//===- CodeEmitterGen.cpp - Code Emitter Generator ------------------------===//
//
-// FIXME: Document.
+// 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 "Support/Debug.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
+
+ // 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();
+ }
+ }
+ }
+ }
+ }
+}
+
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) {
Record *R = *I;
BitsInit *BI = R->getValueAsBitsInit("Inst");
+ // 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();
DEBUG(o << " // " << *R->getValue("Inst") << "\n");
o << " Value = " << Value << "U;\n\n";
-
- // Loop over all of the fields in the instruction determining which are the
- // operands to the instruction.
- //
+
+ // Loop over all of the fields in the instruction, determining which are the
+ // operands to the instruction.
unsigned op = 0;
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].getPrefix() && !Vals[i].getValue()->isComplete()) {
+ 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;
+ // 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;
// this is not an operand!!
if (beginBitInInst != -1) {
o << " // op" << op << ": " << Vals[i].getName() << "\n"
- << " int64_t op" << op
+ << " int op" << op
<<" = getMachineOpValue(MI, MI.getOperand("<<op<<"));\n";
//<< " MachineOperand &op" << op <<" = MI.getOperand("<<op<<");\n";
OpOrder[Vals[i].getName()] = op++;
-
- DEBUG(o << " // Var: begin = " << beginBitInVar
+
+ 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)
+ assert(endBitInVar >= 0 && "Negative shift amount in masking!");
if (endBitInVar != 0) {
o << " op" << OpOrder[Vals[i].getName()]
<< " >>= " << endBitInVar << ";\n";
beginBitInVar -= endBitInVar;
endBitInVar = 0;
}
-
+
// High mask
o << " op" << OpOrder[Vals[i].getName()]
<< " &= (1<<" << beginBitInVar+1 << ") - 1;\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";
}
-
+
// otherwise, will be taken care of in the loop below using this
// value:
OpContinuous[Vals[i].getName()] = continuous;
}
}
- 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";
- }
- }
- }
- }
- }
+ 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";
}
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