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Type key hash tweaks. (#61234)
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* use HashTypeKey(), remove ComputeHash()

* nonrecursive HashTypeHandle

* remove instrumentation from pendingload.cpp

* two more uses of `ComputeHash()`

* Make GCC happy

* couple tweaks

* unnecessary full fences.
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@VSadov
VSadov authored Nov 8, 2021
1 parent 2266376 commit 97ce13d
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Showing 8 changed files with 38 additions and 77 deletions.
2 changes: 1 addition & 1 deletion src/coreclr/vm/clsload.cpp
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Expand Up @@ -3634,7 +3634,7 @@ ClassLoader::LoadTypeHandleForTypeKey_Body(
}
EX_HOOK
{
LOG((LF_CLASSLOADER, LL_INFO10, "Caught an exception loading: %x, %0x (Module)\n", pTypeKey->IsConstructed() ? pTypeKey->ComputeHash() : pTypeKey->GetTypeToken(), pTypeKey->GetModule()));
LOG((LF_CLASSLOADER, LL_INFO10, "Caught an exception loading: %x, %0x (Module)\n", pTypeKey->IsConstructed() ? HashTypeKey(pTypeKey) : pTypeKey->GetTypeToken(), pTypeKey->GetModule()));

if (!GetThread()->HasThreadStateNC(Thread::TSNC_LoadsTypeViolation))
{
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12 changes: 4 additions & 8 deletions src/coreclr/vm/dacenumerablehash.inl
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Expand Up @@ -135,11 +135,9 @@ void DacEnumerableHashTable<DAC_ENUM_HASH_ARGS>::BaseInsertEntry(DacEnumerableHa
// Prepare to link the new entry at the head of the bucket chain.
pVolatileEntry->m_pNextEntry = (GetBuckets())[dwBucket];

// Make sure that all writes to the entry are visible before publishing the entry.
MemoryBarrier();

// Publish the entry by pointing the bucket at it.
(GetBuckets())[dwBucket] = pVolatileEntry;
// Make sure that all writes to the entry are visible before publishing the entry.
VolatileStore(&(GetBuckets())[dwBucket], pVolatileEntry);

m_cEntries++;

Expand Down Expand Up @@ -207,15 +205,13 @@ void DacEnumerableHashTable<DAC_ENUM_HASH_ARGS>::GrowTable()
}

// Make sure that all writes are visible before publishing the new array.
MemoryBarrier();
m_pBuckets = pNewBuckets;
VolatileStore(&m_pBuckets, pNewBuckets);

// The new number of buckets has to be published last (prior to this readers may miscalculate a bucket
// index, but the result will always be in range and they'll simply walk the wrong chain and get a miss,
// prompting a retry under the lock). If we let the count become visible unordered wrt to the bucket array
// itself a reader could potentially read buckets from beyond the end of the old bucket list).
MemoryBarrier();
m_cBuckets = cNewBuckets;
VolatileStore(&m_cBuckets, cNewBuckets);
}

// Returns the next prime larger (or equal to) than the number given.
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2 changes: 1 addition & 1 deletion src/coreclr/vm/gdbjit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -387,7 +387,7 @@ class NotifyGdb
static count_t Hash(key_t k)
{
LIMITED_METHOD_CONTRACT;
return k->ComputeHash();
return HashTypeKey(k);
}

static const element_t Null() { LIMITED_METHOD_CONTRACT; return element_t(key_t(),VALUE()); }
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7 changes: 3 additions & 4 deletions src/coreclr/vm/pendingload.cpp
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Expand Up @@ -114,7 +114,7 @@ BOOL PendingTypeLoadTable::InsertValue(PendingTypeLoadEntry *pData)

_ASSERTE(m_dwNumBuckets != 0);

DWORD dwHash = pData->GetTypeKey().ComputeHash();
DWORD dwHash = HashTypeKey(&pData->GetTypeKey());
DWORD dwBucket = dwHash % m_dwNumBuckets;
PendingTypeLoadTable::TableEntry * pNewEntry = AllocNewEntry();
if (pNewEntry == NULL)
Expand All @@ -130,7 +130,6 @@ BOOL PendingTypeLoadTable::InsertValue(PendingTypeLoadEntry *pData)
return TRUE;
}


BOOL PendingTypeLoadTable::DeleteValue(TypeKey *pKey)
{
CONTRACTL
Expand All @@ -145,7 +144,7 @@ BOOL PendingTypeLoadTable::DeleteValue(TypeKey *pKey)

_ASSERTE(m_dwNumBuckets != 0);

DWORD dwHash = pKey->ComputeHash();
DWORD dwHash = HashTypeKey(pKey);
DWORD dwBucket = dwHash % m_dwNumBuckets;
PendingTypeLoadTable::TableEntry * pSearch;
PendingTypeLoadTable::TableEntry **ppPrev = &m_pBuckets[dwBucket];
Expand Down Expand Up @@ -182,7 +181,7 @@ PendingTypeLoadTable::TableEntry *PendingTypeLoadTable::FindItem(TypeKey *pKey)
_ASSERTE(m_dwNumBuckets != 0);


DWORD dwHash = pKey->ComputeHash();
DWORD dwHash = HashTypeKey(pKey);
DWORD dwBucket = dwHash % m_dwNumBuckets;
PendingTypeLoadTable::TableEntry * pSearch;

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2 changes: 1 addition & 1 deletion src/coreclr/vm/pendingload.h
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Original file line number Diff line number Diff line change
Expand Up @@ -166,7 +166,7 @@ class PendingTypeLoadEntry
}
#endif //DACCESS_COMPILE

TypeKey GetTypeKey()
TypeKey& GetTypeKey()
{
LIMITED_METHOD_CONTRACT;
return m_typeKey;
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60 changes: 26 additions & 34 deletions src/coreclr/vm/typehash.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -141,10 +141,10 @@ DWORD EETypeHashTable::GetCount()
return BaseGetElementCount();
}

static DWORD HashTypeHandle(DWORD level, TypeHandle t);
static DWORD HashTypeHandle(TypeHandle t);

// Calculate hash value for a type def or instantiated type def
static DWORD HashPossiblyInstantiatedType(DWORD level, mdTypeDef token, Instantiation inst)
static DWORD HashPossiblyInstantiatedType(mdTypeDef token, Instantiation inst)
{
CONTRACTL
{
Expand All @@ -161,25 +161,18 @@ static DWORD HashPossiblyInstantiatedType(DWORD level, mdTypeDef token, Instanti
dwHash = ((dwHash << 5) + dwHash) ^ token;
if (!inst.IsEmpty())
{
dwHash = ((dwHash << 5) + dwHash) ^ inst.GetNumArgs();

// Hash two levels of the hiearchy. A simple nesting of generics instantiations is
// pretty common in generic collections, e.g.: ICollection<KeyValuePair<TKey, TValue>>
if (level < 2)
// Hash n type parameters
for (DWORD i = 0; i < inst.GetNumArgs(); i++)
{
// Hash n type parameters
for (DWORD i = 0; i < inst.GetNumArgs(); i++)
{
dwHash = ((dwHash << 5) + dwHash) ^ HashTypeHandle(level+1, inst[i]);
}
dwHash = ((dwHash << 5) + dwHash) ^ inst[i].AsTAddr();
}
}

return dwHash;
}

// Calculate hash value for a function pointer type
static DWORD HashFnPtrType(DWORD level, BYTE callConv, DWORD numArgs, TypeHandle *retAndArgTypes)
static DWORD HashFnPtrType(BYTE callConv, DWORD numArgs, TypeHandle *retAndArgTypes)
{
WRAPPER_NO_CONTRACT;
SUPPORTS_DAC;
Expand All @@ -188,31 +181,29 @@ static DWORD HashFnPtrType(DWORD level, BYTE callConv, DWORD numArgs, TypeHandle
dwHash = ((dwHash << 5) + dwHash) ^ ELEMENT_TYPE_FNPTR;
dwHash = ((dwHash << 5) + dwHash) ^ callConv;
dwHash = ((dwHash << 5) + dwHash) ^ numArgs;
if (level < 1)

for (DWORD i = 0; i <= numArgs; i++)
{
for (DWORD i = 0; i <= numArgs; i++)
{
dwHash = ((dwHash << 5) + dwHash) ^ HashTypeHandle(level+1, retAndArgTypes[i]);
}
dwHash = ((dwHash << 5) + dwHash) ^ retAndArgTypes[i].AsTAddr();
}

return dwHash;
}

// Calculate hash value for an array/pointer/byref type
static DWORD HashParamType(DWORD level, CorElementType kind, TypeHandle typeParam)
static DWORD HashParamType(CorElementType kind, TypeHandle typeParam)
{
WRAPPER_NO_CONTRACT;
INT_PTR dwHash = 5381;

dwHash = ((dwHash << 5) + dwHash) ^ kind;
dwHash = ((dwHash << 5) + dwHash) ^ HashTypeHandle(level, typeParam);
dwHash = ((dwHash << 5) + dwHash) ^ typeParam.AsTAddr();

return dwHash;
}

// Calculate hash value from type handle
static DWORD HashTypeHandle(DWORD level, TypeHandle t)
static DWORD HashTypeHandle(TypeHandle t)
{
CONTRACTL
{
Expand All @@ -229,29 +220,30 @@ static DWORD HashTypeHandle(DWORD level, TypeHandle t)

if (t.HasTypeParam())
{
retVal = HashParamType(level, t.GetInternalCorElementType(), t.GetTypeParam());
}
else if (t.IsGenericVariable())
{
retVal = (dac_cast<PTR_TypeVarTypeDesc>(t.AsTypeDesc())->GetToken());
retVal = HashParamType(t.GetInternalCorElementType(), t.GetTypeParam());
}
else if (t.HasInstantiation())
{
retVal = HashPossiblyInstantiatedType(level, t.GetCl(), t.GetInstantiation());
retVal = HashPossiblyInstantiatedType(t.GetCl(), t.GetInstantiation());
}
else if (t.IsFnPtrType())
{
FnPtrTypeDesc* pTD = t.AsFnPtrType();
retVal = HashFnPtrType(level, pTD->GetCallConv(), pTD->GetNumArgs(), pTD->GetRetAndArgTypesPointer());
retVal = HashFnPtrType(pTD->GetCallConv(), pTD->GetNumArgs(), pTD->GetRetAndArgTypesPointer());
}
else if (t.IsGenericVariable())
{
_ASSERTE(!"Generic variables are unexpected here.");
retVal = t.AsTAddr();
}
else
retVal = HashPossiblyInstantiatedType(level, t.GetCl(), Instantiation());
retVal = HashPossiblyInstantiatedType(t.GetCl(), Instantiation());

return retVal;
}

// Calculate hash value from key
static DWORD HashTypeKey(TypeKey* pKey)
DWORD HashTypeKey(TypeKey* pKey)
{
CONTRACTL
{
Expand All @@ -265,15 +257,15 @@ static DWORD HashTypeKey(TypeKey* pKey)

if (pKey->GetKind() == ELEMENT_TYPE_CLASS)
{
return HashPossiblyInstantiatedType(0, pKey->GetTypeToken(), pKey->GetInstantiation());
return HashPossiblyInstantiatedType(pKey->GetTypeToken(), pKey->GetInstantiation());
}
else if (pKey->GetKind() == ELEMENT_TYPE_FNPTR)
{
return HashFnPtrType(0, pKey->GetCallConv(), pKey->GetNumArgs(), pKey->GetRetAndArgTypes());
return HashFnPtrType(pKey->GetCallConv(), pKey->GetNumArgs(), pKey->GetRetAndArgTypes());
}
else
{
return HashParamType(0, pKey->GetKind(), pKey->GetElementType());
return HashParamType(pKey->GetKind(), pKey->GetElementType());
}
}

Expand Down Expand Up @@ -552,7 +544,7 @@ VOID EETypeHashTable::InsertValue(TypeHandle data)

pNewEntry->SetTypeHandle(data);

BaseInsertEntry(HashTypeHandle(0, data), pNewEntry);
BaseInsertEntry(HashTypeHandle(data), pNewEntry);
}

#endif // #ifndef DACCESS_COMPILE
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2 changes: 2 additions & 0 deletions src/coreclr/vm/typehash.h
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,8 @@
//
//========================================================================================

DWORD HashTypeKey(TypeKey* pKey);

// One of these is present for each element in the table
// It simply chains together (hash,data) pairs
typedef DPTR(struct EETypeHashEntry) PTR_EETypeHashEntry;
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28 changes: 0 additions & 28 deletions src/coreclr/vm/typekey.h
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Original file line number Diff line number Diff line change
Expand Up @@ -213,7 +213,6 @@ class TypeKey
return TypeKey::Equals(this, pKey);
}

// Comparison and hashing
static BOOL Equals(const TypeKey *pKey1, const TypeKey *pKey2)
{
WRAPPER_NO_CONTRACT;
Expand Down Expand Up @@ -257,33 +256,6 @@ class TypeKey
return TRUE;
}
}

DWORD ComputeHash() const
{
LIMITED_METHOD_CONTRACT;
DWORD_PTR hashLarge;

if (m_kind == ELEMENT_TYPE_CLASS)
{
hashLarge = ((DWORD_PTR)u.asClass.m_pModule ^ (DWORD_PTR)u.asClass.m_numGenericArgs ^ (DWORD_PTR)u.asClass.m_typeDef);
}
else if (CorTypeInfo::IsModifier_NoThrow(m_kind) || m_kind == ELEMENT_TYPE_VALUETYPE)
{
hashLarge = (u.asParamType.m_paramType ^ (DWORD_PTR) u.asParamType.m_rank);
}
else hashLarge = 0;

#if POINTER_BITS == 32
return hashLarge;
#else
DWORD hash = *(DWORD *)&hashLarge;
for (unsigned i = 1; i < POINTER_BITS / 32; i++)
{
hash ^= ((DWORD *)&hashLarge)[i];
}
return hash;
#endif
}
};


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