1 //===-- MipsInstPrinter.cpp - Convert Mips MCInst to assembly syntax ------===//
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 class prints an Mips MCInst to a .s file.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MipsInstPrinter.h"
15 #include "MCTargetDesc/MipsMCExpr.h"
16 #include "MipsInstrInfo.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/MC/MCExpr.h"
19 #include "llvm/MC/MCInst.h"
20 #include "llvm/MC/MCInstrInfo.h"
21 #include "llvm/MC/MCSymbol.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 using namespace llvm;
25 
26 #define DEBUG_TYPE "asm-printer"
27 
28 #define PRINT_ALIAS_INSTR
29 #include "MipsGenAsmWriter.inc"
30 
31 template<unsigned R>
isReg(const MCInst & MI,unsigned OpNo)32 static bool isReg(const MCInst &MI, unsigned OpNo) {
33   assert(MI.getOperand(OpNo).isReg() && "Register operand expected.");
34   return MI.getOperand(OpNo).getReg() == R;
35 }
36 
MipsFCCToString(Mips::CondCode CC)37 const char* Mips::MipsFCCToString(Mips::CondCode CC) {
38   switch (CC) {
39   case FCOND_F:
40   case FCOND_T:   return "f";
41   case FCOND_UN:
42   case FCOND_OR:  return "un";
43   case FCOND_OEQ:
44   case FCOND_UNE: return "eq";
45   case FCOND_UEQ:
46   case FCOND_ONE: return "ueq";
47   case FCOND_OLT:
48   case FCOND_UGE: return "olt";
49   case FCOND_ULT:
50   case FCOND_OGE: return "ult";
51   case FCOND_OLE:
52   case FCOND_UGT: return "ole";
53   case FCOND_ULE:
54   case FCOND_OGT: return "ule";
55   case FCOND_SF:
56   case FCOND_ST:  return "sf";
57   case FCOND_NGLE:
58   case FCOND_GLE: return "ngle";
59   case FCOND_SEQ:
60   case FCOND_SNE: return "seq";
61   case FCOND_NGL:
62   case FCOND_GL:  return "ngl";
63   case FCOND_LT:
64   case FCOND_NLT: return "lt";
65   case FCOND_NGE:
66   case FCOND_GE:  return "nge";
67   case FCOND_LE:
68   case FCOND_NLE: return "le";
69   case FCOND_NGT:
70   case FCOND_GT:  return "ngt";
71   }
72   llvm_unreachable("Impossible condition code!");
73 }
74 
printRegName(raw_ostream & OS,unsigned RegNo) const75 void MipsInstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
76   OS << '$' << StringRef(getRegisterName(RegNo)).lower();
77 }
78 
printInst(const MCInst * MI,raw_ostream & O,StringRef Annot,const MCSubtargetInfo & STI)79 void MipsInstPrinter::printInst(const MCInst *MI, raw_ostream &O,
80                                 StringRef Annot, const MCSubtargetInfo &STI) {
81   switch (MI->getOpcode()) {
82   default:
83     break;
84   case Mips::RDHWR:
85   case Mips::RDHWR64:
86     O << "\t.set\tpush\n";
87     O << "\t.set\tmips32r2\n";
88     break;
89   case Mips::Save16:
90     O << "\tsave\t";
91     printSaveRestore(MI, O);
92     O << " # 16 bit inst\n";
93     return;
94   case Mips::SaveX16:
95     O << "\tsave\t";
96     printSaveRestore(MI, O);
97     O << "\n";
98     return;
99   case Mips::Restore16:
100     O << "\trestore\t";
101     printSaveRestore(MI, O);
102     O << " # 16 bit inst\n";
103     return;
104   case Mips::RestoreX16:
105     O << "\trestore\t";
106     printSaveRestore(MI, O);
107     O << "\n";
108     return;
109   }
110 
111   // Try to print any aliases first.
112   if (!printAliasInstr(MI, O) && !printAlias(*MI, O))
113     printInstruction(MI, O);
114   printAnnotation(O, Annot);
115 
116   switch (MI->getOpcode()) {
117   default:
118     break;
119   case Mips::RDHWR:
120   case Mips::RDHWR64:
121     O << "\n\t.set\tpop";
122   }
123 }
124 
printExpr(const MCExpr * Expr,raw_ostream & OS)125 static void printExpr(const MCExpr *Expr, raw_ostream &OS) {
126   int Offset = 0;
127   const MCSymbolRefExpr *SRE;
128 
129   if (const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr)) {
130     SRE = dyn_cast<MCSymbolRefExpr>(BE->getLHS());
131     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(BE->getRHS());
132     assert(SRE && CE && "Binary expression must be sym+const.");
133     Offset = CE->getValue();
134   } else if (const MipsMCExpr *ME = dyn_cast<MipsMCExpr>(Expr)) {
135     ME->print(OS);
136     return;
137   } else
138     SRE = cast<MCSymbolRefExpr>(Expr);
139 
140   MCSymbolRefExpr::VariantKind Kind = SRE->getKind();
141 
142   switch (Kind) {
143   default:                                 llvm_unreachable("Invalid kind!");
144   case MCSymbolRefExpr::VK_None:           break;
145   case MCSymbolRefExpr::VK_Mips_GPREL:     OS << "%gp_rel("; break;
146   case MCSymbolRefExpr::VK_Mips_GOT_CALL:  OS << "%call16("; break;
147   case MCSymbolRefExpr::VK_Mips_GOT16:     OS << "%got(";    break;
148   case MCSymbolRefExpr::VK_Mips_GOT:       OS << "%got(";    break;
149   case MCSymbolRefExpr::VK_Mips_ABS_HI:    OS << "%hi(";     break;
150   case MCSymbolRefExpr::VK_Mips_ABS_LO:    OS << "%lo(";     break;
151   case MCSymbolRefExpr::VK_Mips_TLSGD:     OS << "%tlsgd(";  break;
152   case MCSymbolRefExpr::VK_Mips_TLSLDM:    OS << "%tlsldm(";  break;
153   case MCSymbolRefExpr::VK_Mips_DTPREL_HI: OS << "%dtprel_hi(";  break;
154   case MCSymbolRefExpr::VK_Mips_DTPREL_LO: OS << "%dtprel_lo(";  break;
155   case MCSymbolRefExpr::VK_Mips_GOTTPREL:  OS << "%gottprel("; break;
156   case MCSymbolRefExpr::VK_Mips_TPREL_HI:  OS << "%tprel_hi("; break;
157   case MCSymbolRefExpr::VK_Mips_TPREL_LO:  OS << "%tprel_lo("; break;
158   case MCSymbolRefExpr::VK_Mips_GPOFF_HI:  OS << "%hi(%neg(%gp_rel("; break;
159   case MCSymbolRefExpr::VK_Mips_GPOFF_LO:  OS << "%lo(%neg(%gp_rel("; break;
160   case MCSymbolRefExpr::VK_Mips_GOT_DISP:  OS << "%got_disp("; break;
161   case MCSymbolRefExpr::VK_Mips_GOT_PAGE:  OS << "%got_page("; break;
162   case MCSymbolRefExpr::VK_Mips_GOT_OFST:  OS << "%got_ofst("; break;
163   case MCSymbolRefExpr::VK_Mips_HIGHER:    OS << "%higher("; break;
164   case MCSymbolRefExpr::VK_Mips_HIGHEST:   OS << "%highest("; break;
165   case MCSymbolRefExpr::VK_Mips_GOT_HI16:  OS << "%got_hi("; break;
166   case MCSymbolRefExpr::VK_Mips_GOT_LO16:  OS << "%got_lo("; break;
167   case MCSymbolRefExpr::VK_Mips_CALL_HI16: OS << "%call_hi("; break;
168   case MCSymbolRefExpr::VK_Mips_CALL_LO16: OS << "%call_lo("; break;
169   case MCSymbolRefExpr::VK_Mips_PCREL_HI16: OS << "%pcrel_hi("; break;
170   case MCSymbolRefExpr::VK_Mips_PCREL_LO16: OS << "%pcrel_lo("; break;
171   }
172 
173   OS << SRE->getSymbol();
174 
175   if (Offset) {
176     if (Offset > 0)
177       OS << '+';
178     OS << Offset;
179   }
180 
181   if ((Kind == MCSymbolRefExpr::VK_Mips_GPOFF_HI) ||
182       (Kind == MCSymbolRefExpr::VK_Mips_GPOFF_LO))
183     OS << ")))";
184   else if (Kind != MCSymbolRefExpr::VK_None)
185     OS << ')';
186 }
187 
printOperand(const MCInst * MI,unsigned OpNo,raw_ostream & O)188 void MipsInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
189                                    raw_ostream &O) {
190   const MCOperand &Op = MI->getOperand(OpNo);
191   if (Op.isReg()) {
192     printRegName(O, Op.getReg());
193     return;
194   }
195 
196   if (Op.isImm()) {
197     O << Op.getImm();
198     return;
199   }
200 
201   assert(Op.isExpr() && "unknown operand kind in printOperand");
202   printExpr(Op.getExpr(), O);
203 }
204 
printUnsignedImm(const MCInst * MI,int opNum,raw_ostream & O)205 void MipsInstPrinter::printUnsignedImm(const MCInst *MI, int opNum,
206                                        raw_ostream &O) {
207   const MCOperand &MO = MI->getOperand(opNum);
208   if (MO.isImm())
209     O << (unsigned short int)MO.getImm();
210   else
211     printOperand(MI, opNum, O);
212 }
213 
printUnsignedImm8(const MCInst * MI,int opNum,raw_ostream & O)214 void MipsInstPrinter::printUnsignedImm8(const MCInst *MI, int opNum,
215                                         raw_ostream &O) {
216   const MCOperand &MO = MI->getOperand(opNum);
217   if (MO.isImm())
218     O << (unsigned short int)(unsigned char)MO.getImm();
219   else
220     printOperand(MI, opNum, O);
221 }
222 
223 void MipsInstPrinter::
printMemOperand(const MCInst * MI,int opNum,raw_ostream & O)224 printMemOperand(const MCInst *MI, int opNum, raw_ostream &O) {
225   // Load/Store memory operands -- imm($reg)
226   // If PIC target the target is loaded as the
227   // pattern lw $25,%call16($28)
228 
229   // opNum can be invalid if instruction had reglist as operand.
230   // MemOperand is always last operand of instruction (base + offset).
231   switch (MI->getOpcode()) {
232   default:
233     break;
234   case Mips::SWM32_MM:
235   case Mips::LWM32_MM:
236   case Mips::SWM16_MM:
237   case Mips::LWM16_MM:
238     opNum = MI->getNumOperands() - 2;
239     break;
240   }
241 
242   printOperand(MI, opNum+1, O);
243   O << "(";
244   printOperand(MI, opNum, O);
245   O << ")";
246 }
247 
248 void MipsInstPrinter::
printMemOperandEA(const MCInst * MI,int opNum,raw_ostream & O)249 printMemOperandEA(const MCInst *MI, int opNum, raw_ostream &O) {
250   // when using stack locations for not load/store instructions
251   // print the same way as all normal 3 operand instructions.
252   printOperand(MI, opNum, O);
253   O << ", ";
254   printOperand(MI, opNum+1, O);
255   return;
256 }
257 
258 void MipsInstPrinter::
printFCCOperand(const MCInst * MI,int opNum,raw_ostream & O)259 printFCCOperand(const MCInst *MI, int opNum, raw_ostream &O) {
260   const MCOperand& MO = MI->getOperand(opNum);
261   O << MipsFCCToString((Mips::CondCode)MO.getImm());
262 }
263 
264 void MipsInstPrinter::
printRegisterPair(const MCInst * MI,int opNum,raw_ostream & O)265 printRegisterPair(const MCInst *MI, int opNum, raw_ostream &O) {
266   printRegName(O, MI->getOperand(opNum).getReg());
267 }
268 
269 void MipsInstPrinter::
printSHFMask(const MCInst * MI,int opNum,raw_ostream & O)270 printSHFMask(const MCInst *MI, int opNum, raw_ostream &O) {
271   llvm_unreachable("TODO");
272 }
273 
printAlias(const char * Str,const MCInst & MI,unsigned OpNo,raw_ostream & OS)274 bool MipsInstPrinter::printAlias(const char *Str, const MCInst &MI,
275                                  unsigned OpNo, raw_ostream &OS) {
276   OS << "\t" << Str << "\t";
277   printOperand(&MI, OpNo, OS);
278   return true;
279 }
280 
printAlias(const char * Str,const MCInst & MI,unsigned OpNo0,unsigned OpNo1,raw_ostream & OS)281 bool MipsInstPrinter::printAlias(const char *Str, const MCInst &MI,
282                                  unsigned OpNo0, unsigned OpNo1,
283                                  raw_ostream &OS) {
284   printAlias(Str, MI, OpNo0, OS);
285   OS << ", ";
286   printOperand(&MI, OpNo1, OS);
287   return true;
288 }
289 
printAlias(const MCInst & MI,raw_ostream & OS)290 bool MipsInstPrinter::printAlias(const MCInst &MI, raw_ostream &OS) {
291   switch (MI.getOpcode()) {
292   case Mips::BEQ:
293   case Mips::BEQ_MM:
294     // beq $zero, $zero, $L2 => b $L2
295     // beq $r0, $zero, $L2 => beqz $r0, $L2
296     return (isReg<Mips::ZERO>(MI, 0) && isReg<Mips::ZERO>(MI, 1) &&
297             printAlias("b", MI, 2, OS)) ||
298            (isReg<Mips::ZERO>(MI, 1) && printAlias("beqz", MI, 0, 2, OS));
299   case Mips::BEQ64:
300     // beq $r0, $zero, $L2 => beqz $r0, $L2
301     return isReg<Mips::ZERO_64>(MI, 1) && printAlias("beqz", MI, 0, 2, OS);
302   case Mips::BNE:
303     // bne $r0, $zero, $L2 => bnez $r0, $L2
304     return isReg<Mips::ZERO>(MI, 1) && printAlias("bnez", MI, 0, 2, OS);
305   case Mips::BNE64:
306     // bne $r0, $zero, $L2 => bnez $r0, $L2
307     return isReg<Mips::ZERO_64>(MI, 1) && printAlias("bnez", MI, 0, 2, OS);
308   case Mips::BGEZAL:
309     // bgezal $zero, $L1 => bal $L1
310     return isReg<Mips::ZERO>(MI, 0) && printAlias("bal", MI, 1, OS);
311   case Mips::BC1T:
312     // bc1t $fcc0, $L1 => bc1t $L1
313     return isReg<Mips::FCC0>(MI, 0) && printAlias("bc1t", MI, 1, OS);
314   case Mips::BC1F:
315     // bc1f $fcc0, $L1 => bc1f $L1
316     return isReg<Mips::FCC0>(MI, 0) && printAlias("bc1f", MI, 1, OS);
317   case Mips::JALR:
318     // jalr $ra, $r1 => jalr $r1
319     return isReg<Mips::RA>(MI, 0) && printAlias("jalr", MI, 1, OS);
320   case Mips::JALR64:
321     // jalr $ra, $r1 => jalr $r1
322     return isReg<Mips::RA_64>(MI, 0) && printAlias("jalr", MI, 1, OS);
323   case Mips::NOR:
324   case Mips::NOR_MM:
325     // nor $r0, $r1, $zero => not $r0, $r1
326     return isReg<Mips::ZERO>(MI, 2) && printAlias("not", MI, 0, 1, OS);
327   case Mips::NOR64:
328     // nor $r0, $r1, $zero => not $r0, $r1
329     return isReg<Mips::ZERO_64>(MI, 2) && printAlias("not", MI, 0, 1, OS);
330   case Mips::OR:
331     // or $r0, $r1, $zero => move $r0, $r1
332     return isReg<Mips::ZERO>(MI, 2) && printAlias("move", MI, 0, 1, OS);
333   default: return false;
334   }
335 }
336 
printSaveRestore(const MCInst * MI,raw_ostream & O)337 void MipsInstPrinter::printSaveRestore(const MCInst *MI, raw_ostream &O) {
338   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
339     if (i != 0) O << ", ";
340     if (MI->getOperand(i).isReg())
341       printRegName(O, MI->getOperand(i).getReg());
342     else
343       printUnsignedImm(MI, i, O);
344   }
345 }
346 
347 void MipsInstPrinter::
printRegisterList(const MCInst * MI,int opNum,raw_ostream & O)348 printRegisterList(const MCInst *MI, int opNum, raw_ostream &O) {
349   // - 2 because register List is always first operand of instruction and it is
350   // always followed by memory operand (base + offset).
351   for (int i = opNum, e = MI->getNumOperands() - 2; i != e; ++i) {
352     if (i != opNum)
353       O << ", ";
354     printRegName(O, MI->getOperand(i).getReg());
355   }
356 }
357