Remove the no-asm feature

Assembly-related configuration was added in 1621c6d ("Use
`specialized-div-rem` 1.0.0 for division algorithms") to account for
Cranelift not yet supporting assembly. This hasn't been relevant for a
while so remove the unused feature here.

To keep miri tests working, replace one instance of `not(feature =
"no-asm")` with `not(miri)`.

This is the compiler-builtins portion of
rust-lang/rust#144471.

Author: tgross35

builtins-shim/Cargo.toml

@@ -37,10 +37,6 @@ default = ["compiler-builtins"]
 # implementations and also filling in unimplemented intrinsics
 c = ["dep:cc"]
 
-# Workaround for the Cranelift codegen backend. Disables any implementations
-# which use inline assembly and fall back to pure Rust versions (if available).
-no-asm = []
-
 # Workaround for codegen backends which haven't yet implemented `f16` and
 # `f128` support. Disabled any intrinsics which use those types.
 no-f16-f128 = []

builtins-test/Cargo.toml

@@ -33,7 +33,6 @@ utest-macros = { git = "https://github.com/japaric/utest" }
 [features]
 default = ["mangled-names"]
 c = ["compiler_builtins/c"]
-no-asm = ["compiler_builtins/no-asm"]
 no-f16-f128 = ["compiler_builtins/no-f16-f128"]
 mem = ["compiler_builtins/mem"]
 mangled-names = ["compiler_builtins/mangled-names"]

builtins-test/tests/lse.rs

@@ -1,6 +1,6 @@
 #![feature(decl_macro)] // so we can use pub(super)
 #![feature(macro_metavar_expr_concat)]
-#![cfg(all(target_arch = "aarch64", target_os = "linux", not(feature = "no-asm")))]
+#![cfg(all(target_arch = "aarch64", target_os = "linux"))]
 
 /// Translate a byte size to a Rust type.
 macro int_ty {

ci/miri.sh

@@ -14,5 +14,5 @@ targets=(
 )
 for target in "${targets[@]}"; do
     # Only run the `mem` tests to avoid this taking too long.
-    cargo miri test --manifest-path builtins-test/Cargo.toml --features no-asm --target "$target" -- mem
+    cargo miri test --manifest-path builtins-test/Cargo.toml --target "$target" -- mem
 done

ci/run.sh

@@ -34,8 +34,6 @@ else
     "${test_builtins[@]}" --release
     "${test_builtins[@]}" --features c
     "${test_builtins[@]}" --features c --release
-    "${test_builtins[@]}" --features no-asm
-    "${test_builtins[@]}" --features no-asm --release
     "${test_builtins[@]}" --features no-f16-f128
     "${test_builtins[@]}" --features no-f16-f128 --release
     "${test_builtins[@]}" --benches
@@ -58,8 +56,6 @@ symcheck+=(-- build-and-check)
 "${symcheck[@]}" "$target" -- -p compiler_builtins --release
 "${symcheck[@]}" "$target" -- -p compiler_builtins --features c
 "${symcheck[@]}" "$target" -- -p compiler_builtins --features c --release
-"${symcheck[@]}" "$target" -- -p compiler_builtins --features no-asm
-"${symcheck[@]}" "$target" -- -p compiler_builtins --features no-asm --release
 "${symcheck[@]}" "$target" -- -p compiler_builtins --features no-f16-f128
 "${symcheck[@]}" "$target" -- -p compiler_builtins --features no-f16-f128 --release
 

compiler-builtins/Cargo.toml

@@ -35,10 +35,6 @@ default = ["compiler-builtins"]
 # implementations and also filling in unimplemented intrinsics
 c = ["dep:cc"]
 
-# Workaround for the Cranelift codegen backend. Disables any implementations
-# which use inline assembly and fall back to pure Rust versions (if available).
-no-asm = []
-
 # Workaround for codegen backends which haven't yet implemented `f16` and
 # `f128` support. Disabled any intrinsics which use those types.
 no-f16-f128 = []

compiler-builtins/build.rs

@@ -96,10 +96,8 @@ fn configure_libm(target: &Target) {
     // Always use intrinsics
     println!("cargo:rustc-cfg=intrinsics_enabled");
 
-    // The arch module may contain assembly.
-    if !cfg!(feature = "no-asm") {
-        println!("cargo:rustc-cfg=arch_enabled");
-    }
+    // Always use arch-specific code
+    println!("cargo:rustc-cfg=arch_enabled");
 
     println!("cargo:rustc-check-cfg=cfg(optimizations_enabled)");
     if !matches!(target.opt_level.as_str(), "0" | "1") {

compiler-builtins/src/aarch64.rs

@@ -4,7 +4,7 @@ use core::intrinsics;
 
 intrinsics! {
     #[unsafe(naked)]
-    #[cfg(all(target_os = "uefi", not(feature = "no-asm")))]
+    #[cfg(target_os = "uefi")]
     pub unsafe extern "custom" fn __chkstk() {
         core::arch::naked_asm!(
             ".p2align 2",

compiler-builtins/src/arm.rs

@@ -1,5 +1,3 @@
-#![cfg(not(feature = "no-asm"))]
-
 // Interfaces used by naked trampolines.
 // SAFETY: these are defined in compiler-builtins
 unsafe extern "C" {

compiler-builtins/src/hexagon.rs

@@ -1,5 +1,3 @@
-#![cfg(not(feature = "no-asm"))]
-
 use core::arch::global_asm;
 
 global_asm!(include_str!("hexagon/func_macro.s"), options(raw));