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From 405801d8a8be734425eca4f3eebc56287804ac93 Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Sun, 5 Feb 2023 10:04:34 +0100
Subject: [PATCH] macho: temp fix alignment and enable some logs
---
src/link/MachO/Object.zig | 80 ++++++++++++++++++++++++++------------
src/link/MachO/ZldAtom.zig | 29 +++++++-------
src/link/MachO/zld.zig | 22 +++++------
3 files changed, 79 insertions(+), 52 deletions(-)
diff --git a/src/link/MachO/Object.zig b/src/link/MachO/Object.zig
index 401184da515..05638c1f858 100644
--- a/src/link/MachO/Object.zig
+++ b/src/link/MachO/Object.zig
@@ -54,12 +54,18 @@ atom_by_index_table: []AtomIndex = undefined,
/// Can be undefined as set together with in_symtab.
globals_lookup: []i64 = undefined,
+/// All relocs sorted and flattened.
+relocs: std.ArrayListUnmanaged(macho.relocation_info) = .{},
+sect_relocs_lookup: std.ArrayListUnmanaged(u32) = .{},
+
atoms: std.ArrayListUnmanaged(AtomIndex) = .{},
pub fn deinit(self: *Object, gpa: Allocator) void {
self.atoms.deinit(gpa);
gpa.free(self.name);
gpa.free(self.contents);
+ self.relocs.deinit(gpa);
+ self.sect_relocs_lookup.deinit(gpa);
if (self.in_symtab) |_| {
gpa.free(self.source_symtab_lookup);
gpa.free(self.source_address_lookup);
@@ -101,6 +107,10 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
return error.MismatchedCpuArchitecture;
}
+ const nsects = self.getSourceSections().len;
+ try self.sect_relocs_lookup.resize(allocator, nsects);
+ mem.set(u32, self.sect_relocs_lookup.items, 0);
+
var it = LoadCommandIterator{
.ncmds = self.header.ncmds,
.buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
@@ -110,13 +120,11 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
.SYMTAB => {
const symtab = cmd.cast(macho.symtab_command).?;
self.in_symtab = @ptrCast(
- [*]const macho.nlist_64,
- @alignCast(@alignOf(macho.nlist_64), &self.contents[symtab.symoff]),
+ [*]align(1) const macho.nlist_64,
+ self.contents.ptr + symtab.symoff,
)[0..symtab.nsyms];
self.in_strtab = self.contents[symtab.stroff..][0..symtab.strsize];
- const nsects = self.getSourceSections().len;
-
self.symtab = try allocator.alloc(macho.nlist_64, self.in_symtab.?.len + nsects);
self.source_symtab_lookup = try allocator.alloc(u32, self.in_symtab.?.len);
self.strtab_lookup = try allocator.alloc(u32, self.in_symtab.?.len);
@@ -192,6 +200,17 @@ const SymbolAtIndex = struct {
return mem.sliceTo(@ptrCast([*:0]const u8, ctx.in_strtab.?.ptr + off), 0);
}
+ fn getSymbolSeniority(self: SymbolAtIndex, ctx: Context) u2 {
+ const sym = self.getSymbol(ctx);
+ if (!sym.ext()) {
+ const sym_name = self.getSymbolName(ctx);
+ if (mem.startsWith(u8, sym_name, "l") or mem.startsWith(u8, sym_name, "L")) return 0;
+ return 1;
+ }
+ if (sym.weakDef() or sym.pext()) return 2;
+ return 3;
+ }
+
/// Performs lexicographic-like check.
/// * lhs and rhs defined
/// * if lhs == rhs
@@ -206,23 +225,15 @@ const SymbolAtIndex = struct {
if (lhs.sect() and rhs.sect()) {
if (lhs.n_value == rhs.n_value) {
if (lhs.n_sect == rhs.n_sect) {
- if (lhs.ext() and rhs.ext()) {
- if ((lhs.pext() or lhs.weakDef()) and (rhs.pext() or rhs.weakDef())) {
- return false;
- } else return rhs.pext() or rhs.weakDef();
- } else {
- const lhs_name = lhs_index.getSymbolName(ctx);
- const lhs_temp = mem.startsWith(u8, lhs_name, "l") or mem.startsWith(u8, lhs_name, "L");
- const rhs_name = rhs_index.getSymbolName(ctx);
- const rhs_temp = mem.startsWith(u8, rhs_name, "l") or mem.startsWith(u8, rhs_name, "L");
- if (lhs_temp and rhs_temp) {
- return false;
- } else return rhs_temp;
- }
+ const lhs_senior = lhs_index.getSymbolSeniority(ctx);
+ const rhs_senior = rhs_index.getSymbolSeniority(ctx);
+ if (lhs_senior == rhs_senior) {
+ return lessThanByNStrx(ctx, lhs_index, rhs_index);
+ } else return lhs_senior < rhs_senior;
} else return lhs.n_sect < rhs.n_sect;
} else return lhs.n_value < rhs.n_value;
} else if (lhs.undf() and rhs.undf()) {
- return false;
+ return lessThanByNStrx(ctx, lhs_index, rhs_index);
} else return rhs.undf();
}
@@ -393,6 +404,16 @@ pub fn splitIntoAtoms(self: *Object, zld: *Zld, object_id: u31) !void {
zld.sections.items(.header)[out_sect_id].sectName(),
});
+ // Parse all relocs for the input section, and sort in descending order.
+ // Previously, I have wrongly assumed the compilers output relocations for each
+ // section in a sorted manner which is simply not true.
+ const start = @intCast(u32, self.relocs.items.len);
+ if (self.getSourceRelocs(section.header)) |relocs| {
+ try self.relocs.appendUnalignedSlice(gpa, relocs);
+ std.sort.sort(macho.relocation_info, self.relocs.items[start..], {}, relocGreaterThan);
+ }
+ self.sect_relocs_lookup.items[section.id] = start;
+
const cpu_arch = zld.options.target.cpu.arch;
const sect_loc = filterSymbolsBySection(symtab[sect_sym_index..], sect_id + 1);
const sect_start_index = sect_sym_index + sect_loc.index;
@@ -559,7 +580,7 @@ pub fn getSourceSections(self: Object) []const macho.section_64 {
} else unreachable;
}
-pub fn parseDataInCode(self: Object) ?[]const macho.data_in_code_entry {
+pub fn parseDataInCode(self: Object) ?[]align(1) const macho.data_in_code_entry {
var it = LoadCommandIterator{
.ncmds = self.header.ncmds,
.buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
@@ -569,10 +590,7 @@ pub fn parseDataInCode(self: Object) ?[]const macho.data_in_code_entry {
.DATA_IN_CODE => {
const dice = cmd.cast(macho.linkedit_data_command).?;
const ndice = @divExact(dice.datasize, @sizeOf(macho.data_in_code_entry));
- return @ptrCast(
- [*]const macho.data_in_code_entry,
- @alignCast(@alignOf(macho.data_in_code_entry), &self.contents[dice.dataoff]),
- )[0..ndice];
+ return @ptrCast([*]align(1) const macho.data_in_code_entry, self.contents.ptr + dice.dataoff)[0..ndice];
},
else => {},
}
@@ -632,11 +650,23 @@ pub fn getSectionAliasSymbolPtr(self: *Object, sect_id: u8) *macho.nlist_64 {
return &self.symtab[self.getSectionAliasSymbolIndex(sect_id)];
}
-pub fn getRelocs(self: Object, sect: macho.section_64) []align(1) const macho.relocation_info {
- if (sect.nreloc == 0) return &[0]macho.relocation_info{};
+fn getSourceRelocs(self: Object, sect: macho.section_64) ?[]align(1) const macho.relocation_info {
+ if (sect.nreloc == 0) return null;
return @ptrCast([*]align(1) const macho.relocation_info, self.contents.ptr + sect.reloff)[0..sect.nreloc];
}
+pub fn getRelocs(self: Object, sect_id: u16) []const macho.relocation_info {
+ const sect = self.getSourceSection(sect_id);
+ const start = self.sect_relocs_lookup.items[sect_id];
+ const len = sect.nreloc;
+ return self.relocs.items[start..][0..len];
+}
+
+fn relocGreaterThan(ctx: void, lhs: macho.relocation_info, rhs: macho.relocation_info) bool {
+ _ = ctx;
+ return lhs.r_address > rhs.r_address;
+}
+
pub fn getSymbolName(self: Object, index: u32) []const u8 {
const strtab = self.in_strtab.?;
const sym = self.symtab[index];
diff --git a/src/link/MachO/ZldAtom.zig b/src/link/MachO/ZldAtom.zig
index 817aa816625..b42309598d7 100644
--- a/src/link/MachO/ZldAtom.zig
+++ b/src/link/MachO/ZldAtom.zig
@@ -465,7 +465,7 @@ pub fn resolveRelocs(
zld: *Zld,
atom_index: AtomIndex,
atom_code: []u8,
- atom_relocs: []align(1) const macho.relocation_info,
+ atom_relocs: []const macho.relocation_info,
reverse_lookup: []u32,
) !void {
const arch = zld.options.target.cpu.arch;
@@ -540,7 +540,7 @@ fn resolveRelocsArm64(
zld: *Zld,
atom_index: AtomIndex,
atom_code: []u8,
- atom_relocs: []align(1) const macho.relocation_info,
+ atom_relocs: []const macho.relocation_info,
reverse_lookup: []u32,
context: RelocContext,
) !void {
@@ -579,7 +579,6 @@ fn resolveRelocsArm64(
}
const target = parseRelocTarget(zld, atom_index, rel, reverse_lookup);
- const rel_offset = @intCast(u32, rel.r_address - context.base_offset);
log.debug(" RELA({s}) @ {x} => %{d} ('{s}') in object({?})", .{
@tagName(rel_type),
@@ -589,6 +588,7 @@ fn resolveRelocsArm64(
target.file,
});
+ const rel_offset = @intCast(u32, rel.r_address - context.base_offset);
const source_addr = blk: {
const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
break :blk source_sym.n_value + rel_offset;
@@ -596,7 +596,7 @@ fn resolveRelocsArm64(
const is_tlv = is_tlv: {
const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
const header = zld.sections.items(.header)[source_sym.n_sect - 1];
- break :is_tlv header.@"type"() == macho.S_THREAD_LOCAL_VARIABLES;
+ break :is_tlv header.type() == macho.S_THREAD_LOCAL_VARIABLES;
};
const target_addr = try getRelocTargetAddress(zld, rel, target, is_tlv);
@@ -831,7 +831,7 @@ fn resolveRelocsX86(
zld: *Zld,
atom_index: AtomIndex,
atom_code: []u8,
- atom_relocs: []align(1) const macho.relocation_info,
+ atom_relocs: []const macho.relocation_info,
reverse_lookup: []u32,
context: RelocContext,
) !void {
@@ -877,7 +877,7 @@ fn resolveRelocsX86(
const is_tlv = is_tlv: {
const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
const header = zld.sections.items(.header)[source_sym.n_sect - 1];
- break :is_tlv header.@"type"() == macho.S_THREAD_LOCAL_VARIABLES;
+ break :is_tlv header.type() == macho.S_THREAD_LOCAL_VARIABLES;
};
log.debug(" | source_addr = 0x{x}", .{source_addr});
@@ -1015,27 +1015,24 @@ pub fn getAtomCode(zld: *Zld, atom_index: AtomIndex) []const u8 {
return code[offset..][0..code_len];
}
-pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []align(1) const macho.relocation_info {
+pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []const macho.relocation_info {
const atom = zld.getAtomPtr(atom_index);
assert(atom.getFile() != null); // Synthetic atom shouldn't need to unique for relocs.
const object = zld.objects.items[atom.getFile().?];
- const source_sect = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
- const source_sect = object.getSourceSection(source_sym.n_sect - 1);
- assert(!source_sect.isZerofill());
- break :blk source_sect;
+ const source_sect_id = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
+ break :blk source_sym.n_sect - 1;
} else blk: {
// If there was no matching symbol present in the source symtab, this means
// we are dealing with either an entire section, or part of it, but also
// starting at the beginning.
const nbase = @intCast(u32, object.in_symtab.?.len);
const sect_id = @intCast(u16, atom.sym_index - nbase);
- const source_sect = object.getSourceSection(sect_id);
- assert(!source_sect.isZerofill());
- break :blk source_sect;
+ break :blk sect_id;
};
-
- const relocs = object.getRelocs(source_sect);
+ const source_sect = object.getSourceSection(source_sect_id);
+ assert(!source_sect.isZerofill());
+ const relocs = object.getRelocs(source_sect_id);
if (atom.cached_relocs_start == -1) {
const indexes = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
diff --git a/src/link/MachO/zld.zig b/src/link/MachO/zld.zig
index 3a2ea79c6ec..cee3f302c08 100644
--- a/src/link/MachO/zld.zig
+++ b/src/link/MachO/zld.zig
@@ -396,7 +396,7 @@ pub const Zld = struct {
break :blk null;
}
- switch (sect.@"type"()) {
+ switch (sect.type()) {
macho.S_4BYTE_LITERALS,
macho.S_8BYTE_LITERALS,
macho.S_16BYTE_LITERALS,
@@ -1701,7 +1701,7 @@ pub const Zld = struct {
break :outer;
}
}
- switch (header.@"type"()) {
+ switch (header.type()) {
macho.S_NON_LAZY_SYMBOL_POINTERS => {
try self.writeGotPointer(count, buffer.writer());
},
@@ -1718,7 +1718,7 @@ pub const Zld = struct {
break :outer;
}
}
- if (header.@"type"() == macho.S_SYMBOL_STUBS) {
+ if (header.type() == macho.S_SYMBOL_STUBS) {
try self.writeStubCode(atom_index, count, buffer.writer());
} else if (mem.eql(u8, header.sectName(), "__stub_helper")) {
try self.writeStubHelperCode(atom_index, buffer.writer());
@@ -1802,7 +1802,7 @@ pub const Zld = struct {
for (slice.items(.header)) |*header, sect_id| {
if (header.size == 0) continue;
if (self.requiresThunks()) {
- if (header.isCode() and !(header.@"type"() == macho.S_SYMBOL_STUBS) and !mem.eql(u8, header.sectName(), "__stub_helper")) continue;
+ if (header.isCode() and !(header.type() == macho.S_SYMBOL_STUBS) and !mem.eql(u8, header.sectName(), "__stub_helper")) continue;
}
var atom_index = slice.items(.first_atom_index)[sect_id];
@@ -1830,7 +1830,7 @@ pub const Zld = struct {
if (self.requiresThunks()) {
for (slice.items(.header)) |header, sect_id| {
if (!header.isCode()) continue;
- if (header.@"type"() == macho.S_SYMBOL_STUBS) continue;
+ if (header.type() == macho.S_SYMBOL_STUBS) continue;
if (mem.eql(u8, header.sectName(), "__stub_helper")) continue;
// Create jump/branch range extenders if needed.
@@ -1994,10 +1994,10 @@ pub const Zld = struct {
const section_precedence: u4 = blk: {
if (header.isCode()) {
if (mem.eql(u8, "__text", header.sectName())) break :blk 0x0;
- if (header.@"type"() == macho.S_SYMBOL_STUBS) break :blk 0x1;
+ if (header.type() == macho.S_SYMBOL_STUBS) break :blk 0x1;
break :blk 0x2;
}
- switch (header.@"type"()) {
+ switch (header.type()) {
macho.S_NON_LAZY_SYMBOL_POINTERS,
macho.S_LAZY_SYMBOL_POINTERS,
=> break :blk 0x0,
@@ -2121,7 +2121,7 @@ pub const Zld = struct {
// Finally, unpack the rest.
for (slice.items(.header)) |header, sect_id| {
- switch (header.@"type"()) {
+ switch (header.type()) {
macho.S_LITERAL_POINTERS,
macho.S_REGULAR,
macho.S_MOD_INIT_FUNC_POINTERS,
@@ -2252,7 +2252,7 @@ pub const Zld = struct {
// Finally, unpack the rest.
const slice = self.sections.slice();
for (slice.items(.header)) |header, sect_id| {
- switch (header.@"type"()) {
+ switch (header.type()) {
macho.S_LITERAL_POINTERS,
macho.S_REGULAR,
macho.S_MOD_INIT_FUNC_POINTERS,
@@ -2707,10 +2707,10 @@ pub const Zld = struct {
}
fn filterDataInCode(
- dices: []const macho.data_in_code_entry,
+ dices: []align(1) const macho.data_in_code_entry,
start_addr: u64,
end_addr: u64,
- ) []const macho.data_in_code_entry {
+ ) []align(1) const macho.data_in_code_entry {
const Predicate = struct {
addr: u64,
|