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|
const std = @import("std");
const assert = std.debug.assert;
const bits = @import("bits.zig");
const Register = bits.Register;
const RegisterManagerFn = @import("../../register_manager.zig").RegisterManager;
const Type = @import("../../type.zig").Type;
const Module = @import("../../Module.zig");
pub const Class = union(enum) {
memory,
byval,
i32_array: u8,
i64_array: u8,
fn arrSize(total_size: u64, arr_size: u64) Class {
const count = @as(u8, @intCast(std.mem.alignForward(u64, total_size, arr_size) / arr_size));
if (arr_size == 32) {
return .{ .i32_array = count };
} else {
return .{ .i64_array = count };
}
}
};
pub const Context = enum { ret, arg };
pub fn classifyType(ty: Type, mod: *Module, ctx: Context) Class {
assert(ty.hasRuntimeBitsIgnoreComptime(mod));
var maybe_float_bits: ?u16 = null;
const max_byval_size = 512;
const ip = &mod.intern_pool;
switch (ty.zigTypeTag(mod)) {
.Struct => {
const bit_size = ty.bitSize(mod);
if (ty.containerLayout(mod) == .Packed) {
if (bit_size > 64) return .memory;
return .byval;
}
if (bit_size > max_byval_size) return .memory;
const float_count = countFloats(ty, mod, &maybe_float_bits);
if (float_count <= byval_float_count) return .byval;
const fields = ty.structFieldCount(mod);
var i: u32 = 0;
while (i < fields) : (i += 1) {
const field_ty = ty.structFieldType(i, mod);
const field_alignment = ty.structFieldAlign(i, mod);
const field_size = field_ty.bitSize(mod);
if (field_size > 32 or field_alignment.compare(.gt, .@"32")) {
return Class.arrSize(bit_size, 64);
}
}
return Class.arrSize(bit_size, 32);
},
.Union => {
const bit_size = ty.bitSize(mod);
const union_obj = mod.typeToUnion(ty).?;
if (union_obj.getLayout(ip) == .Packed) {
if (bit_size > 64) return .memory;
return .byval;
}
if (bit_size > max_byval_size) return .memory;
const float_count = countFloats(ty, mod, &maybe_float_bits);
if (float_count <= byval_float_count) return .byval;
for (union_obj.field_types.get(ip), 0..) |field_ty, field_index| {
if (field_ty.toType().bitSize(mod) > 32 or
mod.unionFieldNormalAlignment(union_obj, @intCast(field_index)).compare(.gt, .@"32"))
{
return Class.arrSize(bit_size, 64);
}
}
return Class.arrSize(bit_size, 32);
},
.Bool, .Float => return .byval,
.Int => {
// TODO this is incorrect for _BitInt(128) but implementing
// this correctly makes implementing compiler-rt impossible.
// const bit_size = ty.bitSize(mod);
// if (bit_size > 64) return .memory;
return .byval;
},
.Enum, .ErrorSet => {
const bit_size = ty.bitSize(mod);
if (bit_size > 64) return .memory;
return .byval;
},
.Vector => {
const bit_size = ty.bitSize(mod);
// TODO is this controlled by a cpu feature?
if (ctx == .ret and bit_size > 128) return .memory;
if (bit_size > 512) return .memory;
return .byval;
},
.Optional => {
assert(ty.isPtrLikeOptional(mod));
return .byval;
},
.Pointer => {
assert(!ty.isSlice(mod));
return .byval;
},
.ErrorUnion,
.Frame,
.AnyFrame,
.NoReturn,
.Void,
.Type,
.ComptimeFloat,
.ComptimeInt,
.Undefined,
.Null,
.Fn,
.Opaque,
.EnumLiteral,
.Array,
=> unreachable,
}
}
const byval_float_count = 4;
fn countFloats(ty: Type, mod: *Module, maybe_float_bits: *?u16) u32 {
const ip = &mod.intern_pool;
const target = mod.getTarget();
const invalid = std.math.maxInt(u32);
switch (ty.zigTypeTag(mod)) {
.Union => {
const union_obj = mod.typeToUnion(ty).?;
var max_count: u32 = 0;
for (union_obj.field_types.get(ip)) |field_ty| {
const field_count = countFloats(field_ty.toType(), mod, maybe_float_bits);
if (field_count == invalid) return invalid;
if (field_count > max_count) max_count = field_count;
if (max_count > byval_float_count) return invalid;
}
return max_count;
},
.Struct => {
const fields_len = ty.structFieldCount(mod);
var count: u32 = 0;
var i: u32 = 0;
while (i < fields_len) : (i += 1) {
const field_ty = ty.structFieldType(i, mod);
const field_count = countFloats(field_ty, mod, maybe_float_bits);
if (field_count == invalid) return invalid;
count += field_count;
if (count > byval_float_count) return invalid;
}
return count;
},
.Float => {
const float_bits = maybe_float_bits.* orelse {
const float_bits = ty.floatBits(target);
if (float_bits != 32 and float_bits != 64) return invalid;
maybe_float_bits.* = float_bits;
return 1;
};
if (ty.floatBits(target) == float_bits) return 1;
return invalid;
},
.Void => return 0,
else => return invalid,
}
}
pub const callee_preserved_regs = [_]Register{ .r4, .r5, .r6, .r7, .r8, .r10 };
pub const caller_preserved_regs = [_]Register{ .r0, .r1, .r2, .r3 };
pub const c_abi_int_param_regs = [_]Register{ .r0, .r1, .r2, .r3 };
pub const c_abi_int_return_regs = [_]Register{ .r0, .r1 };
const allocatable_registers = callee_preserved_regs ++ caller_preserved_regs;
pub const RegisterManager = RegisterManagerFn(@import("CodeGen.zig"), Register, &allocatable_registers);
// Register classes
const RegisterBitSet = RegisterManager.RegisterBitSet;
pub const RegisterClass = struct {
pub const gp: RegisterBitSet = blk: {
var set = RegisterBitSet.initEmpty();
set.setRangeValue(.{
.start = 0,
.end = caller_preserved_regs.len + callee_preserved_regs.len,
}, true);
break :blk set;
};
};
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