1 //===-- CodeGen/MachineInstBundle.h - MI bundle utilities -------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file provide utility functions to manipulate machine instruction
11 // bundles.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #ifndef LLVM_CODEGEN_MACHINEINSTRBUNDLE_H
16 #define LLVM_CODEGEN_MACHINEINSTRBUNDLE_H
17
18 #include "llvm/CodeGen/MachineBasicBlock.h"
19
20 namespace llvm {
21
22 /// finalizeBundle - Finalize a machine instruction bundle which includes
23 /// a sequence of instructions starting from FirstMI to LastMI (exclusive).
24 /// This routine adds a BUNDLE instruction to represent the bundle, it adds
25 /// IsInternalRead markers to MachineOperands which are defined inside the
26 /// bundle, and it copies externally visible defs and uses to the BUNDLE
27 /// instruction.
28 void finalizeBundle(MachineBasicBlock &MBB,
29 MachineBasicBlock::instr_iterator FirstMI,
30 MachineBasicBlock::instr_iterator LastMI);
31
32 /// finalizeBundle - Same functionality as the previous finalizeBundle except
33 /// the last instruction in the bundle is not provided as an input. This is
34 /// used in cases where bundles are pre-determined by marking instructions
35 /// with 'InsideBundle' marker. It returns the MBB instruction iterator that
36 /// points to the end of the bundle.
37 MachineBasicBlock::instr_iterator finalizeBundle(MachineBasicBlock &MBB,
38 MachineBasicBlock::instr_iterator FirstMI);
39
40 /// finalizeBundles - Finalize instruction bundles in the specified
41 /// MachineFunction. Return true if any bundles are finalized.
42 bool finalizeBundles(MachineFunction &MF);
43
44 /// getBundleStart - Returns the first instruction in the bundle containing MI.
45 ///
getBundleStart(MachineInstr & MI)46 inline MachineInstr &getBundleStart(MachineInstr &MI) {
47 MachineBasicBlock::instr_iterator I(MI);
48 while (I->isBundledWithPred())
49 --I;
50 return *I;
51 }
52
getBundleStart(const MachineInstr & MI)53 inline const MachineInstr &getBundleStart(const MachineInstr &MI) {
54 MachineBasicBlock::const_instr_iterator I(MI);
55 while (I->isBundledWithPred())
56 --I;
57 return *I;
58 }
59
60 /// Return an iterator pointing beyond the bundle containing MI.
getBundleEnd(MachineInstr & MI)61 inline MachineBasicBlock::instr_iterator getBundleEnd(MachineInstr &MI) {
62 MachineBasicBlock::instr_iterator I(MI);
63 while (I->isBundledWithSucc())
64 ++I;
65 return ++I;
66 }
67
68 /// Return an iterator pointing beyond the bundle containing MI.
69 inline MachineBasicBlock::const_instr_iterator
getBundleEnd(const MachineInstr & MI)70 getBundleEnd(const MachineInstr &MI) {
71 MachineBasicBlock::const_instr_iterator I(MI);
72 while (I->isBundledWithSucc())
73 ++I;
74 return ++I;
75 }
76
77 //===----------------------------------------------------------------------===//
78 // MachineOperand iterator
79 //
80
81 /// MachineOperandIteratorBase - Iterator that can visit all operands on a
82 /// MachineInstr, or all operands on a bundle of MachineInstrs. This class is
83 /// not intended to be used directly, use one of the sub-classes instead.
84 ///
85 /// Intended use:
86 ///
87 /// for (MIBundleOperands MIO(MI); MIO.isValid(); ++MIO) {
88 /// if (!MIO->isReg())
89 /// continue;
90 /// ...
91 /// }
92 ///
93 class MachineOperandIteratorBase {
94 MachineBasicBlock::instr_iterator InstrI, InstrE;
95 MachineInstr::mop_iterator OpI, OpE;
96
97 // If the operands on InstrI are exhausted, advance InstrI to the next
98 // bundled instruction with operands.
advance()99 void advance() {
100 while (OpI == OpE) {
101 // Don't advance off the basic block, or into a new bundle.
102 if (++InstrI == InstrE || !InstrI->isInsideBundle())
103 break;
104 OpI = InstrI->operands_begin();
105 OpE = InstrI->operands_end();
106 }
107 }
108
109 protected:
110 /// MachineOperandIteratorBase - Create an iterator that visits all operands
111 /// on MI, or all operands on every instruction in the bundle containing MI.
112 ///
113 /// @param MI The instruction to examine.
114 /// @param WholeBundle When true, visit all operands on the entire bundle.
115 ///
MachineOperandIteratorBase(MachineInstr & MI,bool WholeBundle)116 explicit MachineOperandIteratorBase(MachineInstr &MI, bool WholeBundle) {
117 if (WholeBundle) {
118 InstrI = getBundleStart(MI).getIterator();
119 InstrE = MI.getParent()->instr_end();
120 } else {
121 InstrI = InstrE = MI.getIterator();
122 ++InstrE;
123 }
124 OpI = InstrI->operands_begin();
125 OpE = InstrI->operands_end();
126 if (WholeBundle)
127 advance();
128 }
129
deref()130 MachineOperand &deref() const { return *OpI; }
131
132 public:
133 /// isValid - Returns true until all the operands have been visited.
isValid()134 bool isValid() const { return OpI != OpE; }
135
136 /// Preincrement. Move to the next operand.
137 void operator++() {
138 assert(isValid() && "Cannot advance MIOperands beyond the last operand");
139 ++OpI;
140 advance();
141 }
142
143 /// getOperandNo - Returns the number of the current operand relative to its
144 /// instruction.
145 ///
getOperandNo()146 unsigned getOperandNo() const {
147 return OpI - InstrI->operands_begin();
148 }
149
150 /// VirtRegInfo - Information about a virtual register used by a set of operands.
151 ///
152 struct VirtRegInfo {
153 /// Reads - One of the operands read the virtual register. This does not
154 /// include <undef> or <internal> use operands, see MO::readsReg().
155 bool Reads;
156
157 /// Writes - One of the operands writes the virtual register.
158 bool Writes;
159
160 /// Tied - Uses and defs must use the same register. This can be because of
161 /// a two-address constraint, or there may be a partial redefinition of a
162 /// sub-register.
163 bool Tied;
164 };
165
166 /// Information about how a physical register Reg is used by a set of
167 /// operands.
168 struct PhysRegInfo {
169 /// There is a regmask operand indicating Reg is clobbered.
170 /// \see MachineOperand::CreateRegMask().
171 bool Clobbered;
172
173 /// Reg or one of its aliases is defined. The definition may only cover
174 /// parts of the register.
175 bool Defined;
176 /// Reg or a super-register is defined. The definition covers the full
177 /// register.
178 bool FullyDefined;
179
180 /// Reg or one of its aliases is read. The register may only be read
181 /// partially.
182 bool Read;
183 /// Reg or a super-register is read. The full register is read.
184 bool FullyRead;
185
186 /// Either:
187 /// - Reg is FullyDefined and all defs of reg or an overlapping
188 /// register are dead, or
189 /// - Reg is completely dead because "defined" by a clobber.
190 bool DeadDef;
191
192 /// Reg is Defined and all defs of reg or an overlapping register are
193 /// dead.
194 bool PartialDeadDef;
195
196 /// There is a use operand of reg or a super-register with kill flag set.
197 bool Killed;
198 };
199
200 /// analyzeVirtReg - Analyze how the current instruction or bundle uses a
201 /// virtual register. This function should not be called after operator++(),
202 /// it expects a fresh iterator.
203 ///
204 /// @param Reg The virtual register to analyze.
205 /// @param Ops When set, this vector will receive an (MI, OpNum) entry for
206 /// each operand referring to Reg.
207 /// @returns A filled-in RegInfo struct.
208 VirtRegInfo analyzeVirtReg(unsigned Reg,
209 SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops = nullptr);
210
211 /// analyzePhysReg - Analyze how the current instruction or bundle uses a
212 /// physical register. This function should not be called after operator++(),
213 /// it expects a fresh iterator.
214 ///
215 /// @param Reg The physical register to analyze.
216 /// @returns A filled-in PhysRegInfo struct.
217 PhysRegInfo analyzePhysReg(unsigned Reg, const TargetRegisterInfo *TRI);
218 };
219
220 /// MIOperands - Iterate over operands of a single instruction.
221 ///
222 class MIOperands : public MachineOperandIteratorBase {
223 public:
MIOperands(MachineInstr & MI)224 MIOperands(MachineInstr &MI) : MachineOperandIteratorBase(MI, false) {}
225 MachineOperand &operator* () const { return deref(); }
226 MachineOperand *operator->() const { return &deref(); }
227 };
228
229 /// ConstMIOperands - Iterate over operands of a single const instruction.
230 ///
231 class ConstMIOperands : public MachineOperandIteratorBase {
232 public:
ConstMIOperands(const MachineInstr & MI)233 ConstMIOperands(const MachineInstr &MI)
234 : MachineOperandIteratorBase(const_cast<MachineInstr &>(MI), false) {}
235 const MachineOperand &operator* () const { return deref(); }
236 const MachineOperand *operator->() const { return &deref(); }
237 };
238
239 /// MIBundleOperands - Iterate over all operands in a bundle of machine
240 /// instructions.
241 ///
242 class MIBundleOperands : public MachineOperandIteratorBase {
243 public:
MIBundleOperands(MachineInstr & MI)244 MIBundleOperands(MachineInstr &MI) : MachineOperandIteratorBase(MI, true) {}
245 MachineOperand &operator* () const { return deref(); }
246 MachineOperand *operator->() const { return &deref(); }
247 };
248
249 /// ConstMIBundleOperands - Iterate over all operands in a const bundle of
250 /// machine instructions.
251 ///
252 class ConstMIBundleOperands : public MachineOperandIteratorBase {
253 public:
ConstMIBundleOperands(const MachineInstr & MI)254 ConstMIBundleOperands(const MachineInstr &MI)
255 : MachineOperandIteratorBase(const_cast<MachineInstr &>(MI), true) {}
256 const MachineOperand &operator* () const { return deref(); }
257 const MachineOperand *operator->() const { return &deref(); }
258 };
259
260 } // End llvm namespace
261
262 #endif
263