llvm/llvm/include/llvm/Support/Discriminator.h

//===---- llvm/Support/Discriminator.h -- Discriminator Utils ---*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the constants and utility functions for discriminators.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_DISCRIMINATOR_H
#define LLVM_SUPPORT_DISCRIMINATOR_H

#include "llvm/Support/Error.h"
#include <assert.h>

// Utility functions for encoding / decoding discriminators.
/// With a given unsigned int \p U, use up to 13 bits to represent it.
/// old_bit 1~5  --> new_bit 1~5
/// old_bit 6~12 --> new_bit 7~13
/// new_bit_6 is 0 if higher bits (7~13) are all 0
static inline unsigned getPrefixEncodingFromUnsigned(unsigned U) { … }

/// Reverse transformation as getPrefixEncodingFromUnsigned.
static inline unsigned getUnsignedFromPrefixEncoding(unsigned U) { … }

/// Returns the next component stored in discriminator.
static inline unsigned getNextComponentInDiscriminator(unsigned D) { … }

static inline unsigned encodeComponent(unsigned C) { … }

static inline unsigned encodingBits(unsigned C) { … }

// Some constants used in FS Discriminators.
//
namespace llvm {
namespace sampleprof {
enum FSDiscriminatorPass { … };
} // namespace sampleprof

// The number of bits reserved for the base discrimininator. The base
// discriminaitor starts from bit 0.
static const unsigned BaseDiscriminatorBitWidth = …;

// The number of bits reserved for each FS discriminator pass.
static const unsigned FSDiscriminatorBitWidth = …;

// Return the number of FS passes, excluding the pass adding the base
// discriminators.
// The number of passes for FS discriminators. Note that the total
// number of discriminaitor bits, i.e.
// BaseDiscriminatorBitWidth
//  + FSDiscriminatorBitWidth * getNumFSPasses()
// needs to fit in an unsigned int type.
static inline unsigned getNumFSPasses() { … }

// Return the ending bit for FSPass P.
static inline unsigned getFSPassBitEnd(sampleprof::FSDiscriminatorPass P) { … }

// Return the begining bit for FSPass P.
static inline unsigned getFSPassBitBegin(sampleprof::FSDiscriminatorPass P) { … }

// Return the beginning bit for the last FSPass.
static inline int getLastFSPassBitBegin() { … }

// Return the ending bit for the last FSPass.
static inline unsigned getLastFSPassBitEnd() { … }

// Return the beginning bit for the base (first) FSPass.
static inline unsigned getBaseFSBitBegin() { … }

// Return the ending bit for the base (first) FSPass.
static inline unsigned getBaseFSBitEnd() { … }

// Set bits in range of [0 .. n] to 1. Used in FS Discriminators.
static inline unsigned getN1Bits(int N) { … }

} // namespace llvm

#endif /* LLVM_SUPPORT_DISCRIMINATOR_H */