Commit 91c0552cfc
Changed files (1)
src
link
src/link/MachO.zig
@@ -808,17 +808,23 @@ pub fn flush(self: *MachO, comp: *Compilation) !void {
sect.size -= atom.size;
}
for (self.stubs.items) |_| {
- const stub_atom = try self.createStubHelperAtom();
- try self.allocateAtomStage1(stub_atom, .{
+ const stub_helper_atom = try self.createStubHelperAtom();
+ try self.allocateAtomStage1(stub_helper_atom, .{
.seg = self.text_segment_cmd_index.?,
.sect = self.stub_helper_section_index.?,
});
- const laptr_atom = try self.createLazyPointerAtom(stub_atom.local_sym_index);
+ const laptr_atom = try self.createLazyPointerAtom(stub_helper_atom.local_sym_index);
try self.allocateAtomStage1(laptr_atom, .{
.seg = self.data_segment_cmd_index.?,
.sect = self.la_symbol_ptr_section_index.?,
});
+
+ const stub_atom = try self.createStubAtom(laptr_atom.local_sym_index);
+ try self.allocateAtomStage1(stub_atom, .{
+ .seg = self.text_segment_cmd_index.?,
+ .sect = self.stubs_section_index.?,
+ });
}
try self.allocateTextSegment();
try self.allocateDataConstSegment();
@@ -1715,16 +1721,10 @@ fn sortSections(self: *MachO) !void {
fn allocateTextSegment(self: *MachO) !void {
const seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment;
- const nstubs = @intCast(u32, self.stubs.items.len);
-
const base_vmaddr = self.load_commands.items[self.pagezero_segment_cmd_index.?].Segment.inner.vmsize;
seg.inner.fileoff = 0;
seg.inner.vmaddr = base_vmaddr;
- // Set stubs sizes
- const stubs = &seg.sections.items[self.stubs_section_index.?];
- stubs.size += nstubs * stubs.reserved2;
-
var sizeofcmds: u64 = 0;
for (self.load_commands.items) |lc| {
sizeofcmds += lc.cmdsize();
@@ -2274,6 +2274,86 @@ fn createLazyPointerAtom(self: *MachO, stub_sym_index: u32) !*TextBlock {
return atom;
}
+fn createStubAtom(self: *MachO, laptr_sym_index: u32) !*TextBlock {
+ const arch = self.base.options.target.cpu.arch;
+ const alignment: u2 = switch (arch) {
+ .x86_64 => 0,
+ .aarch64 => 2,
+ else => unreachable, // unhandled architecture type
+ };
+ const stub_size: u4 = switch (arch) {
+ .x86_64 => 6,
+ .aarch64 => 3 * @sizeOf(u32),
+ else => unreachable, // unhandled architecture type
+ };
+ const local_sym_index = @intCast(u32, self.locals.items.len);
+ try self.locals.append(self.base.allocator, .{
+ .n_strx = try self.makeString("stub"),
+ .n_type = macho.N_SECT,
+ .n_sect = 0,
+ .n_desc = 0,
+ .n_value = 0,
+ });
+ const atom = try self.createEmptyAtom(.{
+ .seg = self.text_segment_cmd_index.?,
+ .sect = self.stubs_section_index.?,
+ }, local_sym_index, stub_size, alignment);
+ switch (arch) {
+ .x86_64 => {
+ // jmp
+ atom.code.items[0] = 0xff;
+ atom.code.items[1] = 0x25;
+ try atom.relocs.append(self.base.allocator, .{
+ .offset = 2,
+ .where = .local,
+ .where_index = laptr_sym_index,
+ .payload = .{
+ .branch = .{ .arch = arch },
+ },
+ });
+ },
+ .aarch64 => {
+ try atom.relocs.ensureTotalCapacity(self.base.allocator, 2);
+ // adrp x16, pages
+ mem.writeIntLittle(u32, atom.code.items[0..4], aarch64.Instruction.adrp(.x16, 0).toU32());
+ atom.relocs.appendAssumeCapacity(.{
+ .offset = 0,
+ .where = .local,
+ .where_index = laptr_sym_index,
+ .payload = .{
+ .page = .{
+ .kind = .page,
+ .addend = 0,
+ },
+ },
+ });
+ // ldr x16, x16, offset
+ mem.writeIntLittle(u32, atom.code.items[4..8], aarch64.Instruction.ldr(.x16, .{
+ .register = .{
+ .rn = .x16,
+ .offset = aarch64.Instruction.LoadStoreOffset.imm(0),
+ },
+ }).toU32());
+ atom.relocs.appendAssumeCapacity(.{
+ .offset = 4,
+ .where = .local,
+ .where_index = laptr_sym_index,
+ .payload = .{
+ .page_off = .{
+ .kind = .page,
+ .addend = 0,
+ .op_kind = .load,
+ },
+ },
+ });
+ // br x16
+ mem.writeIntLittle(u32, atom.code.items[8..12], aarch64.Instruction.br(.x16).toU32());
+ },
+ else => unreachable,
+ }
+ return atom;
+}
+
fn resolveSymbolsInObject(
self: *MachO,
object_id: u16,
@@ -2761,12 +2841,6 @@ fn addLoadDylibLCs(self: *MachO) !void {
fn flushZld(self: *MachO) !void {
try self.writeTextBlocks();
- for (self.stubs.items) |_, i| {
- const index = @intCast(u32, i);
- // TODO weak bound pointers
- try self.writeStub(index);
- }
-
if (self.common_section_index) |index| {
const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
const sect = &seg.sections.items[index];
@@ -4665,82 +4739,6 @@ fn writeGotEntry(self: *MachO, index: usize) !void {
try self.base.file.?.pwriteAll(mem.asBytes(&sym.n_value), off);
}
-fn writeStub(self: *MachO, index: u32) !void {
- const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment;
- const stubs = text_segment.sections.items[self.stubs_section_index.?];
- const data_segment = self.load_commands.items[self.data_segment_cmd_index.?].Segment;
- const la_symbol_ptr = data_segment.sections.items[self.la_symbol_ptr_section_index.?];
-
- const stub_off = stubs.offset + index * stubs.reserved2;
- const stub_addr = stubs.addr + index * stubs.reserved2;
- const la_ptr_addr = la_symbol_ptr.addr + index * @sizeOf(u64);
-
- log.debug("writing stub at 0x{x}", .{stub_off});
-
- var code = try self.base.allocator.alloc(u8, stubs.reserved2);
- defer self.base.allocator.free(code);
-
- switch (self.base.options.target.cpu.arch) {
- .x86_64 => {
- assert(la_ptr_addr >= stub_addr + stubs.reserved2);
- const displacement = try math.cast(u32, la_ptr_addr - stub_addr - stubs.reserved2);
- // jmp
- code[0] = 0xff;
- code[1] = 0x25;
- mem.writeIntLittle(u32, code[2..][0..4], displacement);
- },
- .aarch64 => {
- assert(la_ptr_addr >= stub_addr);
- outer: {
- const this_addr = stub_addr;
- const target_addr = la_ptr_addr;
- inner: {
- const displacement = math.divExact(u64, target_addr - this_addr, 4) catch break :inner;
- const literal = math.cast(u18, displacement) catch break :inner;
- // ldr x16, literal
- mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.ldr(.x16, .{
- .literal = literal,
- }).toU32());
- // nop
- mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.nop().toU32());
- break :outer;
- }
- inner: {
- const new_this_addr = this_addr + @sizeOf(u32);
- const displacement = math.divExact(u64, target_addr - new_this_addr, 4) catch break :inner;
- const literal = math.cast(u18, displacement) catch break :inner;
- // nop
- mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.nop().toU32());
- // ldr x16, literal
- mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.ldr(.x16, .{
- .literal = literal,
- }).toU32());
- break :outer;
- }
- // Use adrp followed by ldr(register).
- const this_page = @intCast(i32, this_addr >> 12);
- const target_page = @intCast(i32, target_addr >> 12);
- const pages = @intCast(i21, target_page - this_page);
- // adrp x16, pages
- mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.adrp(.x16, pages).toU32());
- const narrowed = @truncate(u12, target_addr);
- const offset = try math.divExact(u12, narrowed, 8);
- // ldr x16, x16, offset
- mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.ldr(.x16, .{
- .register = .{
- .rn = .x16,
- .offset = aarch64.Instruction.LoadStoreOffset.imm(offset),
- },
- }).toU32());
- }
- // br x16
- mem.writeIntLittle(u32, code[8..12], aarch64.Instruction.br(.x16).toU32());
- },
- else => unreachable,
- }
- try self.base.file.?.pwriteAll(code, stub_off);
-}
-
fn relocateSymbolTable(self: *MachO) !void {
const symtab = &self.load_commands.items[self.symtab_cmd_index.?].Symtab;
const nlocals = self.locals.items.len;