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1 //===-- HexagonAsmPrinter.cpp - Print machine instrs to Hexagon assembly --===//
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 file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to Hexagon assembly language. This printer is
12 // the output mechanism used by `llc'.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 
17 #define DEBUG_TYPE "asm-printer"
18 #include "Hexagon.h"
19 #include "HexagonAsmPrinter.h"
20 #include "HexagonMachineFunctionInfo.h"
21 #include "HexagonTargetMachine.h"
22 #include "HexagonSubtarget.h"
23 #include "InstPrinter/HexagonInstPrinter.h"
24 #include "llvm/Constants.h"
25 #include "llvm/DerivedTypes.h"
26 #include "llvm/Module.h"
27 #include "llvm/Analysis/ConstantFolding.h"
28 #include "llvm/Assembly/Writer.h"
29 #include "llvm/CodeGen/AsmPrinter.h"
30 #include "llvm/CodeGen/MachineModuleInfo.h"
31 #include "llvm/CodeGen/MachineFunctionPass.h"
32 #include "llvm/CodeGen/MachineInstr.h"
33 #include "llvm/CodeGen/MachineInstrBuilder.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCContext.h"
36 #include "llvm/MC/MCExpr.h"
37 #include "llvm/MC/MCInst.h"
38 #include "llvm/MC/MCSection.h"
39 #include "llvm/MC/MCStreamer.h"
40 #include "llvm/MC/MCSymbol.h"
41 #include "llvm/Support/MathExtras.h"
42 #include "llvm/Support/CommandLine.h"
43 #include "llvm/Support/Debug.h"
44 #include "llvm/Support/Compiler.h"
45 #include "llvm/Support/Format.h"
46 #include "llvm/Support/raw_ostream.h"
47 #include "llvm/Support/TargetRegistry.h"
48 #include "llvm/Target/Mangler.h"
49 #include "llvm/Target/TargetData.h"
50 #include "llvm/Target/TargetLoweringObjectFile.h"
51 #include "llvm/Target/TargetRegisterInfo.h"
52 #include "llvm/Target/TargetInstrInfo.h"
53 #include "llvm/Target/TargetOptions.h"
54 #include "llvm/ADT/SmallString.h"
55 #include "llvm/ADT/SmallVector.h"
56 #include "llvm/ADT/StringExtras.h"
57 
58 using namespace llvm;
59 
60 static cl::opt<bool> AlignCalls(
61          "hexagon-align-calls", cl::Hidden, cl::init(true),
62           cl::desc("Insert falign after call instruction for Hexagon target"));
63 
EmitAlignment(unsigned NumBits,const GlobalValue * GV) const64 void HexagonAsmPrinter::EmitAlignment(unsigned NumBits,
65                                       const GlobalValue *GV) const {
66   // For basic block level alignment, use ".falign".
67   if (!GV) {
68     OutStreamer.EmitRawText(StringRef("\t.falign"));
69     return;
70   }
71 
72   AsmPrinter::EmitAlignment(NumBits, GV);
73 }
74 
printOperand(const MachineInstr * MI,unsigned OpNo,raw_ostream & O)75 void HexagonAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
76                                     raw_ostream &O) {
77   const MachineOperand &MO = MI->getOperand(OpNo);
78 
79   switch (MO.getType()) {
80   default:
81     assert(0 && "<unknown operand type>");
82   case MachineOperand::MO_Register:
83     O << HexagonInstPrinter::getRegisterName(MO.getReg());
84     return;
85   case MachineOperand::MO_Immediate:
86     O << MO.getImm();
87     return;
88   case MachineOperand::MO_MachineBasicBlock:
89     O << *MO.getMBB()->getSymbol();
90     return;
91   case MachineOperand::MO_JumpTableIndex:
92     O << *GetJTISymbol(MO.getIndex());
93     // FIXME: PIC relocation model.
94     return;
95   case MachineOperand::MO_ConstantPoolIndex:
96     O << *GetCPISymbol(MO.getIndex());
97     return;
98   case MachineOperand::MO_ExternalSymbol:
99     O << *GetExternalSymbolSymbol(MO.getSymbolName());
100     return;
101   case MachineOperand::MO_GlobalAddress:
102     // Computing the address of a global symbol, not calling it.
103     O << *Mang->getSymbol(MO.getGlobal());
104     printOffset(MO.getOffset(), O);
105     return;
106   }
107 }
108 
109 //
110 // isBlockOnlyReachableByFallthrough - We need to override this since the
111 // default AsmPrinter does not print labels for any basic block that
112 // is only reachable by a fall through. That works for all cases except
113 // for the case in which the basic block is reachable by a fall through but
114 // through an indirect from a jump table. In this case, the jump table
115 // will contain a label not defined by AsmPrinter.
116 //
117 bool HexagonAsmPrinter::
isBlockOnlyReachableByFallthrough(const MachineBasicBlock * MBB) const118 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
119   if (MBB->hasAddressTaken()) {
120     return false;
121   }
122   return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB);
123 }
124 
125 
126 /// PrintAsmOperand - Print out an operand for an inline asm expression.
127 ///
PrintAsmOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & OS)128 bool HexagonAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
129                                         unsigned AsmVariant,
130                                         const char *ExtraCode,
131                                         raw_ostream &OS) {
132   // Does this asm operand have a single letter operand modifier?
133   if (ExtraCode && ExtraCode[0]) {
134     if (ExtraCode[1] != 0) return true; // Unknown modifier.
135 
136     switch (ExtraCode[0]) {
137     default: return true;  // Unknown modifier.
138     case 'c': // Don't print "$" before a global var name or constant.
139       // Hexagon never has a prefix.
140       printOperand(MI, OpNo, OS);
141       return false;
142     case 'L': // Write second word of DImode reference.
143       // Verify that this operand has two consecutive registers.
144       if (!MI->getOperand(OpNo).isReg() ||
145           OpNo+1 == MI->getNumOperands() ||
146           !MI->getOperand(OpNo+1).isReg())
147         return true;
148       ++OpNo;   // Return the high-part.
149       break;
150     case 'I':
151       // Write 'i' if an integer constant, otherwise nothing.  Used to print
152       // addi vs add, etc.
153       if (MI->getOperand(OpNo).isImm())
154         OS << "i";
155       return false;
156     }
157   }
158 
159   printOperand(MI, OpNo, OS);
160   return false;
161 }
162 
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)163 bool HexagonAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
164                                             unsigned OpNo, unsigned AsmVariant,
165                                             const char *ExtraCode,
166                                             raw_ostream &O) {
167   if (ExtraCode && ExtraCode[0])
168     return true; // Unknown modifier.
169 
170   const MachineOperand &Base  = MI->getOperand(OpNo);
171   const MachineOperand &Offset = MI->getOperand(OpNo+1);
172 
173   if (Base.isReg())
174     printOperand(MI, OpNo, O);
175   else
176     llvm_unreachable("Unimplemented");
177 
178   if (Offset.isImm()) {
179     if (Offset.getImm())
180       O << " + #" << Offset.getImm();
181   }
182   else
183     llvm_unreachable("Unimplemented");
184 
185   return false;
186 }
187 
printPredicateOperand(const MachineInstr * MI,unsigned OpNo,raw_ostream & O)188 void HexagonAsmPrinter::printPredicateOperand(const MachineInstr *MI,
189                                               unsigned OpNo,
190                                               raw_ostream &O) {
191   llvm_unreachable("Unimplemented");
192 }
193 
194 
195 /// printMachineInstruction -- Print out a single Hexagon MI in Darwin syntax to
196 /// the current output stream.
197 ///
EmitInstruction(const MachineInstr * MI)198 void HexagonAsmPrinter::EmitInstruction(const MachineInstr *MI) {
199   MCInst MCI;
200 
201   HexagonLowerToMC(MI, MCI, *this);
202   OutStreamer.EmitInstruction(MCI);
203 
204   return;
205 }
206 
207 /// PrintUnmangledNameSafely - Print out the printable characters in the name.
208 /// Don't print things like \n or \0.
209 // static void PrintUnmangledNameSafely(const Value *V, raw_ostream &OS) {
210 //   for (const char *Name = V->getNameStart(), *E = Name+V->getNameLen();
211 //        Name != E; ++Name)
212 //     if (isprint(*Name))
213 //       OS << *Name;
214 // }
215 
216 
printAddrModeBasePlusOffset(const MachineInstr * MI,int OpNo,raw_ostream & O)217 void HexagonAsmPrinter::printAddrModeBasePlusOffset(const MachineInstr *MI,
218                                                     int OpNo, raw_ostream &O) {
219   const MachineOperand &MO1 = MI->getOperand(OpNo);
220   const MachineOperand &MO2 = MI->getOperand(OpNo+1);
221 
222   O << HexagonInstPrinter::getRegisterName(MO1.getReg())
223     << " + #"
224     << MO2.getImm();
225 }
226 
227 
printGlobalOperand(const MachineInstr * MI,int OpNo,raw_ostream & O)228 void HexagonAsmPrinter::printGlobalOperand(const MachineInstr *MI, int OpNo,
229                                            raw_ostream &O) {
230   const MachineOperand &MO = MI->getOperand(OpNo);
231   assert( (MO.getType() == MachineOperand::MO_GlobalAddress) &&
232          "Expecting global address");
233 
234   O << *Mang->getSymbol(MO.getGlobal());
235   if (MO.getOffset() != 0) {
236     O << " + ";
237     O << MO.getOffset();
238   }
239 }
240 
printJumpTable(const MachineInstr * MI,int OpNo,raw_ostream & O)241 void HexagonAsmPrinter::printJumpTable(const MachineInstr *MI, int OpNo,
242                                        raw_ostream &O) {
243   const MachineOperand &MO = MI->getOperand(OpNo);
244   assert( (MO.getType() == MachineOperand::MO_JumpTableIndex) &&
245 	  "Expecting jump table index");
246 
247   // Hexagon_TODO: Do we need name mangling?
248   O << *GetJTISymbol(MO.getIndex());
249 }
250 
printConstantPool(const MachineInstr * MI,int OpNo,raw_ostream & O)251 void HexagonAsmPrinter::printConstantPool(const MachineInstr *MI, int OpNo,
252                                           raw_ostream &O) {
253   const MachineOperand &MO = MI->getOperand(OpNo);
254   assert( (MO.getType() == MachineOperand::MO_ConstantPoolIndex) &&
255           "Expecting constant pool index");
256 
257   // Hexagon_TODO: Do we need name mangling?
258   O << *GetCPISymbol(MO.getIndex());
259 }
260 
createHexagonMCInstPrinter(const Target & T,unsigned SyntaxVariant,const MCAsmInfo & MAI,const MCInstrInfo & MII,const MCRegisterInfo & MRI,const MCSubtargetInfo & STI)261 static MCInstPrinter *createHexagonMCInstPrinter(const Target &T,
262                                                  unsigned SyntaxVariant,
263                                                  const MCAsmInfo &MAI,
264                                                  const MCInstrInfo &MII,
265                                                  const MCRegisterInfo &MRI,
266                                                  const MCSubtargetInfo &STI) {
267   if (SyntaxVariant == 0)
268     return(new HexagonInstPrinter(MAI, MII, MRI));
269   else
270    return NULL;
271 }
272 
LLVMInitializeHexagonAsmPrinter()273 extern "C" void LLVMInitializeHexagonAsmPrinter() {
274   RegisterAsmPrinter<HexagonAsmPrinter> X(TheHexagonTarget);
275 
276   TargetRegistry::RegisterMCInstPrinter(TheHexagonTarget,
277                                         createHexagonMCInstPrinter);
278 }
279