mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-02-03 05:03:38 +00:00
Code Issues Packages Projects Releases Wiki Activity

x64: account for non-pow-two stores via register deref

Browse Source 
In this case, we need to proceed rather carefully to avoid writing
containing register width rather than the precise amount of bytes.
This commit is contained in:
Jakub Konka 2022-06-07 18:04:58 +02:00
parent 117f9f69e7
commit fc015231ad
1 changed files with 40 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
src/arch/x86_64/CodeGen.zig
View File

@ -2732,15 +2732,46 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
}
},
.register => |src_reg| {
_ = try self.addInst(.{
.tag = .mov,
.ops = Mir.Inst.Ops.encode(.{
.reg1 = reg.to64(),
.reg2 = registerAlias(src_reg, @intCast(u32, abi_size)),
.flags = 0b10,
}),
.data = .{ .imm = 0 },
});
const src_reg_lock = self.register_manager.lockReg(src_reg);
defer if (src_reg_lock) |lock| self.register_manager.unlockReg(lock);
// TODO common code-path with genSetStack, refactor!
if (!math.isPowerOfTwo(abi_size)) {
const tmp_reg = try self.copyToTmpRegister(value_ty, value);
var next_offset: i32 = 0;
var remainder = abi_size;
while (remainder > 0) {
const nearest_power_of_two = @as(u6, 1) << math.log2_int(u3, @intCast(u3, remainder));
_ = try self.addInst(.{
.tag = .mov,
.ops = Mir.Inst.Ops.encode(.{
.reg1 = reg.to64(),
.reg2 = registerAlias(tmp_reg, nearest_power_of_two),
.flags = 0b10,
}),
.data = .{ .imm = @bitCast(u32, -next_offset) },
});
if (nearest_power_of_two > 1) {
try self.genShiftBinOpMir(.shr, value_ty, tmp_reg, .{ .immediate = nearest_power_of_two * 8 });
}
remainder -= nearest_power_of_two;
next_offset -= nearest_power_of_two;
}
} else {
_ = try self.addInst(.{
.tag = .mov,
.ops = Mir.Inst.Ops.encode(.{
.reg1 = reg.to64(),
.reg2 = registerAlias(src_reg, @intCast(u32, abi_size)),
.flags = 0b10,
}),
.data = .{ .imm = 0 },
});
}
},
.got_load,
.direct_load,