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zld: refactor nlist and reloc filtering logic

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This commit is contained in:
Jakub Konka 2021-07-11 21:25:04 +02:00
parent 2a880897b0
commit b8fce705ad
1 changed files with 32 additions and 38 deletions
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70
src/link/MachO/Object.zig
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@ -273,59 +273,56 @@ pub fn readLoadCommands(self: *Object, reader: anytype) !void {
}
}
fn findFirst(comptime T: type, haystack: []T, start: usize, predicate: anytype) usize {
if (!@hasDecl(@TypeOf(predicate), "predicate"))
@compileError("Predicate is required to define fn predicate(@This(), T) bool");
if (start == haystack.len) return start;
var i = start;
while (i < haystack.len) : (i += 1) {
if (predicate.predicate(haystack[i])) break;
}
return i;
}
const NlistWithIndex = struct {
nlist: macho.nlist_64,
index: u32,
fn lessThan(_: void, lhs: @This(), rhs: @This()) bool {
fn lessThan(_: void, lhs: NlistWithIndex, rhs: NlistWithIndex) bool {
return lhs.nlist.n_value < rhs.nlist.n_value;
}
fn filterInSection(symbols: []@This(), sect_id: u8) []@This() {
var start: usize = 0;
var end: usize = symbols.len;
fn filterInSection(symbols: []NlistWithIndex, sect: macho.section_64) []NlistWithIndex {
const Predicate = struct {
addr: u64,
while (true) {
var change = false;
if (symbols[start].nlist.n_sect != sect_id) {
start += 1;
change = true;
}
if (symbols[end - 1].nlist.n_sect != sect_id) {
end -= 1;
change = true;
fn predicate(self: @This(), symbol: NlistWithIndex) bool {
return symbol.nlist.n_value >= self.addr;
}
};
if (start == end) break;
if (!change) break;
}
const start = findFirst(NlistWithIndex, symbols, 0, Predicate{ .addr = sect.addr });
const end = findFirst(NlistWithIndex, symbols, start, Predicate{ .addr = sect.addr + sect.size });
return symbols[start..end];
}
};
fn filterRelocs(relocs: []macho.relocation_info, start: u64, end: u64) []macho.relocation_info {
if (relocs.len == 0) return relocs;
fn filterRelocs(relocs: []macho.relocation_info, start_addr: u64, end_addr: u64) []macho.relocation_info {
const Predicate = struct {
addr: u64,
var start_id: usize = 0;
var end_id: usize = relocs.len;
while (true) {
var change = false;
if (relocs[start_id].r_address >= end) {
start_id += 1;
change = true;
}
if (relocs[end_id - 1].r_address < start) {
end_id -= 1;
change = true;
fn predicate(self: @This(), rel: macho.relocation_info) bool {
return rel.r_address < self.addr;
}
};
if (start_id == end_id) break;
if (!change) break;
}
const start = findFirst(macho.relocation_info, relocs, 0, Predicate{ .addr = end_addr });
const end = findFirst(macho.relocation_info, relocs, start, Predicate{ .addr = start_addr });
return relocs[start_id..end_id];
return relocs[start..end];
}
const TextBlockParser = struct {
@ -501,10 +498,7 @@ pub fn parseTextBlocks(self: *Object, zld: *Zld) !void {
const relocs = mem.bytesAsSlice(macho.relocation_info, raw_relocs);
// Symbols within this section only.
const filtered_nlists = NlistWithIndex.filterInSection(
sorted_nlists.items,
sect_id + 1,
);
const filtered_nlists = NlistWithIndex.filterInSection(sorted_nlists.items, sect);
// Is there any padding between symbols within the section?
const is_splittable = self.header.?.flags & macho.MH_SUBSECTIONS_VIA_SYMBOLS != 0;