llvm/utils/TableGen/InstrInfoEmitter.cpp
Chris Lattner ba7e756c22 Start inferring side effect information more aggressively, and fix many bugs in the
x86 backend where instructions were not marked maystore/mayload, and perf issues where
instructions were not marked neverHasSideEffects.  It would be really nice if we could
write patterns for copy instructions.

I have audited all the x86 instructions down to MOVDQAmr.  The flags on others and on
other targets are probably not right in all cases, but no clients currently use this
info that are enabled by default.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45829 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-10 07:59:24 +00:00

452 lines
16 KiB
C++

//===- InstrInfoEmitter.cpp - Generate a Instruction Set Desc. ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend is responsible for emitting a description of the target
// instruction set for the code generator.
//
//===----------------------------------------------------------------------===//
#include "InstrInfoEmitter.h"
#include "CodeGenTarget.h"
#include "Record.h"
#include <algorithm>
#include <iostream>
using namespace llvm;
static void PrintDefList(const std::vector<Record*> &Uses,
unsigned Num, std::ostream &OS) {
OS << "static const unsigned ImplicitList" << Num << "[] = { ";
for (unsigned i = 0, e = Uses.size(); i != e; ++i)
OS << getQualifiedName(Uses[i]) << ", ";
OS << "0 };\n";
}
//===----------------------------------------------------------------------===//
// Instruction Itinerary Information.
//===----------------------------------------------------------------------===//
struct RecordNameComparator {
bool operator()(const Record *Rec1, const Record *Rec2) const {
return Rec1->getName() < Rec2->getName();
}
};
void InstrInfoEmitter::GatherItinClasses() {
std::vector<Record*> DefList =
Records.getAllDerivedDefinitions("InstrItinClass");
std::sort(DefList.begin(), DefList.end(), RecordNameComparator());
for (unsigned i = 0, N = DefList.size(); i < N; i++)
ItinClassMap[DefList[i]->getName()] = i;
}
unsigned InstrInfoEmitter::getItinClassNumber(const Record *InstRec) {
return ItinClassMap[InstRec->getValueAsDef("Itinerary")->getName()];
}
//===----------------------------------------------------------------------===//
// Operand Info Emission.
//===----------------------------------------------------------------------===//
std::vector<std::string>
InstrInfoEmitter::GetOperandInfo(const CodeGenInstruction &Inst) {
std::vector<std::string> Result;
for (unsigned i = 0, e = Inst.OperandList.size(); i != e; ++i) {
// Handle aggregate operands and normal operands the same way by expanding
// either case into a list of operands for this op.
std::vector<CodeGenInstruction::OperandInfo> OperandList;
// This might be a multiple operand thing. Targets like X86 have
// registers in their multi-operand operands. It may also be an anonymous
// operand, which has a single operand, but no declared class for the
// operand.
DagInit *MIOI = Inst.OperandList[i].MIOperandInfo;
if (!MIOI || MIOI->getNumArgs() == 0) {
// Single, anonymous, operand.
OperandList.push_back(Inst.OperandList[i]);
} else {
for (unsigned j = 0, e = Inst.OperandList[i].MINumOperands; j != e; ++j) {
OperandList.push_back(Inst.OperandList[i]);
Record *OpR = dynamic_cast<DefInit*>(MIOI->getArg(j))->getDef();
OperandList.back().Rec = OpR;
}
}
for (unsigned j = 0, e = OperandList.size(); j != e; ++j) {
Record *OpR = OperandList[j].Rec;
std::string Res;
if (OpR->isSubClassOf("RegisterClass"))
Res += getQualifiedName(OpR) + "RegClassID, ";
else
Res += "0, ";
// Fill in applicable flags.
Res += "0";
// Ptr value whose register class is resolved via callback.
if (OpR->getName() == "ptr_rc")
Res += "|(1<<TOI::LookupPtrRegClass)";
// Predicate operands. Check to see if the original unexpanded operand
// was of type PredicateOperand.
if (Inst.OperandList[i].Rec->isSubClassOf("PredicateOperand"))
Res += "|(1<<TOI::Predicate)";
// Optional def operands. Check to see if the original unexpanded operand
// was of type OptionalDefOperand.
if (Inst.OperandList[i].Rec->isSubClassOf("OptionalDefOperand"))
Res += "|(1<<TOI::OptionalDef)";
// Fill in constraint info.
Res += ", " + Inst.OperandList[i].Constraints[j];
Result.push_back(Res);
}
}
return Result;
}
void InstrInfoEmitter::EmitOperandInfo(std::ostream &OS,
OperandInfoMapTy &OperandInfoIDs) {
// ID #0 is for no operand info.
unsigned OperandListNum = 0;
OperandInfoIDs[std::vector<std::string>()] = ++OperandListNum;
OS << "\n";
const CodeGenTarget &Target = CDP.getTargetInfo();
for (CodeGenTarget::inst_iterator II = Target.inst_begin(),
E = Target.inst_end(); II != E; ++II) {
std::vector<std::string> OperandInfo = GetOperandInfo(II->second);
unsigned &N = OperandInfoIDs[OperandInfo];
if (N != 0) continue;
N = ++OperandListNum;
OS << "static const TargetOperandInfo OperandInfo" << N << "[] = { ";
for (unsigned i = 0, e = OperandInfo.size(); i != e; ++i)
OS << "{ " << OperandInfo[i] << " }, ";
OS << "};\n";
}
}
//===----------------------------------------------------------------------===//
// Instruction Analysis
//===----------------------------------------------------------------------===//
class InstAnalyzer {
const CodeGenDAGPatterns &CDP;
bool &mayStore;
bool &mayLoad;
bool &HasSideEffects;
public:
InstAnalyzer(const CodeGenDAGPatterns &cdp,
bool &maystore, bool &mayload, bool &hse)
: CDP(cdp), mayStore(maystore), mayLoad(mayload), HasSideEffects(hse){
}
/// Analyze - Analyze the specified instruction, returning true if the
/// instruction had a pattern.
bool Analyze(Record *InstRecord) {
const TreePattern *Pattern = CDP.getInstruction(InstRecord).getPattern();
if (Pattern == 0) {
HasSideEffects = 1;
return false; // No pattern.
}
// FIXME: Assume only the first tree is the pattern. The others are clobber
// nodes.
AnalyzeNode(Pattern->getTree(0));
return true;
}
private:
void AnalyzeNode(const TreePatternNode *N) {
if (N->isLeaf()) {
if (DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue())) {
Record *LeafRec = DI->getDef();
// Handle ComplexPattern leaves.
if (LeafRec->isSubClassOf("ComplexPattern")) {
const ComplexPattern &CP = CDP.getComplexPattern(LeafRec);
if (CP.hasProperty(SDNPMayStore)) mayStore = true;
if (CP.hasProperty(SDNPMayLoad)) mayLoad = true;
if (CP.hasProperty(SDNPSideEffect)) HasSideEffects = true;
}
}
return;
}
// Analyze children.
for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i)
AnalyzeNode(N->getChild(i));
// Ignore set nodes, which are not SDNodes.
if (N->getOperator()->getName() == "set")
return;
// Get information about the SDNode for the operator.
const SDNodeInfo &OpInfo = CDP.getSDNodeInfo(N->getOperator());
// Notice properties of the node.
if (OpInfo.hasProperty(SDNPMayStore)) mayStore = true;
if (OpInfo.hasProperty(SDNPMayLoad)) mayLoad = true;
if (OpInfo.hasProperty(SDNPSideEffect)) HasSideEffects = true;
if (const CodeGenIntrinsic *IntInfo = N->getIntrinsicInfo(CDP)) {
// If this is an intrinsic, analyze it.
if (IntInfo->ModRef >= CodeGenIntrinsic::ReadArgMem)
mayLoad = true;// These may load memory.
if (IntInfo->ModRef >= CodeGenIntrinsic::WriteArgMem)
mayStore = true;// Intrinsics that can write to memory are 'mayStore'.
if (IntInfo->ModRef >= CodeGenIntrinsic::WriteMem)
// WriteMem intrinsics can have other strange effects.
HasSideEffects = true;
}
}
};
void InstrInfoEmitter::InferFromPattern(const CodeGenInstruction &Inst,
bool &MayStore, bool &MayLoad,
bool &HasSideEffects) {
MayStore = MayLoad = HasSideEffects = false;
bool HadPattern =
InstAnalyzer(CDP, MayStore, MayLoad, HasSideEffects).Analyze(Inst.TheDef);
// InstAnalyzer only correctly analyzes mayStore/mayLoad so far.
if (Inst.mayStore) { // If the .td file explicitly sets mayStore, use it.
// If we decided that this is a store from the pattern, then the .td file
// entry is redundant.
if (MayStore)
fprintf(stderr,
"Warning: mayStore flag explicitly set on instruction '%s'"
" but flag already inferred from pattern.\n",
Inst.TheDef->getName().c_str());
MayStore = true;
}
if (Inst.mayLoad) { // If the .td file explicitly sets mayLoad, use it.
// If we decided that this is a load from the pattern, then the .td file
// entry is redundant.
if (MayLoad)
fprintf(stderr,
"Warning: mayLoad flag explicitly set on instruction '%s'"
" but flag already inferred from pattern.\n",
Inst.TheDef->getName().c_str());
MayLoad = true;
}
if (Inst.neverHasSideEffects) {
if (HadPattern)
fprintf(stderr, "Warning: neverHasSideEffects set on instruction '%s' "
"which already has a pattern\n", Inst.TheDef->getName().c_str());
HasSideEffects = false;
}
if (Inst.hasSideEffects) {
if (HasSideEffects)
fprintf(stderr, "Warning: hasSideEffects set on instruction '%s' "
"which already inferred this.\n", Inst.TheDef->getName().c_str());
HasSideEffects = true;
}
}
//===----------------------------------------------------------------------===//
// Main Output.
//===----------------------------------------------------------------------===//
// run - Emit the main instruction description records for the target...
void InstrInfoEmitter::run(std::ostream &OS) {
GatherItinClasses();
EmitSourceFileHeader("Target Instruction Descriptors", OS);
OS << "namespace llvm {\n\n";
CodeGenTarget Target;
const std::string &TargetName = Target.getName();
Record *InstrInfo = Target.getInstructionSet();
// Keep track of all of the def lists we have emitted already.
std::map<std::vector<Record*>, unsigned> EmittedLists;
unsigned ListNumber = 0;
// Emit all of the instruction's implicit uses and defs.
for (CodeGenTarget::inst_iterator II = Target.inst_begin(),
E = Target.inst_end(); II != E; ++II) {
Record *Inst = II->second.TheDef;
std::vector<Record*> Uses = Inst->getValueAsListOfDefs("Uses");
if (!Uses.empty()) {
unsigned &IL = EmittedLists[Uses];
if (!IL) PrintDefList(Uses, IL = ++ListNumber, OS);
}
std::vector<Record*> Defs = Inst->getValueAsListOfDefs("Defs");
if (!Defs.empty()) {
unsigned &IL = EmittedLists[Defs];
if (!IL) PrintDefList(Defs, IL = ++ListNumber, OS);
}
}
OperandInfoMapTy OperandInfoIDs;
// Emit all of the operand info records.
EmitOperandInfo(OS, OperandInfoIDs);
// Emit all of the TargetInstrDesc records in their ENUM ordering.
//
OS << "\nstatic const TargetInstrDesc " << TargetName
<< "Insts[] = {\n";
std::vector<const CodeGenInstruction*> NumberedInstructions;
Target.getInstructionsByEnumValue(NumberedInstructions);
for (unsigned i = 0, e = NumberedInstructions.size(); i != e; ++i)
emitRecord(*NumberedInstructions[i], i, InstrInfo, EmittedLists,
OperandInfoIDs, OS);
OS << "};\n";
OS << "} // End llvm namespace \n";
}
void InstrInfoEmitter::emitRecord(const CodeGenInstruction &Inst, unsigned Num,
Record *InstrInfo,
std::map<std::vector<Record*>, unsigned> &EmittedLists,
const OperandInfoMapTy &OpInfo,
std::ostream &OS) {
// Determine properties of the instruction from its pattern.
bool mayStore, mayLoad, HasSideEffects;
InferFromPattern(Inst, mayStore, mayLoad, HasSideEffects);
int MinOperands = 0;
if (!Inst.OperandList.empty())
// Each logical operand can be multiple MI operands.
MinOperands = Inst.OperandList.back().MIOperandNo +
Inst.OperandList.back().MINumOperands;
OS << " { ";
OS << Num << ",\t" << MinOperands << ",\t"
<< Inst.NumDefs << ",\t" << getItinClassNumber(Inst.TheDef)
<< ",\t\"" << Inst.TheDef->getName() << "\", 0";
// Emit all of the target indepedent flags...
if (Inst.isReturn) OS << "|(1<<TID::Return)";
if (Inst.isBranch) OS << "|(1<<TID::Branch)";
if (Inst.isIndirectBranch) OS << "|(1<<TID::IndirectBranch)";
if (Inst.isBarrier) OS << "|(1<<TID::Barrier)";
if (Inst.hasDelaySlot) OS << "|(1<<TID::DelaySlot)";
if (Inst.isCall) OS << "|(1<<TID::Call)";
if (Inst.isSimpleLoad) OS << "|(1<<TID::SimpleLoad)";
if (mayLoad) OS << "|(1<<TID::MayLoad)";
if (mayStore) OS << "|(1<<TID::MayStore)";
if (Inst.isImplicitDef)OS << "|(1<<TID::ImplicitDef)";
if (Inst.isPredicable) OS << "|(1<<TID::Predicable)";
if (Inst.isConvertibleToThreeAddress) OS << "|(1<<TID::ConvertibleTo3Addr)";
if (Inst.isCommutable) OS << "|(1<<TID::Commutable)";
if (Inst.isTerminator) OS << "|(1<<TID::Terminator)";
if (Inst.isReMaterializable) OS << "|(1<<TID::Rematerializable)";
if (Inst.isNotDuplicable) OS << "|(1<<TID::NotDuplicable)";
if (Inst.hasOptionalDef) OS << "|(1<<TID::HasOptionalDef)";
if (Inst.usesCustomDAGSchedInserter)
OS << "|(1<<TID::UsesCustomDAGSchedInserter)";
if (Inst.isVariadic) OS << "|(1<<TID::Variadic)";
if (Inst.mayHaveSideEffects) OS << "|(1<<TID::MayHaveSideEffects)";
if (!HasSideEffects) OS << "|(1<<TID::NeverHasSideEffects)";
OS << ", 0";
// Emit all of the target-specific flags...
ListInit *LI = InstrInfo->getValueAsListInit("TSFlagsFields");
ListInit *Shift = InstrInfo->getValueAsListInit("TSFlagsShifts");
if (LI->getSize() != Shift->getSize())
throw "Lengths of " + InstrInfo->getName() +
":(TargetInfoFields, TargetInfoPositions) must be equal!";
for (unsigned i = 0, e = LI->getSize(); i != e; ++i)
emitShiftedValue(Inst.TheDef, dynamic_cast<StringInit*>(LI->getElement(i)),
dynamic_cast<IntInit*>(Shift->getElement(i)), OS);
OS << ", ";
// Emit the implicit uses and defs lists...
std::vector<Record*> UseList = Inst.TheDef->getValueAsListOfDefs("Uses");
if (UseList.empty())
OS << "NULL, ";
else
OS << "ImplicitList" << EmittedLists[UseList] << ", ";
std::vector<Record*> DefList = Inst.TheDef->getValueAsListOfDefs("Defs");
if (DefList.empty())
OS << "NULL, ";
else
OS << "ImplicitList" << EmittedLists[DefList] << ", ";
// Emit the operand info.
std::vector<std::string> OperandInfo = GetOperandInfo(Inst);
if (OperandInfo.empty())
OS << "0";
else
OS << "OperandInfo" << OpInfo.find(OperandInfo)->second;
OS << " }, // Inst #" << Num << " = " << Inst.TheDef->getName() << "\n";
}
void InstrInfoEmitter::emitShiftedValue(Record *R, StringInit *Val,
IntInit *ShiftInt, std::ostream &OS) {
if (Val == 0 || ShiftInt == 0)
throw std::string("Illegal value or shift amount in TargetInfo*!");
RecordVal *RV = R->getValue(Val->getValue());
int Shift = ShiftInt->getValue();
if (RV == 0 || RV->getValue() == 0) {
// This isn't an error if this is a builtin instruction.
if (R->getName() != "PHI" &&
R->getName() != "INLINEASM" &&
R->getName() != "LABEL" &&
R->getName() != "EXTRACT_SUBREG" &&
R->getName() != "INSERT_SUBREG")
throw R->getName() + " doesn't have a field named '" +
Val->getValue() + "'!";
return;
}
Init *Value = RV->getValue();
if (BitInit *BI = dynamic_cast<BitInit*>(Value)) {
if (BI->getValue()) OS << "|(1<<" << Shift << ")";
return;
} else if (BitsInit *BI = dynamic_cast<BitsInit*>(Value)) {
// Convert the Bits to an integer to print...
Init *I = BI->convertInitializerTo(new IntRecTy());
if (I)
if (IntInit *II = dynamic_cast<IntInit*>(I)) {
if (II->getValue()) {
if (Shift)
OS << "|(" << II->getValue() << "<<" << Shift << ")";
else
OS << "|" << II->getValue();
}
return;
}
} else if (IntInit *II = dynamic_cast<IntInit*>(Value)) {
if (II->getValue()) {
if (Shift)
OS << "|(" << II->getValue() << "<<" << Shift << ")";
else
OS << II->getValue();
}
return;
}
std::cerr << "Unhandled initializer: " << *Val << "\n";
throw "In record '" + R->getName() + "' for TSFlag emission.";
}