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eabaed26c3
llvm-6502/utils/TableGen/FastISelEmitter.cpp
Dan Gohman eabaed26c3 Give FunctionLoweringInfo an MBB member, avoiding the need to pass it 
around everywhere, and also give it an InsertPt member, to enable isel
to operate at an arbitrary position within a block, rather than just
appending to a block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107791 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-07 16:47:08 +00:00

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//===- FastISelEmitter.cpp - Generate an instruction selector -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits code for use by the "fast" instruction
// selection algorithm. See the comments at the top of
// lib/CodeGen/SelectionDAG/FastISel.cpp for background.
//
// This file scans through the target's tablegen instruction-info files
// and extracts instructions with obvious-looking patterns, and it emits
// code to look up these instructions by type and operator.
//
//===----------------------------------------------------------------------===//
#include "FastISelEmitter.h"
#include "Record.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/VectorExtras.h"
using namespace llvm;
namespace {
/// InstructionMemo - This class holds additional information about an
/// instruction needed to emit code for it.
///
struct InstructionMemo {
std::string Name;
const CodeGenRegisterClass *RC;
std::string SubRegNo;
std::vector<std::string>* PhysRegs;
};
/// OperandsSignature - This class holds a description of a list of operand
/// types. It has utility methods for emitting text based on the operands.
///
struct OperandsSignature {
std::vector<std::string> Operands;
bool operator<(const OperandsSignature &O) const {
return Operands < O.Operands;
}
bool empty() const { return Operands.empty(); }
/// initialize - Examine the given pattern and initialize the contents
/// of the Operands array accordingly. Return true if all the operands
/// are supported, false otherwise.
///
bool initialize(TreePatternNode *InstPatNode,
const CodeGenTarget &Target,
MVT::SimpleValueType VT) {
if (!InstPatNode->isLeaf()) {
if (InstPatNode->getOperator()->getName() == "imm") {
Operands.push_back("i");
return true;
}
if (InstPatNode->getOperator()->getName() == "fpimm") {
Operands.push_back("f");
return true;
}
}
const CodeGenRegisterClass *DstRC = 0;
for (unsigned i = 0, e = InstPatNode->getNumChildren(); i != e; ++i) {
TreePatternNode *Op = InstPatNode->getChild(i);
// For now, filter out any operand with a predicate.
// For now, filter out any operand with multiple values.
if (!Op->getPredicateFns().empty() ||
Op->getNumTypes() != 1)
return false;
assert(Op->hasTypeSet(0) && "Type infererence not done?");
// For now, all the operands must have the same type.
if (Op->getType(0) != VT)
return false;
if (!Op->isLeaf()) {
if (Op->getOperator()->getName() == "imm") {
Operands.push_back("i");
continue;
}
if (Op->getOperator()->getName() == "fpimm") {
Operands.push_back("f");
continue;
}
// For now, ignore other non-leaf nodes.
return false;
}
DefInit *OpDI = dynamic_cast<DefInit*>(Op->getLeafValue());
if (!OpDI)
return false;
Record *OpLeafRec = OpDI->getDef();
// For now, the only other thing we accept is register operands.
const CodeGenRegisterClass *RC = 0;
if (OpLeafRec->isSubClassOf("RegisterClass"))
RC = &Target.getRegisterClass(OpLeafRec);
else if (OpLeafRec->isSubClassOf("Register"))
RC = Target.getRegisterClassForRegister(OpLeafRec);
else
return false;
// For now, require the register operands' register classes to all
// be the same.
if (!RC)
return false;
// For now, all the operands must have the same register class.
if (DstRC) {
if (DstRC != RC)
return false;
} else
DstRC = RC;
Operands.push_back("r");
}
return true;
}
void PrintParameters(raw_ostream &OS) const {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (Operands[i] == "r") {
OS << "unsigned Op" << i << ", bool Op" << i << "IsKill";
} else if (Operands[i] == "i") {
OS << "uint64_t imm" << i;
} else if (Operands[i] == "f") {
OS << "ConstantFP *f" << i;
} else {
assert("Unknown operand kind!");
abort();
}
if (i + 1 != e)
OS << ", ";
}
}
void PrintArguments(raw_ostream &OS,
const std::vector<std::string>& PR) const {
assert(PR.size() == Operands.size());
bool PrintedArg = false;
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (PR[i] != "")
// Implicit physical register operand.
continue;
if (PrintedArg)
OS << ", ";
if (Operands[i] == "r") {
OS << "Op" << i << ", Op" << i << "IsKill";
PrintedArg = true;
} else if (Operands[i] == "i") {
OS << "imm" << i;
PrintedArg = true;
} else if (Operands[i] == "f") {
OS << "f" << i;
PrintedArg = true;
} else {
assert("Unknown operand kind!");
abort();
}
}
}
void PrintArguments(raw_ostream &OS) const {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (Operands[i] == "r") {
OS << "Op" << i << ", Op" << i << "IsKill";
} else if (Operands[i] == "i") {
OS << "imm" << i;
} else if (Operands[i] == "f") {
OS << "f" << i;
} else {
assert("Unknown operand kind!");
abort();
}
if (i + 1 != e)
OS << ", ";
}
}
void PrintManglingSuffix(raw_ostream &OS,
const std::vector<std::string>& PR) const {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (PR[i] != "")
// Implicit physical register operand. e.g. Instruction::Mul expect to
// select to a binary op. On x86, mul may take a single operand with
// the other operand being implicit. We must emit something that looks
// like a binary instruction except for the very inner FastEmitInst_*
// call.
continue;
OS << Operands[i];
}
}
void PrintManglingSuffix(raw_ostream &OS) const {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
OS << Operands[i];
}
}
};
class FastISelMap {
typedef std::map<std::string, InstructionMemo> PredMap;
typedef std::map<MVT::SimpleValueType, PredMap> RetPredMap;
typedef std::map<MVT::SimpleValueType, RetPredMap> TypeRetPredMap;
typedef std::map<std::string, TypeRetPredMap> OpcodeTypeRetPredMap;
typedef std::map<OperandsSignature, OpcodeTypeRetPredMap> OperandsOpcodeTypeRetPredMap;
OperandsOpcodeTypeRetPredMap SimplePatterns;
std::string InstNS;
public:
explicit FastISelMap(std::string InstNS);
void CollectPatterns(CodeGenDAGPatterns &CGP);
void PrintFunctionDefinitions(raw_ostream &OS);
};
}
static std::string getOpcodeName(Record *Op, CodeGenDAGPatterns &CGP) {
return CGP.getSDNodeInfo(Op).getEnumName();
}
static std::string getLegalCName(std::string OpName) {
std::string::size_type pos = OpName.find("::");
if (pos != std::string::npos)
OpName.replace(pos, 2, "_");
return OpName;
}
FastISelMap::FastISelMap(std::string instns)
: InstNS(instns) {
}
void FastISelMap::CollectPatterns(CodeGenDAGPatterns &CGP) {
const CodeGenTarget &Target = CGP.getTargetInfo();
// Determine the target's namespace name.
InstNS = Target.getInstNamespace() + "::";
assert(InstNS.size() > 2 && "Can't determine target-specific namespace!");
// Scan through all the patterns and record the simple ones.
for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(),
E = CGP.ptm_end(); I != E; ++I) {
const PatternToMatch &Pattern = *I;
// For now, just look at Instructions, so that we don't have to worry
// about emitting multiple instructions for a pattern.
TreePatternNode *Dst = Pattern.getDstPattern();
if (Dst->isLeaf()) continue;
Record *Op = Dst->getOperator();
if (!Op->isSubClassOf("Instruction"))
continue;
CodeGenInstruction &II = CGP.getTargetInfo().getInstruction(Op);
if (II.OperandList.empty())
continue;
// For now, ignore multi-instruction patterns.
bool MultiInsts = false;
for (unsigned i = 0, e = Dst->getNumChildren(); i != e; ++i) {
TreePatternNode *ChildOp = Dst->getChild(i);
if (ChildOp->isLeaf())
continue;
if (ChildOp->getOperator()->isSubClassOf("Instruction")) {
MultiInsts = true;
break;
}
}
if (MultiInsts)
continue;
// For now, ignore instructions where the first operand is not an
// output register.
const CodeGenRegisterClass *DstRC = 0;
std::string SubRegNo;
if (Op->getName() != "EXTRACT_SUBREG") {
Record *Op0Rec = II.OperandList[0].Rec;
if (!Op0Rec->isSubClassOf("RegisterClass"))
continue;
DstRC = &Target.getRegisterClass(Op0Rec);
if (!DstRC)
continue;
} else {
DefInit *SR = dynamic_cast<DefInit*>(Dst->getChild(1)->getLeafValue());
if (SR)
SubRegNo = getQualifiedName(SR->getDef());
else
SubRegNo = Dst->getChild(1)->getLeafValue()->getAsString();
}
// Inspect the pattern.
TreePatternNode *InstPatNode = Pattern.getSrcPattern();
if (!InstPatNode) continue;
if (InstPatNode->isLeaf()) continue;
// Ignore multiple result nodes for now.
if (InstPatNode->getNumTypes() > 1) continue;
Record *InstPatOp = InstPatNode->getOperator();
std::string OpcodeName = getOpcodeName(InstPatOp, CGP);
MVT::SimpleValueType RetVT = MVT::isVoid;
if (InstPatNode->getNumTypes()) RetVT = InstPatNode->getType(0);
MVT::SimpleValueType VT = RetVT;
if (InstPatNode->getNumChildren()) {
assert(InstPatNode->getChild(0)->getNumTypes() == 1);
VT = InstPatNode->getChild(0)->getType(0);
}
// For now, filter out instructions which just set a register to
// an Operand or an immediate, like MOV32ri.
if (InstPatOp->isSubClassOf("Operand"))
continue;
// For now, filter out any instructions with predicates.
if (!InstPatNode->getPredicateFns().empty())
continue;
// Check all the operands.
OperandsSignature Operands;
if (!Operands.initialize(InstPatNode, Target, VT))
continue;
std::vector<std::string>* PhysRegInputs = new std::vector<std::string>();
if (!InstPatNode->isLeaf() &&
(InstPatNode->getOperator()->getName() == "imm" ||
InstPatNode->getOperator()->getName() == "fpimmm"))
PhysRegInputs->push_back("");
else if (!InstPatNode->isLeaf()) {
for (unsigned i = 0, e = InstPatNode->getNumChildren(); i != e; ++i) {
TreePatternNode *Op = InstPatNode->getChild(i);
if (!Op->isLeaf()) {
PhysRegInputs->push_back("");
continue;
}
DefInit *OpDI = dynamic_cast<DefInit*>(Op->getLeafValue());
Record *OpLeafRec = OpDI->getDef();
std::string PhysReg;
if (OpLeafRec->isSubClassOf("Register")) {
PhysReg += static_cast<StringInit*>(OpLeafRec->getValue( \
"Namespace")->getValue())->getValue();
PhysReg += "::";
std::vector<CodeGenRegister> Regs = Target.getRegisters();
for (unsigned i = 0; i < Regs.size(); ++i) {
if (Regs[i].TheDef == OpLeafRec) {
PhysReg += Regs[i].getName();
break;
}
}
}
PhysRegInputs->push_back(PhysReg);
}
} else
PhysRegInputs->push_back("");
// Get the predicate that guards this pattern.
std::string PredicateCheck = Pattern.getPredicateCheck();
// Ok, we found a pattern that we can handle. Remember it.
InstructionMemo Memo = {
Pattern.getDstPattern()->getOperator()->getName(),
DstRC,
SubRegNo,
PhysRegInputs
};
assert(!SimplePatterns[Operands][OpcodeName][VT][RetVT].count(PredicateCheck) &&
"Duplicate pattern!");
SimplePatterns[Operands][OpcodeName][VT][RetVT][PredicateCheck] = Memo;
}
}
void FastISelMap::PrintFunctionDefinitions(raw_ostream &OS) {
// Now emit code for all the patterns that we collected.
for (OperandsOpcodeTypeRetPredMap::const_iterator OI = SimplePatterns.begin(),
OE = SimplePatterns.end(); OI != OE; ++OI) {
const OperandsSignature &Operands = OI->first;
const OpcodeTypeRetPredMap &OTM = OI->second;
for (OpcodeTypeRetPredMap::const_iterator I = OTM.begin(), E = OTM.end();
I != E; ++I) {
const std::string &Opcode = I->first;
const TypeRetPredMap &TM = I->second;
OS << "// FastEmit functions for " << Opcode << ".\n";
OS << "\n";
// Emit one function for each opcode,type pair.
for (TypeRetPredMap::const_iterator TI = TM.begin(), TE = TM.end();
TI != TE; ++TI) {
MVT::SimpleValueType VT = TI->first;
const RetPredMap &RM = TI->second;
if (RM.size() != 1) {
for (RetPredMap::const_iterator RI = RM.begin(), RE = RM.end();
RI != RE; ++RI) {
MVT::SimpleValueType RetVT = RI->first;
const PredMap &PM = RI->second;
bool HasPred = false;
OS << "unsigned FastEmit_"
<< getLegalCName(Opcode)
<< "_" << getLegalCName(getName(VT))
<< "_" << getLegalCName(getName(RetVT)) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(";
Operands.PrintParameters(OS);
OS << ") {\n";
// Emit code for each possible instruction. There may be
// multiple if there are subtarget concerns.
for (PredMap::const_iterator PI = PM.begin(), PE = PM.end();
PI != PE; ++PI) {
std::string PredicateCheck = PI->first;
const InstructionMemo &Memo = PI->second;
if (PredicateCheck.empty()) {
assert(!HasPred &&
"Multiple instructions match, at least one has "
"a predicate and at least one doesn't!");
} else {
OS << " if (" + PredicateCheck + ") {\n";
OS << " ";
HasPred = true;
}
for (unsigned i = 0; i < Memo.PhysRegs->size(); ++i) {
if ((*Memo.PhysRegs)[i] != "")
OS << " TII.copyRegToReg(*FuncInfo.MBB, FuncInfo.InsertPt, "
<< (*Memo.PhysRegs)[i] << ", Op" << i << ", "
<< "TM.getRegisterInfo()->getPhysicalRegisterRegClass("
<< (*Memo.PhysRegs)[i] << "), "
<< "MRI.getRegClass(Op" << i << "), DL);\n";
}
OS << " return FastEmitInst_";
if (Memo.SubRegNo.empty()) {
Operands.PrintManglingSuffix(OS, *Memo.PhysRegs);
OS << "(" << InstNS << Memo.Name << ", ";
OS << InstNS << Memo.RC->getName() << "RegisterClass";
if (!Operands.empty())
OS << ", ";
Operands.PrintArguments(OS, *Memo.PhysRegs);
OS << ");\n";
} else {
OS << "extractsubreg(" << getName(RetVT);
OS << ", Op0, Op0IsKill, ";
OS << Memo.SubRegNo;
OS << ");\n";
}
if (HasPred)
OS << " }\n";
}
// Return 0 if none of the predicates were satisfied.
if (HasPred)
OS << " return 0;\n";
OS << "}\n";
OS << "\n";
}
// Emit one function for the type that demultiplexes on return type.
OS << "unsigned FastEmit_"
<< getLegalCName(Opcode) << "_"
<< getLegalCName(getName(VT)) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(MVT RetVT";
if (!Operands.empty())
OS << ", ";
Operands.PrintParameters(OS);
OS << ") {\nswitch (RetVT.SimpleTy) {\n";
for (RetPredMap::const_iterator RI = RM.begin(), RE = RM.end();
RI != RE; ++RI) {
MVT::SimpleValueType RetVT = RI->first;
OS << " case " << getName(RetVT) << ": return FastEmit_"
<< getLegalCName(Opcode) << "_" << getLegalCName(getName(VT))
<< "_" << getLegalCName(getName(RetVT)) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(";
Operands.PrintArguments(OS);
OS << ");\n";
}
OS << " default: return 0;\n}\n}\n\n";
} else {
// Non-variadic return type.
OS << "unsigned FastEmit_"
<< getLegalCName(Opcode) << "_"
<< getLegalCName(getName(VT)) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(MVT RetVT";
if (!Operands.empty())
OS << ", ";
Operands.PrintParameters(OS);
OS << ") {\n";
OS << " if (RetVT.SimpleTy != " << getName(RM.begin()->first)
<< ")\n return 0;\n";
const PredMap &PM = RM.begin()->second;
bool HasPred = false;
// Emit code for each possible instruction. There may be
// multiple if there are subtarget concerns.
for (PredMap::const_iterator PI = PM.begin(), PE = PM.end(); PI != PE;
++PI) {
std::string PredicateCheck = PI->first;
const InstructionMemo &Memo = PI->second;
if (PredicateCheck.empty()) {
assert(!HasPred &&
"Multiple instructions match, at least one has "
"a predicate and at least one doesn't!");
} else {
OS << " if (" + PredicateCheck + ") {\n";
OS << " ";
HasPred = true;
}
for (unsigned i = 0; i < Memo.PhysRegs->size(); ++i) {
if ((*Memo.PhysRegs)[i] != "")
OS << " TII.copyRegToReg(*FuncInfo.MBB, FuncInfo.InsertPt, "
<< (*Memo.PhysRegs)[i] << ", Op" << i << ", "
<< "TM.getRegisterInfo()->getPhysicalRegisterRegClass("
<< (*Memo.PhysRegs)[i] << "), "
<< "MRI.getRegClass(Op" << i << "), DL);\n";
}
OS << " return FastEmitInst_";
if (Memo.SubRegNo.empty()) {
Operands.PrintManglingSuffix(OS, *Memo.PhysRegs);
OS << "(" << InstNS << Memo.Name << ", ";
OS << InstNS << Memo.RC->getName() << "RegisterClass";
if (!Operands.empty())
OS << ", ";
Operands.PrintArguments(OS, *Memo.PhysRegs);
OS << ");\n";
} else {
OS << "extractsubreg(RetVT, Op0, Op0IsKill, ";
OS << Memo.SubRegNo;
OS << ");\n";
}
if (HasPred)
OS << " }\n";
}
// Return 0 if none of the predicates were satisfied.
if (HasPred)
OS << " return 0;\n";
OS << "}\n";
OS << "\n";
}
}
// Emit one function for the opcode that demultiplexes based on the type.
OS << "unsigned FastEmit_"
<< getLegalCName(Opcode) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(MVT VT, MVT RetVT";
if (!Operands.empty())
OS << ", ";
Operands.PrintParameters(OS);
OS << ") {\n";
OS << " switch (VT.SimpleTy) {\n";
for (TypeRetPredMap::const_iterator TI = TM.begin(), TE = TM.end();
TI != TE; ++TI) {
MVT::SimpleValueType VT = TI->first;
std::string TypeName = getName(VT);
OS << " case " << TypeName << ": return FastEmit_"
<< getLegalCName(Opcode) << "_" << getLegalCName(TypeName) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(RetVT";
if (!Operands.empty())
OS << ", ";
Operands.PrintArguments(OS);
OS << ");\n";
}
OS << " default: return 0;\n";
OS << " }\n";
OS << "}\n";
OS << "\n";
}
OS << "// Top-level FastEmit function.\n";
OS << "\n";
// Emit one function for the operand signature that demultiplexes based
// on opcode and type.
OS << "unsigned FastEmit_";
Operands.PrintManglingSuffix(OS);
OS << "(MVT VT, MVT RetVT, unsigned Opcode";
if (!Operands.empty())
OS << ", ";
Operands.PrintParameters(OS);
OS << ") {\n";
OS << " switch (Opcode) {\n";
for (OpcodeTypeRetPredMap::const_iterator I = OTM.begin(), E = OTM.end();
I != E; ++I) {
const std::string &Opcode = I->first;
OS << " case " << Opcode << ": return FastEmit_"
<< getLegalCName(Opcode) << "_";
Operands.PrintManglingSuffix(OS);
OS << "(VT, RetVT";
if (!Operands.empty())
OS << ", ";
Operands.PrintArguments(OS);
OS << ");\n";
}
OS << " default: return 0;\n";
OS << " }\n";
OS << "}\n";
OS << "\n";
}
}
void FastISelEmitter::run(raw_ostream &OS) {
const CodeGenTarget &Target = CGP.getTargetInfo();
// Determine the target's namespace name.
std::string InstNS = Target.getInstNamespace() + "::";
assert(InstNS.size() > 2 && "Can't determine target-specific namespace!");
EmitSourceFileHeader("\"Fast\" Instruction Selector for the " +
Target.getName() + " target", OS);
FastISelMap F(InstNS);
F.CollectPatterns(CGP);
F.PrintFunctionDefinitions(OS);
}
FastISelEmitter::FastISelEmitter(RecordKeeper &R)
: Records(R),
CGP(R) {
}
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