1 //===-- RISCVInstPrinter.cpp - Convert RISCV 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 RISCV MCInst to a .s file.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "RISCVInstPrinter.h"
14 #include "MCTargetDesc/RISCVMCExpr.h"
15 #include "Utils/RISCVBaseInfo.h"
16 #include "llvm/MC/MCAsmInfo.h"
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCInst.h"
19 #include "llvm/MC/MCRegisterInfo.h"
20 #include "llvm/MC/MCSubtargetInfo.h"
21 #include "llvm/MC/MCSymbol.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/FormattedStream.h"
25 using namespace llvm;
26 
27 #define DEBUG_TYPE "asm-printer"
28 
29 // Include the auto-generated portion of the assembly writer.
30 #define PRINT_ALIAS_INSTR
31 #include "RISCVGenAsmWriter.inc"
32 
33 // Include the auto-generated portion of the compress emitter.
34 #define GEN_UNCOMPRESS_INSTR
35 #include "RISCVGenCompressInstEmitter.inc"
36 
37 static cl::opt<bool>
38     NoAliases("riscv-no-aliases",
39               cl::desc("Disable the emission of assembler pseudo instructions"),
40               cl::init(false), cl::Hidden);
41 
42 static cl::opt<bool>
43     ArchRegNames("riscv-arch-reg-names",
44                  cl::desc("Print architectural register names rather than the "
45                           "ABI names (such as x2 instead of sp)"),
46                  cl::init(false), cl::Hidden);
47 
48 // The command-line flags above are used by llvm-mc and llc. They can be used by
49 // `llvm-objdump`, but we override their values here to handle options passed to
50 // `llvm-objdump` with `-M` (which matches GNU objdump). There did not seem to
51 // be an easier way to allow these options in all these tools, without doing it
52 // this way.
53 bool RISCVInstPrinter::applyTargetSpecificCLOption(StringRef Opt) {
54   if (Opt == "no-aliases") {
55     NoAliases = true;
56     return true;
57   }
58   if (Opt == "numeric") {
59     ArchRegNames = true;
60     return true;
61   }
62 
63   return false;
64 }
65 
66 void RISCVInstPrinter::printInst(const MCInst *MI, uint64_t Address,
67                                  StringRef Annot, const MCSubtargetInfo &STI,
68                                  raw_ostream &O) {
69   bool Res = false;
70   const MCInst *NewMI = MI;
71   MCInst UncompressedMI;
72   if (!NoAliases)
73     Res = uncompressInst(UncompressedMI, *MI, MRI, STI);
74   if (Res)
75     NewMI = const_cast<MCInst *>(&UncompressedMI);
76   if (NoAliases || !printAliasInstr(NewMI, STI, O))
77     printInstruction(NewMI, Address, STI, O);
78   printAnnotation(O, Annot);
79 }
80 
81 void RISCVInstPrinter::printRegName(raw_ostream &O, unsigned RegNo) const {
82   O << getRegisterName(RegNo);
83 }
84 
85 void RISCVInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
86                                     const MCSubtargetInfo &STI, raw_ostream &O,
87                                     const char *Modifier) {
88   assert((Modifier == 0 || Modifier[0] == 0) && "No modifiers supported");
89   const MCOperand &MO = MI->getOperand(OpNo);
90 
91   if (MO.isReg()) {
92     printRegName(O, MO.getReg());
93     return;
94   }
95 
96   if (MO.isImm()) {
97     O << MO.getImm();
98     return;
99   }
100 
101   assert(MO.isExpr() && "Unknown operand kind in printOperand");
102   MO.getExpr()->print(O, &MAI);
103 }
104 
105 void RISCVInstPrinter::printCSRSystemRegister(const MCInst *MI, unsigned OpNo,
106                                               const MCSubtargetInfo &STI,
107                                               raw_ostream &O) {
108   unsigned Imm = MI->getOperand(OpNo).getImm();
109   auto SysReg = RISCVSysReg::lookupSysRegByEncoding(Imm);
110   if (SysReg && SysReg->haveRequiredFeatures(STI.getFeatureBits()))
111     O << SysReg->Name;
112   else
113     O << Imm;
114 }
115 
116 void RISCVInstPrinter::printFenceArg(const MCInst *MI, unsigned OpNo,
117                                      const MCSubtargetInfo &STI,
118                                      raw_ostream &O) {
119   unsigned FenceArg = MI->getOperand(OpNo).getImm();
120   assert (((FenceArg >> 4) == 0) && "Invalid immediate in printFenceArg");
121 
122   if ((FenceArg & RISCVFenceField::I) != 0)
123     O << 'i';
124   if ((FenceArg & RISCVFenceField::O) != 0)
125     O << 'o';
126   if ((FenceArg & RISCVFenceField::R) != 0)
127     O << 'r';
128   if ((FenceArg & RISCVFenceField::W) != 0)
129     O << 'w';
130   if (FenceArg == 0)
131     O << "unknown";
132 }
133 
134 void RISCVInstPrinter::printFRMArg(const MCInst *MI, unsigned OpNo,
135                                    const MCSubtargetInfo &STI, raw_ostream &O) {
136   auto FRMArg =
137       static_cast<RISCVFPRndMode::RoundingMode>(MI->getOperand(OpNo).getImm());
138   O << RISCVFPRndMode::roundingModeToString(FRMArg);
139 }
140 
141 void RISCVInstPrinter::printAtomicMemOp(const MCInst *MI, unsigned OpNo,
142                                         const MCSubtargetInfo &STI,
143                                         raw_ostream &O) {
144   const MCOperand &MO = MI->getOperand(OpNo);
145 
146   assert(MO.isReg() && "printAtomicMemOp can only print register operands");
147   O << "(";
148   printRegName(O, MO.getReg());
149   O << ")";
150   return;
151 }
152 
153 const char *RISCVInstPrinter::getRegisterName(unsigned RegNo) {
154   return getRegisterName(RegNo, ArchRegNames ? RISCV::NoRegAltName
155                                              : RISCV::ABIRegAltName);
156 }
157