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lib/std/Build/CheckObject: dump Mach-O dyld_info_only rebase data

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This commit is contained in:
Jakub Konka 2023-12-10 00:14:53 +01:00
parent 40952b4cdb
commit 5bda88f9a3
1 changed files with 95 additions and 3 deletions
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98
lib/std/Build/Step/CheckObject.zig
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@ -577,9 +577,10 @@ const MachODumper = struct {
const writer = output.writer();
var symtab: ?Symtab = null;
var segments = std.ArrayList(macho.segment_command_u64);
var sections = std.ArrayList(macho.section_64).init(gpa);
var imports = std.ArrayList([]const u8).init(gpa);
var text_seg: ?macho.segment_command_64 = null;
var text_seg: ?u8 = null;
var dyld_info_lc: ?macho.dyld_info_command = null;
try dumpHeader(hdr, writer);
@ -597,8 +598,10 @@ const MachODumper = struct {
for (cmd.getSections()) |sect| {
sections.appendAssumeCapacity(sect);
}
const seg_id: u8 = @intCast(segments.items.len);
try segments.append(seg);
if (mem.eql(u8, seg.segName(), "__TEXT")) {
text_seg = seg;
text_seg = seg_id;
}
},
.SYMTAB => {
@ -631,9 +634,13 @@ const MachODumper = struct {
if (dyld_info_lc) |lc| {
try writer.writeAll(dyld_info_label ++ "\n");
if (lc.rebase_size > 0) {
const data = bytes[lc.rebase_off..][0..lc.rebase_size];
try dumpRebaseInfo(gpa, data, segments.items, writer);
}
if (lc.export_size > 0) {
const data = bytes[lc.export_off..][0..lc.export_size];
try dumpExportsTrie(gpa, data, text_seg.?, writer);
try dumpExportsTrie(gpa, data, segments.items[text_seg.?], writer);
}
}
@ -994,6 +1001,91 @@ const MachODumper = struct {
}
}
fn dumpRebaseInfo(
gpa: Allocator,
data: []const u8,
segments: []const macho.segment_command_64,
writer: anytype,
) !void {
var rebases = std.ArrayList(u64).init(gpa);
defer rebases.deinit();
try parseRebaseInfo(data, segments, &rebases);
mem.sort(u64, rebases.items, {}, std.sort.asc(u64));
try writer.writeAll("rebase info\n");
for (rebases.items) |addr| {
try writer.print("0x{x}\n", .{addr});
}
}
fn parseRebaseInfo(
data: []const u8,
segments: []const macho.segment_command_64,
rebases: *std.ArrayList(u64),
) !void {
var stream = std.io.fixedBufferStream(data);
var creader = std.io.countingReader(stream.reader());
const reader = creader.reader();
var seg_id: ?u8 = null;
var offset: u64 = 0;
while (true) {
const byte = reader.readByte() catch break;
const opc = byte & macho.REBASE_OPCODE_MASK;
const imm = byte & macho.REBASE_IMMEDIATE_MASK;
switch (opc) {
macho.REBASE_OPCODE_DONE => break,
macho.REBASE_OPCODE_SET_TYPE_IMM => {},
macho.REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => {
seg_id = imm;
offset = try std.leb.readULEB128(u64, reader);
},
macho.REBASE_OPCODE_ADD_ADDR_IMM_SCALED => {
offset += imm * @sizeOf(u64);
},
macho.REBASE_OPCODE_ADD_ADDR_ULEB => {
const addend = try std.leb.readULEB128(u64, reader);
offset += addend;
},
macho.REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB => {
const addend = try std.leb.readULEB128(u64, reader);
const seg = segments.items[seg_id.?];
const addr = seg.vmaddr + offset;
try rebases.append(addr);
offset += addend + @sizeOf(u64);
},
macho.REBASE_OPCODE_DO_REBASE_IMM_TIMES,
macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES,
macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB,
=> {
var ntimes: u64 = 1;
var skip: u64 = 0;
switch (opc) {
macho.REBASE_OPCODE_DO_REBASE_IMM_TIMES => {
ntimes = imm;
},
macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES => {
ntimes = try std.leb.readULEB128(u64, reader);
},
macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB => {
ntimes = try std.leb.readULEB128(u64, reader);
skip = try std.leb.readULEB128(u64, reader);
},
else => unreachable,
}
const seg = segments.items[seg_id.?];
const base_addr = seg.vmaddr;
var count: usize = 0;
while (count < ntimes) : (count += 1) {
const addr = base_addr + offset;
try rebases.append(addr);
offset += skip + @sizeOf(u64);
}
},
else => break,
}
}
}
fn dumpExportsTrie(
gpa: Allocator,
data: []const u8,