zig

commit 530cc2c1111699d9d02ad9ebef94efa6b99f5205 (tree)
parent 46b60dc06945152eee8280b8ff5b1e629ed74553
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Thu, 28 Aug 2025 18:29:48 -0700

std.Io.Reader: work around llvm backend bug

tracked by #25067 and I already have a fix cooking in another branch

Diffstat:
M
lib/std/Io/Reader.zig
 | 
12
++++++++++--

1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/lib/std/Io/Reader.zig b/lib/std/Io/Reader.zig
@@ -1163,7 +1163,11 @@ pub inline fn takeStruct(r: *Reader, comptime T: type, endian: std.builtin.Endia
         .@"struct" => |info| switch (info.layout) {
             .auto => @compileError("ill-defined memory layout"),
             .@"extern" => {
-                var res = (try r.takeStructPointer(T)).*;
+                // This code works around https://github.com/ziglang/zig/issues/25067
+                // by avoiding a call to `peekStructPointer`.
+                const struct_bytes = try r.takeArray(@sizeOf(T));
+                var res: T = undefined;
+                @memcpy(@as([]u8, @ptrCast(&res)), struct_bytes);
                 if (native_endian != endian) std.mem.byteSwapAllFields(T, &res);
                 return res;
             },
@@ -1188,7 +1192,11 @@ pub inline fn peekStruct(r: *Reader, comptime T: type, endian: std.builtin.Endia
         .@"struct" => |info| switch (info.layout) {
             .auto => @compileError("ill-defined memory layout"),
             .@"extern" => {
-                var res = (try r.peekStructPointer(T)).*;
+                // This code works around https://github.com/ziglang/zig/issues/25067
+                // by avoiding a call to `peekStructPointer`.
+                const struct_bytes = try r.peekArray(@sizeOf(T));
+                var res: T = undefined;
+                @memcpy(@as([]u8, @ptrCast(&res)), struct_bytes);
                 if (native_endian != endian) std.mem.byteSwapAllFields(T, &res);
                 return res;
             },