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stage2 ARM: implement is_null and is_non_null for ptr-like optionals

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joachimschmidt557 2021-12-21 18:50:01 +01:00
parent 8b6ea9ffe7
commit edcebe7013
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2 changed files with 54 additions and 16 deletions
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50
src/arch/arm/CodeGen.zig
View File

@ -2334,18 +2334,28 @@ fn airCondBr(self: *Self, inst: Air.Inst.Index) !void {
return self.finishAir(inst, .unreach, .{ .none, .none, .none });
}
fn isNull(self: *Self, operand: MCValue) !MCValue {
_ = operand;
// Here you can specialize this instruction if it makes sense to, otherwise the default
// will call isNonNull and invert the result.
return self.fail("TODO call isNonNull and invert the result", .{});
fn isNull(self: *Self, ty: Type, operand: MCValue) !MCValue {
if (ty.isPtrLikeOptional()) {
assert(ty.abiSize(self.target.*) == 4);
const reg_mcv: MCValue = switch (operand) {
.register => operand,
else => .{ .register = try self.copyToTmpRegister(ty, operand) },
};
try self.genArmBinOpCode(undefined, reg_mcv, .{ .immediate = 0 }, false, .cmp_eq, undefined);
return MCValue{ .compare_flags_unsigned = .eq };
} else {
return self.fail("TODO implement non-pointer optionals", .{});
}
}
fn isNonNull(self: *Self, operand: MCValue) !MCValue {
_ = operand;
// Here you can specialize this instruction if it makes sense to, otherwise the default
// will call isNull and invert the result.
return self.fail("TODO call isNull and invert the result", .{});
fn isNonNull(self: *Self, ty: Type, operand: MCValue) !MCValue {
const is_null_result = try self.isNull(ty, operand);
assert(is_null_result.compare_flags_unsigned == .eq);
return MCValue{ .compare_flags_unsigned = .neq };
}
fn isErr(self: *Self, operand: MCValue) !MCValue {
@ -2364,9 +2374,14 @@ fn isNonErr(self: *Self, operand: MCValue) !MCValue {
fn airIsNull(self: *Self, inst: Air.Inst.Index) !void {
const un_op = self.air.instructions.items(.data)[inst].un_op;
try self.spillCompareFlagsIfOccupied();
self.compare_flags_inst = inst;
const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
const operand = try self.resolveInst(un_op);
break :result try self.isNull(operand);
const ty = self.air.typeOf(un_op);
break :result try self.isNull(ty, operand);
};
return self.finishAir(inst, result, .{ un_op, .none, .none });
}
@ -2375,6 +2390,7 @@ fn airIsNullPtr(self: *Self, inst: Air.Inst.Index) !void {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
const operand_ptr = try self.resolveInst(un_op);
const ptr_ty = self.air.typeOf(un_op);
const operand: MCValue = blk: {
if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
// The MCValue that holds the pointer can be re-used as the value.
@ -2383,8 +2399,8 @@ fn airIsNullPtr(self: *Self, inst: Air.Inst.Index) !void {
break :blk try self.allocRegOrMem(inst, true);
}
};
try self.load(operand, operand_ptr, self.air.typeOf(un_op));
break :result try self.isNull(operand);
try self.load(operand, operand_ptr, ptr_ty);
break :result try self.isNull(ptr_ty.elemType(), operand);
};
return self.finishAir(inst, result, .{ un_op, .none, .none });
}
@ -2393,7 +2409,8 @@ fn airIsNonNull(self: *Self, inst: Air.Inst.Index) !void {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
const operand = try self.resolveInst(un_op);
break :result try self.isNonNull(operand);
const ty = self.air.typeOf(un_op);
break :result try self.isNonNull(ty, operand);
};
return self.finishAir(inst, result, .{ un_op, .none, .none });
}
@ -2402,6 +2419,7 @@ fn airIsNonNullPtr(self: *Self, inst: Air.Inst.Index) !void {
const un_op = self.air.instructions.items(.data)[inst].un_op;
const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
const operand_ptr = try self.resolveInst(un_op);
const ptr_ty = self.air.typeOf(un_op);
const operand: MCValue = blk: {
if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
// The MCValue that holds the pointer can be re-used as the value.
@ -2410,8 +2428,8 @@ fn airIsNonNullPtr(self: *Self, inst: Air.Inst.Index) !void {
break :blk try self.allocRegOrMem(inst, true);
}
};
try self.load(operand, operand_ptr, self.air.typeOf(un_op));
break :result try self.isNonNull(operand);
try self.load(operand, operand_ptr, ptr_ty);
break :result try self.isNonNull(ptr_ty.elemType(), operand);
};
return self.finishAir(inst, result, .{ un_op, .none, .none });
}

20
test/stage2/arm.zig
View File

@ -568,4 +568,24 @@ pub fn addCases(ctx: *TestContext) !void {
"",
);
}
{
var case = ctx.exe("optionals", linux_arm);
case.addCompareOutput(
\\var x: u32 = 42;
\\
\\pub fn main() void {
\\ var p: ?*u32 = null;
\\ assert(p == null);
\\ p = &x;
\\ assert(p != null);
\\}
\\
\\fn assert(ok: bool) void {
\\ if (!ok) unreachable;
\\}
,
"",
);
}
}