//===- PseudoLoweringEmitter.cpp - PseudoLowering Generator -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pseudo-lowering"
#include "CodeGenInstruction.h"
#include "PseudoLoweringEmitter.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Debug.h"
#include <vector>
using namespace llvm;
// FIXME: This pass currently can only expand a pseudo to a single instruction.
// The pseudo expansion really should take a list of dags, not just
// a single dag, so we can do fancier things.
unsigned PseudoLoweringEmitter::
addDagOperandMapping(Record *Rec, DagInit *Dag, CodeGenInstruction &Insn,
IndexedMap<OpData> &OperandMap, unsigned BaseIdx) {
unsigned OpsAdded = 0;
for (unsigned i = 0, e = Dag->getNumArgs(); i != e; ++i) {
if (DefInit *DI = dynamic_cast<DefInit*>(Dag->getArg(i))) {
// Physical register reference. Explicit check for the special case
// "zero_reg" definition.
if (DI->getDef()->isSubClassOf("Register") ||
DI->getDef()->getName() == "zero_reg") {
OperandMap[BaseIdx + i].Kind = OpData::Reg;
OperandMap[BaseIdx + i].Data.Reg = DI->getDef();
++OpsAdded;
continue;
}
// Normal operands should always have the same type, or we have a
// problem.
// FIXME: We probably shouldn't ever get a non-zero BaseIdx here.
assert(BaseIdx == 0 && "Named subargument in pseudo expansion?!");
if (DI->getDef() != Insn.Operands[BaseIdx + i].Rec)
throw TGError(Rec->getLoc(),
"Pseudo operand type '" + DI->getDef()->getName() +
"' does not match expansion operand type '" +
Insn.Operands[BaseIdx + i].Rec->getName() + "'");
// Source operand maps to destination operand. The Data element
// will be filled in later, just set the Kind for now. Do it
// for each corresponding MachineInstr operand, not just the first.
for (unsigned I = 0, E = Insn.Operands[i].MINumOperands; I != E; ++I)
OperandMap[BaseIdx + i + I].Kind = OpData::Operand;
OpsAdded += Insn.Operands[i].MINumOperands;
} else if (IntInit *II = dynamic_cast<IntInit*>(Dag->getArg(i))) {
OperandMap[BaseIdx + i].Kind = OpData::Imm;
OperandMap[BaseIdx + i].Data.Imm = II->getValue();
++OpsAdded;
} else if (DagInit *SubDag = dynamic_cast<DagInit*>(Dag->getArg(i))) {
// Just add the operands recursively. This is almost certainly
// a constant value for a complex operand (> 1 MI operand).
unsigned NewOps =
addDagOperandMapping(Rec, SubDag, Insn, OperandMap, BaseIdx + i);
OpsAdded += NewOps;
// Since we added more than one, we also need to adjust the base.
BaseIdx += NewOps - 1;
} else
assert(0 && "Unhandled pseudo-expansion argument type!");
}
return OpsAdded;
}
void PseudoLoweringEmitter::evaluateExpansion(Record *Rec) {
DEBUG(dbgs() << "Pseudo definition: " << Rec->getName() << "\n");
// Validate that the result pattern has the corrent number and types
// of arguments for the instruction it references.
DagInit *Dag = Rec->getValueAsDag("ResultInst");
assert(Dag && "Missing result instruction in pseudo expansion!");
DEBUG(dbgs() << " Result: " << *Dag << "\n");
DefInit *OpDef = dynamic_cast<DefInit*>(Dag->getOperator());
if (!OpDef)
throw TGError(Rec->getLoc(), Rec->getName() +
" has unexpected operator type!");
Record *Operator = OpDef->getDef();
if (!Operator->isSubClassOf("Instruction"))
throw TGError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' is not an instruction!");
CodeGenInstruction Insn(Operator);
if (Insn.isCodeGenOnly || Insn.isPseudo)
throw TGError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' cannot be another pseudo instruction!");
if (Insn.Operands.size() != Dag->getNumArgs())
throw TGError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' operand count mismatch");
IndexedMap<OpData> OperandMap;
OperandMap.grow(Insn.Operands.size());
addDagOperandMapping(Rec, Dag, Insn, OperandMap, 0);
// If there are more operands that weren't in the DAG, they have to
// be operands that have default values, or we have an error. Currently,
// PredicateOperand and OptionalDefOperand both have default values.
// Validate that each result pattern argument has a matching (by name)
// argument in the source instruction, in either the (outs) or (ins) list.
// Also check that the type of the arguments match.
//
// Record the mapping of the source to result arguments for use by
// the lowering emitter.
CodeGenInstruction SourceInsn(Rec);
StringMap<unsigned> SourceOperands;
for (unsigned i = 0, e = SourceInsn.Operands.size(); i != e; ++i)
SourceOperands[SourceInsn.Operands[i].Name] = i;
DEBUG(dbgs() << " Operand mapping:\n");
for (unsigned i = 0, e = Insn.Operands.size(); i != e; ++i) {
// We've already handled constant values. Just map instruction operands
// here.
if (OperandMap[Insn.Operands[i].MIOperandNo].Kind != OpData::Operand)
continue;
StringMap<unsigned>::iterator SourceOp =
SourceOperands.find(Dag->getArgName(i));
if (SourceOp == SourceOperands.end())
throw TGError(Rec->getLoc(),
"Pseudo output operand '" + Dag->getArgName(i) +
"' has no matching source operand.");
// Map the source operand to the destination operand index for each
// MachineInstr operand.
for (unsigned I = 0, E = Insn.Operands[i].MINumOperands; I != E; ++I)
OperandMap[Insn.Operands[i].MIOperandNo + I].Data.Operand =
SourceOp->getValue();
DEBUG(dbgs() << " " << SourceOp->getValue() << " ==> " << i << "\n");
}
Expansions.push_back(PseudoExpansion(SourceInsn, Insn, OperandMap));
}
void PseudoLoweringEmitter::emitLoweringEmitter(raw_ostream &o) {
// Emit file header.
EmitSourceFileHeader("Pseudo-instruction MC lowering Source Fragment", o);
o << "bool " << Target.getName() + "AsmPrinter" << "::\n"
<< "emitPseudoExpansionLowering(MCStreamer &OutStreamer,\n"
<< " const MachineInstr *MI) {\n"
<< " switch (MI->getOpcode()) {\n"
<< " default: return false;\n";
for (unsigned i = 0, e = Expansions.size(); i != e; ++i) {
PseudoExpansion &Expansion = Expansions[i];
CodeGenInstruction &Source = Expansion.Source;
CodeGenInstruction &Dest = Expansion.Dest;
o << " case " << Source.Namespace << "::"
<< Source.TheDef->getName() << ": {\n"
<< " MCInst TmpInst;\n"
<< " MCOperand MCOp;\n"
<< " TmpInst.setOpcode(" << Dest.Namespace << "::"
<< Dest.TheDef->getName() << ");\n";
// Copy the operands from the source instruction.
// FIXME: Instruction operands with defaults values (predicates and cc_out
// in ARM, for example shouldn't need explicit values in the
// expansion DAG.
unsigned MIOpNo = 0;
for (unsigned OpNo = 0, E = Dest.Operands.size(); OpNo != E;
++OpNo) {
o << " // Operand: " << Dest.Operands[OpNo].Name << "\n";
for (unsigned i = 0, e = Dest.Operands[OpNo].MINumOperands;
i != e; ++i) {
switch (Expansion.OperandMap[MIOpNo + i].Kind) {
default:
llvm_unreachable("Unknown operand type?!");
case OpData::Operand:
o << " lowerOperand(MI->getOperand("
<< Source.Operands[Expansion.OperandMap[MIOpNo].Data
.Operand].MIOperandNo + i
<< "), MCOp);\n"
<< " TmpInst.addOperand(MCOp);\n";
break;
case OpData::Imm:
o << " TmpInst.addOperand(MCOperand::CreateImm("
<< Expansion.OperandMap[MIOpNo + i].Data.Imm << "));\n";
break;
case OpData::Reg: {
Record *Reg = Expansion.OperandMap[MIOpNo + i].Data.Reg;
o << " TmpInst.addOperand(MCOperand::CreateReg(";
// "zero_reg" is special.
if (Reg->getName() == "zero_reg")
o << "0";
else
o << Reg->getValueAsString("Namespace") << "::" << Reg->getName();
o << "));\n";
break;
}
}
}
MIOpNo += Dest.Operands[OpNo].MINumOperands;
}
if (Dest.Operands.isVariadic) {
o << " // variable_ops\n";
o << " for (unsigned i = " << MIOpNo
<< ", e = MI->getNumOperands(); i != e; ++i)\n"
<< " if (lowerOperand(MI->getOperand(i), MCOp))\n"
<< " TmpInst.addOperand(MCOp);\n";
}
o << " OutStreamer.EmitInstruction(TmpInst);\n"
<< " break;\n"
<< " }\n";
}
o << " }\n return true;\n}\n\n";
}
void PseudoLoweringEmitter::run(raw_ostream &o) {
Record *ExpansionClass = Records.getClass("PseudoInstExpansion");
Record *InstructionClass = Records.getClass("PseudoInstExpansion");
assert(ExpansionClass && "PseudoInstExpansion class definition missing!");
assert(InstructionClass && "Instruction class definition missing!");
std::vector<Record*> Insts;
for (std::map<std::string, Record*>::const_iterator I =
Records.getDefs().begin(), E = Records.getDefs().end(); I != E; ++I) {
if (I->second->isSubClassOf(ExpansionClass) &&
I->second->isSubClassOf(InstructionClass))
Insts.push_back(I->second);
}
// Process the pseudo expansion definitions, validating them as we do so.
for (unsigned i = 0, e = Insts.size(); i != e; ++i)
evaluateExpansion(Insts[i]);
// Generate expansion code to lower the pseudo to an MCInst of the real
// instruction.
emitLoweringEmitter(o);
}