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macho: preactively add zerofill sections in correct order

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The required order on macOS nowadays is:
* __data
* __thread_vars
* __thread_data
* __thread_bss
* __bss
This commit is contained in:
Jakub Konka 2021-08-27 10:45:56 +02:00
parent 8bd0687713
commit 705cd64080
1 changed files with 105 additions and 1 deletions
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106
src/link/MachO.zig
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@ -780,7 +780,7 @@ pub fn flush(self: *MachO, comp: *Compilation) !void {
}
try self.parseTextBlocks();
try self.sortSections();
// try self.sortSections();
try self.allocateTextSegment();
try self.allocateDataConstSegment();
try self.allocateDataSegment();
@ -4163,6 +4163,110 @@ pub fn populateMissingMetadata(self: *MachO) !void {
self.load_commands_dirty = true;
}
if (self.tlv_section_index == null) {
const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
self.tlv_section_index = @intCast(u16, data_segment.sections.items.len);
const needed_size = @sizeOf(u64) * self.base.options.symbol_count_hint;
const off = data_segment.findFreeSpace(needed_size, @alignOf(u64), null);
assert(off + needed_size <= data_segment.inner.fileoff + data_segment.inner.filesize); // TODO Must expand __DATA segment.
log.debug("found __thread_vars section free space 0x{x} to 0x{x}", .{ off, off + needed_size });
try data_segment.addSection(self.base.allocator, "__thread_vars", .{
.addr = data_segment.inner.vmaddr + off - data_segment.inner.fileoff,
.size = needed_size,
.offset = @intCast(u32, off),
.@"align" = 3, // 2^3 = @sizeOf(u64)
.flags = macho.S_THREAD_LOCAL_VARIABLES,
});
const match = MatchingSection{
.seg = self.data_segment_cmd_index.?,
.sect = self.tlv_section_index.?,
};
_ = try self.section_ordinals.getOrPut(self.base.allocator, match);
try self.block_free_lists.putNoClobber(self.base.allocator, match, .{});
self.load_commands_dirty = true;
}
if (self.tlv_data_section_index == null) {
const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
self.tlv_data_section_index = @intCast(u16, data_segment.sections.items.len);
const needed_size = @sizeOf(u64) * self.base.options.symbol_count_hint;
const off = data_segment.findFreeSpace(needed_size, @alignOf(u64), null);
assert(off + needed_size <= data_segment.inner.fileoff + data_segment.inner.filesize); // TODO Must expand __DATA segment.
log.debug("found __thread_data section free space 0x{x} to 0x{x}", .{ off, off + needed_size });
try data_segment.addSection(self.base.allocator, "__thread_data", .{
.addr = data_segment.inner.vmaddr + off - data_segment.inner.fileoff,
.size = needed_size,
.offset = @intCast(u32, off),
.@"align" = 3, // 2^3 = @sizeOf(u64)
.flags = macho.S_THREAD_LOCAL_REGULAR,
});
const match = MatchingSection{
.seg = self.data_segment_cmd_index.?,
.sect = self.tlv_data_section_index.?,
};
_ = try self.section_ordinals.getOrPut(self.base.allocator, match);
try self.block_free_lists.putNoClobber(self.base.allocator, match, .{});
self.load_commands_dirty = true;
}
if (self.tlv_bss_section_index == null) {
const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
self.tlv_bss_section_index = @intCast(u16, data_segment.sections.items.len);
const needed_size = @sizeOf(u64) * self.base.options.symbol_count_hint;
const off = data_segment.findFreeSpace(needed_size, @alignOf(u64), null);
assert(off + needed_size <= data_segment.inner.fileoff + data_segment.inner.filesize); // TODO Must expand __DATA segment.
log.debug("found __thread_bss section free space 0x{x} to 0x{x}", .{ off, off + needed_size });
try data_segment.addSection(self.base.allocator, "__thread_bss", .{
.addr = data_segment.inner.vmaddr + off - data_segment.inner.fileoff,
.size = needed_size,
.offset = @intCast(u32, off),
.@"align" = 3, // 2^3 = @sizeOf(u64)
.flags = macho.S_THREAD_LOCAL_ZEROFILL,
});
const match = MatchingSection{
.seg = self.data_segment_cmd_index.?,
.sect = self.tlv_bss_section_index.?,
};
_ = try self.section_ordinals.getOrPut(self.base.allocator, match);
try self.block_free_lists.putNoClobber(self.base.allocator, match, .{});
self.load_commands_dirty = true;
}
if (self.bss_section_index == null) {
const data_segment = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
self.bss_section_index = @intCast(u16, data_segment.sections.items.len);
const needed_size = @sizeOf(u64) * self.base.options.symbol_count_hint;
const off = data_segment.findFreeSpace(needed_size, @alignOf(u64), null);
assert(off + needed_size <= data_segment.inner.fileoff + data_segment.inner.filesize); // TODO Must expand __DATA segment.
log.debug("found __bss section free space 0x{x} to 0x{x}", .{ off, off + needed_size });
try data_segment.addSection(self.base.allocator, "__bss", .{
.addr = data_segment.inner.vmaddr + off - data_segment.inner.fileoff,
.size = 0,
.offset = @intCast(u32, off),
.@"align" = 3, // 2^3 = @sizeOf(u64)
.flags = macho.S_ZEROFILL,
});
const match = MatchingSection{
.seg = self.data_segment_cmd_index.?,
.sect = self.bss_section_index.?,
};
_ = try self.section_ordinals.getOrPut(self.base.allocator, match);
try self.block_free_lists.putNoClobber(self.base.allocator, match, .{});
self.load_commands_dirty = true;
}
if (self.linkedit_segment_cmd_index == null) {
self.linkedit_segment_cmd_index = @intCast(u16, self.load_commands.items.len);
const address_and_offset = self.nextSegmentAddressAndOffset();