include/llvm/CodeGen/MachineInstrBundle.h

   1 //===- llvm/CodeGen/MachineInstrBundle.h - MI bundle utilities --*- C++ -*-===//
   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 // This file provide utility functions to manipulate machine instruction
  10 // bundles.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_CODEGEN_MACHINEINSTRBUNDLE_H
  15 #define LLVM_CODEGEN_MACHINEINSTRBUNDLE_H
  16
  17 #include "llvm/CodeGen/MachineBasicBlock.h"
  18
  19 namespace llvm {
  20
  21 /// finalizeBundle - Finalize a machine instruction bundle which includes
  22 /// a sequence of instructions starting from FirstMI to LastMI (exclusive).
  23 /// This routine adds a BUNDLE instruction to represent the bundle, it adds
  24 /// IsInternalRead markers to MachineOperands which are defined inside the
  25 /// bundle, and it copies externally visible defs and uses to the BUNDLE
  26 /// instruction.
  27 void finalizeBundle(MachineBasicBlock &MBB,
  28                     MachineBasicBlock::instr_iterator FirstMI,
  29                     MachineBasicBlock::instr_iterator LastMI);
  30
  31 /// finalizeBundle - Same functionality as the previous finalizeBundle except
  32 /// the last instruction in the bundle is not provided as an input. This is
  33 /// used in cases where bundles are pre-determined by marking instructions
  34 /// with 'InsideBundle' marker. It returns the MBB instruction iterator that
  35 /// points to the end of the bundle.
  36 MachineBasicBlock::instr_iterator finalizeBundle(MachineBasicBlock &MBB,
  37                     MachineBasicBlock::instr_iterator FirstMI);
  38
  39 /// finalizeBundles - Finalize instruction bundles in the specified
  40 /// MachineFunction. Return true if any bundles are finalized.
  41 bool finalizeBundles(MachineFunction &MF);
  42
  43 /// Returns an iterator to the first instruction in the bundle containing \p I.
  44 inline MachineBasicBlock::instr_iterator getBundleStart(
  45     MachineBasicBlock::instr_iterator I) {
  46   while (I->isBundledWithPred())
  47     --I;
  48   return I;
  49 }
  50
  51 /// Returns an iterator to the first instruction in the bundle containing \p I.
  52 inline MachineBasicBlock::const_instr_iterator getBundleStart(
  53     MachineBasicBlock::const_instr_iterator I) {
  54   while (I->isBundledWithPred())
  55     --I;
  56   return I;
  57 }
  58
  59 /// Returns an iterator pointing beyond the bundle containing \p I.
  60 inline MachineBasicBlock::instr_iterator getBundleEnd(
  61     MachineBasicBlock::instr_iterator I) {
  62   while (I->isBundledWithSucc())
  63     ++I;
  64   return ++I;
  65 }
  66
  67 /// Returns an iterator pointing beyond the bundle containing \p I.
  68 inline MachineBasicBlock::const_instr_iterator getBundleEnd(
  69     MachineBasicBlock::const_instr_iterator I) {
  70   while (I->isBundledWithSucc())
  71     ++I;
  72   return ++I;
  73 }
  74
  75 //===----------------------------------------------------------------------===//
  76 // MachineOperand iterator
  77 //
  78
  79 /// MachineOperandIteratorBase - Iterator that can visit all operands on a
  80 /// MachineInstr, or all operands on a bundle of MachineInstrs.  This class is
  81 /// not intended to be used directly, use one of the sub-classes instead.
  82 ///
  83 /// Intended use:
  84 ///
  85 ///   for (MIBundleOperands MIO(MI); MIO.isValid(); ++MIO) {
  86 ///     if (!MIO->isReg())
  87 ///       continue;
  88 ///     ...
  89 ///   }
  90 ///
  91 class MachineOperandIteratorBase {
  92   MachineBasicBlock::instr_iterator InstrI, InstrE;
  93   MachineInstr::mop_iterator OpI, OpE;
  94
  95   // If the operands on InstrI are exhausted, advance InstrI to the next
  96   // bundled instruction with operands.
  97   void advance() {
  98     while (OpI == OpE) {
  99       // Don't advance off the basic block, or into a new bundle.
 100       if (++InstrI == InstrE || !InstrI->isInsideBundle())
 101         break;
 102       OpI = InstrI->operands_begin();
 103       OpE = InstrI->operands_end();
 104     }
 105   }
 106
 107 protected:
 108   /// MachineOperandIteratorBase - Create an iterator that visits all operands
 109   /// on MI, or all operands on every instruction in the bundle containing MI.
 110   ///
 111   /// @param MI The instruction to examine.
 112   /// @param WholeBundle When true, visit all operands on the entire bundle.
 113   ///
 114   explicit MachineOperandIteratorBase(MachineInstr &MI, bool WholeBundle) {
 115     if (WholeBundle) {
 116       InstrI = getBundleStart(MI.getIterator());
 117       InstrE = MI.getParent()->instr_end();
 118     } else {
 119       InstrI = InstrE = MI.getIterator();
 120       ++InstrE;
 121     }
 122     OpI = InstrI->operands_begin();
 123     OpE = InstrI->operands_end();
 124     if (WholeBundle)
 125       advance();
 126   }
 127
 128   MachineOperand &deref() const { return *OpI; }
 129
 130 public:
 131   /// isValid - Returns true until all the operands have been visited.
 132   bool isValid() const { return OpI != OpE; }
 133
 134   /// Preincrement.  Move to the next operand.
 135   void operator++() {
 136     assert(isValid() && "Cannot advance MIOperands beyond the last operand");
 137     ++OpI;
 138     advance();
 139   }
 140
 141   /// getOperandNo - Returns the number of the current operand relative to its
 142   /// instruction.
 143   ///
 144   unsigned getOperandNo() const {
 145     return OpI - InstrI->operands_begin();
 146   }
 147
 148   /// VirtRegInfo - Information about a virtual register used by a set of operands.
 149   ///
 150   struct VirtRegInfo {
 151     /// Reads - One of the operands read the virtual register.  This does not
 152     /// include undef or internal use operands, see MO::readsReg().
 153     bool Reads;
 154
 155     /// Writes - One of the operands writes the virtual register.
 156     bool Writes;
 157
 158     /// Tied - Uses and defs must use the same register. This can be because of
 159     /// a two-address constraint, or there may be a partial redefinition of a
 160     /// sub-register.
 161     bool Tied;
 162   };
 163
 164   /// Information about how a physical register Reg is used by a set of
 165   /// operands.
 166   struct PhysRegInfo {
 167     /// There is a regmask operand indicating Reg is clobbered.
 168     /// \see MachineOperand::CreateRegMask().
 169     bool Clobbered;
 170
 171     /// Reg or one of its aliases is defined. The definition may only cover
 172     /// parts of the register.
 173     bool Defined;
 174     /// Reg or a super-register is defined. The definition covers the full
 175     /// register.
 176     bool FullyDefined;
 177
 178     /// Reg or one of its aliases is read. The register may only be read
 179     /// partially.
 180     bool Read;
 181     /// Reg or a super-register is read. The full register is read.
 182     bool FullyRead;
 183
 184     /// Either:
 185     /// - Reg is FullyDefined and all defs of reg or an overlapping
 186     ///   register are dead, or
 187     /// - Reg is completely dead because "defined" by a clobber.
 188     bool DeadDef;
 189
 190     /// Reg is Defined and all defs of reg or an overlapping register are
 191     /// dead.
 192     bool PartialDeadDef;
 193
 194     /// There is a use operand of reg or a super-register with kill flag set.
 195     bool Killed;
 196   };
 197
 198   /// analyzeVirtReg - Analyze how the current instruction or bundle uses a
 199   /// virtual register.  This function should not be called after operator++(),
 200   /// it expects a fresh iterator.
 201   ///
 202   /// @param Reg The virtual register to analyze.
 203   /// @param Ops When set, this vector will receive an (MI, OpNum) entry for
 204   ///            each operand referring to Reg.
 205   /// @returns A filled-in RegInfo struct.
 206   VirtRegInfo analyzeVirtReg(unsigned Reg,
 207            SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops = nullptr);
 208
 209   /// analyzePhysReg - Analyze how the current instruction or bundle uses a
 210   /// physical register.  This function should not be called after operator++(),
 211   /// it expects a fresh iterator.
 212   ///
 213   /// @param Reg The physical register to analyze.
 214   /// @returns A filled-in PhysRegInfo struct.
 215   PhysRegInfo analyzePhysReg(unsigned Reg, const TargetRegisterInfo *TRI);
 216 };
 217
 218 /// MIOperands - Iterate over operands of a single instruction.
 219 ///
 220 class MIOperands : public MachineOperandIteratorBase {
 221 public:
 222   MIOperands(MachineInstr &MI) : MachineOperandIteratorBase(MI, false) {}
 223   MachineOperand &operator* () const { return deref(); }
 224   MachineOperand *operator->() const { return &deref(); }
 225 };
 226
 227 /// ConstMIOperands - Iterate over operands of a single const instruction.
 228 ///
 229 class ConstMIOperands : public MachineOperandIteratorBase {
 230 public:
 231   ConstMIOperands(const MachineInstr &MI)
 232       : MachineOperandIteratorBase(const_cast<MachineInstr &>(MI), false) {}
 233   const MachineOperand &operator* () const { return deref(); }
 234   const MachineOperand *operator->() const { return &deref(); }
 235 };
 236
 237 /// MIBundleOperands - Iterate over all operands in a bundle of machine
 238 /// instructions.
 239 ///
 240 class MIBundleOperands : public MachineOperandIteratorBase {
 241 public:
 242   MIBundleOperands(MachineInstr &MI) : MachineOperandIteratorBase(MI, true) {}
 243   MachineOperand &operator* () const { return deref(); }
 244   MachineOperand *operator->() const { return &deref(); }
 245 };
 246
 247 /// ConstMIBundleOperands - Iterate over all operands in a const bundle of
 248 /// machine instructions.
 249 ///
 250 class ConstMIBundleOperands : public MachineOperandIteratorBase {
 251 public:
 252   ConstMIBundleOperands(const MachineInstr &MI)
 253       : MachineOperandIteratorBase(const_cast<MachineInstr &>(MI), true) {}
 254   const MachineOperand &operator* () const { return deref(); }
 255   const MachineOperand *operator->() const { return &deref(); }
 256 };
 257
 258 } // End llvm namespace
 259
 260 #endif