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macho: refactor tracking of referenced dylibs

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Now, index in the global referenced array hashmap is equivalent to
the dylib's ordinal in the final linked image.
This commit is contained in:
Jakub Konka 2021-08-02 17:40:39 +02:00
parent 159cd528b1
commit f3b328ee8c
2 changed files with 38 additions and 36 deletions
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72
src/link/MachO.zig
View File

@ -63,9 +63,9 @@ entry_addr: ?u64 = null,
objects: std.ArrayListUnmanaged(Object) = .{},
archives: std.ArrayListUnmanaged(Archive) = .{},
dylibs: std.ArrayListUnmanaged(Dylib) = .{},
next_dylib_ordinal: u16 = 1,
dylibs: std.ArrayListUnmanaged(Dylib) = .{},
referenced_dylibs: std.AutoArrayHashMapUnmanaged(u16, void) = .{},
load_commands: std.ArrayListUnmanaged(LoadCommand) = .{},
@ -929,6 +929,17 @@ fn linkWithZld(self: *MachO, comp: *Compilation) !void {
else => unreachable,
};
// TODO mimicking insertion of null symbol from incremental linker.
// This will need to moved.
try self.locals.append(self.base.allocator, .{
.n_strx = 0,
.n_type = macho.N_UNDF,
.n_sect = 0,
.n_desc = 0,
.n_value = 0,
});
try self.strtab.append(self.base.allocator, 0);
// Initialize section ordinals with null ordinal pointing at
// PAGEZERO segment.
try self.section_ordinals.append(self.base.allocator, .{
@ -958,7 +969,8 @@ fn linkWithZld(self: *MachO, comp: *Compilation) !void {
}
try self.sortSections();
try self.addRpaths(rpaths.items);
try self.addRpathLCs(rpaths.items);
try self.addLoadDylibLCs();
try self.addDataInCodeLC();
try self.addCodeSignatureLC();
try self.allocateTextSegment();
@ -2196,17 +2208,6 @@ fn resolveSymbolsInObject(self: *MachO, object_id: u16) !void {
}
fn resolveSymbols(self: *MachO) !void {
// TODO mimicking insertion of null symbol from incremental linker.
// This will need to moved.
try self.locals.append(self.base.allocator, .{
.n_strx = 0,
.n_type = macho.N_UNDF,
.n_sect = 0,
.n_desc = 0,
.n_value = 0,
});
try self.strtab.append(self.base.allocator, 0);
// First pass, resolve symbols in provided objects.
for (self.objects.items) |_, object_id| {
try self.resolveSymbolsInObject(@intCast(u16, object_id));
@ -2335,9 +2336,6 @@ fn resolveSymbols(self: *MachO) !void {
});
}
var referenced = std.AutoHashMap(u16, void).init(self.base.allocator);
defer referenced.deinit();
loop: for (self.undefs.items) |sym| {
if (symbolIsNull(sym)) continue;
@ -2345,23 +2343,12 @@ fn resolveSymbols(self: *MachO) !void {
for (self.dylibs.items) |*dylib, id| {
if (!dylib.symbols.contains(sym_name)) continue;
if (!referenced.contains(@intCast(u16, id))) {
// Add LC_LOAD_DYLIB load command for each referenced dylib/stub.
dylib.ordinal = self.next_dylib_ordinal;
const dylib_id = dylib.id orelse unreachable;
var dylib_cmd = try commands.createLoadDylibCommand(
self.base.allocator,
dylib_id.name,
dylib_id.timestamp,
dylib_id.current_version,
dylib_id.compatibility_version,
);
errdefer dylib_cmd.deinit(self.base.allocator);
try self.load_commands.append(self.base.allocator, .{ .Dylib = dylib_cmd });
self.next_dylib_ordinal += 1;
try referenced.putNoClobber(@intCast(u16, id), {});
const dylib_id = @intCast(u16, id);
if (!self.referenced_dylibs.contains(dylib_id)) {
try self.referenced_dylibs.putNoClobber(self.base.allocator, dylib_id, {});
}
const ordinal = self.referenced_dylibs.getIndex(dylib_id) orelse unreachable;
const resolv = self.symbol_resolver.getPtr(sym.n_strx) orelse unreachable;
const undef = &self.undefs.items[resolv.where_index];
const import_sym_index = @intCast(u32, self.imports.items.len);
@ -2369,7 +2356,7 @@ fn resolveSymbols(self: *MachO) !void {
.n_strx = undef.n_strx,
.n_type = macho.N_UNDF | macho.N_EXT,
.n_sect = 0,
.n_desc = packDylibOrdinal(dylib.ordinal.?),
.n_desc = packDylibOrdinal(@intCast(u16, ordinal + 1)),
.n_value = 0,
});
resolv.* = .{
@ -2804,7 +2791,7 @@ fn addCodeSignatureLC(self: *MachO) !void {
}
}
fn addRpaths(self: *MachO, rpaths: []const []const u8) !void {
fn addRpathLCs(self: *MachO, rpaths: []const []const u8) !void {
for (rpaths) |rpath| {
const cmdsize = @intCast(u32, mem.alignForwardGeneric(
u64,
@ -2823,6 +2810,22 @@ fn addRpaths(self: *MachO, rpaths: []const []const u8) !void {
}
}
fn addLoadDylibLCs(self: *MachO) !void {
for (self.referenced_dylibs.keys()) |id| {
const dylib = self.dylibs.items[id];
const dylib_id = dylib.id orelse unreachable;
var dylib_cmd = try commands.createLoadDylibCommand(
self.base.allocator,
dylib_id.name,
dylib_id.timestamp,
dylib_id.current_version,
dylib_id.compatibility_version,
);
errdefer dylib_cmd.deinit(self.base.allocator);
try self.load_commands.append(self.base.allocator, .{ .Dylib = dylib_cmd });
}
}
fn flushZld(self: *MachO) !void {
self.load_commands_dirty = true;
try self.writeTextBlocks();
@ -3353,6 +3356,7 @@ pub fn deinit(self: *MachO) void {
dylib.deinit(self.base.allocator);
}
self.dylibs.deinit(self.base.allocator);
self.referenced_dylibs.deinit(self.base.allocator);
for (self.load_commands.items) |*lc| {
lc.deinit(self.base.allocator);

2
src/link/MachO/Dylib.zig
View File

@ -22,8 +22,6 @@ name: []const u8,
header: ?macho.mach_header_64 = null,
ordinal: ?u16 = null,
// The actual dylib contents we care about linking with will be embedded at
// an offset within a file if we are linking against a fat lib
library_offset: u64 = 0,