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 #define DEBUG_TYPE "asm-printer"
17 #include "Hexagon.h"
18 #include "HexagonAsmPrinter.h"
19 #include "HexagonMachineFunctionInfo.h"
20 #include "HexagonSubtarget.h"
21 #include "HexagonTargetMachine.h"
22 #include "InstPrinter/HexagonInstPrinter.h"
23 #include "MCTargetDesc/HexagonMCInst.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringExtras.h"
27 #include "llvm/Analysis/ConstantFolding.h"
28 #include "llvm/CodeGen/AsmPrinter.h"
29 #include "llvm/CodeGen/MachineFunctionPass.h"
30 #include "llvm/CodeGen/MachineInstr.h"
31 #include "llvm/CodeGen/MachineInstrBuilder.h"
32 #include "llvm/CodeGen/MachineModuleInfo.h"
33 #include "llvm/IR/Constants.h"
34 #include "llvm/IR/DataLayout.h"
35 #include "llvm/IR/DerivedTypes.h"
36 #include "llvm/IR/Mangler.h"
37 #include "llvm/IR/Module.h"
38 #include "llvm/MC/MCAsmInfo.h"
39 #include "llvm/MC/MCContext.h"
40 #include "llvm/MC/MCExpr.h"
41 #include "llvm/MC/MCInst.h"
42 #include "llvm/MC/MCSection.h"
43 #include "llvm/MC/MCStreamer.h"
44 #include "llvm/MC/MCSymbol.h"
45 #include "llvm/Support/CommandLine.h"
46 #include "llvm/Support/Compiler.h"
47 #include "llvm/Support/Debug.h"
48 #include "llvm/Support/Format.h"
49 #include "llvm/Support/MathExtras.h"
50 #include "llvm/Support/TargetRegistry.h"
51 #include "llvm/Support/raw_ostream.h"
52 #include "llvm/Target/TargetInstrInfo.h"
53 #include "llvm/Target/TargetLoweringObjectFile.h"
54 #include "llvm/Target/TargetOptions.h"
55 #include "llvm/Target/TargetRegisterInfo.h"
56 
57 using namespace llvm;
58 
59 static cl::opt<bool> AlignCalls(
60          "hexagon-align-calls", cl::Hidden, cl::init(true),
61           cl::desc("Insert falign after call instruction for Hexagon target"));
62 
63 void HexagonAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
64                                     raw_ostream &O) {
65   const MachineOperand &MO = MI->getOperand(OpNo);
66 
67   switch (MO.getType()) {
68   default: llvm_unreachable ("<unknown operand type>");
69   case MachineOperand::MO_Register:
70     O << HexagonInstPrinter::getRegisterName(MO.getReg());
71     return;
72   case MachineOperand::MO_Immediate:
73     O << MO.getImm();
74     return;
75   case MachineOperand::MO_MachineBasicBlock:
76     O << *MO.getMBB()->getSymbol();
77     return;
78   case MachineOperand::MO_ConstantPoolIndex:
79     O << *GetCPISymbol(MO.getIndex());
80     return;
81   case MachineOperand::MO_GlobalAddress:
82     // Computing the address of a global symbol, not calling it.
83     O << *getSymbol(MO.getGlobal());
84     printOffset(MO.getOffset(), O);
85     return;
86   }
87 }
88 
89 //
90 // isBlockOnlyReachableByFallthrough - We need to override this since the
91 // default AsmPrinter does not print labels for any basic block that
92 // is only reachable by a fall through. That works for all cases except
93 // for the case in which the basic block is reachable by a fall through but
94 // through an indirect from a jump table. In this case, the jump table
95 // will contain a label not defined by AsmPrinter.
96 //
97 bool HexagonAsmPrinter::
98 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
99   if (MBB->hasAddressTaken()) {
100     return false;
101   }
102   return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB);
103 }
104 
105 
106 /// PrintAsmOperand - Print out an operand for an inline asm expression.
107 ///
108 bool HexagonAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
109                                         unsigned AsmVariant,
110                                         const char *ExtraCode,
111                                         raw_ostream &OS) {
112   // Does this asm operand have a single letter operand modifier?
113   if (ExtraCode && ExtraCode[0]) {
114     if (ExtraCode[1] != 0) return true; // Unknown modifier.
115 
116     switch (ExtraCode[0]) {
117     default:
118       // See if this is a generic print operand
119       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
120     case 'c': // Don't print "$" before a global var name or constant.
121       // Hexagon never has a prefix.
122       printOperand(MI, OpNo, OS);
123       return false;
124     case 'L': // Write second word of DImode reference.
125       // Verify that this operand has two consecutive registers.
126       if (!MI->getOperand(OpNo).isReg() ||
127           OpNo+1 == MI->getNumOperands() ||
128           !MI->getOperand(OpNo+1).isReg())
129         return true;
130       ++OpNo;   // Return the high-part.
131       break;
132     case 'I':
133       // Write 'i' if an integer constant, otherwise nothing.  Used to print
134       // addi vs add, etc.
135       if (MI->getOperand(OpNo).isImm())
136         OS << "i";
137       return false;
138     }
139   }
140 
141   printOperand(MI, OpNo, OS);
142   return false;
143 }
144 
145 bool HexagonAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
146                                             unsigned OpNo, unsigned AsmVariant,
147                                             const char *ExtraCode,
148                                             raw_ostream &O) {
149   if (ExtraCode && ExtraCode[0])
150     return true; // Unknown modifier.
151 
152   const MachineOperand &Base  = MI->getOperand(OpNo);
153   const MachineOperand &Offset = MI->getOperand(OpNo+1);
154 
155   if (Base.isReg())
156     printOperand(MI, OpNo, O);
157   else
158     llvm_unreachable("Unimplemented");
159 
160   if (Offset.isImm()) {
161     if (Offset.getImm())
162       O << " + #" << Offset.getImm();
163   }
164   else
165     llvm_unreachable("Unimplemented");
166 
167   return false;
168 }
169 
170 
171 /// printMachineInstruction -- Print out a single Hexagon MI in Darwin syntax to
172 /// the current output stream.
173 ///
174 void HexagonAsmPrinter::EmitInstruction(const MachineInstr *MI) {
175   if (MI->isBundle()) {
176     std::vector<const MachineInstr*> BundleMIs;
177 
178     const MachineBasicBlock *MBB = MI->getParent();
179     MachineBasicBlock::const_instr_iterator MII = MI;
180     ++MII;
181     unsigned int IgnoreCount = 0;
182     while (MII != MBB->end() && MII->isInsideBundle()) {
183       const MachineInstr *MInst = MII;
184       if (MInst->getOpcode() == TargetOpcode::DBG_VALUE ||
185           MInst->getOpcode() == TargetOpcode::IMPLICIT_DEF) {
186           IgnoreCount++;
187           ++MII;
188           continue;
189       }
190       //BundleMIs.push_back(&*MII);
191       BundleMIs.push_back(MInst);
192       ++MII;
193     }
194     unsigned Size = BundleMIs.size();
195     assert((Size+IgnoreCount) == MI->getBundleSize() && "Corrupt Bundle!");
196     for (unsigned Index = 0; Index < Size; Index++) {
197       HexagonMCInst MCI;
198       MCI.setPacketStart(Index == 0);
199       MCI.setPacketEnd(Index == (Size-1));
200 
201       HexagonLowerToMC(BundleMIs[Index], MCI, *this);
202       EmitToStreamer(OutStreamer, MCI);
203     }
204   }
205   else {
206     HexagonMCInst MCI;
207     if (MI->getOpcode() == Hexagon::ENDLOOP0) {
208       MCI.setPacketStart(true);
209       MCI.setPacketEnd(true);
210     }
211     HexagonLowerToMC(MI, MCI, *this);
212     EmitToStreamer(OutStreamer, MCI);
213   }
214 
215   return;
216 }
217 
218 static MCInstPrinter *createHexagonMCInstPrinter(const Target &T,
219                                                  unsigned SyntaxVariant,
220                                                  const MCAsmInfo &MAI,
221                                                  const MCInstrInfo &MII,
222                                                  const MCRegisterInfo &MRI,
223                                                  const MCSubtargetInfo &STI) {
224   if (SyntaxVariant == 0)
225     return(new HexagonInstPrinter(MAI, MII, MRI));
226   else
227    return NULL;
228 }
229 
230 extern "C" void LLVMInitializeHexagonAsmPrinter() {
231   RegisterAsmPrinter<HexagonAsmPrinter> X(TheHexagonTarget);
232 
233   TargetRegistry::RegisterMCInstPrinter(TheHexagonTarget,
234                                         createHexagonMCInstPrinter);
235 }
236