llvm/llvm/lib/CodeGen/MIRFSDiscriminator.cpp

//===-------- MIRFSDiscriminator.cpp: Flow Sensitive Discriminator --------===//
//
// 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 provides the implementation of a machine pass that adds the flow
// sensitive discriminator to the instruction debug information.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/MIRFSDiscriminator.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PseudoProbe.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/xxhash.h"
#include "llvm/Transforms/Utils/SampleProfileLoaderBaseUtil.h"

usingnamespacellvm;
usingnamespacesampleprof;
usingnamespacesampleprofutil;

#define DEBUG_TYPE …

// TODO(xur): Remove this option and related code once we make true as the
// default.
namespace llvm {
cl::opt<bool> ImprovedFSDiscriminator(
    "improved-fs-discriminator", cl::Hidden, cl::init(false),
    cl::desc("New FS discriminators encoding (incompatible with the original "
             "encoding)"));
}

char MIRAddFSDiscriminators::ID = …;

INITIALIZE_PASS(…)

char &llvm::MIRAddFSDiscriminatorsID = …;

FunctionPass *llvm::createMIRAddFSDiscriminatorsPass(FSDiscriminatorPass P) { … }

// TODO(xur): Remove this once we switch to ImprovedFSDiscriminator.
// Compute a hash value using debug line number, and the line numbers from the
// inline stack.
static uint64_t getCallStackHashV0(const MachineBasicBlock &BB,
                                   const MachineInstr &MI,
                                   const DILocation *DIL) { … }

static uint64_t getCallStackHash(const DILocation *DIL) { … }

// Traverse the CFG and assign FD discriminators. If two instructions
// have the same lineno and discriminator, but residing in different BBs,
// the latter instruction will get a new discriminator value. The new
// discriminator keeps the existing discriminator value but sets new bits
// b/w LowBit and HighBit.
bool MIRAddFSDiscriminators::runOnMachineFunction(MachineFunction &MF) { … }