motiejus/zig
1
Fork 0
Code Releases Activity

plan9 linker: use a global offset table

Browse Source 
this simplifies stuff and makes us not have to use relocations
This commit is contained in:
Jacob G-W
2021-06-13 21:29:32 -04:00
committed by Andrew Kelley
parent 166dffb088
commit db2d5b49c6
3 changed files with 104 additions and 87 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/codegen.zig
View File

@@ -2593,14 +2593,15 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
}
if (inst.func.value()) |func_value| {
if (func_value.castTag(.function)) |func_payload| {
try self.genSetReg(inst.base.src, Type.initTag(.u64), .rax, .{ .immediate = 0xdeadbeefdeadbeef });
try p9.addCallReloc(self.code, .{
.caller = p9.cur_decl,
.callee = func_payload.data.owner_decl,
.offset_in_caller = self.code.items.len,
});
// call rax
try self.code.appendSlice(&.{ 0xff, 0xd0 });
const ptr_bits = self.target.cpu.arch.ptrBitWidth();
const ptr_bytes: u64 = @divExact(ptr_bits, 8);
const got_addr = p9.bases.data;
const got_index = func_payload.data.owner_decl.link.plan9.got_index.?;
// ff 14 25 xx xx xx xx call [addr]
try self.code.ensureCapacity(self.code.items.len + 7);
self.code.appendSliceAssumeCapacity(&[3]u8{ 0xff, 0x14, 0x25 });
const fn_got_addr = got_addr + got_index * ptr_bytes;
mem.writeIntLittle(u32, self.code.addManyAsArrayAssumeCapacity(4), @intCast(u32, fn_got_addr));
} else return self.fail(inst.base.src, "TODO implement calling extern fn on plan9", .{});
} else {
return self.fail(inst.base.src, "TODO implement calling runtime known function pointer", .{});
@@ -4273,6 +4274,10 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
const decl = payload.data;
const got_addr = coff_file.offset_table_virtual_address + decl.link.coff.offset_table_index * ptr_bytes;
return MCValue{ .memory = got_addr };
} else if (self.bin_file.cast(link.File.Plan9)) |p9| {
const decl = payload.data;
const got_addr = p9.bases.data + decl.link.plan9.got_index.? * ptr_bytes;
return MCValue{ .memory = got_addr };
} else {
return self.fail(src, "TODO codegen non-ELF const Decl pointer", .{});
}