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>
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 
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 
75 void MipsInstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
76   OS << '$' << StringRef(getRegisterName(RegNo)).lower();
77 }
78 
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 
125 static void printExpr(const MCExpr *Expr, const MCAsmInfo *MAI,
126                       raw_ostream &OS) {
127   int Offset = 0;
128   const MCSymbolRefExpr *SRE;
129 
130   if (const MCBinaryExpr *BE = dyn_cast<MCBinaryExpr>(Expr)) {
131     SRE = dyn_cast<MCSymbolRefExpr>(BE->getLHS());
132     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(BE->getRHS());
133     assert(SRE && CE && "Binary expression must be sym+const.");
134     Offset = CE->getValue();
135   } else if (const MipsMCExpr *ME = dyn_cast<MipsMCExpr>(Expr)) {
136     ME->print(OS, MAI);
137     return;
138   } else
139     SRE = cast<MCSymbolRefExpr>(Expr);
140 
141   MCSymbolRefExpr::VariantKind Kind = SRE->getKind();
142 
143   switch (Kind) {
144   default:                                 llvm_unreachable("Invalid kind!");
145   case MCSymbolRefExpr::VK_None:           break;
146   case MCSymbolRefExpr::VK_Mips_GPREL:     OS << "%gp_rel("; break;
147   case MCSymbolRefExpr::VK_Mips_GOT_CALL:  OS << "%call16("; break;
148   case MCSymbolRefExpr::VK_Mips_GOT16:     OS << "%got(";    break;
149   case MCSymbolRefExpr::VK_Mips_GOT:       OS << "%got(";    break;
150   case MCSymbolRefExpr::VK_Mips_ABS_HI:    OS << "%hi(";     break;
151   case MCSymbolRefExpr::VK_Mips_ABS_LO:    OS << "%lo(";     break;
152   case MCSymbolRefExpr::VK_Mips_TLSGD:     OS << "%tlsgd(";  break;
153   case MCSymbolRefExpr::VK_Mips_TLSLDM:    OS << "%tlsldm(";  break;
154   case MCSymbolRefExpr::VK_Mips_DTPREL_HI: OS << "%dtprel_hi(";  break;
155   case MCSymbolRefExpr::VK_Mips_DTPREL_LO: OS << "%dtprel_lo(";  break;
156   case MCSymbolRefExpr::VK_Mips_GOTTPREL:  OS << "%gottprel("; break;
157   case MCSymbolRefExpr::VK_Mips_TPREL_HI:  OS << "%tprel_hi("; break;
158   case MCSymbolRefExpr::VK_Mips_TPREL_LO:  OS << "%tprel_lo("; break;
159   case MCSymbolRefExpr::VK_Mips_GPOFF_HI:  OS << "%hi(%neg(%gp_rel("; break;
160   case MCSymbolRefExpr::VK_Mips_GPOFF_LO:  OS << "%lo(%neg(%gp_rel("; break;
161   case MCSymbolRefExpr::VK_Mips_GOT_DISP:  OS << "%got_disp("; break;
162   case MCSymbolRefExpr::VK_Mips_GOT_PAGE:  OS << "%got_page("; break;
163   case MCSymbolRefExpr::VK_Mips_GOT_OFST:  OS << "%got_ofst("; break;
164   case MCSymbolRefExpr::VK_Mips_HIGHER:    OS << "%higher("; break;
165   case MCSymbolRefExpr::VK_Mips_HIGHEST:   OS << "%highest("; break;
166   case MCSymbolRefExpr::VK_Mips_GOT_HI16:  OS << "%got_hi("; break;
167   case MCSymbolRefExpr::VK_Mips_GOT_LO16:  OS << "%got_lo("; break;
168   case MCSymbolRefExpr::VK_Mips_CALL_HI16: OS << "%call_hi("; break;
169   case MCSymbolRefExpr::VK_Mips_CALL_LO16: OS << "%call_lo("; break;
170   case MCSymbolRefExpr::VK_Mips_PCREL_HI16: OS << "%pcrel_hi("; break;
171   case MCSymbolRefExpr::VK_Mips_PCREL_LO16: OS << "%pcrel_lo("; break;
172   }
173 
174   SRE->getSymbol().print(OS, MAI);
175 
176   if (Offset) {
177     if (Offset > 0)
178       OS << '+';
179     OS << Offset;
180   }
181 
182   if ((Kind == MCSymbolRefExpr::VK_Mips_GPOFF_HI) ||
183       (Kind == MCSymbolRefExpr::VK_Mips_GPOFF_LO))
184     OS << ")))";
185   else if (Kind != MCSymbolRefExpr::VK_None)
186     OS << ')';
187 }
188 
189 void MipsInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
190                                    raw_ostream &O) {
191   const MCOperand &Op = MI->getOperand(OpNo);
192   if (Op.isReg()) {
193     printRegName(O, Op.getReg());
194     return;
195   }
196 
197   if (Op.isImm()) {
198     O << Op.getImm();
199     return;
200   }
201 
202   assert(Op.isExpr() && "unknown operand kind in printOperand");
203   printExpr(Op.getExpr(), &MAI, O);
204 }
205 
206 void MipsInstPrinter::printUnsignedImm(const MCInst *MI, int opNum,
207                                        raw_ostream &O) {
208   const MCOperand &MO = MI->getOperand(opNum);
209   if (MO.isImm())
210     O << (unsigned short int)MO.getImm();
211   else
212     printOperand(MI, opNum, O);
213 }
214 
215 void MipsInstPrinter::printUnsignedImm8(const MCInst *MI, int opNum,
216                                         raw_ostream &O) {
217   const MCOperand &MO = MI->getOperand(opNum);
218   if (MO.isImm())
219     O << (unsigned short int)(unsigned char)MO.getImm();
220   else
221     printOperand(MI, opNum, O);
222 }
223 
224 void MipsInstPrinter::
225 printMemOperand(const MCInst *MI, int opNum, raw_ostream &O) {
226   // Load/Store memory operands -- imm($reg)
227   // If PIC target the target is loaded as the
228   // pattern lw $25,%call16($28)
229 
230   // opNum can be invalid if instruction had reglist as operand.
231   // MemOperand is always last operand of instruction (base + offset).
232   switch (MI->getOpcode()) {
233   default:
234     break;
235   case Mips::SWM32_MM:
236   case Mips::LWM32_MM:
237   case Mips::SWM16_MM:
238   case Mips::LWM16_MM:
239     opNum = MI->getNumOperands() - 2;
240     break;
241   }
242 
243   printOperand(MI, opNum+1, O);
244   O << "(";
245   printOperand(MI, opNum, O);
246   O << ")";
247 }
248 
249 void MipsInstPrinter::
250 printMemOperandEA(const MCInst *MI, int opNum, raw_ostream &O) {
251   // when using stack locations for not load/store instructions
252   // print the same way as all normal 3 operand instructions.
253   printOperand(MI, opNum, O);
254   O << ", ";
255   printOperand(MI, opNum+1, O);
256   return;
257 }
258 
259 void MipsInstPrinter::
260 printFCCOperand(const MCInst *MI, int opNum, raw_ostream &O) {
261   const MCOperand& MO = MI->getOperand(opNum);
262   O << MipsFCCToString((Mips::CondCode)MO.getImm());
263 }
264 
265 void MipsInstPrinter::
266 printRegisterPair(const MCInst *MI, int opNum, raw_ostream &O) {
267   printRegName(O, MI->getOperand(opNum).getReg());
268 }
269 
270 void MipsInstPrinter::
271 printSHFMask(const MCInst *MI, int opNum, raw_ostream &O) {
272   llvm_unreachable("TODO");
273 }
274 
275 bool MipsInstPrinter::printAlias(const char *Str, const MCInst &MI,
276                                  unsigned OpNo, raw_ostream &OS) {
277   OS << "\t" << Str << "\t";
278   printOperand(&MI, OpNo, OS);
279   return true;
280 }
281 
282 bool MipsInstPrinter::printAlias(const char *Str, const MCInst &MI,
283                                  unsigned OpNo0, unsigned OpNo1,
284                                  raw_ostream &OS) {
285   printAlias(Str, MI, OpNo0, OS);
286   OS << ", ";
287   printOperand(&MI, OpNo1, OS);
288   return true;
289 }
290 
291 bool MipsInstPrinter::printAlias(const MCInst &MI, raw_ostream &OS) {
292   switch (MI.getOpcode()) {
293   case Mips::BEQ:
294   case Mips::BEQ_MM:
295     // beq $zero, $zero, $L2 => b $L2
296     // beq $r0, $zero, $L2 => beqz $r0, $L2
297     return (isReg<Mips::ZERO>(MI, 0) && isReg<Mips::ZERO>(MI, 1) &&
298             printAlias("b", MI, 2, OS)) ||
299            (isReg<Mips::ZERO>(MI, 1) && printAlias("beqz", MI, 0, 2, OS));
300   case Mips::BEQ64:
301     // beq $r0, $zero, $L2 => beqz $r0, $L2
302     return isReg<Mips::ZERO_64>(MI, 1) && printAlias("beqz", MI, 0, 2, OS);
303   case Mips::BNE:
304     // bne $r0, $zero, $L2 => bnez $r0, $L2
305     return isReg<Mips::ZERO>(MI, 1) && printAlias("bnez", MI, 0, 2, OS);
306   case Mips::BNE64:
307     // bne $r0, $zero, $L2 => bnez $r0, $L2
308     return isReg<Mips::ZERO_64>(MI, 1) && printAlias("bnez", MI, 0, 2, OS);
309   case Mips::BGEZAL:
310     // bgezal $zero, $L1 => bal $L1
311     return isReg<Mips::ZERO>(MI, 0) && printAlias("bal", MI, 1, OS);
312   case Mips::BC1T:
313     // bc1t $fcc0, $L1 => bc1t $L1
314     return isReg<Mips::FCC0>(MI, 0) && printAlias("bc1t", MI, 1, OS);
315   case Mips::BC1F:
316     // bc1f $fcc0, $L1 => bc1f $L1
317     return isReg<Mips::FCC0>(MI, 0) && printAlias("bc1f", MI, 1, OS);
318   case Mips::JALR:
319     // jalr $ra, $r1 => jalr $r1
320     return isReg<Mips::RA>(MI, 0) && printAlias("jalr", MI, 1, OS);
321   case Mips::JALR64:
322     // jalr $ra, $r1 => jalr $r1
323     return isReg<Mips::RA_64>(MI, 0) && printAlias("jalr", MI, 1, OS);
324   case Mips::NOR:
325   case Mips::NOR_MM:
326     // nor $r0, $r1, $zero => not $r0, $r1
327     return isReg<Mips::ZERO>(MI, 2) && printAlias("not", MI, 0, 1, OS);
328   case Mips::NOR64:
329     // nor $r0, $r1, $zero => not $r0, $r1
330     return isReg<Mips::ZERO_64>(MI, 2) && printAlias("not", MI, 0, 1, OS);
331   case Mips::OR:
332     // or $r0, $r1, $zero => move $r0, $r1
333     return isReg<Mips::ZERO>(MI, 2) && printAlias("move", MI, 0, 1, OS);
334   default: return false;
335   }
336 }
337 
338 void MipsInstPrinter::printSaveRestore(const MCInst *MI, raw_ostream &O) {
339   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
340     if (i != 0) O << ", ";
341     if (MI->getOperand(i).isReg())
342       printRegName(O, MI->getOperand(i).getReg());
343     else
344       printUnsignedImm(MI, i, O);
345   }
346 }
347 
348 void MipsInstPrinter::
349 printRegisterList(const MCInst *MI, int opNum, raw_ostream &O) {
350   // - 2 because register List is always first operand of instruction and it is
351   // always followed by memory operand (base + offset).
352   for (int i = opNum, e = MI->getNumOperands() - 2; i != e; ++i) {
353     if (i != opNum)
354       O << ", ";
355     printRegName(O, MI->getOperand(i).getReg());
356   }
357 }
358