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x86_64: fix ub that the llvm backend was hiding

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This commit is contained in:
Jacob Young 2023-11-04 04:58:42 -04:00
parent 7b1a644d6e
commit 6553359f39
1 changed files with 3 additions and 9 deletions
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12
src/arch/x86_64/Encoding.zig
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@ -62,8 +62,7 @@ pub fn findByMnemonic(
.rex, .rex_short => if (!rex_required) continue,
else => {},
}
for (input_ops, data.ops) |input_op, data_op|
if (!input_op.isSubset(data_op)) continue :next;
for (input_ops, data.ops) |input_op, data_op| if (!input_op.isSubset(data_op)) continue :next;
const enc = Encoding{ .mnemonic = mnemonic, .data = data };
if (shortest_enc) |previous_shortest_enc| {
@ -828,18 +827,13 @@ const mnemonic_to_encodings_map = init: {
for (&data_storage, entries, 0..) |*data, entry, data_index| {
data.* = .{
.op_en = entry[1],
.ops = undefined,
.ops = (entry[2] ++ .{.none} ** (data.ops.len - entry[2].len)).*,
.opc_len = entry[3].len,
.opc = undefined,
.opc = (entry[3] ++ .{undefined} ** (data.opc.len - entry[3].len)).*,
.modrm_ext = entry[4],
.mode = entry[5],
.feature = entry[6],
};
// TODO: use `@memcpy` for these. When I did that, I got a false positive
// compile error for this copy happening at compile time.
std.mem.copyForwards(Op, &data.ops, entry[2]);
std.mem.copyForwards(u8, &data.opc, entry[3]);
while (mnemonic_int < @intFromEnum(entry[0])) : (mnemonic_int += 1) {
mnemonic_map[mnemonic_int] = data_storage[mnemonic_start..data_index];
mnemonic_start = data_index;