207 lines
8.1 KiB
Zig
207 lines
8.1 KiB
Zig
const std = @import("std");
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const link = @import("../link.zig");
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const Module = @import("../Module.zig");
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const Inst = @import("../ir.zig").Inst;
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const Value = @import("../value.zig").Value;
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const Type = @import("../type.zig").Type;
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const C = link.File.C;
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const Decl = Module.Decl;
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const mem = std.mem;
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/// Maps a name from Zig source to C. This will always give the same output for
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/// any given input.
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fn map(allocator: *std.mem.Allocator, name: []const u8) ![]const u8 {
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return allocator.dupe(u8, name);
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}
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fn renderType(file: *C, writer: std.ArrayList(u8).Writer, T: Type, src: usize) !void {
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if (T.tag() == .usize) {
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file.need_stddef = true;
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try writer.writeAll("size_t");
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} else {
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switch (T.zigTypeTag()) {
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.NoReturn => {
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file.need_noreturn = true;
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try writer.writeAll("noreturn void");
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},
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.Void => try writer.writeAll("void"),
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.Int => {
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if (T.tag() == .u8) {
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file.need_stdint = true;
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try writer.writeAll("uint8_t");
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} else {
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return file.fail(src, "TODO implement int types", .{});
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}
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},
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else => |e| return file.fail(src, "TODO implement type {}", .{e}),
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}
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}
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}
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fn renderFunctionSignature(file: *C, writer: std.ArrayList(u8).Writer, decl: *Decl) !void {
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const tv = decl.typed_value.most_recent.typed_value;
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try renderType(file, writer, tv.ty.fnReturnType(), decl.src());
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const name = try map(file.allocator, mem.spanZ(decl.name));
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defer file.allocator.free(name);
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try writer.print(" {}(", .{name});
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if (tv.ty.fnParamLen() == 0)
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try writer.writeAll("void)")
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else
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return file.fail(decl.src(), "TODO implement parameters", .{});
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}
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pub fn generate(file: *C, decl: *Decl) !void {
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switch (decl.typed_value.most_recent.typed_value.ty.zigTypeTag()) {
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.Fn => try genFn(file, decl),
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.Array => try genArray(file, decl),
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else => |e| return file.fail(decl.src(), "TODO {}", .{e}),
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}
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}
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fn genArray(file: *C, decl: *Decl) !void {
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const tv = decl.typed_value.most_recent.typed_value;
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// TODO: prevent inline asm constants from being emitted
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const name = try map(file.allocator, mem.span(decl.name));
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defer file.allocator.free(name);
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if (tv.val.cast(Value.Payload.Bytes)) |payload|
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if (tv.ty.arraySentinel()) |sentinel|
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if (sentinel.toUnsignedInt() == 0)
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try file.constants.writer().print("const char *const {} = \"{}\";\n", .{ name, payload.data })
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else
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return file.fail(decl.src(), "TODO byte arrays with non-zero sentinels", .{})
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else
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return file.fail(decl.src(), "TODO byte arrays without sentinels", .{})
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else
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return file.fail(decl.src(), "TODO non-byte arrays", .{});
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}
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fn genFn(file: *C, decl: *Decl) !void {
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const writer = file.main.writer();
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const tv = decl.typed_value.most_recent.typed_value;
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try renderFunctionSignature(file, writer, decl);
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try writer.writeAll(" {");
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const func: *Module.Fn = tv.val.cast(Value.Payload.Function).?.func;
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const instructions = func.analysis.success.instructions;
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if (instructions.len > 0) {
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for (instructions) |inst| {
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try writer.writeAll("\n\t");
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switch (inst.tag) {
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.assembly => try genAsm(file, inst.cast(Inst.Assembly).?, decl),
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.call => try genCall(file, inst.cast(Inst.Call).?, decl),
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.ret => try genRet(file, inst.cast(Inst.Ret).?, decl, tv.ty.fnReturnType()),
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.retvoid => try file.main.writer().print("return;", .{}),
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else => |e| return file.fail(decl.src(), "TODO implement C codegen for {}", .{e}),
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}
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}
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try writer.writeAll("\n");
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}
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try writer.writeAll("}\n\n");
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}
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fn genRet(file: *C, inst: *Inst.Ret, decl: *Decl, expected_return_type: Type) !void {
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const writer = file.main.writer();
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const ret_value = inst.args.operand;
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const value = ret_value.value().?;
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if (expected_return_type.eql(ret_value.ty))
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return file.fail(decl.src(), "TODO return {}", .{expected_return_type})
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else if (expected_return_type.isInt() and ret_value.ty.tag() == .comptime_int)
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if (value.intFitsInType(expected_return_type, file.options.target))
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if (expected_return_type.intInfo(file.options.target).bits <= 64)
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try writer.print("return {};", .{value.toUnsignedInt()})
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else
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return file.fail(decl.src(), "TODO return ints > 64 bits", .{})
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else
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return file.fail(decl.src(), "comptime int {} does not fit in {}", .{ value.toUnsignedInt(), expected_return_type })
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else
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return file.fail(decl.src(), "return type mismatch: expected {}, found {}", .{ expected_return_type, ret_value.ty });
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}
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fn genCall(file: *C, inst: *Inst.Call, decl: *Decl) !void {
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const writer = file.main.writer();
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const header = file.header.writer();
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if (inst.args.func.cast(Inst.Constant)) |func_inst| {
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if (func_inst.val.cast(Value.Payload.Function)) |func_val| {
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const target = func_val.func.owner_decl;
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const target_ty = target.typed_value.most_recent.typed_value.ty;
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const ret_ty = target_ty.fnReturnType().tag();
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if (target_ty.fnReturnType().hasCodeGenBits() and inst.base.isUnused()) {
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try writer.print("(void)", .{});
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}
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const tname = mem.spanZ(target.name);
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if (file.called.get(tname) == null) {
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try file.called.put(tname, void{});
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try renderFunctionSignature(file, header, target);
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try header.writeAll(";\n");
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}
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try writer.print("{}();", .{tname});
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} else {
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return file.fail(decl.src(), "TODO non-function call target?", .{});
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}
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if (inst.args.args.len != 0) {
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return file.fail(decl.src(), "TODO function arguments", .{});
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}
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} else {
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return file.fail(decl.src(), "TODO non-constant call inst?", .{});
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}
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}
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fn genAsm(file: *C, inst: *Inst.Assembly, decl: *Decl) !void {
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const as = inst.args;
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const writer = file.main.writer();
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for (as.inputs) |i, index| {
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if (i[0] == '{' and i[i.len - 1] == '}') {
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const reg = i[1 .. i.len - 1];
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const arg = as.args[index];
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if (arg.cast(Inst.Constant)) |c| {
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if (c.val.tag() == .int_u64) {
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try writer.writeAll("register ");
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try renderType(file, writer, arg.ty, decl.src());
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try writer.print(" {}_constant __asm__(\"{}\") = {};\n\t", .{ reg, reg, c.val.toUnsignedInt() });
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} else {
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return file.fail(decl.src(), "TODO inline asm {} args", .{c.val.tag()});
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}
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} else {
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return file.fail(decl.src(), "TODO non-constant inline asm args", .{});
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}
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} else {
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return file.fail(decl.src(), "TODO non-explicit inline asm regs", .{});
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}
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}
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try writer.print("__asm {} (\"{}\"", .{ if (as.is_volatile) @as([]const u8, "volatile") else "", as.asm_source });
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if (as.output) |o| {
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return file.fail(decl.src(), "TODO inline asm output", .{});
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}
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if (as.inputs.len > 0) {
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if (as.output == null) {
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try writer.writeAll(" :");
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}
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try writer.writeAll(": ");
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for (as.inputs) |i, index| {
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if (i[0] == '{' and i[i.len - 1] == '}') {
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const reg = i[1 .. i.len - 1];
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const arg = as.args[index];
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if (index > 0) {
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try writer.writeAll(", ");
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}
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if (arg.cast(Inst.Constant)) |c| {
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try writer.print("\"\"({}_constant)", .{reg});
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} else {
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// This is blocked by the earlier test
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unreachable;
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}
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} else {
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// This is blocked by the earlier test
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unreachable;
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}
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}
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}
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try writer.writeAll(");");
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}
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