Commit 61844b6bd4

joachimschmidt557 <joachim.schmidt557@outlook.com>
2022-06-07 11:08:45
stage2 AArch64: introduce MCValue.condition_flags
Follows 9747303d16dfca61316a292d1e05ac901191e3a3 for AArch64
1 parent 70dc910
Changed files (1)
src
arch
aarch64
src/arch/aarch64/CodeGen.zig
@@ -35,6 +35,7 @@ const RegisterManager = abi.RegisterManager;
 const RegisterLock = RegisterManager.RegisterLock;
 const Register = bits.Register;
 const Instruction = bits.Instruction;
+const Condition = bits.Instruction.Condition;
 const callee_preserved_regs = abi.callee_preserved_regs;
 const c_abi_int_param_regs = abi.c_abi_int_param_regs;
 const c_abi_int_return_regs = abi.c_abi_int_return_regs;
@@ -90,7 +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
-compare_flags_inst: ?Air.Inst.Index = null,
+condition_flags_inst: ?Air.Inst.Index = null,
 
 /// Offset from the stack base, representing the end of the stack frame.
 max_end_stack: u32 = 0,
@@ -161,12 +162,10 @@ const MCValue = union(enum) {
     /// The value is a pointer to one of the stack variables (payload
     /// is stack offset).
     ptr_stack_offset: u32,
-    /// The value is in the compare flags assuming an unsigned
-    /// operation, with this operator applied on top of it.
-    compare_flags_unsigned: math.CompareOperator,
-    /// The value is in the compare flags assuming a signed operation,
-    /// with this operator applied on top of it.
-    compare_flags_signed: math.CompareOperator,
+    /// 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,
 
     fn isMemory(mcv: MCValue) bool {
         return switch (mcv) {
@@ -190,8 +189,7 @@ const MCValue = union(enum) {
 
             .immediate,
             .memory,
-            .compare_flags_unsigned,
-            .compare_flags_signed,
+            .condition_flags,
             .ptr_stack_offset,
             .undef,
             => false,
@@ -758,10 +756,10 @@ fn processDeath(self: *Self, inst: Air.Inst.Index) void {
         },
         .register_with_overflow => |rwo| {
             self.register_manager.freeReg(rwo.reg);
-            self.compare_flags_inst = null;
+            self.condition_flags_inst = null;
         },
-        .compare_flags_signed, .compare_flags_unsigned => {
-            self.compare_flags_inst = null;
+        .condition_flags => {
+            self.condition_flags_inst = null;
         },
         else => {}, // TODO process stack allocation death
     }
@@ -911,12 +909,10 @@ 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.compare_flags_inst) |inst_to_save| {
+    if (self.condition_flags_inst) |inst_to_save| {
         const mcv = self.getResolvedInstValue(inst_to_save);
         const new_mcv = switch (mcv) {
-            .compare_flags_signed,
-            .compare_flags_unsigned,
-            => try self.allocRegOrMem(inst_to_save, true),
+            .condition_flags => try self.allocRegOrMem(inst_to_save, true),
             .register_with_overflow => try self.allocRegOrMem(inst_to_save, false),
             else => unreachable, // mcv doesn't occupy the compare flags
         };
@@ -927,7 +923,7 @@ 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.compare_flags_inst = null;
+        self.condition_flags_inst = null;
 
         // TODO consolidate with register manager and spillInstruction
         // this call should really belong in the register manager!
@@ -1109,32 +1105,7 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
         switch (operand) {
             .dead => unreachable,
             .unreach => unreachable,
-            .compare_flags_unsigned => |op| {
-                const r = MCValue{
-                    .compare_flags_unsigned = switch (op) {
-                        .gte => .lt,
-                        .gt => .lte,
-                        .neq => .eq,
-                        .lt => .gte,
-                        .lte => .gt,
-                        .eq => .neq,
-                    },
-                };
-                break :result r;
-            },
-            .compare_flags_signed => |op| {
-                const r = MCValue{
-                    .compare_flags_signed = switch (op) {
-                        .gte => .lt,
-                        .gt => .lte,
-                        .neq => .eq,
-                        .lt => .gte,
-                        .lte => .gt,
-                        .eq => .neq,
-                    },
-                };
-                break :result r;
-            },
+            .condition_flags => |cond| break :result MCValue{ .condition_flags = cond.negate() },
             else => {
                 switch (operand_ty.zigTypeTag()) {
                     .Bool => {
@@ -1851,7 +1822,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         const stack_offset = try self.allocMem(inst, tuple_size, tuple_align);
 
                         try self.spillCompareFlagsIfOccupied();
-                        self.compare_flags_inst = null;
+                        self.condition_flags_inst = null;
 
                         const base_tag: Air.Inst.Tag = switch (tag) {
                             .add_with_overflow => .add,
@@ -1875,7 +1846,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         _ = try self.binOp(.cmp_eq, dest, .{ .register = truncated_reg }, Type.usize, Type.usize, null);
 
                         try self.genSetStack(lhs_ty, stack_offset, .{ .register = truncated_reg });
-                        try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .compare_flags_unsigned = .neq });
+                        try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
 
                         break :result MCValue{ .stack_offset = stack_offset };
                     },
@@ -1907,7 +1878,7 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         };
 
                         try self.spillCompareFlagsIfOccupied();
-                        self.compare_flags_inst = inst;
+                        self.condition_flags_inst = inst;
 
                         const dest = blk: {
                             if (rhs_immediate_ok) {
@@ -1966,7 +1937,7 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     const stack_offset = try self.allocMem(inst, tuple_size, tuple_align);
 
                     try self.spillCompareFlagsIfOccupied();
-                    self.compare_flags_inst = null;
+                    self.condition_flags_inst = null;
 
                     const base_tag: Mir.Inst.Tag = switch (int_info.signedness) {
                         .signed => .smull,
@@ -2015,16 +1986,14 @@ 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, .{
-                        .compare_flags_unsigned = .neq,
-                    });
+                    try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
 
                     break :result MCValue{ .stack_offset = stack_offset };
                 } else if (int_info.bits <= 64) {
                     const stack_offset = try self.allocMem(inst, tuple_size, tuple_align);
 
                     try self.spillCompareFlagsIfOccupied();
-                    self.compare_flags_inst = null;
+                    self.condition_flags_inst = null;
 
                     // TODO this should really be put in a helper similar to `binOpRegister`
                     const lhs_is_register = lhs == .register;
@@ -2194,9 +2163,7 @@ 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, .{
-                        .compare_flags_unsigned = .neq,
-                    });
+                    try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
 
                     break :result MCValue{ .stack_offset = stack_offset };
                 } else return self.fail("TODO implement mul_with_overflow for integers > u64/i64", .{});
@@ -2236,7 +2203,7 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     try self.spillCompareFlagsIfOccupied();
-                    self.compare_flags_inst = null;
+                    self.condition_flags_inst = null;
 
                     // lsl dest, lhs, rhs
                     const dest = try self.binOp(.shl, lhs, rhs, lhs_ty, rhs_ty, null);
@@ -2251,9 +2218,7 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     _ = try self.binOp(.cmp_eq, lhs, reconstructed, lhs_ty, lhs_ty, null);
 
                     try self.genSetStack(lhs_ty, stack_offset, dest);
-                    try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{
-                        .compare_flags_unsigned = .neq,
-                    });
+                    try self.genSetStack(Type.initTag(.u1), stack_offset - overflow_bit_offset, .{ .condition_flags = .ne });
 
                     break :result MCValue{ .stack_offset = stack_offset };
                 } else {
@@ -2681,8 +2646,7 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
         .undef => unreachable,
         .unreach => unreachable,
         .dead => unreachable,
-        .compare_flags_unsigned,
-        .compare_flags_signed,
+        .condition_flags,
         .register_with_overflow,
         => unreachable, // cannot hold an address
         .immediate => |imm| try self.setRegOrMem(elem_ty, dst_mcv, .{ .memory = imm }),
@@ -2694,7 +2658,7 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
             switch (dst_mcv) {
                 .dead => unreachable,
                 .undef => unreachable,
-                .compare_flags_signed, .compare_flags_unsigned => unreachable,
+                .condition_flags => unreachable,
                 .register => |dst_reg| {
                     try self.genLdrRegister(dst_reg, addr_reg, elem_ty);
                 },
@@ -2903,8 +2867,7 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
         .undef => unreachable,
         .unreach => unreachable,
         .dead => unreachable,
-        .compare_flags_unsigned,
-        .compare_flags_signed,
+        .condition_flags,
         .register_with_overflow,
         => unreachable, // cannot hold an address
         .immediate => |imm| {
@@ -3370,11 +3333,11 @@ fn airCmp(self: *Self, inst: Air.Inst.Index, op: math.CompareOperator) !void {
             });
 
             try self.spillCompareFlagsIfOccupied();
-            self.compare_flags_inst = inst;
+            self.condition_flags_inst = inst;
 
             break :result switch (int_info.signedness) {
-                .signed => MCValue{ .compare_flags_signed = op },
-                .unsigned => MCValue{ .compare_flags_unsigned = op },
+                .signed => MCValue{ .condition_flags = Condition.fromCompareOperatorSigned(op) },
+                .unsigned => MCValue{ .condition_flags = Condition.fromCompareOperatorUnsigned(op) },
             };
         } else {
             return self.fail("TODO AArch64 cmp for ints > 64 bits", .{});
@@ -3434,26 +3397,13 @@ fn airDbgVar(self: *Self, inst: Air.Inst.Index) !void {
 
 fn condBr(self: *Self, condition: MCValue) !Mir.Inst.Index {
     switch (condition) {
-        .compare_flags_signed,
-        .compare_flags_unsigned,
-        => return try self.addInst(.{
+        .condition_flags => |cond| return try self.addInst(.{
             .tag = .b_cond,
             .data = .{
                 .inst_cond = .{
                     .inst = undefined, // populated later through performReloc
-                    .cond = switch (condition) {
-                        .compare_flags_signed => |cmp_op| blk: {
-                            // Here we map to the opposite condition because the jump is to the false branch.
-                            const condition_code = Instruction.Condition.fromCompareOperatorSigned(cmp_op);
-                            break :blk condition_code.negate();
-                        },
-                        .compare_flags_unsigned => |cmp_op| blk: {
-                            // Here we map to the opposite condition because the jump is to the false branch.
-                            const condition_code = Instruction.Condition.fromCompareOperatorUnsigned(cmp_op);
-                            break :blk condition_code.negate();
-                        },
-                        else => unreachable,
-                    },
+                    // Here we map to the opposite condition because the jump is to the false branch.
+                    .cond = cond.negate(),
                 },
             },
         }),
@@ -3503,7 +3453,7 @@ 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_compare_flags_inst = self.compare_flags_inst;
+    const parent_condition_flags_inst = self.condition_flags_inst;
 
     try self.branch_stack.append(.{});
     errdefer {
@@ -3522,7 +3472,7 @@ fn airCondBr(self: *Self, inst: Air.Inst.Index) !void {
     defer saved_then_branch.deinit(self.gpa);
 
     self.register_manager.registers = parent_registers;
-    self.compare_flags_inst = parent_compare_flags_inst;
+    self.condition_flags_inst = parent_condition_flags_inst;
 
     self.stack.deinit(self.gpa);
     self.stack = parent_stack;
@@ -3672,15 +3622,15 @@ fn isErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
         else => return self.fail("TODO implement isErr for {}", .{operand}),
     }
 
-    return MCValue{ .compare_flags_unsigned = .gt };
+    return MCValue{ .condition_flags = .hi };
 }
 
 fn isNonErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
     const is_err_result = try self.isErr(ty, operand);
     switch (is_err_result) {
-        .compare_flags_unsigned => |op| {
-            assert(op == .gt);
-            return MCValue{ .compare_flags_unsigned = .lte };
+        .condition_flags => |cond| {
+            assert(cond == .hi);
+            return MCValue{ .condition_flags = cond.negate() };
         },
         .immediate => |imm| {
             assert(imm == 0);
@@ -3889,7 +3839,7 @@ 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 => blk: {
+                .immediate, .condition_flags => blk: {
                     const new_mcv = try self.allocRegOrMem(block, true);
                     try self.setRegOrMem(self.air.typeOfIndex(block), new_mcv, operand_mcv);
                     break :blk new_mcv;
@@ -4072,8 +4022,7 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
                 else => return self.fail("TODO implement memset", .{}),
             }
         },
-        .compare_flags_unsigned,
-        .compare_flags_signed,
+        .condition_flags,
         .immediate,
         .ptr_stack_offset,
         => {
@@ -4235,15 +4184,7 @@ fn genSetReg(self: *Self, ty: Type, reg: Register, mcv: MCValue) InnerError!void
                 } },
             });
         },
-        .compare_flags_unsigned,
-        .compare_flags_signed,
-        => |op| {
-            const condition = switch (mcv) {
-                .compare_flags_unsigned => Instruction.Condition.fromCompareOperatorUnsigned(op),
-                .compare_flags_signed => Instruction.Condition.fromCompareOperatorSigned(op),
-                else => unreachable,
-            };
-
+        .condition_flags => |condition| {
             _ = try self.addInst(.{
                 .tag = .cset,
                 .data = .{ .r_cond = .{