llvm-6502/lib/CodeGen/TargetMachine/TargetMachine.cpp

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// $Id$
//***************************************************************************
// File:
// TargetMachine.cpp
//
// Purpose:
//
// History:
// 7/12/01 - Vikram Adve - Created
//**************************************************************************/
//*************************** User Include Files ***************************/
#include "llvm/CodeGen/TargetMachine.h"
#include "llvm/DerivedTypes.h"
//************************ Exported Constants ******************************/
// External object describing the machine instructions
// Initialized only when the TargetMachine class is created
// and reset when that class is destroyed.
//
const MachineInstrDescriptor* TargetInstrDescriptors = NULL;
resourceId_t MachineResource::nextId = 0;
//************************* Forward Declarations **************************/
static cycles_t ComputeMinGap (const InstrRUsage& fromRU,
const InstrRUsage& toRU);
static bool RUConflict (const vector<resourceId_t>& fromRVec,
const vector<resourceId_t>& fromRVec);
//************************ Class Implementations **************************/
//---------------------------------------------------------------------------
// class TargetMachine
//
// Purpose:
// Machine description.
//
//---------------------------------------------------------------------------
// function TargetMachine::findOptimalStorageSize
//
// Purpose:
// This default implementation assumes that all sub-word data items use
// space equal to optSizeForSubWordData, and all other primitive data
// items use space according to the type.
//
unsigned int TargetMachine::findOptimalStorageSize(const Type* ty) const {
switch(ty->getPrimitiveID()) {
case Type::BoolTyID:
case Type::UByteTyID:
case Type::SByteTyID:
case Type::UShortTyID:
case Type::ShortTyID:
return optSizeForSubWordData;
default:
return DataLayout.getTypeSize(ty);
}
}
//---------------------------------------------------------------------------
// class MachineInstructionInfo
// Interface to description of machine instructions
//---------------------------------------------------------------------------
/*ctor*/
MachineInstrInfo::MachineInstrInfo(const MachineInstrDescriptor* _desc,
unsigned int _descSize,
unsigned int _numRealOpCodes)
: desc(_desc), descSize(_descSize), numRealOpCodes(_numRealOpCodes)
{
assert(TargetInstrDescriptors == NULL && desc != NULL);
TargetInstrDescriptors = desc; // initialize global variable
}
/*dtor*/
MachineInstrInfo::~MachineInstrInfo()
{
TargetInstrDescriptors = NULL; // reset global variable
}
bool
MachineInstrInfo::constantFitsInImmedField(MachineOpCode opCode,
int64_t intValue) const
{
// First, check if opCode has an immed field.
bool isSignExtended;
uint64_t maxImmedValue = this->maxImmedConstant(opCode, isSignExtended);
if (maxImmedValue != 0)
{
// Now check if the constant fits
if (intValue <= (int64_t) maxImmedValue &&
intValue >= -((int64_t) maxImmedValue+1))
return true;
}
return false;
}
//---------------------------------------------------------------------------
// class MachineSchedInfo
// Interface to machine description for instruction scheduling
//---------------------------------------------------------------------------
/*ctor*/
MachineSchedInfo::MachineSchedInfo(int _numSchedClasses,
const MachineInstrInfo* _mii,
const InstrClassRUsage* _classRUsages,
const InstrRUsageDelta* _usageDeltas,
const InstrIssueDelta* _issueDeltas,
unsigned int _numUsageDeltas,
unsigned int _numIssueDeltas)
: numSchedClasses(_numSchedClasses),
mii(_mii),
classRUsages(_classRUsages),
usageDeltas(_usageDeltas),
issueDeltas(_issueDeltas),
numUsageDeltas(_numUsageDeltas),
numIssueDeltas(_numIssueDeltas)
{
}
void
MachineSchedInfo::initializeResources()
{
assert(MAX_NUM_SLOTS >= (int) getMaxNumIssueTotal()
&& "Insufficient slots for static data! Increase MAX_NUM_SLOTS");
// First, compute common resource usage info for each class because
// most instructions will probably behave the same as their class.
// Cannot allocate a vector of InstrRUsage so new each one.
//
vector<InstrRUsage> instrRUForClasses;
instrRUForClasses.resize(numSchedClasses);
for (InstrSchedClass sc=0; sc < numSchedClasses; sc++)
{
// instrRUForClasses.push_back(new InstrRUsage);
instrRUForClasses[sc].setMaxSlots(getMaxNumIssueTotal());
instrRUForClasses[sc] = classRUsages[sc];
}
computeInstrResources(instrRUForClasses);
computeIssueGaps(instrRUForClasses);
}
void
MachineSchedInfo::computeInstrResources(const vector<InstrRUsage>& instrRUForClasses)
{
int numOpCodes = mii->getNumRealOpCodes();
instrRUsages.resize(numOpCodes);
// First get the resource usage information from the class resource usages.
for (MachineOpCode op=0; op < numOpCodes; op++)
{
InstrSchedClass sc = getSchedClass(op);
assert(sc >= 0 && sc < numSchedClasses);
instrRUsages[op] = instrRUForClasses[sc];
}
// Now, modify the resource usages as specified in the deltas.
for (unsigned i=0; i < numUsageDeltas; i++)
{
MachineOpCode op = usageDeltas[i].opCode;
assert(op < numOpCodes);
instrRUsages[op].addUsageDelta(usageDeltas[i]);
}
// Then modify the issue restrictions as specified in the deltas.
for (unsigned i=0; i < numIssueDeltas; i++)
{
MachineOpCode op = issueDeltas[i].opCode;
assert(op < numOpCodes);
instrRUsages[issueDeltas[i].opCode].addIssueDelta(issueDeltas[i]);
}
}
void
MachineSchedInfo::computeIssueGaps(const vector<InstrRUsage>& instrRUForClasses)
{
int numOpCodes = mii->getNumRealOpCodes();
instrRUsages.resize(numOpCodes);
assert(numOpCodes < (1 << MAX_OPCODE_SIZE) - 1
&& "numOpCodes invalid for implementation of class OpCodePair!");
// First, compute issue gaps between pairs of classes based on common
// resources usages for each class, because most instruction pairs will
// usually behave the same as their class.
//
int classPairGaps[numSchedClasses][numSchedClasses];
for (InstrSchedClass fromSC=0; fromSC < numSchedClasses; fromSC++)
for (InstrSchedClass toSC=0; toSC < numSchedClasses; toSC++)
{
int classPairGap = ComputeMinGap(instrRUForClasses[fromSC],
instrRUForClasses[toSC]);
classPairGaps[fromSC][toSC] = classPairGap;
}
// Now, for each pair of instructions, use the class pair gap if both
// instructions have identical resource usage as their respective classes.
// If not, recompute the gap for the pair from scratch.
longestIssueConflict = 0;
for (MachineOpCode fromOp=0; fromOp < numOpCodes; fromOp++)
for (MachineOpCode toOp=0; toOp < numOpCodes; toOp++)
{
int instrPairGap =
(instrRUsages[fromOp].sameAsClass && instrRUsages[toOp].sameAsClass)
? classPairGaps[getSchedClass(fromOp)][getSchedClass(toOp)]
: ComputeMinGap(instrRUsages[fromOp], instrRUsages[toOp]);
if (instrPairGap > 0)
{
issueGaps[OpCodePair(fromOp,toOp)] = instrPairGap;
conflictLists[fromOp].push_back(toOp);
longestIssueConflict = max(longestIssueConflict, instrPairGap);
}
}
}
// Check if fromRVec and toRVec have *any* common entries.
// Assume the vectors are sorted in increasing order.
// Algorithm copied from function set_intersection() for sorted ranges (stl_algo.h).
inline static bool
RUConflict(const vector<resourceId_t>& fromRVec,
const vector<resourceId_t>& toRVec)
{
bool commonElementFound = false;
unsigned fN = fromRVec.size(), tN = toRVec.size();
unsigned fi = 0, ti = 0;
while (fi < fN && ti < tN)
if (fromRVec[fi] < toRVec[ti])
++fi;
else if (toRVec[ti] < fromRVec[fi])
++ti;
else
{
commonElementFound = true;
break;
}
return commonElementFound;
}
static cycles_t
ComputeMinGap(const InstrRUsage& fromRU, const InstrRUsage& toRU)
{
cycles_t minGap = 0;
if (fromRU.numBubbles > 0)
minGap = fromRU.numBubbles;
if (minGap < fromRU.numCycles)
{
// only need to check from cycle `minGap' onwards
for (cycles_t gap=minGap; gap <= fromRU.numCycles-1; gap++)
{
// check if instr. #2 can start executing `gap' cycles after #1
// by checking for resource conflicts in each overlapping cycle
cycles_t numOverlap = min(fromRU.numCycles - gap, toRU.numCycles);
for (cycles_t c = 0; c <= numOverlap-1; c++)
if (RUConflict(fromRU.resourcesByCycle[gap + c],
toRU.resourcesByCycle[c]))
{// conflict found so minGap must be more than `gap'
minGap = gap+1;
break;
}
}
}
return minGap;
}
//---------------------------------------------------------------------------