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zld: handle objc-specific sections

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This commit is contained in:
Jakub Konka
2021-06-21 14:16:10 +02:00
parent 5f9b4cba6d
commit a480ae6e37
1 changed files with 138 additions and 1 deletions
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139
src/link/MachO/Zld.zig
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@@ -73,6 +73,11 @@ gcc_except_tab_section_index: ?u16 = null,
unwind_info_section_index: ?u16 = null,
eh_frame_section_index: ?u16 = null,
objc_methlist_section_index: ?u16 = null,
objc_methname_section_index: ?u16 = null,
objc_methtype_section_index: ?u16 = null,
objc_classname_section_index: ?u16 = null,
// __DATA_CONST segment sections
got_section_index: ?u16 = null,
mod_init_func_section_index: ?u16 = null,
@@ -80,6 +85,8 @@ mod_term_func_section_index: ?u16 = null,
data_const_section_index: ?u16 = null,
objc_cfstring_section_index: ?u16 = null,
objc_classlist_section_index: ?u16 = null,
objc_imageinfo_section_index: ?u16 = null,
// __DATA segment sections
tlv_section_index: ?u16 = null,
@@ -90,6 +97,11 @@ data_section_index: ?u16 = null,
bss_section_index: ?u16 = null,
common_section_index: ?u16 = null,
objc_const_section_index: ?u16 = null,
objc_selrefs_section_index: ?u16 = null,
objc_classrefs_section_index: ?u16 = null,
objc_data_section_index: ?u16 = null,
globals: std.StringArrayHashMapUnmanaged(*Symbol) = .{},
imports: std.StringArrayHashMapUnmanaged(*Symbol) = .{},
unresolved: std.StringArrayHashMapUnmanaged(*Symbol) = .{},
@@ -612,7 +624,7 @@ fn getMatchingSection(self: *Zld, sect: Object.Section) !?MatchingSection {
const res: ?MatchingSection = blk: {
switch (sect.sectionType()) {
macho.S_4BYTE_LITERALS, macho.S_8BYTE_LITERALS, macho.S_16BYTE_LITERALS, macho.S_LITERAL_POINTERS => {
macho.S_4BYTE_LITERALS, macho.S_8BYTE_LITERALS, macho.S_16BYTE_LITERALS => {
if (self.text_const_section_index == null) {
self.text_const_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__const", "__TEXT", .{});
@@ -624,6 +636,44 @@ fn getMatchingSection(self: *Zld, sect: Object.Section) !?MatchingSection {
};
},
macho.S_CSTRING_LITERALS => {
if (mem.eql(u8, sectname, "__objc_methname")) {
// TODO it seems the common values within the sections in objects are deduplicated/merged
// on merging the sections' contents.
if (self.objc_methname_section_index == null) {
self.objc_methname_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__objc_methname", "__TEXT", .{
.flags = macho.S_CSTRING_LITERALS,
});
}
break :blk .{
.seg = self.text_segment_cmd_index.?,
.sect = self.objc_methname_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_methtype")) {
if (self.objc_methtype_section_index == null) {
self.objc_methtype_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__objc_methtype", "__TEXT", .{
.flags = macho.S_CSTRING_LITERALS,
});
}
break :blk .{
.seg = self.text_segment_cmd_index.?,
.sect = self.objc_methtype_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_classname")) {
if (self.objc_classname_section_index == null) {
self.objc_classname_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__objc_classname", "__TEXT", .{});
}
break :blk .{
.seg = self.text_segment_cmd_index.?,
.sect = self.objc_classname_section_index.?,
};
}
if (self.cstring_section_index == null) {
self.cstring_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__cstring", "__TEXT", .{
@@ -636,6 +686,24 @@ fn getMatchingSection(self: *Zld, sect: Object.Section) !?MatchingSection {
.sect = self.cstring_section_index.?,
};
},
macho.S_LITERAL_POINTERS => {
if (mem.eql(u8, segname, "__DATA") and mem.eql(u8, sectname, "__objc_selrefs")) {
if (self.objc_selrefs_section_index == null) {
self.objc_selrefs_section_index = @intCast(u16, data_seg.sections.items.len);
try data_seg.addSection(self.allocator, "__objc_selrefs", "__DATA", .{
.flags = macho.S_LITERAL_POINTERS,
});
}
break :blk .{
.seg = self.data_segment_cmd_index.?,
.sect = self.objc_selrefs_section_index.?,
};
}
// TODO investigate
break :blk null;
},
macho.S_MOD_INIT_FUNC_POINTERS => {
if (self.mod_init_func_section_index == null) {
self.mod_init_func_section_index = @intCast(u16, data_const_seg.sections.items.len);
@@ -799,6 +867,16 @@ fn getMatchingSection(self: *Zld, sect: Object.Section) !?MatchingSection {
.seg = self.text_segment_cmd_index.?,
.sect = self.gcc_except_tab_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_methlist")) {
if (self.objc_methlist_section_index == null) {
self.objc_methlist_section_index = @intCast(u16, text_seg.sections.items.len);
try text_seg.addSection(self.allocator, "__objc_methlist", "__TEXT", .{});
}
break :blk .{
.seg = self.text_segment_cmd_index.?,
.sect = self.objc_methlist_section_index.?,
};
} else {
if (self.text_const_section_index == null) {
self.text_const_section_index = @intCast(u16, text_seg.sections.items.len);
@@ -845,6 +923,56 @@ fn getMatchingSection(self: *Zld, sect: Object.Section) !?MatchingSection {
.seg = self.data_const_segment_cmd_index.?,
.sect = self.objc_cfstring_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_classlist")) {
if (self.objc_classlist_section_index == null) {
self.objc_classlist_section_index = @intCast(u16, data_const_seg.sections.items.len);
try data_const_seg.addSection(self.allocator, "__objc_classlist", "__DATA_CONST", .{});
}
break :blk .{
.seg = self.data_const_segment_cmd_index.?,
.sect = self.objc_classlist_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_imageinfo")) {
if (self.objc_imageinfo_section_index == null) {
self.objc_imageinfo_section_index = @intCast(u16, data_const_seg.sections.items.len);
try data_const_seg.addSection(self.allocator, "__objc_imageinfo", "__DATA_CONST", .{});
}
break :blk .{
.seg = self.data_const_segment_cmd_index.?,
.sect = self.objc_imageinfo_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_const")) {
if (self.objc_const_section_index == null) {
self.objc_const_section_index = @intCast(u16, data_seg.sections.items.len);
try data_seg.addSection(self.allocator, "__objc_const", "__DATA", .{});
}
break :blk .{
.seg = self.data_segment_cmd_index.?,
.sect = self.objc_const_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_classrefs")) {
if (self.objc_classrefs_section_index == null) {
self.objc_classrefs_section_index = @intCast(u16, data_seg.sections.items.len);
try data_seg.addSection(self.allocator, "__objc_classrefs", "__DATA", .{});
}
break :blk .{
.seg = self.data_segment_cmd_index.?,
.sect = self.objc_classrefs_section_index.?,
};
} else if (mem.eql(u8, sectname, "__objc_data")) {
if (self.objc_data_section_index == null) {
self.objc_data_section_index = @intCast(u16, data_seg.sections.items.len);
try data_seg.addSection(self.allocator, "__objc_data", "__DATA", .{});
}
break :blk .{
.seg = self.data_segment_cmd_index.?,
.sect = self.objc_data_section_index.?,
};
} else {
if (self.data_section_index == null) {
self.data_section_index = @intCast(u16, data_seg.sections.items.len);
@@ -896,6 +1024,9 @@ fn sortSections(self: *Zld) !void {
&self.cstring_section_index,
&self.ustring_section_index,
&self.text_const_section_index,
&self.objc_methname_section_index,
&self.objc_methtype_section_index,
&self.objc_classname_section_index,
&self.eh_frame_section_index,
};
for (indices) |maybe_index| {
@@ -922,6 +1053,8 @@ fn sortSections(self: *Zld) !void {
&self.mod_term_func_section_index,
&self.data_const_section_index,
&self.objc_cfstring_section_index,
&self.objc_classlist_section_index,
&self.objc_imageinfo_section_index,
};
for (indices) |maybe_index| {
const new_index: u16 = if (maybe_index.*) |index| blk: {
@@ -944,6 +1077,10 @@ fn sortSections(self: *Zld) !void {
// __DATA segment
const indices = &[_]*?u16{
&self.la_symbol_ptr_section_index,
&self.objc_const_section_index,
&self.objc_selrefs_section_index,
&self.objc_classrefs_section_index,
&self.objc_data_section_index,
&self.data_section_index,
&self.tlv_section_index,
&self.tlv_data_section_index,