MIRFSDiscriminator.cpp Source File (original) (raw)

31using namespace llvm;

35#define DEBUG_TYPE "mirfs-discriminators"

41 cl::desc("New FS discriminators encoding (incompatible with the original "

42 "encoding)"));

46 "Add MIR Flow Sensitive Discriminators",

47 false, false)

53}

62 if (Str.empty())

63 return 0;

65 };

66 uint64_t Ret = updateHash(std::to_string(DIL->getLine()));

67 Ret ^= updateHash(BB.getName());

68 Ret ^= updateHash(DIL->getScope()->getSubprogram()->getLinkageName());

69 for (DIL = DIL->getInlinedAt(); DIL; DIL = DIL->getInlinedAt()) {

70 Ret ^= updateHash(std::to_string(DIL->getLine()));

71 Ret ^= updateHash(DIL->getScope()->getSubprogram()->getLinkageName());

72 }

73 return Ret;

74}

78 std::hash<uint64_t> Hasher;

79 return Seed ^ (Hasher(Val) + 0x9e3779b9 + (Seed << 6) + (Seed >> 2));

80 };

82 for (DIL = DIL->getInlinedAt(); DIL; DIL = DIL->getInlinedAt()) {

84 Ret = hashCombine(Ret, xxh3_64bits(DIL->getSubprogramLinkageName()));

85 }

86 return Ret;

87}

94bool MIRAddFSDiscriminators::runOnMachineFunction(MachineFunction &MF) {

96 return false;

98 bool HasPseudoProbe = MF.getFunction().getParent()->getNamedMetadata(

100

101 if (!HasPseudoProbe && !MF.getFunction().shouldEmitDebugInfoForProfiling())

102 return false;

103

105 using LocationDiscriminator =

106 std::tuple<StringRef, unsigned, unsigned, uint64_t>;

107 using BBSet = DenseSet<const MachineBasicBlock *>;

108 using LocationDiscriminatorBBMap = DenseMap<LocationDiscriminator, BBSet>;

109 using LocationDiscriminatorCurrPassMap =

110 DenseMap<LocationDiscriminator, unsigned>;

111

112 LocationDiscriminatorBBMap LDBM;

113 LocationDiscriminatorCurrPassMap LDCM;

114

115

116

117 unsigned LowBitTemp = LowBit;

118 assert(LowBit > 0 && "LowBit in FSDiscriminator cannot be 0");

120 LowBitTemp -= 1;

121 unsigned BitMaskBefore = getN1Bits(LowBitTemp);

122

123 unsigned BitMaskNow = getN1Bits(HighBit);

124

125 unsigned BitMaskThisPass = BitMaskNow ^ BitMaskBefore;

126 unsigned NumNewD = 0;

127

128 LLVM_DEBUG(dbgs() << "MIRAddFSDiscriminators working on Func: "

129 << MF.getFunction().getName() << " Highbit=" << HighBit

130 << "\n");

131

132 for (MachineBasicBlock &BB : MF) {

133 for (MachineInstr &I : BB) {

134 if (HasPseudoProbe) {

135

136

137

138 if (.isPseudoProbe())

139 continue;

141 continue;

142 }

143 const DILocation *DIL = I.getDebugLoc().get();

144 if (!DIL)

145 continue;

146

147

148 unsigned LineNo =

149 I.isPseudoProbe() ? I.getOperand(1).getImm() : DIL->getLine();

150 if (LineNo == 0)

151 continue;

152 unsigned Discriminator = DIL->getDiscriminator();

153

154

155 if ((Pass == FSDiscriminatorPass::Pass1) && I.isPseudoProbe()) {

158 }

159 uint64_t CallStackHashVal = 0;

162

163 LocationDiscriminator LD{DIL->getFilename(), LineNo, Discriminator,

164 CallStackHashVal};

165 auto &BBMap = LDBM[LD];

166 auto R = BBMap.insert(&BB);

167 if (BBMap.size() == 1)

168 continue;

169

170 unsigned DiscriminatorCurrPass;

171 DiscriminatorCurrPass = R.second ? ++LDCM[LD] : LDCM[LD];

172 DiscriminatorCurrPass = DiscriminatorCurrPass << LowBit;

175 DiscriminatorCurrPass &= BitMaskThisPass;

176 unsigned NewD = Discriminator | DiscriminatorCurrPass;

178 if (!NewDIL) {

179 LLVM_DEBUG(dbgs() << "Could not encode discriminator: "

180 << DIL->getFilename() << ":" << DIL->getLine() << ":"

181 << DIL->getColumn() << ":" << Discriminator << " "

182 << I << "\n");

183 continue;

184 }

185

186 I.setDebugLoc(NewDIL);

187 NumNewD++;

188 LLVM_DEBUG(dbgs() << DIL->getFilename() << ":" << DIL->getLine() << ":"

189 << DIL->getColumn() << ": add FS discriminator, from "

190 << Discriminator << " -> " << NewD << "\n");

192 }

193 }

194

197 LLVM_DEBUG(dbgs() << "Num of FS Discriminators: " << NumNewD << "\n");

198 (void) NumNewD;

199 }

200

202}

assert(UImm &&(UImm !=~static_cast< T >(0)) &&"Invalid immediate!")

This file defines the DenseMap class.

This file defines the DenseSet and SmallDenseSet classes.

Module.h This file contains the declarations for the Module class.

static uint64_t getCallStackHashV0(const MachineBasicBlock &BB, const MachineInstr &MI, const DILocation *DIL)

Definition MIRFSDiscriminator.cpp:58

static uint64_t getCallStackHash(const DILocation *DIL)

Definition MIRFSDiscriminator.cpp:76

#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)

static ManagedStatic< cl::opt< uint64_t >, CreateSeed > Seed

This file provides the utility functions for the sampled PGO loader base implementation.

ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...

const DILocation * cloneWithDiscriminator(unsigned Discriminator) const

Returns a new DILocation with updated Discriminator.

FunctionPass class - This class is used to implement most global optimizations.

LLVM_ABI StringRef getName() const

Return the name of the corresponding LLVM basic block, or an empty string.

Representation of each machine instruction.

StringRef - Represent a constant reference to a string, i.e.

unsigned ID

LLVM IR allows to use arbitrary numbers as calling convention identifiers.

initializer< Ty > init(const Ty &Val)

uint64_t MD5Hash(const FunctionId &Obj)

void createFSDiscriminatorVariable(Module *M)

Create a global variable to flag FSDiscriminators are used.

This is an optimization pass for GlobalISel generic memory operations.

LLVM_ABI char & MIRAddFSDiscriminatorsID

This pass adds flow sensitive discriminators.

cl::opt< bool > ImprovedFSDiscriminator

LLVM_ABI uint64_t xxh3_64bits(ArrayRef< uint8_t > data)

LLVM_ABI cl::opt< bool > EnableFSDiscriminator

LLVM_ABI FunctionPass * createMIRAddFSDiscriminatorsPass(sampleprof::FSDiscriminatorPass P)

Add Flow Sensitive Discriminators.

LLVM_ABI raw_ostream & dbgs()

dbgs() - This returns a reference to a raw_ostream for debugging messages.

static unsigned getN1Bits(int N)

constexpr const char * PseudoProbeDescMetadataName