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Improve the hash function used in the InstMethodHashTable #94938

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Merged
merged 1 commit into from
Nov 18, 2023
Merged

Improve the hash function used in the InstMethodHashTable #94938

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25 changes: 7 additions & 18 deletions src/coreclr/vm/instmethhash.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -96,30 +96,19 @@ static DWORD Hash(TypeHandle declaringType, mdMethodDef token, Instantiation ins

DWORD dwHash = 0x87654321;
#define INST_HASH_ADD(_value) dwHash = ((dwHash << 5) + dwHash) ^ (_value)
#ifdef TARGET_64BIT
#define INST_HASH_ADDPOINTER(_value) INST_HASH_ADD((uint32_t)(uintptr_t)_value); INST_HASH_ADD((uint32_t)(((uintptr_t)_value) >> 32))
#else
#define INST_HASH_ADDPOINTER(_value) INST_HASH_ADD((uint32_t)(uintptr_t)_value);
#endif

INST_HASH_ADD(declaringType.GetCl());
INST_HASH_ADDPOINTER(declaringType.AsPtr());
INST_HASH_ADD(token);

for (DWORD i = 0; i < inst.GetNumArgs(); i++)
{
TypeHandle thArg = inst[i];

if (thArg.GetMethodTable())
{
INST_HASH_ADD(thArg.GetCl());

Instantiation sArgInst = thArg.GetInstantiation();
for (DWORD j = 0; j < sArgInst.GetNumArgs(); j++)
{
TypeHandle thSubArg = sArgInst[j];
if (thSubArg.GetMethodTable())
INST_HASH_ADD(thSubArg.GetCl());
else
INST_HASH_ADD(thSubArg.GetSignatureCorElementType());
}
}
else
INST_HASH_ADD(thArg.GetSignatureCorElementType());
INST_HASH_ADDPOINTER(thArg.AsPtr());
}

return dwHash;
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