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llvm-mirror/utils/TableGen/PseudoLoweringEmitter.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo 
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

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//===- PseudoLoweringEmitter.cpp - PseudoLowering Generator -----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "CodeGenInstruction.h"
#include "CodeGenTarget.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/TableGenBackend.h"
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "pseudo-lowering"
namespace {
class PseudoLoweringEmitter {
struct OpData {
enum MapKind { Operand, Imm, Reg };
MapKind Kind;
union {
unsigned Operand; // Operand number mapped to.
uint64_t Imm; // Integer immedate value.
Record *Reg; // Physical register.
} Data;
};
struct PseudoExpansion {
CodeGenInstruction Source; // The source pseudo instruction definition.
CodeGenInstruction Dest; // The destination instruction to lower to.
IndexedMap<OpData> OperandMap;
PseudoExpansion(CodeGenInstruction &s, CodeGenInstruction &d,
IndexedMap<OpData> &m) :
Source(s), Dest(d), OperandMap(m) {}
};
RecordKeeper &Records;
// It's overkill to have an instance of the full CodeGenTarget object,
// but it loads everything on demand, not in the constructor, so it's
// lightweight in performance, so it works out OK.
CodeGenTarget Target;
SmallVector<PseudoExpansion, 64> Expansions;
unsigned addDagOperandMapping(Record *Rec, DagInit *Dag,
CodeGenInstruction &Insn,
IndexedMap<OpData> &OperandMap,
unsigned BaseIdx);
void evaluateExpansion(Record *Pseudo);
void emitLoweringEmitter(raw_ostream &o);
public:
PseudoLoweringEmitter(RecordKeeper &R) : Records(R), Target(R) {}
/// run - Output the pseudo-lowerings.
void run(raw_ostream &o);
};
} // End anonymous namespace
// 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 = dyn_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)
PrintFatalError(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 = dyn_cast<IntInit>(Dag->getArg(i))) {
OperandMap[BaseIdx + i].Kind = OpData::Imm;
OperandMap[BaseIdx + i].Data.Imm = II->getValue();
++OpsAdded;
} else if (DagInit *SubDag = dyn_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
llvm_unreachable("Unhandled pseudo-expansion argument type!");
}
return OpsAdded;
}
void PseudoLoweringEmitter::evaluateExpansion(Record *Rec) {
LLVM_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!");
LLVM_DEBUG(dbgs() << " Result: " << *Dag << "\n");
DefInit *OpDef = dyn_cast<DefInit>(Dag->getOperator());
if (!OpDef)
PrintFatalError(Rec->getLoc(), Rec->getName() +
" has unexpected operator type!");
Record *Operator = OpDef->getDef();
if (!Operator->isSubClassOf("Instruction"))
PrintFatalError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' is not an instruction!");
CodeGenInstruction Insn(Operator);
if (Insn.isCodeGenOnly || Insn.isPseudo)
PrintFatalError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' cannot be another pseudo instruction!");
if (Insn.Operands.size() != Dag->getNumArgs())
PrintFatalError(Rec->getLoc(), "Pseudo result '" + Operator->getName() +
"' operand count mismatch");
unsigned NumMIOperands = 0;
for (unsigned i = 0, e = Insn.Operands.size(); i != e; ++i)
NumMIOperands += Insn.Operands[i].MINumOperands;
IndexedMap<OpData> OperandMap;
OperandMap.grow(NumMIOperands);
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,
// Operands that are a subclass of OperandWithDefaultOp 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;
LLVM_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->getArgNameStr(i));
if (SourceOp == SourceOperands.end())
PrintFatalError(Rec->getLoc(),
"Pseudo output operand '" + Dag->getArgNameStr(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();
LLVM_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";
if (!Expansions.empty()) {
o << " switch (MI->getOpcode()) {\n"
<< " default: return false;\n";
for (auto &Expansion : Expansions) {
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 (const auto &DestOperand : Dest.Operands) {
o << " // Operand: " << DestOperand.Name << "\n";
for (unsigned i = 0, e = DestOperand.MINumOperands; i != e; ++i) {
switch (Expansion.OperandMap[MIOpNo + i].Kind) {
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 += DestOperand.MINumOperands;
}
if (Dest.Operands.isVariadic) {
MIOpNo = Source.Operands.size() + 1;
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 << " EmitToStreamer(OutStreamer, TmpInst);\n"
<< " break;\n"
<< " }\n";
}
o << " }\n return true;";
} else
o << " return false;";
o << "\n}\n\n";
}
void PseudoLoweringEmitter::run(raw_ostream &o) {
Record *ExpansionClass = Records.getClass("PseudoInstExpansion");
Record *InstructionClass = Records.getClass("Instruction");
assert(ExpansionClass && "PseudoInstExpansion class definition missing!");
assert(InstructionClass && "Instruction class definition missing!");
std::vector<Record*> Insts;
for (const auto &D : Records.getDefs()) {
if (D.second->isSubClassOf(ExpansionClass) &&
D.second->isSubClassOf(InstructionClass))
Insts.push_back(D.second.get());
}
// 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);
}
namespace llvm {
void EmitPseudoLowering(RecordKeeper &RK, raw_ostream &OS) {
PseudoLoweringEmitter(RK).run(OS);
}
} // End llvm namespace
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