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macho: fix marking sections for pruning in GC

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This commit is contained in:
Jakub Konka
2022-07-15 12:58:42 +02:00
parent d80fcc8a0b
commit 35a5a4a0e4
1 changed files with 42 additions and 36 deletions
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78
src/link/MachO.zig
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@@ -244,7 +244,6 @@ unnamed_const_atoms: UnnamedConstTable = .{},
decls: std.AutoArrayHashMapUnmanaged(Module.Decl.Index, ?MatchingSection) = .{},
gc_roots: std.AutoHashMapUnmanaged(*Atom, void) = .{},
gc_sections: std.AutoHashMapUnmanaged(MatchingSection, void) = .{},
const Entry = struct {
target: SymbolWithLoc,
@@ -3296,7 +3295,6 @@ pub fn deinit(self: *MachO) void {
self.locals_free_list.deinit(self.base.allocator);
self.unresolved.deinit(self.base.allocator);
self.gc_roots.deinit(self.base.allocator);
self.gc_sections.deinit(self.base.allocator);
for (self.objects.items) |*object| {
object.deinit(self.base.allocator);
@@ -5333,35 +5331,6 @@ fn pruneAndSortSectionsInSegment(self: *MachO, maybe_seg_id: *?u16, indices: []*
for (indices) |maybe_index| {
const old_idx = maybe_index.* orelse continue;
const sect = &sections[old_idx];
// Recalculate section alignment and size if required.
const match = MatchingSection{
.seg = seg_id,
.sect = old_idx,
};
if (self.gc_sections.get(match)) |_| blk: {
sect.@"align" = 0;
sect.size = 0;
var atom = self.atoms.get(match) orelse break :blk;
while (atom.prev) |prev| {
atom = prev;
}
while (true) {
const atom_alignment = try math.powi(u32, 2, atom.alignment);
const aligned_end_addr = mem.alignForwardGeneric(u64, sect.size, atom_alignment);
const padding = aligned_end_addr - sect.size;
sect.size += padding + atom.size;
sect.@"align" = @maximum(sect.@"align", atom.alignment);
if (atom.next) |next| {
atom = next;
} else break;
}
}
if (sect.size == 0) {
log.debug("pruning section {s},{s}", .{ sect.segName(), sect.sectName() });
maybe_index.* = null;
@@ -5550,6 +5519,11 @@ fn gcAtoms(self: *MachO) !void {
}
}
// Any section that ends up here will be updated, that is,
// its size and alignment recalculated.
var gc_sections = std.AutoHashMap(MatchingSection, void).init(gpa);
defer gc_sections.deinit();
atoms_it = self.atoms.iterator();
while (atoms_it.next()) |entry| {
const match = entry.key_ptr.*;
@@ -5602,18 +5576,22 @@ fn gcAtoms(self: *MachO) !void {
// account any padding that might have been left here.
sect.size -= atom.size;
_ = try gc_sections.put(match, {});
if (atom.prev) |prev| {
prev.next = atom.next;
}
if (atom.next) |next| {
next.prev = atom.prev;
} else {
// TODO I think a null would be better here.
// The section will be GCed in the next step.
entry.value_ptr.* = if (atom.prev) |prev| prev else undefined;
if (atom.prev) |prev| {
entry.value_ptr.* = prev;
} else {
// The section will be GCed in the next step.
entry.value_ptr.* = undefined;
sect.size = 0;
}
}
_ = try self.gc_sections.getOrPut(gpa, match);
}
if (orig_prev) |prev| {
@@ -5621,6 +5599,34 @@ fn gcAtoms(self: *MachO) !void {
} else break;
}
}
var gc_sections_it = gc_sections.iterator();
while (gc_sections_it.next()) |entry| {
const match = entry.key_ptr.*;
const sect = self.getSectionPtr(match);
if (sect.size == 0) continue; // Pruning happens automatically in next step.
sect.@"align" = 0;
sect.size = 0;
var atom = self.atoms.get(match).?;
while (atom.prev) |prev| {
atom = prev;
}
while (true) {
const atom_alignment = try math.powi(u32, 2, atom.alignment);
const aligned_end_addr = mem.alignForwardGeneric(u64, sect.size, atom_alignment);
const padding = aligned_end_addr - sect.size;
sect.size += padding + atom.size;
sect.@"align" = @maximum(sect.@"align", atom.alignment);
if (atom.next) |next| {
atom = next;
} else break;
}
}
}
fn updateSectionOrdinals(self: *MachO) !void {