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-rw-r--r--lib/std/Thread.zig300
1 files changed, 173 insertions, 127 deletions
diff --git a/lib/std/Thread.zig b/lib/std/Thread.zig
index cbdcf00e9f..73678714d0 100644
--- a/lib/std/Thread.zig
+++ b/lib/std/Thread.zig
@@ -24,17 +24,6 @@ pub const Condition = @import("Thread/Condition.zig");
pub const spinLoopHint = @compileError("deprecated: use std.atomic.spinLoopHint");
-test "std.Thread" {
- // Doesn't use testing.refAllDecls() since that would pull in the compileError spinLoopHint.
- _ = AutoResetEvent;
- _ = Futex;
- _ = ResetEvent;
- _ = StaticResetEvent;
- _ = Mutex;
- _ = Semaphore;
- _ = Condition;
-}
-
pub const use_pthreads = target.os.tag != .windows and std.builtin.link_libc;
const Thread = @This();
@@ -50,7 +39,6 @@ else
impl: Impl,
/// Represents a unique ID per thread.
-/// May be an integer or pointer depending on the platform.
pub const Id = u64;
/// Returns the platform ID of the callers thread.
@@ -79,7 +67,7 @@ pub const SpawnConfig = struct {
stack_size: usize = 16 * 1024 * 1024,
};
-pub const SpawnError = error {
+pub const SpawnError = error{
/// A system-imposed limit on the number of threads was encountered.
/// There are a number of limits that may trigger this error:
/// * the RLIMIT_NPROC soft resource limit (set via setrlimit(2)),
@@ -115,7 +103,7 @@ pub const SpawnError = error {
/// or call `detach()` to excuse the caller from calling `join()` and have the thread clean up its resources on completion`.
pub fn spawn(config: SpawnConfig, comptime function: anytype, args: anytype) SpawnError!Thread {
if (std.builtin.single_threaded) {
- @compileError("cannot spawn thread when building in single-threaded mode");
+ @compileError("Cannot spawn thread when building in single-threaded mode");
}
const impl = try Impl.spawn(config, function, args);
@@ -132,11 +120,13 @@ pub fn getHandle(self: Thread) Handle {
}
/// Release the obligation of the caller to call `join()` and have the thread clean up its own resources on completion.
+/// Once called, this consumes the Thread object and invoking any other functions on it is considered undefined behavior.
pub fn detach(self: Thread) void {
return self.impl.detach();
}
/// Waits for the thread to complete, then deallocates any resources created on `spawn()`.
+/// Once called, this consumes the Thread object and invoking any other functions on it is considered undefined behavior.
pub fn join(self: Thread) void {
return self.impl.join();
}
@@ -200,6 +190,8 @@ fn callFn(comptime f: anytype, args: anytype) switch (Impl) {
}
}
+/// We can't compile error in the `Impl` switch statement as its eagerly evaluated.
+/// So instead, we compile-error on the methods themselves for platforms which don't support threads.
const UnsupportedImpl = struct {
pub const ThreadHandle = void;
@@ -212,7 +204,7 @@ const UnsupportedImpl = struct {
}
fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
- return unsupported(.{config, f, args});
+ return unsupported(.{ config, f, args });
}
fn getHandle(self: Impl) ThreadHandle {
@@ -225,7 +217,7 @@ const UnsupportedImpl = struct {
fn join(self: Impl) void {
return unsupported(self);
- }
+ }
fn unsupported(unusued: anytype) noreturn {
@compileLog("Unsupported operating system", target.os.tag);
@@ -244,6 +236,7 @@ const WindowsThreadImpl = struct {
}
fn getCpuCount() !usize {
+ // Faster than calling into GetSystemInfo(), even if amortized.
return windows.peb().NumberOfProcessors;
}
@@ -299,16 +292,17 @@ const WindowsThreadImpl = struct {
// Its also fine if the limit here is incorrect as stack size is only a hint.
var stack_size = std.math.cast(u32, config.stack_size) catch std.math.maxInt(u32);
stack_size = std.math.max(64 * 1024, stack_size);
-
+
instance.thread.thread_handle = windows.kernel32.CreateThread(
- null,
- stack_size,
- Instance.entryFn,
- @ptrCast(*c_void, instance),
- 0,
+ null,
+ stack_size,
+ Instance.entryFn,
+ @ptrCast(*c_void, instance),
+ 0,
null,
) orelse {
- return windows.unexpectedError(windows.kernel32.GetLastError());
+ const errno = windows.kernel32.GetLastError();
+ return windows.unexpectedError(errno);
};
return Impl{ .thread = &instance.thread };
@@ -332,7 +326,7 @@ const WindowsThreadImpl = struct {
windows.CloseHandle(self.thread.thread_handle);
assert(self.thread.completion.load(.SeqCst) == .completed);
self.thread.free();
- }
+ }
};
const PosixThreadImpl = struct {
@@ -374,7 +368,9 @@ const PosixThreadImpl = struct {
fn getCpuCount() !usize {
switch (target.os.tag) {
- .linux => return LinuxThreadImpl.getCpuCount(),
+ .linux => {
+ return LinuxThreadImpl.getCpuCount();
+ },
.openbsd => {
var count: c_int = undefined;
var count_size: usize = @sizeOf(c_int);
@@ -413,6 +409,7 @@ const PosixThreadImpl = struct {
const Instance = struct {
fn entryFn(raw_arg: ?*c_void) callconv(.C) ?*c_void {
+ // @alignCast() below doesn't support zero-sized-types (ZST)
if (@sizeOf(Args) < 1) {
return callFn(f, @as(Args, undefined));
}
@@ -457,8 +454,9 @@ const PosixThreadImpl = struct {
fn detach(self: Impl) void {
switch (c.pthread_detach(self.handle)) {
- os.EINVAL => unreachable,
- os.ESRCH => unreachable,
+ 0 => {},
+ os.EINVAL => unreachable, // thread handle is not joinable
+ os.ESRCH => unreachable, // thread handle is invalid
else => unreachable,
}
}
@@ -466,9 +464,9 @@ const PosixThreadImpl = struct {
fn join(self: Impl) void {
switch (c.pthread_join(self.handle, null)) {
0 => {},
- os.EINVAL => unreachable,
- os.ESRCH => unreachable,
- os.EDEADLK => unreachable,
+ os.EINVAL => unreachable, // thread handle is not joinable (or another thread is already joining in)
+ os.ESRCH => unreachable, // thread handle is invalid
+ os.EDEADLK => unreachable, // two threads tried to join each other
else => unreachable,
}
}
@@ -476,7 +474,7 @@ const PosixThreadImpl = struct {
const LinuxThreadImpl = struct {
const linux = os.linux;
-
+
pub const ThreadHandle = i32;
threadlocal var tls_thread_id: ?Id = null;
@@ -491,7 +489,8 @@ const LinuxThreadImpl = struct {
fn getCpuCount() !usize {
const cpu_set = try os.sched_getaffinity(0);
- return @as(usize, os.CPU_COUNT(cpu_set)); // TODO should not need this usize cast
+ // TODO: should not need this usize cast
+ return @as(usize, os.CPU_COUNT(cpu_set));
}
thread: *ThreadCompletion,
@@ -547,7 +546,7 @@ const LinuxThreadImpl = struct {
bytes = std.mem.alignForward(bytes, std.mem.page_size);
break :blk bytes;
};
-
+
// map all memory needed without read/write permissions
// to avoid committing the whole region right away
const mapped = os.mmap(
@@ -654,7 +653,7 @@ const LinuxThreadImpl = struct {
switch (linux.getErrno(linux.futex_wait(
&self.thread.child_tid.value,
- linux.FUTEX_WAIT,
+ linux.FUTEX_WAIT,
tid,
null,
))) {
@@ -671,98 +670,145 @@ const LinuxThreadImpl = struct {
extern fn __unmap_and_exit(ptr: usize, len: usize) callconv(.C) noreturn;
comptime {
if (target.os.tag == .linux) {
- asm(switch (target.cpu.arch) {
- .i386 => (
- \\.text
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, @function
- \\__unmap_and_exit:
- \\ movl $91, %eax
- \\ movl 4(%esp), %ebx
- \\ movl 8(%esp), %ecx
- \\ int $128
- \\ xorl %ebx, %ebx
- \\ movl $1, %eax
- \\ int $128
- ),
- .x86_64 => (
- \\.text
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, @function
- \\__unmap_and_exit:
- \\ movl $11, %eax
- \\ syscall
- \\ xor %rdi, %rdi
- \\ movl $60, %eax
- \\ syscall
- ),
- .arm, .armeb, .thumb, .thumbeb => (
- \\.syntax unified
- \\.text
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, %function
- \\__unmap_and_exit:
- \\ mov r7, #91
- \\ svc 0
- \\ mov r7, #1
- \\ svc 0
- ),
- .aarch64, .aarch64_be, .aarch64_32 => (
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, %function
- \\__unmap_and_exit:
- \\ mov x8, #215
- \\ svc 0
- \\ mov x8, #93
- \\ svc 0
- ),
- .mips, .mipsel, => (
- \\.set noreorder
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit,@function
- \\__unmap_and_exit:
- \\ move $sp, $25
- \\ li $2, 4091
- \\ syscall
- \\ li $4, 0
- \\ li $2, 4001
- \\ syscall
- ),
- .mips64, .mips64el => (
- \\.set noreorder
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, @function
- \\__unmap_and_exit:
- \\ li $2, 4091
- \\ syscall
- \\ li $4, 0
- \\ li $2, 4001
- \\ syscall
- ),
- .powerpc, .powerpc64, .powerpc64le => (
- \\.text
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, %function
- \\__unmap_and_exit:
- \\ li 0, 91
- \\ sc
- \\ li 0, 1
- \\ sc
- \\ blr
- ),
- .riscv64 => (
- \\.global __unmap_and_exit
- \\.type __unmap_and_exit, %function
- \\__unmap_and_exit:
- \\ li a7, 215
- \\ ecall
- \\ li a7, 93
- \\ ecall
- ),
- else => |cpu_arch| {
- @compileLog("linux arch", cpu_arch, "is not supported");
- },
- });
+ asm (switch (target.cpu.arch) {
+ .i386 => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ movl $91, %eax
+ \\ movl 4(%esp), %ebx
+ \\ movl 8(%esp), %ecx
+ \\ int $128
+ \\ xorl %ebx, %ebx
+ \\ movl $1, %eax
+ \\ int $128
+ ),
+ .x86_64 => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ movl $11, %eax
+ \\ syscall
+ \\ xor %rdi, %rdi
+ \\ movl $60, %eax
+ \\ syscall
+ ),
+ .arm, .armeb, .thumb, .thumbeb => (
+ \\.syntax unified
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, %function
+ \\__unmap_and_exit:
+ \\ mov r7, #91
+ \\ svc 0
+ \\ mov r7, #1
+ \\ svc 0
+ ),
+ .aarch64, .aarch64_be, .aarch64_32 => (
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, %function
+ \\__unmap_and_exit:
+ \\ mov x8, #215
+ \\ svc 0
+ \\ mov x8, #93
+ \\ svc 0
+ ),
+ .mips,
+ .mipsel,
+ => (
+ \\.set noreorder
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit,@function
+ \\__unmap_and_exit:
+ \\ move $sp, $25
+ \\ li $2, 4091
+ \\ syscall
+ \\ li $4, 0
+ \\ li $2, 4001
+ \\ syscall
+ ),
+ .mips64, .mips64el => (
+ \\.set noreorder
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, @function
+ \\__unmap_and_exit:
+ \\ li $2, 4091
+ \\ syscall
+ \\ li $4, 0
+ \\ li $2, 4001
+ \\ syscall
+ ),
+ .powerpc, .powerpc64, .powerpc64le => (
+ \\.text
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, %function
+ \\__unmap_and_exit:
+ \\ li 0, 91
+ \\ sc
+ \\ li 0, 1
+ \\ sc
+ \\ blr
+ ),
+ .riscv64 => (
+ \\.global __unmap_and_exit
+ \\.type __unmap_and_exit, %function
+ \\__unmap_and_exit:
+ \\ li a7, 215
+ \\ ecall
+ \\ li a7, 93
+ \\ ecall
+ ),
+ else => |cpu_arch| {
+ @compileLog("linux arch", cpu_arch, "is not supported");
+ },
+ });
}
}
-}; \ No newline at end of file
+};
+
+test "std.Thread" {
+ // Doesn't use testing.refAllDecls() since that would pull in the compileError spinLoopHint.
+ _ = AutoResetEvent;
+ _ = Futex;
+ _ = ResetEvent;
+ _ = StaticResetEvent;
+ _ = Mutex;
+ _ = Semaphore;
+ _ = Condition;
+}
+
+fn testIncrementNotify(value: *usize, event: *ResetEvent) void {
+ value.* += 1;
+ event.set();
+}
+
+test "Thread.join" {
+ if (std.builtin.single_threaded) return error.SkipZigTest;
+
+ var value: usize = 0;
+ var event: ResetEvent = undefined;
+ try event.init();
+ defer event.deinit();
+
+ const thread = try Thread.spawn(.{}, testIncrementNotify, .{&value, &event});
+ thread.join();
+
+ try std.testing.expectEqual(value, 1);
+}
+
+test "Thread.detach" {
+ if (std.builtin.single_threaded) return error.SkipZigTest;
+
+ var value: usize = 0;
+ var event: ResetEvent = undefined;
+ try event.init();
+ defer event.deinit();
+
+ const thread = try Thread.spawn(.{}, testIncrementNotify, .{&value, &event});
+ thread.detach();
+
+ event.wait();
+ try std.testing.expectEqual(value, 1);
+} \ No newline at end of file
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