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shared_ptrify ownershp of PoolEntries in PBQP's CostPool

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Leveraging both intrusive shared_ptr-ing (std::enable_shared_from_this)
and shared_ptr<T>-owning-U (to allow external users to hold
std::shared_ptr<CostT> while keeping the underlying PoolEntry alive).

The intrusiveness could be removed if we had a weak_set that implicitly
removed items from the set when their underlying data went away.

This /might/ fix an existing memory leak reported by LeakSanitizer in
r217504.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217563 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Blaikie 2014-09-10 23:54:45 +00:00
parent 5ee5d45e7e
commit c6b38ee178
1 changed files with 10 additions and 46 deletions
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56
include/llvm/CodeGen/PBQP/CostAllocator.h
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@ -18,6 +18,7 @@
#ifndef LLVM_CODEGEN_PBQP_COSTALLOCATOR_H
#define LLVM_CODEGEN_PBQP_COSTALLOCATOR_H
#include <memory>
#include <set>
#include <type_traits>
@ -27,57 +28,20 @@ template <typename CostT,
typename CostKeyTComparator>
class CostPool {
public:
class PoolEntry {
class PoolEntry : public std::enable_shared_from_this<PoolEntry> {
public:
template <typename CostKeyT>
PoolEntry(CostPool &pool, CostKeyT cost)
: pool(pool), cost(std::move(cost)), refCount(0) {}
: pool(pool), cost(std::move(cost)) {}
~PoolEntry() { pool.removeEntry(this); }
void incRef() { ++refCount; }
bool decRef() { --refCount; return (refCount == 0); }
CostT& getCost() { return cost; }
const CostT& getCost() const { return cost; }
private:
CostPool &pool;
CostT cost;
std::size_t refCount;
};
class PoolRef {
public:
PoolRef(PoolEntry *entry) : entry(entry) {
this->entry->incRef();
}
PoolRef(const PoolRef &r) {
entry = r.entry;
entry->incRef();
}
PoolRef& operator=(const PoolRef &r) {
assert(entry != nullptr && "entry should not be null.");
PoolEntry *temp = r.entry;
temp->incRef();
entry->decRef();
entry = temp;
return *this;
}
~PoolRef() {
if (entry->decRef())
delete entry;
}
void reset(PoolEntry *entry) {
entry->incRef();
this->entry->decRef();
this->entry = entry;
}
CostT& operator*() { return entry->getCost(); }
const CostT& operator*() const { return entry->getCost(); }
CostT* operator->() { return &entry->getCost(); }
const CostT* operator->() const { return &entry->getCost(); }
private:
PoolEntry *entry;
};
typedef std::shared_ptr<CostT> PoolRef;
private:
class EntryComparator {
@ -104,19 +68,19 @@ private:
void removeEntry(PoolEntry *p) { entrySet.erase(p); }
public:
template <typename CostKeyT>
PoolRef getCost(CostKeyT costKey) {
std::shared_ptr<CostT> getCost(CostKeyT costKey) {
typename EntrySet::iterator itr =
std::lower_bound(entrySet.begin(), entrySet.end(), costKey,
EntryComparator());
if (itr != entrySet.end() && costKey == (*itr)->getCost())
return PoolRef(*itr);
return std::shared_ptr<CostT>((*itr)->shared_from_this(),
&(*itr)->getCost());
PoolEntry *p = new PoolEntry(*this, std::move(costKey));
entrySet.insert(itr, p);
return PoolRef(p);
auto p = std::make_shared<PoolEntry>(*this, std::move(costKey));
entrySet.insert(itr, p.get());
return std::shared_ptr<CostT>(std::move(p), &p->getCost());
}
};