hexagon: Clobber p0 and remove #[inline(never)]

taiki-e · Dec 6, 2024 · cd12f7b · cd12f7b
1 parent 3d249c7
commit cd12f7b
Show file tree

Hide file tree

Showing 3 changed files with 30 additions and 15 deletions.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -154,7 +154,7 @@ jobs:
             target: i686-unknown-linux-gnu
           - rust: nightly
             target: i686-unknown-linux-gnu
-          - rust: nightly-2023-08-24 # Rust 1.74, LLVM 17 (oldest version that MaybeUninit register is supported)
+          - rust: nightly-2024-11-29 # Rust 1.85, LLVM 19 (oldest version we can use asm_experimental_arch on this target)
             target: hexagon-unknown-linux-musl
           - rust: nightly
             target: hexagon-unknown-linux-musl

diff --git a/build.rs b/build.rs
@@ -106,12 +106,21 @@ fn main() {
                 }
             }
         }
-        "avr" | "hexagon" | "m68k" | "mips" | "mips32r6" | "mips64" | "mips64r6" | "msp430"
-        | "powerpc" | "powerpc64" | "xtensa" => {
+        "avr" | "m68k" | "mips" | "mips32r6" | "mips64" | "mips64r6" | "msp430" | "powerpc"
+        | "powerpc64" | "xtensa" => {
             if version.nightly && is_allowed_feature("asm_experimental_arch") {
                 println!("cargo:rustc-cfg=atomic_maybe_uninit_unstable_asm_experimental_arch");
             }
         }
+        "hexagon" => {
+            // https://github.com/rust-lang/rust/pull/133452 merged in Rust 1.85 (nightly-2024-11-29).
+            if version.nightly
+                && version.probe(85, 2024, 11, 28)
+                && is_allowed_feature("asm_experimental_arch")
+            {
+                println!("cargo:rustc-cfg=atomic_maybe_uninit_unstable_asm_experimental_arch");
+            }
+        }
         "sparc" | "sparc64" => {
             // https://github.com/rust-lang/rust/pull/132472 merged in Rust 1.84 (nightly-2024-11-08).
             if version.nightly

diff --git a/src/arch/hexagon.rs b/src/arch/hexagon.rs
@@ -75,7 +75,7 @@ macro_rules! atomic {
     ($ty:ident) => {
         atomic_load_store!($ty, "w", "");
         impl AtomicSwap for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_swap(
                 dst: *mut MaybeUninit<Self>,
                 val: MaybeUninit<Self>,
@@ -94,14 +94,15 @@ macro_rules! atomic {
                         dst = in(reg) dst,
                         val = in(reg) val,
                         out = out(reg) out,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                 }
                 out
             }
         }
         impl AtomicCompareExchange for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_compare_exchange(
                 dst: *mut MaybeUninit<Self>,
                 old: MaybeUninit<Self>,
@@ -131,7 +132,8 @@ macro_rules! atomic {
                         new = in(reg) new,
                         out = out(reg) out,
                         r = inout(reg) r,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                     crate::utils::assert_unchecked(r == 0 || r == 1); // may help remove extra test
                     (out, r != 0)
@@ -145,7 +147,7 @@ macro_rules! atomic_sub_word {
     ($ty:ident, $size:tt) => {
         atomic_load_store!($ty, $size, "u");
         impl AtomicSwap for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_swap(
                 dst: *mut MaybeUninit<Self>,
                 val: MaybeUninit<Self>,
@@ -174,14 +176,15 @@ macro_rules! atomic_sub_word {
                         shift = in(reg) shift,
                         mask = in(reg) mask,
                         tmp = out(reg) _,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                 }
                 out
             }
         }
         impl AtomicCompareExchange for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_compare_exchange(
                 dst: *mut MaybeUninit<Self>,
                 old: MaybeUninit<Self>,
@@ -223,7 +226,8 @@ macro_rules! atomic_sub_word {
                         mask = in(reg) mask,
                         tmp = out(reg) _,
                         r = inout(reg) r,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                     crate::utils::assert_unchecked(r == 0 || r == 1); // may help remove extra test
                     (out, r != 0)
@@ -289,7 +293,7 @@ macro_rules! atomic64 {
             }
         }
         impl AtomicSwap for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_swap(
                 dst: *mut MaybeUninit<Self>,
                 val: MaybeUninit<Self>,
@@ -311,14 +315,15 @@ macro_rules! atomic64 {
                         in("r3") val.pair.hi,
                         out("r4") prev_lo,
                         out("r5") prev_hi,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                     MaybeUninit64 { pair: Pair { lo: prev_lo, hi: prev_hi } }.$ty
                 }
             }
         }
         impl AtomicCompareExchange for $ty {
-            #[inline(never)] // TODO: there is no way to mark p0 as clobbered
+            #[inline]
             unsafe fn atomic_compare_exchange(
                 dst: *mut MaybeUninit<Self>,
                 old: MaybeUninit<Self>,
@@ -356,7 +361,8 @@ macro_rules! atomic64 {
                         in("r5") new.pair.hi,
                         out("r6") prev_lo,
                         out("r7") prev_hi,
-                        options(nostack),
+                        out("p0") _,
+                        options(nostack, preserves_flags),
                     );
                     crate::utils::assert_unchecked(r == 0 || r == 1); // may help remove extra test
                     (MaybeUninit64 { pair: Pair { lo: prev_lo, hi: prev_hi } }.$ty, r != 0)