Merge branch 'Xe-expose-callMain'

closes #3891

1 files changed, 48 insertions, 0 deletions

diff --git a/lib/std/start_windows_tls.zig b/lib/std/start_windows_tls.zig
new file mode 100644
index 0000000000..f6dd2bc132
--- /dev/null
+++ b/lib/std/start_windows_tls.zig
@@ -0,0 +1,48 @@
+const std = @import("std");
+const builtin = std.builtin;
+
+export var _tls_index: u32 = std.os.windows.TLS_OUT_OF_INDEXES;
+export var _tls_start: u8 linksection(".tls") = 0;
+export var _tls_end: u8 linksection(".tls$ZZZ") = 0;
+export var __xl_a: std.os.windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLA") = null;
+export var __xl_z: std.os.windows.PIMAGE_TLS_CALLBACK linksection(".CRT$XLZ") = null;
+
+comptime {
+    if (builtin.arch == .i386) {
+        // The __tls_array is the offset of the ThreadLocalStoragePointer field
+        // in the TEB block whose base address held in the %fs segment.
+        asm (
+            \\ .global __tls_array
+            \\ __tls_array = 0x2C
+        );
+    }
+}
+
+// TODO this is how I would like it to be expressed
+// TODO also note, ReactOS has a +1 on StartAddressOfRawData and AddressOfCallBacks. Investigate
+// why they do that.
+//export const _tls_used linksection(".rdata$T") = std.os.windows.IMAGE_TLS_DIRECTORY {
+//    .StartAddressOfRawData = @ptrToInt(&_tls_start),
+//    .EndAddressOfRawData = @ptrToInt(&_tls_end),
+//    .AddressOfIndex = @ptrToInt(&_tls_index),
+//    .AddressOfCallBacks = @ptrToInt(__xl_a),
+//    .SizeOfZeroFill = 0,
+//    .Characteristics = 0,
+//};
+// This is the workaround because we can't do @ptrToInt at comptime like that.
+pub const IMAGE_TLS_DIRECTORY = extern struct {
+    StartAddressOfRawData: *c_void,
+    EndAddressOfRawData: *c_void,
+    AddressOfIndex: *c_void,
+    AddressOfCallBacks: *c_void,
+    SizeOfZeroFill: u32,
+    Characteristics: u32,
+};
+export const _tls_used linksection(".rdata$T") = IMAGE_TLS_DIRECTORY{
+    .StartAddressOfRawData = &_tls_start,
+    .EndAddressOfRawData = &_tls_end,
+    .AddressOfIndex = &_tls_index,
+    .AddressOfCallBacks = &__xl_a,
+    .SizeOfZeroFill = 0,
+    .Characteristics = 0,
+};