Commit f9fe548e41

Cody Tapscott <topolarity@tapscott.me>
2022-10-28 17:24:12
std.crypto: Add `isComptime` guard around intrinsics
Comptime code can't execute assembly code, so we need some way to force comptime code to use the generic path. This should be replaced with whatever is implemented for #868, when that day comes. I am seeing that the result for the hash is incorrect in stage1 and crashes stage2, so presumably this never worked correctly. I will follow up on that soon.
master
1 parent 4c1f71e
Changed files (1)
lib
std
crypto
sha2.zig
lib/std/crypto/sha2.zig
@@ -71,6 +71,12 @@ const Sha256Params = Sha2Params32{
 
 const v4u32 = @Vector(4, u32);
 
+// TODO: Remove once https://github.com/ziglang/zig/issues/868 is resolved.
+fn isComptime() bool {
+    var a: u8 = 0;
+    return @typeInfo(@TypeOf(.{a})).Struct.fields[0].is_comptime;
+}
+
 /// SHA-224
 pub const Sha224 = Sha2x32(Sha224Params);
 
@@ -187,7 +193,7 @@ fn Sha2x32(comptime params: Sha2Params32) type {
             }
 
             switch (builtin.cpu.arch) {
-                .aarch64 => if (comptime builtin.cpu.features.isEnabled(@enumToInt(std.Target.aarch64.Feature.sha2))) {
+                .aarch64 => if (!isComptime() and comptime builtin.cpu.features.isEnabled(@enumToInt(std.Target.aarch64.Feature.sha2))) {
                     var x: v4u32 = d.s[0..4].*;
                     var y: v4u32 = d.s[4..8].*;
                     const s_v = @ptrCast(*[16]v4u32, &s);
@@ -224,7 +230,7 @@ fn Sha2x32(comptime params: Sha2Params32) type {
                     d.s[4..8].* = y +% @as(v4u32, d.s[4..8].*);
                     return;
                 },
-                .x86_64 => if (comptime builtin.cpu.features.isEnabled(@enumToInt(std.Target.x86.Feature.sha))) {
+                .x86_64 => if (!isComptime() and comptime builtin.cpu.features.isEnabled(@enumToInt(std.Target.x86.Feature.sha))) {
                     var x: v4u32 = [_]u32{ d.s[5], d.s[4], d.s[1], d.s[0] };
                     var y: v4u32 = [_]u32{ d.s[7], d.s[6], d.s[3], d.s[2] };
                     const s_v = @ptrCast(*[16]v4u32, &s);