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xo-gc stack: refactor + streamline.

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Retiring unused Collector typealiases.
Fix #include topology.
Fix/improve write barrier setup.
This commit is contained in:
Roland Conybeare 2026-05-02 13:49:29 -04:00
commit 8336f0a47a
6 changed files with 63 additions and 41 deletions
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4
include/xo/gc/DX1Collector.hpp
View file

@ -307,7 +307,9 @@ namespace xo {
// ----- mutation -----
/** Modify a gc-owned pointer @p *p_lhs, within allocation @p parent,
/** DEPRECATED. Prefer .barrier_assign_aux().
*
* Modify a gc-owned pointer @p *p_lhs, within allocation @p parent,
* to point to @p rhs.
*
* Motivation: need special handling for cross-generational pointers with

22
include/xo/gc/MutationLogStore.hpp
View file

@ -55,14 +55,22 @@ namespace xo {
void verify_ok() noexcept;
/** on behalf of gc-aware object store @p gc,
* change the value of a child pointer at @p p_lhs
* with parent object @p parent. p_lhs and parent must belong
* to the same allocation.
* change the value of a child pointer {@p lhs_iface, @p *lhs_data}
* with parent object @p parent, to point to {@p rhs_iface, @p rhs_data}
* p_lhs and parent must belong to the same allocation.
*
* @p lhs_iface can be nullptr, if parent holds ordinary pointer
* instead of fop (i.e. DRepr* instead of obj<AFacet,DRepr>).
*
* @p rhs_iface must be non-null, it's load-bearing for mlog entry
* snapshot member.
**/
void assign_member(GCObjectStore * gc,
void * parent,
obj<AGCObject> * p_lhs,
obj<AGCObject> rhs);
void assign_member_aux(GCObjectStore * gc,
void * parent,
AGCObject * lhs_iface,
void ** lhs_data,
AGCObject * rhs_iface,
void * rhs_data);
/** swap {to, from} roles
**/

1
include/xo/gc/detail/ICollector_DX1Collector.hpp
View file

@ -104,6 +104,7 @@ Return false if installation fails (e.g. memory exhausted) **/
**/
static void request_gc(DX1Collector & self, Generation upto);
/** Assign pointer @p p_lhs to destination @p rhs, within parent allocation @p parent
DEPRECATED. Only used in MockCollector for gc unit test
Require: gc not in progress **/
static void assign_member(DX1Collector & self, void * parent, obj<AGCObject> * p_lhs, obj<AGCObject> & rhs);

30
src/gc/DX1Collector.cpp
View file

@ -620,24 +620,11 @@ namespace xo {
void
DX1Collector::assign_member(void * parent, obj<AGCObject> * p_lhs, obj<AGCObject> rhs)
{
scope log(XO_DEBUG(config_.debug_flag_),
xtag("parent", parent), xtag("lhs", p_lhs), xtag("rhs", rhs.data()));
// ++ stats.n_mutation_;
if (runstate_.is_running()) {
*p_lhs = rhs;
// for removal of all doubt:
// don't log mutations during GC cycle.
// That said: should not be happening!
assert(false);
return;
} else {
mlog_store_.assign_member(&gco_store_, parent, p_lhs, rhs);
}
this->barrier_assign_aux(parent,
p_lhs->iface(),
p_lhs->opaque_data_addr(),
rhs.iface(),
rhs.opaque_data());
} /*assign_member*/
DX1CollectorIterator
@ -702,7 +689,12 @@ namespace xo {
xtag("lhs.iface", lhs_iface), xtag("&lhs.data", lhs_data),
xtag("rhs.iface", rhs_iface), xtag("rhs.data", rhs_data));
// see .assign_member()
mlog_store_.assign_member_aux(&gco_store_,
parent,
lhs_iface,
lhs_data,
rhs_iface,
rhs_data);
}
} /*namespace mm*/
} /*namespace xo*/

40
src/gc/MutationLogStore.cpp
View file

@ -139,17 +139,31 @@ namespace xo {
} /*verify_ok*/
void
MutationLogStore::assign_member(GCObjectStore * gco_store,
void * parent,
obj<AGCObject> * p_lhs,
obj<AGCObject> rhs)
MutationLogStore::assign_member_aux(GCObjectStore * gco_store,
void * parent,
AGCObject * lhs_iface,
void ** lhs_addr,
AGCObject * rhs_iface,
void * rhs_data)
{
scope log(XO_DEBUG(config_.debug_flag_),
xtag("parent", parent), xtag("lhs", p_lhs), xtag("rhs", rhs.data()));
xtag("parent", parent),
xtag("lhs.iface", lhs_iface),
xtag("&lhs.data", lhs_addr),
xtag("rhs.iface", rhs_iface),
xtag("rhs.data", rhs_data));
// ++ stats.n_mutation_;
*p_lhs = rhs;
assert(parent);
assert(lhs_addr);
assert(rhs_iface);
assert(rhs_data);
if (lhs_iface)
*lhs_iface = *rhs_iface;
*lhs_addr = rhs_data;
if (!config_.enabled_flag_) {
log && log(xtag("msg", "noop b/c incremental gc disabled"));
@ -162,7 +176,7 @@ namespace xo {
// 1. generation of lhs
// 2. generation of rhs
Generation src_g = gco_store->generation_of(Role::to_space(), p_lhs);
Generation src_g = gco_store->generation_of(Role::to_space(), lhs_addr);
if (src_g.is_sentinel()) {
log && log(xtag("msg", "noop because src not gc-owned"));
@ -172,7 +186,7 @@ namespace xo {
return;
}
Generation dest_g = gco_store->generation_of(Role::to_space(), rhs.data());
Generation dest_g = gco_store->generation_of(Role::to_space(), rhs_data);
if (dest_g.is_sentinel()) {
log && log(xtag("msg", "noop because dest not gc-owned"));
@ -197,7 +211,7 @@ namespace xo {
const DArena * arena = gco_store->get_space(Role::to_space(), src_g);
const DArena::header_type * src_hdr = arena->obj2hdr(parent);
const DArena::header_type * dest_hdr = arena->obj2hdr(rhs.data());
const DArena::header_type * dest_hdr = arena->obj2hdr(rhs_data);
assert(src_hdr && dest_hdr);
@ -222,16 +236,16 @@ namespace xo {
// control here: we have an older->younger pointer, need to log it
void ** lhs_addr = reinterpret_cast<void **>(&(p_lhs->data_));
obj<AGCObject> snap(rhs_iface, rhs_data);
this->_append_mutation(dest_g, parent, lhs_addr, rhs);
this->_append_mutation(dest_g, parent, lhs_addr, snap);
}
void
MutationLogStore::_append_mutation(Generation dest_g,
void * parent,
void ** addr,
obj<AGCObject> rhs)
obj<AGCObject> snap)
{
// mlog keyed by generation in which pointer _destination_ resides:
// collection that moves destination generation around needs to also
@ -239,7 +253,7 @@ namespace xo {
//
MutationLog * mlog = this->mlog_[Role::to_space()][dest_g];
mlog->push_back(MutationLogEntry(parent, addr, rhs));
mlog->push_back(MutationLogEntry(parent, addr, snap));
}
void

7
utest/DMockCollector.cpp
View file

@ -91,7 +91,12 @@ namespace xo {
void
DMockCollector::assign_member(void * parent, obj<AGCObject> * p_lhs, obj<AGCObject> & rhs)
{
mls_->assign_member(gcos_, parent, p_lhs, rhs);
mls_->assign_member_aux(gcos_,
parent,
p_lhs->iface(),
p_lhs->opaque_data_addr(),
rhs.iface(),
rhs.opaque_data());
}
void *