. -//! -//! Some functions here, such as codegen_block and codegen_expr, return a value -- -//! the result of the codegen to LLVM -- while others, such as codegen_fn -//! and mono_item, are called only for the side effect of adding a -//! particular definition to the LLVM IR output we're producing. +//! Codegen the MIR to the LLVM IR. //! //! Hopefully useful general knowledge about codegen: //! -//! * There's no way to find out the `Ty` type of a Value. Doing so +//! * There's no way to find out the [`Ty`] type of a [`Value`]. Doing so //! would be "trying to get the eggs out of an omelette" (credit: -//! pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`, -//! but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int, -//! int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`. +//! pcwalton). You can, instead, find out its [`llvm::Type`] by calling [`val_ty`], +//! but one [`llvm::Type`] corresponds to many [`Ty`]s; for instance, `tup(int, int, +//! int)` and `rec(x=int, y=int, z=int)` will have the same [`llvm::Type`]. +//! +//! [`Ty`]: rustc_middle::ty::Ty +//! [`val_ty`]: common::val_ty use super::ModuleLlvm; diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs index 34e1b7a60451e..58af9d4cd04a9 100644 --- a/compiler/rustc_codegen_llvm/src/common.rs +++ b/compiler/rustc_codegen_llvm/src/common.rs @@ -314,6 +314,7 @@ impl ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> { } } +/// Get the [LLVM type][Type] of a [`Value`]. pub fn val_ty(v: &Value) -> &Type { unsafe { llvm::LLVMTypeOf(v) } } diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs index 21138f967a273..a10e35e02f3c8 100644 --- a/compiler/rustc_codegen_ssa/src/base.rs +++ b/compiler/rustc_codegen_ssa/src/base.rs @@ -1,18 +1,3 @@ -//! Codegen the completed AST to the LLVM IR. -//! -//! Some functions here, such as `codegen_block` and `codegen_expr`, return a value -- -//! the result of the codegen to LLVM -- while others, such as `codegen_fn` -//! and `mono_item`, are called only for the side effect of adding a -//! particular definition to the LLVM IR output we're producing. -//! -//! Hopefully useful general knowledge about codegen: -//! -//! * There's no way to find out the `Ty` type of a `Value`. Doing so -//! would be "trying to get the eggs out of an omelette" (credit: -//! pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`, -//! but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int, -//! int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`. - use crate::back::write::{ compute_per_cgu_lto_type, start_async_codegen, submit_codegened_module_to_llvm, submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm, ComputedLtoType, OngoingCodegen,