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macho+zld: refactor how we resolve dyld_stub_binder symbol

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This commit is contained in:
Jakub Konka 2023-04-04 09:32:26 +02:00
parent 49b56f88b9
commit 3a8362e751
1 changed files with 18 additions and 45 deletions
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63
src/link/MachO/zld.zig
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@ -590,9 +590,9 @@ pub const Zld = struct {
}
fn createDyldStubBinderGotAtom(self: *Zld) !void {
const sym_index = self.dyld_stub_binder_index orelse return;
const gpa = self.gpa;
const target = SymbolWithLoc{ .sym_index = sym_index };
const global_index = self.dyld_stub_binder_index orelse return;
const target = self.globals.items[global_index];
const atom_index = try self.createGotAtom();
const got_index = @intCast(u32, self.got_entries.items.len);
try self.got_entries.append(gpa, .{
@ -661,7 +661,8 @@ pub const Zld = struct {
break :blk sym.n_value;
};
const dyld_stub_binder_got_addr = blk: {
const index = self.got_table.get(.{ .sym_index = self.dyld_stub_binder_index.? }).?;
const sym_loc = self.globals.items[self.dyld_stub_binder_index.?];
const index = self.got_table.get(sym_loc).?;
const entry = self.got_entries.items[index];
break :blk entry.getAtomSymbol(self).n_value;
};
@ -932,12 +933,12 @@ pub const Zld = struct {
}
}
fn forceSymbolDefined(self: *Zld, name: []const u8, resolver: *SymbolResolver) !void {
fn addUndefined(self: *Zld, name: []const u8, resolver: *SymbolResolver) !void {
const sym_index = try self.allocateSymbol();
const sym_loc = SymbolWithLoc{ .sym_index = sym_index };
const sym = self.getSymbolPtr(sym_loc);
sym.n_strx = try self.strtab.insert(self.gpa, name);
sym.n_type = macho.N_UNDF | macho.N_EXT;
sym.n_type = macho.N_UNDF;
const global_index = try self.addGlobal(sym_loc);
try resolver.table.putNoClobber(name, global_index);
try resolver.unresolved.putNoClobber(global_index, {});
@ -949,12 +950,12 @@ pub const Zld = struct {
// on the linker line.
if (self.options.output_mode == .Exe) {
const entry_name = self.options.entry orelse load_commands.default_entry_point;
try self.forceSymbolDefined(entry_name, resolver);
try self.addUndefined(entry_name, resolver);
}
// Force resolution of any symbols requested by the user.
for (self.options.force_undefined_symbols.keys()) |sym_name| {
try self.forceSymbolDefined(sym_name, resolver);
try self.addUndefined(sym_name, resolver);
}
for (self.objects.items, 0..) |_, object_id| {
@ -962,8 +963,17 @@ pub const Zld = struct {
}
try self.resolveSymbolsInArchives(resolver);
try self.resolveDyldStubBinder(resolver);
// Finally, force resolution of dyld_stub_binder if there are imports
// requested.
if (resolver.unresolved.count() > 0) {
try self.addUndefined("dyld_stub_binder", resolver);
}
try self.resolveSymbolsInDylibs(resolver);
self.dyld_stub_binder_index = resolver.table.get("dyld_stub_binder");
try self.createMhExecuteHeaderSymbol(resolver);
try self.createDsoHandleSymbol(resolver);
try self.resolveSymbolsAtLoading(resolver);
@ -1241,43 +1251,6 @@ pub const Zld = struct {
global.* = sym_loc;
}
fn resolveDyldStubBinder(self: *Zld, resolver: *SymbolResolver) !void {
if (self.dyld_stub_binder_index != null) return;
if (resolver.unresolved.count() == 0) return; // no need for a stub binder if we don't have any imports
const gpa = self.gpa;
const sym_name = "dyld_stub_binder";
const sym_index = try self.allocateSymbol();
const sym_loc = SymbolWithLoc{ .sym_index = sym_index };
const sym = self.getSymbolPtr(sym_loc);
sym.n_strx = try self.strtab.insert(gpa, sym_name);
sym.n_type = macho.N_UNDF;
const global = SymbolWithLoc{ .sym_index = sym_index };
try self.globals.append(gpa, global);
for (self.dylibs.items, 0..) |dylib, id| {
if (!dylib.symbols.contains(sym_name)) continue;
const dylib_id = @intCast(u16, id);
if (!self.referenced_dylibs.contains(dylib_id)) {
try self.referenced_dylibs.putNoClobber(gpa, dylib_id, {});
}
const ordinal = self.referenced_dylibs.getIndex(dylib_id) orelse unreachable;
sym.n_type |= macho.N_EXT;
sym.n_desc = @intCast(u16, ordinal + 1) * macho.N_SYMBOL_RESOLVER;
self.dyld_stub_binder_index = sym_index;
break;
}
if (self.dyld_stub_binder_index == null) {
log.err("undefined reference to symbol '{s}'", .{sym_name});
return error.UndefinedSymbolReference;
}
}
pub fn deinit(self: *Zld) void {
const gpa = self.gpa;