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macho: collect rebase data by scanning atoms directly in objects

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This commit is contained in:
Jakub Konka 2023-08-25 07:09:07 +02:00
parent bf5c35145d
commit 7c11355556
1 changed files with 60 additions and 74 deletions
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134
src/link/MachO/zld.zig
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@ -1368,85 +1368,71 @@ pub const Zld = struct {
}
// Finally, unpack the rest.
const slice = self.sections.slice();
for (slice.items(.header), 0..) |header, sect_id| {
switch (header.type()) {
macho.S_LITERAL_POINTERS,
macho.S_REGULAR,
macho.S_MOD_INIT_FUNC_POINTERS,
macho.S_MOD_TERM_FUNC_POINTERS,
=> {},
else => continue,
}
const segment_index = slice.items(.segment_index)[sect_id];
const segment = self.getSegment(@as(u8, @intCast(sect_id)));
if (segment.maxprot & macho.PROT.WRITE == 0) continue;
log.debug("{s},{s}", .{ header.segName(), header.sectName() });
const cpu_arch = self.options.target.cpu.arch;
var atom_index = slice.items(.first_atom_index)[sect_id] orelse continue;
while (true) {
const cpu_arch = self.options.target.cpu.arch;
for (self.objects.items) |*object| {
for (object.atoms.items) |atom_index| {
const atom = self.getAtom(atom_index);
const sym = self.getSymbol(atom.getSymbolWithLoc());
if (sym.n_desc == MachO.N_DEAD) continue;
const should_rebase = blk: {
if (atom_index == self.dyld_private_atom_index.?) break :blk false;
break :blk !sym.undf();
};
if (should_rebase) {
log.debug(" ATOM({d}, %{d}, '{s}')", .{
atom_index,
atom.sym_index,
self.getSymbolName(atom.getSymbolWithLoc()),
});
const code = Atom.getAtomCode(self, atom_index);
const relocs = Atom.getAtomRelocs(self, atom_index);
const ctx = Atom.getRelocContext(self, atom_index);
for (relocs) |rel| {
switch (cpu_arch) {
.aarch64 => {
const rel_type = @as(macho.reloc_type_arm64, @enumFromInt(rel.r_type));
if (rel_type != .ARM64_RELOC_UNSIGNED) continue;
if (rel.r_length != 3) continue;
},
.x86_64 => {
const rel_type = @as(macho.reloc_type_x86_64, @enumFromInt(rel.r_type));
if (rel_type != .X86_64_RELOC_UNSIGNED) continue;
if (rel.r_length != 3) continue;
},
else => unreachable,
}
const target = Atom.parseRelocTarget(self, .{
.object_id = atom.getFile().?,
.rel = rel,
.code = code,
.base_offset = ctx.base_offset,
.base_addr = ctx.base_addr,
});
const target_sym = self.getSymbol(target);
if (target_sym.undf()) continue;
const base_offset = @as(i32, @intCast(sym.n_value - segment.vmaddr));
const rel_offset = rel.r_address - ctx.base_offset;
const offset = @as(u64, @intCast(base_offset + rel_offset));
log.debug(" | rebase at {x}", .{offset});
try rebase.entries.append(self.gpa, .{
.offset = offset,
.segment_id = segment_index,
});
}
const sect_id = sym.n_sect - 1;
const section = self.sections.items(.header)[sect_id];
const segment_id = self.sections.items(.segment_index)[sect_id];
const segment = self.segments.items[segment_id];
if (segment.maxprot & macho.PROT.WRITE == 0) continue;
switch (section.type()) {
macho.S_LITERAL_POINTERS,
macho.S_REGULAR,
macho.S_MOD_INIT_FUNC_POINTERS,
macho.S_MOD_TERM_FUNC_POINTERS,
=> {},
else => continue,
}
if (atom.next_index) |next_index| {
atom_index = next_index;
} else break;
log.debug(" ATOM({d}, %{d}, '{s}')", .{
atom_index,
atom.sym_index,
self.getSymbolName(atom.getSymbolWithLoc()),
});
const code = Atom.getAtomCode(self, atom_index);
const relocs = Atom.getAtomRelocs(self, atom_index);
const ctx = Atom.getRelocContext(self, atom_index);
for (relocs) |rel| {
switch (cpu_arch) {
.aarch64 => {
const rel_type = @as(macho.reloc_type_arm64, @enumFromInt(rel.r_type));
if (rel_type != .ARM64_RELOC_UNSIGNED) continue;
if (rel.r_length != 3) continue;
},
.x86_64 => {
const rel_type = @as(macho.reloc_type_x86_64, @enumFromInt(rel.r_type));
if (rel_type != .X86_64_RELOC_UNSIGNED) continue;
if (rel.r_length != 3) continue;
},
else => unreachable,
}
const target = Atom.parseRelocTarget(self, .{
.object_id = atom.getFile().?,
.rel = rel,
.code = code,
.base_offset = ctx.base_offset,
.base_addr = ctx.base_addr,
});
const target_sym = self.getSymbol(target);
if (target_sym.undf()) continue;
const base_offset = @as(i32, @intCast(sym.n_value - segment.vmaddr));
const rel_offset = rel.r_address - ctx.base_offset;
const offset = @as(u64, @intCast(base_offset + rel_offset));
log.debug(" | rebase at {x}", .{offset});
try rebase.entries.append(self.gpa, .{
.offset = offset,
.segment_id = segment_id,
});
}
}
}