zig/lib/std/os/windows/tls.zig
Alex Rønne Petersen 537a873b17
Initial port work for *-windows-itanium support.
https://llvm.org/docs/HowToBuildWindowsItaniumPrograms.html

This is a weird middle ground between `*-windows-gnu` and `*-windows-msvc`. It
uses the C++ ABI of the former while using the system libraries of the latter.
2024-09-28 21:43:52 +02:00

51 lines
2.1 KiB
Zig

const std = @import("std");
const builtin = @import("builtin");
const windows = std.os.windows;
export var _tls_index: u32 = std.os.windows.TLS_OUT_OF_INDEXES;
export var _tls_start: ?*anyopaque linksection(".tls") = null;
export var _tls_end: ?*anyopaque linksection(".tls$ZZZ") = null;
export var __xl_a: windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLA") = null;
export var __xl_z: windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLZ") = null;
comptime {
if (builtin.cpu.arch == .x86 and !builtin.abi.isGnu() and builtin.zig_backend != .stage2_c) {
// The __tls_array is the offset of the ThreadLocalStoragePointer field
// in the TEB block whose base address held in the %fs segment.
asm (
\\ .global __tls_array
\\ __tls_array = 0x2C
);
}
}
// TODO this is how I would like it to be expressed
//export const _tls_used linksection(".rdata$T") = std.os.windows.IMAGE_TLS_DIRECTORY {
// .StartAddressOfRawData = @intFromPtr(&_tls_start),
// .EndAddressOfRawData = @intFromPtr(&_tls_end),
// .AddressOfIndex = @intFromPtr(&_tls_index),
// .AddressOfCallBacks = @intFromPtr(__xl_a),
// .SizeOfZeroFill = 0,
// .Characteristics = 0,
//};
// This is the workaround because we can't do @intFromPtr at comptime like that.
pub const IMAGE_TLS_DIRECTORY = extern struct {
StartAddressOfRawData: *?*anyopaque,
EndAddressOfRawData: *?*anyopaque,
AddressOfIndex: *u32,
AddressOfCallBacks: [*:null]windows.PIMAGE_TLS_CALLBACK,
SizeOfZeroFill: u32,
Characteristics: u32,
};
export const _tls_used linksection(".rdata$T") = IMAGE_TLS_DIRECTORY{
.StartAddressOfRawData = &_tls_start,
.EndAddressOfRawData = &_tls_end,
.AddressOfIndex = &_tls_index,
// __xl_a is just a global variable containing a null pointer; the actual callbacks sit in
// between __xl_a and __xl_z. So we need to skip over __xl_a here. If there are no callbacks,
// this just means we point to __xl_z (the null terminator).
.AddressOfCallBacks = @as([*:null]windows.PIMAGE_TLS_CALLBACK, @ptrCast(&__xl_a)) + 1,
.SizeOfZeroFill = 0,
.Characteristics = 0,
};