1value: u64 = 0,
2out_n_sect: u8 = 0,
3symbols: std.array_hash_map.Auto(MachO.Ref, void) = .empty,
4output_symtab_ctx: MachO.SymtabCtx = .{},
5
6pub fn deinit(thunk: *Thunk, allocator: Allocator) void {
7 thunk.symbols.deinit(allocator);
8}
9
10pub fn size(thunk: Thunk) usize {
11 return thunk.symbols.keys().len * trampoline_size;
12}
13
14pub fn getAddress(thunk: Thunk, macho_file: *MachO) u64 {
15 const header = macho_file.sections.items(.header)[thunk.out_n_sect];
16 return header.addr + thunk.value;
17}
18
19pub fn getTargetAddress(thunk: Thunk, ref: MachO.Ref, macho_file: *MachO) u64 {
20 return thunk.getAddress(macho_file) + thunk.symbols.getIndex(ref).? * trampoline_size;
21}
22
23pub fn write(thunk: Thunk, macho_file: *MachO, writer: anytype) !void {
24 const Instruction = aarch64.encoding.Instruction;
25 for (thunk.symbols.keys(), 0..) |ref, i| {
26 const sym = ref.getSymbol(macho_file).?;
27 const saddr = thunk.getAddress(macho_file) + i * trampoline_size;
28 const taddr = sym.getAddress(.{}, macho_file);
29 const pages = try aarch64.calcNumberOfPages(@intCast(saddr), @intCast(taddr));
30 try writer.writeInt(u32, @bitCast(Instruction.adrp(.x16, pages << 12)), .little);
31 try writer.writeInt(u32, @bitCast(
32 Instruction.add(.x16, .x16, .{ .immediate = @truncate(taddr) }),
33 ), .little);
34 try writer.writeInt(u32, @bitCast(Instruction.br(.x16)), .little);
35 }
36}
37
38pub fn calcSymtabSize(thunk: *Thunk, macho_file: *MachO) void {
39 thunk.output_symtab_ctx.nlocals = @as(u32, @intCast(thunk.symbols.keys().len));
40 for (thunk.symbols.keys()) |ref| {
41 const sym = ref.getSymbol(macho_file).?;
42 thunk.output_symtab_ctx.strsize += @as(u32, @intCast(sym.getName(macho_file).len + "__thunk".len + 1));
43 }
44}
45
46pub fn writeSymtab(thunk: Thunk, macho_file: *MachO, ctx: anytype) void {
47 var n_strx = thunk.output_symtab_ctx.stroff;
48 for (thunk.symbols.keys(), thunk.output_symtab_ctx.ilocal..) |ref, ilocal| {
49 const sym = ref.getSymbol(macho_file).?;
50 const name = sym.getName(macho_file);
51 const out_sym = &ctx.symtab.items[ilocal];
52 out_sym.n_strx = n_strx;
53 @memcpy(ctx.strtab.items[n_strx..][0..name.len], name);
54 n_strx += @intCast(name.len);
55 @memcpy(ctx.strtab.items[n_strx..][0.."__thunk".len], "__thunk");
56 n_strx += @intCast("__thunk".len);
57 ctx.strtab.items[n_strx] = 0;
58 n_strx += 1;
59 out_sym.n_type = .{ .bits = .{ .ext = false, .type = .sect, .pext = false, .is_stab = 0 } };
60 out_sym.n_sect = @intCast(thunk.out_n_sect + 1);
61 out_sym.n_value = @intCast(thunk.getTargetAddress(ref, macho_file));
62 out_sym.n_desc = @bitCast(@as(u16, 0));
63 }
64}
65
66pub fn fmt(thunk: Thunk, macho_file: *MachO) std.fmt.Alt(Format, Format.default) {
67 return .{ .data = .{
68 .thunk = thunk,
69 .macho_file = macho_file,
70 } };
71}
72
73const Format = struct {
74 thunk: Thunk,
75 macho_file: *MachO,
76
77 fn default(f: Format, w: *Writer) Writer.Error!void {
78 const thunk = f.thunk;
79 const macho_file = f.macho_file;
80 try w.print("@{x} : size({x})\n", .{ thunk.value, thunk.size() });
81 for (thunk.symbols.keys()) |ref| {
82 const sym = ref.getSymbol(macho_file).?;
83 try w.print(" {f} : {s} : @{x}\n", .{ ref, sym.getName(macho_file), sym.value });
84 }
85 }
86};
87
88const trampoline_size = 3 * @sizeOf(u32);
89
90pub const Index = u32;
91
92const aarch64 = @import("../aarch64.zig");
93const assert = std.debug.assert;
94const log = std.log.scoped(.link);
95const macho = std.macho;
96const math = std.math;
97const mem = std.mem;
98const std = @import("std");
99const trace = @import("../../tracy.zig").trace;
100const Writer = std.Io.Writer;
101
102const Allocator = mem.Allocator;
103const Atom = @import("Atom.zig");
104const MachO = @import("../MachO.zig");
105const Relocation = @import("Relocation.zig");
106const Symbol = @import("Symbol.zig");
107
108const Thunk = @This();