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