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Diffstat (limited to 'lib/Target/TargetMachine.cpp')
-rw-r--r-- | lib/Target/TargetMachine.cpp | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp new file mode 100644 index 0000000000..a9e376e10a --- /dev/null +++ b/lib/Target/TargetMachine.cpp @@ -0,0 +1,279 @@ +//===-- TargetMachine.cpp - General Target Information ---------------------==// +// +// This file describes the general parts of a Target machine. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Target/Machine.h" +#include "llvm/DerivedTypes.h" + +// 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; + +static cycles_t ComputeMinGap (const InstrRUsage& fromRU, + const InstrRUsage& toRU); + +static bool RUConflict (const vector<resourceId_t>& fromRVec, + const vector<resourceId_t>& fromRVec); + +//--------------------------------------------------------------------------- +// 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; +} + +//--------------------------------------------------------------------------- |