Commit 197c2a465f

Jakub Konka <kubkon@jakubkonka.com>
2022-05-07 10:46:05
regalloc: rename freeze/unfreeze to lock/unlock registers
master
1 parent 43a6279
Changed files (5)
src
arch
aarch64
CodeGen.zig
arm
CodeGen.zig
riscv64
CodeGen.zig
x86_64
CodeGen.zig
register_manager.zig
src/arch/aarch64/CodeGen.zig
@@ -728,7 +728,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
             // zig fmt: on
         }
 
-        assert(!self.register_manager.frozenRegsExist());
+        assert(!self.register_manager.lockedRegsExist());
 
         if (std.debug.runtime_safety) {
             if (self.air_bookkeeping < old_air_bookkeeping + 1) {
@@ -1058,8 +1058,8 @@ fn trunc(
                 }
             },
         };
-        const lock = self.register_manager.freezeReg(operand_reg);
-        defer if (lock) |reg| self.register_manager.unfreezeReg(reg);
+        const lock = self.register_manager.lockReg(operand_reg);
+        defer if (lock) |reg| self.register_manager.unlockReg(reg);
 
         const dest_reg = if (maybe_inst) |inst| blk: {
             const ty_op = self.air.instructions.items(.data)[inst].ty_op;
@@ -1145,8 +1145,8 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
                             .register => |r| r,
                             else => try self.copyToTmpRegister(operand_ty, operand),
                         };
-                        const reg_lock = self.register_manager.freezeRegAssumeUnused(op_reg);
-                        defer self.register_manager.unfreezeReg(reg_lock);
+                        const reg_lock = self.register_manager.lockRegAssumeUnused(op_reg);
+                        defer self.register_manager.unlockReg(reg_lock);
 
                         const dest_reg = blk: {
                             if (operand == .register and self.reuseOperand(inst, ty_op.operand, 0, operand)) {
@@ -1178,8 +1178,8 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
                                 .register => |r| r,
                                 else => try self.copyToTmpRegister(operand_ty, operand),
                             };
-                            const reg_lock = self.register_manager.freezeRegAssumeUnused(op_reg);
-                            defer self.register_manager.unfreezeReg(reg_lock);
+                            const reg_lock = self.register_manager.lockRegAssumeUnused(op_reg);
+                            defer self.register_manager.unlockReg(reg_lock);
 
                             const dest_reg = blk: {
                                 if (operand == .register and self.reuseOperand(inst, ty_op.operand, 0, operand)) {
@@ -1268,16 +1268,16 @@ fn binOpRegister(
     const rhs_is_register = rhs == .register;
 
     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-        self.register_manager.freezeReg(lhs.register)
+        self.register_manager.lockReg(lhs.register)
     else
         null;
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs_lock: ?RegisterLock = if (rhs_is_register)
-        self.register_manager.freezeReg(rhs.register)
+        self.register_manager.lockReg(rhs.register)
     else
         null;
-    defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
 
@@ -1294,8 +1294,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs_reg = if (rhs_is_register) rhs.register else blk: {
         const track_inst: ?Air.Inst.Index = if (maybe_inst) |inst| inst: {
@@ -1310,8 +1310,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_rhs_lock = self.register_manager.freezeReg(rhs_reg);
-    defer if (new_rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_rhs_lock = self.register_manager.lockReg(rhs_reg);
+    defer if (new_rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dest_reg = switch (mir_tag) {
         .cmp_shifted_register => undefined, // cmp has no destination register
@@ -1414,10 +1414,10 @@ fn binOpImmediate(
     const lhs_is_register = lhs == .register;
 
     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-        self.register_manager.freezeReg(lhs.register)
+        self.register_manager.lockReg(lhs.register)
     else
         null;
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
 
@@ -1436,8 +1436,8 @@ fn binOpImmediate(
 
         break :blk reg;
     };
-    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dest_reg = switch (mir_tag) {
         .cmp_immediate => undefined, // cmp has no destination register
@@ -1841,13 +1841,13 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         };
                         const dest = try self.binOp(base_tag, null, lhs, rhs, lhs_ty, rhs_ty);
                         const dest_reg = dest.register;
-                        const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                        defer self.register_manager.unfreezeReg(dest_reg_lock);
+                        const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                        defer self.register_manager.unlockReg(dest_reg_lock);
 
                         const raw_truncated_reg = try self.register_manager.allocReg(null);
                         const truncated_reg = registerAlias(raw_truncated_reg, lhs_ty.abiSize(self.target.*));
-                        const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                        defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                        const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                        defer self.register_manager.unlockReg(truncated_reg_lock);
 
                         // sbfx/ubfx truncated, dest, #0, #bits
                         try self.truncRegister(dest_reg, truncated_reg, int_info.signedness, int_info.bits);
@@ -1948,12 +1948,12 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
 
                     const dest = try self.binOpRegister(base_tag, null, lhs, rhs, lhs_ty, rhs_ty);
                     const dest_reg = dest.register;
-                    const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                    defer self.register_manager.unfreezeReg(dest_reg_lock);
+                    const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                    defer self.register_manager.unlockReg(dest_reg_lock);
 
                     const truncated_reg = try self.register_manager.allocReg(null);
-                    const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                    defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                    const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                    defer self.register_manager.unlockReg(truncated_reg_lock);
 
                     try self.truncRegister(
                         dest_reg.to32(),
@@ -2004,32 +2004,32 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     const rhs_is_register = rhs == .register;
 
                     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-                        self.register_manager.freezeRegAssumeUnused(lhs.register)
+                        self.register_manager.lockRegAssumeUnused(lhs.register)
                     else
                         null;
-                    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const rhs_lock: ?RegisterLock = if (rhs_is_register)
-                        self.register_manager.freezeRegAssumeUnused(rhs.register)
+                        self.register_manager.lockRegAssumeUnused(rhs.register)
                     else
                         null;
-                    defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const lhs_reg = if (lhs_is_register) lhs.register else blk: {
                         const raw_reg = try self.register_manager.allocReg(null);
                         const reg = registerAlias(raw_reg, lhs_ty.abiSize(self.target.*));
                         break :blk reg;
                     };
-                    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-                    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+                    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const rhs_reg = if (rhs_is_register) rhs.register else blk: {
                         const raw_reg = try self.register_manager.allocReg(null);
                         const reg = registerAlias(raw_reg, rhs_ty.abiAlignment(self.target.*));
                         break :blk reg;
                     };
-                    const new_rhs_lock = self.register_manager.freezeReg(rhs_reg);
-                    defer if (new_rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    const new_rhs_lock = self.register_manager.lockReg(rhs_reg);
+                    defer if (new_rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     if (!lhs_is_register) try self.genSetReg(lhs_ty, lhs_reg, lhs);
                     if (!rhs_is_register) try self.genSetReg(rhs_ty, rhs_reg, rhs);
@@ -2039,8 +2039,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         const reg = registerAlias(raw_reg, lhs_ty.abiSize(self.target.*));
                         break :blk reg;
                     };
-                    const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                    defer self.register_manager.unfreezeReg(dest_reg_lock);
+                    const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                    defer self.register_manager.unlockReg(dest_reg_lock);
 
                     switch (int_info.signedness) {
                         .signed => {
@@ -2055,8 +2055,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                             });
 
                             const dest_high_reg = try self.register_manager.allocReg(null);
-                            const dest_high_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_high_reg);
-                            defer self.register_manager.unfreezeReg(dest_high_reg_lock);
+                            const dest_high_reg_lock = self.register_manager.lockRegAssumeUnused(dest_high_reg);
+                            defer self.register_manager.unlockReg(dest_high_reg_lock);
 
                             // smulh dest_high, lhs, rhs
                             _ = try self.addInst(.{
@@ -2105,8 +2105,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         },
                         .unsigned => {
                             const dest_high_reg = try self.register_manager.allocReg(null);
-                            const dest_high_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_high_reg);
-                            defer self.register_manager.unfreezeReg(dest_high_reg_lock);
+                            const dest_high_reg_lock = self.register_manager.lockRegAssumeUnused(dest_high_reg);
+                            defer self.register_manager.unlockReg(dest_high_reg_lock);
 
                             // umulh dest_high, lhs, rhs
                             _ = try self.addInst(.{
@@ -2161,8 +2161,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     }
 
                     const truncated_reg = try self.register_manager.allocReg(null);
-                    const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                    defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                    const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                    defer self.register_manager.unlockReg(truncated_reg_lock);
 
                     try self.truncRegister(dest_reg, truncated_reg, int_info.signedness, int_info.bits);
 
@@ -2203,10 +2203,10 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     const stack_offset = try self.allocMem(inst, tuple_size, tuple_align);
 
                     const lhs_lock: ?RegisterLock = if (lhs == .register)
-                        self.register_manager.freezeRegAssumeUnused(lhs.register)
+                        self.register_manager.lockRegAssumeUnused(lhs.register)
                     else
                         null;
-                    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     try self.spillCompareFlagsIfOccupied();
                     self.compare_flags_inst = null;
@@ -2214,8 +2214,8 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     // lsl dest, lhs, rhs
                     const dest = try self.binOp(.shl, null, lhs, rhs, lhs_ty, rhs_ty);
                     const dest_reg = dest.register;
-                    const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                    defer self.register_manager.unfreezeReg(dest_reg_lock);
+                    const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                    defer self.register_manager.unlockReg(dest_reg_lock);
 
                     // asr/lsr reconstructed, dest, rhs
                     const reconstructed = try self.binOp(.shr, null, dest, rhs, lhs_ty, rhs_ty);
@@ -2454,17 +2454,17 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
         const slice_ptr_field_type = slice_ty.slicePtrFieldType(&buf);
 
         const index_lock: ?RegisterLock = if (index_is_register)
-            self.register_manager.freezeRegAssumeUnused(index_mcv.register)
+            self.register_manager.lockRegAssumeUnused(index_mcv.register)
         else
             null;
-        defer if (index_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (index_lock) |reg| self.register_manager.unlockReg(reg);
 
         const base_mcv: MCValue = switch (slice_mcv) {
             .stack_offset => |off| .{ .register = try self.copyToTmpRegister(slice_ptr_field_type, .{ .stack_offset = off }) },
             else => return self.fail("TODO slice_elem_val when slice is {}", .{slice_mcv}),
         };
-        const base_lock = self.register_manager.freezeRegAssumeUnused(base_mcv.register);
-        defer self.register_manager.unfreezeReg(base_lock);
+        const base_lock = self.register_manager.lockRegAssumeUnused(base_mcv.register);
+        defer self.register_manager.unlockReg(base_lock);
 
         switch (elem_size) {
             else => {
@@ -2605,8 +2605,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
         .immediate => |imm| try self.setRegOrMem(elem_ty, dst_mcv, .{ .memory = imm }),
         .ptr_stack_offset => |off| try self.setRegOrMem(elem_ty, dst_mcv, .{ .stack_offset = off }),
         .register => |addr_reg| {
-            const addr_reg_lock = self.register_manager.freezeReg(addr_reg);
-            defer if (addr_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+            const addr_reg_lock = self.register_manager.lockReg(addr_reg);
+            defer if (addr_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
             switch (dst_mcv) {
                 .dead => unreachable,
@@ -2619,8 +2619,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
                     if (elem_size <= 8) {
                         const raw_tmp_reg = try self.register_manager.allocReg(null);
                         const tmp_reg = registerAlias(raw_tmp_reg, elem_size);
-                        const tmp_reg_lock = self.register_manager.freezeRegAssumeUnused(tmp_reg);
-                        defer self.register_manager.unfreezeReg(tmp_reg_lock);
+                        const tmp_reg_lock = self.register_manager.lockRegAssumeUnused(tmp_reg);
+                        defer self.register_manager.unlockReg(tmp_reg_lock);
 
                         try self.load(.{ .register = tmp_reg }, ptr, ptr_ty);
                         try self.genSetStack(elem_ty, off, MCValue{ .register = tmp_reg });
@@ -2628,9 +2628,9 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
                         // TODO optimize the register allocation
                         const regs = try self.register_manager.allocRegs(4, .{ null, null, null, null });
                         var regs_locks: [4]RegisterLock = undefined;
-                        self.register_manager.freezeRegsAssumeUnused(4, regs, &regs_locks);
+                        self.register_manager.lockRegsAssumeUnused(4, regs, &regs_locks);
                         defer for (regs_locks) |reg| {
-                            self.register_manager.unfreezeReg(reg);
+                            self.register_manager.unlockReg(reg);
                         };
 
                         const src_reg = addr_reg;
@@ -2833,8 +2833,8 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
             try self.genSetStack(value_ty, off, value);
         },
         .register => |addr_reg| {
-            const addr_reg_lock = self.register_manager.freezeReg(addr_reg);
-            defer if (addr_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+            const addr_reg_lock = self.register_manager.lockReg(addr_reg);
+            defer if (addr_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
             switch (value) {
                 .register => |value_reg| {
@@ -2844,8 +2844,8 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
                     if (abi_size <= 8) {
                         const raw_tmp_reg = try self.register_manager.allocReg(null);
                         const tmp_reg = registerAlias(raw_tmp_reg, abi_size);
-                        const tmp_reg_lock = self.register_manager.freezeRegAssumeUnused(tmp_reg);
-                        defer self.register_manager.unfreezeReg(tmp_reg_lock);
+                        const tmp_reg_lock = self.register_manager.lockRegAssumeUnused(tmp_reg);
+                        defer self.register_manager.unlockReg(tmp_reg_lock);
 
                         try self.genSetReg(value_ty, tmp_reg, value);
                         try self.store(ptr, .{ .register = tmp_reg }, ptr_ty, value_ty);
@@ -2905,12 +2905,12 @@ fn structFieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, inde
                 const offset_reg = try self.copyToTmpRegister(ptr_ty, .{
                     .immediate = struct_field_offset,
                 });
-                const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-                defer self.register_manager.unfreezeReg(offset_reg_lock);
+                const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+                defer self.register_manager.unlockReg(offset_reg_lock);
 
                 const addr_reg = try self.copyToTmpRegister(ptr_ty, mcv);
-                const addr_reg_lock = self.register_manager.freezeRegAssumeUnused(addr_reg);
-                defer self.register_manager.unfreezeReg(addr_reg_lock);
+                const addr_reg_lock = self.register_manager.lockRegAssumeUnused(addr_reg);
+                defer self.register_manager.unlockReg(addr_reg_lock);
 
                 const dest = try self.binOp(
                     .add,
@@ -4008,8 +4008,8 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
         .register_c_flag,
         .register_v_flag,
         => |reg| {
-            const reg_lock = self.register_manager.freezeReg(reg);
-            defer if (reg_lock) |locked_reg| self.register_manager.unfreezeReg(locked_reg);
+            const reg_lock = self.register_manager.lockReg(reg);
+            defer if (reg_lock) |locked_reg| self.register_manager.unlockReg(locked_reg);
 
             const wrapped_ty = ty.structFieldType(0);
             try self.genSetStack(wrapped_ty, stack_offset, .{ .register = reg });
@@ -4066,9 +4066,9 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
                 // TODO call extern memcpy
                 const regs = try self.register_manager.allocRegs(5, .{ null, null, null, null, null });
                 var regs_locks: [5]RegisterLock = undefined;
-                self.register_manager.freezeRegsAssumeUnused(5, regs, &regs_locks);
+                self.register_manager.lockRegsAssumeUnused(5, regs, &regs_locks);
                 defer for (regs_locks) |reg| {
-                    self.register_manager.unfreezeReg(reg);
+                    self.register_manager.unlockReg(reg);
                 };
 
                 const src_reg = regs[0];
src/arch/arm/CodeGen.zig
@@ -735,7 +735,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
             // zig fmt: on
         }
 
-        assert(!self.register_manager.frozenRegsExist());
+        assert(!self.register_manager.lockedRegsExist());
 
         if (std.debug.runtime_safety) {
             if (self.air_bookkeeping < old_air_bookkeeping + 1) {
@@ -1039,8 +1039,8 @@ fn trunc(
                 }
             },
         };
-        const operand_reg_lock = self.register_manager.freezeReg(operand_reg);
-        defer if (operand_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+        const operand_reg_lock = self.register_manager.lockReg(operand_reg);
+        defer if (operand_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
         const dest_reg = if (maybe_inst) |inst| blk: {
             const ty_op = self.air.instructions.items(.data)[inst].ty_op;
@@ -1128,8 +1128,8 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
                             .register => |r| r,
                             else => try self.copyToTmpRegister(operand_ty, operand),
                         };
-                        const op_reg_lock = self.register_manager.freezeRegAssumeUnused(op_reg);
-                        defer self.register_manager.unfreezeReg(op_reg_lock);
+                        const op_reg_lock = self.register_manager.lockRegAssumeUnused(op_reg);
+                        defer self.register_manager.unlockReg(op_reg_lock);
 
                         const dest_reg = blk: {
                             if (operand == .register and self.reuseOperand(inst, ty_op.operand, 0, operand)) {
@@ -1158,8 +1158,8 @@ fn airNot(self: *Self, inst: Air.Inst.Index) !void {
                                 .register => |r| r,
                                 else => try self.copyToTmpRegister(operand_ty, operand),
                             };
-                            const op_reg_lock = self.register_manager.freezeRegAssumeUnused(op_reg);
-                            defer self.register_manager.unfreezeReg(op_reg_lock);
+                            const op_reg_lock = self.register_manager.lockRegAssumeUnused(op_reg);
+                            defer self.register_manager.unlockReg(op_reg_lock);
 
                             const dest_reg = blk: {
                                 if (operand == .register and self.reuseOperand(inst, ty_op.operand, 0, operand)) {
@@ -1219,15 +1219,15 @@ fn minMax(
                     .register => |r| r,
                     else => try self.copyToTmpRegister(lhs_ty, lhs),
                 };
-                const lhs_reg_lock = self.register_manager.freezeReg(lhs_reg);
-                defer if (lhs_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+                const lhs_reg_lock = self.register_manager.lockReg(lhs_reg);
+                defer if (lhs_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
                 const rhs_reg = switch (rhs) {
                     .register => |r| r,
                     else => try self.copyToTmpRegister(rhs_ty, rhs),
                 };
-                const rhs_reg_lock = self.register_manager.freezeReg(rhs_reg);
-                defer if (rhs_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+                const rhs_reg_lock = self.register_manager.lockReg(rhs_reg);
+                defer if (rhs_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
                 const dest_reg = if (maybe_inst) |inst| blk: {
                     const bin_op = self.air.instructions.items(.data)[inst].bin_op;
@@ -1393,12 +1393,12 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     };
                     const dest = try self.binOp(base_tag, null, lhs, rhs, lhs_ty, rhs_ty);
                     const dest_reg = dest.register;
-                    const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                    defer self.register_manager.unfreezeReg(dest_reg_lock);
+                    const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                    defer self.register_manager.unlockReg(dest_reg_lock);
 
                     const truncated_reg = try self.register_manager.allocReg(null);
-                    const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                    defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                    const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                    defer self.register_manager.unlockReg(truncated_reg_lock);
 
                     // sbfx/ubfx truncated, dest, #0, #bits
                     try self.truncRegister(dest_reg, truncated_reg, int_info.signedness, int_info.bits);
@@ -1494,12 +1494,12 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
 
                     const dest = try self.binOpRegister(base_tag, null, lhs, rhs, lhs_ty, rhs_ty);
                     const dest_reg = dest.register;
-                    const dest_reg_lock = self.register_manager.freezeRegAssumeUnused(dest_reg);
-                    defer self.register_manager.unfreezeReg(dest_reg_lock);
+                    const dest_reg_lock = self.register_manager.lockRegAssumeUnused(dest_reg);
+                    defer self.register_manager.unlockReg(dest_reg_lock);
 
                     const truncated_reg = try self.register_manager.allocReg(null);
-                    const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                    defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                    const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                    defer self.register_manager.unlockReg(truncated_reg_lock);
 
                     // sbfx/ubfx truncated, dest, #0, #bits
                     try self.truncRegister(dest_reg, truncated_reg, int_info.signedness, int_info.bits);
@@ -1528,30 +1528,30 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     const rhs_is_register = rhs == .register;
 
                     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-                        self.register_manager.freezeReg(lhs.register)
+                        self.register_manager.lockReg(lhs.register)
                     else
                         null;
-                    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const lhs_reg = if (lhs_is_register)
                         lhs.register
                     else
                         try self.register_manager.allocReg(null);
-                    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-                    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+                    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const rhs_reg = if (rhs_is_register)
                         rhs.register
                     else
                         try self.register_manager.allocReg(null);
-                    const new_rhs_lock = self.register_manager.freezeReg(rhs_reg);
-                    defer if (new_rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    const new_rhs_lock = self.register_manager.lockReg(rhs_reg);
+                    defer if (new_rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     const dest_regs = try self.register_manager.allocRegs(2, .{ null, null });
                     var dest_regs_locks: [2]RegisterLock = undefined;
-                    self.register_manager.freezeRegsAssumeUnused(2, dest_regs, &dest_regs_locks);
+                    self.register_manager.lockRegsAssumeUnused(2, dest_regs, &dest_regs_locks);
                     defer for (dest_regs_locks) |reg| {
-                        self.register_manager.unfreezeReg(reg);
+                        self.register_manager.unlockReg(reg);
                     };
                     const rdlo = dest_regs[0];
                     const rdhi = dest_regs[1];
@@ -1560,8 +1560,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     if (!rhs_is_register) try self.genSetReg(rhs_ty, rhs_reg, rhs);
 
                     const truncated_reg = try self.register_manager.allocReg(null);
-                    const truncated_reg_lock = self.register_manager.freezeRegAssumeUnused(truncated_reg);
-                    defer self.register_manager.unfreezeReg(truncated_reg_lock);
+                    const truncated_reg_lock = self.register_manager.lockRegAssumeUnused(truncated_reg);
+                    defer self.register_manager.unlockReg(truncated_reg_lock);
 
                     _ = try self.addInst(.{
                         .tag = base_tag,
@@ -1654,10 +1654,10 @@ fn airShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     const stack_offset = try self.allocMem(inst, tuple_size, tuple_align);
 
                     const lhs_lock: ?RegisterLock = if (lhs == .register)
-                        self.register_manager.freezeRegAssumeUnused(lhs.register)
+                        self.register_manager.lockRegAssumeUnused(lhs.register)
                     else
                         null;
-                    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                     try self.spillCompareFlagsIfOccupied();
                     self.compare_flags_inst = null;
@@ -1948,10 +1948,10 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
         const slice_ptr_field_type = slice_ty.slicePtrFieldType(&buf);
 
         const index_lock: ?RegisterLock = if (index_is_register)
-            self.register_manager.freezeRegAssumeUnused(index_mcv.register)
+            self.register_manager.lockRegAssumeUnused(index_mcv.register)
         else
             null;
-        defer if (index_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (index_lock) |reg| self.register_manager.unlockReg(reg);
 
         const base_mcv = slicePtr(slice_mcv);
 
@@ -1961,20 +1961,20 @@ fn airSliceElemVal(self: *Self, inst: Air.Inst.Index) !void {
                     .register => |r| r,
                     else => try self.copyToTmpRegister(slice_ptr_field_type, base_mcv),
                 };
-                const base_reg_lock = self.register_manager.freezeRegAssumeUnused(base_reg);
-                defer self.register_manager.unfreezeReg(base_reg_lock);
+                const base_reg_lock = self.register_manager.lockRegAssumeUnused(base_reg);
+                defer self.register_manager.unlockReg(base_reg_lock);
 
                 const dst_reg = try self.register_manager.allocReg(inst);
                 const dst_mcv = MCValue{ .register = dst_reg };
-                const dst_reg_lock = self.register_manager.freezeRegAssumeUnused(dst_reg);
-                defer self.register_manager.unfreezeReg(dst_reg_lock);
+                const dst_reg_lock = self.register_manager.lockRegAssumeUnused(dst_reg);
+                defer self.register_manager.unlockReg(dst_reg_lock);
 
                 const index_reg: Register = switch (index_mcv) {
                     .register => |reg| reg,
                     else => try self.copyToTmpRegister(Type.usize, index_mcv),
                 };
-                const index_reg_lock = self.register_manager.freezeRegAssumeUnused(index_reg);
-                defer self.register_manager.unfreezeReg(index_reg_lock);
+                const index_reg_lock = self.register_manager.lockRegAssumeUnused(index_reg);
+                defer self.register_manager.unlockReg(index_reg_lock);
 
                 const tag: Mir.Inst.Tag = switch (elem_size) {
                     1 => .ldrb,
@@ -2160,8 +2160,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
         .immediate => |imm| try self.setRegOrMem(elem_ty, dst_mcv, .{ .memory = imm }),
         .ptr_stack_offset => |off| try self.setRegOrMem(elem_ty, dst_mcv, .{ .stack_offset = off }),
         .register => |reg| {
-            const reg_lock = self.register_manager.freezeReg(reg);
-            defer if (reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+            const reg_lock = self.register_manager.lockReg(reg);
+            defer if (reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
             switch (dst_mcv) {
                 .dead => unreachable,
@@ -2173,8 +2173,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
                 .stack_offset => |off| {
                     if (elem_size <= 4) {
                         const tmp_reg = try self.register_manager.allocReg(null);
-                        const tmp_reg_lock = self.register_manager.freezeRegAssumeUnused(tmp_reg);
-                        defer self.register_manager.unfreezeReg(tmp_reg_lock);
+                        const tmp_reg_lock = self.register_manager.lockRegAssumeUnused(tmp_reg);
+                        defer self.register_manager.unlockReg(tmp_reg_lock);
 
                         try self.load(.{ .register = tmp_reg }, ptr, ptr_ty);
                         try self.genSetStack(elem_ty, off, MCValue{ .register = tmp_reg });
@@ -2182,9 +2182,9 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
                         // TODO optimize the register allocation
                         const regs = try self.register_manager.allocRegs(4, .{ null, null, null, null });
                         var regs_locks: [4]RegisterLock = undefined;
-                        self.register_manager.freezeRegsAssumeUnused(4, regs, &regs_locks);
+                        self.register_manager.lockRegsAssumeUnused(4, regs, &regs_locks);
                         defer for (regs_locks) |reg_locked| {
-                            self.register_manager.unfreezeReg(reg_locked);
+                            self.register_manager.unlockReg(reg_locked);
                         };
 
                         const src_reg = reg;
@@ -2211,8 +2211,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
         .stack_argument_offset,
         => {
             const reg = try self.register_manager.allocReg(null);
-            const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-            defer self.register_manager.unfreezeReg(reg_lock);
+            const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+            defer self.register_manager.unlockReg(reg_lock);
 
             try self.genSetReg(ptr_ty, reg, ptr);
             try self.load(dst_mcv, .{ .register = reg }, ptr_ty);
@@ -2266,8 +2266,8 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
             try self.genSetStack(value_ty, off, value);
         },
         .register => |addr_reg| {
-            const addr_reg_lock = self.register_manager.freezeReg(addr_reg);
-            defer if (addr_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+            const addr_reg_lock = self.register_manager.lockReg(addr_reg);
+            defer if (addr_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
             switch (value) {
                 .dead => unreachable,
@@ -2278,17 +2278,17 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
                 else => {
                     if (elem_size <= 4) {
                         const tmp_reg = try self.register_manager.allocReg(null);
-                        const tmp_reg_lock = self.register_manager.freezeRegAssumeUnused(tmp_reg);
-                        defer self.register_manager.unfreezeReg(tmp_reg_lock);
+                        const tmp_reg_lock = self.register_manager.lockRegAssumeUnused(tmp_reg);
+                        defer self.register_manager.unlockReg(tmp_reg_lock);
 
                         try self.genSetReg(value_ty, tmp_reg, value);
                         try self.store(ptr, .{ .register = tmp_reg }, ptr_ty, value_ty);
                     } else {
                         const regs = try self.register_manager.allocRegs(4, .{ null, null, null, null });
                         var regs_locks: [4]RegisterLock = undefined;
-                        self.register_manager.freezeRegsAssumeUnused(4, regs, &regs_locks);
+                        self.register_manager.lockRegsAssumeUnused(4, regs, &regs_locks);
                         defer for (regs_locks) |reg| {
-                            self.register_manager.unfreezeReg(reg);
+                            self.register_manager.unlockReg(reg);
                         };
 
                         const src_reg = regs[0];
@@ -2373,12 +2373,12 @@ fn structFieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, inde
                 const offset_reg = try self.copyToTmpRegister(ptr_ty, .{
                     .immediate = struct_field_offset,
                 });
-                const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-                defer self.register_manager.unfreezeReg(offset_reg_lock);
+                const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+                defer self.register_manager.unlockReg(offset_reg_lock);
 
                 const addr_reg = try self.copyToTmpRegister(ptr_ty, mcv);
-                const addr_reg_lock = self.register_manager.freezeRegAssumeUnused(addr_reg);
-                defer self.register_manager.unfreezeReg(addr_reg_lock);
+                const addr_reg_lock = self.register_manager.lockRegAssumeUnused(addr_reg);
+                defer self.register_manager.unlockReg(addr_reg_lock);
 
                 const dest = try self.binOp(
                     .add,
@@ -2495,10 +2495,10 @@ fn binOpRegister(
     const rhs_is_register = rhs == .register;
 
     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-        self.register_manager.freezeReg(lhs.register)
+        self.register_manager.lockReg(lhs.register)
     else
         null;
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
 
@@ -2514,8 +2514,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs_reg = if (rhs_is_register) rhs.register else blk: {
         const track_inst: ?Air.Inst.Index = if (maybe_inst) |inst| inst: {
@@ -2529,8 +2529,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_rhs_lock = self.register_manager.freezeReg(rhs_reg);
-    defer if (new_rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_rhs_lock = self.register_manager.lockReg(rhs_reg);
+    defer if (new_rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dest_reg = switch (mir_tag) {
         .cmp => .r0, // cmp has no destination regardless
@@ -2614,10 +2614,10 @@ fn binOpImmediate(
     const lhs_is_register = lhs == .register;
 
     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-        self.register_manager.freezeReg(lhs.register)
+        self.register_manager.lockReg(lhs.register)
     else
         null;
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
 
@@ -2635,8 +2635,8 @@ fn binOpImmediate(
 
         break :blk reg;
     };
-    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dest_reg = switch (mir_tag) {
         .cmp => .r0, // cmp has no destination reg
src/arch/riscv64/CodeGen.zig
@@ -939,10 +939,10 @@ fn binOpRegister(
     const rhs_is_register = rhs == .register;
 
     const lhs_lock: ?RegisterLock = if (lhs_is_register)
-        self.register_manager.freezeReg(lhs.register)
+        self.register_manager.lockReg(lhs.register)
     else
         null;
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
 
@@ -958,8 +958,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_lhs_lock = self.register_manager.freezeReg(lhs_reg);
-    defer if (new_lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_lhs_lock = self.register_manager.lockReg(lhs_reg);
+    defer if (new_lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs_reg = if (rhs_is_register) rhs.register else blk: {
         const track_inst: ?Air.Inst.Index = if (maybe_inst) |inst| inst: {
@@ -973,8 +973,8 @@ fn binOpRegister(
 
         break :blk reg;
     };
-    const new_rhs_lock = self.register_manager.freezeReg(rhs_reg);
-    defer if (new_rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const new_rhs_lock = self.register_manager.lockReg(rhs_reg);
+    defer if (new_rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dest_reg = if (maybe_inst) |inst| blk: {
         const bin_op = self.air.instructions.items(.data)[inst].bin_op;
@@ -1452,8 +1452,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
         .stack_offset,
         => {
             const reg = try self.register_manager.allocReg(null);
-            const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-            defer self.register_manager.unfreezeReg(reg_lock);
+            const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+            defer self.register_manager.unlockReg(reg_lock);
 
             try self.genSetReg(ptr_ty, reg, ptr);
             try self.load(dst_mcv, .{ .register = reg }, ptr_ty);
src/arch/x86_64/CodeGen.zig
@@ -795,7 +795,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
             // zig fmt: on
         }
 
-        assert(!self.register_manager.frozenRegsExist());
+        assert(!self.register_manager.lockedRegsExist());
 
         if (std.debug.runtime_safety) {
             if (self.air_bookkeeping < old_air_bookkeeping + 1) {
@@ -1028,10 +1028,10 @@ fn airIntCast(self: *Self, inst: Air.Inst.Index) !void {
         }
 
         const operand_lock: ?RegisterLock = switch (operand) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
         const reg = try self.register_manager.allocReg(inst);
         try self.genSetReg(dest_ty, reg, .{ .immediate = 0 });
@@ -1059,10 +1059,10 @@ fn airTrunc(self: *Self, inst: Air.Inst.Index) !void {
     }
 
     const operand_lock: ?RegisterLock = switch (operand) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
     const reg: Register = blk: {
         if (operand.isRegister()) {
@@ -1147,21 +1147,21 @@ fn airMin(self: *Self, inst: Air.Inst.Index) !void {
         // TODO audit register allocation
         const lhs = try self.resolveInst(bin_op.lhs);
         const lhs_lock: ?RegisterLock = switch (lhs) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
         const lhs_reg = try self.copyToTmpRegister(ty, lhs);
-        const lhs_reg_lock = self.register_manager.freezeRegAssumeUnused(lhs_reg);
-        defer self.register_manager.unfreezeReg(lhs_reg_lock);
+        const lhs_reg_lock = self.register_manager.lockRegAssumeUnused(lhs_reg);
+        defer self.register_manager.unlockReg(lhs_reg_lock);
 
         const rhs_mcv = try self.limitImmediateType(bin_op.rhs, i32);
         const rhs_lock: ?RegisterLock = switch (rhs_mcv) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
         try self.genBinMathOpMir(.cmp, ty, .{ .register = lhs_reg }, rhs_mcv);
 
@@ -1197,10 +1197,10 @@ fn genPtrBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_r
     const offset_ty = self.air.typeOf(op_rhs);
 
     const offset_lock: ?RegisterLock = switch (offset) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (offset_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (offset_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dst_mcv = blk: {
         if (self.reuseOperand(inst, op_lhs, 0, ptr)) {
@@ -1210,10 +1210,10 @@ fn genPtrBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_r
     };
 
     const dst_mcv_lock: ?RegisterLock = switch (dst_mcv) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (dst_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dst_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const offset_mcv = blk: {
         if (self.reuseOperand(inst, op_rhs, 1, offset)) {
@@ -1223,10 +1223,10 @@ fn genPtrBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_r
     };
 
     const offset_mcv_lock: ?RegisterLock = switch (offset_mcv) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (offset_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (offset_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     try self.genIntMulComplexOpMir(offset_ty, offset_mcv, .{ .immediate = elem_size });
 
@@ -1312,17 +1312,17 @@ fn genSubOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs: Air
 
     const lhs = try self.resolveInst(op_lhs);
     const lhs_lock: ?RegisterLock = switch (lhs) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs = try self.resolveInst(op_rhs);
     const rhs_lock: ?RegisterLock = switch (rhs) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dst_mcv = blk: {
         if (self.reuseOperand(inst, op_lhs, 0, lhs) and lhs.isRegister()) {
@@ -1331,20 +1331,20 @@ fn genSubOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs: Air
         break :blk try self.copyToRegisterWithInstTracking(inst, dst_ty, lhs);
     };
     const dst_mcv_lock: ?RegisterLock = switch (dst_mcv) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (dst_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dst_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs_mcv = blk: {
         if (rhs.isMemory() or rhs.isRegister()) break :blk rhs;
         break :blk MCValue{ .register = try self.copyToTmpRegister(dst_ty, rhs) };
     };
     const rhs_mcv_lock: ?RegisterLock = switch (rhs_mcv) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (rhs_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (rhs_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     try self.genBinMathOpMir(.sub, dst_ty, dst_mcv, rhs_mcv);
 
@@ -1382,9 +1382,9 @@ fn airMul(self: *Self, inst: Air.Inst.Index) !void {
         try self.register_manager.getReg(.rax, inst);
         try self.register_manager.getReg(.rdx, null);
         var reg_locks: [2]RegisterLock = undefined;
-        self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+        self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
         defer for (reg_locks) |reg| {
-            self.register_manager.unfreezeReg(reg);
+            self.register_manager.unlockReg(reg);
         };
 
         const lhs = try self.resolveInst(bin_op.lhs);
@@ -1496,9 +1496,9 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                     try self.register_manager.getReg(.rax, inst);
                     try self.register_manager.getReg(.rdx, null);
                     var reg_locks: [2]RegisterLock = undefined;
-                    self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+                    self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
                     defer for (reg_locks) |reg| {
-                        self.register_manager.unfreezeReg(reg);
+                        self.register_manager.unlockReg(reg);
                     };
 
                     const lhs = try self.resolveInst(bin_op.lhs);
@@ -1526,27 +1526,27 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                             const rhs = try self.resolveInst(bin_op.rhs);
 
                             const rhs_lock: ?RegisterLock = switch (rhs) {
-                                .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+                                .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
                                 else => null,
                             };
-                            defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                            defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                             const dst_reg: Register = blk: {
                                 if (lhs.isRegister()) break :blk lhs.register;
                                 break :blk try self.copyToTmpRegister(ty, lhs);
                             };
-                            const dst_reg_lock = self.register_manager.freezeRegAssumeUnused(dst_reg);
-                            defer self.register_manager.unfreezeReg(dst_reg_lock);
+                            const dst_reg_lock = self.register_manager.lockRegAssumeUnused(dst_reg);
+                            defer self.register_manager.unlockReg(dst_reg_lock);
 
                             const rhs_mcv = blk: {
                                 if (rhs.isRegister() or rhs.isMemory()) break :blk rhs;
                                 break :blk MCValue{ .register = try self.copyToTmpRegister(ty, rhs) };
                             };
                             const rhs_mcv_lock: ?RegisterLock = switch (rhs_mcv) {
-                                .register => |reg| self.register_manager.freezeReg(reg),
+                                .register => |reg| self.register_manager.lockReg(reg),
                                 else => null,
                             };
-                            defer if (rhs_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+                            defer if (rhs_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
                             try self.genIntMulComplexOpMir(Type.isize, .{ .register = dst_reg }, rhs_mcv);
 
@@ -1557,9 +1557,9 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                             try self.register_manager.getReg(.rax, null);
                             try self.register_manager.getReg(.rdx, null);
                             var reg_locks: [2]RegisterLock = undefined;
-                            self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+                            self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
                             defer for (reg_locks) |reg| {
-                                self.register_manager.unfreezeReg(reg);
+                                self.register_manager.unlockReg(reg);
                             };
 
                             const lhs = try self.resolveInst(bin_op.lhs);
@@ -1571,8 +1571,8 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
                         },
                     }
                 };
-                const dst_reg_lock = self.register_manager.freezeRegAssumeUnused(dst_reg);
-                defer self.register_manager.unfreezeReg(dst_reg_lock);
+                const dst_reg_lock = self.register_manager.lockRegAssumeUnused(dst_reg);
+                defer self.register_manager.unlockReg(dst_reg_lock);
 
                 const tuple_ty = self.air.typeOfIndex(inst);
                 const tuple_size = @intCast(u32, tuple_ty.abiSize(self.target.*));
@@ -1587,9 +1587,9 @@ fn airMulWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
 
                 const temp_regs = try self.register_manager.allocRegs(3, .{ null, null, null });
                 var temp_regs_locks: [3]RegisterLock = undefined;
-                self.register_manager.freezeRegsAssumeUnused(3, temp_regs, &temp_regs_locks);
+                self.register_manager.lockRegsAssumeUnused(3, temp_regs, &temp_regs_locks);
                 defer for (temp_regs_locks) |reg| {
-                    self.register_manager.unfreezeReg(reg);
+                    self.register_manager.unlockReg(reg);
                 };
 
                 const overflow_reg = temp_regs[0];
@@ -1738,15 +1738,15 @@ fn genInlineIntDivFloor(self: *Self, ty: Type, lhs: MCValue, rhs: MCValue) !MCVa
         .register => |reg| reg,
         else => try self.copyToTmpRegister(ty, lhs),
     };
-    const dividend_lock = self.register_manager.freezeReg(dividend);
-    defer if (dividend_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const dividend_lock = self.register_manager.lockReg(dividend);
+    defer if (dividend_lock) |reg| self.register_manager.unlockReg(reg);
 
     const divisor = switch (rhs) {
         .register => |reg| reg,
         else => try self.copyToTmpRegister(ty, rhs),
     };
-    const divisor_lock = self.register_manager.freezeReg(divisor);
-    defer if (divisor_lock) |reg| self.register_manager.unfreezeReg(reg);
+    const divisor_lock = self.register_manager.lockReg(divisor);
+    defer if (divisor_lock) |reg| self.register_manager.unlockReg(reg);
 
     try self.genIntMulDivOpMir(switch (signedness) {
         .signed => .idiv,
@@ -1816,17 +1816,17 @@ fn airDiv(self: *Self, inst: Air.Inst.Index) !void {
         try self.register_manager.getReg(.rax, track_rax);
         try self.register_manager.getReg(.rdx, null);
         var reg_locks: [2]RegisterLock = undefined;
-        self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+        self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
         defer for (reg_locks) |reg| {
-            self.register_manager.unfreezeReg(reg);
+            self.register_manager.unlockReg(reg);
         };
 
         const lhs = try self.resolveInst(bin_op.lhs);
         const lhs_lock: ?RegisterLock = switch (lhs) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
         const rhs = blk: {
             const rhs = try self.resolveInst(bin_op.rhs);
@@ -1834,10 +1834,10 @@ fn airDiv(self: *Self, inst: Air.Inst.Index) !void {
                 switch (tag) {
                     .div_floor => {
                         const rhs_lock: ?RegisterLock = switch (rhs) {
-                            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+                            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
                             else => null,
                         };
-                        defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+                        defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
                         break :blk try self.copyToRegisterWithInstTracking(inst, ty, rhs);
                     },
@@ -1847,10 +1847,10 @@ fn airDiv(self: *Self, inst: Air.Inst.Index) !void {
             break :blk rhs;
         };
         const rhs_lock: ?RegisterLock = switch (rhs) {
-            .register => |reg| self.register_manager.freezeReg(reg),
+            .register => |reg| self.register_manager.lockReg(reg),
             else => null,
         };
-        defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
         if (signedness == .unsigned) {
             try self.genIntMulDivOpMir(.div, ty, signedness, lhs, rhs);
@@ -1885,9 +1885,9 @@ fn airRem(self: *Self, inst: Air.Inst.Index) !void {
         try self.register_manager.getReg(.rax, null);
         try self.register_manager.getReg(.rdx, inst);
         var reg_locks: [2]RegisterLock = undefined;
-        self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+        self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
         defer for (reg_locks) |reg| {
-            self.register_manager.unfreezeReg(reg);
+            self.register_manager.unlockReg(reg);
         };
 
         const lhs = try self.resolveInst(bin_op.lhs);
@@ -1916,9 +1916,9 @@ fn airMod(self: *Self, inst: Air.Inst.Index) !void {
         try self.register_manager.getReg(.rax, null);
         try self.register_manager.getReg(.rdx, if (signedness == .unsigned) inst else null);
         var reg_locks: [2]RegisterLock = undefined;
-        self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
+        self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rdx }, &reg_locks);
         defer for (reg_locks) |reg| {
-            self.register_manager.unfreezeReg(reg);
+            self.register_manager.unlockReg(reg);
         };
 
         const lhs = try self.resolveInst(bin_op.lhs);
@@ -2009,15 +2009,15 @@ fn airShl(self: *Self, inst: Air.Inst.Index) !void {
         try self.register_manager.getReg(.rcx, null);
         try self.genSetReg(shift_ty, .rcx, shift);
     }
-    const rcx_lock = self.register_manager.freezeRegAssumeUnused(.rcx);
-    defer self.register_manager.unfreezeReg(rcx_lock);
+    const rcx_lock = self.register_manager.lockRegAssumeUnused(.rcx);
+    defer self.register_manager.unlockReg(rcx_lock);
 
     const value = try self.resolveInst(bin_op.lhs);
     const value_lock: ?RegisterLock = switch (value) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (value_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (value_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dst_mcv = try self.copyToRegisterWithInstTracking(inst, ty, value);
     _ = try self.addInst(.{
@@ -2114,10 +2114,10 @@ fn airUnwrapErrErr(self: *Self, inst: Air.Inst.Index) !void {
     const payload_ty = err_union_ty.errorUnionPayload();
     const operand = try self.resolveInst(ty_op.operand);
     const operand_lock: ?RegisterLock = switch (operand) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
     const result: MCValue = result: {
         if (!payload_ty.hasRuntimeBits()) break :result operand;
@@ -2147,10 +2147,10 @@ fn airUnwrapErrPayload(self: *Self, inst: Air.Inst.Index) !void {
 
         const operand = try self.resolveInst(ty_op.operand);
         const operand_lock: ?RegisterLock = switch (operand) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
         const abi_align = err_union_ty.abiAlignment(self.target.*);
         const err_ty = err_union_ty.errorUnionSet();
@@ -2219,10 +2219,10 @@ fn airWrapOptional(self: *Self, inst: Air.Inst.Index) !void {
         const optional_ty = self.air.typeOfIndex(inst);
         const operand = try self.resolveInst(ty_op.operand);
         const operand_lock: ?RegisterLock = switch (operand) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
         if (optional_ty.isPtrLikeOptional()) {
             // TODO should we check if we can reuse the operand?
@@ -2356,10 +2356,10 @@ fn genSliceElemPtr(self: *Self, lhs: Air.Inst.Ref, rhs: Air.Inst.Ref) !MCValue {
     const slice_ty = self.air.typeOf(lhs);
     const slice_mcv = try self.resolveInst(lhs);
     const slice_mcv_lock: ?RegisterLock = switch (slice_mcv) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (slice_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (slice_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const elem_ty = slice_ty.childType();
     const elem_size = elem_ty.abiSize(self.target.*);
@@ -2369,14 +2369,14 @@ fn genSliceElemPtr(self: *Self, lhs: Air.Inst.Ref, rhs: Air.Inst.Ref) !MCValue {
     const index_ty = self.air.typeOf(rhs);
     const index_mcv = try self.resolveInst(rhs);
     const index_mcv_lock: ?RegisterLock = switch (index_mcv) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (index_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (index_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const offset_reg = try self.elemOffset(index_ty, index_mcv, elem_size);
-    const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-    defer self.register_manager.unfreezeReg(offset_reg_lock);
+    const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+    defer self.register_manager.unlockReg(offset_reg_lock);
 
     const addr_reg = try self.register_manager.allocReg(null);
     switch (slice_mcv) {
@@ -2433,10 +2433,10 @@ fn airArrayElemVal(self: *Self, inst: Air.Inst.Index) !void {
         const array_ty = self.air.typeOf(bin_op.lhs);
         const array = try self.resolveInst(bin_op.lhs);
         const array_lock: ?RegisterLock = switch (array) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (array_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (array_lock) |reg| self.register_manager.unlockReg(reg);
 
         const elem_ty = array_ty.childType();
         const elem_abi_size = elem_ty.abiSize(self.target.*);
@@ -2444,14 +2444,14 @@ fn airArrayElemVal(self: *Self, inst: Air.Inst.Index) !void {
         const index_ty = self.air.typeOf(bin_op.rhs);
         const index = try self.resolveInst(bin_op.rhs);
         const index_lock: ?RegisterLock = switch (index) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (index_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (index_lock) |reg| self.register_manager.unlockReg(reg);
 
         const offset_reg = try self.elemOffset(index_ty, index, elem_abi_size);
-        const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-        defer self.register_manager.unfreezeReg(offset_reg_lock);
+        const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+        defer self.register_manager.unlockReg(offset_reg_lock);
 
         const addr_reg = try self.register_manager.allocReg(null);
         switch (array) {
@@ -2512,24 +2512,24 @@ fn airPtrElemVal(self: *Self, inst: Air.Inst.Index) !void {
         const ptr_ty = self.air.typeOf(bin_op.lhs);
         const ptr = try self.resolveInst(bin_op.lhs);
         const ptr_lock: ?RegisterLock = switch (ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const elem_ty = ptr_ty.elemType2();
         const elem_abi_size = elem_ty.abiSize(self.target.*);
         const index_ty = self.air.typeOf(bin_op.rhs);
         const index = try self.resolveInst(bin_op.rhs);
         const index_lock: ?RegisterLock = switch (index) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (index_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (index_lock) |reg| self.register_manager.unlockReg(reg);
 
         const offset_reg = try self.elemOffset(index_ty, index, elem_abi_size);
-        const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-        defer self.register_manager.unfreezeReg(offset_reg_lock);
+        const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+        defer self.register_manager.unlockReg(offset_reg_lock);
 
         const dst_mcv = try self.copyToRegisterWithInstTracking(inst, ptr_ty, ptr);
         try self.genBinMathOpMir(.add, ptr_ty, dst_mcv, .{ .register = offset_reg });
@@ -2559,24 +2559,24 @@ fn airPtrElemPtr(self: *Self, inst: Air.Inst.Index) !void {
         const ptr_ty = self.air.typeOf(extra.lhs);
         const ptr = try self.resolveInst(extra.lhs);
         const ptr_lock: ?RegisterLock = switch (ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const elem_ty = ptr_ty.elemType2();
         const elem_abi_size = elem_ty.abiSize(self.target.*);
         const index_ty = self.air.typeOf(extra.rhs);
         const index = try self.resolveInst(extra.rhs);
         const index_lock: ?RegisterLock = switch (index) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (index_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (index_lock) |reg| self.register_manager.unlockReg(reg);
 
         const offset_reg = try self.elemOffset(index_ty, index, elem_abi_size);
-        const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-        defer self.register_manager.unfreezeReg(offset_reg_lock);
+        const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+        defer self.register_manager.unlockReg(offset_reg_lock);
 
         const dst_mcv = try self.copyToRegisterWithInstTracking(inst, ptr_ty, ptr);
         try self.genBinMathOpMir(.add, ptr_ty, dst_mcv, .{ .register = offset_reg });
@@ -2598,17 +2598,17 @@ fn airSetUnionTag(self: *Self, inst: Air.Inst.Index) !void {
 
     const ptr = try self.resolveInst(bin_op.lhs);
     const ptr_lock: ?RegisterLock = switch (ptr) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
     const tag = try self.resolveInst(bin_op.rhs);
     const tag_lock: ?RegisterLock = switch (tag) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (tag_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (tag_lock) |reg| self.register_manager.unlockReg(reg);
 
     const adjusted_ptr: MCValue = if (layout.payload_size > 0 and layout.tag_align < layout.payload_align) blk: {
         // TODO reusing the operand
@@ -2639,10 +2639,10 @@ fn airGetUnionTag(self: *Self, inst: Air.Inst.Index) !void {
     // TODO reusing the operand
     const operand = try self.resolveInst(ty_op.operand);
     const operand_lock: ?RegisterLock = switch (operand) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (operand_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (operand_lock) |reg| self.register_manager.unlockReg(reg);
 
     const tag_abi_size = tag_ty.abiSize(self.target.*);
     const dst_mcv: MCValue = blk: {
@@ -2789,8 +2789,8 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
             try self.setRegOrMem(elem_ty, dst_mcv, .{ .stack_offset = off });
         },
         .register => |reg| {
-            const reg_lock = self.register_manager.freezeReg(reg);
-            defer if (reg_lock) |locked_reg| self.register_manager.unfreezeReg(locked_reg);
+            const reg_lock = self.register_manager.lockReg(reg);
+            defer if (reg_lock) |locked_reg| self.register_manager.unlockReg(locked_reg);
 
             switch (dst_mcv) {
                 .dead => unreachable,
@@ -2915,8 +2915,8 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
             try self.genSetStack(value_ty, off, value, .{});
         },
         .register => |reg| {
-            const reg_lock = self.register_manager.freezeReg(reg);
-            defer if (reg_lock) |locked_reg| self.register_manager.unfreezeReg(locked_reg);
+            const reg_lock = self.register_manager.lockReg(reg);
+            defer if (reg_lock) |locked_reg| self.register_manager.unlockReg(locked_reg);
 
             switch (value) {
                 .none => unreachable,
@@ -3007,14 +3007,14 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
         .memory,
         => {
             const value_lock: ?RegisterLock = switch (value) {
-                .register => |reg| self.register_manager.freezeReg(reg),
+                .register => |reg| self.register_manager.lockReg(reg),
                 else => null,
             };
-            defer if (value_lock) |reg| self.register_manager.unfreezeReg(reg);
+            defer if (value_lock) |reg| self.register_manager.unlockReg(reg);
 
             const addr_reg = try self.register_manager.allocReg(null);
-            const addr_reg_lock = self.register_manager.freezeRegAssumeUnused(addr_reg);
-            defer self.register_manager.unfreezeReg(addr_reg_lock);
+            const addr_reg_lock = self.register_manager.lockRegAssumeUnused(addr_reg);
+            defer self.register_manager.unlockReg(addr_reg_lock);
 
             try self.loadMemPtrIntoRegister(addr_reg, ptr_ty, ptr);
 
@@ -3085,8 +3085,8 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
                 => {
                     if (abi_size <= 8) {
                         const tmp_reg = try self.register_manager.allocReg(null);
-                        const tmp_reg_lock = self.register_manager.freezeRegAssumeUnused(tmp_reg);
-                        defer self.register_manager.unfreezeReg(tmp_reg_lock);
+                        const tmp_reg_lock = self.register_manager.lockRegAssumeUnused(tmp_reg);
+                        defer self.register_manager.unlockReg(tmp_reg_lock);
 
                         try self.loadMemPtrIntoRegister(tmp_reg, value_ty, value);
 
@@ -3176,8 +3176,8 @@ fn structFieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, inde
                 const offset_reg = try self.copyToTmpRegister(ptr_ty, .{
                     .immediate = struct_field_offset,
                 });
-                const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-                defer self.register_manager.unfreezeReg(offset_reg_lock);
+                const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+                defer self.register_manager.unlockReg(offset_reg_lock);
 
                 const dst_mcv = try self.copyToRegisterWithInstTracking(inst, ptr_ty, mcv);
                 try self.genBinMathOpMir(.add, ptr_ty, dst_mcv, .{ .register = offset_reg });
@@ -3188,14 +3188,14 @@ fn structFieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, inde
                 break :result MCValue{ .ptr_stack_offset = ptr_stack_offset };
             },
             .register => |reg| {
-                const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-                defer self.register_manager.unfreezeReg(reg_lock);
+                const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+                defer self.register_manager.unlockReg(reg_lock);
 
                 const offset_reg = try self.copyToTmpRegister(ptr_ty, .{
                     .immediate = struct_field_offset,
                 });
-                const offset_reg_lock = self.register_manager.freezeRegAssumeUnused(offset_reg);
-                defer self.register_manager.unfreezeReg(offset_reg_lock);
+                const offset_reg_lock = self.register_manager.lockRegAssumeUnused(offset_reg);
+                defer self.register_manager.unlockReg(offset_reg_lock);
 
                 const can_reuse_operand = self.reuseOperand(inst, operand, 0, mcv);
                 const result_reg = blk: {
@@ -3207,8 +3207,8 @@ fn structFieldPtr(self: *Self, inst: Air.Inst.Index, operand: Air.Inst.Ref, inde
                         break :blk result_reg;
                     }
                 };
-                const result_reg_lock = self.register_manager.freezeReg(result_reg);
-                defer if (result_reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+                const result_reg_lock = self.register_manager.lockReg(result_reg);
+                defer if (result_reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
                 try self.genBinMathOpMir(.add, ptr_ty, .{ .register = result_reg }, .{ .register = offset_reg });
                 break :result MCValue{ .register = result_reg };
@@ -3236,8 +3236,8 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
                 break :result MCValue{ .stack_offset = stack_offset };
             },
             .register => |reg| {
-                const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-                defer self.register_manager.unfreezeReg(reg_lock);
+                const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+                defer self.register_manager.unlockReg(reg_lock);
 
                 const dst_mcv = blk: {
                     if (self.reuseOperand(inst, operand, 0, mcv)) {
@@ -3250,10 +3250,10 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
                     }
                 };
                 const dst_mcv_lock: ?RegisterLock = switch (dst_mcv) {
-                    .register => |reg| self.register_manager.freezeReg(reg),
+                    .register => |reg| self.register_manager.lockReg(reg),
                     else => null,
                 };
-                defer if (dst_mcv_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+                defer if (dst_mcv_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
                 // Shift by struct_field_offset.
                 const shift = @intCast(u8, struct_field_offset * @sizeOf(usize));
@@ -3295,8 +3295,8 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
                     },
                     1 => {
                         // Get overflow bit.
-                        const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-                        defer self.register_manager.unfreezeReg(reg_lock);
+                        const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+                        defer self.register_manager.unlockReg(reg_lock);
 
                         const dst_reg = try self.register_manager.allocReg(inst);
                         const flags: u2 = switch (mcv) {
@@ -3339,17 +3339,17 @@ fn genBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs:
 
     const lhs = try self.resolveInst(op_lhs);
     const lhs_lock: ?RegisterLock = switch (lhs) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     const rhs = try self.resolveInst(op_rhs);
     const rhs_lock: ?RegisterLock = switch (rhs) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (rhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (rhs_lock) |reg| self.register_manager.unlockReg(reg);
 
     var flipped: bool = false;
     const dst_mcv = blk: {
@@ -3363,10 +3363,10 @@ fn genBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs:
         break :blk try self.copyToRegisterWithInstTracking(inst, dst_ty, lhs);
     };
     const dst_mcv_lock: ?RegisterLock = switch (dst_mcv) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (dst_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dst_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const src_mcv = blk: {
         const mcv = if (flipped) lhs else rhs;
@@ -3374,10 +3374,10 @@ fn genBinMathOp(self: *Self, inst: Air.Inst.Index, op_lhs: Air.Inst.Ref, op_rhs:
         break :blk MCValue{ .register = try self.copyToTmpRegister(dst_ty, mcv) };
     };
     const src_mcv_lock: ?RegisterLock = switch (src_mcv) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (src_mcv_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (src_mcv_lock) |reg| self.register_manager.unlockReg(reg);
 
     const tag = self.air.instructions.items(.tag)[inst];
     switch (tag) {
@@ -3408,8 +3408,8 @@ fn genBinMathOpMir(self: *Self, mir_tag: Mir.Inst.Tag, dst_ty: Type, dst_mcv: MC
                 .register_overflow_unsigned => unreachable,
                 .register_overflow_signed => unreachable,
                 .ptr_stack_offset => {
-                    const dst_reg_lock = self.register_manager.freezeReg(dst_reg);
-                    defer if (dst_reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+                    const dst_reg_lock = self.register_manager.lockReg(dst_reg);
+                    defer if (dst_reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
                     const reg = try self.copyToTmpRegister(dst_ty, src_mcv);
                     return self.genBinMathOpMir(mir_tag, dst_ty, dst_mcv, .{ .register = reg });
@@ -3440,8 +3440,8 @@ fn genBinMathOpMir(self: *Self, mir_tag: Mir.Inst.Tag, dst_ty: Type, dst_mcv: MC
                 .compare_flags_unsigned,
                 => {
                     assert(abi_size <= 8);
-                    const dst_reg_lock = self.register_manager.freezeReg(dst_reg);
-                    defer if (dst_reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+                    const dst_reg_lock = self.register_manager.lockReg(dst_reg);
+                    defer if (dst_reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
                     const reg = try self.copyToTmpRegister(dst_ty, src_mcv);
                     return self.genBinMathOpMir(mir_tag, dst_ty, dst_mcv, .{ .register = reg });
@@ -3791,13 +3791,13 @@ fn airCall(self: *Self, inst: Air.Inst.Index, modifier: std.builtin.CallOptions.
 
         try self.register_manager.getReg(.rdi, null);
         try self.genSetReg(Type.usize, .rdi, .{ .ptr_stack_offset = stack_offset });
-        const rdi_lock = self.register_manager.freezeRegAssumeUnused(.rdi);
+        const rdi_lock = self.register_manager.lockRegAssumeUnused(.rdi);
 
         info.return_value.stack_offset = stack_offset;
 
         break :blk rdi_lock;
     } else null;
-    defer if (rdi_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (rdi_lock) |reg| self.register_manager.unlockReg(reg);
 
     for (args) |arg, arg_i| {
         const mc_arg = info.args[arg_i];
@@ -4017,8 +4017,8 @@ fn airRet(self: *Self, inst: Air.Inst.Index) !void {
     switch (self.ret_mcv) {
         .stack_offset => {
             const reg = try self.copyToTmpRegister(Type.usize, self.ret_mcv);
-            const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-            defer self.register_manager.unfreezeReg(reg_lock);
+            const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+            defer self.register_manager.unlockReg(reg_lock);
 
             try self.genSetStack(ret_ty, 0, operand, .{
                 .source_stack_base = .rbp,
@@ -4051,8 +4051,8 @@ fn airRetLoad(self: *Self, inst: Air.Inst.Index) !void {
     switch (self.ret_mcv) {
         .stack_offset => {
             const reg = try self.copyToTmpRegister(Type.usize, self.ret_mcv);
-            const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-            defer self.register_manager.unfreezeReg(reg_lock);
+            const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+            defer self.register_manager.unlockReg(reg_lock);
 
             try self.genInlineMemcpy(.{ .stack_offset = 0 }, ptr, .{ .immediate = elem_ty.abiSize(self.target.*) }, .{
                 .source_stack_base = .rbp,
@@ -4104,14 +4104,14 @@ fn airCmp(self: *Self, inst: Air.Inst.Index, op: math.CompareOperator) !void {
         // TODO look into reusing the operand
         const lhs = try self.resolveInst(bin_op.lhs);
         const lhs_lock: ?RegisterLock = switch (lhs) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (lhs_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (lhs_lock) |reg| self.register_manager.unlockReg(reg);
 
         const dst_reg = try self.copyToTmpRegister(ty, lhs);
-        const dst_reg_lock = self.register_manager.freezeRegAssumeUnused(dst_reg);
-        defer self.register_manager.unfreezeReg(dst_reg_lock);
+        const dst_reg_lock = self.register_manager.lockRegAssumeUnused(dst_reg);
+        defer self.register_manager.unlockReg(dst_reg_lock);
 
         const dst_mcv = MCValue{ .register = dst_reg };
 
@@ -4576,10 +4576,10 @@ fn airIsNullPtr(self: *Self, inst: Air.Inst.Index) !void {
         const operand_ptr = try self.resolveInst(un_op);
 
         const operand_ptr_lock: ?RegisterLock = switch (operand_ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
@@ -4612,10 +4612,10 @@ fn airIsNonNullPtr(self: *Self, inst: Air.Inst.Index) !void {
         const operand_ptr = try self.resolveInst(un_op);
 
         const operand_ptr_lock: ?RegisterLock = switch (operand_ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
@@ -4648,10 +4648,10 @@ fn airIsErrPtr(self: *Self, inst: Air.Inst.Index) !void {
         const operand_ptr = try self.resolveInst(un_op);
 
         const operand_ptr_lock: ?RegisterLock = switch (operand_ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
@@ -4684,10 +4684,10 @@ fn airIsNonErrPtr(self: *Self, inst: Air.Inst.Index) !void {
         const operand_ptr = try self.resolveInst(un_op);
 
         const operand_ptr_lock: ?RegisterLock = switch (operand_ptr) {
-            .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+            .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
             else => null,
         };
-        defer if (operand_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+        defer if (operand_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
@@ -4756,8 +4756,8 @@ fn genCondSwitchMir(self: *Self, ty: Type, condition: MCValue, case: MCValue) !u
         .register => |cond_reg| {
             try self.spillCompareFlagsIfOccupied();
 
-            const cond_reg_lock = self.register_manager.freezeReg(cond_reg);
-            defer if (cond_reg_lock) |reg| self.register_manager.unfreezeReg(reg);
+            const cond_reg_lock = self.register_manager.lockReg(cond_reg);
+            defer if (cond_reg_lock) |reg| self.register_manager.unlockReg(reg);
 
             switch (case) {
                 .none => unreachable,
@@ -4816,8 +4816,8 @@ fn genCondSwitchMir(self: *Self, ty: Type, condition: MCValue, case: MCValue) !u
 
             if (abi_size <= 8) {
                 const reg = try self.copyToTmpRegister(ty, condition);
-                const reg_lock = self.register_manager.freezeRegAssumeUnused(reg);
-                defer self.register_manager.unfreezeReg(reg_lock);
+                const reg_lock = self.register_manager.lockRegAssumeUnused(reg);
+                defer self.register_manager.unlockReg(reg_lock);
                 return self.genCondSwitchMir(ty, .{ .register = reg }, case);
             }
 
@@ -5304,8 +5304,8 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: i32, mcv: MCValue, opts: Inl
         .register_overflow_unsigned,
         .register_overflow_signed,
         => |reg| {
-            const reg_lock = self.register_manager.freezeReg(reg);
-            defer if (reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+            const reg_lock = self.register_manager.lockReg(reg);
+            defer if (reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
             const wrapped_ty = ty.structFieldType(0);
             try self.genSetStack(wrapped_ty, stack_offset, .{ .register = reg }, .{});
@@ -5406,8 +5406,8 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: i32, mcv: MCValue, opts: Inl
 
             const base_reg = opts.dest_stack_base orelse .rbp;
             if (!math.isPowerOfTwo(abi_size)) {
-                const reg_lock = self.register_manager.freezeReg(reg);
-                defer if (reg_lock) |reg_locked| self.register_manager.unfreezeReg(reg_locked);
+                const reg_lock = self.register_manager.lockReg(reg);
+                defer if (reg_lock) |reg_locked| self.register_manager.unlockReg(reg_locked);
 
                 const tmp_reg = try self.copyToTmpRegister(ty, mcv);
 
@@ -5500,22 +5500,22 @@ fn genInlineMemcpy(
     try self.register_manager.getReg(.rcx, null);
 
     var reg_locks: [2]RegisterLock = undefined;
-    self.register_manager.freezeRegsAssumeUnused(2, .{ .rax, .rcx }, &reg_locks);
+    self.register_manager.lockRegsAssumeUnused(2, .{ .rax, .rcx }, &reg_locks);
     defer for (reg_locks) |reg| {
-        self.register_manager.unfreezeReg(reg);
+        self.register_manager.unlockReg(reg);
     };
 
     const ssbase_lock: ?RegisterLock = if (opts.source_stack_base) |reg|
-        self.register_manager.freezeReg(reg)
+        self.register_manager.lockReg(reg)
     else
         null;
-    defer if (ssbase_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (ssbase_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dsbase_lock: ?RegisterLock = if (opts.dest_stack_base) |reg|
-        self.register_manager.freezeReg(reg)
+        self.register_manager.lockReg(reg)
     else
         null;
-    defer if (dsbase_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dsbase_lock) |reg| self.register_manager.unlockReg(reg);
 
     const dst_addr_reg = try self.register_manager.allocReg(null);
     switch (dst_ptr) {
@@ -5549,8 +5549,8 @@ fn genInlineMemcpy(
             return self.fail("TODO implement memcpy for setting stack when dest is {}", .{dst_ptr});
         },
     }
-    const dst_addr_reg_lock = self.register_manager.freezeRegAssumeUnused(dst_addr_reg);
-    defer self.register_manager.unfreezeReg(dst_addr_reg_lock);
+    const dst_addr_reg_lock = self.register_manager.lockRegAssumeUnused(dst_addr_reg);
+    defer self.register_manager.unlockReg(dst_addr_reg_lock);
 
     const src_addr_reg = try self.register_manager.allocReg(null);
     switch (src_ptr) {
@@ -5584,8 +5584,8 @@ fn genInlineMemcpy(
             return self.fail("TODO implement memcpy for setting stack when src is {}", .{src_ptr});
         },
     }
-    const src_addr_reg_lock = self.register_manager.freezeRegAssumeUnused(src_addr_reg);
-    defer self.register_manager.unfreezeReg(src_addr_reg_lock);
+    const src_addr_reg_lock = self.register_manager.lockRegAssumeUnused(src_addr_reg);
+    defer self.register_manager.unlockReg(src_addr_reg_lock);
 
     const regs = try self.register_manager.allocRegs(2, .{ null, null });
     const count_reg = regs[0].to64();
@@ -5695,8 +5695,8 @@ fn genInlineMemset(
     opts: InlineMemcpyOpts,
 ) InnerError!void {
     try self.register_manager.getReg(.rax, null);
-    const rax_lock = self.register_manager.freezeRegAssumeUnused(.rax);
-    defer self.register_manager.unfreezeReg(rax_lock);
+    const rax_lock = self.register_manager.lockRegAssumeUnused(.rax);
+    defer self.register_manager.unlockReg(rax_lock);
 
     const addr_reg = try self.register_manager.allocReg(null);
     switch (dst_ptr) {
@@ -5730,8 +5730,8 @@ fn genInlineMemset(
             return self.fail("TODO implement memcpy for setting stack when dest is {}", .{dst_ptr});
         },
     }
-    const addr_reg_lock = self.register_manager.freezeRegAssumeUnused(addr_reg);
-    defer self.register_manager.unfreezeReg(addr_reg_lock);
+    const addr_reg_lock = self.register_manager.lockRegAssumeUnused(addr_reg);
+    defer self.register_manager.unlockReg(addr_reg_lock);
 
     try self.genSetReg(Type.usize, .rax, len);
     try self.genBinMathOpMir(.sub, Type.usize, .{ .register = .rax }, .{ .immediate = 1 });
@@ -6171,24 +6171,24 @@ fn airMemset(self: *Self, inst: Air.Inst.Index) !void {
 
     const dst_ptr = try self.resolveInst(pl_op.operand);
     const dst_ptr_lock: ?RegisterLock = switch (dst_ptr) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (dst_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dst_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
     const src_val = try self.resolveInst(extra.lhs);
     const src_val_lock: ?RegisterLock = switch (src_val) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (src_val_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (src_val_lock) |reg| self.register_manager.unlockReg(reg);
 
     const len = try self.resolveInst(extra.rhs);
     const len_lock: ?RegisterLock = switch (len) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (len_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (len_lock) |reg| self.register_manager.unlockReg(reg);
 
     try self.genInlineMemset(dst_ptr, src_val, len, .{});
 
@@ -6201,25 +6201,25 @@ fn airMemcpy(self: *Self, inst: Air.Inst.Index) !void {
 
     const dst_ptr = try self.resolveInst(pl_op.operand);
     const dst_ptr_lock: ?RegisterLock = switch (dst_ptr) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (dst_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (dst_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
     const src_ty = self.air.typeOf(extra.lhs);
     const src_ptr = try self.resolveInst(extra.lhs);
     const src_ptr_lock: ?RegisterLock = switch (src_ptr) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (src_ptr_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (src_ptr_lock) |reg| self.register_manager.unlockReg(reg);
 
     const len = try self.resolveInst(extra.rhs);
     const len_lock: ?RegisterLock = switch (len) {
-        .register => |reg| self.register_manager.freezeRegAssumeUnused(reg),
+        .register => |reg| self.register_manager.lockRegAssumeUnused(reg),
         else => null,
     };
-    defer if (len_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (len_lock) |reg| self.register_manager.unlockReg(reg);
 
     // TODO Is this the only condition for pointer dereference for memcpy?
     const src: MCValue = blk: {
@@ -6242,10 +6242,10 @@ fn airMemcpy(self: *Self, inst: Air.Inst.Index) !void {
         }
     };
     const src_lock: ?RegisterLock = switch (src) {
-        .register => |reg| self.register_manager.freezeReg(reg),
+        .register => |reg| self.register_manager.lockReg(reg),
         else => null,
     };
-    defer if (src_lock) |reg| self.register_manager.unfreezeReg(reg);
+    defer if (src_lock) |reg| self.register_manager.unlockReg(reg);
 
     try self.genInlineMemcpy(dst_ptr, src, len, .{});
src/register_manager.zig
@@ -45,9 +45,8 @@ pub fn RegisterManager(
         /// Tracks all registers allocated in the course of this
         /// function
         allocated_registers: FreeRegInt = 0,
-        /// Tracks registers which are temporarily blocked from being
-        /// allocated
-        frozen_registers: FreeRegInt = 0,
+        /// Tracks registers which are locked from being allocated
+        locked_registers: FreeRegInt = 0,
 
         const Self = @This();
 
@@ -108,12 +107,12 @@ pub fn RegisterManager(
             return self.allocated_registers & mask != 0;
         }
 
-        /// Returns whether this register is frozen
+        /// Returns whether this register is locked
         ///
         /// Returns false when this register is not tracked
-        pub fn isRegFrozen(self: Self, reg: Register) bool {
+        pub fn isRegLocked(self: Self, reg: Register) bool {
             const mask = getRegisterMask(reg) orelse return false;
-            return self.frozen_registers & mask != 0;
+            return self.locked_registers & mask != 0;
         }
 
         pub const RegisterLock = struct {
@@ -121,56 +120,56 @@ pub fn RegisterManager(
         };
 
         /// Prevents the register from being allocated until they are
-        /// unfrozen again.
+        /// unlocked again.
         /// Returns `RegisterLock` if the register was not already
-        /// frozen, or `null` otherwise.
-        /// Only the owner of the `RegisterLock` can unfreeze the
+        /// locked, or `null` otherwise.
+        /// Only the owner of the `RegisterLock` can unlock the
         /// register later.
-        pub fn freezeReg(self: *Self, reg: Register) ?RegisterLock {
-            log.debug("freezing {}", .{reg});
-            if (self.isRegFrozen(reg)) {
+        pub fn lockReg(self: *Self, reg: Register) ?RegisterLock {
+            log.debug("locking {}", .{reg});
+            if (self.isRegLocked(reg)) {
                 log.debug("  register already locked", .{});
                 return null;
             }
             const mask = getRegisterMask(reg) orelse return null;
-            self.frozen_registers |= mask;
+            self.locked_registers |= mask;
             return RegisterLock{ .register = reg };
         }
 
-        /// Like `freezeReg` but asserts the register was unused always
+        /// Like `lockReg` but asserts the register was unused always
         /// returning a valid lock.
-        pub fn freezeRegAssumeUnused(self: *Self, reg: Register) RegisterLock {
-            log.debug("freezing asserting free {}", .{reg});
-            assert(!self.isRegFrozen(reg));
+        pub fn lockRegAssumeUnused(self: *Self, reg: Register) RegisterLock {
+            log.debug("locking asserting free {}", .{reg});
+            assert(!self.isRegLocked(reg));
             const mask = getRegisterMask(reg) orelse unreachable;
-            self.frozen_registers |= mask;
+            self.locked_registers |= mask;
             return RegisterLock{ .register = reg };
         }
 
-        /// Like `freezeRegAssumeUnused` but locks multiple registers.
-        pub fn freezeRegsAssumeUnused(
+        /// Like `lockRegAssumeUnused` but locks multiple registers.
+        pub fn lockRegsAssumeUnused(
             self: *Self,
             comptime count: comptime_int,
             regs: [count]Register,
             buf: *[count]RegisterLock,
         ) void {
             for (&regs) |reg, i| {
-                buf[i] = self.freezeRegAssumeUnused(reg);
+                buf[i] = self.lockRegAssumeUnused(reg);
             }
         }
 
-        /// Unfreezes the register allowing its re-allocation and re-use.
-        /// Requires `RegisterLock` to unfreeze a register.
-        /// Call `freezeReg` to obtain the lock first.
-        pub fn unfreezeReg(self: *Self, lock: RegisterLock) void {
-            log.debug("unfreezing {}", .{lock.register});
+        /// Unlocks the register allowing its re-allocation and re-use.
+        /// Requires `RegisterLock` to unlock a register.
+        /// Call `lockReg` to obtain the lock first.
+        pub fn unlockReg(self: *Self, lock: RegisterLock) void {
+            log.debug("unlocking {}", .{lock.register});
             const mask = getRegisterMask(lock.register) orelse return;
-            self.frozen_registers &= ~mask;
+            self.locked_registers &= ~mask;
         }
 
-        /// Returns true when at least one register is frozen
-        pub fn frozenRegsExist(self: Self) bool {
-            return self.frozen_registers != 0;
+        /// Returns true when at least one register is locked
+        pub fn lockedRegsExist(self: Self) bool {
+            return self.locked_registers != 0;
         }
 
         /// Allocates a specified number of registers, optionally
@@ -183,15 +182,15 @@ pub fn RegisterManager(
         ) ?[count]Register {
             comptime assert(count > 0 and count <= tracked_registers.len);
 
-            const free_and_not_frozen_registers = self.free_registers & ~self.frozen_registers;
-            const free_and_not_frozen_registers_count = @popCount(FreeRegInt, free_and_not_frozen_registers);
-            if (free_and_not_frozen_registers_count < count) return null;
+            const free_and_not_locked_registers = self.free_registers & ~self.locked_registers;
+            const free_and_not_locked_registers_count = @popCount(FreeRegInt, free_and_not_locked_registers);
+            if (free_and_not_locked_registers_count < count) return null;
 
             var regs: [count]Register = undefined;
             var i: usize = 0;
             for (tracked_registers) |reg| {
                 if (i >= count) break;
-                if (self.isRegFrozen(reg)) continue;
+                if (self.isRegLocked(reg)) continue;
                 if (!self.isRegFree(reg)) continue;
 
                 regs[i] = reg;
@@ -229,8 +228,8 @@ pub fn RegisterManager(
             insts: [count]?Air.Inst.Index,
         ) AllocateRegistersError![count]Register {
             comptime assert(count > 0 and count <= tracked_registers.len);
-            const frozen_registers_count = @popCount(FreeRegInt, self.frozen_registers);
-            if (count > tracked_registers.len - frozen_registers_count) return error.OutOfRegisters;
+            const locked_registers_count = @popCount(FreeRegInt, self.locked_registers);
+            if (count > tracked_registers.len - locked_registers_count) return error.OutOfRegisters;
 
             const result = self.tryAllocRegs(count, insts) orelse blk: {
                 // We'll take over the first count registers. Spill
@@ -240,7 +239,7 @@ pub fn RegisterManager(
                 var i: usize = 0;
                 for (tracked_registers) |reg| {
                     if (i >= count) break;
-                    if (self.isRegFrozen(reg)) continue;
+                    if (self.isRegLocked(reg)) continue;
 
                     regs[i] = reg;
                     self.markRegAllocated(reg);
@@ -451,15 +450,15 @@ test "allocReg: spilling" {
     try expectEqual(@as(?MockRegister1, .r3), try function.register_manager.allocReg(mock_instruction));
     try expectEqualSlices(MockRegister1, &[_]MockRegister1{.r2}, function.spilled.items);
 
-    // Frozen registers
+    // Locked registers
     function.register_manager.freeReg(.r3);
     {
-        const lock = function.register_manager.freezeReg(.r2);
-        defer if (lock) |reg| function.register_manager.unfreezeReg(reg);
+        const lock = function.register_manager.lockReg(.r2);
+        defer if (lock) |reg| function.register_manager.unlockReg(reg);
 
         try expectEqual(@as(?MockRegister1, .r3), try function.register_manager.allocReg(mock_instruction));
     }
-    try expect(!function.register_manager.frozenRegsExist());
+    try expect(!function.register_manager.lockedRegsExist());
 }
 
 test "tryAllocRegs" {
@@ -477,17 +476,17 @@ test "tryAllocRegs" {
     try expect(function.register_manager.isRegAllocated(.r2));
     try expect(!function.register_manager.isRegAllocated(.r3));
 
-    // Frozen registers
+    // Locked registers
     function.register_manager.freeReg(.r0);
     function.register_manager.freeReg(.r2);
     function.register_manager.freeReg(.r3);
     {
-        const lock = function.register_manager.freezeReg(.r1);
-        defer if (lock) |reg| function.register_manager.unfreezeReg(reg);
+        const lock = function.register_manager.lockReg(.r1);
+        defer if (lock) |reg| function.register_manager.unlockReg(reg);
 
         try expectEqual([_]MockRegister2{ .r0, .r2, .r3 }, function.register_manager.tryAllocRegs(3, .{ null, null, null }).?);
     }
-    try expect(!function.register_manager.frozenRegsExist());
+    try expect(!function.register_manager.lockedRegsExist());
 
     try expect(function.register_manager.isRegAllocated(.r0));
     try expect(function.register_manager.isRegAllocated(.r1));
@@ -510,19 +509,19 @@ test "allocRegs: normal usage" {
 
         // The result register is known and fixed at this point, we
         // don't want to accidentally allocate lhs or rhs to the
-        // result register, this is why we freeze it.
+        // result register, this is why we lock it.
         //
-        // Using defer unfreeze right after freeze is a good idea in
-        // most cases as you probably are using the frozen registers
+        // Using defer unlock right after lock is a good idea in
+        // most cases as you probably are using the locked registers
         // in the remainder of this scope and don't need to use it
         // after the end of this scope. However, in some situations,
-        // it may make sense to manually unfreeze registers before the
+        // it may make sense to manually unlock registers before the
         // end of the scope when you are certain that they don't
         // contain any valuable data anymore and can be reused. For an
         // example of that, see `selectively reducing register
         // pressure`.
-        const lock = function.register_manager.freezeReg(result_reg);
-        defer if (lock) |reg| function.register_manager.unfreezeReg(reg);
+        const lock = function.register_manager.lockReg(result_reg);
+        defer if (lock) |reg| function.register_manager.unlockReg(reg);
 
         const regs = try function.register_manager.allocRegs(2, .{ null, null });
         try function.genAdd(result_reg, regs[0], regs[1]);
@@ -542,14 +541,14 @@ test "allocRegs: selectively reducing register pressure" {
     {
         const result_reg: MockRegister2 = .r1;
 
-        const lock = function.register_manager.freezeReg(result_reg);
+        const lock = function.register_manager.lockReg(result_reg);
 
-        // Here, we don't defer unfreeze because we manually unfreeze
+        // Here, we don't defer unlock because we manually unlock
         // after genAdd
         const regs = try function.register_manager.allocRegs(2, .{ null, null });
 
         try function.genAdd(result_reg, regs[0], regs[1]);
-        function.register_manager.unfreezeReg(lock.?);
+        function.register_manager.unlockReg(lock.?);
 
         const extra_summand_reg = try function.register_manager.allocReg(null);
         try function.genAdd(result_reg, result_reg, extra_summand_reg);