diff options
Diffstat (limited to 'src/codegen.zig')
| -rw-r--r-- | src/codegen.zig | 126 |
1 files changed, 92 insertions, 34 deletions
diff --git a/src/codegen.zig b/src/codegen.zig index 59b7040..b0bf5c5 100644 --- a/src/codegen.zig +++ b/src/codegen.zig @@ -436,6 +436,11 @@ const RegisterAllocator = struct { }; } + fn deinit(self: *RegisterAllocator) void { + self.allocated.deinit(); + self.available.deinit(); + } + fn get(self: *const RegisterAllocator, vreg: compile.VReg) Register { return self.allocated.get(vreg).?; } @@ -455,50 +460,103 @@ const RegisterAllocator = struct { } }; -pub fn create_elf(allocator: Allocator, block: compile.Block) ![]u8 { - var output_buffer: std.ArrayList(u8) = .init(allocator); - errdefer output_buffer.deinit(); - try output_buffer.appendNTimes(undefined, @sizeOf(elf.Elf64_Ehdr) + @sizeOf(elf.Elf64_Phdr)); +const Context = struct { + register_allocator: RegisterAllocator, + instructions: std.ArrayList(Instruction), - const output = output_buffer.writer(); - var register_allocator: RegisterAllocator = try .init(allocator); + // Current stuff that changes often, basically here to avoid prop drilling. + block: ?*const compile.Block = null, + current_instruction_index: ?usize = null, + + fn deinit(self: *Context) void { + self.register_allocator.deinit(); + self.instructions.deinit(); + } + + fn emit(self: *Context, inst: Instruction) !void { + try self.instructions.append(inst); + } + + fn maybeFreeSources(self: *Context, vregs: compile.Instr.Sources) !void { + for (vregs.slice()) |src| { + if (self.block.?.vreg_last_use.get(src) == self.current_instruction_index.?) { + self.register_allocator.free(src); + } + } + } + + fn genConstant(self: *Context, constant: compile.Instr.Constant) !void { + const reg = self.register_allocator.allocate(constant.dest) orelse return error.OutOfRegisters; + + if (constant.value <= std.math.maxInt(i12)) { + try self.emit(.addi(reg, .zero, @intCast(constant.value))); + } else if (constant.value <= std.math.maxInt(i32)) { + // If the higest bit in the immediate in addi is set, it will be sign extended. We negate that by adding one more to the immediate for lui. + try self.emit(.lui(reg, @intCast((constant.value >> 12) + if (constant.value & (1 << 11) != 0) @as(u64, 1) else 0))); + try self.emit(.addi(reg, reg, @bitCast(@as(u12, @truncate(constant.value))))); + } else { + unreachable; // TODO + } + } - for (0.., block.instrs) |i, instr| { + fn genBinOp(self: *Context, bin_op: compile.Instr.BinOp) !void { + const lhs = self.register_allocator.get(bin_op.lhs); + const rhs = self.register_allocator.get(bin_op.rhs); + try self.maybeFreeSources(bin_op.sources()); + const reg = self.register_allocator.allocate(bin_op.dest) orelse return error.OutOfRegisters; + switch (bin_op.op) { + .add => try self.emit(.add(reg, lhs, rhs)), + } + } + + fn codegenInstr(self: *Context, instr: compile.Instr) !void { switch (instr.type) { - .constant => |constant| { - const reg = register_allocator.allocate(constant.dest) orelse return error.OutOfRegisters; - - if (constant.value <= std.math.maxInt(i12)) { - try output.writeInt(u32, @bitCast(Instruction.addi(reg, .zero, @intCast(constant.value))), .little); - } else if (constant.value <= std.math.maxInt(i32)) { - // If the higest bit in the immediate in addi is set, it will be sign extended. We negate that by adding one more to the immediate for lui. - try output.writeInt(u32, @bitCast(Instruction.lui(reg, @intCast((constant.value >> 12) + if (constant.value & (1 << 11) != 0) @as(u64, 1) else 0))), .little); - try output.writeInt(u32, @bitCast(Instruction.addi(reg, reg, @bitCast(@as(u12, @truncate(constant.value))))), .little); - } else { - unreachable; // TODO - } - }, - .bin_op => |bin_op| { - const lhs = register_allocator.get(bin_op.lhs); - const rhs = register_allocator.get(bin_op.rhs); - for (instr.sources().slice()) |src| { - if (block.vreg_last_use.get(src) == i) { - register_allocator.free(src); + inline else => |ty| { + const func = comptime blk: { + const typeName = @typeName(@TypeOf(ty)); + var it = std.mem.splitBackwardsScalar(u8, typeName, '.'); + const base = it.first(); + if (!@hasDecl(Context, "gen" ++ base)) { + @compileError(std.fmt.comptimePrint( + "codegen.Context must have a member named 'gen{s}' " ++ + "since compile.Instr.Type has a variant named {s}", + .{ base, typeName }, + )); } - } - const reg = register_allocator.allocate(bin_op.dest) orelse return error.OutOfRegisters; - switch (bin_op.op) { - .add => try output.writeInt(u32, @bitCast(Instruction.add(reg, lhs, rhs)), .little), - } + break :blk @field(Context, "gen" ++ base); + }; + try func(self, ty); }, } } - for ([_]Instruction{ - .addi(.a0, register_allocator.get(block.instrs[block.instrs.len - 1].dest()), 0), + fn codegenBlock(self: *Context, block: compile.Block) !void { + self.block = █ + defer self.block = null; + for (block.instrs, 0..) |instr, i| { + self.current_instruction_index = i; + try self.codegenInstr(instr); + } + } +}; + +pub fn create_elf(allocator: Allocator, block: compile.Block) ![]u8 { + var ctx: Context = .{ .register_allocator = try .init(allocator), .instructions = .init(allocator) }; + defer ctx.deinit(); + + try ctx.codegenBlock(block); + + try ctx.instructions.appendSlice(&[_]Instruction{ + .addi(.a0, ctx.register_allocator.get(block.instrs[block.instrs.len - 1].dest()), 0), .addi(.a7, .zero, 93), .ecall(), - }) |instr| { + }); + + var output_buffer: std.ArrayList(u8) = .init(allocator); + errdefer output_buffer.deinit(); + try output_buffer.appendNTimes(undefined, @sizeOf(elf.Elf64_Ehdr) + @sizeOf(elf.Elf64_Phdr)); + const output = output_buffer.writer(); + for (ctx.instructions.items) |instr| { try output.writeInt(u32, @bitCast(instr), .little); } |