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| 1 | const Zld = @This(); |
| 2 | |
| 3 | const std = @import("std"); |
| 4 | const assert = std.debug.assert; |
| 5 | const dwarf = std.dwarf; |
| 6 | const leb = std.leb; |
| 7 | const mem = std.mem; |
| 8 | const meta = std.meta; |
| 9 | const fs = std.fs; |
| 10 | const macho = std.macho; |
| 11 | const math = std.math; |
| 12 | const log = std.log.scoped(.zld); |
| 13 | const aarch64 = @import("../../codegen/aarch64.zig"); |
| 14 | |
| 15 | const Allocator = mem.Allocator; |
| 16 | const CodeSignature = @import("CodeSignature.zig"); |
| 17 | const Archive = @import("Archive.zig"); |
| 18 | const Object = @import("Object.zig"); |
| 19 | const Trie = @import("Trie.zig"); |
| 20 | |
| 21 | usingnamespace @import("commands.zig"); |
| 22 | usingnamespace @import("bind.zig"); |
| 23 | |
| 24 | allocator: *Allocator, |
| 25 | |
| 26 | arch: ?std.Target.Cpu.Arch = null, |
| 27 | page_size: ?u16 = null, |
| 28 | file: ?fs.File = null, |
| 29 | out_path: ?[]const u8 = null, |
| 30 | |
| 31 | // TODO Eventually, we will want to keep track of the archives themselves to be able to exclude objects |
| 32 | // contained within from landing in the final artifact. For now however, since we don't optimise the binary |
| 33 | // at all, we just move all objects from the archives into the final artifact. |
| 34 | objects: std.ArrayListUnmanaged(Object) = .{}, |
| 35 | |
| 36 | load_commands: std.ArrayListUnmanaged(LoadCommand) = .{}, |
| 37 | |
| 38 | pagezero_segment_cmd_index: ?u16 = null, |
| 39 | text_segment_cmd_index: ?u16 = null, |
| 40 | data_const_segment_cmd_index: ?u16 = null, |
| 41 | data_segment_cmd_index: ?u16 = null, |
| 42 | linkedit_segment_cmd_index: ?u16 = null, |
| 43 | dyld_info_cmd_index: ?u16 = null, |
| 44 | symtab_cmd_index: ?u16 = null, |
| 45 | dysymtab_cmd_index: ?u16 = null, |
| 46 | dylinker_cmd_index: ?u16 = null, |
| 47 | libsystem_cmd_index: ?u16 = null, |
| 48 | data_in_code_cmd_index: ?u16 = null, |
| 49 | function_starts_cmd_index: ?u16 = null, |
| 50 | main_cmd_index: ?u16 = null, |
| 51 | version_min_cmd_index: ?u16 = null, |
| 52 | source_version_cmd_index: ?u16 = null, |
| 53 | uuid_cmd_index: ?u16 = null, |
| 54 | code_signature_cmd_index: ?u16 = null, |
| 55 | |
| 56 | // __TEXT segment sections |
| 57 | text_section_index: ?u16 = null, |
| 58 | stubs_section_index: ?u16 = null, |
| 59 | stub_helper_section_index: ?u16 = null, |
| 60 | text_const_section_index: ?u16 = null, |
| 61 | cstring_section_index: ?u16 = null, |
| 62 | |
| 63 | // __DATA segment sections |
| 64 | got_section_index: ?u16 = null, |
| 65 | tlv_section_index: ?u16 = null, |
| 66 | tlv_data_section_index: ?u16 = null, |
| 67 | tlv_bss_section_index: ?u16 = null, |
| 68 | la_symbol_ptr_section_index: ?u16 = null, |
| 69 | data_const_section_index: ?u16 = null, |
| 70 | data_section_index: ?u16 = null, |
| 71 | bss_section_index: ?u16 = null, |
| 72 | |
| 73 | locals: std.StringArrayHashMapUnmanaged(std.ArrayListUnmanaged(Symbol)) = .{}, |
| 74 | exports: std.StringArrayHashMapUnmanaged(macho.nlist_64) = .{}, |
| 75 | nonlazy_imports: std.StringArrayHashMapUnmanaged(Import) = .{}, |
| 76 | lazy_imports: std.StringArrayHashMapUnmanaged(Import) = .{}, |
| 77 | tlv_bootstrap: ?Import = null, |
| 78 | threadlocal_offsets: std.ArrayListUnmanaged(u64) = .{}, |
| 79 | local_rebases: std.ArrayListUnmanaged(Pointer) = .{}, |
| 80 | nonlazy_pointers: std.StringArrayHashMapUnmanaged(GotEntry) = .{}, |
| 81 | |
| 82 | strtab: std.ArrayListUnmanaged(u8) = .{}, |
| 83 | |
| 84 | stub_helper_stubs_start_off: ?u64 = null, |
| 85 | |
| 86 | mappings: std.AutoHashMapUnmanaged(MappingKey, SectionMapping) = .{}, |
| 87 | unhandled_sections: std.AutoHashMapUnmanaged(MappingKey, u0) = .{}, |
| 88 | |
| 89 | // TODO this will require scanning the relocations at least one to work out |
| 90 | // the exact amount of local GOT indirections. For the time being, set some |
| 91 | // default value. |
| 92 | const max_local_got_indirections: u16 = 1000; |
| 93 | |
| 94 | const GotEntry = struct { |
| 95 | index: u32, |
| 96 | target_addr: u64, |
| 97 | }; |
| 98 | |
| 99 | const MappingKey = struct { |
| 100 | object_id: u16, |
| 101 | source_sect_id: u16, |
| 102 | }; |
| 103 | |
| 104 | const SectionMapping = struct { |
| 105 | source_sect_id: u16, |
| 106 | target_seg_id: u16, |
| 107 | target_sect_id: u16, |
| 108 | offset: u32, |
| 109 | }; |
| 110 | |
| 111 | const Symbol = struct { |
| 112 | inner: macho.nlist_64, |
| 113 | tt: Type, |
| 114 | object_id: u16, |
| 115 | |
| 116 | const Type = enum { |
| 117 | Local, |
| 118 | WeakGlobal, |
| 119 | Global, |
| 120 | }; |
| 121 | }; |
| 122 | |
| 123 | const DebugInfo = struct { |
| 124 | inner: dwarf.DwarfInfo, |
| 125 | debug_info: []u8, |
| 126 | debug_abbrev: []u8, |
| 127 | debug_str: []u8, |
| 128 | debug_line: []u8, |
| 129 | debug_ranges: []u8, |
| 130 | |
| 131 | pub fn parseFromObject(allocator: *Allocator, object: Object) !?DebugInfo { |
| 132 | var debug_info = blk: { |
| 133 | const index = object.dwarf_debug_info_index orelse return null; |
| 134 | break :blk try object.readSection(allocator, index); |
| 135 | }; |
| 136 | var debug_abbrev = blk: { |
| 137 | const index = object.dwarf_debug_abbrev_index orelse return null; |
| 138 | break :blk try object.readSection(allocator, index); |
| 139 | }; |
| 140 | var debug_str = blk: { |
| 141 | const index = object.dwarf_debug_str_index orelse return null; |
| 142 | break :blk try object.readSection(allocator, index); |
| 143 | }; |
| 144 | var debug_line = blk: { |
| 145 | const index = object.dwarf_debug_line_index orelse return null; |
| 146 | break :blk try object.readSection(allocator, index); |
| 147 | }; |
| 148 | var debug_ranges = blk: { |
| 149 | if (object.dwarf_debug_ranges_index) |ind| { |
| 150 | break :blk try object.readSection(allocator, ind); |
| 151 | } |
| 152 | break :blk try allocator.alloc(u8, 0); |
| 153 | }; |
| 154 | |
| 155 | var inner: dwarf.DwarfInfo = .{ |
| 156 | .endian = .Little, |
| 157 | .debug_info = debug_info, |
| 158 | .debug_abbrev = debug_abbrev, |
| 159 | .debug_str = debug_str, |
| 160 | .debug_line = debug_line, |
| 161 | .debug_ranges = debug_ranges, |
| 162 | }; |
| 163 | try dwarf.openDwarfDebugInfo(&inner, allocator); |
| 164 | |
| 165 | return DebugInfo{ |
| 166 | .inner = inner, |
| 167 | .debug_info = debug_info, |
| 168 | .debug_abbrev = debug_abbrev, |
| 169 | .debug_str = debug_str, |
| 170 | .debug_line = debug_line, |
| 171 | .debug_ranges = debug_ranges, |
| 172 | }; |
| 173 | } |
| 174 | |
| 175 | pub fn deinit(self: *DebugInfo, allocator: *Allocator) void { |
| 176 | allocator.free(self.debug_info); |
| 177 | allocator.free(self.debug_abbrev); |
| 178 | allocator.free(self.debug_str); |
| 179 | allocator.free(self.debug_line); |
| 180 | allocator.free(self.debug_ranges); |
| 181 | self.inner.abbrev_table_list.deinit(); |
| 182 | self.inner.compile_unit_list.deinit(); |
| 183 | self.inner.func_list.deinit(); |
| 184 | } |
| 185 | }; |
| 186 | |
| 187 | pub const Import = struct { |
| 188 | /// MachO symbol table entry. |
| 189 | symbol: macho.nlist_64, |
| 190 | |
| 191 | /// Id of the dynamic library where the specified entries can be found. |
| 192 | dylib_ordinal: i64, |
| 193 | |
| 194 | /// Index of this import within the import list. |
| 195 | index: u32, |
| 196 | }; |
| 197 | |
| 198 | /// Default path to dyld |
| 199 | /// TODO instead of hardcoding it, we should probably look through some env vars and search paths |
| 200 | /// instead but this will do for now. |
| 201 | const DEFAULT_DYLD_PATH: [*:0]const u8 = "/usr/lib/dyld"; |
| 202 | |
| 203 | /// Default lib search path |
| 204 | /// TODO instead of hardcoding it, we should probably look through some env vars and search paths |
| 205 | /// instead but this will do for now. |
| 206 | const DEFAULT_LIB_SEARCH_PATH: []const u8 = "/usr/lib"; |
| 207 | |
| 208 | const LIB_SYSTEM_NAME: [*:0]const u8 = "System"; |
| 209 | /// TODO we should search for libSystem and fail if it doesn't exist, instead of hardcoding it |
| 210 | const LIB_SYSTEM_PATH: [*:0]const u8 = DEFAULT_LIB_SEARCH_PATH ++ "/libSystem.B.dylib"; |
| 211 | |
| 212 | pub fn init(allocator: *Allocator) Zld { |
| 213 | return .{ .allocator = allocator }; |
| 214 | } |
| 215 | |
| 216 | pub fn deinit(self: *Zld) void { |
| 217 | self.threadlocal_offsets.deinit(self.allocator); |
| 218 | self.strtab.deinit(self.allocator); |
| 219 | self.local_rebases.deinit(self.allocator); |
| 220 | for (self.lazy_imports.items()) |*entry| { |
| 221 | self.allocator.free(entry.key); |
| 222 | } |
| 223 | self.lazy_imports.deinit(self.allocator); |
| 224 | for (self.nonlazy_imports.items()) |*entry| { |
| 225 | self.allocator.free(entry.key); |
| 226 | } |
| 227 | self.nonlazy_imports.deinit(self.allocator); |
| 228 | for (self.nonlazy_pointers.items()) |*entry| { |
| 229 | self.allocator.free(entry.key); |
| 230 | } |
| 231 | self.nonlazy_pointers.deinit(self.allocator); |
| 232 | for (self.exports.items()) |*entry| { |
| 233 | self.allocator.free(entry.key); |
| 234 | } |
| 235 | self.exports.deinit(self.allocator); |
| 236 | for (self.locals.items()) |*entry| { |
| 237 | self.allocator.free(entry.key); |
| 238 | entry.value.deinit(self.allocator); |
| 239 | } |
| 240 | self.locals.deinit(self.allocator); |
| 241 | for (self.objects.items) |*object| { |
| 242 | object.deinit(); |
| 243 | } |
| 244 | self.objects.deinit(self.allocator); |
| 245 | for (self.load_commands.items) |*lc| { |
| 246 | lc.deinit(self.allocator); |
| 247 | } |
| 248 | self.load_commands.deinit(self.allocator); |
| 249 | self.mappings.deinit(self.allocator); |
| 250 | self.unhandled_sections.deinit(self.allocator); |
| 251 | if (self.file) |*f| f.close(); |
| 252 | } |
| 253 | |
| 254 | pub fn link(self: *Zld, files: []const []const u8, out_path: []const u8) !void { |
| 255 | if (files.len == 0) return error.NoInputFiles; |
| 256 | if (out_path.len == 0) return error.EmptyOutputPath; |
| 257 | |
| 258 | if (self.arch == null) { |
| 259 | // Try inferring the arch from the object files. |
| 260 | self.arch = blk: { |
| 261 | const file = try fs.cwd().openFile(files[0], .{}); |
| 262 | defer file.close(); |
| 263 | var reader = file.reader(); |
| 264 | const header = try reader.readStruct(macho.mach_header_64); |
| 265 | const arch: std.Target.Cpu.Arch = switch (header.cputype) { |
| 266 | macho.CPU_TYPE_X86_64 => .x86_64, |
| 267 | macho.CPU_TYPE_ARM64 => .aarch64, |
| 268 | else => |value| { |
| 269 | log.err("unsupported cpu architecture 0x{x}", .{value}); |
| 270 | return error.UnsupportedCpuArchitecture; |
| 271 | }, |
| 272 | }; |
| 273 | break :blk arch; |
| 274 | }; |
| 275 | } |
| 276 | |
| 277 | self.page_size = switch (self.arch.?) { |
| 278 | .aarch64 => 0x4000, |
| 279 | .x86_64 => 0x1000, |
| 280 | else => unreachable, |
| 281 | }; |
| 282 | self.out_path = out_path; |
| 283 | self.file = try fs.cwd().createFile(out_path, .{ |
| 284 | .truncate = true, |
| 285 | .read = true, |
| 286 | .mode = if (std.Target.current.os.tag == .windows) 0 else 0o777, |
| 287 | }); |
| 288 | |
| 289 | try self.populateMetadata(); |
| 290 | try self.parseInputFiles(files); |
| 291 | try self.sortSections(); |
| 292 | try self.resolveImports(); |
| 293 | try self.allocateTextSegment(); |
| 294 | try self.allocateDataConstSegment(); |
| 295 | try self.allocateDataSegment(); |
| 296 | self.allocateLinkeditSegment(); |
| 297 | try self.writeStubHelperCommon(); |
| 298 | try self.resolveSymbols(); |
| 299 | try self.doRelocs(); |
| 300 | try self.flush(); |
| 301 | } |
| 302 | |
| 303 | fn parseInputFiles(self: *Zld, files: []const []const u8) !void { |
| 304 | for (files) |file_name| { |
| 305 | const file = try fs.cwd().openFile(file_name, .{}); |
| 306 | |
| 307 | try_object: { |
| 308 | var object = Object.initFromFile(self.allocator, self.arch.?, file_name, file) catch |err| switch (err) { |
| 309 | error.NotObject => break :try_object, |
| 310 | else => |e| return e, |
| 311 | }; |
| 312 | const index = @intCast(u16, self.objects.items.len); |
| 313 | try self.objects.append(self.allocator, object); |
| 314 | try self.updateMetadata(index); |
| 315 | continue; |
| 316 | } |
| 317 | |
| 318 | try_archive: { |
| 319 | var archive = Archive.initFromFile(self.allocator, self.arch.?, file_name, file) catch |err| switch (err) { |
| 320 | error.NotArchive => break :try_archive, |
| 321 | else => |e| return e, |
| 322 | }; |
| 323 | defer archive.deinit(); |
| 324 | while (archive.objects.popOrNull()) |object| { |
| 325 | const index = @intCast(u16, self.objects.items.len); |
| 326 | try self.objects.append(self.allocator, object); |
| 327 | try self.updateMetadata(index); |
| 328 | } |
| 329 | continue; |
| 330 | } |
| 331 | |
| 332 | log.err("unexpected file type: expected object '.o' or archive '.a': {s}", .{file_name}); |
| 333 | return error.UnexpectedInputFileType; |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | fn mapAndUpdateSections( |
| 338 | self: *Zld, |
| 339 | object_id: u16, |
| 340 | source_sect_id: u16, |
| 341 | target_seg_id: u16, |
| 342 | target_sect_id: u16, |
| 343 | ) !void { |
| 344 | const object = self.objects.items[object_id]; |
| 345 | const source_seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 346 | const source_sect = source_seg.sections.items[source_sect_id]; |
| 347 | const target_seg = &self.load_commands.items[target_seg_id].Segment; |
| 348 | const target_sect = &target_seg.sections.items[target_sect_id]; |
| 349 | |
| 350 | const alignment = try math.powi(u32, 2, target_sect.@"align"); |
| 351 | const offset = mem.alignForwardGeneric(u64, target_sect.size, alignment); |
| 352 | const size = mem.alignForwardGeneric(u64, source_sect.size, alignment); |
| 353 | const key = MappingKey{ |
| 354 | .object_id = object_id, |
| 355 | .source_sect_id = source_sect_id, |
| 356 | }; |
| 357 | try self.mappings.putNoClobber(self.allocator, key, .{ |
| 358 | .source_sect_id = source_sect_id, |
| 359 | .target_seg_id = target_seg_id, |
| 360 | .target_sect_id = target_sect_id, |
| 361 | .offset = @intCast(u32, offset), |
| 362 | }); |
| 363 | log.debug("{s}: {s},{s} mapped to {s},{s} from 0x{x} to 0x{x}", .{ |
| 364 | object.name, |
| 365 | parseName(&source_sect.segname), |
| 366 | parseName(&source_sect.sectname), |
| 367 | parseName(&target_sect.segname), |
| 368 | parseName(&target_sect.sectname), |
| 369 | offset, |
| 370 | offset + size, |
| 371 | }); |
| 372 | |
| 373 | target_sect.size = offset + size; |
| 374 | } |
| 375 | |
| 376 | fn updateMetadata(self: *Zld, object_id: u16) !void { |
| 377 | const object = self.objects.items[object_id]; |
| 378 | const object_seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 379 | const text_seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 380 | const data_const_seg = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 381 | const data_seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 382 | |
| 383 | // Create missing metadata |
| 384 | for (object_seg.sections.items) |source_sect, id| { |
| 385 | if (id == object.text_section_index.?) continue; |
| 386 | const segname = parseName(&source_sect.segname); |
| 387 | const sectname = parseName(&source_sect.sectname); |
| 388 | const flags = source_sect.flags; |
| 389 | |
| 390 | switch (flags) { |
| 391 | macho.S_REGULAR, macho.S_4BYTE_LITERALS, macho.S_8BYTE_LITERALS, macho.S_16BYTE_LITERALS => { |
| 392 | if (mem.eql(u8, segname, "__TEXT")) { |
| 393 | if (self.text_const_section_index != null) continue; |
| 394 | |
| 395 | self.text_const_section_index = @intCast(u16, text_seg.sections.items.len); |
| 396 | try text_seg.addSection(self.allocator, .{ |
| 397 | .sectname = makeStaticString("__const"), |
| 398 | .segname = makeStaticString("__TEXT"), |
| 399 | .addr = 0, |
| 400 | .size = 0, |
| 401 | .offset = 0, |
| 402 | .@"align" = 0, |
| 403 | .reloff = 0, |
| 404 | .nreloc = 0, |
| 405 | .flags = macho.S_REGULAR, |
| 406 | .reserved1 = 0, |
| 407 | .reserved2 = 0, |
| 408 | .reserved3 = 0, |
| 409 | }); |
| 410 | } else if (mem.eql(u8, segname, "__DATA")) { |
| 411 | if (!mem.eql(u8, sectname, "__const")) continue; |
| 412 | if (self.data_const_section_index != null) continue; |
| 413 | |
| 414 | self.data_const_section_index = @intCast(u16, data_const_seg.sections.items.len); |
| 415 | try data_const_seg.addSection(self.allocator, .{ |
| 416 | .sectname = makeStaticString("__const"), |
| 417 | .segname = makeStaticString("__DATA_CONST"), |
| 418 | .addr = 0, |
| 419 | .size = 0, |
| 420 | .offset = 0, |
| 421 | .@"align" = 0, |
| 422 | .reloff = 0, |
| 423 | .nreloc = 0, |
| 424 | .flags = macho.S_REGULAR, |
| 425 | .reserved1 = 0, |
| 426 | .reserved2 = 0, |
| 427 | .reserved3 = 0, |
| 428 | }); |
| 429 | } |
| 430 | }, |
| 431 | macho.S_CSTRING_LITERALS => { |
| 432 | if (!mem.eql(u8, segname, "__TEXT")) continue; |
| 433 | if (self.cstring_section_index != null) continue; |
| 434 | |
| 435 | self.cstring_section_index = @intCast(u16, text_seg.sections.items.len); |
| 436 | try text_seg.addSection(self.allocator, .{ |
| 437 | .sectname = makeStaticString("__cstring"), |
| 438 | .segname = makeStaticString("__TEXT"), |
| 439 | .addr = 0, |
| 440 | .size = 0, |
| 441 | .offset = 0, |
| 442 | .@"align" = 0, |
| 443 | .reloff = 0, |
| 444 | .nreloc = 0, |
| 445 | .flags = macho.S_CSTRING_LITERALS, |
| 446 | .reserved1 = 0, |
| 447 | .reserved2 = 0, |
| 448 | .reserved3 = 0, |
| 449 | }); |
| 450 | }, |
| 451 | macho.S_ZEROFILL => { |
| 452 | if (!mem.eql(u8, segname, "__DATA")) continue; |
| 453 | if (self.bss_section_index != null) continue; |
| 454 | |
| 455 | self.bss_section_index = @intCast(u16, data_seg.sections.items.len); |
| 456 | try data_seg.addSection(self.allocator, .{ |
| 457 | .sectname = makeStaticString("__bss"), |
| 458 | .segname = makeStaticString("__DATA"), |
| 459 | .addr = 0, |
| 460 | .size = 0, |
| 461 | .offset = 0, |
| 462 | .@"align" = 0, |
| 463 | .reloff = 0, |
| 464 | .nreloc = 0, |
| 465 | .flags = macho.S_ZEROFILL, |
| 466 | .reserved1 = 0, |
| 467 | .reserved2 = 0, |
| 468 | .reserved3 = 0, |
| 469 | }); |
| 470 | }, |
| 471 | macho.S_THREAD_LOCAL_VARIABLES => { |
| 472 | if (!mem.eql(u8, segname, "__DATA")) continue; |
| 473 | if (self.tlv_section_index != null) continue; |
| 474 | |
| 475 | self.tlv_section_index = @intCast(u16, data_seg.sections.items.len); |
| 476 | try data_seg.addSection(self.allocator, .{ |
| 477 | .sectname = makeStaticString("__thread_vars"), |
| 478 | .segname = makeStaticString("__DATA"), |
| 479 | .addr = 0, |
| 480 | .size = 0, |
| 481 | .offset = 0, |
| 482 | .@"align" = 0, |
| 483 | .reloff = 0, |
| 484 | .nreloc = 0, |
| 485 | .flags = macho.S_THREAD_LOCAL_VARIABLES, |
| 486 | .reserved1 = 0, |
| 487 | .reserved2 = 0, |
| 488 | .reserved3 = 0, |
| 489 | }); |
| 490 | }, |
| 491 | macho.S_THREAD_LOCAL_REGULAR => { |
| 492 | if (!mem.eql(u8, segname, "__DATA")) continue; |
| 493 | if (self.tlv_data_section_index != null) continue; |
| 494 | |
| 495 | self.tlv_data_section_index = @intCast(u16, data_seg.sections.items.len); |
| 496 | try data_seg.addSection(self.allocator, .{ |
| 497 | .sectname = makeStaticString("__thread_data"), |
| 498 | .segname = makeStaticString("__DATA"), |
| 499 | .addr = 0, |
| 500 | .size = 0, |
| 501 | .offset = 0, |
| 502 | .@"align" = 0, |
| 503 | .reloff = 0, |
| 504 | .nreloc = 0, |
| 505 | .flags = macho.S_THREAD_LOCAL_REGULAR, |
| 506 | .reserved1 = 0, |
| 507 | .reserved2 = 0, |
| 508 | .reserved3 = 0, |
| 509 | }); |
| 510 | }, |
| 511 | macho.S_THREAD_LOCAL_ZEROFILL => { |
| 512 | if (!mem.eql(u8, segname, "__DATA")) continue; |
| 513 | if (self.tlv_bss_section_index != null) continue; |
| 514 | |
| 515 | self.tlv_bss_section_index = @intCast(u16, data_seg.sections.items.len); |
| 516 | try data_seg.addSection(self.allocator, .{ |
| 517 | .sectname = makeStaticString("__thread_bss"), |
| 518 | .segname = makeStaticString("__DATA"), |
| 519 | .addr = 0, |
| 520 | .size = 0, |
| 521 | .offset = 0, |
| 522 | .@"align" = 0, |
| 523 | .reloff = 0, |
| 524 | .nreloc = 0, |
| 525 | .flags = macho.S_THREAD_LOCAL_ZEROFILL, |
| 526 | .reserved1 = 0, |
| 527 | .reserved2 = 0, |
| 528 | .reserved3 = 0, |
| 529 | }); |
| 530 | }, |
| 531 | else => { |
| 532 | log.debug("unhandled section type 0x{x} for '{s}/{s}'", .{ flags, segname, sectname }); |
| 533 | }, |
| 534 | } |
| 535 | } |
| 536 | |
| 537 | // Find ideal section alignment. |
| 538 | for (object_seg.sections.items) |source_sect, id| { |
| 539 | if (self.getMatchingSection(source_sect)) |res| { |
| 540 | const target_seg = &self.load_commands.items[res.seg].Segment; |
| 541 | const target_sect = &target_seg.sections.items[res.sect]; |
| 542 | target_sect.@"align" = math.max(target_sect.@"align", source_sect.@"align"); |
| 543 | } |
| 544 | } |
| 545 | |
| 546 | // Update section mappings |
| 547 | for (object_seg.sections.items) |source_sect, id| { |
| 548 | const source_sect_id = @intCast(u16, id); |
| 549 | if (self.getMatchingSection(source_sect)) |res| { |
| 550 | try self.mapAndUpdateSections(object_id, source_sect_id, res.seg, res.sect); |
| 551 | continue; |
| 552 | } |
| 553 | |
| 554 | const segname = parseName(&source_sect.segname); |
| 555 | const sectname = parseName(&source_sect.sectname); |
| 556 | log.debug("section '{s}/{s}' will be unmapped", .{ segname, sectname }); |
| 557 | try self.unhandled_sections.putNoClobber(self.allocator, .{ |
| 558 | .object_id = object_id, |
| 559 | .source_sect_id = source_sect_id, |
| 560 | }, 0); |
| 561 | } |
| 562 | } |
| 563 | |
| 564 | const MatchingSection = struct { |
| 565 | seg: u16, |
| 566 | sect: u16, |
| 567 | }; |
| 568 | |
| 569 | fn getMatchingSection(self: *Zld, section: macho.section_64) ?MatchingSection { |
| 570 | const segname = parseName(§ion.segname); |
| 571 | const sectname = parseName(§ion.sectname); |
| 572 | const res: ?MatchingSection = blk: { |
| 573 | switch (section.flags) { |
| 574 | macho.S_4BYTE_LITERALS, macho.S_8BYTE_LITERALS, macho.S_16BYTE_LITERALS => { |
| 575 | break :blk .{ |
| 576 | .seg = self.text_segment_cmd_index.?, |
| 577 | .sect = self.text_const_section_index.?, |
| 578 | }; |
| 579 | }, |
| 580 | macho.S_CSTRING_LITERALS => { |
| 581 | break :blk .{ |
| 582 | .seg = self.text_segment_cmd_index.?, |
| 583 | .sect = self.cstring_section_index.?, |
| 584 | }; |
| 585 | }, |
| 586 | macho.S_ZEROFILL => { |
| 587 | break :blk .{ |
| 588 | .seg = self.data_segment_cmd_index.?, |
| 589 | .sect = self.bss_section_index.?, |
| 590 | }; |
| 591 | }, |
| 592 | macho.S_THREAD_LOCAL_VARIABLES => { |
| 593 | break :blk .{ |
| 594 | .seg = self.data_segment_cmd_index.?, |
| 595 | .sect = self.tlv_section_index.?, |
| 596 | }; |
| 597 | }, |
| 598 | macho.S_THREAD_LOCAL_REGULAR => { |
| 599 | break :blk .{ |
| 600 | .seg = self.data_segment_cmd_index.?, |
| 601 | .sect = self.tlv_data_section_index.?, |
| 602 | }; |
| 603 | }, |
| 604 | macho.S_THREAD_LOCAL_ZEROFILL => { |
| 605 | break :blk .{ |
| 606 | .seg = self.data_segment_cmd_index.?, |
| 607 | .sect = self.tlv_bss_section_index.?, |
| 608 | }; |
| 609 | }, |
| 610 | macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS => { |
| 611 | break :blk .{ |
| 612 | .seg = self.text_segment_cmd_index.?, |
| 613 | .sect = self.text_section_index.?, |
| 614 | }; |
| 615 | }, |
| 616 | macho.S_REGULAR => { |
| 617 | if (mem.eql(u8, segname, "__TEXT")) { |
| 618 | break :blk .{ |
| 619 | .seg = self.text_segment_cmd_index.?, |
| 620 | .sect = self.text_const_section_index.?, |
| 621 | }; |
| 622 | } else if (mem.eql(u8, segname, "__DATA")) { |
| 623 | if (mem.eql(u8, sectname, "__data")) { |
| 624 | break :blk .{ |
| 625 | .seg = self.data_segment_cmd_index.?, |
| 626 | .sect = self.data_section_index.?, |
| 627 | }; |
| 628 | } else if (mem.eql(u8, sectname, "__const")) { |
| 629 | break :blk .{ |
| 630 | .seg = self.data_const_segment_cmd_index.?, |
| 631 | .sect = self.data_const_section_index.?, |
| 632 | }; |
| 633 | } |
| 634 | } |
| 635 | break :blk null; |
| 636 | }, |
| 637 | else => { |
| 638 | break :blk null; |
| 639 | }, |
| 640 | } |
| 641 | }; |
| 642 | return res; |
| 643 | } |
| 644 | |
| 645 | fn sortSections(self: *Zld) !void { |
| 646 | var text_index_mapping = std.AutoHashMap(u16, u16).init(self.allocator); |
| 647 | defer text_index_mapping.deinit(); |
| 648 | var data_const_index_mapping = std.AutoHashMap(u16, u16).init(self.allocator); |
| 649 | defer data_const_index_mapping.deinit(); |
| 650 | var data_index_mapping = std.AutoHashMap(u16, u16).init(self.allocator); |
| 651 | defer data_index_mapping.deinit(); |
| 652 | |
| 653 | { |
| 654 | // __TEXT segment |
| 655 | const seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 656 | var sections = seg.sections.toOwnedSlice(self.allocator); |
| 657 | defer self.allocator.free(sections); |
| 658 | try seg.sections.ensureCapacity(self.allocator, sections.len); |
| 659 | |
| 660 | const indices = &[_]*?u16{ |
| 661 | &self.text_section_index, |
| 662 | &self.stubs_section_index, |
| 663 | &self.stub_helper_section_index, |
| 664 | &self.text_const_section_index, |
| 665 | &self.cstring_section_index, |
| 666 | }; |
| 667 | for (indices) |maybe_index| { |
| 668 | const new_index: u16 = if (maybe_index.*) |index| blk: { |
| 669 | const idx = @intCast(u16, seg.sections.items.len); |
| 670 | seg.sections.appendAssumeCapacity(sections[index]); |
| 671 | try text_index_mapping.putNoClobber(index, idx); |
| 672 | break :blk idx; |
| 673 | } else continue; |
| 674 | maybe_index.* = new_index; |
| 675 | } |
| 676 | } |
| 677 | |
| 678 | { |
| 679 | // __DATA_CONST segment |
| 680 | const seg = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 681 | var sections = seg.sections.toOwnedSlice(self.allocator); |
| 682 | defer self.allocator.free(sections); |
| 683 | try seg.sections.ensureCapacity(self.allocator, sections.len); |
| 684 | |
| 685 | const indices = &[_]*?u16{ |
| 686 | &self.got_section_index, |
| 687 | &self.data_const_section_index, |
| 688 | }; |
| 689 | for (indices) |maybe_index| { |
| 690 | const new_index: u16 = if (maybe_index.*) |index| blk: { |
| 691 | const idx = @intCast(u16, seg.sections.items.len); |
| 692 | seg.sections.appendAssumeCapacity(sections[index]); |
| 693 | try data_const_index_mapping.putNoClobber(index, idx); |
| 694 | break :blk idx; |
| 695 | } else continue; |
| 696 | maybe_index.* = new_index; |
| 697 | } |
| 698 | } |
| 699 | |
| 700 | { |
| 701 | // __DATA segment |
| 702 | const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 703 | var sections = seg.sections.toOwnedSlice(self.allocator); |
| 704 | defer self.allocator.free(sections); |
| 705 | try seg.sections.ensureCapacity(self.allocator, sections.len); |
| 706 | |
| 707 | // __DATA segment |
| 708 | const indices = &[_]*?u16{ |
| 709 | &self.la_symbol_ptr_section_index, |
| 710 | &self.tlv_section_index, |
| 711 | &self.data_section_index, |
| 712 | &self.tlv_data_section_index, |
| 713 | &self.tlv_bss_section_index, |
| 714 | &self.bss_section_index, |
| 715 | }; |
| 716 | for (indices) |maybe_index| { |
| 717 | const new_index: u16 = if (maybe_index.*) |index| blk: { |
| 718 | const idx = @intCast(u16, seg.sections.items.len); |
| 719 | seg.sections.appendAssumeCapacity(sections[index]); |
| 720 | try data_index_mapping.putNoClobber(index, idx); |
| 721 | break :blk idx; |
| 722 | } else continue; |
| 723 | maybe_index.* = new_index; |
| 724 | } |
| 725 | } |
| 726 | |
| 727 | var it = self.mappings.iterator(); |
| 728 | while (it.next()) |entry| { |
| 729 | const mapping = &entry.value; |
| 730 | if (self.text_segment_cmd_index.? == mapping.target_seg_id) { |
| 731 | const new_index = text_index_mapping.get(mapping.target_sect_id) orelse unreachable; |
| 732 | mapping.target_sect_id = new_index; |
| 733 | } else if (self.data_const_segment_cmd_index.? == mapping.target_seg_id) { |
| 734 | const new_index = data_const_index_mapping.get(mapping.target_sect_id) orelse unreachable; |
| 735 | mapping.target_sect_id = new_index; |
| 736 | } else if (self.data_segment_cmd_index.? == mapping.target_seg_id) { |
| 737 | const new_index = data_index_mapping.get(mapping.target_sect_id) orelse unreachable; |
| 738 | mapping.target_sect_id = new_index; |
| 739 | } else unreachable; |
| 740 | } |
| 741 | } |
| 742 | |
| 743 | fn resolveImports(self: *Zld) !void { |
| 744 | var imports = std.StringArrayHashMap(bool).init(self.allocator); |
| 745 | defer imports.deinit(); |
| 746 | |
| 747 | for (self.objects.items) |object| { |
| 748 | for (object.symtab.items) |sym| { |
| 749 | if (isLocal(&sym)) continue; |
| 750 | |
| 751 | const name = object.getString(sym.n_strx); |
| 752 | const res = try imports.getOrPut(name); |
| 753 | if (isExport(&sym)) { |
| 754 | res.entry.value = false; |
| 755 | continue; |
| 756 | } |
| 757 | if (res.found_existing and !res.entry.value) |
| 758 | continue; |
| 759 | res.entry.value = true; |
| 760 | } |
| 761 | } |
| 762 | |
| 763 | for (imports.items()) |entry| { |
| 764 | if (!entry.value) continue; |
| 765 | |
| 766 | const sym_name = entry.key; |
| 767 | const n_strx = try self.makeString(sym_name); |
| 768 | var new_sym: macho.nlist_64 = .{ |
| 769 | .n_strx = n_strx, |
| 770 | .n_type = macho.N_UNDF | macho.N_EXT, |
| 771 | .n_value = 0, |
| 772 | .n_desc = macho.REFERENCE_FLAG_UNDEFINED_NON_LAZY | macho.N_SYMBOL_RESOLVER, |
| 773 | .n_sect = 0, |
| 774 | }; |
| 775 | var key = try self.allocator.dupe(u8, sym_name); |
| 776 | // TODO handle symbol resolution from non-libc dylibs. |
| 777 | const dylib_ordinal = 1; |
| 778 | |
| 779 | // TODO need to rework this. Perhaps should create a set of all possible libc |
| 780 | // symbols which are expected to be nonlazy? |
| 781 | if (mem.eql(u8, sym_name, "___stdoutp") or |
| 782 | mem.eql(u8, sym_name, "___stderrp") or |
| 783 | mem.eql(u8, sym_name, "___stdinp") or |
| 784 | mem.eql(u8, sym_name, "___stack_chk_guard") or |
| 785 | mem.eql(u8, sym_name, "_environ") or |
| 786 | mem.eql(u8, sym_name, "__DefaultRuneLocale") or |
| 787 | mem.eql(u8, sym_name, "_mach_task_self_")) |
| 788 | { |
| 789 | log.debug("writing nonlazy symbol '{s}'", .{sym_name}); |
| 790 | const index = @intCast(u32, self.nonlazy_imports.items().len); |
| 791 | try self.nonlazy_imports.putNoClobber(self.allocator, key, .{ |
| 792 | .symbol = new_sym, |
| 793 | .dylib_ordinal = dylib_ordinal, |
| 794 | .index = index, |
| 795 | }); |
| 796 | } else if (mem.eql(u8, sym_name, "__tlv_bootstrap")) { |
| 797 | log.debug("writing threadlocal symbol '{s}'", .{sym_name}); |
| 798 | self.tlv_bootstrap = .{ |
| 799 | .symbol = new_sym, |
| 800 | .dylib_ordinal = dylib_ordinal, |
| 801 | .index = 0, |
| 802 | }; |
| 803 | } else { |
| 804 | log.debug("writing lazy symbol '{s}'", .{sym_name}); |
| 805 | const index = @intCast(u32, self.lazy_imports.items().len); |
| 806 | try self.lazy_imports.putNoClobber(self.allocator, key, .{ |
| 807 | .symbol = new_sym, |
| 808 | .dylib_ordinal = dylib_ordinal, |
| 809 | .index = index, |
| 810 | }); |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | const n_strx = try self.makeString("dyld_stub_binder"); |
| 815 | const name = try self.allocator.dupe(u8, "dyld_stub_binder"); |
| 816 | log.debug("writing nonlazy symbol 'dyld_stub_binder'", .{}); |
| 817 | const index = @intCast(u32, self.nonlazy_imports.items().len); |
| 818 | try self.nonlazy_imports.putNoClobber(self.allocator, name, .{ |
| 819 | .symbol = .{ |
| 820 | .n_strx = n_strx, |
| 821 | .n_type = std.macho.N_UNDF | std.macho.N_EXT, |
| 822 | .n_sect = 0, |
| 823 | .n_desc = std.macho.REFERENCE_FLAG_UNDEFINED_NON_LAZY | std.macho.N_SYMBOL_RESOLVER, |
| 824 | .n_value = 0, |
| 825 | }, |
| 826 | .dylib_ordinal = 1, |
| 827 | .index = index, |
| 828 | }); |
| 829 | } |
| 830 | |
| 831 | fn allocateTextSegment(self: *Zld) !void { |
| 832 | const seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 833 | const nexterns = @intCast(u32, self.lazy_imports.items().len); |
| 834 | |
| 835 | const base_vmaddr = self.load_commands.items[self.pagezero_segment_cmd_index.?].Segment.inner.vmsize; |
| 836 | seg.inner.fileoff = 0; |
| 837 | seg.inner.vmaddr = base_vmaddr; |
| 838 | |
| 839 | // Set stubs and stub_helper sizes |
| 840 | const stubs = &seg.sections.items[self.stubs_section_index.?]; |
| 841 | const stub_helper = &seg.sections.items[self.stub_helper_section_index.?]; |
| 842 | stubs.size += nexterns * stubs.reserved2; |
| 843 | |
| 844 | const stub_size: u4 = switch (self.arch.?) { |
| 845 | .x86_64 => 10, |
| 846 | .aarch64 => 3 * @sizeOf(u32), |
| 847 | else => unreachable, |
| 848 | }; |
| 849 | stub_helper.size += nexterns * stub_size; |
| 850 | |
| 851 | var sizeofcmds: u64 = 0; |
| 852 | for (self.load_commands.items) |lc| { |
| 853 | sizeofcmds += lc.cmdsize(); |
| 854 | } |
| 855 | |
| 856 | try self.allocateSegment(self.text_segment_cmd_index.?, @sizeOf(macho.mach_header_64) + sizeofcmds); |
| 857 | |
| 858 | // Shift all sections to the back to minimize jump size between __TEXT and __DATA segments. |
| 859 | var min_alignment: u32 = 0; |
| 860 | for (seg.sections.items) |sect| { |
| 861 | const alignment = try math.powi(u32, 2, sect.@"align"); |
| 862 | min_alignment = math.max(min_alignment, alignment); |
| 863 | } |
| 864 | |
| 865 | assert(min_alignment > 0); |
| 866 | const last_sect_idx = seg.sections.items.len - 1; |
| 867 | const last_sect = seg.sections.items[last_sect_idx]; |
| 868 | const shift: u32 = blk: { |
| 869 | const diff = seg.inner.filesize - last_sect.offset - last_sect.size; |
| 870 | const factor = @divTrunc(diff, min_alignment); |
| 871 | break :blk @intCast(u32, factor * min_alignment); |
| 872 | }; |
| 873 | |
| 874 | if (shift > 0) { |
| 875 | for (seg.sections.items) |*sect| { |
| 876 | sect.offset += shift; |
| 877 | sect.addr += shift; |
| 878 | } |
| 879 | } |
| 880 | } |
| 881 | |
| 882 | fn allocateDataConstSegment(self: *Zld) !void { |
| 883 | const seg = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 884 | const nonlazy = @intCast(u32, self.nonlazy_imports.items().len); |
| 885 | |
| 886 | const text_seg = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 887 | seg.inner.fileoff = text_seg.inner.fileoff + text_seg.inner.filesize; |
| 888 | seg.inner.vmaddr = text_seg.inner.vmaddr + text_seg.inner.vmsize; |
| 889 | |
| 890 | // Set got size |
| 891 | const got = &seg.sections.items[self.got_section_index.?]; |
| 892 | // TODO this will require scanning the relocations at least one to work out |
| 893 | // the exact amount of local GOT indirections. For the time being, set some |
| 894 | // default value. |
| 895 | got.size += (max_local_got_indirections + nonlazy) * @sizeOf(u64); |
| 896 | |
| 897 | try self.allocateSegment(self.data_const_segment_cmd_index.?, 0); |
| 898 | } |
| 899 | |
| 900 | fn allocateDataSegment(self: *Zld) !void { |
| 901 | const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 902 | const lazy = @intCast(u32, self.lazy_imports.items().len); |
| 903 | |
| 904 | const data_const_seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 905 | seg.inner.fileoff = data_const_seg.inner.fileoff + data_const_seg.inner.filesize; |
| 906 | seg.inner.vmaddr = data_const_seg.inner.vmaddr + data_const_seg.inner.vmsize; |
| 907 | |
| 908 | // Set la_symbol_ptr and data size |
| 909 | const la_symbol_ptr = &seg.sections.items[self.la_symbol_ptr_section_index.?]; |
| 910 | const data = &seg.sections.items[self.data_section_index.?]; |
| 911 | la_symbol_ptr.size += lazy * @sizeOf(u64); |
| 912 | data.size += @sizeOf(u64); // TODO when do we need more? |
| 913 | |
| 914 | try self.allocateSegment(self.data_segment_cmd_index.?, 0); |
| 915 | } |
| 916 | |
| 917 | fn allocateLinkeditSegment(self: *Zld) void { |
| 918 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 919 | const data_seg = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 920 | seg.inner.fileoff = data_seg.inner.fileoff + data_seg.inner.filesize; |
| 921 | seg.inner.vmaddr = data_seg.inner.vmaddr + data_seg.inner.vmsize; |
| 922 | } |
| 923 | |
| 924 | fn allocateSegment(self: *Zld, index: u16, offset: u64) !void { |
| 925 | const base_vmaddr = self.load_commands.items[self.pagezero_segment_cmd_index.?].Segment.inner.vmsize; |
| 926 | const seg = &self.load_commands.items[index].Segment; |
| 927 | |
| 928 | // Allocate the sections according to their alignment at the beginning of the segment. |
| 929 | var start: u64 = offset; |
| 930 | for (seg.sections.items) |*sect| { |
| 931 | const alignment = try math.powi(u32, 2, sect.@"align"); |
| 932 | const start_aligned = mem.alignForwardGeneric(u64, start, alignment); |
| 933 | const end_aligned = mem.alignForwardGeneric(u64, start_aligned + sect.size, alignment); |
| 934 | sect.offset = @intCast(u32, seg.inner.fileoff + start_aligned); |
| 935 | sect.addr = seg.inner.vmaddr + start_aligned; |
| 936 | start = end_aligned; |
| 937 | } |
| 938 | |
| 939 | const seg_size_aligned = mem.alignForwardGeneric(u64, start, self.page_size.?); |
| 940 | seg.inner.filesize = seg_size_aligned; |
| 941 | seg.inner.vmsize = seg_size_aligned; |
| 942 | } |
| 943 | |
| 944 | fn writeStubHelperCommon(self: *Zld) !void { |
| 945 | const text_segment = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 946 | const stub_helper = &text_segment.sections.items[self.stub_helper_section_index.?]; |
| 947 | const data_const_segment = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 948 | const got = &data_const_segment.sections.items[self.got_section_index.?]; |
| 949 | const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 950 | const data = &data_segment.sections.items[self.data_section_index.?]; |
| 951 | const la_symbol_ptr = data_segment.sections.items[self.la_symbol_ptr_section_index.?]; |
| 952 | |
| 953 | self.stub_helper_stubs_start_off = blk: { |
| 954 | switch (self.arch.?) { |
| 955 | .x86_64 => { |
| 956 | const code_size = 15; |
| 957 | var code: [code_size]u8 = undefined; |
| 958 | // lea %r11, [rip + disp] |
| 959 | code[0] = 0x4c; |
| 960 | code[1] = 0x8d; |
| 961 | code[2] = 0x1d; |
| 962 | { |
| 963 | const target_addr = data.addr + data.size - @sizeOf(u64); |
| 964 | const displacement = try math.cast(u32, target_addr - stub_helper.addr - 7); |
| 965 | mem.writeIntLittle(u32, code[3..7], displacement); |
| 966 | } |
| 967 | // push %r11 |
| 968 | code[7] = 0x41; |
| 969 | code[8] = 0x53; |
| 970 | // jmp [rip + disp] |
| 971 | code[9] = 0xff; |
| 972 | code[10] = 0x25; |
| 973 | { |
| 974 | const dyld_stub_binder = self.nonlazy_imports.get("dyld_stub_binder").?; |
| 975 | const addr = (got.addr + dyld_stub_binder.index * @sizeOf(u64)); |
| 976 | const displacement = try math.cast(u32, addr - stub_helper.addr - code_size); |
| 977 | mem.writeIntLittle(u32, code[11..], displacement); |
| 978 | } |
| 979 | try self.file.?.pwriteAll(&code, stub_helper.offset); |
| 980 | break :blk stub_helper.offset + code_size; |
| 981 | }, |
| 982 | .aarch64 => { |
| 983 | var code: [6 * @sizeOf(u32)]u8 = undefined; |
| 984 | data_blk_outer: { |
| 985 | const this_addr = stub_helper.addr; |
| 986 | const target_addr = data.addr + data.size - @sizeOf(u64); |
| 987 | data_blk: { |
| 988 | const displacement = math.cast(i21, target_addr - this_addr) catch |_| break :data_blk; |
| 989 | // adr x17, disp |
| 990 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.adr(.x17, displacement).toU32()); |
| 991 | // nop |
| 992 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.nop().toU32()); |
| 993 | break :data_blk_outer; |
| 994 | } |
| 995 | data_blk: { |
| 996 | const new_this_addr = this_addr + @sizeOf(u32); |
| 997 | const displacement = math.cast(i21, target_addr - new_this_addr) catch |_| break :data_blk; |
| 998 | // nop |
| 999 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.nop().toU32()); |
| 1000 | // adr x17, disp |
| 1001 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.adr(.x17, displacement).toU32()); |
| 1002 | break :data_blk_outer; |
| 1003 | } |
| 1004 | // Jump is too big, replace adr with adrp and add. |
| 1005 | const this_page = @intCast(i32, this_addr >> 12); |
| 1006 | const target_page = @intCast(i32, target_addr >> 12); |
| 1007 | const pages = @intCast(i21, target_page - this_page); |
| 1008 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.adrp(.x17, pages).toU32()); |
| 1009 | const narrowed = @truncate(u12, target_addr); |
| 1010 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.add(.x17, .x17, narrowed, false).toU32()); |
| 1011 | } |
| 1012 | // stp x16, x17, [sp, #-16]! |
| 1013 | code[8] = 0xf0; |
| 1014 | code[9] = 0x47; |
| 1015 | code[10] = 0xbf; |
| 1016 | code[11] = 0xa9; |
| 1017 | binder_blk_outer: { |
| 1018 | const dyld_stub_binder = self.nonlazy_imports.get("dyld_stub_binder").?; |
| 1019 | const this_addr = stub_helper.addr + 3 * @sizeOf(u32); |
| 1020 | const target_addr = (got.addr + dyld_stub_binder.index * @sizeOf(u64)); |
| 1021 | binder_blk: { |
| 1022 | const displacement = math.divExact(u64, target_addr - this_addr, 4) catch |_| break :binder_blk; |
| 1023 | const literal = math.cast(u18, displacement) catch |_| break :binder_blk; |
| 1024 | // ldr x16, label |
| 1025 | mem.writeIntLittle(u32, code[12..16], aarch64.Instruction.ldr(.x16, .{ |
| 1026 | .literal = literal, |
| 1027 | }).toU32()); |
| 1028 | // nop |
| 1029 | mem.writeIntLittle(u32, code[16..20], aarch64.Instruction.nop().toU32()); |
| 1030 | break :binder_blk_outer; |
| 1031 | } |
| 1032 | binder_blk: { |
| 1033 | const new_this_addr = this_addr + @sizeOf(u32); |
| 1034 | const displacement = math.divExact(u64, target_addr - new_this_addr, 4) catch |_| break :binder_blk; |
| 1035 | const literal = math.cast(u18, displacement) catch |_| break :binder_blk; |
| 1036 | log.debug("2: disp=0x{x}, literal=0x{x}", .{ displacement, literal }); |
| 1037 | // Pad with nop to please division. |
| 1038 | // nop |
| 1039 | mem.writeIntLittle(u32, code[12..16], aarch64.Instruction.nop().toU32()); |
| 1040 | // ldr x16, label |
| 1041 | mem.writeIntLittle(u32, code[16..20], aarch64.Instruction.ldr(.x16, .{ |
| 1042 | .literal = literal, |
| 1043 | }).toU32()); |
| 1044 | break :binder_blk_outer; |
| 1045 | } |
| 1046 | // Use adrp followed by ldr(immediate). |
| 1047 | const this_page = @intCast(i32, this_addr >> 12); |
| 1048 | const target_page = @intCast(i32, target_addr >> 12); |
| 1049 | const pages = @intCast(i21, target_page - this_page); |
| 1050 | mem.writeIntLittle(u32, code[12..16], aarch64.Instruction.adrp(.x16, pages).toU32()); |
| 1051 | const narrowed = @truncate(u12, target_addr); |
| 1052 | const offset = try math.divExact(u12, narrowed, 8); |
| 1053 | mem.writeIntLittle(u32, code[16..20], aarch64.Instruction.ldr(.x16, .{ |
| 1054 | .register = .{ |
| 1055 | .rn = .x16, |
| 1056 | .offset = aarch64.Instruction.LoadStoreOffset.imm(offset), |
| 1057 | }, |
| 1058 | }).toU32()); |
| 1059 | } |
| 1060 | // br x16 |
| 1061 | code[20] = 0x00; |
| 1062 | code[21] = 0x02; |
| 1063 | code[22] = 0x1f; |
| 1064 | code[23] = 0xd6; |
| 1065 | try self.file.?.pwriteAll(&code, stub_helper.offset); |
| 1066 | break :blk stub_helper.offset + 6 * @sizeOf(u32); |
| 1067 | }, |
| 1068 | else => unreachable, |
| 1069 | } |
| 1070 | }; |
| 1071 | |
| 1072 | for (self.lazy_imports.items()) |_, i| { |
| 1073 | const index = @intCast(u32, i); |
| 1074 | try self.writeLazySymbolPointer(index); |
| 1075 | try self.writeStub(index); |
| 1076 | try self.writeStubInStubHelper(index); |
| 1077 | } |
| 1078 | } |
| 1079 | |
| 1080 | fn writeLazySymbolPointer(self: *Zld, index: u32) !void { |
| 1081 | const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 1082 | const stub_helper = text_segment.sections.items[self.stub_helper_section_index.?]; |
| 1083 | const data_segment = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 1084 | const la_symbol_ptr = data_segment.sections.items[self.la_symbol_ptr_section_index.?]; |
| 1085 | |
| 1086 | const stub_size: u4 = switch (self.arch.?) { |
| 1087 | .x86_64 => 10, |
| 1088 | .aarch64 => 3 * @sizeOf(u32), |
| 1089 | else => unreachable, |
| 1090 | }; |
| 1091 | const stub_off = self.stub_helper_stubs_start_off.? + index * stub_size; |
| 1092 | const end = stub_helper.addr + stub_off - stub_helper.offset; |
| 1093 | var buf: [@sizeOf(u64)]u8 = undefined; |
| 1094 | mem.writeIntLittle(u64, &buf, end); |
| 1095 | const off = la_symbol_ptr.offset + index * @sizeOf(u64); |
| 1096 | log.debug("writing lazy symbol pointer entry 0x{x} at 0x{x}", .{ end, off }); |
| 1097 | try self.file.?.pwriteAll(&buf, off); |
| 1098 | } |
| 1099 | |
| 1100 | fn writeStub(self: *Zld, index: u32) !void { |
| 1101 | const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 1102 | const stubs = text_segment.sections.items[self.stubs_section_index.?]; |
| 1103 | const data_segment = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 1104 | const la_symbol_ptr = data_segment.sections.items[self.la_symbol_ptr_section_index.?]; |
| 1105 | |
| 1106 | const stub_off = stubs.offset + index * stubs.reserved2; |
| 1107 | const stub_addr = stubs.addr + index * stubs.reserved2; |
| 1108 | const la_ptr_addr = la_symbol_ptr.addr + index * @sizeOf(u64); |
| 1109 | log.debug("writing stub at 0x{x}", .{stub_off}); |
| 1110 | var code = try self.allocator.alloc(u8, stubs.reserved2); |
| 1111 | defer self.allocator.free(code); |
| 1112 | switch (self.arch.?) { |
| 1113 | .x86_64 => { |
| 1114 | assert(la_ptr_addr >= stub_addr + stubs.reserved2); |
| 1115 | const displacement = try math.cast(u32, la_ptr_addr - stub_addr - stubs.reserved2); |
| 1116 | // jmp |
| 1117 | code[0] = 0xff; |
| 1118 | code[1] = 0x25; |
| 1119 | mem.writeIntLittle(u32, code[2..][0..4], displacement); |
| 1120 | }, |
| 1121 | .aarch64 => { |
| 1122 | assert(la_ptr_addr >= stub_addr); |
| 1123 | outer: { |
| 1124 | const this_addr = stub_addr; |
| 1125 | const target_addr = la_ptr_addr; |
| 1126 | inner: { |
| 1127 | const displacement = math.divExact(u64, target_addr - this_addr, 4) catch |_| break :inner; |
| 1128 | const literal = math.cast(u18, displacement) catch |_| break :inner; |
| 1129 | // ldr x16, literal |
| 1130 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.ldr(.x16, .{ |
| 1131 | .literal = literal, |
| 1132 | }).toU32()); |
| 1133 | // nop |
| 1134 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.nop().toU32()); |
| 1135 | break :outer; |
| 1136 | } |
| 1137 | inner: { |
| 1138 | const new_this_addr = this_addr + @sizeOf(u32); |
| 1139 | const displacement = math.divExact(u64, target_addr - new_this_addr, 4) catch |_| break :inner; |
| 1140 | const literal = math.cast(u18, displacement) catch |_| break :inner; |
| 1141 | // nop |
| 1142 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.nop().toU32()); |
| 1143 | // ldr x16, literal |
| 1144 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.ldr(.x16, .{ |
| 1145 | .literal = literal, |
| 1146 | }).toU32()); |
| 1147 | break :outer; |
| 1148 | } |
| 1149 | // Use adrp followed by ldr(immediate). |
| 1150 | const this_page = @intCast(i32, this_addr >> 12); |
| 1151 | const target_page = @intCast(i32, target_addr >> 12); |
| 1152 | const pages = @intCast(i21, target_page - this_page); |
| 1153 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.adrp(.x16, pages).toU32()); |
| 1154 | const narrowed = @truncate(u12, target_addr); |
| 1155 | const offset = try math.divExact(u12, narrowed, 8); |
| 1156 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.ldr(.x16, .{ |
| 1157 | .register = .{ |
| 1158 | .rn = .x16, |
| 1159 | .offset = aarch64.Instruction.LoadStoreOffset.imm(offset), |
| 1160 | }, |
| 1161 | }).toU32()); |
| 1162 | } |
| 1163 | // br x16 |
| 1164 | mem.writeIntLittle(u32, code[8..12], aarch64.Instruction.br(.x16).toU32()); |
| 1165 | }, |
| 1166 | else => unreachable, |
| 1167 | } |
| 1168 | try self.file.?.pwriteAll(code, stub_off); |
| 1169 | } |
| 1170 | |
| 1171 | fn writeStubInStubHelper(self: *Zld, index: u32) !void { |
| 1172 | const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 1173 | const stub_helper = text_segment.sections.items[self.stub_helper_section_index.?]; |
| 1174 | |
| 1175 | const stub_size: u4 = switch (self.arch.?) { |
| 1176 | .x86_64 => 10, |
| 1177 | .aarch64 => 3 * @sizeOf(u32), |
| 1178 | else => unreachable, |
| 1179 | }; |
| 1180 | const stub_off = self.stub_helper_stubs_start_off.? + index * stub_size; |
| 1181 | var code = try self.allocator.alloc(u8, stub_size); |
| 1182 | defer self.allocator.free(code); |
| 1183 | switch (self.arch.?) { |
| 1184 | .x86_64 => { |
| 1185 | const displacement = try math.cast( |
| 1186 | i32, |
| 1187 | @intCast(i64, stub_helper.offset) - @intCast(i64, stub_off) - stub_size, |
| 1188 | ); |
| 1189 | // pushq |
| 1190 | code[0] = 0x68; |
| 1191 | mem.writeIntLittle(u32, code[1..][0..4], 0x0); // Just a placeholder populated in `populateLazyBindOffsetsInStubHelper`. |
| 1192 | // jmpq |
| 1193 | code[5] = 0xe9; |
| 1194 | mem.writeIntLittle(u32, code[6..][0..4], @bitCast(u32, displacement)); |
| 1195 | }, |
| 1196 | .aarch64 => { |
| 1197 | const displacement = try math.cast(i28, @intCast(i64, stub_helper.offset) - @intCast(i64, stub_off) - 4); |
| 1198 | const literal = @divExact(stub_size - @sizeOf(u32), 4); |
| 1199 | // ldr w16, literal |
| 1200 | mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.ldr(.w16, .{ |
| 1201 | .literal = literal, |
| 1202 | }).toU32()); |
| 1203 | // b disp |
| 1204 | mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.b(displacement).toU32()); |
| 1205 | mem.writeIntLittle(u32, code[8..12], 0x0); // Just a placeholder populated in `populateLazyBindOffsetsInStubHelper`. |
| 1206 | }, |
| 1207 | else => unreachable, |
| 1208 | } |
| 1209 | try self.file.?.pwriteAll(code, stub_off); |
| 1210 | } |
| 1211 | |
| 1212 | fn resolveSymbols(self: *Zld) !void { |
| 1213 | for (self.objects.items) |object, object_id| { |
| 1214 | const seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 1215 | log.debug("\n\n", .{}); |
| 1216 | log.debug("resolving symbols in {s}", .{object.name}); |
| 1217 | |
| 1218 | for (object.symtab.items) |sym| { |
| 1219 | if (isImport(&sym)) continue; |
| 1220 | |
| 1221 | const sym_name = object.getString(sym.n_strx); |
| 1222 | const out_name = try self.allocator.dupe(u8, sym_name); |
| 1223 | const locs = try self.locals.getOrPut(self.allocator, out_name); |
| 1224 | defer { |
| 1225 | if (locs.found_existing) self.allocator.free(out_name); |
| 1226 | } |
| 1227 | |
| 1228 | if (!locs.found_existing) { |
| 1229 | locs.entry.value = .{}; |
| 1230 | } |
| 1231 | |
| 1232 | const tt: Symbol.Type = blk: { |
| 1233 | if (isLocal(&sym)) { |
| 1234 | break :blk .Local; |
| 1235 | } else if (isWeakDef(&sym)) { |
| 1236 | break :blk .WeakGlobal; |
| 1237 | } else { |
| 1238 | break :blk .Global; |
| 1239 | } |
| 1240 | }; |
| 1241 | if (tt == .Global) { |
| 1242 | for (locs.entry.value.items) |ss| { |
| 1243 | if (ss.tt == .Global) { |
| 1244 | log.debug("symbol already defined '{s}'", .{sym_name}); |
| 1245 | continue; |
| 1246 | // log.err("symbol '{s}' defined multiple times: {}", .{ sym_name, sym }); |
| 1247 | // return error.MultipleSymbolDefinitions; |
| 1248 | } |
| 1249 | } |
| 1250 | } |
| 1251 | |
| 1252 | const source_sect_id = sym.n_sect - 1; |
| 1253 | const target_mapping = self.mappings.get(.{ |
| 1254 | .object_id = @intCast(u16, object_id), |
| 1255 | .source_sect_id = source_sect_id, |
| 1256 | }) orelse { |
| 1257 | if (self.unhandled_sections.get(.{ |
| 1258 | .object_id = @intCast(u16, object_id), |
| 1259 | .source_sect_id = source_sect_id, |
| 1260 | }) != null) continue; |
| 1261 | |
| 1262 | log.err("section not mapped for symbol '{s}': {}", .{ sym_name, sym }); |
| 1263 | return error.SectionNotMappedForSymbol; |
| 1264 | }; |
| 1265 | const source_sect = seg.sections.items[source_sect_id]; |
| 1266 | const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment; |
| 1267 | const target_sect = target_seg.sections.items[target_mapping.target_sect_id]; |
| 1268 | const target_addr = target_sect.addr + target_mapping.offset; |
| 1269 | const n_value = sym.n_value - source_sect.addr + target_addr; |
| 1270 | |
| 1271 | log.debug("resolving '{s}':{} as {s} symbol at 0x{x}", .{ sym_name, sym, tt, n_value }); |
| 1272 | |
| 1273 | // TODO there might be a more generic way of doing this. |
| 1274 | var n_sect: u16 = 0; |
| 1275 | for (self.load_commands.items) |cmd, cmd_id| { |
| 1276 | if (cmd != .Segment) break; |
| 1277 | if (cmd_id == target_mapping.target_seg_id) { |
| 1278 | n_sect += target_mapping.target_sect_id + 1; |
| 1279 | break; |
| 1280 | } |
| 1281 | n_sect += @intCast(u16, cmd.Segment.sections.items.len); |
| 1282 | } |
| 1283 | |
| 1284 | const n_strx = try self.makeString(sym_name); |
| 1285 | try locs.entry.value.append(self.allocator, .{ |
| 1286 | .inner = .{ |
| 1287 | .n_strx = n_strx, |
| 1288 | .n_value = n_value, |
| 1289 | .n_type = macho.N_SECT, |
| 1290 | .n_desc = sym.n_desc, |
| 1291 | .n_sect = @intCast(u8, n_sect), |
| 1292 | }, |
| 1293 | .tt = tt, |
| 1294 | .object_id = @intCast(u16, object_id), |
| 1295 | }); |
| 1296 | } |
| 1297 | } |
| 1298 | } |
| 1299 | |
| 1300 | fn doRelocs(self: *Zld) !void { |
| 1301 | for (self.objects.items) |object, object_id| { |
| 1302 | log.debug("\n\n", .{}); |
| 1303 | log.debug("relocating object {s}", .{object.name}); |
| 1304 | |
| 1305 | const seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 1306 | |
| 1307 | for (seg.sections.items) |sect, source_sect_id| { |
| 1308 | const segname = parseName(§.segname); |
| 1309 | const sectname = parseName(§.sectname); |
| 1310 | |
| 1311 | var code = try self.allocator.alloc(u8, sect.size); |
| 1312 | _ = try object.file.preadAll(code, sect.offset); |
| 1313 | defer self.allocator.free(code); |
| 1314 | |
| 1315 | // Parse relocs (if any) |
| 1316 | var raw_relocs = try self.allocator.alloc(u8, @sizeOf(macho.relocation_info) * sect.nreloc); |
| 1317 | defer self.allocator.free(raw_relocs); |
| 1318 | _ = try object.file.preadAll(raw_relocs, sect.reloff); |
| 1319 | const relocs = mem.bytesAsSlice(macho.relocation_info, raw_relocs); |
| 1320 | |
| 1321 | // Get mapping |
| 1322 | const target_mapping = self.mappings.get(.{ |
| 1323 | .object_id = @intCast(u16, object_id), |
| 1324 | .source_sect_id = @intCast(u16, source_sect_id), |
| 1325 | }) orelse { |
| 1326 | log.debug("no mapping for {s},{s}; skipping", .{ segname, sectname }); |
| 1327 | continue; |
| 1328 | }; |
| 1329 | const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment; |
| 1330 | const target_sect = target_seg.sections.items[target_mapping.target_sect_id]; |
| 1331 | const target_sect_addr = target_sect.addr + target_mapping.offset; |
| 1332 | const target_sect_off = target_sect.offset + target_mapping.offset; |
| 1333 | |
| 1334 | var addend: ?u64 = null; |
| 1335 | var sub: ?i64 = null; |
| 1336 | |
| 1337 | for (relocs) |rel| { |
| 1338 | const off = @intCast(u32, rel.r_address); |
| 1339 | const this_addr = target_sect_addr + off; |
| 1340 | |
| 1341 | switch (self.arch.?) { |
| 1342 | .aarch64 => { |
| 1343 | const rel_type = @intToEnum(macho.reloc_type_arm64, rel.r_type); |
| 1344 | log.debug("{s}", .{rel_type}); |
| 1345 | log.debug(" | source address 0x{x}", .{this_addr}); |
| 1346 | log.debug(" | offset 0x{x}", .{off}); |
| 1347 | |
| 1348 | if (rel_type == .ARM64_RELOC_ADDEND) { |
| 1349 | addend = rel.r_symbolnum; |
| 1350 | log.debug(" | calculated addend = 0x{x}", .{addend}); |
| 1351 | // TODO followed by either PAGE21 or PAGEOFF12 only. |
| 1352 | continue; |
| 1353 | } |
| 1354 | }, |
| 1355 | .x86_64 => { |
| 1356 | const rel_type = @intToEnum(macho.reloc_type_x86_64, rel.r_type); |
| 1357 | log.debug("{s}", .{rel_type}); |
| 1358 | log.debug(" | source address 0x{x}", .{this_addr}); |
| 1359 | log.debug(" | offset 0x{x}", .{off}); |
| 1360 | }, |
| 1361 | else => {}, |
| 1362 | } |
| 1363 | |
| 1364 | const target_addr = try self.relocTargetAddr(@intCast(u16, object_id), rel); |
| 1365 | log.debug(" | target address 0x{x}", .{target_addr}); |
| 1366 | if (rel.r_extern == 1) { |
| 1367 | const target_symname = object.getString(object.symtab.items[rel.r_symbolnum].n_strx); |
| 1368 | log.debug(" | target symbol '{s}'", .{target_symname}); |
| 1369 | } else { |
| 1370 | const target_sectname = seg.sections.items[rel.r_symbolnum - 1].sectname; |
| 1371 | log.debug(" | target section '{s}'", .{parseName(&target_sectname)}); |
| 1372 | } |
| 1373 | |
| 1374 | switch (self.arch.?) { |
| 1375 | .x86_64 => { |
| 1376 | const rel_type = @intToEnum(macho.reloc_type_x86_64, rel.r_type); |
| 1377 | |
| 1378 | switch (rel_type) { |
| 1379 | .X86_64_RELOC_BRANCH => { |
| 1380 | assert(rel.r_length == 2); |
| 1381 | const inst = code[off..][0..4]; |
| 1382 | const displacement = @bitCast(u32, @intCast(i32, @intCast(i64, target_addr) - @intCast(i64, this_addr) - 4)); |
| 1383 | mem.writeIntLittle(u32, inst, displacement); |
| 1384 | }, |
| 1385 | .X86_64_RELOC_GOT_LOAD => { |
| 1386 | assert(rel.r_length == 2); |
| 1387 | const inst = code[off..][0..4]; |
| 1388 | const displacement = @bitCast(u32, @intCast(i32, @intCast(i64, target_addr) - @intCast(i64, this_addr) - 4)); |
| 1389 | |
| 1390 | blk: { |
| 1391 | const data_const_seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 1392 | const got = data_const_seg.sections.items[self.got_section_index.?]; |
| 1393 | if (got.addr <= target_addr and target_addr < got.addr + got.size) break :blk; |
| 1394 | log.debug(" | rewriting to leaq", .{}); |
| 1395 | code[off - 2] = 0x8d; |
| 1396 | } |
| 1397 | |
| 1398 | mem.writeIntLittle(u32, inst, displacement); |
| 1399 | }, |
| 1400 | .X86_64_RELOC_GOT => { |
| 1401 | assert(rel.r_length == 2); |
| 1402 | // TODO Instead of referring to the target symbol directly, we refer to it |
| 1403 | // indirectly via GOT. Getting actual target address should be done in the |
| 1404 | // helper relocTargetAddr function rather than here. |
| 1405 | const sym = object.symtab.items[rel.r_symbolnum]; |
| 1406 | const sym_name = try self.allocator.dupe(u8, object.getString(sym.n_strx)); |
| 1407 | const res = try self.nonlazy_pointers.getOrPut(self.allocator, sym_name); |
| 1408 | defer if (res.found_existing) self.allocator.free(sym_name); |
| 1409 | |
| 1410 | const data_const_seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 1411 | const got = data_const_seg.sections.items[self.got_section_index.?]; |
| 1412 | |
| 1413 | if (!res.found_existing) { |
| 1414 | const index = @intCast(u32, self.nonlazy_pointers.items().len) - 1; |
| 1415 | assert(index < max_local_got_indirections); // TODO This is just a temp solution. |
| 1416 | res.entry.value = .{ |
| 1417 | .index = index, |
| 1418 | .target_addr = target_addr, |
| 1419 | }; |
| 1420 | var buf: [@sizeOf(u64)]u8 = undefined; |
| 1421 | mem.writeIntLittle(u64, &buf, target_addr); |
| 1422 | const got_offset = got.offset + (index + self.nonlazy_imports.items().len) * @sizeOf(u64); |
| 1423 | |
| 1424 | log.debug(" | GOT off 0x{x}", .{got.offset}); |
| 1425 | log.debug(" | writing GOT entry 0x{x} at 0x{x}", .{ target_addr, got_offset }); |
| 1426 | |
| 1427 | try self.file.?.pwriteAll(&buf, got_offset); |
| 1428 | } |
| 1429 | |
| 1430 | const index = res.entry.value.index + self.nonlazy_imports.items().len; |
| 1431 | const actual_target_addr = got.addr + index * @sizeOf(u64); |
| 1432 | |
| 1433 | log.debug(" | GOT addr 0x{x}", .{got.addr}); |
| 1434 | log.debug(" | actual target address in GOT 0x{x}", .{actual_target_addr}); |
| 1435 | |
| 1436 | const inst = code[off..][0..4]; |
| 1437 | const displacement = @bitCast(u32, @intCast(i32, @intCast(i64, actual_target_addr) - @intCast(i64, this_addr) - 4)); |
| 1438 | mem.writeIntLittle(u32, inst, displacement); |
| 1439 | }, |
| 1440 | .X86_64_RELOC_TLV => { |
| 1441 | assert(rel.r_length == 2); |
| 1442 | // We need to rewrite the opcode from movq to leaq. |
| 1443 | code[off - 2] = 0x8d; |
| 1444 | // Add displacement. |
| 1445 | const inst = code[off..][0..4]; |
| 1446 | const displacement = @bitCast(u32, @intCast(i32, @intCast(i64, target_addr) - @intCast(i64, this_addr) - 4)); |
| 1447 | mem.writeIntLittle(u32, inst, displacement); |
| 1448 | }, |
| 1449 | .X86_64_RELOC_SIGNED, |
| 1450 | .X86_64_RELOC_SIGNED_1, |
| 1451 | .X86_64_RELOC_SIGNED_2, |
| 1452 | .X86_64_RELOC_SIGNED_4, |
| 1453 | => { |
| 1454 | assert(rel.r_length == 2); |
| 1455 | const inst = code[off..][0..4]; |
| 1456 | const offset = @intCast(i64, mem.readIntLittle(i32, inst)); |
| 1457 | log.debug(" | calculated addend 0x{x}", .{offset}); |
| 1458 | const actual_target_addr = blk: { |
| 1459 | if (rel.r_extern == 1) { |
| 1460 | break :blk @intCast(i64, target_addr) + offset; |
| 1461 | } else { |
| 1462 | const correction: i4 = switch (rel_type) { |
| 1463 | .X86_64_RELOC_SIGNED => 0, |
| 1464 | .X86_64_RELOC_SIGNED_1 => 1, |
| 1465 | .X86_64_RELOC_SIGNED_2 => 2, |
| 1466 | .X86_64_RELOC_SIGNED_4 => 4, |
| 1467 | else => unreachable, |
| 1468 | }; |
| 1469 | log.debug(" | calculated correction 0x{x}", .{correction}); |
| 1470 | |
| 1471 | // The value encoded in the instruction is a displacement - 4 - correction. |
| 1472 | // To obtain the adjusted target address in the final binary, we need |
| 1473 | // calculate the original target address within the object file, establish |
| 1474 | // what the offset from the original target section was, and apply this |
| 1475 | // offset to the resultant target section with this relocated binary. |
| 1476 | const orig_sect_id = @intCast(u16, rel.r_symbolnum - 1); |
| 1477 | const target_map = self.mappings.get(.{ |
| 1478 | .object_id = @intCast(u16, object_id), |
| 1479 | .source_sect_id = orig_sect_id, |
| 1480 | }) orelse unreachable; |
| 1481 | const orig_seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 1482 | const orig_sect = orig_seg.sections.items[orig_sect_id]; |
| 1483 | const orig_offset = off + offset + 4 + correction - @intCast(i64, orig_sect.addr); |
| 1484 | log.debug(" | original offset 0x{x}", .{orig_offset}); |
| 1485 | const adjusted = @intCast(i64, target_addr) + orig_offset; |
| 1486 | log.debug(" | adjusted target address 0x{x}", .{adjusted}); |
| 1487 | break :blk adjusted - correction; |
| 1488 | } |
| 1489 | }; |
| 1490 | const result = actual_target_addr - @intCast(i64, this_addr) - 4; |
| 1491 | const displacement = @bitCast(u32, @intCast(i32, result)); |
| 1492 | mem.writeIntLittle(u32, inst, displacement); |
| 1493 | }, |
| 1494 | .X86_64_RELOC_SUBTRACTOR => { |
| 1495 | sub = @intCast(i64, target_addr); |
| 1496 | }, |
| 1497 | .X86_64_RELOC_UNSIGNED => { |
| 1498 | switch (rel.r_length) { |
| 1499 | 3 => { |
| 1500 | const inst = code[off..][0..8]; |
| 1501 | const offset = mem.readIntLittle(i64, inst); |
| 1502 | |
| 1503 | const result = outer: { |
| 1504 | if (rel.r_extern == 1) { |
| 1505 | log.debug(" | calculated addend 0x{x}", .{offset}); |
| 1506 | if (sub) |s| { |
| 1507 | break :outer @intCast(i64, target_addr) - s + offset; |
| 1508 | } else { |
| 1509 | break :outer @intCast(i64, target_addr) + offset; |
| 1510 | } |
| 1511 | } else { |
| 1512 | // The value encoded in the instruction is an absolute offset |
| 1513 | // from the start of MachO header to the target address in the |
| 1514 | // object file. To extract the address, we calculate the offset from |
| 1515 | // the beginning of the source section to the address, and apply it to |
| 1516 | // the target address value. |
| 1517 | const orig_sect_id = @intCast(u16, rel.r_symbolnum - 1); |
| 1518 | const target_map = self.mappings.get(.{ |
| 1519 | .object_id = @intCast(u16, object_id), |
| 1520 | .source_sect_id = orig_sect_id, |
| 1521 | }) orelse unreachable; |
| 1522 | const orig_seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 1523 | const orig_sect = orig_seg.sections.items[orig_sect_id]; |
| 1524 | const orig_offset = offset - @intCast(i64, orig_sect.addr); |
| 1525 | const actual_target_addr = inner: { |
| 1526 | if (sub) |s| { |
| 1527 | break :inner @intCast(i64, target_addr) - s + orig_offset; |
| 1528 | } else { |
| 1529 | break :inner @intCast(i64, target_addr) + orig_offset; |
| 1530 | } |
| 1531 | }; |
| 1532 | log.debug(" | adjusted target address 0x{x}", .{actual_target_addr}); |
| 1533 | break :outer actual_target_addr; |
| 1534 | } |
| 1535 | }; |
| 1536 | mem.writeIntLittle(u64, inst, @bitCast(u64, result)); |
| 1537 | sub = null; |
| 1538 | |
| 1539 | rebases: { |
| 1540 | var hit: bool = false; |
| 1541 | if (target_mapping.target_seg_id == self.data_segment_cmd_index.?) { |
| 1542 | if (self.data_section_index) |index| { |
| 1543 | if (index == target_mapping.target_sect_id) hit = true; |
| 1544 | } |
| 1545 | } |
| 1546 | if (target_mapping.target_seg_id == self.data_const_segment_cmd_index.?) { |
| 1547 | if (self.data_const_section_index) |index| { |
| 1548 | if (index == target_mapping.target_sect_id) hit = true; |
| 1549 | } |
| 1550 | } |
| 1551 | |
| 1552 | if (!hit) break :rebases; |
| 1553 | |
| 1554 | try self.local_rebases.append(self.allocator, .{ |
| 1555 | .offset = this_addr - target_seg.inner.vmaddr, |
| 1556 | .segment_id = target_mapping.target_seg_id, |
| 1557 | }); |
| 1558 | } |
| 1559 | // TLV is handled via a separate offset mechanism. |
| 1560 | // Calculate the offset to the initializer. |
| 1561 | if (target_sect.flags == macho.S_THREAD_LOCAL_VARIABLES) tlv: { |
| 1562 | assert(rel.r_extern == 1); |
| 1563 | const sym = object.symtab.items[rel.r_symbolnum]; |
| 1564 | if (isImport(&sym)) break :tlv; |
| 1565 | |
| 1566 | const base_addr = blk: { |
| 1567 | if (self.tlv_data_section_index) |index| { |
| 1568 | const tlv_data = target_seg.sections.items[index]; |
| 1569 | break :blk tlv_data.addr; |
| 1570 | } else { |
| 1571 | const tlv_bss = target_seg.sections.items[self.tlv_bss_section_index.?]; |
| 1572 | break :blk tlv_bss.addr; |
| 1573 | } |
| 1574 | }; |
| 1575 | // Since we require TLV data to always preceed TLV bss section, we calculate |
| 1576 | // offsets wrt to the former if it is defined; otherwise, wrt to the latter. |
| 1577 | try self.threadlocal_offsets.append(self.allocator, target_addr - base_addr); |
| 1578 | } |
| 1579 | }, |
| 1580 | 2 => { |
| 1581 | const inst = code[off..][0..4]; |
| 1582 | const offset = mem.readIntLittle(i32, inst); |
| 1583 | log.debug(" | calculated addend 0x{x}", .{offset}); |
| 1584 | const result = if (sub) |s| |
| 1585 | @intCast(i64, target_addr) - s + offset |
| 1586 | else |
| 1587 | @intCast(i64, target_addr) + offset; |
| 1588 | mem.writeIntLittle(u32, inst, @truncate(u32, @bitCast(u64, result))); |
| 1589 | sub = null; |
| 1590 | }, |
| 1591 | else => |len| { |
| 1592 | log.err("unexpected relocation length 0x{x}", .{len}); |
| 1593 | return error.UnexpectedRelocationLength; |
| 1594 | }, |
| 1595 | } |
| 1596 | }, |
| 1597 | } |
| 1598 | }, |
| 1599 | .aarch64 => { |
| 1600 | const rel_type = @intToEnum(macho.reloc_type_arm64, rel.r_type); |
| 1601 | |
| 1602 | switch (rel_type) { |
| 1603 | .ARM64_RELOC_BRANCH26 => { |
| 1604 | assert(rel.r_length == 2); |
| 1605 | const inst = code[off..][0..4]; |
| 1606 | const displacement = @intCast( |
| 1607 | i28, |
| 1608 | @intCast(i64, target_addr) - @intCast(i64, this_addr), |
| 1609 | ); |
| 1610 | var parsed = mem.bytesAsValue( |
| 1611 | meta.TagPayload( |
| 1612 | aarch64.Instruction, |
| 1613 | aarch64.Instruction.UnconditionalBranchImmediate, |
| 1614 | ), |
| 1615 | inst, |
| 1616 | ); |
| 1617 | parsed.imm26 = @truncate(u26, @bitCast(u28, displacement) >> 2); |
| 1618 | }, |
| 1619 | .ARM64_RELOC_PAGE21, |
| 1620 | .ARM64_RELOC_GOT_LOAD_PAGE21, |
| 1621 | .ARM64_RELOC_TLVP_LOAD_PAGE21, |
| 1622 | => { |
| 1623 | assert(rel.r_length == 2); |
| 1624 | const inst = code[off..][0..4]; |
| 1625 | const ta = if (addend) |a| target_addr + a else target_addr; |
| 1626 | const this_page = @intCast(i32, this_addr >> 12); |
| 1627 | const target_page = @intCast(i32, ta >> 12); |
| 1628 | const pages = @bitCast(u21, @intCast(i21, target_page - this_page)); |
| 1629 | log.debug(" | moving by {} pages", .{pages}); |
| 1630 | var parsed = mem.bytesAsValue( |
| 1631 | meta.TagPayload( |
| 1632 | aarch64.Instruction, |
| 1633 | aarch64.Instruction.PCRelativeAddress, |
| 1634 | ), |
| 1635 | inst, |
| 1636 | ); |
| 1637 | parsed.immhi = @truncate(u19, pages >> 2); |
| 1638 | parsed.immlo = @truncate(u2, pages); |
| 1639 | addend = null; |
| 1640 | }, |
| 1641 | .ARM64_RELOC_PAGEOFF12, |
| 1642 | .ARM64_RELOC_GOT_LOAD_PAGEOFF12, |
| 1643 | => { |
| 1644 | const inst = code[off..][0..4]; |
| 1645 | if (aarch64IsArithmetic(inst)) { |
| 1646 | log.debug(" | detected ADD opcode", .{}); |
| 1647 | // add |
| 1648 | var parsed = mem.bytesAsValue( |
| 1649 | meta.TagPayload( |
| 1650 | aarch64.Instruction, |
| 1651 | aarch64.Instruction.AddSubtractImmediate, |
| 1652 | ), |
| 1653 | inst, |
| 1654 | ); |
| 1655 | const ta = if (addend) |a| target_addr + a else target_addr; |
| 1656 | const narrowed = @truncate(u12, ta); |
| 1657 | parsed.imm12 = narrowed; |
| 1658 | } else { |
| 1659 | log.debug(" | detected LDR/STR opcode", .{}); |
| 1660 | // ldr/str |
| 1661 | var parsed = mem.bytesAsValue( |
| 1662 | meta.TagPayload( |
| 1663 | aarch64.Instruction, |
| 1664 | aarch64.Instruction.LoadStoreRegister, |
| 1665 | ), |
| 1666 | inst, |
| 1667 | ); |
| 1668 | |
| 1669 | const ta = if (addend) |a| target_addr + a else target_addr; |
| 1670 | const narrowed = @truncate(u12, ta); |
| 1671 | log.debug(" | narrowed 0x{x}", .{narrowed}); |
| 1672 | log.debug(" | parsed.size 0x{x}", .{parsed.size}); |
| 1673 | |
| 1674 | if (rel_type == .ARM64_RELOC_GOT_LOAD_PAGEOFF12) blk: { |
| 1675 | const data_const_seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 1676 | const got = data_const_seg.sections.items[self.got_section_index.?]; |
| 1677 | if (got.addr <= target_addr and target_addr < got.addr + got.size) break :blk; |
| 1678 | |
| 1679 | log.debug(" | rewriting to add", .{}); |
| 1680 | mem.writeIntLittle(u32, inst, aarch64.Instruction.add( |
| 1681 | @intToEnum(aarch64.Register, parsed.rt), |
| 1682 | @intToEnum(aarch64.Register, parsed.rn), |
| 1683 | narrowed, |
| 1684 | false, |
| 1685 | ).toU32()); |
| 1686 | addend = null; |
| 1687 | continue; |
| 1688 | } |
| 1689 | |
| 1690 | const offset: u12 = blk: { |
| 1691 | if (parsed.size == 0) { |
| 1692 | if (parsed.v == 1) { |
| 1693 | // 128-bit SIMD is scaled by 16. |
| 1694 | break :blk try math.divExact(u12, narrowed, 16); |
| 1695 | } |
| 1696 | // Otherwise, 8-bit SIMD or ldrb. |
| 1697 | break :blk narrowed; |
| 1698 | } else { |
| 1699 | const denom: u4 = try math.powi(u4, 2, parsed.size); |
| 1700 | break :blk try math.divExact(u12, narrowed, denom); |
| 1701 | } |
| 1702 | }; |
| 1703 | parsed.offset = offset; |
| 1704 | } |
| 1705 | addend = null; |
| 1706 | }, |
| 1707 | .ARM64_RELOC_TLVP_LOAD_PAGEOFF12 => { |
| 1708 | const RegInfo = struct { |
| 1709 | rd: u5, |
| 1710 | rn: u5, |
| 1711 | size: u1, |
| 1712 | }; |
| 1713 | const inst = code[off..][0..4]; |
| 1714 | const parsed: RegInfo = blk: { |
| 1715 | if (aarch64IsArithmetic(inst)) { |
| 1716 | const curr = mem.bytesAsValue( |
| 1717 | meta.TagPayload( |
| 1718 | aarch64.Instruction, |
| 1719 | aarch64.Instruction.AddSubtractImmediate, |
| 1720 | ), |
| 1721 | inst, |
| 1722 | ); |
| 1723 | break :blk .{ .rd = curr.rd, .rn = curr.rn, .size = curr.sf }; |
| 1724 | } else { |
| 1725 | const curr = mem.bytesAsValue( |
| 1726 | meta.TagPayload( |
| 1727 | aarch64.Instruction, |
| 1728 | aarch64.Instruction.LoadStoreRegister, |
| 1729 | ), |
| 1730 | inst, |
| 1731 | ); |
| 1732 | break :blk .{ .rd = curr.rt, .rn = curr.rn, .size = @truncate(u1, curr.size) }; |
| 1733 | } |
| 1734 | }; |
| 1735 | const ta = if (addend) |a| target_addr + a else target_addr; |
| 1736 | const narrowed = @truncate(u12, ta); |
| 1737 | log.debug(" | rewriting TLV access to ADD opcode", .{}); |
| 1738 | // For TLV, we always generate an add instruction. |
| 1739 | mem.writeIntLittle(u32, inst, aarch64.Instruction.add( |
| 1740 | @intToEnum(aarch64.Register, parsed.rd), |
| 1741 | @intToEnum(aarch64.Register, parsed.rn), |
| 1742 | narrowed, |
| 1743 | false, |
| 1744 | ).toU32()); |
| 1745 | }, |
| 1746 | .ARM64_RELOC_SUBTRACTOR => { |
| 1747 | sub = @intCast(i64, target_addr); |
| 1748 | }, |
| 1749 | .ARM64_RELOC_UNSIGNED => { |
| 1750 | switch (rel.r_length) { |
| 1751 | 3 => { |
| 1752 | const inst = code[off..][0..8]; |
| 1753 | const offset = mem.readIntLittle(i64, inst); |
| 1754 | log.debug(" | calculated addend 0x{x}", .{offset}); |
| 1755 | const result = if (sub) |s| |
| 1756 | @intCast(i64, target_addr) - s + offset |
| 1757 | else |
| 1758 | @intCast(i64, target_addr) + offset; |
| 1759 | mem.writeIntLittle(u64, inst, @bitCast(u64, result)); |
| 1760 | sub = null; |
| 1761 | |
| 1762 | rebases: { |
| 1763 | var hit: bool = false; |
| 1764 | if (target_mapping.target_seg_id == self.data_segment_cmd_index.?) { |
| 1765 | if (self.data_section_index) |index| { |
| 1766 | if (index == target_mapping.target_sect_id) hit = true; |
| 1767 | } |
| 1768 | } |
| 1769 | if (target_mapping.target_seg_id == self.data_const_segment_cmd_index.?) { |
| 1770 | if (self.data_const_section_index) |index| { |
| 1771 | if (index == target_mapping.target_sect_id) hit = true; |
| 1772 | } |
| 1773 | } |
| 1774 | |
| 1775 | if (!hit) break :rebases; |
| 1776 | |
| 1777 | try self.local_rebases.append(self.allocator, .{ |
| 1778 | .offset = this_addr - target_seg.inner.vmaddr, |
| 1779 | .segment_id = target_mapping.target_seg_id, |
| 1780 | }); |
| 1781 | } |
| 1782 | // TLV is handled via a separate offset mechanism. |
| 1783 | // Calculate the offset to the initializer. |
| 1784 | if (target_sect.flags == macho.S_THREAD_LOCAL_VARIABLES) tlv: { |
| 1785 | assert(rel.r_extern == 1); |
| 1786 | const sym = object.symtab.items[rel.r_symbolnum]; |
| 1787 | if (isImport(&sym)) break :tlv; |
| 1788 | |
| 1789 | const base_addr = blk: { |
| 1790 | if (self.tlv_data_section_index) |index| { |
| 1791 | const tlv_data = target_seg.sections.items[index]; |
| 1792 | break :blk tlv_data.addr; |
| 1793 | } else { |
| 1794 | const tlv_bss = target_seg.sections.items[self.tlv_bss_section_index.?]; |
| 1795 | break :blk tlv_bss.addr; |
| 1796 | } |
| 1797 | }; |
| 1798 | // Since we require TLV data to always preceed TLV bss section, we calculate |
| 1799 | // offsets wrt to the former if it is defined; otherwise, wrt to the latter. |
| 1800 | try self.threadlocal_offsets.append(self.allocator, target_addr - base_addr); |
| 1801 | } |
| 1802 | }, |
| 1803 | 2 => { |
| 1804 | const inst = code[off..][0..4]; |
| 1805 | const offset = mem.readIntLittle(i32, inst); |
| 1806 | log.debug(" | calculated addend 0x{x}", .{offset}); |
| 1807 | const result = if (sub) |s| |
| 1808 | @intCast(i64, target_addr) - s + offset |
| 1809 | else |
| 1810 | @intCast(i64, target_addr) + offset; |
| 1811 | mem.writeIntLittle(u32, inst, @truncate(u32, @bitCast(u64, result))); |
| 1812 | sub = null; |
| 1813 | }, |
| 1814 | else => |len| { |
| 1815 | log.err("unexpected relocation length 0x{x}", .{len}); |
| 1816 | return error.UnexpectedRelocationLength; |
| 1817 | }, |
| 1818 | } |
| 1819 | }, |
| 1820 | .ARM64_RELOC_POINTER_TO_GOT => return error.TODOArm64RelocPointerToGot, |
| 1821 | else => unreachable, |
| 1822 | } |
| 1823 | }, |
| 1824 | else => unreachable, |
| 1825 | } |
| 1826 | } |
| 1827 | |
| 1828 | log.debug("writing contents of '{s},{s}' section from '{s}' from 0x{x} to 0x{x}", .{ |
| 1829 | segname, |
| 1830 | sectname, |
| 1831 | object.name, |
| 1832 | target_sect_off, |
| 1833 | target_sect_off + code.len, |
| 1834 | }); |
| 1835 | |
| 1836 | if (target_sect.flags == macho.S_ZEROFILL or |
| 1837 | target_sect.flags == macho.S_THREAD_LOCAL_ZEROFILL or |
| 1838 | target_sect.flags == macho.S_THREAD_LOCAL_VARIABLES) |
| 1839 | { |
| 1840 | log.debug("zeroing out '{s},{s}' from 0x{x} to 0x{x}", .{ |
| 1841 | parseName(&target_sect.segname), |
| 1842 | parseName(&target_sect.sectname), |
| 1843 | target_sect_off, |
| 1844 | target_sect_off + code.len, |
| 1845 | }); |
| 1846 | // Zero-out the space |
| 1847 | var zeroes = try self.allocator.alloc(u8, code.len); |
| 1848 | defer self.allocator.free(zeroes); |
| 1849 | mem.set(u8, zeroes, 0); |
| 1850 | try self.file.?.pwriteAll(zeroes, target_sect_off); |
| 1851 | } else { |
| 1852 | try self.file.?.pwriteAll(code, target_sect_off); |
| 1853 | } |
| 1854 | } |
| 1855 | } |
| 1856 | } |
| 1857 | |
| 1858 | fn relocTargetAddr(self: *Zld, object_id: u16, rel: macho.relocation_info) !u64 { |
| 1859 | const object = self.objects.items[object_id]; |
| 1860 | const seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 1861 | const target_addr = blk: { |
| 1862 | if (rel.r_extern == 1) { |
| 1863 | const sym = object.symtab.items[rel.r_symbolnum]; |
| 1864 | if (isLocal(&sym) or isExport(&sym)) { |
| 1865 | // Relocate using section offsets only. |
| 1866 | const target_mapping = self.mappings.get(.{ |
| 1867 | .object_id = object_id, |
| 1868 | .source_sect_id = sym.n_sect - 1, |
| 1869 | }) orelse unreachable; |
| 1870 | const source_sect = seg.sections.items[target_mapping.source_sect_id]; |
| 1871 | const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment; |
| 1872 | const target_sect = target_seg.sections.items[target_mapping.target_sect_id]; |
| 1873 | const target_sect_addr = target_sect.addr + target_mapping.offset; |
| 1874 | log.debug(" | symbol local to object", .{}); |
| 1875 | break :blk target_sect_addr + sym.n_value - source_sect.addr; |
| 1876 | } else if (isImport(&sym)) { |
| 1877 | // Relocate to either the artifact's local symbol, or an import from |
| 1878 | // shared library. |
| 1879 | const sym_name = object.getString(sym.n_strx); |
| 1880 | if (self.locals.get(sym_name)) |locs| { |
| 1881 | var n_value: ?u64 = null; |
| 1882 | for (locs.items) |loc| { |
| 1883 | switch (loc.tt) { |
| 1884 | .Global => { |
| 1885 | n_value = loc.inner.n_value; |
| 1886 | break; |
| 1887 | }, |
| 1888 | .WeakGlobal => { |
| 1889 | n_value = loc.inner.n_value; |
| 1890 | }, |
| 1891 | .Local => {}, |
| 1892 | } |
| 1893 | } |
| 1894 | if (n_value) |v| { |
| 1895 | break :blk v; |
| 1896 | } |
| 1897 | log.err("local symbol export '{s}' not found", .{sym_name}); |
| 1898 | return error.LocalSymbolExportNotFound; |
| 1899 | } else if (self.lazy_imports.get(sym_name)) |ext| { |
| 1900 | const segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 1901 | const stubs = segment.sections.items[self.stubs_section_index.?]; |
| 1902 | break :blk stubs.addr + ext.index * stubs.reserved2; |
| 1903 | } else if (self.nonlazy_imports.get(sym_name)) |ext| { |
| 1904 | const segment = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 1905 | const got = segment.sections.items[self.got_section_index.?]; |
| 1906 | break :blk got.addr + ext.index * @sizeOf(u64); |
| 1907 | } else if (mem.eql(u8, sym_name, "__tlv_bootstrap")) { |
| 1908 | const segment = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 1909 | const tlv = segment.sections.items[self.tlv_section_index.?]; |
| 1910 | break :blk tlv.addr + self.tlv_bootstrap.?.index * @sizeOf(u64); |
| 1911 | } else { |
| 1912 | log.err("failed to resolve symbol '{s}' as a relocation target", .{sym_name}); |
| 1913 | return error.FailedToResolveRelocationTarget; |
| 1914 | } |
| 1915 | } else { |
| 1916 | log.err("unexpected symbol {}, {s}", .{ sym, object.getString(sym.n_strx) }); |
| 1917 | return error.UnexpectedSymbolWhenRelocating; |
| 1918 | } |
| 1919 | } else { |
| 1920 | // TODO I think we need to reparse the relocation_info as scattered_relocation_info |
| 1921 | // here to get the actual section plus offset into that section of the relocated |
| 1922 | // symbol. Unless the fine-grained location is encoded within the cell in the code |
| 1923 | // buffer? |
| 1924 | const target_mapping = self.mappings.get(.{ |
| 1925 | .object_id = object_id, |
| 1926 | .source_sect_id = @intCast(u16, rel.r_symbolnum - 1), |
| 1927 | }) orelse unreachable; |
| 1928 | const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment; |
| 1929 | const target_sect = target_seg.sections.items[target_mapping.target_sect_id]; |
| 1930 | break :blk target_sect.addr + target_mapping.offset; |
| 1931 | } |
| 1932 | }; |
| 1933 | return target_addr; |
| 1934 | } |
| 1935 | |
| 1936 | fn populateMetadata(self: *Zld) !void { |
| 1937 | if (self.pagezero_segment_cmd_index == null) { |
| 1938 | self.pagezero_segment_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 1939 | try self.load_commands.append(self.allocator, .{ |
| 1940 | .Segment = SegmentCommand.empty(.{ |
| 1941 | .cmd = macho.LC_SEGMENT_64, |
| 1942 | .cmdsize = @sizeOf(macho.segment_command_64), |
| 1943 | .segname = makeStaticString("__PAGEZERO"), |
| 1944 | .vmaddr = 0, |
| 1945 | .vmsize = 0x100000000, // size always set to 4GB |
| 1946 | .fileoff = 0, |
| 1947 | .filesize = 0, |
| 1948 | .maxprot = 0, |
| 1949 | .initprot = 0, |
| 1950 | .nsects = 0, |
| 1951 | .flags = 0, |
| 1952 | }), |
| 1953 | }); |
| 1954 | } |
| 1955 | |
| 1956 | if (self.text_segment_cmd_index == null) { |
| 1957 | self.text_segment_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 1958 | try self.load_commands.append(self.allocator, .{ |
| 1959 | .Segment = SegmentCommand.empty(.{ |
| 1960 | .cmd = macho.LC_SEGMENT_64, |
| 1961 | .cmdsize = @sizeOf(macho.segment_command_64), |
| 1962 | .segname = makeStaticString("__TEXT"), |
| 1963 | .vmaddr = 0x100000000, // always starts at 4GB |
| 1964 | .vmsize = 0, |
| 1965 | .fileoff = 0, |
| 1966 | .filesize = 0, |
| 1967 | .maxprot = macho.VM_PROT_READ | macho.VM_PROT_EXECUTE, |
| 1968 | .initprot = macho.VM_PROT_READ | macho.VM_PROT_EXECUTE, |
| 1969 | .nsects = 0, |
| 1970 | .flags = 0, |
| 1971 | }), |
| 1972 | }); |
| 1973 | } |
| 1974 | |
| 1975 | if (self.text_section_index == null) { |
| 1976 | const text_seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 1977 | self.text_section_index = @intCast(u16, text_seg.sections.items.len); |
| 1978 | const alignment: u2 = switch (self.arch.?) { |
| 1979 | .x86_64 => 0, |
| 1980 | .aarch64 => 2, |
| 1981 | else => unreachable, // unhandled architecture type |
| 1982 | }; |
| 1983 | try text_seg.addSection(self.allocator, .{ |
| 1984 | .sectname = makeStaticString("__text"), |
| 1985 | .segname = makeStaticString("__TEXT"), |
| 1986 | .addr = 0, |
| 1987 | .size = 0, |
| 1988 | .offset = 0, |
| 1989 | .@"align" = alignment, |
| 1990 | .reloff = 0, |
| 1991 | .nreloc = 0, |
| 1992 | .flags = macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS, |
| 1993 | .reserved1 = 0, |
| 1994 | .reserved2 = 0, |
| 1995 | .reserved3 = 0, |
| 1996 | }); |
| 1997 | } |
| 1998 | |
| 1999 | if (self.stubs_section_index == null) { |
| 2000 | const text_seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 2001 | self.stubs_section_index = @intCast(u16, text_seg.sections.items.len); |
| 2002 | const alignment: u2 = switch (self.arch.?) { |
| 2003 | .x86_64 => 0, |
| 2004 | .aarch64 => 2, |
| 2005 | else => unreachable, // unhandled architecture type |
| 2006 | }; |
| 2007 | const stub_size: u4 = switch (self.arch.?) { |
| 2008 | .x86_64 => 6, |
| 2009 | .aarch64 => 3 * @sizeOf(u32), |
| 2010 | else => unreachable, // unhandled architecture type |
| 2011 | }; |
| 2012 | try text_seg.addSection(self.allocator, .{ |
| 2013 | .sectname = makeStaticString("__stubs"), |
| 2014 | .segname = makeStaticString("__TEXT"), |
| 2015 | .addr = 0, |
| 2016 | .size = 0, |
| 2017 | .offset = 0, |
| 2018 | .@"align" = alignment, |
| 2019 | .reloff = 0, |
| 2020 | .nreloc = 0, |
| 2021 | .flags = macho.S_SYMBOL_STUBS | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS, |
| 2022 | .reserved1 = 0, |
| 2023 | .reserved2 = stub_size, |
| 2024 | .reserved3 = 0, |
| 2025 | }); |
| 2026 | } |
| 2027 | |
| 2028 | if (self.stub_helper_section_index == null) { |
| 2029 | const text_seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 2030 | self.stub_helper_section_index = @intCast(u16, text_seg.sections.items.len); |
| 2031 | const alignment: u2 = switch (self.arch.?) { |
| 2032 | .x86_64 => 0, |
| 2033 | .aarch64 => 2, |
| 2034 | else => unreachable, // unhandled architecture type |
| 2035 | }; |
| 2036 | const stub_helper_size: u6 = switch (self.arch.?) { |
| 2037 | .x86_64 => 15, |
| 2038 | .aarch64 => 6 * @sizeOf(u32), |
| 2039 | else => unreachable, |
| 2040 | }; |
| 2041 | try text_seg.addSection(self.allocator, .{ |
| 2042 | .sectname = makeStaticString("__stub_helper"), |
| 2043 | .segname = makeStaticString("__TEXT"), |
| 2044 | .addr = 0, |
| 2045 | .size = stub_helper_size, |
| 2046 | .offset = 0, |
| 2047 | .@"align" = alignment, |
| 2048 | .reloff = 0, |
| 2049 | .nreloc = 0, |
| 2050 | .flags = macho.S_REGULAR | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS, |
| 2051 | .reserved1 = 0, |
| 2052 | .reserved2 = 0, |
| 2053 | .reserved3 = 0, |
| 2054 | }); |
| 2055 | } |
| 2056 | |
| 2057 | if (self.data_const_segment_cmd_index == null) { |
| 2058 | self.data_const_segment_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2059 | try self.load_commands.append(self.allocator, .{ |
| 2060 | .Segment = SegmentCommand.empty(.{ |
| 2061 | .cmd = macho.LC_SEGMENT_64, |
| 2062 | .cmdsize = @sizeOf(macho.segment_command_64), |
| 2063 | .segname = makeStaticString("__DATA_CONST"), |
| 2064 | .vmaddr = 0, |
| 2065 | .vmsize = 0, |
| 2066 | .fileoff = 0, |
| 2067 | .filesize = 0, |
| 2068 | .maxprot = macho.VM_PROT_READ | macho.VM_PROT_WRITE, |
| 2069 | .initprot = macho.VM_PROT_READ | macho.VM_PROT_WRITE, |
| 2070 | .nsects = 0, |
| 2071 | .flags = 0, |
| 2072 | }), |
| 2073 | }); |
| 2074 | } |
| 2075 | |
| 2076 | if (self.got_section_index == null) { |
| 2077 | const data_const_seg = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 2078 | self.got_section_index = @intCast(u16, data_const_seg.sections.items.len); |
| 2079 | try data_const_seg.addSection(self.allocator, .{ |
| 2080 | .sectname = makeStaticString("__got"), |
| 2081 | .segname = makeStaticString("__DATA_CONST"), |
| 2082 | .addr = 0, |
| 2083 | .size = 0, |
| 2084 | .offset = 0, |
| 2085 | .@"align" = 3, // 2^3 = @sizeOf(u64) |
| 2086 | .reloff = 0, |
| 2087 | .nreloc = 0, |
| 2088 | .flags = macho.S_NON_LAZY_SYMBOL_POINTERS, |
| 2089 | .reserved1 = 0, |
| 2090 | .reserved2 = 0, |
| 2091 | .reserved3 = 0, |
| 2092 | }); |
| 2093 | } |
| 2094 | |
| 2095 | if (self.data_segment_cmd_index == null) { |
| 2096 | self.data_segment_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2097 | try self.load_commands.append(self.allocator, .{ |
| 2098 | .Segment = SegmentCommand.empty(.{ |
| 2099 | .cmd = macho.LC_SEGMENT_64, |
| 2100 | .cmdsize = @sizeOf(macho.segment_command_64), |
| 2101 | .segname = makeStaticString("__DATA"), |
| 2102 | .vmaddr = 0, |
| 2103 | .vmsize = 0, |
| 2104 | .fileoff = 0, |
| 2105 | .filesize = 0, |
| 2106 | .maxprot = macho.VM_PROT_READ | macho.VM_PROT_WRITE, |
| 2107 | .initprot = macho.VM_PROT_READ | macho.VM_PROT_WRITE, |
| 2108 | .nsects = 0, |
| 2109 | .flags = 0, |
| 2110 | }), |
| 2111 | }); |
| 2112 | } |
| 2113 | |
| 2114 | if (self.la_symbol_ptr_section_index == null) { |
| 2115 | const data_seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2116 | self.la_symbol_ptr_section_index = @intCast(u16, data_seg.sections.items.len); |
| 2117 | try data_seg.addSection(self.allocator, .{ |
| 2118 | .sectname = makeStaticString("__la_symbol_ptr"), |
| 2119 | .segname = makeStaticString("__DATA"), |
| 2120 | .addr = 0, |
| 2121 | .size = 0, |
| 2122 | .offset = 0, |
| 2123 | .@"align" = 3, // 2^3 = @sizeOf(u64) |
| 2124 | .reloff = 0, |
| 2125 | .nreloc = 0, |
| 2126 | .flags = macho.S_LAZY_SYMBOL_POINTERS, |
| 2127 | .reserved1 = 0, |
| 2128 | .reserved2 = 0, |
| 2129 | .reserved3 = 0, |
| 2130 | }); |
| 2131 | } |
| 2132 | |
| 2133 | if (self.data_section_index == null) { |
| 2134 | const data_seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2135 | self.data_section_index = @intCast(u16, data_seg.sections.items.len); |
| 2136 | try data_seg.addSection(self.allocator, .{ |
| 2137 | .sectname = makeStaticString("__data"), |
| 2138 | .segname = makeStaticString("__DATA"), |
| 2139 | .addr = 0, |
| 2140 | .size = 0, |
| 2141 | .offset = 0, |
| 2142 | .@"align" = 3, // 2^3 = @sizeOf(u64) |
| 2143 | .reloff = 0, |
| 2144 | .nreloc = 0, |
| 2145 | .flags = macho.S_REGULAR, |
| 2146 | .reserved1 = 0, |
| 2147 | .reserved2 = 0, |
| 2148 | .reserved3 = 0, |
| 2149 | }); |
| 2150 | } |
| 2151 | |
| 2152 | if (self.linkedit_segment_cmd_index == null) { |
| 2153 | self.linkedit_segment_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2154 | try self.load_commands.append(self.allocator, .{ |
| 2155 | .Segment = SegmentCommand.empty(.{ |
| 2156 | .cmd = macho.LC_SEGMENT_64, |
| 2157 | .cmdsize = @sizeOf(macho.segment_command_64), |
| 2158 | .segname = makeStaticString("__LINKEDIT"), |
| 2159 | .vmaddr = 0, |
| 2160 | .vmsize = 0, |
| 2161 | .fileoff = 0, |
| 2162 | .filesize = 0, |
| 2163 | .maxprot = macho.VM_PROT_READ, |
| 2164 | .initprot = macho.VM_PROT_READ, |
| 2165 | .nsects = 0, |
| 2166 | .flags = 0, |
| 2167 | }), |
| 2168 | }); |
| 2169 | } |
| 2170 | |
| 2171 | if (self.dyld_info_cmd_index == null) { |
| 2172 | self.dyld_info_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2173 | try self.load_commands.append(self.allocator, .{ |
| 2174 | .DyldInfoOnly = .{ |
| 2175 | .cmd = macho.LC_DYLD_INFO_ONLY, |
| 2176 | .cmdsize = @sizeOf(macho.dyld_info_command), |
| 2177 | .rebase_off = 0, |
| 2178 | .rebase_size = 0, |
| 2179 | .bind_off = 0, |
| 2180 | .bind_size = 0, |
| 2181 | .weak_bind_off = 0, |
| 2182 | .weak_bind_size = 0, |
| 2183 | .lazy_bind_off = 0, |
| 2184 | .lazy_bind_size = 0, |
| 2185 | .export_off = 0, |
| 2186 | .export_size = 0, |
| 2187 | }, |
| 2188 | }); |
| 2189 | } |
| 2190 | |
| 2191 | if (self.symtab_cmd_index == null) { |
| 2192 | self.symtab_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2193 | try self.load_commands.append(self.allocator, .{ |
| 2194 | .Symtab = .{ |
| 2195 | .cmd = macho.LC_SYMTAB, |
| 2196 | .cmdsize = @sizeOf(macho.symtab_command), |
| 2197 | .symoff = 0, |
| 2198 | .nsyms = 0, |
| 2199 | .stroff = 0, |
| 2200 | .strsize = 0, |
| 2201 | }, |
| 2202 | }); |
| 2203 | try self.strtab.append(self.allocator, 0); |
| 2204 | } |
| 2205 | |
| 2206 | if (self.dysymtab_cmd_index == null) { |
| 2207 | self.dysymtab_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2208 | try self.load_commands.append(self.allocator, .{ |
| 2209 | .Dysymtab = .{ |
| 2210 | .cmd = macho.LC_DYSYMTAB, |
| 2211 | .cmdsize = @sizeOf(macho.dysymtab_command), |
| 2212 | .ilocalsym = 0, |
| 2213 | .nlocalsym = 0, |
| 2214 | .iextdefsym = 0, |
| 2215 | .nextdefsym = 0, |
| 2216 | .iundefsym = 0, |
| 2217 | .nundefsym = 0, |
| 2218 | .tocoff = 0, |
| 2219 | .ntoc = 0, |
| 2220 | .modtaboff = 0, |
| 2221 | .nmodtab = 0, |
| 2222 | .extrefsymoff = 0, |
| 2223 | .nextrefsyms = 0, |
| 2224 | .indirectsymoff = 0, |
| 2225 | .nindirectsyms = 0, |
| 2226 | .extreloff = 0, |
| 2227 | .nextrel = 0, |
| 2228 | .locreloff = 0, |
| 2229 | .nlocrel = 0, |
| 2230 | }, |
| 2231 | }); |
| 2232 | } |
| 2233 | |
| 2234 | if (self.dylinker_cmd_index == null) { |
| 2235 | self.dylinker_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2236 | const cmdsize = @intCast(u32, mem.alignForwardGeneric( |
| 2237 | u64, |
| 2238 | @sizeOf(macho.dylinker_command) + mem.lenZ(DEFAULT_DYLD_PATH), |
| 2239 | @sizeOf(u64), |
| 2240 | )); |
| 2241 | var dylinker_cmd = emptyGenericCommandWithData(macho.dylinker_command{ |
| 2242 | .cmd = macho.LC_LOAD_DYLINKER, |
| 2243 | .cmdsize = cmdsize, |
| 2244 | .name = @sizeOf(macho.dylinker_command), |
| 2245 | }); |
| 2246 | dylinker_cmd.data = try self.allocator.alloc(u8, cmdsize - dylinker_cmd.inner.name); |
| 2247 | mem.set(u8, dylinker_cmd.data, 0); |
| 2248 | mem.copy(u8, dylinker_cmd.data, mem.spanZ(DEFAULT_DYLD_PATH)); |
| 2249 | try self.load_commands.append(self.allocator, .{ .Dylinker = dylinker_cmd }); |
| 2250 | } |
| 2251 | |
| 2252 | if (self.libsystem_cmd_index == null) { |
| 2253 | self.libsystem_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2254 | const cmdsize = @intCast(u32, mem.alignForwardGeneric( |
| 2255 | u64, |
| 2256 | @sizeOf(macho.dylib_command) + mem.lenZ(LIB_SYSTEM_PATH), |
| 2257 | @sizeOf(u64), |
| 2258 | )); |
| 2259 | // TODO Find a way to work out runtime version from the OS version triple stored in std.Target. |
| 2260 | // In the meantime, we're gonna hardcode to the minimum compatibility version of 0.0.0. |
| 2261 | const min_version = 0x0; |
| 2262 | var dylib_cmd = emptyGenericCommandWithData(macho.dylib_command{ |
| 2263 | .cmd = macho.LC_LOAD_DYLIB, |
| 2264 | .cmdsize = cmdsize, |
| 2265 | .dylib = .{ |
| 2266 | .name = @sizeOf(macho.dylib_command), |
| 2267 | .timestamp = 2, // not sure why not simply 0; this is reverse engineered from Mach-O files |
| 2268 | .current_version = min_version, |
| 2269 | .compatibility_version = min_version, |
| 2270 | }, |
| 2271 | }); |
| 2272 | dylib_cmd.data = try self.allocator.alloc(u8, cmdsize - dylib_cmd.inner.dylib.name); |
| 2273 | mem.set(u8, dylib_cmd.data, 0); |
| 2274 | mem.copy(u8, dylib_cmd.data, mem.spanZ(LIB_SYSTEM_PATH)); |
| 2275 | try self.load_commands.append(self.allocator, .{ .Dylib = dylib_cmd }); |
| 2276 | } |
| 2277 | |
| 2278 | if (self.main_cmd_index == null) { |
| 2279 | self.main_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2280 | try self.load_commands.append(self.allocator, .{ |
| 2281 | .Main = .{ |
| 2282 | .cmd = macho.LC_MAIN, |
| 2283 | .cmdsize = @sizeOf(macho.entry_point_command), |
| 2284 | .entryoff = 0x0, |
| 2285 | .stacksize = 0, |
| 2286 | }, |
| 2287 | }); |
| 2288 | } |
| 2289 | |
| 2290 | if (self.source_version_cmd_index == null) { |
| 2291 | self.source_version_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2292 | try self.load_commands.append(self.allocator, .{ |
| 2293 | .SourceVersion = .{ |
| 2294 | .cmd = macho.LC_SOURCE_VERSION, |
| 2295 | .cmdsize = @sizeOf(macho.source_version_command), |
| 2296 | .version = 0x0, |
| 2297 | }, |
| 2298 | }); |
| 2299 | } |
| 2300 | |
| 2301 | if (self.uuid_cmd_index == null) { |
| 2302 | self.uuid_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2303 | var uuid_cmd: macho.uuid_command = .{ |
| 2304 | .cmd = macho.LC_UUID, |
| 2305 | .cmdsize = @sizeOf(macho.uuid_command), |
| 2306 | .uuid = undefined, |
| 2307 | }; |
| 2308 | std.crypto.random.bytes(&uuid_cmd.uuid); |
| 2309 | try self.load_commands.append(self.allocator, .{ .Uuid = uuid_cmd }); |
| 2310 | } |
| 2311 | |
| 2312 | if (self.code_signature_cmd_index == null and self.arch.? == .aarch64) { |
| 2313 | self.code_signature_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2314 | try self.load_commands.append(self.allocator, .{ |
| 2315 | .LinkeditData = .{ |
| 2316 | .cmd = macho.LC_CODE_SIGNATURE, |
| 2317 | .cmdsize = @sizeOf(macho.linkedit_data_command), |
| 2318 | .dataoff = 0, |
| 2319 | .datasize = 0, |
| 2320 | }, |
| 2321 | }); |
| 2322 | } |
| 2323 | |
| 2324 | if (self.data_in_code_cmd_index == null and self.arch.? == .x86_64) { |
| 2325 | self.data_in_code_cmd_index = @intCast(u16, self.load_commands.items.len); |
| 2326 | try self.load_commands.append(self.allocator, .{ |
| 2327 | .LinkeditData = .{ |
| 2328 | .cmd = macho.LC_DATA_IN_CODE, |
| 2329 | .cmdsize = @sizeOf(macho.linkedit_data_command), |
| 2330 | .dataoff = 0, |
| 2331 | .datasize = 0, |
| 2332 | }, |
| 2333 | }); |
| 2334 | } |
| 2335 | } |
| 2336 | |
| 2337 | fn flush(self: *Zld) !void { |
| 2338 | if (self.bss_section_index) |index| { |
| 2339 | const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2340 | const sect = &seg.sections.items[index]; |
| 2341 | sect.offset = 0; |
| 2342 | } |
| 2343 | |
| 2344 | if (self.tlv_bss_section_index) |index| { |
| 2345 | const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2346 | const sect = &seg.sections.items[index]; |
| 2347 | sect.offset = 0; |
| 2348 | } |
| 2349 | |
| 2350 | if (self.tlv_section_index) |index| { |
| 2351 | const seg = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2352 | const sect = &seg.sections.items[index]; |
| 2353 | |
| 2354 | var buffer = try self.allocator.alloc(u8, sect.size); |
| 2355 | defer self.allocator.free(buffer); |
| 2356 | _ = try self.file.?.preadAll(buffer, sect.offset); |
| 2357 | |
| 2358 | var stream = std.io.fixedBufferStream(buffer); |
| 2359 | var writer = stream.writer(); |
| 2360 | |
| 2361 | const seek_amt = 2 * @sizeOf(u64); |
| 2362 | while (self.threadlocal_offsets.popOrNull()) |offset| { |
| 2363 | try writer.context.seekBy(seek_amt); |
| 2364 | try writer.writeIntLittle(u64, offset); |
| 2365 | } |
| 2366 | |
| 2367 | try self.file.?.pwriteAll(buffer, sect.offset); |
| 2368 | } |
| 2369 | |
| 2370 | try self.setEntryPoint(); |
| 2371 | try self.writeRebaseInfoTable(); |
| 2372 | try self.writeBindInfoTable(); |
| 2373 | try self.writeLazyBindInfoTable(); |
| 2374 | try self.writeExportInfo(); |
| 2375 | if (self.arch.? == .x86_64) { |
| 2376 | try self.writeDataInCode(); |
| 2377 | } |
| 2378 | |
| 2379 | { |
| 2380 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2381 | const symtab = &self.load_commands.items[self.symtab_cmd_index.?].Symtab; |
| 2382 | symtab.symoff = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2383 | } |
| 2384 | |
| 2385 | try self.writeDebugInfo(); |
| 2386 | try self.writeSymbolTable(); |
| 2387 | try self.writeDynamicSymbolTable(); |
| 2388 | try self.writeStringTable(); |
| 2389 | |
| 2390 | { |
| 2391 | // Seal __LINKEDIT size |
| 2392 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2393 | seg.inner.vmsize = mem.alignForwardGeneric(u64, seg.inner.filesize, self.page_size.?); |
| 2394 | } |
| 2395 | |
| 2396 | if (self.arch.? == .aarch64) { |
| 2397 | try self.writeCodeSignaturePadding(); |
| 2398 | } |
| 2399 | |
| 2400 | try self.writeLoadCommands(); |
| 2401 | try self.writeHeader(); |
| 2402 | |
| 2403 | if (self.arch.? == .aarch64) { |
| 2404 | try self.writeCodeSignature(); |
| 2405 | } |
| 2406 | |
| 2407 | if (comptime std.Target.current.isDarwin() and std.Target.current.cpu.arch == .aarch64) { |
| 2408 | try fs.cwd().copyFile(self.out_path.?, fs.cwd(), self.out_path.?, .{}); |
| 2409 | } |
| 2410 | } |
| 2411 | |
| 2412 | fn setEntryPoint(self: *Zld) !void { |
| 2413 | // TODO we should respect the -entry flag passed in by the user to set a custom |
| 2414 | // entrypoint. For now, assume default of `_main`. |
| 2415 | const seg = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 2416 | const text = seg.sections.items[self.text_section_index.?]; |
| 2417 | const entry_syms = self.locals.get("_main") orelse return error.MissingMainEntrypoint; |
| 2418 | |
| 2419 | var entry_sym: ?macho.nlist_64 = null; |
| 2420 | for (entry_syms.items) |es| { |
| 2421 | switch (es.tt) { |
| 2422 | .Global => { |
| 2423 | entry_sym = es.inner; |
| 2424 | break; |
| 2425 | }, |
| 2426 | .WeakGlobal => { |
| 2427 | entry_sym = es.inner; |
| 2428 | }, |
| 2429 | .Local => {}, |
| 2430 | } |
| 2431 | } |
| 2432 | if (entry_sym == null) { |
| 2433 | log.err("no (weak) global definition of _main found", .{}); |
| 2434 | return error.MissingMainEntrypoint; |
| 2435 | } |
| 2436 | |
| 2437 | const name = try self.allocator.dupe(u8, "_main"); |
| 2438 | try self.exports.putNoClobber(self.allocator, name, .{ |
| 2439 | .n_strx = entry_sym.?.n_strx, |
| 2440 | .n_value = entry_sym.?.n_value, |
| 2441 | .n_type = macho.N_SECT | macho.N_EXT, |
| 2442 | .n_desc = entry_sym.?.n_desc, |
| 2443 | .n_sect = entry_sym.?.n_sect, |
| 2444 | }); |
| 2445 | |
| 2446 | const ec = &self.load_commands.items[self.main_cmd_index.?].Main; |
| 2447 | ec.entryoff = @intCast(u32, entry_sym.?.n_value - seg.inner.vmaddr); |
| 2448 | } |
| 2449 | |
| 2450 | fn writeRebaseInfoTable(self: *Zld) !void { |
| 2451 | var pointers = std.ArrayList(Pointer).init(self.allocator); |
| 2452 | defer pointers.deinit(); |
| 2453 | |
| 2454 | try pointers.ensureCapacity(pointers.items.len + self.local_rebases.items.len); |
| 2455 | pointers.appendSliceAssumeCapacity(self.local_rebases.items); |
| 2456 | |
| 2457 | if (self.got_section_index) |idx| { |
| 2458 | // TODO this should be cleaned up! |
| 2459 | try pointers.ensureCapacity(pointers.items.len + self.nonlazy_pointers.items().len); |
| 2460 | const seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 2461 | const sect = seg.sections.items[idx]; |
| 2462 | const base_offset = sect.addr - seg.inner.vmaddr; |
| 2463 | const segment_id = @intCast(u16, self.data_const_segment_cmd_index.?); |
| 2464 | const index_offset = @intCast(u32, self.nonlazy_imports.items().len); |
| 2465 | for (self.nonlazy_pointers.items()) |entry| { |
| 2466 | const index = index_offset + entry.value.index; |
| 2467 | pointers.appendAssumeCapacity(.{ |
| 2468 | .offset = base_offset + index * @sizeOf(u64), |
| 2469 | .segment_id = segment_id, |
| 2470 | }); |
| 2471 | } |
| 2472 | } |
| 2473 | |
| 2474 | if (self.la_symbol_ptr_section_index) |idx| { |
| 2475 | try pointers.ensureCapacity(pointers.items.len + self.lazy_imports.items().len); |
| 2476 | const seg = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2477 | const sect = seg.sections.items[idx]; |
| 2478 | const base_offset = sect.addr - seg.inner.vmaddr; |
| 2479 | const segment_id = @intCast(u16, self.data_segment_cmd_index.?); |
| 2480 | for (self.lazy_imports.items()) |entry| { |
| 2481 | pointers.appendAssumeCapacity(.{ |
| 2482 | .offset = base_offset + entry.value.index * @sizeOf(u64), |
| 2483 | .segment_id = segment_id, |
| 2484 | }); |
| 2485 | } |
| 2486 | } |
| 2487 | |
| 2488 | std.sort.sort(Pointer, pointers.items, {}, pointerCmp); |
| 2489 | |
| 2490 | const size = try rebaseInfoSize(pointers.items); |
| 2491 | var buffer = try self.allocator.alloc(u8, @intCast(usize, size)); |
| 2492 | defer self.allocator.free(buffer); |
| 2493 | |
| 2494 | var stream = std.io.fixedBufferStream(buffer); |
| 2495 | try writeRebaseInfo(pointers.items, stream.writer()); |
| 2496 | |
| 2497 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2498 | const dyld_info = &self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly; |
| 2499 | dyld_info.rebase_off = @intCast(u32, seg.inner.fileoff); |
| 2500 | dyld_info.rebase_size = @intCast(u32, mem.alignForwardGeneric(u64, buffer.len, @sizeOf(u64))); |
| 2501 | seg.inner.filesize += dyld_info.rebase_size; |
| 2502 | |
| 2503 | log.debug("writing rebase info from 0x{x} to 0x{x}", .{ dyld_info.rebase_off, dyld_info.rebase_off + dyld_info.rebase_size }); |
| 2504 | |
| 2505 | try self.file.?.pwriteAll(buffer, dyld_info.rebase_off); |
| 2506 | } |
| 2507 | |
| 2508 | fn writeBindInfoTable(self: *Zld) !void { |
| 2509 | var pointers = std.ArrayList(Pointer).init(self.allocator); |
| 2510 | defer pointers.deinit(); |
| 2511 | |
| 2512 | if (self.got_section_index) |idx| { |
| 2513 | try pointers.ensureCapacity(pointers.items.len + self.nonlazy_imports.items().len); |
| 2514 | const seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 2515 | const sect = seg.sections.items[idx]; |
| 2516 | const base_offset = sect.addr - seg.inner.vmaddr; |
| 2517 | const segment_id = @intCast(u16, self.data_const_segment_cmd_index.?); |
| 2518 | for (self.nonlazy_imports.items()) |entry| { |
| 2519 | pointers.appendAssumeCapacity(.{ |
| 2520 | .offset = base_offset + entry.value.index * @sizeOf(u64), |
| 2521 | .segment_id = segment_id, |
| 2522 | .dylib_ordinal = entry.value.dylib_ordinal, |
| 2523 | .name = entry.key, |
| 2524 | }); |
| 2525 | } |
| 2526 | } |
| 2527 | |
| 2528 | if (self.tlv_section_index) |idx| { |
| 2529 | const seg = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2530 | const sect = seg.sections.items[idx]; |
| 2531 | const base_offset = sect.addr - seg.inner.vmaddr; |
| 2532 | const segment_id = @intCast(u16, self.data_segment_cmd_index.?); |
| 2533 | try pointers.append(.{ |
| 2534 | .offset = base_offset + self.tlv_bootstrap.?.index * @sizeOf(u64), |
| 2535 | .segment_id = segment_id, |
| 2536 | .dylib_ordinal = self.tlv_bootstrap.?.dylib_ordinal, |
| 2537 | .name = "__tlv_bootstrap", |
| 2538 | }); |
| 2539 | } |
| 2540 | |
| 2541 | const size = try bindInfoSize(pointers.items); |
| 2542 | var buffer = try self.allocator.alloc(u8, @intCast(usize, size)); |
| 2543 | defer self.allocator.free(buffer); |
| 2544 | |
| 2545 | var stream = std.io.fixedBufferStream(buffer); |
| 2546 | try writeBindInfo(pointers.items, stream.writer()); |
| 2547 | |
| 2548 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2549 | const dyld_info = &self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly; |
| 2550 | dyld_info.bind_off = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2551 | dyld_info.bind_size = @intCast(u32, mem.alignForwardGeneric(u64, buffer.len, @alignOf(u64))); |
| 2552 | seg.inner.filesize += dyld_info.bind_size; |
| 2553 | |
| 2554 | log.debug("writing binding info from 0x{x} to 0x{x}", .{ dyld_info.bind_off, dyld_info.bind_off + dyld_info.bind_size }); |
| 2555 | |
| 2556 | try self.file.?.pwriteAll(buffer, dyld_info.bind_off); |
| 2557 | } |
| 2558 | |
| 2559 | fn writeLazyBindInfoTable(self: *Zld) !void { |
| 2560 | var pointers = std.ArrayList(Pointer).init(self.allocator); |
| 2561 | defer pointers.deinit(); |
| 2562 | try pointers.ensureCapacity(self.lazy_imports.items().len); |
| 2563 | |
| 2564 | if (self.la_symbol_ptr_section_index) |idx| { |
| 2565 | const seg = self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2566 | const sect = seg.sections.items[idx]; |
| 2567 | const base_offset = sect.addr - seg.inner.vmaddr; |
| 2568 | const segment_id = @intCast(u16, self.data_segment_cmd_index.?); |
| 2569 | for (self.lazy_imports.items()) |entry| { |
| 2570 | pointers.appendAssumeCapacity(.{ |
| 2571 | .offset = base_offset + entry.value.index * @sizeOf(u64), |
| 2572 | .segment_id = segment_id, |
| 2573 | .dylib_ordinal = entry.value.dylib_ordinal, |
| 2574 | .name = entry.key, |
| 2575 | }); |
| 2576 | } |
| 2577 | } |
| 2578 | |
| 2579 | const size = try lazyBindInfoSize(pointers.items); |
| 2580 | var buffer = try self.allocator.alloc(u8, @intCast(usize, size)); |
| 2581 | defer self.allocator.free(buffer); |
| 2582 | |
| 2583 | var stream = std.io.fixedBufferStream(buffer); |
| 2584 | try writeLazyBindInfo(pointers.items, stream.writer()); |
| 2585 | |
| 2586 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2587 | const dyld_info = &self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly; |
| 2588 | dyld_info.lazy_bind_off = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2589 | dyld_info.lazy_bind_size = @intCast(u32, mem.alignForwardGeneric(u64, buffer.len, @alignOf(u64))); |
| 2590 | seg.inner.filesize += dyld_info.lazy_bind_size; |
| 2591 | |
| 2592 | log.debug("writing lazy binding info from 0x{x} to 0x{x}", .{ dyld_info.lazy_bind_off, dyld_info.lazy_bind_off + dyld_info.lazy_bind_size }); |
| 2593 | |
| 2594 | try self.file.?.pwriteAll(buffer, dyld_info.lazy_bind_off); |
| 2595 | try self.populateLazyBindOffsetsInStubHelper(buffer); |
| 2596 | } |
| 2597 | |
| 2598 | fn populateLazyBindOffsetsInStubHelper(self: *Zld, buffer: []const u8) !void { |
| 2599 | var stream = std.io.fixedBufferStream(buffer); |
| 2600 | var reader = stream.reader(); |
| 2601 | var offsets = std.ArrayList(u32).init(self.allocator); |
| 2602 | try offsets.append(0); |
| 2603 | defer offsets.deinit(); |
| 2604 | var valid_block = false; |
| 2605 | |
| 2606 | while (true) { |
| 2607 | const inst = reader.readByte() catch |err| switch (err) { |
| 2608 | error.EndOfStream => break, |
| 2609 | else => return err, |
| 2610 | }; |
| 2611 | const imm: u8 = inst & macho.BIND_IMMEDIATE_MASK; |
| 2612 | const opcode: u8 = inst & macho.BIND_OPCODE_MASK; |
| 2613 | |
| 2614 | switch (opcode) { |
| 2615 | macho.BIND_OPCODE_DO_BIND => { |
| 2616 | valid_block = true; |
| 2617 | }, |
| 2618 | macho.BIND_OPCODE_DONE => { |
| 2619 | if (valid_block) { |
| 2620 | const offset = try stream.getPos(); |
| 2621 | try offsets.append(@intCast(u32, offset)); |
| 2622 | } |
| 2623 | valid_block = false; |
| 2624 | }, |
| 2625 | macho.BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM => { |
| 2626 | var next = try reader.readByte(); |
| 2627 | while (next != @as(u8, 0)) { |
| 2628 | next = try reader.readByte(); |
| 2629 | } |
| 2630 | }, |
| 2631 | macho.BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => { |
| 2632 | _ = try leb.readULEB128(u64, reader); |
| 2633 | }, |
| 2634 | macho.BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB => { |
| 2635 | _ = try leb.readULEB128(u64, reader); |
| 2636 | }, |
| 2637 | macho.BIND_OPCODE_SET_ADDEND_SLEB => { |
| 2638 | _ = try leb.readILEB128(i64, reader); |
| 2639 | }, |
| 2640 | else => {}, |
| 2641 | } |
| 2642 | } |
| 2643 | assert(self.lazy_imports.items().len <= offsets.items.len); |
| 2644 | |
| 2645 | const stub_size: u4 = switch (self.arch.?) { |
| 2646 | .x86_64 => 10, |
| 2647 | .aarch64 => 3 * @sizeOf(u32), |
| 2648 | else => unreachable, |
| 2649 | }; |
| 2650 | const off: u4 = switch (self.arch.?) { |
| 2651 | .x86_64 => 1, |
| 2652 | .aarch64 => 2 * @sizeOf(u32), |
| 2653 | else => unreachable, |
| 2654 | }; |
| 2655 | var buf: [@sizeOf(u32)]u8 = undefined; |
| 2656 | for (self.lazy_imports.items()) |entry| { |
| 2657 | const symbol = entry.value; |
| 2658 | const placeholder_off = self.stub_helper_stubs_start_off.? + symbol.index * stub_size + off; |
| 2659 | mem.writeIntLittle(u32, &buf, offsets.items[symbol.index]); |
| 2660 | try self.file.?.pwriteAll(&buf, placeholder_off); |
| 2661 | } |
| 2662 | } |
| 2663 | |
| 2664 | fn writeExportInfo(self: *Zld) !void { |
| 2665 | var trie = Trie.init(self.allocator); |
| 2666 | defer trie.deinit(); |
| 2667 | |
| 2668 | const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 2669 | for (self.exports.items()) |entry| { |
| 2670 | const name = entry.key; |
| 2671 | const symbol = entry.value; |
| 2672 | // TODO figure out if we should put all exports into the export trie |
| 2673 | assert(symbol.n_value >= text_segment.inner.vmaddr); |
| 2674 | try trie.put(.{ |
| 2675 | .name = name, |
| 2676 | .vmaddr_offset = symbol.n_value - text_segment.inner.vmaddr, |
| 2677 | .export_flags = macho.EXPORT_SYMBOL_FLAGS_KIND_REGULAR, |
| 2678 | }); |
| 2679 | } |
| 2680 | |
| 2681 | try trie.finalize(); |
| 2682 | var buffer = try self.allocator.alloc(u8, @intCast(usize, trie.size)); |
| 2683 | defer self.allocator.free(buffer); |
| 2684 | var stream = std.io.fixedBufferStream(buffer); |
| 2685 | const nwritten = try trie.write(stream.writer()); |
| 2686 | assert(nwritten == trie.size); |
| 2687 | |
| 2688 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2689 | const dyld_info = &self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly; |
| 2690 | dyld_info.export_off = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2691 | dyld_info.export_size = @intCast(u32, mem.alignForwardGeneric(u64, buffer.len, @alignOf(u64))); |
| 2692 | seg.inner.filesize += dyld_info.export_size; |
| 2693 | |
| 2694 | log.debug("writing export info from 0x{x} to 0x{x}", .{ dyld_info.export_off, dyld_info.export_off + dyld_info.export_size }); |
| 2695 | |
| 2696 | try self.file.?.pwriteAll(buffer, dyld_info.export_off); |
| 2697 | } |
| 2698 | |
| 2699 | fn writeDebugInfo(self: *Zld) !void { |
| 2700 | var stabs = std.ArrayList(macho.nlist_64).init(self.allocator); |
| 2701 | defer stabs.deinit(); |
| 2702 | |
| 2703 | for (self.objects.items) |object, object_id| { |
| 2704 | var debug_info = blk: { |
| 2705 | var di = try DebugInfo.parseFromObject(self.allocator, object); |
| 2706 | break :blk di orelse continue; |
| 2707 | }; |
| 2708 | defer debug_info.deinit(self.allocator); |
| 2709 | |
| 2710 | const compile_unit = try debug_info.inner.findCompileUnit(0x0); // We assume there is only one CU. |
| 2711 | const name = try compile_unit.die.getAttrString(&debug_info.inner, dwarf.AT_name); |
| 2712 | const comp_dir = try compile_unit.die.getAttrString(&debug_info.inner, dwarf.AT_comp_dir); |
| 2713 | |
| 2714 | { |
| 2715 | const tu_path = try std.fs.path.join(self.allocator, &[_][]const u8{ comp_dir, name }); |
| 2716 | defer self.allocator.free(tu_path); |
| 2717 | const dirname = std.fs.path.dirname(tu_path) orelse "./"; |
| 2718 | // Current dir |
| 2719 | try stabs.append(.{ |
| 2720 | .n_strx = try self.makeString(tu_path[0 .. dirname.len + 1]), |
| 2721 | .n_type = macho.N_SO, |
| 2722 | .n_sect = 0, |
| 2723 | .n_desc = 0, |
| 2724 | .n_value = 0, |
| 2725 | }); |
| 2726 | // Artifact name |
| 2727 | try stabs.append(.{ |
| 2728 | .n_strx = try self.makeString(tu_path[dirname.len + 1 ..]), |
| 2729 | .n_type = macho.N_SO, |
| 2730 | .n_sect = 0, |
| 2731 | .n_desc = 0, |
| 2732 | .n_value = 0, |
| 2733 | }); |
| 2734 | // Path to object file with debug info |
| 2735 | var buffer: [std.fs.MAX_PATH_BYTES]u8 = undefined; |
| 2736 | const full_path = blk: { |
| 2737 | if (object.ar_name) |prefix| { |
| 2738 | const path = try std.os.realpath(prefix, &buffer); |
| 2739 | break :blk try std.fmt.allocPrint(self.allocator, "{s}({s})", .{ path, object.name }); |
| 2740 | } else { |
| 2741 | const path = try std.os.realpath(object.name, &buffer); |
| 2742 | break :blk try mem.dupe(self.allocator, u8, path); |
| 2743 | } |
| 2744 | }; |
| 2745 | defer self.allocator.free(full_path); |
| 2746 | const stat = try object.file.stat(); |
| 2747 | const mtime = @intCast(u64, @divFloor(stat.mtime, 1_000_000_000)); |
| 2748 | try stabs.append(.{ |
| 2749 | .n_strx = try self.makeString(full_path), |
| 2750 | .n_type = macho.N_OSO, |
| 2751 | .n_sect = 0, |
| 2752 | .n_desc = 1, |
| 2753 | .n_value = mtime, |
| 2754 | }); |
| 2755 | } |
| 2756 | log.debug("analyzing debug info in '{s}'", .{object.name}); |
| 2757 | |
| 2758 | for (object.symtab.items) |source_sym| { |
| 2759 | const symname = object.getString(source_sym.n_strx); |
| 2760 | const source_addr = source_sym.n_value; |
| 2761 | const target_syms = self.locals.get(symname) orelse continue; |
| 2762 | const target_sym: Symbol = blk: { |
| 2763 | for (target_syms.items) |ts| { |
| 2764 | if (ts.object_id == @intCast(u16, object_id)) break :blk ts; |
| 2765 | } else continue; |
| 2766 | }; |
| 2767 | |
| 2768 | const maybe_size = blk: for (debug_info.inner.func_list.items) |func| { |
| 2769 | if (func.pc_range) |range| { |
| 2770 | if (source_addr >= range.start and source_addr < range.end) { |
| 2771 | break :blk range.end - range.start; |
| 2772 | } |
| 2773 | } |
| 2774 | } else null; |
| 2775 | |
| 2776 | if (maybe_size) |size| { |
| 2777 | try stabs.append(.{ |
| 2778 | .n_strx = 0, |
| 2779 | .n_type = macho.N_BNSYM, |
| 2780 | .n_sect = target_sym.inner.n_sect, |
| 2781 | .n_desc = 0, |
| 2782 | .n_value = target_sym.inner.n_value, |
| 2783 | }); |
| 2784 | try stabs.append(.{ |
| 2785 | .n_strx = target_sym.inner.n_strx, |
| 2786 | .n_type = macho.N_FUN, |
| 2787 | .n_sect = target_sym.inner.n_sect, |
| 2788 | .n_desc = 0, |
| 2789 | .n_value = target_sym.inner.n_value, |
| 2790 | }); |
| 2791 | try stabs.append(.{ |
| 2792 | .n_strx = 0, |
| 2793 | .n_type = macho.N_FUN, |
| 2794 | .n_sect = 0, |
| 2795 | .n_desc = 0, |
| 2796 | .n_value = size, |
| 2797 | }); |
| 2798 | try stabs.append(.{ |
| 2799 | .n_strx = 0, |
| 2800 | .n_type = macho.N_ENSYM, |
| 2801 | .n_sect = target_sym.inner.n_sect, |
| 2802 | .n_desc = 0, |
| 2803 | .n_value = size, |
| 2804 | }); |
| 2805 | } else { |
| 2806 | // TODO need a way to differentiate symbols: global, static, local, etc. |
| 2807 | try stabs.append(.{ |
| 2808 | .n_strx = target_sym.inner.n_strx, |
| 2809 | .n_type = macho.N_STSYM, |
| 2810 | .n_sect = target_sym.inner.n_sect, |
| 2811 | .n_desc = 0, |
| 2812 | .n_value = target_sym.inner.n_value, |
| 2813 | }); |
| 2814 | } |
| 2815 | } |
| 2816 | |
| 2817 | // Close the source file! |
| 2818 | try stabs.append(.{ |
| 2819 | .n_strx = 0, |
| 2820 | .n_type = macho.N_SO, |
| 2821 | .n_sect = 0, |
| 2822 | .n_desc = 0, |
| 2823 | .n_value = 0, |
| 2824 | }); |
| 2825 | } |
| 2826 | |
| 2827 | if (stabs.items.len == 0) return; |
| 2828 | |
| 2829 | // Write stabs into the symbol table |
| 2830 | const linkedit = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2831 | const symtab = &self.load_commands.items[self.symtab_cmd_index.?].Symtab; |
| 2832 | |
| 2833 | symtab.nsyms = @intCast(u32, stabs.items.len); |
| 2834 | |
| 2835 | const stabs_off = symtab.symoff; |
| 2836 | const stabs_size = symtab.nsyms * @sizeOf(macho.nlist_64); |
| 2837 | log.debug("writing symbol stabs from 0x{x} to 0x{x}", .{ stabs_off, stabs_size + stabs_off }); |
| 2838 | try self.file.?.pwriteAll(mem.sliceAsBytes(stabs.items), stabs_off); |
| 2839 | |
| 2840 | linkedit.inner.filesize += stabs_size; |
| 2841 | |
| 2842 | // Update dynamic symbol table. |
| 2843 | const dysymtab = &self.load_commands.items[self.dysymtab_cmd_index.?].Dysymtab; |
| 2844 | dysymtab.nlocalsym = symtab.nsyms; |
| 2845 | } |
| 2846 | |
| 2847 | fn writeSymbolTable(self: *Zld) !void { |
| 2848 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2849 | const symtab = &self.load_commands.items[self.symtab_cmd_index.?].Symtab; |
| 2850 | |
| 2851 | var locals = std.ArrayList(macho.nlist_64).init(self.allocator); |
| 2852 | defer locals.deinit(); |
| 2853 | |
| 2854 | for (self.locals.items()) |entries| { |
| 2855 | log.debug("'{s}': {} entries", .{ entries.key, entries.value.items.len }); |
| 2856 | // var symbol: ?macho.nlist_64 = null; |
| 2857 | for (entries.value.items) |entry| { |
| 2858 | log.debug(" | {}", .{entry.inner}); |
| 2859 | log.debug(" | {}", .{entry.tt}); |
| 2860 | log.debug(" | {s}", .{self.objects.items[entry.object_id].name}); |
| 2861 | try locals.append(entry.inner); |
| 2862 | } |
| 2863 | } |
| 2864 | const nlocals = locals.items.len; |
| 2865 | |
| 2866 | const nexports = self.exports.items().len; |
| 2867 | var exports = std.ArrayList(macho.nlist_64).init(self.allocator); |
| 2868 | defer exports.deinit(); |
| 2869 | |
| 2870 | try exports.ensureCapacity(nexports); |
| 2871 | for (self.exports.items()) |entry| { |
| 2872 | exports.appendAssumeCapacity(entry.value); |
| 2873 | } |
| 2874 | |
| 2875 | const has_tlv: bool = self.tlv_bootstrap != null; |
| 2876 | |
| 2877 | var nundefs = self.lazy_imports.items().len + self.nonlazy_imports.items().len; |
| 2878 | if (has_tlv) nundefs += 1; |
| 2879 | |
| 2880 | var undefs = std.ArrayList(macho.nlist_64).init(self.allocator); |
| 2881 | defer undefs.deinit(); |
| 2882 | |
| 2883 | try undefs.ensureCapacity(nundefs); |
| 2884 | for (self.lazy_imports.items()) |entry| { |
| 2885 | undefs.appendAssumeCapacity(entry.value.symbol); |
| 2886 | } |
| 2887 | for (self.nonlazy_imports.items()) |entry| { |
| 2888 | undefs.appendAssumeCapacity(entry.value.symbol); |
| 2889 | } |
| 2890 | if (has_tlv) { |
| 2891 | undefs.appendAssumeCapacity(self.tlv_bootstrap.?.symbol); |
| 2892 | } |
| 2893 | |
| 2894 | const locals_off = symtab.symoff + symtab.nsyms * @sizeOf(macho.nlist_64); |
| 2895 | const locals_size = nlocals * @sizeOf(macho.nlist_64); |
| 2896 | log.debug("writing local symbols from 0x{x} to 0x{x}", .{ locals_off, locals_size + locals_off }); |
| 2897 | try self.file.?.pwriteAll(mem.sliceAsBytes(locals.items), locals_off); |
| 2898 | |
| 2899 | const exports_off = locals_off + locals_size; |
| 2900 | const exports_size = nexports * @sizeOf(macho.nlist_64); |
| 2901 | log.debug("writing exported symbols from 0x{x} to 0x{x}", .{ exports_off, exports_size + exports_off }); |
| 2902 | try self.file.?.pwriteAll(mem.sliceAsBytes(exports.items), exports_off); |
| 2903 | |
| 2904 | const undefs_off = exports_off + exports_size; |
| 2905 | const undefs_size = nundefs * @sizeOf(macho.nlist_64); |
| 2906 | log.debug("writing undefined symbols from 0x{x} to 0x{x}", .{ undefs_off, undefs_size + undefs_off }); |
| 2907 | try self.file.?.pwriteAll(mem.sliceAsBytes(undefs.items), undefs_off); |
| 2908 | |
| 2909 | symtab.nsyms += @intCast(u32, nlocals + nexports + nundefs); |
| 2910 | seg.inner.filesize += locals_size + exports_size + undefs_size; |
| 2911 | |
| 2912 | // Update dynamic symbol table. |
| 2913 | const dysymtab = &self.load_commands.items[self.dysymtab_cmd_index.?].Dysymtab; |
| 2914 | dysymtab.nlocalsym += @intCast(u32, nlocals); |
| 2915 | dysymtab.iextdefsym = dysymtab.nlocalsym; |
| 2916 | dysymtab.nextdefsym = @intCast(u32, nexports); |
| 2917 | dysymtab.iundefsym = dysymtab.nlocalsym + dysymtab.nextdefsym; |
| 2918 | dysymtab.nundefsym = @intCast(u32, nundefs); |
| 2919 | } |
| 2920 | |
| 2921 | fn writeDynamicSymbolTable(self: *Zld) !void { |
| 2922 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2923 | const text_segment = &self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 2924 | const stubs = &text_segment.sections.items[self.stubs_section_index.?]; |
| 2925 | const data_const_segment = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment; |
| 2926 | const got = &data_const_segment.sections.items[self.got_section_index.?]; |
| 2927 | const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment; |
| 2928 | const la_symbol_ptr = &data_segment.sections.items[self.la_symbol_ptr_section_index.?]; |
| 2929 | const dysymtab = &self.load_commands.items[self.dysymtab_cmd_index.?].Dysymtab; |
| 2930 | |
| 2931 | const lazy = self.lazy_imports.items(); |
| 2932 | const nonlazy = self.nonlazy_imports.items(); |
| 2933 | const got_locals = self.nonlazy_pointers.items(); |
| 2934 | dysymtab.indirectsymoff = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2935 | dysymtab.nindirectsyms = @intCast(u32, lazy.len * 2 + nonlazy.len + got_locals.len); |
| 2936 | const needed_size = dysymtab.nindirectsyms * @sizeOf(u32); |
| 2937 | seg.inner.filesize += needed_size; |
| 2938 | |
| 2939 | log.debug("writing indirect symbol table from 0x{x} to 0x{x}", .{ |
| 2940 | dysymtab.indirectsymoff, |
| 2941 | dysymtab.indirectsymoff + needed_size, |
| 2942 | }); |
| 2943 | |
| 2944 | var buf = try self.allocator.alloc(u8, needed_size); |
| 2945 | defer self.allocator.free(buf); |
| 2946 | var stream = std.io.fixedBufferStream(buf); |
| 2947 | var writer = stream.writer(); |
| 2948 | |
| 2949 | stubs.reserved1 = 0; |
| 2950 | for (lazy) |_, i| { |
| 2951 | const symtab_idx = @intCast(u32, dysymtab.iundefsym + i); |
| 2952 | try writer.writeIntLittle(u32, symtab_idx); |
| 2953 | } |
| 2954 | |
| 2955 | const base_id = @intCast(u32, lazy.len); |
| 2956 | got.reserved1 = base_id; |
| 2957 | for (nonlazy) |_, i| { |
| 2958 | const symtab_idx = @intCast(u32, dysymtab.iundefsym + i + base_id); |
| 2959 | try writer.writeIntLittle(u32, symtab_idx); |
| 2960 | } |
| 2961 | // TODO there should be one common set of GOT entries. |
| 2962 | for (got_locals) |_| { |
| 2963 | try writer.writeIntLittle(u32, macho.INDIRECT_SYMBOL_LOCAL); |
| 2964 | } |
| 2965 | |
| 2966 | la_symbol_ptr.reserved1 = got.reserved1 + @intCast(u32, nonlazy.len) + @intCast(u32, got_locals.len); |
| 2967 | for (lazy) |_, i| { |
| 2968 | const symtab_idx = @intCast(u32, dysymtab.iundefsym + i); |
| 2969 | try writer.writeIntLittle(u32, symtab_idx); |
| 2970 | } |
| 2971 | |
| 2972 | try self.file.?.pwriteAll(buf, dysymtab.indirectsymoff); |
| 2973 | } |
| 2974 | |
| 2975 | fn writeStringTable(self: *Zld) !void { |
| 2976 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2977 | const symtab = &self.load_commands.items[self.symtab_cmd_index.?].Symtab; |
| 2978 | symtab.stroff = @intCast(u32, seg.inner.fileoff + seg.inner.filesize); |
| 2979 | symtab.strsize = @intCast(u32, mem.alignForwardGeneric(u64, self.strtab.items.len, @alignOf(u64))); |
| 2980 | seg.inner.filesize += symtab.strsize; |
| 2981 | |
| 2982 | log.debug("writing string table from 0x{x} to 0x{x}", .{ symtab.stroff, symtab.stroff + symtab.strsize }); |
| 2983 | |
| 2984 | try self.file.?.pwriteAll(self.strtab.items, symtab.stroff); |
| 2985 | |
| 2986 | if (symtab.strsize > self.strtab.items.len and self.arch.? == .x86_64) { |
| 2987 | // This is the last section, so we need to pad it out. |
| 2988 | try self.file.?.pwriteAll(&[_]u8{0}, seg.inner.fileoff + seg.inner.filesize - 1); |
| 2989 | } |
| 2990 | } |
| 2991 | |
| 2992 | fn writeDataInCode(self: *Zld) !void { |
| 2993 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 2994 | const dice_cmd = &self.load_commands.items[self.data_in_code_cmd_index.?].LinkeditData; |
| 2995 | const fileoff = seg.inner.fileoff + seg.inner.filesize; |
| 2996 | |
| 2997 | var buf = std.ArrayList(u8).init(self.allocator); |
| 2998 | defer buf.deinit(); |
| 2999 | |
| 3000 | const text_seg = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 3001 | const text_sect = text_seg.sections.items[self.text_section_index.?]; |
| 3002 | for (self.objects.items) |object, object_id| { |
| 3003 | const source_seg = object.load_commands.items[object.segment_cmd_index.?].Segment; |
| 3004 | const source_sect = source_seg.sections.items[object.text_section_index.?]; |
| 3005 | const target_mapping = self.mappings.get(.{ |
| 3006 | .object_id = @intCast(u16, object_id), |
| 3007 | .source_sect_id = object.text_section_index.?, |
| 3008 | }) orelse continue; |
| 3009 | |
| 3010 | try buf.ensureCapacity( |
| 3011 | buf.items.len + object.data_in_code_entries.items.len * @sizeOf(macho.data_in_code_entry), |
| 3012 | ); |
| 3013 | for (object.data_in_code_entries.items) |dice| { |
| 3014 | const new_dice: macho.data_in_code_entry = .{ |
| 3015 | .offset = text_sect.offset + target_mapping.offset + dice.offset, |
| 3016 | .length = dice.length, |
| 3017 | .kind = dice.kind, |
| 3018 | }; |
| 3019 | buf.appendSliceAssumeCapacity(mem.asBytes(&new_dice)); |
| 3020 | } |
| 3021 | } |
| 3022 | const datasize = @intCast(u32, buf.items.len); |
| 3023 | |
| 3024 | dice_cmd.dataoff = @intCast(u32, fileoff); |
| 3025 | dice_cmd.datasize = datasize; |
| 3026 | seg.inner.filesize += datasize; |
| 3027 | |
| 3028 | log.debug("writing data-in-code from 0x{x} to 0x{x}", .{ fileoff, fileoff + datasize }); |
| 3029 | |
| 3030 | try self.file.?.pwriteAll(buf.items, fileoff); |
| 3031 | } |
| 3032 | |
| 3033 | fn writeCodeSignaturePadding(self: *Zld) !void { |
| 3034 | const seg = &self.load_commands.items[self.linkedit_segment_cmd_index.?].Segment; |
| 3035 | const code_sig_cmd = &self.load_commands.items[self.code_signature_cmd_index.?].LinkeditData; |
| 3036 | const fileoff = seg.inner.fileoff + seg.inner.filesize; |
| 3037 | const needed_size = CodeSignature.calcCodeSignaturePaddingSize( |
| 3038 | self.out_path.?, |
| 3039 | fileoff, |
| 3040 | self.page_size.?, |
| 3041 | ); |
| 3042 | code_sig_cmd.dataoff = @intCast(u32, fileoff); |
| 3043 | code_sig_cmd.datasize = needed_size; |
| 3044 | |
| 3045 | // Advance size of __LINKEDIT segment |
| 3046 | seg.inner.filesize += needed_size; |
| 3047 | seg.inner.vmsize = mem.alignForwardGeneric(u64, seg.inner.filesize, self.page_size.?); |
| 3048 | |
| 3049 | log.debug("writing code signature padding from 0x{x} to 0x{x}", .{ fileoff, fileoff + needed_size }); |
| 3050 | |
| 3051 | // Pad out the space. We need to do this to calculate valid hashes for everything in the file |
| 3052 | // except for code signature data. |
| 3053 | try self.file.?.pwriteAll(&[_]u8{0}, fileoff + needed_size - 1); |
| 3054 | } |
| 3055 | |
| 3056 | fn writeCodeSignature(self: *Zld) !void { |
| 3057 | const text_seg = self.load_commands.items[self.text_segment_cmd_index.?].Segment; |
| 3058 | const code_sig_cmd = self.load_commands.items[self.code_signature_cmd_index.?].LinkeditData; |
| 3059 | |
| 3060 | var code_sig = CodeSignature.init(self.allocator, self.page_size.?); |
| 3061 | defer code_sig.deinit(); |
| 3062 | try code_sig.calcAdhocSignature( |
| 3063 | self.file.?, |
| 3064 | self.out_path.?, |
| 3065 | text_seg.inner, |
| 3066 | code_sig_cmd, |
| 3067 | .Exe, |
| 3068 | ); |
| 3069 | |
| 3070 | var buffer = try self.allocator.alloc(u8, code_sig.size()); |
| 3071 | defer self.allocator.free(buffer); |
| 3072 | var stream = std.io.fixedBufferStream(buffer); |
| 3073 | try code_sig.write(stream.writer()); |
| 3074 | |
| 3075 | log.debug("writing code signature from 0x{x} to 0x{x}", .{ code_sig_cmd.dataoff, code_sig_cmd.dataoff + buffer.len }); |
| 3076 | |
| 3077 | try self.file.?.pwriteAll(buffer, code_sig_cmd.dataoff); |
| 3078 | } |
| 3079 | |
| 3080 | fn writeLoadCommands(self: *Zld) !void { |
| 3081 | var sizeofcmds: u32 = 0; |
| 3082 | for (self.load_commands.items) |lc| { |
| 3083 | sizeofcmds += lc.cmdsize(); |
| 3084 | } |
| 3085 | |
| 3086 | var buffer = try self.allocator.alloc(u8, sizeofcmds); |
| 3087 | defer self.allocator.free(buffer); |
| 3088 | var writer = std.io.fixedBufferStream(buffer).writer(); |
| 3089 | for (self.load_commands.items) |lc| { |
| 3090 | try lc.write(writer); |
| 3091 | } |
| 3092 | |
| 3093 | const off = @sizeOf(macho.mach_header_64); |
| 3094 | log.debug("writing {} load commands from 0x{x} to 0x{x}", .{ self.load_commands.items.len, off, off + sizeofcmds }); |
| 3095 | try self.file.?.pwriteAll(buffer, off); |
| 3096 | } |
| 3097 | |
| 3098 | fn writeHeader(self: *Zld) !void { |
| 3099 | var header: macho.mach_header_64 = undefined; |
| 3100 | header.magic = macho.MH_MAGIC_64; |
| 3101 | |
| 3102 | const CpuInfo = struct { |
| 3103 | cpu_type: macho.cpu_type_t, |
| 3104 | cpu_subtype: macho.cpu_subtype_t, |
| 3105 | }; |
| 3106 | |
| 3107 | const cpu_info: CpuInfo = switch (self.arch.?) { |
| 3108 | .aarch64 => .{ |
| 3109 | .cpu_type = macho.CPU_TYPE_ARM64, |
| 3110 | .cpu_subtype = macho.CPU_SUBTYPE_ARM_ALL, |
| 3111 | }, |
| 3112 | .x86_64 => .{ |
| 3113 | .cpu_type = macho.CPU_TYPE_X86_64, |
| 3114 | .cpu_subtype = macho.CPU_SUBTYPE_X86_64_ALL, |
| 3115 | }, |
| 3116 | else => return error.UnsupportedCpuArchitecture, |
| 3117 | }; |
| 3118 | header.cputype = cpu_info.cpu_type; |
| 3119 | header.cpusubtype = cpu_info.cpu_subtype; |
| 3120 | header.filetype = macho.MH_EXECUTE; |
| 3121 | header.flags = macho.MH_NOUNDEFS | macho.MH_DYLDLINK | macho.MH_PIE | macho.MH_TWOLEVEL; |
| 3122 | header.reserved = 0; |
| 3123 | |
| 3124 | if (self.tlv_section_index) |_| |
| 3125 | header.flags |= macho.MH_HAS_TLV_DESCRIPTORS; |
| 3126 | |
| 3127 | header.ncmds = @intCast(u32, self.load_commands.items.len); |
| 3128 | header.sizeofcmds = 0; |
| 3129 | for (self.load_commands.items) |cmd| { |
| 3130 | header.sizeofcmds += cmd.cmdsize(); |
| 3131 | } |
| 3132 | log.debug("writing Mach-O header {}", .{header}); |
| 3133 | try self.file.?.pwriteAll(mem.asBytes(&header), 0); |
| 3134 | } |
| 3135 | |
| 3136 | pub fn makeStaticString(bytes: []const u8) [16]u8 { |
| 3137 | var buf = [_]u8{0} ** 16; |
| 3138 | assert(bytes.len <= buf.len); |
| 3139 | mem.copy(u8, &buf, bytes); |
| 3140 | return buf; |
| 3141 | } |
| 3142 | |
| 3143 | fn makeString(self: *Zld, bytes: []const u8) !u32 { |
| 3144 | try self.strtab.ensureCapacity(self.allocator, self.strtab.items.len + bytes.len + 1); |
| 3145 | const offset = @intCast(u32, self.strtab.items.len); |
| 3146 | log.debug("writing new string '{s}' into string table at offset 0x{x}", .{ bytes, offset }); |
| 3147 | self.strtab.appendSliceAssumeCapacity(bytes); |
| 3148 | self.strtab.appendAssumeCapacity(0); |
| 3149 | return offset; |
| 3150 | } |
| 3151 | |
| 3152 | fn getString(self: *const Zld, str_off: u32) []const u8 { |
| 3153 | assert(str_off < self.strtab.items.len); |
| 3154 | return mem.spanZ(@ptrCast([*:0]const u8, self.strtab.items.ptr + str_off)); |
| 3155 | } |
| 3156 | |
| 3157 | pub fn parseName(name: *const [16]u8) []const u8 { |
| 3158 | const len = mem.indexOfScalar(u8, name, @as(u8, 0)) orelse name.len; |
| 3159 | return name[0..len]; |
| 3160 | } |
| 3161 | |
| 3162 | fn isLocal(sym: *const macho.nlist_64) callconv(.Inline) bool { |
| 3163 | if (isExtern(sym)) return false; |
| 3164 | const tt = macho.N_TYPE & sym.n_type; |
| 3165 | return tt == macho.N_SECT; |
| 3166 | } |
| 3167 | |
| 3168 | fn isExport(sym: *const macho.nlist_64) callconv(.Inline) bool { |
| 3169 | if (!isExtern(sym)) return false; |
| 3170 | const tt = macho.N_TYPE & sym.n_type; |
| 3171 | return tt == macho.N_SECT; |
| 3172 | } |
| 3173 | |
| 3174 | fn isImport(sym: *const macho.nlist_64) callconv(.Inline) bool { |
| 3175 | if (!isExtern(sym)) return false; |
| 3176 | const tt = macho.N_TYPE & sym.n_type; |
| 3177 | return tt == macho.N_UNDF; |
| 3178 | } |
| 3179 | |
| 3180 | fn isExtern(sym: *const macho.nlist_64) callconv(.Inline) bool { |
| 3181 | if ((sym.n_type & macho.N_EXT) == 0) return false; |
| 3182 | return (sym.n_type & macho.N_PEXT) == 0; |
| 3183 | } |
| 3184 | |
| 3185 | fn isWeakDef(sym: *const macho.nlist_64) callconv(.Inline) bool { |
| 3186 | return (sym.n_desc & macho.N_WEAK_DEF) != 0; |
| 3187 | } |
| 3188 | |
| 3189 | fn aarch64IsArithmetic(inst: *const [4]u8) callconv(.Inline) bool { |
| 3190 | const group_decode = @truncate(u5, inst[3]); |
| 3191 | return ((group_decode >> 2) == 4); |
| 3192 | } |
Jakub Konka <kubkon@jakubkonka.com> 2021-03-18 19:14:17+01:00
GitHub <noreply@github.com> 2021-03-18 19:14:17+01:00