Added a break that I meant to include originally, for efficiency. Basically
[oota-llvm.git] / utils / TableGen / CodeEmitterGen.cpp
index 90497cc620bfeb0d46e795f13d6b35a1361ae66f..ef3a6e9ad5b6352f8a051c470be7a1ae54a80cd3 100644 (file)
-#include "Support/Statistic.h"
-#include "Record.h"
+//===- CodeEmitterGen.cpp - Code Emitter Generator ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// CodeEmitterGen uses the descriptions of instructions and their fields to
+// construct an automated code emitter: a function that, given a MachineInstr,
+// returns the (currently, 32-bit unsigned) value of the instruction.
+//
+//===----------------------------------------------------------------------===//
+
 #include "CodeEmitterGen.h"
+#include "CodeGenTarget.h"
+#include "Record.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+
+void CodeEmitterGen::emitInstrOpBits(std::ostream &o,
+                                     const std::vector<RecordVal> &Vals,
+                                     std::map<std::string, unsigned> &OpOrder,
+                                     std::map<std::string, bool> &OpContinuous)
+{
+  for (unsigned f = 0, e = Vals.size(); f != e; ++f) {
+    if (Vals[f].getPrefix()) {
+      BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue();
+
+      // Scan through the field looking for bit initializers of the current
+      // variable...
+      for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) {
+        Init *I = FieldInitializer->getBit(i);
+        if (BitInit *BI = dynamic_cast<BitInit*>(I)) {
+          DEBUG(o << "      // bit init: f: " << f << ", i: " << i << "\n");
+        } else if (UnsetInit *UI = dynamic_cast<UnsetInit*>(I)) {
+          DEBUG(o << "      // unset init: f: " << f << ", i: " << i << "\n");
+        } else if (VarBitInit *VBI = dynamic_cast<VarBitInit*>(I)) {
+          TypedInit *TI = VBI->getVariable();
+          if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
+            // If the bits of the field are laid out consecutively in the
+            // instruction, then instead of separately ORing in bits, just
+            // mask and shift the entire field for efficiency.
+            if (OpContinuous[VI->getName()]) {
+              // already taken care of in the loop above, thus there is no
+              // need to individually OR in the bits
 
-void CodeEmitterGen::createEmitter(std::ostream &o) {
-  std::vector<Record*> Insts;
+              // for debugging, output the regular version anyway, commented
+              DEBUG(o << "      // Value |= getValueBit(op"
+                      << OpOrder[VI->getName()] << ", " << VBI->getBitNum()
+                      << ")" << " << " << i << ";\n");
+            } else {
+              o << "      Value |= getValueBit(op" << OpOrder[VI->getName()]
+                << ", " << VBI->getBitNum()
+                << ")" << " << " << i << ";\n";
+            }
+          } else if (FieldInit *FI = dynamic_cast<FieldInit*>(TI)) {
+            // FIXME: implement this!
+            std::cerr << "Error: FieldInit not implemented!\n";
+            abort();
+          } else {
+            std::cerr << "Error: unimplemented case in "
+                      << "CodeEmitterGen::emitInstrOpBits()\n";
+            abort();
+          }
+        }
+      }
+    }
+  }
+}
 
-  const std::map<std::string, Record*> &Defs = Records.getDefs();
-  Record *Inst = Records.getClass("Instruction");
-  assert(Inst && "Couldn't find Instruction class!");
 
-  for (std::map<std::string, Record*>::const_iterator I = Defs.begin(),
-        E = Defs.end(); I != E; ++I)
-    if (I->second->isSubClassOf(Inst))
-      Insts.push_back(I->second);
+void CodeEmitterGen::run(std::ostream &o) {
+  CodeGenTarget Target;
+  std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
 
-  std::string Namespace = "V9::";
-  std::string ClassName = "SparcV9CodeEmitter::";
+  EmitSourceFileHeader("Machine Code Emitter", o);
+  std::string Namespace = Insts[0]->getValueAsString("Namespace") + "::";
 
-  //const std::string &Namespace = Inst->getValue("Namespace")->getName();
-  o << "unsigned " << ClassName
+  // Emit function declaration
+  o << "unsigned " << Target.getName() << "CodeEmitter::"
     << "getBinaryCodeForInstr(MachineInstr &MI) {\n"
     << "  unsigned Value = 0;\n"
     << "  DEBUG(std::cerr << MI);\n"
     << "  switch (MI.getOpcode()) {\n";
+
+  // Emit a case statement for each opcode
   for (std::vector<Record*>::iterator I = Insts.begin(), E = Insts.end();
-       I != E; ++I)
-  {
+       I != E; ++I) {
     Record *R = *I;
     o << "    case " << Namespace << R->getName() << ": {\n"
       << "      DEBUG(std::cerr << \"Emitting " << R->getName() << "\\n\");\n";
 
-    const RecordVal *InstVal = R->getValue("Inst");
-    Init *InitVal = InstVal->getValue();
+    BitsInit *BI = R->getValueAsBitsInit("Inst");
 
-    assert(dynamic_cast<BitsInit*>(InitVal) &&
-           "Can only handle undefined bits<> types!");
-    BitsInit *BI = (BitsInit*)InitVal;
+    // For little-endian instruction bit encodings, reverse the bit order
+    if (Target.isLittleEndianEncoding()) {
+      unsigned numBits = BI->getNumBits();
+      BitsInit *NewBI = new BitsInit(numBits);
+      for (unsigned bit = 0, end = numBits / 2; bit != end; ++bit) {
+        unsigned bitSwapIdx = numBits - bit - 1;
+        Init *OrigBit = BI->getBit(bit);
+        Init *BitSwap = BI->getBit(bitSwapIdx);
+        NewBI->setBit(bit, BitSwap);
+        NewBI->setBit(bitSwapIdx, OrigBit);
+      }
+      if (numBits % 2) {
+        unsigned middle = (numBits + 1) / 2;
+        NewBI->setBit(middle, BI->getBit(middle));
+      }
+      BI = NewBI;
+    }
 
     unsigned Value = 0;
     const std::vector<RecordVal> &Vals = R->getValues();
@@ -52,33 +127,21 @@ void CodeEmitterGen::createEmitter(std::ostream &o) {
     }
     DEBUG(o << "\n");
 
-    DEBUG(o << "      // " << *InstVal << "\n");
+    DEBUG(o << "      // " << *R->getValue("Inst") << "\n");
     o << "      Value = " << Value << "U;\n\n";
-    
-    // Loop over all of the fields in the instruction adding in any
-    // contributions to this value (due to bit references).
-    //
+
+    // Loop over all of the fields in the instruction, determining which are the
+    // operands to the instruction.
     unsigned op = 0;
-    std::map<const std::string,unsigned> OpOrder;
-    std::map<const std::string,bool> OpContinuous;
+    std::map<std::string, unsigned> OpOrder;
+    std::map<std::string, bool> OpContinuous;
     for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
-      if (Vals[i].getName() != "Inst" && 
-          !Vals[i].getValue()->isComplete() &&
-          /* ignore annul and predict bits since no one sets them yet */
-          Vals[i].getName() != "annul" && 
-          Vals[i].getName() != "predict")
-      {
-        o << "      // op" << op << ": " << Vals[i].getName() << "\n"
-          << "      int64_t op" << op 
-          <<" = getMachineOpValue(MI, MI.getOperand("<<op<<"));\n";
-        //<< "      MachineOperand &op" << op <<" = MI.getOperand("<<op<<");\n";
-        OpOrder[Vals[i].getName()] = op++;
-
+      if (!Vals[i].getPrefix() && !Vals[i].getValue()->isComplete()) {
         // Is the operand continuous? If so, we can just mask and OR it in
-        // instead of doing it bit-by-bit, saving a lot in runtime cost.        
-        const BitsInit *InstInit = BI;
-        int beginBitInVar = -1, endBitInVar = -1,
-          beginBitInInst = -1, endBitInInst = -1;
+        // instead of doing it bit-by-bit, saving a lot in runtime cost.
+        BitsInit *InstInit = BI;
+        int beginBitInVar = -1, endBitInVar = -1;
+        int beginBitInInst = -1, endBitInInst = -1;
         bool continuous = true;
 
         for (int bit = InstInit->getNumBits()-1; bit >= 0; --bit) {
@@ -120,9 +183,8 @@ void CodeEmitterGen::createEmitter(std::ostream &o) {
               // maintain same distance between bits in field and bits in
               // instruction. if the relative distances stay the same
               // throughout,
-              if ((beginBitInVar - (int)VBI->getBitNum()) !=
-                  (beginBitInInst - bit))
-              {
+              if (beginBitInVar - (int)VBI->getBitNum() !=
+                  beginBitInInst - bit) {
                 continuous = false;
                 break;
               }
@@ -130,99 +192,66 @@ void CodeEmitterGen::createEmitter(std::ostream &o) {
           }
         }
 
-        DEBUG(o << "      // Var: begin = " << beginBitInVar 
-                << ", end = " << endBitInVar
-                << "; Inst: begin = " << beginBitInInst
-                << ", end = " << endBitInInst << "\n");
-
-        if (continuous) {
-          DEBUG(o << "      // continuous: op" << OpOrder[Vals[i].getName()]
-                  << "\n");
-          
-          // Mask off the right bits
-          // Low mask (ie. shift, if necessary)
-          if (endBitInVar != 0) {
-            o << "      op" << OpOrder[Vals[i].getName()]
-              << " >>= " << endBitInVar << ";\n";
-            beginBitInVar -= endBitInVar;
-            endBitInVar = 0;
-          }
+        // If we have found no bit in "Inst" which comes from this field, then
+        // this is not an operand!!
+        if (beginBitInInst != -1) {
+          o << "      // op" << op << ": " << Vals[i].getName() << "\n"
+            << "      int op" << op
+            <<" = getMachineOpValue(MI, MI.getOperand("<<op<<"));\n";
+          //<< "   MachineOperand &op" << op <<" = MI.getOperand("<<op<<");\n";
+          OpOrder[Vals[i].getName()] = op++;
 
-          // High mask
-          o << "      op" << OpOrder[Vals[i].getName()]
-            << " &= (1<<" << beginBitInVar+1 << ") - 1;\n";
+          DEBUG(o << "      // Var: begin = " << beginBitInVar
+                  << ", end = " << endBitInVar
+                  << "; Inst: begin = " << beginBitInInst
+                  << ", end = " << endBitInInst << "\n");
 
-          // Shift the value to the correct place (according to place in instr)
-          if (endBitInInst != 0)
-            o << "      op" << OpOrder[Vals[i].getName()]
-              << " <<= " << endBitInInst << ";\n";
+          if (continuous) {
+            DEBUG(o << "      // continuous: op" << OpOrder[Vals[i].getName()]
+                    << "\n");
 
-          // Just OR in the result
-          o << "      Value |= op" << OpOrder[Vals[i].getName()] << ";\n";
-        }
+            // Mask off the right bits
+            // Low mask (ie. shift, if necessary)
+            assert(endBitInVar >= 0 && "Negative shift amount in masking!");
+            if (endBitInVar != 0) {
+              o << "      op" << OpOrder[Vals[i].getName()]
+                << " >>= " << endBitInVar << ";\n";
+              beginBitInVar -= endBitInVar;
+              endBitInVar = 0;
+            }
 
-        // otherwise, will be taken care of in the loop below using this value:
-        OpContinuous[Vals[i].getName()] = continuous;
-      }
-    }
+            // High mask
+            o << "      op" << OpOrder[Vals[i].getName()]
+              << " &= (1<<" << beginBitInVar+1 << ") - 1;\n";
 
-    for (unsigned f = 0, e = Vals.size(); f != e; ++f) {
-      if (Vals[f].getPrefix()) {
-        BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue();
-
-        // Scan through the field looking for bit initializers of the current
-        // variable...
-        for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) {
-          if (BitInit *BI=dynamic_cast<BitInit*>(FieldInitializer->getBit(i)))
-          {
-            DEBUG(o << "      // bit init: f: " << f << ", i: " << i << "\n");
-          } else if (UnsetInit *UI =
-                     dynamic_cast<UnsetInit*>(FieldInitializer->getBit(i))) {
-            DEBUG(o << "      // unset init: f: " << f << ", i: " << i << "\n");
-          } else if (VarBitInit *VBI =
-                     dynamic_cast<VarBitInit*>(FieldInitializer->getBit(i))) {
-            TypedInit *TI = VBI->getVariable();
-            if (VarInit *VI = dynamic_cast<VarInit*>(TI)) {
-              // If the bits of the field are laid out consecutively in the
-              // instruction, then instead of separately ORing in bits, just
-              // mask and shift the entire field for efficiency.
-              if (OpContinuous[VI->getName()]) {
-                // already taken care of in the loop above, thus there is no
-                // need to individually OR in the bits
-
-                // for debugging, output the regular version anyway, commented
-                DEBUG(o << "      // Value |= getValueBit(op"
-                        << OpOrder[VI->getName()] << ", " << VBI->getBitNum()
-                        << ")" << " << " << i << ";\n");
-              } else {
-                o << "      Value |= getValueBit(op" << OpOrder[VI->getName()]
-                  << ", " << VBI->getBitNum()
-                  << ")" << " << " << i << ";\n";
-              }
-            } else if (FieldInit *FI = dynamic_cast<FieldInit*>(TI)) {
-              // FIXME: implement this!
-              o << "FIELD INIT not implemented yet!\n";
-            } else {
-              o << "Error: UNIMPLEMENTED\n";
-            }
+            // Shift the value to the correct place (according to place in inst)
+            assert(endBitInInst >= 0 && "Negative shift amount!");
+            if (endBitInInst != 0)
+              o << "      op" << OpOrder[Vals[i].getName()]
+              << " <<= " << endBitInInst << ";\n";
+
+            // Just OR in the result
+            o << "      Value |= op" << OpOrder[Vals[i].getName()] << ";\n";
           }
-        }
-      } else {
-        // ignore annul and predict bits since no one sets them yet
-        if (Vals[f].getName() == "annul" || Vals[f].getName() == "predict") {
-          o << "      // found " << Vals[f].getName() << "\n";
+
+          // otherwise, will be taken care of in the loop below using this
+          // value:
+          OpContinuous[Vals[i].getName()] = continuous;
         }
       }
     }
 
+    emitInstrOpBits(o, Vals, OpOrder, OpContinuous);
+
     o << "      break;\n"
       << "    }\n";
   }
 
+  // Default case: unhandled opcode
   o << "  default:\n"
-    << "    DEBUG(std::cerr << \"Not supported instr: \" << MI << \"\\n\");\n"
+    << "    std::cerr << \"Not supported instr: \" << MI << \"\\n\";\n"
     << "    abort();\n"
     << "  }\n"
     << "  return Value;\n"
-    << "}\n";
+    << "}\n\n";
 }