srctree

Jakub Konka parent 3c5e8407 a7e4d172
link/macho: introduce Atom extras for out-of-band data

inlinesplit
src/link/MachO.zig added: 163, removed: 47, total 116
@@ -65,6 +65,7 @@ entry_index: ?Symbol.Index = null,
 
/// List of atoms that are either synthetic or map directly to the Zig source program.
atoms: std.ArrayListUnmanaged(Atom) = .{},
atoms_extra: std.ArrayListUnmanaged(u32) = .{},
thunks: std.ArrayListUnmanaged(Thunk) = .{},
unwind_records: std.ArrayListUnmanaged(UnwindInfo.Record) = .{},
 
@@ -246,6 +247,7 @@ pub fn createEmpty(
try self.files.append(gpa, .null);
// Atom at index 0 is reserved as null atom
try self.atoms.append(gpa, .{});
try self.atoms_extra.append(gpa, 0);
// Append empty string to string tables
try self.strings.buffer.append(gpa, 0);
try self.strtab.append(gpa, 0);
@@ -350,6 +352,7 @@ pub fn deinit(self: *MachO) void {
self.unwind_info.deinit(gpa);
 
self.atoms.deinit(gpa);
self.atoms_extra.deinit(gpa);
for (self.thunks.items) |*thunk| {
thunk.deinit(gpa);
}
@@ -3865,6 +3868,50 @@ pub fn getAtom(self: *MachO, index: Atom.Index) ?*Atom {
return &self.atoms.items[index];
}
 
pub fn addAtomExtra(self: *MachO, extra: Atom.Extra) !u32 {
const fields = @typeInfo(Atom.Extra).Struct.fields;
try self.atoms_extra.ensureUnusedCapacity(self.base.comp.gpa, fields.len);
return self.addAtomExtraAssumeCapacity(extra);
}
 
pub fn addAtomExtraAssumeCapacity(self: *MachO, extra: Atom.Extra) u32 {
const index = @as(u32, @intCast(self.atoms_extra.items.len));
const fields = @typeInfo(Atom.Extra).Struct.fields;
inline for (fields) |field| {
self.atoms_extra.appendAssumeCapacity(switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
});
}
return index;
}
 
pub fn getAtomExtra(self: *MachO, index: u32) ?Atom.Extra {
if (index == 0) return null;
const fields = @typeInfo(Atom.Extra).Struct.fields;
var i: usize = index;
var result: Atom.Extra = undefined;
inline for (fields) |field| {
@field(result, field.name) = switch (field.type) {
u32 => self.atoms_extra.items[i],
else => @compileError("bad field type"),
};
i += 1;
}
return result;
}
 
pub fn setAtomExtra(self: *MachO, index: u32, extra: Atom.Extra) void {
assert(index > 0);
const fields = @typeInfo(Atom.Extra).Struct.fields;
inline for (fields, 0..) |field, i| {
self.atoms_extra.items[index + i] = switch (field.type) {
u32 => @field(extra, field.name),
else => @compileError("bad field type"),
};
}
}
 
pub fn addSymbol(self: *MachO) !Symbol.Index {
const index = @as(Symbol.Index, @intCast(self.symbols.items.len));
const symbol = try self.symbols.addOne(self.base.comp.gpa);
 
src/link/MachO/Atom.zig added: 163, removed: 47, total 116
@@ -23,18 +23,9 @@ out_n_sect: u8 = 0,
/// off + size <= parent section size.
off: u64 = 0,
 
/// Relocations of this atom.
relocs: Loc = .{},
 
/// Index of this atom in the linker's atoms table.
atom_index: Index = 0,
 
/// Index of the thunk for this atom.
thunk_index: Thunk.Index = 0,
 
/// Unwind records associated with this atom.
unwind_records: Loc = .{},
 
flags: Flags = .{},
 
/// Points to the previous and next neighbors, based on the `text_offset`.
@@ -42,6 +33,8 @@ flags: Flags = .{},
prev_index: Index = 0,
next_index: Index = 0,
 
extra: u32 = 0,
 
pub fn getName(self: Atom, macho_file: *MachO) [:0]const u8 {
return switch (self.getFile(macho_file)) {
.dylib => unreachable,
@@ -67,7 +60,7 @@ pub fn getData(self: Atom, macho_file: *MachO, buffer: []u8) !void {
pub fn getRelocs(self: Atom, macho_file: *MachO) []const Relocation {
return switch (self.getFile(macho_file)) {
.dylib => unreachable,
inline else => |x| x.getAtomRelocs(self),
inline else => |x| x.getAtomRelocs(self, macho_file),
};
}
 
@@ -95,10 +88,11 @@ pub fn getPriority(self: Atom, macho_file: *MachO) u64 {
}
 
pub fn getUnwindRecords(self: Atom, macho_file: *MachO) []const UnwindInfo.Record.Index {
if (!self.flags.unwind) return &[0]UnwindInfo.Record.Index{};
const extra = self.getExtra(macho_file).?;
return switch (self.getFile(macho_file)) {
.dylib => unreachable,
.zig_object, .internal => &[0]UnwindInfo.Record.Index{},
.object => |x| x.unwind_records.items[self.unwind_records.pos..][0..self.unwind_records.len],
.dylib, .zig_object, .internal => unreachable,
.object => |x| x.unwind_records.items[extra.unwind_index..][0..extra.unwind_count],
};
}
 
@@ -114,7 +108,38 @@ pub fn markUnwindRecordsDead(self: Atom, macho_file: *MachO) void {
}
 
pub fn getThunk(self: Atom, macho_file: *MachO) *Thunk {
return macho_file.getThunk(self.thunk_index);
assert(self.flags.thunk);
const extra = self.getExtra(macho_file).?;
return macho_file.getThunk(extra.thunk);
}
 
const AddExtraOpts = struct {
thunk: ?u32 = null,
rel_index: ?u32 = null,
rel_count: ?u32 = null,
unwind_index: ?u32 = null,
unwind_count: ?u32 = null,
};
 
pub fn addExtra(atom: *Atom, opts: AddExtraOpts, macho_file: *MachO) !void {
if (atom.getExtra(macho_file) == null) {
atom.extra = try macho_file.addAtomExtra(.{});
}
var extra = atom.getExtra(macho_file).?;
inline for (@typeInfo(@TypeOf(opts)).Struct.fields) |field| {
if (@field(opts, field.name)) |x| {
@field(extra, field.name) = x;
}
}
atom.setExtra(extra, macho_file);
}
 
pub inline fn getExtra(atom: Atom, macho_file: *MachO) ?Extra {
return macho_file.getAtomExtra(atom.extra);
}
 
pub inline fn setExtra(atom: Atom, extra: Extra, macho_file: *MachO) void {
macho_file.setAtomExtra(atom.extra, extra);
}
 
pub fn initOutputSection(sect: macho.section_64, macho_file: *MachO) !u8 {
@@ -403,14 +428,20 @@ pub fn addReloc(self: *Atom, macho_file: *MachO, reloc: Relocation) !void {
const gpa = macho_file.base.comp.gpa;
const file = self.getFile(macho_file);
assert(file == .zig_object);
const rels = &file.zig_object.relocs.items[self.relocs.pos];
assert(self.flags.relocs);
var extra = self.getExtra(macho_file).?;
const rels = &file.zig_object.relocs.items[extra.rel_index];
try rels.append(gpa, reloc);
self.relocs.len += 1;
extra.rel_count += 1;
self.setExtra(extra, macho_file);
}
 
pub fn freeRelocs(self: *Atom, macho_file: *MachO) void {
self.getFile(macho_file).zig_object.freeAtomRelocs(self.*);
self.relocs.len = 0;
if (!self.flags.relocs) return;
self.getFile(macho_file).zig_object.freeAtomRelocs(self.*, macho_file);
var extra = self.getExtra(macho_file).?;
extra.rel_count = 0;
self.setExtra(extra, macho_file);
}
 
pub fn scanRelocs(self: Atom, macho_file: *MachO) !void {
@@ -1117,19 +1148,21 @@ fn format2(
_ = unused_fmt_string;
const atom = ctx.atom;
const macho_file = ctx.macho_file;
try writer.print("atom({d}) : {s} : @{x} : sect({d}) : align({x}) : size({x}) : nreloc({d}) : thunk({d})", .{
try writer.print("atom({d}) : {s} : @{x} : sect({d}) : align({x}) : size({x}) : nreloc({d})", .{
atom.atom_index, atom.getName(macho_file), atom.getAddress(macho_file),
atom.out_n_sect, atom.alignment, atom.size,
atom.getRelocs(macho_file).len, atom.thunk_index,
atom.getRelocs(macho_file).len,
});
if (atom.flags.thunk) try writer.print(" : thunk({d})", .{atom.getExtra(macho_file).?.thunk});
if (!atom.flags.alive) try writer.writeAll(" : [*]");
if (atom.unwind_records.len > 0) {
if (atom.flags.unwind) {
try writer.writeAll(" : unwind{ ");
for (atom.getUnwindRecords(macho_file), atom.unwind_records.pos..) |index, i| {
const extra = atom.getExtra(macho_file).?;
for (atom.getUnwindRecords(macho_file), extra.unwind_index..) |index, i| {
const rec = macho_file.getUnwindRecord(index);
try writer.print("{d}", .{index});
if (!rec.alive) try writer.writeAll("([*])");
if (i < atom.unwind_records.pos + atom.unwind_records.len - 1) try writer.writeAll(", ");
if (i < extra.unwind_index + extra.unwind_count - 1) try writer.writeAll(", ");
}
try writer.writeAll(" }");
}
@@ -1143,11 +1176,32 @@ pub const Flags = packed struct {
 
/// Specifies if the atom has been visited during garbage collection.
visited: bool = false,
 
/// Whether this atom has a range extension thunk.
thunk: bool = false,
 
/// Whether this atom has any relocations.
relocs: bool = false,
 
/// Whether this atom has any unwind records.
unwind: bool = false,
};
 
pub const Loc = struct {
pos: u32 = 0,
len: u32 = 0,
pub const Extra = struct {
/// Index of the range extension thunk of this atom.
thunk: u32 = 0,
 
/// Start index of relocations belonging to this atom.
rel_index: u32 = 0,
 
/// Count of relocations belonging to this atom.
rel_count: u32 = 0,
 
/// Start index of relocations belonging to this atom.
unwind_index: u32 = 0,
 
/// Count of relocations belonging to this atom.
unwind_count: u32 = 0,
};
 
pub const Alignment = @import("../../InternPool.zig").Alignment;
 
src/link/MachO/InternalObject.zig added: 163, removed: 47, total 116
@@ -115,7 +115,8 @@ fn addObjcSelrefsSection(
.has_subtractor = false,
},
});
atom.relocs = .{ .pos = 0, .len = 1 };
try atom.addExtra(.{ .rel_index = 0, .rel_count = 1 }, macho_file);
atom.flags.relocs = true;
self.num_rebase_relocs += 1;
 
return atom_index;
@@ -183,9 +184,11 @@ pub fn getAtomData(self: *const InternalObject, atom: Atom, buffer: []u8) !void
@memcpy(buffer, data[off..][0..size]);
}
 
pub fn getAtomRelocs(self: *const InternalObject, atom: Atom) []const Relocation {
pub fn getAtomRelocs(self: *const InternalObject, atom: Atom, macho_file: *MachO) []const Relocation {
if (!atom.flags.relocs) return &[0]Relocation{};
const extra = atom.getExtra(macho_file).?;
const relocs = self.sections.items(.relocs)[atom.n_sect];
return relocs.items[atom.relocs.pos..][0..atom.relocs.len];
return relocs.items[extra.rel_index..][0..extra.rel_count];
}
 
fn addString(self: *InternalObject, allocator: Allocator, name: [:0]const u8) error{OutOfMemory}!u32 {
 
src/link/MachO/Object.zig added: 163, removed: 47, total 116
@@ -690,11 +690,13 @@ fn initRelocs(self: *Object, macho_file: *MachO) !void {
if (!atom.flags.alive) continue;
if (next_reloc >= relocs.items.len) break;
const end_addr = atom.off + atom.size;
atom.relocs.pos = next_reloc;
const rel_index = next_reloc;
 
while (next_reloc < relocs.items.len and relocs.items[next_reloc].offset < end_addr) : (next_reloc += 1) {}
 
atom.relocs.len = next_reloc - atom.relocs.pos;
const rel_count = next_reloc - rel_index;
try atom.addExtra(.{ .rel_index = rel_index, .rel_count = rel_count }, macho_file);
atom.flags.relocs = true;
}
}
}
@@ -1004,7 +1006,8 @@ fn parseUnwindRecords(self: *Object, macho_file: *MachO) !void {
{}
 
const atom = rec.getAtom(macho_file);
atom.unwind_records = .{ .pos = start, .len = next_cu - start };
try atom.addExtra(.{ .unwind_index = start, .unwind_count = next_cu - start }, macho_file);
atom.flags.unwind = true;
}
}
 
@@ -1724,9 +1727,11 @@ pub fn getAtomData(self: *const Object, macho_file: *MachO, atom: Atom, buffer:
if (amt != buffer.len) return error.InputOutput;
}
 
pub fn getAtomRelocs(self: *const Object, atom: Atom) []const Relocation {
pub fn getAtomRelocs(self: *const Object, atom: Atom, macho_file: *MachO) []const Relocation {
if (!atom.flags.relocs) return &[0]Relocation{};
const extra = atom.getExtra(macho_file).?;
const relocs = self.sections.items(.relocs)[atom.n_sect];
return relocs.items[atom.relocs.pos..][0..atom.relocs.len];
return relocs.items[extra.rel_index..][0..extra.rel_count];
}
 
fn addString(self: *Object, allocator: Allocator, name: [:0]const u8) error{OutOfMemory}!u32 {
 
src/link/MachO/ZigObject.zig added: 163, removed: 47, total 116
@@ -163,7 +163,8 @@ pub fn addAtom(self: *ZigObject, macho_file: *MachO) !Symbol.Index {
const relocs_index = @as(u32, @intCast(self.relocs.items.len));
const relocs = try self.relocs.addOne(gpa);
relocs.* = .{};
atom.relocs = .{ .pos = relocs_index, .len = 0 };
try atom.addExtra(.{ .rel_index = relocs_index, .rel_count = 0 }, macho_file);
atom.flags.relocs = true;
 
return symbol_index;
}
@@ -190,13 +191,18 @@ pub fn getAtomData(self: ZigObject, macho_file: *MachO, atom: Atom, buffer: []u8
}
}
 
pub fn getAtomRelocs(self: *ZigObject, atom: Atom) []const Relocation {
const relocs = self.relocs.items[atom.relocs.pos];
return relocs.items[0..atom.relocs.len];
pub fn getAtomRelocs(self: *ZigObject, atom: Atom, macho_file: *MachO) []const Relocation {
if (!atom.flags.relocs) return &[0]Relocation{};
const extra = atom.getExtra(macho_file).?;
const relocs = self.relocs.items[extra.rel_index];
return relocs.items[0..extra.rel_count];
}
 
pub fn freeAtomRelocs(self: *ZigObject, atom: Atom) void {
self.relocs.items[atom.relocs.pos].clearRetainingCapacity();
pub fn freeAtomRelocs(self: *ZigObject, atom: Atom, macho_file: *MachO) void {
if (atom.flags.relocs) {
const extra = atom.getExtra(macho_file).?;
self.relocs.items[extra.rel_index].clearRetainingCapacity();
}
}
 
pub fn resolveSymbols(self: *ZigObject, macho_file: *MachO) void {
 
src/link/MachO/thunks.zig added: 163, removed: 47, total 116
@@ -43,7 +43,8 @@ pub fn createThunks(sect_id: u8, macho_file: *MachO) !void {
if (isReachable(atom, rel, macho_file)) continue;
try thunk.symbols.put(gpa, rel.target, {});
}
atom.thunk_index = thunk_index;
try atom.addExtra(.{ .thunk = thunk_index }, macho_file);
atom.flags.thunk = true;
}
 
thunk.value = try advance(header, thunk.size(), .@"4");