mirror of
https://github.com/rui314/mold.git
synced 2024-09-20 09:27:45 +03:00
114 lines
2.7 KiB
C++
114 lines
2.7 KiB
C++
#include "mold.h"
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namespace mold::macho {
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template <typename E>
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static std::vector<Subsection<E> *> collect_root_set(Context<E> &ctx) {
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std::vector<Subsection<E> *> rootset;
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auto mark = [&](Symbol<E> *sym) {
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if (sym && sym->subsec)
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rootset.push_back(sym->subsec);
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};
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mark(ctx.arg.entry);
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if (ctx.output_type == MH_DYLIB || ctx.output_type == MH_BUNDLE)
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for (ObjectFile<E> *file : ctx.objs)
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for (Symbol<E> *sym : file->syms)
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if (sym->file == file && sym->scope == SCOPE_EXTERN)
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mark(sym);
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return rootset;
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}
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template <typename E>
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static void visit(Context<E> &ctx, Subsection<E> &subsec) {
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if (subsec.is_alive.exchange(true))
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return;
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for (Relocation<E> &rel : subsec.get_rels()) {
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if (rel.sym) {
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if (rel.sym->subsec)
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visit(ctx, *rel.sym->subsec);
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} else {
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visit(ctx, *rel.subsec);
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}
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}
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for (UnwindRecord<E> &rec : subsec.get_unwind_records()) {
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visit(ctx, *rec.subsec);
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if (rec.lsda)
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visit(ctx, *rec.lsda);
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if (rec.personality && rec.personality->subsec)
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visit(ctx, *rec.personality->subsec);
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}
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}
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template <typename E>
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static bool refers_live_subsection(Subsection<E> &subsec) {
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for (Relocation<E> &rel : subsec.get_rels()) {
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if (rel.sym) {
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if (!rel.sym->subsec || rel.sym->subsec->is_alive)
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return true;
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} else {
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if (rel.subsec->is_alive)
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return true;
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}
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}
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return false;
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}
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template <typename E>
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static void mark(Context<E> &ctx, const std::vector<Subsection<E> *> &rootset) {
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for (ObjectFile<E> *file : ctx.objs)
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for (Subsection<E> *subsec : file->subsections)
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subsec->is_alive = false;
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for (Subsection<E> *subsec : rootset)
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visit(ctx, *subsec);
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bool repeat;
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do {
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repeat = false;
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for (ObjectFile<E> *file : ctx.objs) {
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for (Subsection<E> *subsec : file->subsections) {
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if ((subsec->isec.hdr.attr & S_ATTR_LIVE_SUPPORT) &&
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!subsec->is_alive &&
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refers_live_subsection(*subsec)) {
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visit(ctx, *subsec);
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repeat = true;
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}
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}
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}
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} while (repeat);
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}
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template <typename E>
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static void sweep(Context<E> &ctx) {
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for (ObjectFile<E> *file : ctx.objs)
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for (Symbol<E> *&sym : file->syms)
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if (sym->file == file && sym->subsec && !sym->subsec->is_alive)
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sym = nullptr;
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for (ObjectFile<E> *file : ctx.objs) {
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std::erase_if(file->subsections, [](const Subsection<E> *subsec) {
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return !subsec->is_alive;
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});
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}
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}
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template <typename E>
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void dead_strip(Context<E> &ctx) {
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std::vector<Subsection<E> *> rootset = collect_root_set(ctx);
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mark(ctx, rootset);
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sweep(ctx);
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}
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#define INSTANTIATE(E) \
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template void dead_strip(Context<E> &)
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INSTANTIATE_ALL;
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} // namespace mold::macho
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