Files
zig/src/link/MachO/InternalObject.zig
2025-07-07 22:43:52 -07:00

907 lines
34 KiB
Zig

index: File.Index,
sections: std.MultiArrayList(Section) = .{},
atoms: std.ArrayListUnmanaged(Atom) = .empty,
atoms_indexes: std.ArrayListUnmanaged(Atom.Index) = .empty,
atoms_extra: std.ArrayListUnmanaged(u32) = .empty,
symtab: std.ArrayListUnmanaged(macho.nlist_64) = .empty,
strtab: std.ArrayListUnmanaged(u8) = .empty,
symbols: std.ArrayListUnmanaged(Symbol) = .empty,
symbols_extra: std.ArrayListUnmanaged(u32) = .empty,
globals: std.ArrayListUnmanaged(MachO.SymbolResolver.Index) = .empty,
objc_methnames: std.ArrayListUnmanaged(u8) = .empty,
objc_selrefs: [@sizeOf(u64)]u8 = [_]u8{0} ** @sizeOf(u64),
force_undefined: std.ArrayListUnmanaged(Symbol.Index) = .empty,
entry_index: ?Symbol.Index = null,
dyld_stub_binder_index: ?Symbol.Index = null,
dyld_private_index: ?Symbol.Index = null,
objc_msg_send_index: ?Symbol.Index = null,
mh_execute_header_index: ?Symbol.Index = null,
mh_dylib_header_index: ?Symbol.Index = null,
dso_handle_index: ?Symbol.Index = null,
boundary_symbols: std.ArrayListUnmanaged(Symbol.Index) = .empty,
output_symtab_ctx: MachO.SymtabCtx = .{},
pub fn deinit(self: *InternalObject, allocator: Allocator) void {
for (self.sections.items(.relocs)) |*relocs| {
relocs.deinit(allocator);
}
self.sections.deinit(allocator);
self.atoms.deinit(allocator);
self.atoms_indexes.deinit(allocator);
self.atoms_extra.deinit(allocator);
self.symtab.deinit(allocator);
self.strtab.deinit(allocator);
self.symbols.deinit(allocator);
self.symbols_extra.deinit(allocator);
self.globals.deinit(allocator);
self.objc_methnames.deinit(allocator);
self.force_undefined.deinit(allocator);
self.boundary_symbols.deinit(allocator);
}
pub fn init(self: *InternalObject, allocator: Allocator) !void {
// Atom at index 0 is reserved as null atom.
try self.atoms.append(allocator, .{ .extra = try self.addAtomExtra(allocator, .{}) });
// Null byte in strtab
try self.strtab.append(allocator, 0);
}
pub fn initSymbols(self: *InternalObject, macho_file: *MachO) !void {
const newSymbolAssumeCapacity = struct {
fn newSymbolAssumeCapacity(obj: *InternalObject, name: MachO.String, args: struct {
type: u8 = macho.N_UNDF | macho.N_EXT,
desc: u16 = 0,
}) Symbol.Index {
const index = obj.addSymbolAssumeCapacity();
const symbol = &obj.symbols.items[index];
symbol.name = name;
symbol.extra = obj.addSymbolExtraAssumeCapacity(.{});
symbol.flags.dyn_ref = args.desc & macho.REFERENCED_DYNAMICALLY != 0;
symbol.visibility = if (args.type & macho.N_EXT != 0) blk: {
break :blk if (args.type & macho.N_PEXT != 0) .hidden else .global;
} else .local;
const nlist_idx: u32 = @intCast(obj.symtab.items.len);
const nlist = obj.symtab.addOneAssumeCapacity();
nlist.* = .{
.n_strx = name.pos,
.n_type = args.type,
.n_sect = 0,
.n_desc = args.desc,
.n_value = 0,
};
symbol.nlist_idx = nlist_idx;
return index;
}
}.newSymbolAssumeCapacity;
const gpa = macho_file.base.comp.gpa;
var nsyms = macho_file.base.comp.force_undefined_symbols.keys().len;
nsyms += 1; // dyld_stub_binder
nsyms += 1; // _objc_msgSend
if (!macho_file.base.isDynLib()) {
nsyms += 1; // entry
nsyms += 1; // __mh_execute_header
} else {
nsyms += 1; // __mh_dylib_header
}
nsyms += 1; // ___dso_handle
nsyms += 1; // dyld_private
try self.symbols.ensureTotalCapacityPrecise(gpa, nsyms);
try self.symbols_extra.ensureTotalCapacityPrecise(gpa, nsyms * @sizeOf(Symbol.Extra));
try self.symtab.ensureTotalCapacityPrecise(gpa, nsyms);
try self.globals.ensureTotalCapacityPrecise(gpa, nsyms);
self.globals.resize(gpa, nsyms) catch unreachable;
@memset(self.globals.items, 0);
try self.force_undefined.ensureTotalCapacityPrecise(gpa, macho_file.base.comp.force_undefined_symbols.keys().len);
for (macho_file.base.comp.force_undefined_symbols.keys()) |name| {
self.force_undefined.addOneAssumeCapacity().* = newSymbolAssumeCapacity(self, try self.addString(gpa, name), .{});
}
self.dyld_stub_binder_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "dyld_stub_binder"), .{});
self.objc_msg_send_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "_objc_msgSend"), .{});
if (!macho_file.base.isDynLib()) {
self.entry_index = newSymbolAssumeCapacity(self, try self.addString(gpa, macho_file.entry_name orelse "_main"), .{});
self.mh_execute_header_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "__mh_execute_header"), .{
.type = macho.N_SECT | macho.N_EXT,
.desc = macho.REFERENCED_DYNAMICALLY,
});
} else {
self.mh_dylib_header_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "__mh_dylib_header"), .{
.type = macho.N_SECT | macho.N_EXT,
});
}
self.dso_handle_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "___dso_handle"), .{
.type = macho.N_SECT | macho.N_EXT,
});
self.dyld_private_index = newSymbolAssumeCapacity(self, try self.addString(gpa, "dyld_private"), .{
.type = macho.N_SECT,
});
}
pub fn resolveSymbols(self: *InternalObject, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();
const gpa = macho_file.base.comp.gpa;
for (self.symtab.items, self.globals.items, 0..) |nlist, *global, i| {
const gop = try macho_file.resolver.getOrPut(gpa, .{
.index = @intCast(i),
.file = self.index,
}, macho_file);
if (!gop.found_existing) {
gop.ref.* = .{ .index = 0, .file = 0 };
}
global.* = gop.index;
if (nlist.undf()) continue;
if (gop.ref.getFile(macho_file) == null) {
gop.ref.* = .{ .index = @intCast(i), .file = self.index };
continue;
}
if (self.asFile().getSymbolRank(.{
.archive = false,
.weak = false,
.tentative = false,
}) < gop.ref.getSymbol(macho_file).?.getSymbolRank(macho_file)) {
gop.ref.* = .{ .index = @intCast(i), .file = self.index };
}
}
}
pub fn resolveBoundarySymbols(self: *InternalObject, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();
const gpa = macho_file.base.comp.gpa;
var boundary_symbols = std.StringArrayHashMap(MachO.Ref).init(gpa);
defer boundary_symbols.deinit();
for (macho_file.objects.items) |index| {
const object = macho_file.getFile(index).?.object;
for (object.symbols.items, 0..) |sym, i| {
const nlist = object.symtab.items(.nlist)[i];
if (!nlist.undf() or !nlist.ext()) continue;
const ref = object.getSymbolRef(@intCast(i), macho_file);
if (ref.getFile(macho_file) != null) continue;
const name = sym.getName(macho_file);
if (mem.startsWith(u8, name, "segment$start$") or
mem.startsWith(u8, name, "segment$end$") or
mem.startsWith(u8, name, "section$start$") or
mem.startsWith(u8, name, "section$end$"))
{
const gop = try boundary_symbols.getOrPut(name);
if (!gop.found_existing) {
gop.value_ptr.* = .{ .index = @intCast(i), .file = index };
}
}
}
}
const nsyms = boundary_symbols.values().len;
try self.boundary_symbols.ensureTotalCapacityPrecise(gpa, nsyms);
try self.symbols.ensureUnusedCapacity(gpa, nsyms);
try self.symtab.ensureUnusedCapacity(gpa, nsyms);
try self.symbols_extra.ensureUnusedCapacity(gpa, nsyms * @sizeOf(Symbol.Extra));
try self.globals.ensureUnusedCapacity(gpa, nsyms);
for (boundary_symbols.keys(), boundary_symbols.values()) |name, ref| {
const name_str = try self.addString(gpa, name);
const sym_index = self.addSymbolAssumeCapacity();
self.boundary_symbols.appendAssumeCapacity(sym_index);
const sym = &self.symbols.items[sym_index];
sym.name = name_str;
sym.visibility = .local;
const nlist_idx: u32 = @intCast(self.symtab.items.len);
const nlist = self.symtab.addOneAssumeCapacity();
nlist.* = .{
.n_strx = name_str.pos,
.n_type = macho.N_SECT,
.n_sect = 0,
.n_desc = 0,
.n_value = 0,
};
sym.nlist_idx = nlist_idx;
sym.extra = self.addSymbolExtraAssumeCapacity(.{});
const idx = ref.getFile(macho_file).?.object.globals.items[ref.index];
self.globals.addOneAssumeCapacity().* = idx;
macho_file.resolver.values.items[idx - 1] = .{ .index = sym_index, .file = self.index };
}
}
pub fn markLive(self: *InternalObject, macho_file: *MachO) void {
const tracy = trace(@src());
defer tracy.end();
for (0..self.symbols.items.len) |i| {
const nlist = self.symtab.items[i];
if (!nlist.ext()) continue;
const ref = self.getSymbolRef(@intCast(i), macho_file);
const file = ref.getFile(macho_file) orelse continue;
if (file == .object and !file.object.alive) {
file.object.alive = true;
file.object.markLive(macho_file);
}
}
}
/// Creates a fake input sections __TEXT,__objc_methname and __DATA,__objc_selrefs.
pub fn addObjcMsgsendSections(self: *InternalObject, sym_name: []const u8, macho_file: *MachO) !Symbol.Index {
const methname_sym_index = try self.addObjcMethnameSection(sym_name, macho_file);
return try self.addObjcSelrefsSection(methname_sym_index, macho_file);
}
fn addObjcMethnameSection(self: *InternalObject, methname: []const u8, macho_file: *MachO) !Symbol.Index {
const gpa = macho_file.base.comp.gpa;
const atom_index = try self.addAtom(gpa);
try self.atoms_indexes.append(gpa, atom_index);
const atom = self.getAtom(atom_index).?;
atom.size = methname.len + 1;
atom.alignment = .@"1";
const n_sect = try self.addSection(gpa, "__TEXT", "__objc_methname");
const sect = &self.sections.items(.header)[n_sect];
sect.flags = macho.S_CSTRING_LITERALS;
sect.size = atom.size;
sect.@"align" = 0;
atom.n_sect = n_sect;
self.sections.items(.extra)[n_sect].is_objc_methname = true;
sect.offset = @intCast(self.objc_methnames.items.len);
try self.objc_methnames.ensureUnusedCapacity(gpa, methname.len + 1);
self.objc_methnames.print(gpa, "{s}\x00", .{methname}) catch unreachable;
const name_str = try self.addString(gpa, "ltmp");
const sym_index = try self.addSymbol(gpa);
const sym = &self.symbols.items[sym_index];
sym.name = name_str;
sym.atom_ref = .{ .index = atom_index, .file = self.index };
sym.extra = try self.addSymbolExtra(gpa, .{});
const nlist_idx: u32 = @intCast(self.symtab.items.len);
const nlist = try self.symtab.addOne(gpa);
nlist.* = .{
.n_strx = name_str.pos,
.n_type = macho.N_SECT,
.n_sect = @intCast(n_sect + 1),
.n_desc = 0,
.n_value = 0,
};
sym.nlist_idx = nlist_idx;
try self.globals.append(gpa, 0);
return sym_index;
}
fn addObjcSelrefsSection(self: *InternalObject, methname_sym_index: Symbol.Index, macho_file: *MachO) !Symbol.Index {
const gpa = macho_file.base.comp.gpa;
const atom_index = try self.addAtom(gpa);
try self.atoms_indexes.append(gpa, atom_index);
const atom = self.getAtom(atom_index).?;
atom.size = @sizeOf(u64);
atom.alignment = .@"8";
const n_sect = try self.addSection(gpa, "__DATA", "__objc_selrefs");
const sect = &self.sections.items(.header)[n_sect];
sect.flags = macho.S_LITERAL_POINTERS | macho.S_ATTR_NO_DEAD_STRIP;
sect.offset = 0;
sect.size = atom.size;
sect.@"align" = 3;
atom.n_sect = n_sect;
self.sections.items(.extra)[n_sect].is_objc_selref = true;
const relocs = &self.sections.items(.relocs)[n_sect];
try relocs.ensureUnusedCapacity(gpa, 1);
relocs.appendAssumeCapacity(.{
.tag = .@"extern",
.offset = 0,
.target = methname_sym_index,
.addend = 0,
.type = .unsigned,
.meta = .{
.pcrel = false,
.length = 3,
.symbolnum = 0, // Only used when synthesising unwind records so can be anything
.has_subtractor = false,
},
});
atom.addExtra(.{ .rel_index = 0, .rel_count = 1 }, macho_file);
const sym_index = try self.addSymbol(gpa);
const sym = &self.symbols.items[sym_index];
sym.atom_ref = .{ .index = atom_index, .file = self.index };
sym.extra = try self.addSymbolExtra(gpa, .{});
const nlist_idx: u32 = @intCast(self.symtab.items.len);
const nlist = try self.symtab.addOne(gpa);
nlist.* = .{
.n_strx = 0,
.n_type = macho.N_SECT,
.n_sect = @intCast(n_sect + 1),
.n_desc = 0,
.n_value = 0,
};
sym.nlist_idx = nlist_idx;
try self.globals.append(gpa, 0);
atom.addExtra(.{ .literal_symbol_index = sym_index }, macho_file);
return sym_index;
}
pub fn resolveObjcMsgSendSymbols(self: *InternalObject, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();
const gpa = macho_file.base.comp.gpa;
var objc_msgsend_syms = std.StringArrayHashMap(MachO.Ref).init(gpa);
defer objc_msgsend_syms.deinit();
for (macho_file.objects.items) |index| {
const object = macho_file.getFile(index).?.object;
for (object.symbols.items, 0..) |sym, i| {
const nlist = object.symtab.items(.nlist)[i];
if (!nlist.ext()) continue;
if (!nlist.undf()) continue;
const ref = object.getSymbolRef(@intCast(i), macho_file);
if (ref.getFile(macho_file) != null) continue;
const name = sym.getName(macho_file);
if (mem.startsWith(u8, name, "_objc_msgSend$")) {
const gop = try objc_msgsend_syms.getOrPut(name);
if (!gop.found_existing) {
gop.value_ptr.* = .{ .index = @intCast(i), .file = index };
}
}
}
}
for (objc_msgsend_syms.keys(), objc_msgsend_syms.values()) |sym_name, ref| {
const name = MachO.eatPrefix(sym_name, "_objc_msgSend$").?;
const selrefs_index = try self.addObjcMsgsendSections(name, macho_file);
const name_str = try self.addString(gpa, sym_name);
const sym_index = try self.addSymbol(gpa);
const sym = &self.symbols.items[sym_index];
sym.name = name_str;
sym.visibility = .hidden;
const nlist_idx: u32 = @intCast(self.symtab.items.len);
const nlist = try self.symtab.addOne(gpa);
nlist.* = .{
.n_strx = name_str.pos,
.n_type = macho.N_SECT | macho.N_EXT | macho.N_PEXT,
.n_sect = 0,
.n_desc = 0,
.n_value = 0,
};
sym.nlist_idx = nlist_idx;
sym.extra = try self.addSymbolExtra(gpa, .{ .objc_selrefs = selrefs_index });
sym.setSectionFlags(.{ .objc_stubs = true });
const idx = ref.getFile(macho_file).?.object.globals.items[ref.index];
try self.globals.append(gpa, idx);
macho_file.resolver.values.items[idx - 1] = .{ .index = sym_index, .file = self.index };
}
}
pub fn resolveLiterals(self: *InternalObject, lp: *MachO.LiteralPool, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();
const gpa = macho_file.base.comp.gpa;
var buffer = std.ArrayList(u8).init(gpa);
defer buffer.deinit();
const slice = self.sections.slice();
for (slice.items(.header), self.getAtoms()) |header, atom_index| {
if (!Object.isPtrLiteral(header)) continue;
const atom = self.getAtom(atom_index).?;
const relocs = atom.getRelocs(macho_file);
assert(relocs.len == 1);
const rel = relocs[0];
assert(rel.tag == .@"extern");
const target = rel.getTargetSymbol(atom.*, macho_file).getAtom(macho_file).?;
const target_size = try macho_file.cast(usize, target.size);
try buffer.ensureUnusedCapacity(target_size);
buffer.resize(target_size) catch unreachable;
const section_data = try self.getSectionData(target.n_sect, macho_file);
@memcpy(buffer.items, section_data);
const res = try lp.insert(gpa, header.type(), buffer.items);
buffer.clearRetainingCapacity();
if (!res.found_existing) {
res.ref.* = .{ .index = atom.getExtra(macho_file).literal_symbol_index, .file = self.index };
} else {
const lp_sym = lp.getSymbol(res.index, macho_file);
const lp_atom = lp_sym.getAtom(macho_file).?;
lp_atom.alignment = lp_atom.alignment.max(atom.alignment);
atom.setAlive(false);
}
atom.addExtra(.{ .literal_pool_index = res.index }, macho_file);
}
}
pub fn dedupLiterals(self: *InternalObject, lp: MachO.LiteralPool, macho_file: *MachO) void {
const tracy = trace(@src());
defer tracy.end();
for (self.getAtoms()) |atom_index| {
const atom = self.getAtom(atom_index) orelse continue;
if (!atom.isAlive()) continue;
const relocs = blk: {
const extra = atom.getExtra(macho_file);
const relocs = self.sections.items(.relocs)[atom.n_sect].items;
break :blk relocs[extra.rel_index..][0..extra.rel_count];
};
for (relocs) |*rel| {
if (rel.tag != .@"extern") continue;
const target_sym_ref = rel.getTargetSymbolRef(atom.*, macho_file);
const file = target_sym_ref.getFile(macho_file) orelse continue;
if (file.getIndex() != self.index) continue;
const target_sym = target_sym_ref.getSymbol(macho_file).?;
const target_atom = target_sym.getAtom(macho_file) orelse continue;
if (!Object.isPtrLiteral(target_atom.getInputSection(macho_file))) continue;
const lp_index = target_atom.getExtra(macho_file).literal_pool_index;
const lp_sym = lp.getSymbol(lp_index, macho_file);
const lp_atom_ref = lp_sym.atom_ref;
if (target_atom.atom_index != lp_atom_ref.index or target_atom.file != lp_atom_ref.file) {
target_sym.atom_ref = lp_atom_ref;
}
}
}
for (self.symbols.items) |*sym| {
if (!sym.getSectionFlags().objc_stubs) continue;
const extra = sym.getExtra(macho_file);
const file = sym.getFile(macho_file).?;
if (file.getIndex() != self.index) continue;
const tsym = switch (file) {
.dylib => unreachable,
inline else => |x| &x.symbols.items[extra.objc_selrefs],
};
const atom = tsym.getAtom(macho_file) orelse continue;
if (!Object.isPtrLiteral(atom.getInputSection(macho_file))) continue;
const lp_index = atom.getExtra(macho_file).literal_pool_index;
const lp_sym = lp.getSymbol(lp_index, macho_file);
const lp_atom_ref = lp_sym.atom_ref;
if (atom.atom_index != lp_atom_ref.index or atom.file != lp_atom_ref.file) {
tsym.atom_ref = lp_atom_ref;
}
}
}
pub fn scanRelocs(self: *InternalObject, macho_file: *MachO) void {
const tracy = trace(@src());
defer tracy.end();
if (self.getEntryRef(macho_file)) |ref| {
if (ref.getFile(macho_file) != null) {
const sym = ref.getSymbol(macho_file).?;
if (sym.flags.import) sym.setSectionFlags(.{ .stubs = true });
}
}
if (self.getDyldStubBinderRef(macho_file)) |ref| {
if (ref.getFile(macho_file) != null) {
const sym = ref.getSymbol(macho_file).?;
sym.setSectionFlags(.{ .needs_got = true });
}
}
if (self.getObjcMsgSendRef(macho_file)) |ref| {
if (ref.getFile(macho_file) != null) {
const sym = ref.getSymbol(macho_file).?;
// TODO is it always needed, or only if we are synthesising fast stubs
sym.setSectionFlags(.{ .needs_got = true });
}
}
}
pub fn checkUndefs(self: InternalObject, macho_file: *MachO) !void {
const addUndef = struct {
fn addUndef(mf: *MachO, index: MachO.SymbolResolver.Index, tag: anytype) !void {
const gpa = mf.base.comp.gpa;
mf.undefs_mutex.lock();
defer mf.undefs_mutex.unlock();
const gop = try mf.undefs.getOrPut(gpa, index);
if (!gop.found_existing) {
gop.value_ptr.* = tag;
}
}
}.addUndef;
for (self.force_undefined.items) |index| {
const ref = self.getSymbolRef(index, macho_file);
if (ref.getFile(macho_file) == null) {
try addUndef(macho_file, self.globals.items[index], .force_undefined);
}
}
if (self.getEntryRef(macho_file)) |ref| {
if (ref.getFile(macho_file) == null) {
try addUndef(macho_file, self.globals.items[self.entry_index.?], .entry);
}
}
if (self.getDyldStubBinderRef(macho_file)) |ref| {
if (ref.getFile(macho_file) == null and macho_file.stubs.symbols.items.len > 0) {
try addUndef(macho_file, self.globals.items[self.dyld_stub_binder_index.?], .dyld_stub_binder);
}
}
if (self.getObjcMsgSendRef(macho_file)) |ref| {
if (ref.getFile(macho_file) == null and self.needsObjcMsgsendSymbol()) {
try addUndef(macho_file, self.globals.items[self.objc_msg_send_index.?], .objc_msgsend);
}
}
}
pub fn allocateSyntheticSymbols(self: *InternalObject, macho_file: *MachO) void {
const text_seg = macho_file.getTextSegment();
if (self.mh_execute_header_index) |index| {
const ref = self.getSymbolRef(index, macho_file);
if (ref.getFile(macho_file)) |file| {
if (file.getIndex() == self.index) {
const sym = &self.symbols.items[index];
sym.value = text_seg.vmaddr;
}
}
}
if (macho_file.data_sect_index) |idx| {
const sect = macho_file.sections.items(.header)[idx];
for (&[_]?Symbol.Index{
self.dso_handle_index,
self.mh_dylib_header_index,
self.dyld_private_index,
}) |maybe_index| {
if (maybe_index) |index| {
const ref = self.getSymbolRef(index, macho_file);
if (ref.getFile(macho_file)) |file| {
if (file.getIndex() == self.index) {
const sym = &self.symbols.items[index];
sym.value = sect.addr;
sym.out_n_sect = idx;
}
}
}
}
}
}
pub fn calcSymtabSize(self: *InternalObject, macho_file: *MachO) void {
for (self.symbols.items, 0..) |*sym, i| {
const ref = self.getSymbolRef(@intCast(i), macho_file);
const file = ref.getFile(macho_file) orelse continue;
if (file.getIndex() != self.index) continue;
if (sym.getName(macho_file).len == 0) continue;
if (macho_file.discard_local_symbols and sym.isLocal()) continue;
sym.flags.output_symtab = true;
if (sym.isLocal()) {
sym.addExtra(.{ .symtab = self.output_symtab_ctx.nlocals }, macho_file);
self.output_symtab_ctx.nlocals += 1;
} else if (sym.flags.@"export") {
sym.addExtra(.{ .symtab = self.output_symtab_ctx.nexports }, macho_file);
self.output_symtab_ctx.nexports += 1;
} else {
assert(sym.flags.import);
sym.addExtra(.{ .symtab = self.output_symtab_ctx.nimports }, macho_file);
self.output_symtab_ctx.nimports += 1;
}
self.output_symtab_ctx.strsize += @as(u32, @intCast(sym.getName(macho_file).len + 1));
}
}
pub fn writeAtoms(self: *InternalObject, macho_file: *MachO) !void {
const tracy = trace(@src());
defer tracy.end();
for (self.getAtoms()) |atom_index| {
const atom = self.getAtom(atom_index) orelse continue;
if (!atom.isAlive()) continue;
const sect = atom.getInputSection(macho_file);
if (sect.isZerofill()) continue;
const off = try macho_file.cast(usize, atom.value);
const size = try macho_file.cast(usize, atom.size);
const buffer = macho_file.sections.items(.out)[atom.out_n_sect].items[off..][0..size];
const section_data = try self.getSectionData(atom.n_sect, macho_file);
@memcpy(buffer, section_data);
try atom.resolveRelocs(macho_file, buffer);
}
}
pub fn writeSymtab(self: InternalObject, macho_file: *MachO, ctx: anytype) void {
var n_strx = self.output_symtab_ctx.stroff;
for (self.symbols.items, 0..) |sym, i| {
const ref = self.getSymbolRef(@intCast(i), macho_file);
const file = ref.getFile(macho_file) orelse continue;
if (file.getIndex() != self.index) continue;
const idx = sym.getOutputSymtabIndex(macho_file) orelse continue;
const out_sym = &ctx.symtab.items[idx];
out_sym.n_strx = n_strx;
sym.setOutputSym(macho_file, out_sym);
const name = sym.getName(macho_file);
@memcpy(ctx.strtab.items[n_strx..][0..name.len], name);
n_strx += @intCast(name.len);
ctx.strtab.items[n_strx] = 0;
n_strx += 1;
}
}
fn addSection(self: *InternalObject, allocator: Allocator, segname: []const u8, sectname: []const u8) !u32 {
const n_sect = @as(u32, @intCast(try self.sections.addOne(allocator)));
self.sections.set(n_sect, .{
.header = .{
.sectname = MachO.makeStaticString(sectname),
.segname = MachO.makeStaticString(segname),
},
});
return n_sect;
}
fn getSectionData(self: *const InternalObject, index: u32, macho_file: *MachO) error{LinkFailure}![]const u8 {
const slice = self.sections.slice();
assert(index < slice.items(.header).len);
const sect = slice.items(.header)[index];
const extra = slice.items(.extra)[index];
if (extra.is_objc_methname) {
const size = try macho_file.cast(usize, sect.size);
return self.objc_methnames.items[sect.offset..][0..size];
} else if (extra.is_objc_selref)
return &self.objc_selrefs
else
@panic("ref to non-existent section");
}
pub fn addString(self: *InternalObject, allocator: Allocator, string: []const u8) !MachO.String {
const off: u32 = @intCast(self.strtab.items.len);
try self.strtab.ensureUnusedCapacity(allocator, string.len + 1);
self.strtab.appendSliceAssumeCapacity(string);
self.strtab.appendAssumeCapacity(0);
return .{ .pos = off, .len = @intCast(string.len + 1) };
}
pub fn getString(self: InternalObject, string: MachO.String) [:0]const u8 {
assert(string.pos < self.strtab.items.len and string.pos + string.len <= self.strtab.items.len);
if (string.len == 0) return "";
return self.strtab.items[string.pos..][0 .. string.len - 1 :0];
}
pub fn asFile(self: *InternalObject) File {
return .{ .internal = self };
}
pub fn getAtomRelocs(self: *const InternalObject, atom: Atom, macho_file: *MachO) []const Relocation {
const extra = atom.getExtra(macho_file);
const relocs = self.sections.items(.relocs)[atom.n_sect];
return relocs.items[extra.rel_index..][0..extra.rel_count];
}
fn addAtom(self: *InternalObject, allocator: Allocator) !Atom.Index {
const atom_index: Atom.Index = @intCast(self.atoms.items.len);
const atom = try self.atoms.addOne(allocator);
atom.* = .{
.file = self.index,
.atom_index = atom_index,
.extra = try self.addAtomExtra(allocator, .{}),
};
return atom_index;
}
pub fn getAtom(self: *InternalObject, atom_index: Atom.Index) ?*Atom {
if (atom_index == 0) return null;
assert(atom_index < self.atoms.items.len);
return &self.atoms.items[atom_index];
}
pub fn getAtoms(self: InternalObject) []const Atom.Index {
return self.atoms_indexes.items;
}
fn addAtomExtra(self: *InternalObject, allocator: Allocator, extra: Atom.Extra) !u32 {
const fields = @typeInfo(Atom.Extra).@"struct".fields;
try self.atoms_extra.ensureUnusedCapacity(allocator, fields.len);
return self.addAtomExtraAssumeCapacity(extra);
}
fn addAtomExtraAssumeCapacity(self: *InternalObject, extra: Atom.Extra) u32 {
const index = @as(u32, @intCast(self.atoms_extra.items.len));
const fields = @typeInfo(Atom.Extra).@"struct".fields;
inline for (fields) |field| {
self.atoms_extra.appendAssumeCapacity(switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
});
}
return index;
}
pub fn getAtomExtra(self: InternalObject, index: u32) Atom.Extra {
const fields = @typeInfo(Atom.Extra).@"struct".fields;
var i: usize = index;
var result: Atom.Extra = undefined;
inline for (fields) |field| {
@field(result, field.name) = switch (field.type) {
u32 => self.atoms_extra.items[i],
else => @compileError("bad field type"),
};
i += 1;
}
return result;
}
pub fn setAtomExtra(self: *InternalObject, index: u32, extra: Atom.Extra) void {
assert(index > 0);
const fields = @typeInfo(Atom.Extra).@"struct".fields;
inline for (fields, 0..) |field, i| {
self.atoms_extra.items[index + i] = switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
};
}
}
pub fn getEntryRef(self: InternalObject, macho_file: *MachO) ?MachO.Ref {
const index = self.entry_index orelse return null;
return self.getSymbolRef(index, macho_file);
}
pub fn getDyldStubBinderRef(self: InternalObject, macho_file: *MachO) ?MachO.Ref {
const index = self.dyld_stub_binder_index orelse return null;
return self.getSymbolRef(index, macho_file);
}
pub fn getDyldPrivateRef(self: InternalObject, macho_file: *MachO) ?MachO.Ref {
const index = self.dyld_private_index orelse return null;
return self.getSymbolRef(index, macho_file);
}
pub fn getObjcMsgSendRef(self: InternalObject, macho_file: *MachO) ?MachO.Ref {
const index = self.objc_msg_send_index orelse return null;
return self.getSymbolRef(index, macho_file);
}
pub fn addSymbol(self: *InternalObject, allocator: Allocator) !Symbol.Index {
try self.symbols.ensureUnusedCapacity(allocator, 1);
return self.addSymbolAssumeCapacity();
}
pub fn addSymbolAssumeCapacity(self: *InternalObject) Symbol.Index {
const index: Symbol.Index = @intCast(self.symbols.items.len);
const symbol = self.symbols.addOneAssumeCapacity();
symbol.* = .{ .file = self.index };
return index;
}
pub fn getSymbolRef(self: InternalObject, index: Symbol.Index, macho_file: *MachO) MachO.Ref {
const global_index = self.globals.items[index];
if (macho_file.resolver.get(global_index)) |ref| return ref;
return .{ .index = index, .file = self.index };
}
pub fn addSymbolExtra(self: *InternalObject, allocator: Allocator, extra: Symbol.Extra) !u32 {
const fields = @typeInfo(Symbol.Extra).@"struct".fields;
try self.symbols_extra.ensureUnusedCapacity(allocator, fields.len);
return self.addSymbolExtraAssumeCapacity(extra);
}
fn addSymbolExtraAssumeCapacity(self: *InternalObject, extra: Symbol.Extra) u32 {
const index = @as(u32, @intCast(self.symbols_extra.items.len));
const fields = @typeInfo(Symbol.Extra).@"struct".fields;
inline for (fields) |field| {
self.symbols_extra.appendAssumeCapacity(switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
});
}
return index;
}
pub fn getSymbolExtra(self: InternalObject, index: u32) Symbol.Extra {
const fields = @typeInfo(Symbol.Extra).@"struct".fields;
var i: usize = index;
var result: Symbol.Extra = undefined;
inline for (fields) |field| {
@field(result, field.name) = switch (field.type) {
u32 => self.symbols_extra.items[i],
else => @compileError("bad field type"),
};
i += 1;
}
return result;
}
pub fn setSymbolExtra(self: *InternalObject, index: u32, extra: Symbol.Extra) void {
const fields = @typeInfo(Symbol.Extra).@"struct".fields;
inline for (fields, 0..) |field, i| {
self.symbols_extra.items[index + i] = switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
};
}
}
fn needsObjcMsgsendSymbol(self: InternalObject) bool {
for (self.sections.items(.extra)) |extra| {
if (extra.is_objc_methname or extra.is_objc_selref) return true;
}
return false;
}
const Format = struct {
self: *InternalObject,
macho_file: *MachO,
fn atoms(f: Format, w: *Writer) Writer.Error!void {
try w.writeAll(" atoms\n");
for (f.self.getAtoms()) |atom_index| {
const atom = f.self.getAtom(atom_index) orelse continue;
try w.print(" {f}\n", .{atom.fmt(f.macho_file)});
}
}
fn symtab(f: Format, w: *Writer) Writer.Error!void {
const macho_file = f.macho_file;
const self = f.self;
try w.writeAll(" symbols\n");
for (self.symbols.items, 0..) |sym, i| {
const ref = self.getSymbolRef(@intCast(i), macho_file);
if (ref.getFile(macho_file) == null) {
// TODO any better way of handling this?
try w.print(" {s} : unclaimed\n", .{sym.getName(macho_file)});
} else {
try w.print(" {f}\n", .{ref.getSymbol(macho_file).?.fmt(macho_file)});
}
}
}
};
pub fn fmtAtoms(self: *InternalObject, macho_file: *MachO) std.fmt.Formatter(Format, Format.atoms) {
return .{ .data = .{
.self = self,
.macho_file = macho_file,
} };
}
pub fn fmtSymtab(self: *InternalObject, macho_file: *MachO) std.fmt.Formatter(Format, Format.symtab) {
return .{ .data = .{
.self = self,
.macho_file = macho_file,
} };
}
const Section = struct {
header: macho.section_64,
relocs: std.ArrayListUnmanaged(Relocation) = .empty,
extra: Extra = .{},
const Extra = packed struct {
is_objc_methname: bool = false,
is_objc_selref: bool = false,
};
};
const assert = std.debug.assert;
const macho = std.macho;
const mem = std.mem;
const std = @import("std");
const trace = @import("../../tracy.zig").trace;
const Writer = std.io.Writer;
const Allocator = std.mem.Allocator;
const Atom = @import("Atom.zig");
const File = @import("file.zig").File;
const InternalObject = @This();
const MachO = @import("../MachO.zig");
const Object = @import("Object.zig");
const Relocation = @import("Relocation.zig");
const Symbol = @import("Symbol.zig");