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xo-gc: verify visits+checks to-space contents

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This commit is contained in:
Roland Conybeare 2026-03-27 13:16:10 -04:00
commit eba6e437be
2 changed files with 64 additions and 8 deletions
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19
include/xo/gc/DX1Collector.hpp
View file

@ -84,12 +84,23 @@ namespace xo {
*
**/
struct VerifyStats {
bool is_ok() const noexcept {
return (n_from_ == 0) && (n_fwd_ == 0) && (n_no_iface_ == 0);
}
void clear() { *this = VerifyStats(); }
std::uint32_t n_gc_root_ = 0;
std::uint32_t n_ext_ = 0;
std::uint32_t n_from_ = 0;
std::uint32_t n_to_ = 0;
/** number of gc roots examined **/
std::uint32_t n_gc_root_ = 0;
std::uint32_t n_ext_ = 0;
/** number of from-space objects encountered. Fatal if non-zero **/
std::uint32_t n_from_ = 0;
/** number of to-space objects encountered. **/
std::uint32_t n_to_ = 0;
/** counts forwarding object encountered in to-space scan. Fatal if non-zero **/
std::uint32_t n_fwd_ = 0;
/** counts missing GCObject interface. Fatal if non-zero **/
std::uint32_t n_no_iface_ = 0;
};
// ----- DX1Collector -----

53
src/gc/DX1Collector.cpp
View file

@ -367,6 +367,8 @@ namespace xo {
// Add run state so DX1Collector can recognize forward_inplace()
// calls made for the purpose of checking child pointers.
auto self = this->ref<ACollector>();
GCRunState saved_runstate = runstate_;
{
this->runstate_ = GCRunState::verify();
@ -386,7 +388,7 @@ namespace xo {
// - X1Collector::forward_inplace() -> _verify_aux()
//
gco.forward_children(this->ref<ACollector>());
gco.forward_children(self);
}
@ -397,12 +399,49 @@ namespace xo {
++verify_stats_.n_gc_root_;
}
// 3. scan to-space for each generation
for (Generation g(0); g < config_.n_generation_; ++g) {
const DArena * space = this->get_space(role::to_space(), g);
for (const AllocInfo & info : *space) {
if (info.is_forwarding_tseq()) {
++verify_stats_.n_fwd_;
} else {
typeseq tseq(info.tseq());
const AGCObject * iface = this->lookup_type(tseq);
if (iface) {
const void * data = info.payload().first;
// assembled fop for gc-aware object
obj<AGCObject> gco(iface, const_cast<void *>(data));
// forward_children is hijacked here to verify
// child pointer validity.
//
// Nested control reenters
// X1Collector::forward_inplace()
//
gco.forward_children(self);
} else {
++verify_stats_.n_no_iface_;
continue;
}
}
}
}
}
// restore run state at end of verify cycle
this->runstate_ = saved_runstate;
return true;
bool ok = verify_stats_.is_ok();
return ok;
}
const AGCObject *
@ -424,6 +463,7 @@ namespace xo {
xtag("types.hi", object_types_.hi_));
assert(false);
return nullptr;
}
return target;
@ -487,6 +527,7 @@ namespace xo {
if (config_.sanitize_flag_) {
log && log("step 0a : verify");
this->verify_ok();
}
log && log("step 0b : update run state");
@ -514,12 +555,16 @@ namespace xo {
if (config_.sanitize_flag_) {
log && log("step 4b : verify");
this->verify_ok();
bool ok = this->verify_ok();
log && log(xtag("n-gc-root", verify_stats_.n_gc_root_),
xtag("n-ext", verify_stats_.n_ext_),
xtag("n-from", verify_stats_.n_from_),
xtag("n-to", verify_stats_.n_to_));
xtag("n-to", verify_stats_.n_to_),
xtag("n-fwd", verify_stats_.n_fwd_),
xtag("n-no-iface", verify_stats_.n_no_iface_));
assert(ok);
}
}