doc: show feature-specific documents in rustdoc output

Author: equation314

Cargo.toml

@@ -7,7 +7,6 @@ authors = ["Yuekai Jia <[email protected]>"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-cfg-if = "1.0"
 bitflags = "2.1"
 memory_addr = { path = "../memory_addr" }
 

src/arch/mod.rs

@@ -1,9 +1,9 @@
-cfg_if::cfg_if! {
-    if #[cfg(any(target_arch = "x86_64"))] {
-        pub mod x86_64;
-    } else if #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))] {
-        pub mod riscv;
-    } else if #[cfg(target_arch = "aarch64")] {
-        pub mod aarch64;
-    }
-}
+#[cfg(target_arch = "x86_64")]
+pub mod x86_64;
+
+#[doc(cfg(any(target_arch = "riscv32", target_arch = "riscv64")))]
+pub mod riscv;
+
+// TODO: `#[cfg(any(target_arch = "aarch64", doc))]` does not work.
+#[doc(cfg(target_arch = "aarch64"))]
+pub mod aarch64;

src/lib.rs

@@ -1,12 +1,14 @@
 #![no_std]
 #![feature(const_trait_impl)]
+#![feature(doc_auto_cfg)]
+#![feature(doc_cfg)]
 
 mod arch;
 
 use core::fmt::Debug;
 use memory_addr::PhysAddr;
 
-pub use arch::*;
+pub use self::arch::*;
 
 bitflags::bitflags! {
     #[derive(Debug, Clone, Copy)]