LLVM  12.0.0git
BPFInstPrinter.cpp
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1 //===-- BPFInstPrinter.cpp - Convert BPF MCInst to asm syntax -------------===//
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 class prints an BPF MCInst to a .s file.
10 //
11 //===----------------------------------------------------------------------===//
12 
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCInst.h"
17 #include "llvm/MC/MCSymbol.h"
20 using namespace llvm;
21 
22 #define DEBUG_TYPE "asm-printer"
23 
24 // Include the auto-generated portion of the assembly writer.
25 #include "BPFGenAsmWriter.inc"
26 
27 void BPFInstPrinter::printInst(const MCInst *MI, uint64_t Address,
28  StringRef Annot, const MCSubtargetInfo &STI,
29  raw_ostream &O) {
30  printInstruction(MI, Address, O);
31  printAnnotation(O, Annot);
32 }
33 
34 static void printExpr(const MCExpr *Expr, raw_ostream &O) {
35 #ifndef NDEBUG
36  const MCSymbolRefExpr *SRE;
37 
38  if (const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr))
39  SRE = dyn_cast<MCSymbolRefExpr>(BE->getLHS());
40  else
41  SRE = dyn_cast<MCSymbolRefExpr>(Expr);
42  assert(SRE && "Unexpected MCExpr type.");
43 
44  MCSymbolRefExpr::VariantKind Kind = SRE->getKind();
45 
47 #endif
48  O << *Expr;
49 }
50 
51 void BPFInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
52  raw_ostream &O, const char *Modifier) {
53  assert((Modifier == 0 || Modifier[0] == 0) && "No modifiers supported");
54  const MCOperand &Op = MI->getOperand(OpNo);
55  if (Op.isReg()) {
56  O << getRegisterName(Op.getReg());
57  } else if (Op.isImm()) {
58  O << formatImm((int32_t)Op.getImm());
59  } else {
60  assert(Op.isExpr() && "Expected an expression");
61  printExpr(Op.getExpr(), O);
62  }
63 }
64 
66  const char *Modifier) {
67  const MCOperand &RegOp = MI->getOperand(OpNo);
68  const MCOperand &OffsetOp = MI->getOperand(OpNo + 1);
69 
70  // register
71  assert(RegOp.isReg() && "Register operand not a register");
72  O << getRegisterName(RegOp.getReg());
73 
74  // offset
75  if (OffsetOp.isImm()) {
76  auto Imm = OffsetOp.getImm();
77  if (Imm >= 0)
78  O << " + " << formatImm(Imm);
79  else
80  O << " - " << formatImm(-Imm);
81  } else {
82  assert(0 && "Expected an immediate");
83  }
84 }
85 
86 void BPFInstPrinter::printImm64Operand(const MCInst *MI, unsigned OpNo,
87  raw_ostream &O) {
88  const MCOperand &Op = MI->getOperand(OpNo);
89  if (Op.isImm())
90  O << formatImm(Op.getImm());
91  else if (Op.isExpr())
92  printExpr(Op.getExpr(), O);
93  else
94  O << Op;
95 }
96 
97 void BPFInstPrinter::printBrTargetOperand(const MCInst *MI, unsigned OpNo,
98  raw_ostream &O) {
99  const MCOperand &Op = MI->getOperand(OpNo);
100  if (Op.isImm()) {
101  int16_t Imm = Op.getImm();
102  O << ((Imm >= 0) ? "+" : "") << formatImm(Imm);
103  } else if (Op.isExpr()) {
104  printExpr(Op.getExpr(), O);
105  } else {
106  O << Op;
107  }
108 }
bool isImm() const
Definition: MCInst.h:58
LLVM_NODISCARD std::enable_if_t< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type > dyn_cast(const Y &Val)
Definition: Casting.h:334
This class represents lattice values for constants.
Definition: AllocatorList.h:23
bool isReg() const
Definition: MCInst.h:57
void printImm64Operand(const MCInst *MI, unsigned OpNo, raw_ostream &O)
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:192
unsigned getReg() const
Returns the register number.
Definition: MCInst.h:64
void printOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O, const char *Modifier=nullptr)
format_object< int64_t > formatImm(int64_t Value) const
Utility function to print immediates in decimal or hex.
const MCExpr * getExpr() const
Definition: MCInst.h:95
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:158
int64_t getImm() const
Definition: MCInst.h:75
void printMemOperand(const MCInst *MI, int OpNo, raw_ostream &O, const char *Modifier=nullptr)
bool isExpr() const
Definition: MCInst.h:60
Binary assembler expressions.
Definition: MCExpr.h:481
const MCOperand & getOperand(unsigned i) const
Definition: MCInst.h:180
void printInst(const MCInst *MI, uint64_t Address, StringRef Annot, const MCSubtargetInfo &STI, raw_ostream &O) override
Print the specified MCInst to the specified raw_ostream.
void printInstruction(const MCInst *MI, uint64_t Address, raw_ostream &O)
static void printExpr(const MCExpr *Expr, raw_ostream &O)
static const char * getRegisterName(unsigned RegNo)
Generic base class for all target subtargets.
void printBrTargetOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
void printAnnotation(raw_ostream &OS, StringRef Annot)
Utility function for printing annotations.
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:46
IRTranslator LLVM IR MI
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
Instances of this class represent operands of the MCInst class.
Definition: MCInst.h:34