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//===- AllocToken.cpp - Allocation Token Calculation ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Definition of AllocToken modes and shared calculation of stateless token IDs.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/AllocToken.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SipHash.h"
using namespace llvm;
std::optional<AllocTokenMode>
llvm::getAllocTokenModeFromString(StringRef Name) {
return StringSwitch<std::optional<AllocTokenMode>>(Name)
.Case("increment", AllocTokenMode::Increment)
.Case("random", AllocTokenMode::Random)
.Case("typehash", AllocTokenMode::TypeHash)
.Case("typehashpointersplit", AllocTokenMode::TypeHashPointerSplit)
.Default(std::nullopt);
}
static uint64_t getStableHash(const AllocTokenMetadata &Metadata,
uint64_t MaxTokens) {
return getStableSipHash(Metadata.TypeName) % MaxTokens;
}
std::optional<uint64_t> llvm::getAllocToken(AllocTokenMode Mode,
const AllocTokenMetadata &Metadata,
uint64_t MaxTokens) {
assert(MaxTokens && "Must provide non-zero max tokens");
switch (Mode) {
case AllocTokenMode::Increment:
case AllocTokenMode::Random:
// Stateful modes cannot be implemented as a pure function.
return std::nullopt;
case AllocTokenMode::TypeHash:
return getStableHash(Metadata, MaxTokens);
case AllocTokenMode::TypeHashPointerSplit: {
if (MaxTokens == 1)
return 0;
const uint64_t HalfTokens = MaxTokens / 2;
uint64_t Hash = getStableHash(Metadata, HalfTokens);
if (Metadata.ContainsPointer)
Hash += HalfTokens;
return Hash;
}
}
llvm_unreachable("");
}
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