llvm/lib/CodeGen/MachineStableHash.cpp

   1 //===- lib/CodeGen/MachineStableHash.cpp ----------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Stable hashing for MachineInstr and MachineOperand. Useful or getting a
  10 // hash across runs, modules, etc.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/CodeGen/MachineStableHash.h"
  15 #include "llvm/ADT/FoldingSet.h"
  16 #include "llvm/ADT/Statistic.h"
  17 #include "llvm/ADT/StringExtras.h"
  18 #include "llvm/Analysis/Loads.h"
  19 #include "llvm/Analysis/MemoryLocation.h"
  20 #include "llvm/CodeGen/MIRFormatter.h"
  21 #include "llvm/CodeGen/MIRPrinter.h"
  22 #include "llvm/CodeGen/MachineFrameInfo.h"
  23 #include "llvm/CodeGen/MachineInstr.h"
  24 #include "llvm/CodeGen/MachineJumpTableInfo.h"
  25 #include "llvm/CodeGen/MachineOperand.h"
  26 #include "llvm/CodeGen/MachineRegisterInfo.h"
  27 #include "llvm/CodeGen/StableHashing.h"
  28 #include "llvm/CodeGen/TargetInstrInfo.h"
  29 #include "llvm/CodeGen/TargetRegisterInfo.h"
  30 #include "llvm/Config/llvm-config.h"
  31 #include "llvm/IR/Constants.h"
  32 #include "llvm/IR/IRPrintingPasses.h"
  33 #include "llvm/IR/Instructions.h"
  34 #include "llvm/IR/ModuleSlotTracker.h"
  35 #include "llvm/MC/MCDwarf.h"
  36 #include "llvm/Target/TargetIntrinsicInfo.h"
  37 #include "llvm/Target/TargetMachine.h"
  38
  39 #define DEBUG_TYPE "machine-stable-hash"
  40
  41 using namespace llvm;
  42
  43 STATISTIC(StableHashBailingMachineBasicBlock,
  44           "Number of encountered unsupported MachineOperands that were "
  45           "MachineBasicBlocks while computing stable hashes");
  46 STATISTIC(StableHashBailingConstantPoolIndex,
  47           "Number of encountered unsupported MachineOperands that were "
  48           "ConstantPoolIndex while computing stable hashes");
  49 STATISTIC(StableHashBailingTargetIndexNoName,
  50           "Number of encountered unsupported MachineOperands that were "
  51           "TargetIndex with no name");
  52 STATISTIC(StableHashBailingGlobalAddress,
  53           "Number of encountered unsupported MachineOperands that were "
  54           "GlobalAddress while computing stable hashes");
  55 STATISTIC(StableHashBailingBlockAddress,
  56           "Number of encountered unsupported MachineOperands that were "
  57           "BlockAddress while computing stable hashes");
  58 STATISTIC(StableHashBailingMetadataUnsupported,
  59           "Number of encountered unsupported MachineOperands that were "
  60           "Metadata of an unsupported kind while computing stable hashes");
  61
  62 stable_hash llvm::stableHashValue(const MachineOperand &MO) {
  63   switch (MO.getType()) {
  64   case MachineOperand::MO_Register:
  65     if (Register::isVirtualRegister(MO.getReg())) {
  66       const MachineRegisterInfo &MRI = MO.getParent()->getMF()->getRegInfo();
  67       return MRI.getVRegDef(MO.getReg())->getOpcode();
  68     }
  69
  70     // Register operands don't have target flags.
  71     return stable_hash_combine(MO.getType(), MO.getReg(), MO.getSubReg(),
  72                                MO.isDef());
  73   case MachineOperand::MO_Immediate:
  74     return stable_hash_combine(MO.getType(), MO.getTargetFlags(), MO.getImm());
  75   case MachineOperand::MO_CImmediate:
  76   case MachineOperand::MO_FPImmediate: {
  77     auto Val = MO.isCImm() ? MO.getCImm()->getValue()
  78                            : MO.getFPImm()->getValueAPF().bitcastToAPInt();
  79     auto ValHash =
  80         stable_hash_combine_array(Val.getRawData(), Val.getNumWords());
  81     return hash_combine(MO.getType(), MO.getTargetFlags(), ValHash);
  82   }
  83
  84   case MachineOperand::MO_MachineBasicBlock:
  85     StableHashBailingMachineBasicBlock++;
  86     return 0;
  87   case MachineOperand::MO_ConstantPoolIndex:
  88     StableHashBailingConstantPoolIndex++;
  89     return 0;
  90   case MachineOperand::MO_BlockAddress:
  91     StableHashBailingBlockAddress++;
  92     return 0;
  93   case MachineOperand::MO_Metadata:
  94     StableHashBailingMetadataUnsupported++;
  95     return 0;
  96   case MachineOperand::MO_GlobalAddress:
  97     StableHashBailingGlobalAddress++;
  98     return 0;
  99   case MachineOperand::MO_TargetIndex: {
 100     if (const char *Name = MO.getTargetIndexName())
 101       return stable_hash_combine(MO.getType(), MO.getTargetFlags(),
 102                                  stable_hash_combine_string(Name),
 103                                  MO.getOffset());
 104     StableHashBailingTargetIndexNoName++;
 105     return 0;
 106   }
 107
 108   case MachineOperand::MO_FrameIndex:
 109   case MachineOperand::MO_JumpTableIndex:
 110     return stable_hash_combine(MO.getType(), MO.getTargetFlags(),
 111                                MO.getIndex());
 112
 113   case MachineOperand::MO_ExternalSymbol:
 114     return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getOffset(),
 115                         stable_hash_combine_string(MO.getSymbolName()));
 116
 117   case MachineOperand::MO_RegisterMask:
 118   case MachineOperand::MO_RegisterLiveOut:
 119     return hash_combine(MO.getType(), MO.getTargetFlags(), MO.getRegMask());
 120
 121   case MachineOperand::MO_ShuffleMask: {
 122     std::vector<llvm::stable_hash> ShuffleMaskHashes;
 123
 124     llvm::transform(
 125         MO.getShuffleMask(), std::back_inserter(ShuffleMaskHashes),
 126         [](int S) -> llvm::stable_hash { return llvm::stable_hash(S); });
 127
 128     return hash_combine(MO.getType(), MO.getTargetFlags(),
 129                         stable_hash_combine_array(ShuffleMaskHashes.data(),
 130                                                   ShuffleMaskHashes.size()));
 131   }
 132   case MachineOperand::MO_MCSymbol: {
 133     auto SymbolName = MO.getMCSymbol()->getName();
 134     return hash_combine(MO.getType(), MO.getTargetFlags(),
 135                         stable_hash_combine_string(SymbolName));
 136   }
 137   case MachineOperand::MO_CFIIndex:
 138     return stable_hash_combine(MO.getType(), MO.getTargetFlags(),
 139                                MO.getCFIIndex());
 140   case MachineOperand::MO_IntrinsicID:
 141     return stable_hash_combine(MO.getType(), MO.getTargetFlags(),
 142                                MO.getIntrinsicID());
 143   case MachineOperand::MO_Predicate:
 144     return stable_hash_combine(MO.getType(), MO.getTargetFlags(),
 145                                MO.getPredicate());
 146   }
 147   llvm_unreachable("Invalid machine operand type");
 148 }
 149
 150 /// A stable hash value for machine instructions.
 151 /// Returns 0 if no stable hash could be computed.
 152 /// The hashing and equality testing functions ignore definitions so this is
 153 /// useful for CSE, etc.
 154 stable_hash llvm::stableHashValue(const MachineInstr &MI, bool HashVRegs,
 155                                   bool HashConstantPoolIndices,
 156                                   bool HashMemOperands) {
 157   // Build up a buffer of hash code components.
 158   SmallVector<stable_hash, 16> HashComponents;
 159   HashComponents.reserve(MI.getNumOperands() + MI.getNumMemOperands() + 2);
 160   HashComponents.push_back(MI.getOpcode());
 161   HashComponents.push_back(MI.getFlags());
 162   for (const MachineOperand &MO : MI.operands()) {
 163     if (!HashVRegs && MO.isReg() && MO.isDef() &&
 164         Register::isVirtualRegister(MO.getReg()))
 165       continue; // Skip virtual register defs.
 166
 167     if (MO.isCPI()) {
 168       HashComponents.push_back(stable_hash_combine(
 169           MO.getType(), MO.getTargetFlags(), MO.getIndex()));
 170       continue;
 171     }
 172
 173     stable_hash StableHash = stableHashValue(MO);
 174     if (!StableHash)
 175       return 0;
 176     HashComponents.push_back(StableHash);
 177   }
 178
 179   for (const auto *Op : MI.memoperands()) {
 180     if (!HashMemOperands)
 181       break;
 182     HashComponents.push_back(static_cast<unsigned>(Op->getSize()));
 183     HashComponents.push_back(static_cast<unsigned>(Op->getFlags()));
 184     HashComponents.push_back(static_cast<unsigned>(Op->getOffset()));
 185     HashComponents.push_back(static_cast<unsigned>(Op->getSuccessOrdering()));
 186     HashComponents.push_back(static_cast<unsigned>(Op->getAddrSpace()));
 187     HashComponents.push_back(static_cast<unsigned>(Op->getSyncScopeID()));
 188     HashComponents.push_back(static_cast<unsigned>(Op->getBaseAlign().value()));
 189     HashComponents.push_back(static_cast<unsigned>(Op->getFailureOrdering()));
 190   }
 191
 192   return stable_hash_combine_range(HashComponents.begin(),
 193                                    HashComponents.end());
 194 }