llvm-6502/lib/Target/TargetInstrInfo.cpp

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//===-- TargetInstrInfo.cpp - Target Instruction Information --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Constant.h"
#include "llvm/DerivedTypes.h"
namespace llvm {
// External object describing the machine instructions
// Initialized only when the TargetMachine class is created
// and reset when that class is destroyed.
//
const TargetInstrDescriptor* TargetInstrDescriptors = 0;
TargetInstrInfo::TargetInstrInfo(const TargetInstrDescriptor* Desc,
unsigned numOpcodes)
: desc(Desc), NumOpcodes(numOpcodes) {
// FIXME: TargetInstrDescriptors should not be global
assert(TargetInstrDescriptors == NULL && desc != NULL
&& "TargetMachine data structure corrupt; maybe you tried to create another TargetMachine? (only one may exist in a program)");
TargetInstrDescriptors = desc; // initialize global variable
}
TargetInstrInfo::~TargetInstrInfo() {
TargetInstrDescriptors = NULL; // reset global variable
}
bool TargetInstrInfo::constantFitsInImmedField(MachineOpCode opCode,
int64_t intValue) const {
// First, check if opCode has an immed field.
bool isSignExtended;
uint64_t maxImmedValue = maxImmedConstant(opCode, isSignExtended);
if (maxImmedValue != 0)
{
// NEED TO HANDLE UNSIGNED VALUES SINCE THEY MAY BECOME MUCH
// SMALLER AFTER CASTING TO SIGN-EXTENDED int, short, or char.
// See CreateUIntSetInstruction in SparcInstrInfo.cpp.
// Now check if the constant fits
if (intValue <= (int64_t) maxImmedValue &&
intValue >= -((int64_t) maxImmedValue+1))
return true;
}
return false;
}
} // End llvm namespace