llvm-6502/lib/CodeGen/TargetMachine/TargetMachine.cpp
Vikram S. Adve 44a853cc53 Added MachineInstrInfo class and moved instruction-related members there.
Added several fields to MachineInstrDescriptor (and renamed it from
MachineInstrInfo.  Latency fields are to support scheduling.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308 91177308-0d34-0410-b5e6-96231b3b80d8
2001-07-28 04:09:37 +00:00

174 lines
4.8 KiB
C++

// $Id$
//***************************************************************************
// 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;
//************************ Class Implementations **************************/
//---------------------------------------------------------------------------
// class TargetMachine
//
// Purpose:
// Machine description.
//
//---------------------------------------------------------------------------
// function TargetMachine::findOptimalStorageSize
//
// Purpose:
// Compute optimal storage size for a structure, based on
// the optimal member offsets.
// 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;
break;
case Type::UIntTyID: case Type::IntTyID:
return intSize;
break;
case Type::FloatTyID:
return floatSize;
break;
case Type::ULongTyID: case Type::LongTyID:
return longSize;
break;
case Type::DoubleTyID:
return doubleSize;
break;
case Type::PointerTyID:
case Type::LabelTyID: case Type::MethodTyID:
return pointerSize;
break;
case Type::ArrayTyID:
{
ArrayType* aty = (ArrayType*) ty;
assert(aty->getNumElements() >= 0 &&
"Attempting to compute size for unknown-size array");
return (unsigned) aty->getNumElements() *
this->findOptimalStorageSize(aty->getElementType());
break;
}
case Type::StructTyID:
{// This code should be invoked only from StructType::getStorageSize().
StructType* sty = (StructType*) ty;
unsigned lastMemberIdx = sty->getElementTypes().size() - 1;
unsigned lastMemberOffset = sty->getElementOffset(lastMemberIdx, *this);
unsigned storageSize = lastMemberOffset
+ this->findOptimalStorageSize(sty->getElementTypes()[lastMemberIdx]);
return storageSize;
break;
}
default:
assert(0 && "Unexpected type in `findOptimalStorageSize'");
return 0;
break;
}
}
// function TargetMachine::findOptimalMemberOffsets
//
// Purpose:
// Compute optimal offsets for the members of a structure.
// Returns a vector of unsigned ints, one per member.
// Caller is responsible for freeing the vector.
unsigned int*
TargetMachine::findOptimalMemberOffsets(const StructType* stype) const
{
int numMembers = stype->getElementTypes().size();
unsigned int* offsetVec = new unsigned int[numMembers];
unsigned int netOffset = 0;
for (int i = 0; i < numMembers; i++)
{
offsetVec[i] = netOffset;
const Type* memberType = stype->getElementTypes()[i];
netOffset += this->findOptimalStorageSize(memberType);
}
return offsetVec;
}
//---------------------------------------------------------------------------
// class MachineInstructionInfo
// Interface to description of machine instructions
//---------------------------------------------------------------------------
/*ctor*/
MachineInstrInfo::MachineInstrInfo(const MachineInstrDescriptor* _desc,
unsigned int _descSize)
: desc(_desc), descSize(_descSize)
{
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;
}
//---------------------------------------------------------------------------