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x86_64: emit R_X86_64_GOT32 for non-PIC GOT references

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This commit is contained in:
Jakub Konka 2023-09-26 13:35:50 +02:00
parent 8e1421f19e
commit af40bce08a
5 changed files with 66 additions and 12 deletions
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35
src/arch/x86_64/CodeGen.zig
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@ -8223,11 +8223,14 @@ fn airCall(self: *Self, inst: Air.Inst.Index, modifier: std.builtin.CallModifier
const sym = elf_file.symbol(sym_index);
sym.flags.needs_got = true;
_ = try sym.getOrCreateGotEntry(sym_index, elf_file);
const got_addr = sym.gotAddress(elf_file);
try self.asmMemory(.{ ._, .call }, Memory.sib(.qword, .{
.base = .{ .reg = .ds },
.disp = @intCast(got_addr),
}));
_ = try self.addInst(.{
.tag = .call,
.ops = .direct_got_reloc,
.data = .{ .reloc = .{
.atom_index = try self.owner.getSymbolIndex(self),
.sym_index = sym.esym_index,
} },
});
} else if (self.bin_file.cast(link.File.Coff)) |coff_file| {
const atom = try coff_file.getOrCreateAtomForDecl(owner_decl);
const sym_index = coff_file.getAtom(atom).getSymbolIndex().?;
@ -10290,12 +10293,24 @@ fn genLazySymbolRef(
const sym = elf_file.symbol(sym_index);
sym.flags.needs_got = true;
_ = try sym.getOrCreateGotEntry(sym_index, elf_file);
const got_addr = sym.gotAddress(elf_file);
const got_mem =
Memory.sib(.qword, .{ .base = .{ .reg = .ds }, .disp = @intCast(got_addr) });
const reloc = Mir.Reloc{
.atom_index = try self.owner.getSymbolIndex(self),
.sym_index = sym.esym_index,
};
switch (tag) {
.lea, .mov => try self.asmRegisterMemory(.{ ._, .mov }, reg.to64(), got_mem),
.call => try self.asmMemory(.{ ._, .call }, got_mem),
.lea, .mov => _ = try self.addInst(.{
.tag = .mov,
.ops = .direct_got_reloc,
.data = .{ .rx = .{
.r1 = reg.to64(),
.payload = try self.addExtra(reloc),
} },
}),
.call => _ = try self.addInst(.{
.tag = .call,
.ops = .direct_got_reloc,
.data = .{ .reloc = reloc },
}),
else => unreachable,
}
switch (tag) {

14
src/arch/x86_64/Emit.zig
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@ -80,9 +80,21 @@ pub fn emitMir(emit: *Emit) Error!void {
}),
.linker_got,
.linker_direct,
.linker_direct_got,
.linker_import,
.linker_tlv,
=> |symbol| if (emit.bin_file.cast(link.File.MachO)) |macho_file| {
=> |symbol| if (emit.bin_file.cast(link.File.Elf)) |elf_file| {
const r_type: u32 = switch (lowered_relocs[0].target) {
.linker_direct_got => std.elf.R_X86_64_GOT32,
else => unreachable,
};
const atom_ptr = elf_file.symbol(symbol.atom_index).atom(elf_file).?;
try atom_ptr.addReloc(elf_file, .{
.r_offset = end_offset - 4,
.r_info = (@as(u64, @intCast(symbol.sym_index)) << 32) | r_type,
.r_addend = 0,
});
} else if (emit.bin_file.cast(link.File.MachO)) |macho_file| {
const atom_index = macho_file.getAtomIndexForSymbol(.{ .sym_index = symbol.atom_index }).?;
try link.File.MachO.Atom.addRelocation(macho_file, atom_index, .{
.type = switch (lowered_relocs[0].target) {

23
src/arch/x86_64/Lower.zig
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@ -52,6 +52,7 @@ pub const Reloc = struct {
linker_extern_fn: Mir.Reloc,
linker_got: Mir.Reloc,
linker_direct: Mir.Reloc,
linker_direct_got: Mir.Reloc,
linker_import: Mir.Reloc,
linker_tlv: Mir.Reloc,
};
@ -387,7 +388,7 @@ fn generic(lower: *Lower, inst: Mir.Inst) Error!void {
.rrmi_sib, .rrmi_rip => inst.data.rrix.fixes,
.mi_sib_u, .mi_rip_u, .mi_sib_s, .mi_rip_s => inst.data.x.fixes,
.m_sib, .m_rip, .rax_moffs, .moffs_rax => inst.data.x.fixes,
.extern_fn_reloc, .got_reloc, .direct_reloc, .import_reloc, .tlv_reloc => ._,
.extern_fn_reloc, .got_reloc, .direct_reloc, .direct_got_reloc, .import_reloc, .tlv_reloc => ._,
else => return lower.fail("TODO lower .{s}", .{@tagName(inst.ops)}),
};
try lower.emit(switch (fixes) {
@ -511,6 +512,26 @@ fn generic(lower: *Lower, inst: Mir.Inst) Error!void {
.extern_fn_reloc => &.{
.{ .imm = lower.reloc(.{ .linker_extern_fn = inst.data.reloc }) },
},
.direct_got_reloc => ops: {
switch (inst.tag) {
.call => {
_ = lower.reloc(.{ .linker_direct_got = inst.data.reloc });
break :ops &.{
.{ .mem = Memory.sib(.qword, .{ .base = .{ .reg = .ds }, .disp = 0 }) },
};
},
.mov => {
const reg = inst.data.rx.r1;
const extra = lower.mir.extraData(Mir.Reloc, inst.data.rx.payload).data;
_ = lower.reloc(.{ .linker_direct_got = extra });
break :ops &.{
.{ .reg = reg },
.{ .mem = Memory.sib(.qword, .{ .base = .{ .reg = .ds }, .disp = 0 }) },
};
},
else => unreachable,
}
},
.got_reloc, .direct_reloc, .import_reloc, .tlv_reloc => ops: {
const reg = inst.data.rx.r1;
const extra = lower.mir.extraData(Mir.Reloc, inst.data.rx.payload).data;

3
src/arch/x86_64/Mir.zig
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@ -783,6 +783,9 @@ pub const Inst = struct {
/// Linker relocation - threadlocal variable via GOT indirection.
/// Uses `rx` payload with extra data of type `Reloc`.
tlv_reloc,
/// Linker relocation - non-PIC direct reference to GOT cell.
/// Uses `reloc` payload if tag is `call`, `rx` otherwise.
direct_got_reloc,
// Pseudo instructions:

3
src/link/Elf/Atom.zig
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@ -518,6 +518,9 @@ pub fn resolveRelocs(self: Atom, elf_file: *Elf, code: []u8) !void {
elf.R_X86_64_PC32,
=> try cwriter.writeIntLittle(i32, @as(i32, @intCast(S + A - P))),
elf.R_X86_64_GOT32 => try cwriter.writeIntLittle(u32, @as(u32, @intCast(G + GOT + A))),
elf.R_X86_64_GOT64 => try cwriter.writeIntLittle(u64, @as(u64, @intCast(G + GOT + A))),
elf.R_X86_64_GOTPCREL => try cwriter.writeIntLittle(i32, @as(i32, @intCast(G + GOT + A - P))),
elf.R_X86_64_GOTPC32 => try cwriter.writeIntLittle(i32, @as(i32, @intCast(GOT + A - P))),
elf.R_X86_64_GOTPC64 => try cwriter.writeIntLittle(i64, GOT + A - P),