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xo-ordinaltree: expand unittest + debug logging

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This commit is contained in:
Roland Conybeare 2025-12-05 18:38:29 -05:00
commit bd8ca68e7c
4 changed files with 106 additions and 14 deletions
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4
include/xo/alloc/GC.hpp
View file

@ -107,7 +107,7 @@ namespace xo {
bool is_dead() const { return false; }
MutationLogEntry update_parent_moved(IObject * parent_to) const;
void fixup_parent_child_moved(IObject * child_to) { *lhs_ = child_to; }
void fixup_parent_child_moved(IObject * child_to);
private:
IObject * parent_ = nullptr;
@ -341,7 +341,7 @@ namespace xo {
* is recorded in mutation log,
* given an object @p parent that contains object pointer @p lhs
**/
virtual bool check_write_barrier(IObject * parent, IObject ** lhs, bool may_throw) const final;
virtual bool check_write_barrier(const void * parent, const void * const * lhs, bool may_throw) const final;
virtual std::byte * alloc(std::size_t z) final override;
virtual std::byte * alloc_gc_copy(std::size_t z, const void * src) final override;

79
src/alloc/GC.cpp
View file

@ -58,6 +58,12 @@ namespace xo {
reinterpret_cast<IObject **>(lhs_to));
}
void
MutationLogEntry::fixup_parent_child_moved(IObject * child_to)
{
*(this->lhs_) = child_to;
}
GC::GC(const Config & config)
: config_{config}
{
@ -508,12 +514,17 @@ namespace xo {
assert(retval);
log && log(xtag("retval", retval));
return retval;
}
void
GC::assign_member(IObject * parent, IObject ** lhs, IObject * rhs)
{
scope log(XO_DEBUG(config_.debug_flag_),
xtag("parent", parent), xtag("lhs", lhs), xtag("rhs", rhs));
++gc_statistics_.n_mutation_;
*lhs = rhs;
@ -532,23 +543,28 @@ namespace xo {
{
case generation_result::tenured:
/* only need to log mutations that create tenured->nursery pointers */
log && log(xtag("act", "any->T no log"));
return;
case generation_result::nursery:
switch (tospace_generation_of(parent)) {
case generation_result::nursery:
if (is_before_checkpoint(parent)) {
log && log(xtag("act", "N1->N0 must mlog"));
// N1->N0, so must log
this->mutation_log_[role2int(role::to_space)]->push_back(MutationLogEntry(parent, lhs));
++(this->gc_statistics_.n_logged_mutation_);
++(this->gc_statistics_.n_xckp_mutation_);
} else {
// parent in N0, not an xckp mutation
return;
log && log(xtag("act", "N0->any no long"));
}
break;
case generation_result::tenured:
// T->N, so must log
log && log(xtag("act", "T->N must mlog"));
this->mutation_log_[role2int(role::to_space)]->push_back(MutationLogEntry(parent, lhs));
++(this->gc_statistics_.n_logged_mutation_);
++(this->gc_statistics_.n_xgen_mutation_);
@ -556,11 +572,13 @@ namespace xo {
case generation_result::not_found:
// parent is global
// This may be ok (provided lhs is a gc root)
log && log(xtag("act", "root->any no log"));
break;
}
break;
case generation_result::not_found:
log && log(xtag("act", "any->root no log"));
// child is global;
// logging not required
@ -571,6 +589,8 @@ namespace xo {
void
GC::forward_inplace(IObject ** lhs)
{
scope log(XO_DEBUG(config_.debug_flag_), xtag("lhs", lhs));
Object::_forward_inplace(lhs, this);
}
@ -588,10 +608,13 @@ namespace xo {
}
bool
GC::check_write_barrier(IObject * parent,
IObject ** lhs,
GC::check_write_barrier(const void * parent,
const void * const * lhs,
bool may_throw_flag) const
{
scope log(XO_DEBUG(config_.debug_flag_),
xtag("P", parent), xtag("L", lhs));
if (!this->contains(parent)) {
if (may_throw_flag) {
throw std::runtime_error(tostr("GC::check_write_barrier",
@ -601,10 +624,11 @@ namespace xo {
return false;
}
#ifdef NOPE // don't want to assume IObject*
std::size_t parent_z = parent->_shallow_size();
std::byte * parent_addr = reinterpret_cast<std::byte *>(parent);
std::byte * lhs_addr = reinterpret_cast<std::byte *>(lhs);
const std::byte * parent_addr = reinterpret_cast<const std::byte *>(parent);
const std::byte * lhs_addr = reinterpret_cast<const std::byte *>(lhs);
if ((lhs_addr < parent_addr) || (parent_addr + parent_z < lhs_addr)) {
if (may_throw_flag) {
@ -617,12 +641,21 @@ namespace xo {
}
return false;
}
#endif
IObject * rhs = *lhs;
const void * rhs = *lhs;
if (!rhs)
return true;
auto parent_gen = tospace_generation_of(parent);
auto rhs_gen = tospace_generation_of(rhs);
log && log(xtag("C", rhs),
xtag("gen(P)", parent_gen), xtag("gen(C)", rhs_gen),
xtag("P.before-ckp", is_before_checkpoint(parent)),
xtag("C.before-ckp", is_before_checkpoint(rhs)));
switch(parent_gen) {
case generation_result::nursery:
if (is_before_checkpoint(parent)) {
@ -630,21 +663,25 @@ namespace xo {
case generation_result::nursery:
if (is_before_checkpoint(rhs)) {
/* no mlog entry needed */
log && log(xtag("msg", "N1->N1 - trivial"));
return true;
} else {
/* need to check mlog */
;
log && log(xtag("msg", "N1->N0 - xgen"));
}
break;
case generation_result::tenured:
/* no mlog entry needed */
log && log(xtag("msg", "N1->T - trivial"));
return true;
case generation_result::not_found:
/* possible non-gc rhs */
log && log(xtag("msg", "non-gc rhs - trivial"));
return true;
}
} else {
/* no mlog entry needed */
log && log(xtag("msg", "N0->any - trivial"));
return true;
}
break;
@ -652,16 +689,21 @@ namespace xo {
switch(rhs_gen) {
case generation_result::nursery:
/* need to check mlog */
log && log(xtag("msg", "T->N - xgen"));
break;
case generation_result::tenured:
/* no mlog entry needed */
log && log(xtag("msg", "T->T - trivial"));
return true;
case generation_result::not_found:
/* possible non-gc rhs */
log && log(xtag("msg", "non-gc rhs - trivial"));
return true;
}
break;
case generation_result::not_found:
/* already excluded -> impossible */
log && log(xtag("msg", "assert"));
assert(false && "already verified parent owned by GC");
}
@ -669,7 +711,7 @@ namespace xo {
* search mutation log + verify such entry exists
*/
for (MutationLogEntry & mlog : *(mutation_log_[role2int(role::to_space)])) {
if ((mlog.parent() == parent) && (mlog.lhs() == lhs)) {
if ((mlog.parent() == parent) && ((const void * const *)mlog.lhs() == lhs)) {
return true;
}
mlog.lhs();
@ -872,7 +914,7 @@ namespace xo {
for (MutationLogEntry & from_entry : *from_mlog)
{
if (log) {
if (i_from % 10000 == 0)
if (i_from % 10000 == 0 || true)
log(xtag("i_from", i_from));
}
@ -905,8 +947,12 @@ namespace xo {
++n_rescue;
log && log(xtag("parent", parent), xtag("act", "move child"), xtag("child.from", child_from));
Object::_deep_move(child_from, this, per_type_stats);
log && log(xtag("child.to", child_from->_destination()));
// C forwards to C', fall thru to parent fixup below
// (a) T->N1'
// (c) T->T
@ -924,13 +970,24 @@ namespace xo {
IObject * child_to = child_from->_destination();
log && log(xtag("act", "fixup parent"), xtag("parent", parent), xtag("lhs", from_entry.lhs()), xtag("child.from", child_from), xtag("child.to", child_to));
from_entry.fixup_parent_child_moved(child_to);
{
// verify fixup was effective
IObject * child_from2 = from_entry.child();
assert(child_from2 == child_to);
}
// P->C', loc(C') in {N1', T'}
if (tospace_generation_of(child_to) == generation_result::nursery) {
// (b) loc(P)=T, loc(C')=N1'; also case (a)
log && log(xtag("act", "still xgen -> keep mlog entry"));
// still have xgen pointer, so need mlog for it
to_mlog->push_back(from_entry);
} else {
@ -972,6 +1029,8 @@ namespace xo {
}
} else {
log && log("defer");
// loc(P) = N1, loc(C) = N0, P may be garbage
// Includes cases:
// (e) P->C, C not moved
@ -1347,7 +1406,7 @@ namespace xo {
void
GC::execute_gc(generation upto)
{
scope log(XO_DEBUG(config_.stats_flag_));
scope log(XO_DEBUG(config_.stats_flag_ || config_.debug_flag_));
auto t0 = std::chrono::steady_clock::now();

14
src/alloc/Object.cpp
View file

@ -42,18 +42,24 @@ namespace xo {
Object::_forward(IObject * src,
gc::IAlloc * gc)
{
scope log(XO_DEBUG(gc->debug_flag()), xtag("src", src));
if (!src)
return src;
if (src->_is_forwarded())
if (src->_is_forwarded()) {
log && log("already forwarded", xtag("dest", src->_offset_destination(src)));
return src->_offset_destination(src);
}
if (gc->check_move(src)) {
log && log("needs forwarding");
Object::_shallow_move(src, gc);
/* *src is now a forwarding pointer to a copy in to-space */
return src->_offset_destination(src);
} else {
log && log("already tenured + incr collection");
/* don't move tenured objects during incremental collection */
return src;
}
@ -62,6 +68,8 @@ namespace xo {
IObject *
Object::_deep_move(IObject * from_src, gc::GC * gc, gc::ObjectStatistics * /*stats*/)
{
scope log(XO_DEBUG(gc->config().debug_flag_));
using gc::generation;
if (!from_src)
@ -146,13 +154,15 @@ namespace xo {
do {
fixup_work = 0;
auto fixup_generation = [gc, &gray_lo_v](generation gen) {
auto fixup_generation = [gc, &log, &gray_lo_v](generation gen) {
std::size_t work = 0;
while(gray_lo_v[gen2int(gen)] < gc->free_ptr(gen)) {
Object * x = reinterpret_cast<Object *>(gray_lo_v[gen2int(gen)]);
// update per-class stats here
log && log("fwd children", xtag("x", x));
std::size_t xz = x->_forward_children(gc);
// must pad xz to multiple of word size,

23
utest/GC.test.cpp
View file

@ -202,6 +202,29 @@ namespace xo {
vector_type member2_;
bool ctor_ran_ = false;
};
#ifdef NOT_YET
struct MemberType2 {
public:
MemberType2() = default;
/** GC hooks rely on copy constructor. But can't write it without allocator state.
* Therefore: need copy-like constructor that takes allocator argument
**/
template <typename Allocator>
explicit MemberType2(Allocator & alloc, uint64 payload) {
using traits = gc_allocator_traits<Allocator>;
uint64_t * ptr = traits::allocate(alloc, 1);
this->payload_ = payload;
this->ctor_ran_ = true;
}
uint64_t * payload_ = nullptr;
bool ctor_ran_ = false;
}
#endif
}
TEST_CASE("vector_custom_allocator", "[alloc][vector]")