llvm/llvm/lib/Target/AArch64/AArch64CompressJumpTables.cpp

//==-- AArch64CompressJumpTables.cpp - Compress jump tables for AArch64 --====//
//
// 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 pass looks at the basic blocks each jump-table refers to and works out
// whether they can be emitted in a compressed form (with 8 or 16-bit
// entries). If so, it changes the opcode and flags them in the associated
// AArch64FunctionInfo.
//
//===----------------------------------------------------------------------===//

#include "AArch64.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64Subtarget.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/Debug.h"

usingnamespacellvm;

#define DEBUG_TYPE …

STATISTIC(NumJT8, "Number of jump-tables with 1-byte entries");
STATISTIC(NumJT16, "Number of jump-tables with 2-byte entries");
STATISTIC(NumJT32, "Number of jump-tables with 4-byte entries");

namespace {
class AArch64CompressJumpTables : public MachineFunctionPass { … };
char AArch64CompressJumpTables::ID = …;
} // namespace

INITIALIZE_PASS(…)

std::optional<int>
AArch64CompressJumpTables::computeBlockSize(MachineBasicBlock &MBB) { … }

bool AArch64CompressJumpTables::scanFunction() { … }

bool AArch64CompressJumpTables::compressJumpTable(MachineInstr &MI,
                                                  int Offset) { … }

bool AArch64CompressJumpTables::runOnMachineFunction(MachineFunction &MFIn) { … }

FunctionPass *llvm::createAArch64CompressJumpTablesPass() { … }