CodeEmitterGen.cpp revision 7eac4766b156ad2965125a7ee3f1f4834dfbb00b 
1#include "Record.h"
2#include "CodeEmitterGen.h"
3
4void CodeEmitterGen::createEmitter(std::ostream &o) {
5  std::vector<Record*> Insts;
6
7  const std::map<std::string, Record*> &Defs = Records.getDefs();
8  Record *Inst = Records.getClass("Instruction");
9  assert(Inst && "Couldn't find Instruction class!");
10
11  for (std::map<std::string, Record*>::const_iterator I = Defs.begin(),
12	 E = Defs.end(); I != E; ++I)
13    if (I->second->isSubClassOf(Inst))
14      Insts.push_back(I->second);
15
16  std::string Namespace = "V9::";
17  std::string ClassName = "SparcV9CodeEmitter::";
18
19  //const std::string &Namespace = Inst->getValue("Namespace")->getName();
20  o << "unsigned " << ClassName
21    << "getBinaryCodeForInstr(MachineInstr &MI) {\n"
22    << "  unsigned Value = 0;\n"
23    << "  DEBUG(std::cerr << MI);\n"
24    << "  switch (MI.getOpcode()) {\n";
25  for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
26       I != E; ++I)
27  {
28    Record *R = *I;
29    o << "    case " << Namespace << R->getName() << ": {\n"
30      << "      DEBUG(std::cerr << \"Emitting " << R->getName() << "\\n\");\n";
31
32    const RecordVal *InstVal = R->getValue("Inst");
33    Init *InitVal = InstVal->getValue();
34
35    assert(dynamic_cast<BitsInit*>(InitVal) &&
36           "Can only handle undefined bits<> types!");
37    BitsInit *BI = (BitsInit*)InitVal;
38
39    unsigned Value = 0;
40    const std::vector<RecordVal> &Vals = R->getValues();
41
42    o << "      // prefilling: ";
43    // Start by filling in fixed values...
44    for (unsigned i = 0, e = BI->getNumBits(); i != e; ++i) {
45      if (BitInit *B = dynamic_cast<BitInit*>(BI->getBit(e-i-1))) {
46        Value |= B->getValue() << (e-i-1);
47        o << B->getValue();
48      } else {
49        o << "0";
50      }
51    }
52    o << "\n";
53
54    o << "      // " << *InstVal << "\n";
55    o << "      Value = " << Value << "U;\n\n";
56
57    // Loop over all of the fields in the instruction adding in any
58    // contributions to this value (due to bit references).
59    //
60    unsigned op = 0;
61    std::map<const std::string,unsigned> OpOrder;
62    std::map<const std::string,bool> OpContinuous;
63    for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
64      if (Vals[i].getName() != "Inst" &&
65          !Vals[i].getValue()->isComplete() &&
66          /* ignore annul and predict bits since no one sets them yet */
67          Vals[i].getName() != "annul" &&
68          Vals[i].getName() != "predict")
69      {
70        o << "      // op" << op << ": " << Vals[i].getName() << "\n"
71          << "      int64_t op" << op
72          <<" = getMachineOpValue(MI, MI.getOperand("<<op<<"));\n";
73        //<< "      MachineOperand &op" << op <<" = MI.getOperand("<<op<<");\n";
74        OpOrder[Vals[i].getName()] = op++;
75
76        // Is the operand continuous? If so, we can just mask and OR it in
77        // instead of doing it bit-by-bit, saving a lot in runtime cost.
78        const BitsInit *InstInit = BI;
79        int beginBitInVar = -1, endBitInVar = -1,
80          beginBitInInst = -1, endBitInInst = -1;
81        bool continuous = true;
82
83        for (int bit = InstInit->getNumBits()-1; bit >= 0; --bit) {
84          if (VarBitInit *VBI =
85              dynamic_cast<VarBitInit*>(InstInit->getBit(bit))) {
86            TypedInit *TI = VBI->getVariable();
87            if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
88              // only process the current variable
89              if (VI->getName() != Vals[i].getName())
90                continue;
91
92              if (beginBitInVar == -1)
93                beginBitInVar = VBI->getBitNum();
94
95              if (endBitInVar == -1)
96                endBitInVar = VBI->getBitNum();
97              else {
98                if (endBitInVar == (int)VBI->getBitNum() + 1)
99                  endBitInVar = VBI->getBitNum();
100                else {
101                  continuous = false;
102                  break;
103                }
104              }
105
106              if (beginBitInInst == -1)
107                beginBitInInst = bit;
108              if (endBitInInst == -1)
109                endBitInInst = bit;
110              else {
111                if (endBitInInst == bit + 1)
112                  endBitInInst = bit;
113                else {
114                  continuous = false;
115                  break;
116                }
117              }
118
119              // maintain same distance between bits in field and bits in
120              // instruction. if the relative distances stay the same
121              // throughout,
122              if ((beginBitInVar - (int)VBI->getBitNum()) !=
123                  (beginBitInInst - bit))
124              {
125                continuous = false;
126                break;
127              }
128            }
129          }
130        }
131
132        if (continuous) {
133          o << "      // continuous: op" << OpOrder[Vals[i].getName()] << "\n";
134
135          // Mask off the right bits
136          // Low mask (ie. shift, if necessary)
137          if (endBitInVar != 0) {
138            o << "      op" << OpOrder[Vals[i].getName()]
139              << " >>= endBitInVar;\n";
140            beginBitInVar -= endBitInVar;
141            endBitInVar = 0;
142          }
143
144          // High mask
145          o << "      op" << OpOrder[Vals[i].getName()]
146            << " &= (1<<" << beginBitInVar+1 << ") - 1;\n";
147
148          // Shift the value to the correct place (according to place in instr)
149          if (endBitInInst != 0)
150            o << "      op" << OpOrder[Vals[i].getName()]
151              << " <<= " << endBitInInst << ";\n";
152
153          // Just OR in the result
154          o << "      Value |= op" << OpOrder[Vals[i].getName()] << ";\n";
155        }
156
157        // otherwise, will be taken care of in the loop below using this value:
158        OpContinuous[Vals[i].getName()] = continuous;
159      }
160    }
161
162    for (unsigned f = 0, e = Vals.size(); f != e; ++f) {
163      if (Vals[f].getPrefix()) {
164        BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue();
165
166        // Scan through the field looking for bit initializers of the current
167        // variable...
168        for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) {
169          if (BitInit *BI=dynamic_cast<BitInit*>(FieldInitializer->getBit(i)))
170          {
171            o << "      // bit init: f: " << f << ", i: " << i << "\n";
172          } else if (UnsetInit *UI =
173                     dynamic_cast<UnsetInit*>(FieldInitializer->getBit(i))) {
174            o << "      // unset init: f: " << f << ", i: " << i << "\n";
175          } else if (VarBitInit *VBI =
176                     dynamic_cast<VarBitInit*>(FieldInitializer->getBit(i))) {
177            TypedInit *TI = VBI->getVariable();
178            if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
179              // If the bits of the field are laid out consecutively in the
180              // instruction, then instead of separately ORing in bits, just
181              // mask and shift the entire field for efficiency.
182              if (OpContinuous[VI->getName()]) {
183                // already taken care of in the loop above, thus there is no
184                // need to individually OR in the bits
185
186                // for debugging, output the regular version anyway, commented
187                o << "      // Value |= getValueBit(op"
188                  << OpOrder[VI->getName()] << ", " << VBI->getBitNum()
189                  << ")" << " << " << i << ";\n";
190              } else {
191                o << "      Value |= getValueBit(op" << OpOrder[VI->getName()]
192                  << ", " << VBI->getBitNum()
193                  << ")" << " << " << i << ";\n";
194              }
195            } else if (FieldInit *FI = dynamic_cast<FieldInit*>(TI)) {
196              // FIXME: implement this!
197              o << "FIELD INIT not implemented yet!\n";
198            } else {
199              o << "Error: UNIMPLEMENTED\n";
200            }
201          }
202        }
203      } else {
204        // ignore annul and predict bits since no one sets them yet
205        if (Vals[f].getName() == "annul" || Vals[f].getName() == "predict") {
206          o << "      // found " << Vals[f].getName() << "\n";
207        }
208      }
209    }
210
211    o << "      break;\n"
212      << "    }\n";
213  }
214
215  o << "  default:\n"
216    << "    DEBUG(std::cerr << \"Not supported instr: \" << MI << \"\\n\");\n"
217    << "    abort();\n"
218    << "  }\n"
219    << "  return Value;\n"
220    << "}\n";
221}
222