CodeEmitterGen.cpp revision f745a20deb40ba0113fe368efcba5393e9d3e99c 
1#include "Support/Statistic.h"
2#include "Record.h"
3#include "CodeEmitterGen.h"
4
5bool CodeEmitterGen::run(std::ostream &o) {
6  std::vector<Record*> Insts;
7
8  const std::map<std::string, Record*> &Defs = Records.getDefs();
9  Record *Inst = Records.getClass("Instruction");
10  assert(Inst && "Couldn't find Instruction class!");
11
12  for (std::map<std::string, Record*>::const_iterator I = Defs.begin(),
13	 E = Defs.end(); I != E; ++I)
14    if (I->second->isSubClassOf(Inst))
15      Insts.push_back(I->second);
16
17  std::string Namespace = "V9::";
18  std::string ClassName = "SparcV9CodeEmitter::";
19
20  //const std::string &Namespace = Inst->getValue("Namespace")->getName();
21  o << "unsigned " << ClassName
22    << "getBinaryCodeForInstr(MachineInstr &MI) {\n"
23    << "  unsigned Value = 0;\n"
24    << "  DEBUG(std::cerr << MI);\n"
25    << "  switch (MI.getOpcode()) {\n";
26  for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
27       I != E; ++I)
28  {
29    Record *R = *I;
30    o << "    case " << Namespace << R->getName() << ": {\n"
31      << "      DEBUG(std::cerr << \"Emitting " << R->getName() << "\\n\");\n";
32
33    const RecordVal *InstVal = R->getValue("Inst");
34    if (!InstVal) {
35      std::cerr << "No 'Inst' record found in target description file!\n";
36      return true;
37    }
38
39    Init *InitVal = InstVal->getValue();
40    assert(dynamic_cast<BitsInit*>(InitVal) &&
41           "Can only handle undefined bits<> types!");
42    BitsInit *BI = (BitsInit*)InitVal;
43
44    unsigned Value = 0;
45    const std::vector<RecordVal> &Vals = R->getValues();
46
47    DEBUG(o << "      // prefilling: ");
48    // Start by filling in fixed values...
49    for (unsigned i = 0, e = BI->getNumBits(); i != e; ++i) {
50      if (BitInit *B = dynamic_cast<BitInit*>(BI->getBit(e-i-1))) {
51        Value |= B->getValue() << (e-i-1);
52        DEBUG(o << B->getValue());
53      } else {
54        DEBUG(o << "0");
55      }
56    }
57    DEBUG(o << "\n");
58
59    DEBUG(o << "      // " << *InstVal << "\n");
60    o << "      Value = " << Value << "U;\n\n";
61
62    // Loop over all of the fields in the instruction adding in any
63    // contributions to this value (due to bit references).
64    //
65    unsigned op = 0;
66    std::map<const std::string,unsigned> OpOrder;
67    std::map<const std::string,bool> OpContinuous;
68    for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
69      if (Vals[i].getName() != "Inst" &&
70          !Vals[i].getValue()->isComplete() &&
71          /* ignore annul and predict bits since no one sets them yet */
72          Vals[i].getName() != "annul" &&
73          Vals[i].getName() != "predict")
74      {
75        o << "      // op" << op << ": " << Vals[i].getName() << "\n"
76          << "      int64_t op" << op
77          <<" = getMachineOpValue(MI, MI.getOperand("<<op<<"));\n";
78        //<< "      MachineOperand &op" << op <<" = MI.getOperand("<<op<<");\n";
79        OpOrder[Vals[i].getName()] = op++;
80
81        // Is the operand continuous? If so, we can just mask and OR it in
82        // instead of doing it bit-by-bit, saving a lot in runtime cost.
83        const BitsInit *InstInit = BI;
84        int beginBitInVar = -1, endBitInVar = -1,
85          beginBitInInst = -1, endBitInInst = -1;
86        bool continuous = true;
87
88        for (int bit = InstInit->getNumBits()-1; bit >= 0; --bit) {
89          if (VarBitInit *VBI =
90              dynamic_cast<VarBitInit*>(InstInit->getBit(bit))) {
91            TypedInit *TI = VBI->getVariable();
92            if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
93              // only process the current variable
94              if (VI->getName() != Vals[i].getName())
95                continue;
96
97              if (beginBitInVar == -1)
98                beginBitInVar = VBI->getBitNum();
99
100              if (endBitInVar == -1)
101                endBitInVar = VBI->getBitNum();
102              else {
103                if (endBitInVar == (int)VBI->getBitNum() + 1)
104                  endBitInVar = VBI->getBitNum();
105                else {
106                  continuous = false;
107                  break;
108                }
109              }
110
111              if (beginBitInInst == -1)
112                beginBitInInst = bit;
113              if (endBitInInst == -1)
114                endBitInInst = bit;
115              else {
116                if (endBitInInst == bit + 1)
117                  endBitInInst = bit;
118                else {
119                  continuous = false;
120                  break;
121                }
122              }
123
124              // maintain same distance between bits in field and bits in
125              // instruction. if the relative distances stay the same
126              // throughout,
127              if ((beginBitInVar - (int)VBI->getBitNum()) !=
128                  (beginBitInInst - bit))
129              {
130                continuous = false;
131                break;
132              }
133            }
134          }
135        }
136
137        DEBUG(o << "      // Var: begin = " << beginBitInVar
138                << ", end = " << endBitInVar
139                << "; Inst: begin = " << beginBitInInst
140                << ", end = " << endBitInInst << "\n");
141
142        if (continuous) {
143          DEBUG(o << "      // continuous: op" << OpOrder[Vals[i].getName()]
144                  << "\n");
145
146          // Mask off the right bits
147          // Low mask (ie. shift, if necessary)
148          if (endBitInVar != 0) {
149            o << "      op" << OpOrder[Vals[i].getName()]
150              << " >>= " << endBitInVar << ";\n";
151            beginBitInVar -= endBitInVar;
152            endBitInVar = 0;
153          }
154
155          // High mask
156          o << "      op" << OpOrder[Vals[i].getName()]
157            << " &= (1<<" << beginBitInVar+1 << ") - 1;\n";
158
159          // Shift the value to the correct place (according to place in instr)
160          if (endBitInInst != 0)
161            o << "      op" << OpOrder[Vals[i].getName()]
162              << " <<= " << endBitInInst << ";\n";
163
164          // Just OR in the result
165          o << "      Value |= op" << OpOrder[Vals[i].getName()] << ";\n";
166        }
167
168        // otherwise, will be taken care of in the loop below using this value:
169        OpContinuous[Vals[i].getName()] = continuous;
170      }
171    }
172
173    for (unsigned f = 0, e = Vals.size(); f != e; ++f) {
174      if (Vals[f].getPrefix()) {
175        BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue();
176
177        // Scan through the field looking for bit initializers of the current
178        // variable...
179        for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) {
180          if (BitInit *BI=dynamic_cast<BitInit*>(FieldInitializer->getBit(i)))
181          {
182            DEBUG(o << "      // bit init: f: " << f << ", i: " << i << "\n");
183          } else if (UnsetInit *UI =
184                     dynamic_cast<UnsetInit*>(FieldInitializer->getBit(i))) {
185            DEBUG(o << "      // unset init: f: " << f << ", i: " << i << "\n");
186          } else if (VarBitInit *VBI =
187                     dynamic_cast<VarBitInit*>(FieldInitializer->getBit(i))) {
188            TypedInit *TI = VBI->getVariable();
189            if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
190              // If the bits of the field are laid out consecutively in the
191              // instruction, then instead of separately ORing in bits, just
192              // mask and shift the entire field for efficiency.
193              if (OpContinuous[VI->getName()]) {
194                // already taken care of in the loop above, thus there is no
195                // need to individually OR in the bits
196
197                // for debugging, output the regular version anyway, commented
198                DEBUG(o << "      // Value |= getValueBit(op"
199                        << OpOrder[VI->getName()] << ", " << VBI->getBitNum()
200                        << ")" << " << " << i << ";\n");
201              } else {
202                o << "      Value |= getValueBit(op" << OpOrder[VI->getName()]
203                  << ", " << VBI->getBitNum()
204                  << ")" << " << " << i << ";\n";
205              }
206            } else if (FieldInit *FI = dynamic_cast<FieldInit*>(TI)) {
207              // FIXME: implement this!
208              o << "FIELD INIT not implemented yet!\n";
209            } else {
210              o << "Error: UNIMPLEMENTED\n";
211            }
212          }
213        }
214      } else {
215        // ignore annul and predict bits since no one sets them yet
216        if (Vals[f].getName() == "annul" || Vals[f].getName() == "predict") {
217          o << "      // found " << Vals[f].getName() << "\n";
218        }
219      }
220    }
221
222    o << "      break;\n"
223      << "    }\n";
224  }
225
226  o << "  default:\n"
227    << "    DEBUG(std::cerr << \"Not supported instr: \" << MI << \"\\n\");\n"
228    << "    abort();\n"
229    << "  }\n"
230    << "  return Value;\n"
231    << "}\n";
232  return false;
233}
234