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macho: add logic for expanding segments in memory

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This commit is contained in:
Jakub Konka 2022-09-15 13:48:00 +02:00
parent e601969244
commit 618c7a3546
3 changed files with 42 additions and 3 deletions
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1
src/link/Coff.zig
View File

@ -1135,6 +1135,7 @@ fn getDeclOutputSection(self: *Coff, decl: *Module.Decl) u16 {
}
switch (zig_ty) {
// TODO: what if this is a function pointer?
.Fn => break :blk self.text_section_index.?,
else => {
if (val.castTag(.variable)) |_| {

1
src/link/Elf.zig
View File

@ -2320,6 +2320,7 @@ fn getDeclPhdrIndex(self: *Elf, decl: *Module.Decl) !u16 {
}
switch (zig_ty) {
// TODO: what if this is a function pointer?
.Fn => break :blk self.phdr_load_re_index.?,
else => {
if (val.castTag(.variable)) |_| {

43
src/link/MachO.zig
View File

@ -2839,7 +2839,9 @@ pub fn lowerUnnamedConst(self: *MachO, typed_value: TypedValue, decl_index: Modu
const required_alignment = typed_value.ty.abiAlignment(self.base.options.target);
atom.size = code.len;
atom.alignment = required_alignment;
const sect_id = self.getDeclOutputSection(decl);
// TODO: work out logic for disambiguating functions from function pointers
// const sect_id = self.getDeclOutputSection(decl);
const sect_id = self.data_const_section_index.?;
const symbol = atom.getSymbolPtr(self);
symbol.n_strx = name_str_index;
symbol.n_type = macho.N_SECT;
@ -2956,6 +2958,7 @@ fn getDeclOutputSection(self: *MachO, decl: *Module.Decl) u8 {
}
switch (zig_ty) {
// TODO: what if this is a function pointer?
.Fn => break :blk self.text_section_index.?,
else => {
if (val.castTag(.variable)) |_| {
@ -3709,6 +3712,41 @@ fn allocateSection(self: *MachO, segname: []const u8, sectname: []const u8, opts
return section_id;
}
fn moveSectionInVirtualMemory(self: *MachO, sect_id: u32, needed_size: u64) !void {
const header = &self.sections.items(.header)[sect_id];
const segment = &self.segments.items[self.sections.items(.segment_index)[sect_id]];
const increased_size = padToIdeal(needed_size);
const old_aligned_end = segment.vmaddr + segment.vmsize;
const new_aligned_end = segment.vmaddr + mem.alignForwardGeneric(u64, increased_size, self.page_size);
const diff = new_aligned_end - old_aligned_end;
log.debug("shifting every segment after {s},{s} in virtual memory by {x}", .{
header.segName(),
header.sectName(),
diff,
});
// TODO: enforce order by increasing VM addresses in self.sections container.
for (self.sections.items(.header)[sect_id + 1 ..]) |*next_header, next_sect_id| {
const index = sect_id + 1 + next_sect_id;
const maybe_last_atom = &self.sections.items(.last_atom)[index];
const next_segment = &self.segments.items[self.sections.items(.segment_index)[index]];
next_header.addr += diff;
next_segment.vmaddr += diff;
if (maybe_last_atom.*) |last_atom| {
var atom = last_atom;
while (true) {
const sym = atom.getSymbolPtr(self);
sym.n_value += diff;
if (atom.prev) |prev| {
atom = prev;
} else break;
}
}
}
}
fn allocateAtom(self: *MachO, atom: *Atom, new_atom_size: u64, alignment: u64) !u64 {
const tracy = trace(@src());
defer tracy.end();
@ -3816,13 +3854,12 @@ fn allocateAtom(self: *MachO, atom: *Atom, new_atom_size: u64, alignment: u64) !
const sect_vm_capacity = self.allocatedVirtualSize(segment.vmaddr);
if (needed_size > sect_vm_capacity) {
self.markRelocsDirtyByAddress(segment.vmaddr + needed_size);
@panic("TODO grow section in VM");
try self.moveSectionInVirtualMemory(sect_id, needed_size);
}
header.size = needed_size;
segment.filesize = needed_size;
segment.vmsize = mem.alignForwardGeneric(u64, needed_size, self.page_size);
log.warn("updating {s},{s}: {x}, {x}", .{ header.segName(), header.sectName(), segment.vmsize, segment.filesize });
maybe_last_atom.* = atom;
self.segment_table_dirty = true;