motiejus/zig
1
Fork 0
Code Releases Activity

zld: rewrite symbol allocations

Browse Source
This commit is contained in:
Jakub Konka
2021-05-03 14:56:45 +02:00
parent fcd57f0857
commit 00c3d57a51
1 changed files with 24 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files

99
src/link/MachO/Zld.zig
View File

@@ -202,16 +202,14 @@ pub fn link(self: *Zld, files: []const []const u8, out_path: []const u8) !void {
try self.resolveSymbols();
// self.printSymbols();
try self.resolveStubsAndGotEntries();
try self.updateMetadata();
try self.sortSections();
try self.allocateTextSegment();
try self.allocateDataConstSegment();
try self.allocateDataSegment();
self.allocateLinkeditSegment();
try self.allocateSymbols();
return error.Unfinished;
// try self.updateMetadata();
// try self.sortSections();
// try self.allocateTextSegment();
// try self.allocateDataConstSegment();
// try self.allocateDataSegment();
// self.allocateLinkeditSegment();
// try self.allocateSymbols();
// try self.allocateStubsAndGotEntries();
// try self.allocateCppStatics();
// try self.writeStubHelperCommon();
// try self.resolveRelocsAndWriteSections();
// try self.flush();
@@ -797,7 +795,7 @@ fn sortSections(self: *Zld) !void {
fn allocateTextSegment(self: *Zld) !void {
const seg = &self.load_commands.items[self.text_segment_cmd_index.?].Segment;
const nstubs = @intCast(u32, self.stubs.items().len);
const nstubs = @intCast(u32, self.stubs.items.len);
const base_vmaddr = self.load_commands.items[self.pagezero_segment_cmd_index.?].Segment.inner.vmsize;
seg.inner.fileoff = 0;
@@ -848,7 +846,7 @@ fn allocateTextSegment(self: *Zld) !void {
fn allocateDataConstSegment(self: *Zld) !void {
const seg = &self.load_commands.items[self.data_const_segment_cmd_index.?].Segment;
const nentries = @intCast(u32, self.got_entries.items().len);
const nentries = @intCast(u32, self.got_entries.items.len);
const text_seg = self.load_commands.items[self.text_segment_cmd_index.?].Segment;
seg.inner.fileoff = text_seg.inner.fileoff + text_seg.inner.filesize;
@@ -863,7 +861,7 @@ fn allocateDataConstSegment(self: *Zld) !void {
fn allocateDataSegment(self: *Zld) !void {
const seg = &self.load_commands.items[self.data_segment_cmd_index.?].Segment;
const nstubs = @intCast(u32, self.stubs.items().len);
const nstubs = @intCast(u32, self.stubs.items.len);
const data_const_seg = self.load_commands.items[self.data_const_segment_cmd_index.?].Segment;
seg.inner.fileoff = data_const_seg.inner.fileoff + data_const_seg.inner.filesize;
@@ -906,95 +904,46 @@ fn allocateSegment(self: *Zld, index: u16, offset: u64) !void {
}
fn allocateSymbols(self: *Zld) !void {
for (self.objects.items) |*object, object_id| {
for (object.locals.items()) |*entry| {
const source_sym = object.symtab.items[entry.value.index.?];
const source_sect_id = source_sym.n_sect - 1;
for (self.objects.items) |object, object_id| {
for (object.symbols.items) |sym| {
const reg = sym.cast(Symbol.Regular) orelse continue;
// TODO I am more and more convinced we should store the mapping as part of the Object struct.
const target_mapping = self.mappings.get(.{
.object_id = @intCast(u16, object_id),
.source_sect_id = source_sect_id,
.source_sect_id = reg.section,
}) orelse {
if (self.unhandled_sections.get(.{
.object_id = @intCast(u16, object_id),
.source_sect_id = source_sect_id,
.source_sect_id = reg.section,
}) != null) continue;
log.err("section not mapped for symbol '{s}'", .{entry.value.name});
log.err("section not mapped for symbol '{s}'", .{sym.name});
return error.SectionNotMappedForSymbol;
};
const source_seg = object.load_commands.items[object.segment_cmd_index.?].Segment;
const source_sect = source_seg.sections.items[source_sect_id];
const source_sect = source_seg.sections.items[reg.section];
const target_seg = self.load_commands.items[target_mapping.target_seg_id].Segment;
const target_sect = target_seg.sections.items[target_mapping.target_sect_id];
const target_addr = target_sect.addr + target_mapping.offset;
const n_value = source_sym.n_value - source_sect.addr + target_addr;
const address = reg.address - source_sect.addr + target_addr;
log.debug("resolving local symbol '{s}' at 0x{x}", .{ entry.value.name, n_value });
log.warn("resolving symbol '{s}' at 0x{x}", .{ sym.name, address });
// TODO there might be a more generic way of doing this.
var n_sect: u8 = 0;
var section: u8 = 0;
for (self.load_commands.items) |cmd, cmd_id| {
if (cmd != .Segment) break;
if (cmd_id == target_mapping.target_seg_id) {
n_sect += @intCast(u8, target_mapping.target_sect_id) + 1;
section += @intCast(u8, target_mapping.target_sect_id) + 1;
break;
}
n_sect += @intCast(u8, cmd.Segment.sections.items.len);
section += @intCast(u8, cmd.Segment.sections.items.len);
}
entry.value.address = n_value;
entry.value.section = n_sect;
}
}
for (self.symtab.items()) |*entry| {
if (entry.value.tag == .import) continue;
const object_id = entry.value.file orelse unreachable;
const object = self.objects.items[object_id];
const local = object.locals.get(entry.key) orelse unreachable;
log.debug("resolving {} symbol '{s}' at 0x{x}", .{ entry.value.tag, entry.key, local.address });
entry.value.address = local.address;
entry.value.section = local.section;
}
}
fn allocateStubsAndGotEntries(self: *Zld) !void {
for (self.got_entries.items()) |*entry| {
if (entry.value.tag == .import) continue;
const object = self.objects.items[entry.value.file];
entry.value.target_addr = target_addr: {
if (object.locals.get(entry.key)) |local| {
break :target_addr local.address;
}
const global = self.symtab.get(entry.key) orelse unreachable;
break :target_addr global.address;
};
log.debug("resolving GOT entry '{s}' at 0x{x}", .{
entry.key,
entry.value.target_addr,
});
}
}
fn allocateCppStatics(self: *Zld) !void {
for (self.objects.items) |*object| {
for (object.initializers.items) |*initializer| {
const sym = object.symtab.items[initializer.symbol];
const sym_name = object.getString(sym.n_strx);
initializer.target_addr = object.locals.get(sym_name).?.address;
log.debug("resolving C++ initializer '{s}' at 0x{x}", .{
sym_name,
initializer.target_addr,
});
reg.address = address;
reg.section = section;
}
}
}