mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-01-20 14:25:16 +00:00
Code Issues Packages Projects Releases Wiki Activity

stage2 AArch64: implement basic switch statements

Browse Source
This commit is contained in:
joachimschmidt557 2022-10-23 16:53:44 +02:00
parent d2a5a36cab
commit 3ecec50f0c
No known key found for this signature in database
GPG Key ID: E0B575BE2884ACC5
2 changed files with 190 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

226
src/arch/aarch64/CodeGen.zig
View File

@ -91,7 +91,7 @@ register_manager: RegisterManager = .{},
/// Maps offset to what is stored there.
stack: std.AutoHashMapUnmanaged(u32, StackAllocation) = .{},
/// Tracks the current instruction allocated to the compare flags
condition_flags_inst: ?Air.Inst.Index = null,
compare_flags_inst: ?Air.Inst.Index = null,
/// Offset from the stack base, representing the end of the stack frame.
max_end_stack: u32 = 0,
@ -154,7 +154,7 @@ const MCValue = union(enum) {
/// The value resides in the N, Z, C, V flags. The value is 1 (if
/// the type is u1) or true (if the type in bool) iff the
/// specified condition is true.
condition_flags: Condition,
compare_flags: Condition,
/// The value is a function argument passed via the stack.
stack_argument_offset: u32,
};
@ -201,6 +201,29 @@ const BigTomb = struct {
log.debug("%{d} => {}", .{ bt.inst, result });
const branch = &bt.function.branch_stack.items[bt.function.branch_stack.items.len - 1];
branch.inst_table.putAssumeCapacityNoClobber(bt.inst, result);
switch (result) {
.register => |reg| {
// In some cases (such as bitcast), an operand
// may be the same MCValue as the result. If
// that operand died and was a register, it
// was freed by processDeath. We have to
// "re-allocate" the register.
if (bt.function.register_manager.isRegFree(reg)) {
bt.function.register_manager.getRegAssumeFree(reg, bt.inst);
}
},
.register_with_overflow => |rwo| {
if (bt.function.register_manager.isRegFree(rwo.reg)) {
bt.function.register_manager.getRegAssumeFree(rwo.reg, bt.inst);
}
bt.function.compare_flags_inst = bt.inst;
},
.compare_flags => |_| {
bt.function.compare_flags_inst = bt.inst;
},
else => {},
}
}
bt.function.finishAirBookkeeping();
}
@ -764,10 +787,10 @@ fn processDeath(self: *Self, inst: Air.Inst.Index) void {
},
.register_with_overflow => |rwo| {
self.register_manager.freeReg(rwo.reg);
self.condition_flags_inst = null;
self.compare_flags_inst = null;
},
.condition_flags => {
self.condition_flags_inst = null;
.compare_flags => {
self.compare_flags_inst = null;
},
else => {}, // TODO process stack allocation death
}
@ -808,6 +831,15 @@ fn finishAir(self: *Self, inst: Air.Inst.Index, result: MCValue, operands: [Live
self.register_manager.getRegAssumeFree(reg, inst);
}
},
.register_with_overflow => |rwo| {
if (self.register_manager.isRegFree(rwo.reg)) {
self.register_manager.getRegAssumeFree(rwo.reg, inst);
}
self.compare_flags_inst = inst;
},
.compare_flags => |_| {
self.compare_flags_inst = inst;
},
else => {},
}
}
@ -931,11 +963,11 @@ pub fn spillInstruction(self: *Self, reg: Register, inst: Air.Inst.Index) !void
/// Save the current instruction stored in the compare flags if
/// occupied
fn spillCompareFlagsIfOccupied(self: *Self) !void {
if (self.condition_flags_inst) |inst_to_save| {
if (self.compare_flags_inst) |inst_to_save| {
const ty = self.air.typeOfIndex(inst_to_save);
const mcv = self.getResolvedInstValue(inst_to_save);
const new_mcv = switch (mcv) {
.condition_flags => try self.allocRegOrMem(ty, true, inst_to_save),
.compare_flags => try self.allocRegOrMem(ty, true, inst_to_save),
.register_with_overflow => try self.allocRegOrMem(ty, false, inst_to_save),
else => unreachable, // mcv doesn't occupy the compare flags
};
@ -946,7 +978,7 @@ fn spillCompareFlagsIfOccupied(self: *Self) !void {
const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
try branch.inst_table.put(self.gpa, inst_to_save, new_mcv);
self.condition_flags_inst = null;
self.compare_flags_inst = null;
// TODO consolidate with register manager and spillInstruction
// this call should really belong in the register manager!
@ -1155,7 +1187,7 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
switch (operand) {
.dead => unreachable,
.unreach => unreachable,
.condition_flags => |cond| break :result MCValue{ .condition_flags = cond.negate() },
.compare_flags => |cond| break :result MCValue{ .compare_flags = cond.negate() },
else => {
switch (operand_ty.zigTypeTag()) {
.Bool => {
@ -1564,9 +1596,9 @@ fn allocRegs(
// If the previous MCValue occupied some space we track, we
// need to make sure it is marked as free now.
switch (mcv) {
.condition_flags => {
assert(self.condition_flags_inst.? == inst);
self.condition_flags_inst = null;
.compare_flags => {
assert(self.compare_flags_inst.? == inst);
self.compare_flags_inst = null;
},
.register => |prev_reg| {
assert(!self.register_manager.isRegFree(prev_reg));
@ -2363,7 +2395,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
const stack_offset = try self.allocMem(tuple_size, tuple_align, inst);
try self.spillCompareFlagsIfOccupied();
self.condition_flags_inst = null;
self.compare_flags_inst = null;
const base_tag: Air.Inst.Tag = switch (tag) {
.add_with_overflow => .add,
@ -2395,7 +2427,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
});
try self.genSetStack(lhs_ty, stack_offset, .{ .register = truncated_reg });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .compare_flags = .ne });
break :result MCValue{ .stack_offset = stack_offset };
},
@ -2430,7 +2462,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
};
try self.spillCompareFlagsIfOccupied();
self.condition_flags_inst = inst;
self.compare_flags_inst = inst;
const dest = blk: {
if (rhs_immediate_ok) {
@ -2539,7 +2571,7 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
}
try self.genSetStack(lhs_ty, stack_offset, .{ .register = truncated_reg });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .compare_flags = .ne });
break :result MCValue{ .stack_offset = stack_offset };
} else if (int_info.bits <= 64) {
@ -2679,7 +2711,7 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
try self.truncRegister(dest_reg, truncated_reg, int_info.signedness, int_info.bits);
try self.genSetStack(lhs_ty, stack_offset, .{ .register = truncated_reg });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .compare_flags = .ne });
break :result MCValue{ .stack_offset = stack_offset };
} else return self.fail("TODO implement mul_with_overflow for integers > u64/i64", .{});
@ -2811,7 +2843,7 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
});
try self.genSetStack(lhs_ty, stack_offset, .{ .register = dest_reg });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .compare_flags = .ne });
break :result MCValue{ .stack_offset = stack_offset };
} else {
@ -3262,7 +3294,7 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
.undef => unreachable,
.unreach => unreachable,
.dead => unreachable,
.condition_flags,
.compare_flags,
.register_with_overflow,
=> unreachable, // cannot hold an address
.immediate => |imm| try self.setRegOrMem(elem_ty, dst_mcv, .{ .memory = imm }),
@ -3274,7 +3306,7 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
switch (dst_mcv) {
.dead => unreachable,
.undef => unreachable,
.condition_flags => unreachable,
.compare_flags => unreachable,
.register => |dst_reg| {
try self.genLdrRegister(dst_reg, addr_reg, elem_ty);
},
@ -3483,7 +3515,7 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
.undef => unreachable,
.unreach => unreachable,
.dead => unreachable,
.condition_flags,
.compare_flags,
.register_with_overflow,
=> unreachable, // cannot hold an address
.immediate => |imm| {
@ -3638,7 +3670,7 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
0 => MCValue{ .register = rwo.reg },
// get overflow bit: return C or V flag
1 => MCValue{ .condition_flags = rwo.flag },
1 => MCValue{ .compare_flags = rwo.flag },
else => unreachable,
};
@ -4092,8 +4124,8 @@ fn cmp(
}
return switch (int_info.signedness) {
.signed => MCValue{ .condition_flags = Condition.fromCompareOperatorSigned(op) },
.unsigned => MCValue{ .condition_flags = Condition.fromCompareOperatorUnsigned(op) },
.signed => MCValue{ .compare_flags = Condition.fromCompareOperatorSigned(op) },
.unsigned => MCValue{ .compare_flags = Condition.fromCompareOperatorUnsigned(op) },
};
} else {
return self.fail("TODO AArch64 cmp for ints > 64 bits", .{});
@ -4151,7 +4183,7 @@ fn airDbgVar(self: *Self, inst: Air.Inst.Index) !void {
fn condBr(self: *Self, condition: MCValue) !Mir.Inst.Index {
switch (condition) {
.condition_flags => |cond| return try self.addInst(.{
.compare_flags => |cond| return try self.addInst(.{
.tag = .b_cond,
.data = .{
.inst_cond = .{
@ -4207,7 +4239,7 @@ fn airCondBr(self: *Self, inst: Air.Inst.Index) !void {
var parent_stack = try self.stack.clone(self.gpa);
defer parent_stack.deinit(self.gpa);
const parent_registers = self.register_manager.registers;
const parent_condition_flags_inst = self.condition_flags_inst;
const parent_compare_flags_inst = self.compare_flags_inst;
try self.branch_stack.append(.{});
errdefer {
@ -4226,7 +4258,7 @@ fn airCondBr(self: *Self, inst: Air.Inst.Index) !void {
defer saved_then_branch.deinit(self.gpa);
self.register_manager.registers = parent_registers;
self.condition_flags_inst = parent_condition_flags_inst;
self.compare_flags_inst = parent_compare_flags_inst;
self.stack.deinit(self.gpa);
self.stack = parent_stack;
@ -4354,9 +4386,9 @@ fn isErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
fn isNonErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
const is_err_result = try self.isErr(ty, operand);
switch (is_err_result) {
.condition_flags => |cond| {
.compare_flags => |cond| {
assert(cond == .hi);
return MCValue{ .condition_flags = cond.negate() };
return MCValue{ .compare_flags = cond.negate() };
},
.immediate => |imm| {
assert(imm == 0);
@ -4519,10 +4551,132 @@ fn airBlock(self: *Self, inst: Air.Inst.Index) !void {
fn airSwitch(self: *Self, inst: Air.Inst.Index) !void {
const pl_op = self.air.instructions.items(.data)[inst].pl_op;
const condition = pl_op.operand;
_ = condition;
const condition_ty = self.air.typeOf(pl_op.operand);
const switch_br = self.air.extraData(Air.SwitchBr, pl_op.payload);
const liveness = try self.liveness.getSwitchBr(
self.gpa,
inst,
switch_br.data.cases_len + 1,
);
defer self.gpa.free(liveness.deaths);
return self.fail("TODO airSwitch for {}", .{self.target.cpu.arch});
var extra_index: usize = switch_br.end;
var case_i: u32 = 0;
while (case_i < switch_br.data.cases_len) : (case_i += 1) {
const case = self.air.extraData(Air.SwitchBr.Case, extra_index);
const items = @ptrCast([]const Air.Inst.Ref, self.air.extra[case.end..][0..case.data.items_len]);
assert(items.len > 0);
const case_body = self.air.extra[case.end + items.len ..][0..case.data.body_len];
extra_index = case.end + items.len + case_body.len;
// For every item, we compare it to condition and branch into
// the prong if they are equal. After we compared to all
// items, we branch into the next prong (or if no other prongs
// exist out of the switch statement).
//
// cmp condition, item1
// beq prong
// cmp condition, item2
// beq prong
// cmp condition, item3
// beq prong
// b out
// prong: ...
// ...
// out: ...
const branch_into_prong_relocs = try self.gpa.alloc(u32, items.len);
defer self.gpa.free(branch_into_prong_relocs);
for (items) |item, idx| {
const cmp_result = try self.cmp(.{ .inst = pl_op.operand }, .{ .inst = item }, condition_ty, .neq);
branch_into_prong_relocs[idx] = try self.condBr(cmp_result);
}
const branch_away_from_prong_reloc = try self.addInst(.{
.tag = .b,
.data = .{ .inst = undefined }, // populated later through performReloc
});
for (branch_into_prong_relocs) |reloc| {
try self.performReloc(reloc);
}
// Capture the state of register and stack allocation state so that we can revert to it.
const parent_next_stack_offset = self.next_stack_offset;
const parent_free_registers = self.register_manager.free_registers;
const parent_compare_flags_inst = self.compare_flags_inst;
var parent_stack = try self.stack.clone(self.gpa);
defer parent_stack.deinit(self.gpa);
const parent_registers = self.register_manager.registers;
try self.branch_stack.append(.{});
errdefer {
_ = self.branch_stack.pop();
}
try self.ensureProcessDeathCapacity(liveness.deaths[case_i].len);
for (liveness.deaths[case_i]) |operand| {
self.processDeath(operand);
}
try self.genBody(case_body);
// Revert to the previous register and stack allocation state.
var saved_case_branch = self.branch_stack.pop();
defer saved_case_branch.deinit(self.gpa);
self.register_manager.registers = parent_registers;
self.compare_flags_inst = parent_compare_flags_inst;
self.stack.deinit(self.gpa);
self.stack = parent_stack;
parent_stack = .{};
self.next_stack_offset = parent_next_stack_offset;
self.register_manager.free_registers = parent_free_registers;
try self.performReloc(branch_away_from_prong_reloc);
}
if (switch_br.data.else_body_len > 0) {
const else_body = self.air.extra[extra_index..][0..switch_br.data.else_body_len];
// Capture the state of register and stack allocation state so that we can revert to it.
const parent_next_stack_offset = self.next_stack_offset;
const parent_free_registers = self.register_manager.free_registers;
const parent_compare_flags_inst = self.compare_flags_inst;
var parent_stack = try self.stack.clone(self.gpa);
defer parent_stack.deinit(self.gpa);
const parent_registers = self.register_manager.registers;
try self.branch_stack.append(.{});
errdefer {
_ = self.branch_stack.pop();
}
const else_deaths = liveness.deaths.len - 1;
try self.ensureProcessDeathCapacity(liveness.deaths[else_deaths].len);
for (liveness.deaths[else_deaths]) |operand| {
self.processDeath(operand);
}
try self.genBody(else_body);
// Revert to the previous register and stack allocation state.
var saved_case_branch = self.branch_stack.pop();
defer saved_case_branch.deinit(self.gpa);
self.register_manager.registers = parent_registers;
self.compare_flags_inst = parent_compare_flags_inst;
self.stack.deinit(self.gpa);
self.stack = parent_stack;
parent_stack = .{};
self.next_stack_offset = parent_next_stack_offset;
self.register_manager.free_registers = parent_free_registers;
// TODO consolidate returned MCValues between prongs and else branch like we do
// in airCondBr.
}
return self.finishAir(inst, .unreach, .{ pl_op.operand, .none, .none });
}
fn performReloc(self: *Self, inst: Mir.Inst.Index) !void {
@ -4551,7 +4705,7 @@ fn br(self: *Self, block: Air.Inst.Index, operand: Air.Inst.Ref) !void {
block_data.mcv = switch (operand_mcv) {
.none, .dead, .unreach => unreachable,
.register, .stack_offset, .memory => operand_mcv,
.immediate, .stack_argument_offset, .condition_flags => blk: {
.immediate, .stack_argument_offset, .compare_flags => blk: {
const new_mcv = try self.allocRegOrMem(self.air.typeOfIndex(block), true, block);
try self.setRegOrMem(self.air.typeOfIndex(block), new_mcv, operand_mcv);
break :blk new_mcv;
@ -4734,7 +4888,7 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
else => return self.fail("TODO implement memset", .{}),
}
},
.condition_flags,
.compare_flags,
.immediate,
.ptr_stack_offset,
=> {
@ -4894,7 +5048,7 @@ fn genSetReg(self: *Self, ty: Type, reg: Register, mcv: MCValue) InnerError!void
} },
});
},
.condition_flags => |condition| {
.compare_flags => |condition| {
_ = try self.addInst(.{
.tag = .cset,
.data = .{ .r_cond = .{
@ -5171,7 +5325,7 @@ fn genSetStackArgument(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) I
try self.genInlineMemcpy(src_reg, dst_reg, len_reg, count_reg, tmp_reg);
}
},
.condition_flags,
.compare_flags,
.immediate,
.ptr_stack_offset,
=> {

25
test/behavior/switch.zig
View File

@ -5,8 +5,6 @@ const expectError = std.testing.expectError;
const expectEqual = std.testing.expectEqual;
test "switch with numbers" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testSwitchWithNumbers(13);
}
@ -20,8 +18,6 @@ fn testSwitchWithNumbers(x: u32) !void {
}
test "switch with all ranges" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try expect(testSwitchWithAllRanges(50, 3) == 1);
try expect(testSwitchWithAllRanges(101, 0) == 2);
try expect(testSwitchWithAllRanges(300, 5) == 3);
@ -53,8 +49,6 @@ test "implicit comptime switch" {
}
test "switch on enum" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const fruit = Fruit.Orange;
nonConstSwitchOnEnum(fruit);
}
@ -72,8 +66,6 @@ fn nonConstSwitchOnEnum(fruit: Fruit) void {
}
test "switch statement" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try nonConstSwitch(SwitchStatementFoo.C);
}
fn nonConstSwitch(foo: SwitchStatementFoo) !void {
@ -89,7 +81,6 @@ const SwitchStatementFoo = enum { A, B, C, D };
test "switch with multiple expressions" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const x = switch (returnsFive()) {
1, 2, 3 => 1,
@ -103,8 +94,6 @@ fn returnsFive() i32 {
}
test "switch on type" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try expect(trueIfBoolFalseOtherwise(bool));
try expect(!trueIfBoolFalseOtherwise(i32));
}
@ -117,8 +106,6 @@ fn trueIfBoolFalseOtherwise(comptime T: type) bool {
}
test "switching on booleans" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testSwitchOnBools();
comptime try testSwitchOnBools();
}
@ -170,8 +157,6 @@ test "undefined.u0" {
}
test "switch with disjoint range" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
var q: u8 = 0;
switch (q) {
0...125 => {},
@ -214,8 +199,6 @@ fn poll() void {
}
test "switch on global mutable var isn't constant-folded" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
while (state < 2) {
poll();
}
@ -273,7 +256,6 @@ fn testSwitchEnumPtrCapture() !void {
test "switch handles all cases of number" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testSwitchHandleAllCases();
comptime try testSwitchHandleAllCases();
@ -363,8 +345,6 @@ test "anon enum literal used in switch on union enum" {
}
test "switch all prongs unreachable" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testAllProngsUnreachable();
comptime try testAllProngsUnreachable();
}
@ -400,7 +380,6 @@ fn return_a_number() anyerror!i32 {
test "switch on integer with else capturing expr" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const S = struct {
fn doTheTest() !void {
@ -641,8 +620,6 @@ test "switch capture copies its payload" {
}
test "capture of integer forwards the switch condition directly" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const S = struct {
fn foo(x: u8) !void {
switch (x) {
@ -662,8 +639,6 @@ test "capture of integer forwards the switch condition directly" {
}
test "enum value without tag name used as switch item" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const E = enum(u32) {
a = 1,
b = 2,