std.sync.atomic: extended atomic helper functions (#8866)

- deprecates `std.Thread.spinLoopHint` and moves it to `std.atomic.spinLoopHint`
- added an Atomic(T) generic wrapper type which replaces atomic.Bool and atomic.Int
- in Atomic(T), selectively expose member functions depending on T and include bitwise atomic methods when T is an Integer
- added fence() and compilerFence() to std.atomic

1 files changed, 8 insertions, 29 deletions

diff --git a/lib/std/Thread.zig b/lib/std/Thread.zig
index fbb3d927e2..fb74f09677 100644
--- a/lib/std/Thread.zig
+++ b/lib/std/Thread.zig
@@ -67,33 +67,7 @@ else switch (std.Target.current.os.tag) {
     else => struct {},
 };
 
-/// Signals the processor that it is inside a busy-wait spin-loop ("spin lock").
-pub inline fn spinLoopHint() void {
-    switch (std.Target.current.cpu.arch) {
-        .i386, .x86_64 => {
-            asm volatile ("pause" ::: "memory");
-        },
-        .arm, .armeb, .thumb, .thumbeb => {
-            // `yield` was introduced in v6k but are also available on v6m.
-            const can_yield = comptime std.Target.arm.featureSetHasAny(std.Target.current.cpu.features, .{ .has_v6k, .has_v6m });
-            if (can_yield) asm volatile ("yield" ::: "memory")
-            // Fallback.
-            else asm volatile ("" ::: "memory");
-        },
-        .aarch64, .aarch64_be, .aarch64_32 => {
-            asm volatile ("isb" ::: "memory");
-        },
-        .powerpc64, .powerpc64le => {
-            // No-op that serves as `yield` hint.
-            asm volatile ("or 27, 27, 27" ::: "memory");
-        },
-        else => {
-            // Do nothing but prevent the compiler from optimizing away the
-            // spinning loop.
-            asm volatile ("" ::: "memory");
-        },
-    }
-}
+pub const spinLoopHint = @compileError("deprecated: use std.atomic.spinLoopHint");
 
 /// Returns the ID of the calling thread.
 /// Makes a syscall every time the function is called.
@@ -597,8 +571,13 @@ pub fn getCurrentThreadId() u64 {
     }
 }
 
-test {
+test "std.Thread" {
     if (!builtin.single_threaded) {
-        std.testing.refAllDecls(@This());
+        _ = AutoResetEvent;
+        _ = ResetEvent;
+        _ = StaticResetEvent;
+        _ = Mutex;
+        _ = Semaphore;
+        _ = Condition;
     }
 }