1 //===----------------------- MIRNamer.cpp - MIR Namer ---------------------===//
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 // The purpose of this pass is to rename virtual register operands with the goal
10 // of making it easier to author easier to read tests for MIR. This pass reuses
11 // the vreg renamer used by MIRCanonicalizerPass.
12 //
13 // Basic Usage:
14 //
15 // llc -o - -run-pass mir-namer example.mir
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #include "MIRVRegNamerUtils.h"
20 #include "llvm/ADT/PostOrderIterator.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/CodeGen/MachineFunctionPass.h"
23 #include "llvm/CodeGen/MachineInstrBuilder.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/Passes.h"
26 #include "llvm/InitializePasses.h"
27 
28 using namespace llvm;
29 
30 namespace llvm {
31 extern char &MIRNamerID;
32 } // namespace llvm
33 
34 #define DEBUG_TYPE "mir-namer"
35 
36 namespace {
37 
38 class MIRNamer : public MachineFunctionPass {
39 public:
40   static char ID;
41   MIRNamer() : MachineFunctionPass(ID) {}
42 
43   StringRef getPassName() const override {
44     return "Rename virtual register operands";
45   }
46 
47   void getAnalysisUsage(AnalysisUsage &AU) const override {
48     AU.setPreservesCFG();
49     MachineFunctionPass::getAnalysisUsage(AU);
50   }
51 
52   bool runOnMachineFunction(MachineFunction &MF) override {
53     bool Changed = false;
54 
55     if (MF.empty())
56       return Changed;
57 
58     VRegRenamer Renamer(MF.getRegInfo());
59 
60     unsigned BBIndex = 0;
61     ReversePostOrderTraversal<MachineBasicBlock *> RPOT(&*MF.begin());
62     for (auto &MBB : RPOT)
63       Changed |= Renamer.renameVRegs(MBB, BBIndex++);
64 
65     return Changed;
66   }
67 };
68 
69 } // end anonymous namespace
70 
71 char MIRNamer::ID;
72 
73 char &llvm::MIRNamerID = MIRNamer::ID;
74 
75 INITIALIZE_PASS_BEGIN(MIRNamer, "mir-namer", "Rename Register Operands", false,
76                       false)
77 
78 INITIALIZE_PASS_END(MIRNamer, "mir-namer", "Rename Register Operands", false,
79                     false)
80