Commit 643b4898f5
Changed files (1)
src
link
src/link/MachO.zig
@@ -1597,7 +1597,7 @@ pub fn populateMissingMetadata(self: *MachO) !void {
};
const stub_size: u4 = switch (self.base.options.target.cpu.arch) {
.x86_64 => 6,
- .aarch64 => 2 * @sizeOf(u32),
+ .aarch64 => 3 * @sizeOf(u32),
else => unreachable, // unhandled architecture type
};
const flags = macho.S_SYMBOL_STUBS | macho.S_ATTR_PURE_INSTRUCTIONS | macho.S_ATTR_SOME_INSTRUCTIONS;
@@ -2525,9 +2525,12 @@ fn writeStub(self: *MachO, index: u32) !void {
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);
@@ -2539,12 +2542,50 @@ fn writeStub(self: *MachO, index: u32) !void {
},
.aarch64 => {
assert(la_ptr_addr >= stub_addr);
- const displacement = try math.divExact(u64, la_ptr_addr - stub_addr, 4);
- const literal = try math.cast(u19, displacement);
- mem.writeIntLittle(u32, code[0..4], aarch64.Instruction.ldr(.x16, .{
- .literal = literal,
- }).toU32());
- mem.writeIntLittle(u32, code[4..8], aarch64.Instruction.br(.x16).toU32());
+ 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,
}