lib/Target/PIC16/PIC16TargetObjectFile.cpp - llvm - Git at Google

 //===-- PIC16TargetObjectFile.cpp - PIC16 object files --------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "PIC16TargetObjectFile.h"
 #include "MCSectionPIC16.h"
 #include "PIC16ISelLowering.h"
 #include "PIC16TargetMachine.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Module.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;


 MCSectionPIC16 *MCSectionPIC16::Create(const StringRef &Name,
                                        SectionKind K, MCContext &Ctx) {
   return new (Ctx) MCSectionPIC16(Name, K);
 }


 void MCSectionPIC16::PrintSwitchToSection(const TargetAsmInfo &TAI,
                                           raw_ostream &OS) const {
   OS << getName() << '\n';
 }


 PIC16TargetObjectFile::PIC16TargetObjectFile()
   : ExternalVarDecls(0), ExternalVarDefs(0) {
 }

 const MCSectionPIC16 *PIC16TargetObjectFile::
 getPIC16Section(const char *Name, SectionKind Kind) const {
   MCSectionPIC16 *&Entry = SectionsByName[Name];
   if (Entry)
     return Entry;

   return Entry = MCSectionPIC16::Create(Name, Kind, getContext());
 }


 void PIC16TargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &tm){
   TargetLoweringObjectFile::Initialize(Ctx, tm);
   TM = &tm;

   BSSSection = getPIC16Section("udata.# UDATA", SectionKind::getBSS());
   ReadOnlySection = getPIC16Section("romdata.# ROMDATA",
                                     SectionKind::getReadOnly());
   DataSection = getPIC16Section("idata.# IDATA", SectionKind::getDataRel());

   // Need because otherwise a .text symbol is emitted by DwarfWriter
   // in BeginModule, and gpasm cribbs for that .text symbol.
   TextSection = getPIC16Section("", SectionKind::getText());

   ROSections.push_back(new PIC16Section((MCSectionPIC16*)ReadOnlySection));

   // FIXME: I don't know what the classification of these sections really is.
   ExternalVarDecls = new PIC16Section(getPIC16Section("ExternalVarDecls",
                                       SectionKind::getMetadata()));
   ExternalVarDefs = new PIC16Section(getPIC16Section("ExternalVarDefs",
                                       SectionKind::getMetadata()));
 }

 const MCSection *PIC16TargetObjectFile::
 getSectionForFunction(const std::string &FnName) const {
   std::string T = PAN::getCodeSectionName(FnName);
   return getPIC16Section(T.c_str(), SectionKind::getText());
 }


 const MCSection *PIC16TargetObjectFile::
 getSectionForFunctionFrame(const std::string &FnName) const {
   std::string T = PAN::getFrameSectionName(FnName);
   return getPIC16Section(T.c_str(), SectionKind::getDataRel());
 }

 const MCSection *
 PIC16TargetObjectFile::getBSSSectionForGlobal(const GlobalVariable *GV) const {
   assert(GV->hasInitializer() && "This global doesn't need space");
   Constant *C = GV->getInitializer();
   assert(C->isNullValue() && "Unitialized globals has non-zero initializer");

   // Find how much space this global needs.
   const TargetData *TD = TM->getTargetData();
   const Type *Ty = C->getType();
   unsigned ValSize = TD->getTypeAllocSize(Ty);

   // Go through all BSS Sections and assign this variable
   // to the first available section having enough space.
   PIC16Section *FoundBSS = NULL;
   for (unsigned i = 0; i < BSSSections.size(); i++) {
     if (DataBankSize - BSSSections[i]->Size >= ValSize) {
       FoundBSS = BSSSections[i];
       break;
     }
   }

   // No BSS section spacious enough was found. Crate a new one.
   if (!FoundBSS) {
     std::string name = PAN::getUdataSectionName(BSSSections.size());
     const MCSectionPIC16 *NewSection
       = getPIC16Section(name.c_str(), /*FIXME*/ SectionKind::getMetadata());

     FoundBSS = new PIC16Section(NewSection);

     // Add this newly created BSS section to the list of BSSSections.
     BSSSections.push_back(FoundBSS);
   }

   // Insert the GV into this BSS.
   FoundBSS->Items.push_back(GV);
   FoundBSS->Size += ValSize;
   return FoundBSS->S_;
 }

 const MCSection *
 PIC16TargetObjectFile::getIDATASectionForGlobal(const GlobalVariable *GV) const{
   assert(GV->hasInitializer() && "This global doesn't need space");
   Constant *C = GV->getInitializer();
   assert(!C->isNullValue() && "initialized globals has zero initializer");
   assert(GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE &&
          "can split initialized RAM data only");

   // Find how much space this global needs.
   const TargetData *TD = TM->getTargetData();
   const Type *Ty = C->getType();
   unsigned ValSize = TD->getTypeAllocSize(Ty);

   // Go through all IDATA Sections and assign this variable
   // to the first available section having enough space.
   PIC16Section *FoundIDATA = NULL;
   for (unsigned i = 0; i < IDATASections.size(); i++) {
     if (DataBankSize - IDATASections[i]->Size >= ValSize) {
       FoundIDATA = IDATASections[i];
       break;
     }
   }

   // No IDATA section spacious enough was found. Crate a new one.
   if (!FoundIDATA) {
     std::string name = PAN::getIdataSectionName(IDATASections.size());
     const MCSectionPIC16 *NewSection =
       getPIC16Section(name.c_str(), /*FIXME*/ SectionKind::getMetadata());

     FoundIDATA = new PIC16Section(NewSection);

     // Add this newly created IDATA section to the list of IDATASections.
     IDATASections.push_back(FoundIDATA);
   }

   // Insert the GV into this IDATA.
   FoundIDATA->Items.push_back(GV);
   FoundIDATA->Size += ValSize;
   return FoundIDATA->S_;
 }

 // Get the section for an automatic variable of a function.
 // For PIC16 they are globals only with mangled names.
 const MCSection *
 PIC16TargetObjectFile::getSectionForAuto(const GlobalVariable *GV) const {

   const std::string name = PAN::getSectionNameForSym(GV->getName());

   // Go through all Auto Sections and assign this variable
   // to the appropriate section.
   PIC16Section *FoundAutoSec = NULL;
   for (unsigned i = 0; i < AutosSections.size(); i++) {
     if (AutosSections[i]->S_->getName() == name) {
       FoundAutoSec = AutosSections[i];
       break;
     }
   }

   // No Auto section was found. Crate a new one.
   if (!FoundAutoSec) {
     const MCSectionPIC16 *NewSection =
       getPIC16Section(name.c_str(), /*FIXME*/ SectionKind::getMetadata());

     FoundAutoSec = new PIC16Section(NewSection);

     // Add this newly created autos section to the list of AutosSections.
     AutosSections.push_back(FoundAutoSec);
   }

   // Insert the auto into this section.
   FoundAutoSec->Items.push_back(GV);

   return FoundAutoSec->S_;
 }


 // Override default implementation to put the true globals into
 // multiple data sections if required.
 const MCSection *
 PIC16TargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV1,
                                               SectionKind Kind,
                                               Mangler *Mang,
                                               const TargetMachine &TM) const {
   // We select the section based on the initializer here, so it really
   // has to be a GlobalVariable.
   const GlobalVariable *GV = dyn_cast<GlobalVariable>(GV1);
   if (!GV)
     return TargetLoweringObjectFile::SelectSectionForGlobal(GV1, Kind, Mang,TM);

   // Record External Var Decls.
   if (GV->isDeclaration()) {
     ExternalVarDecls->Items.push_back(GV);
     return ExternalVarDecls->S_;
   }

   assert(GV->hasInitializer() && "A def without initializer?");

   // First, if this is an automatic variable for a function, get the section
   // name for it and return.
   std::string name = GV->getName();
   if (PAN::isLocalName(name))
     return getSectionForAuto(GV);

   // Record Exteranl Var Defs.
   if (GV->hasExternalLinkage() || GV->hasCommonLinkage())
     ExternalVarDefs->Items.push_back(GV);

   // See if this is an uninitialized global.
   const Constant *C = GV->getInitializer();
   if (C->isNullValue())
     return getBSSSectionForGlobal(GV);

   // If this is initialized data in RAM. Put it in the correct IDATA section.
   if (GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE)
     return getIDATASectionForGlobal(GV);

   // This is initialized data in rom, put it in the readonly section.
   if (GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE)
     return getROSectionForGlobal(GV);

   // Else let the default implementation take care of it.
   return TargetLoweringObjectFile::SelectSectionForGlobal(GV, Kind, Mang,TM);
 }

 PIC16TargetObjectFile::~PIC16TargetObjectFile() {
   for (unsigned i = 0; i < BSSSections.size(); i++)
     delete BSSSections[i];
   for (unsigned i = 0; i < IDATASections.size(); i++)
     delete IDATASections[i];
   for (unsigned i = 0; i < AutosSections.size(); i++)
     delete AutosSections[i];
   for (unsigned i = 0; i < ROSections.size(); i++)
     delete ROSections[i];
   delete ExternalVarDecls;
   delete ExternalVarDefs;
 }


 /// getSpecialCasedSectionGlobals - Allow the target to completely override
 /// section assignment of a global.
 const MCSection *PIC16TargetObjectFile::
 getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
                          Mangler *Mang, const TargetMachine &TM) const {
   assert(GV->hasSection());

   if (const GlobalVariable *GVar = cast<GlobalVariable>(GV)) {
     std::string SectName = GVar->getSection();
     // If address for a variable is specified, get the address and create
     // section.
     std::string AddrStr = "Address=";
     if (SectName.compare(0, AddrStr.length(), AddrStr) == 0) {
       std::string SectAddr = SectName.substr(AddrStr.length());
       return CreateSectionForGlobal(GVar, Mang, SectAddr);
     }

     // Create the section specified with section attribute.
     return CreateSectionForGlobal(GVar, Mang);
   }

   return getPIC16Section(GV->getSection().c_str(), Kind);
 }

 // Create a new section for global variable. If Addr is given then create
 // section at that address else create by name.
 const MCSection *
 PIC16TargetObjectFile::CreateSectionForGlobal(const GlobalVariable *GV,
                                               Mangler *Mang,
                                               const std::string &Addr) const {
   // See if this is an uninitialized global.
   const Constant *C = GV->getInitializer();
   if (C->isNullValue())
     return CreateBSSSectionForGlobal(GV, Addr);

   // If this is initialized data in RAM. Put it in the correct IDATA section.
   if (GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE)
     return CreateIDATASectionForGlobal(GV, Addr);

   // This is initialized data in rom, put it in the readonly section.
   if (GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE)
     return CreateROSectionForGlobal(GV, Addr);

   // Else let the default implementation take care of it.
   return TargetLoweringObjectFile::SectionForGlobal(GV, Mang, *TM);
 }

 // Create uninitialized section for a variable.
 const MCSection *
 PIC16TargetObjectFile::CreateBSSSectionForGlobal(const GlobalVariable *GV,
                                                  std::string Addr) const {
   assert(GV->hasInitializer() && "This global doesn't need space");
   assert(GV->getInitializer()->isNullValue() &&
          "Unitialized global has non-zero initializer");
   std::string Name;
   // If address is given then create a section at that address else create a
   // section by section name specified in GV.
   PIC16Section *FoundBSS = NULL;
   if (Addr.empty()) {
     Name = GV->getSection() + " UDATA";
     for (unsigned i = 0; i < BSSSections.size(); i++) {
       if (BSSSections[i]->S_->getName() == Name) {
         FoundBSS = BSSSections[i];
         break;
       }
     }
   } else {
     std::string Prefix = GV->getNameStr() + "." + Addr + ".";
     Name = PAN::getUdataSectionName(BSSSections.size(), Prefix) + " " + Addr;
   }

   PIC16Section *NewBSS = FoundBSS;
   if (NewBSS == NULL) {
     const MCSectionPIC16 *NewSection =
       getPIC16Section(Name.c_str(), SectionKind::getBSS());
     NewBSS = new PIC16Section(NewSection);
     BSSSections.push_back(NewBSS);
   }

   // Insert the GV into this BSS.
   NewBSS->Items.push_back(GV);

   // We do not want to put any  GV without explicit section into this section
   // so set its size to DatabankSize.
   NewBSS->Size = DataBankSize;
   return NewBSS->S_;
 }

 // Get rom section for a variable. Currently there can be only one rom section
 // unless a variable explicitly requests a section.
 const MCSection *
 PIC16TargetObjectFile::getROSectionForGlobal(const GlobalVariable *GV) const {
   ROSections[0]->Items.push_back(GV);
   return ROSections[0]->S_;
 }

 // Create initialized data section for a variable.
 const MCSection *
 PIC16TargetObjectFile::CreateIDATASectionForGlobal(const GlobalVariable *GV,
                                                    std::string Addr) const {
   assert(GV->hasInitializer() && "This global doesn't need space");
   assert(!GV->getInitializer()->isNullValue() &&
          "initialized global has zero initializer");
   assert(GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE &&
          "can be used for initialized RAM data only");

   std::string Name;
   // If address is given then create a section at that address else create a
   // section by section name specified in GV.
   PIC16Section *FoundIDATASec = NULL;
   if (Addr.empty()) {
     Name = GV->getSection() + " IDATA";
     for (unsigned i = 0; i < IDATASections.size(); i++) {
       if (IDATASections[i]->S_->getName() == Name) {
         FoundIDATASec = IDATASections[i];
         break;
       }
     }
   } else {
     std::string Prefix = GV->getNameStr() + "." + Addr + ".";
     Name = PAN::getIdataSectionName(IDATASections.size(), Prefix) + " " + Addr;
   }

   PIC16Section *NewIDATASec = FoundIDATASec;
   if (NewIDATASec == NULL) {
     const MCSectionPIC16 *NewSection =
       getPIC16Section(Name.c_str(), /* FIXME */SectionKind::getMetadata());
     NewIDATASec = new PIC16Section(NewSection);
     IDATASections.push_back(NewIDATASec);
   }
   // Insert the GV into this IDATA Section.
   NewIDATASec->Items.push_back(GV);
   // We do not want to put any  GV without explicit section into this section
   // so set its size to DatabankSize.
   NewIDATASec->Size = DataBankSize;
   return NewIDATASec->S_;
 }

 // Create a section in rom for a variable.
 const MCSection *
 PIC16TargetObjectFile::CreateROSectionForGlobal(const GlobalVariable *GV,
                                                 std::string Addr) const {
   assert(GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE &&
          "can be used for ROM data only");

   std::string Name;
   // If address is given then create a section at that address else create a
   // section by section name specified in GV.
   PIC16Section *FoundROSec = NULL;
   if (Addr.empty()) {
     Name = GV->getSection() + " ROMDATA";
     for (unsigned i = 1; i < ROSections.size(); i++) {
       if (ROSections[i]->S_->getName() == Name) {
         FoundROSec = ROSections[i];
         break;
       }
     }
   } else {
     std::string Prefix = GV->getNameStr() + "." + Addr + ".";
     Name = PAN::getRomdataSectionName(ROSections.size(), Prefix) + " " + Addr;
   }

   PIC16Section *NewRomSec = FoundROSec;
   if (NewRomSec == NULL) {
     const MCSectionPIC16 *NewSection =
       getPIC16Section(Name.c_str(), SectionKind::getReadOnly());
     NewRomSec = new PIC16Section(NewSection);
     ROSections.push_back(NewRomSec);
   }

   // Insert the GV into this ROM Section.
   NewRomSec->Items.push_back(GV);
   return NewRomSec->S_;
 }
	//===-- PIC16TargetObjectFile.cpp - PIC16 object files --------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "PIC16TargetObjectFile.h"
	#include "MCSectionPIC16.h"
	#include "PIC16ISelLowering.h"
	#include "PIC16TargetMachine.h"
	#include "llvm/DerivedTypes.h"
	#include "llvm/Module.h"
	#include "llvm/MC/MCSection.h"
	#include "llvm/MC/MCContext.h"
	#include "llvm/Support/raw_ostream.h"
	using namespace llvm;


	MCSectionPIC16 *MCSectionPIC16::Create(const StringRef &Name,
	SectionKind K, MCContext &Ctx) {
	return new (Ctx) MCSectionPIC16(Name, K);
	}


	void MCSectionPIC16::PrintSwitchToSection(const TargetAsmInfo &TAI,
	raw_ostream &OS) const {
	OS << getName() << '\n';
	}




	PIC16TargetObjectFile::PIC16TargetObjectFile()
	: ExternalVarDecls(0), ExternalVarDefs(0) {
	}

	const MCSectionPIC16 *PIC16TargetObjectFile::
	getPIC16Section(const char *Name, SectionKind Kind) const {
	MCSectionPIC16 *&Entry = SectionsByName[Name];
	if (Entry)
	return Entry;

	return Entry = MCSectionPIC16::Create(Name, Kind, getContext());
	}


	void PIC16TargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &tm){
	TargetLoweringObjectFile::Initialize(Ctx, tm);
	TM = &tm;

	BSSSection = getPIC16Section("udata.# UDATA", SectionKind::getBSS());
	ReadOnlySection = getPIC16Section("romdata.# ROMDATA",
	SectionKind::getReadOnly());
	DataSection = getPIC16Section("idata.# IDATA", SectionKind::getDataRel());

	// Need because otherwise a .text symbol is emitted by DwarfWriter
	// in BeginModule, and gpasm cribbs for that .text symbol.
	TextSection = getPIC16Section("", SectionKind::getText());

	ROSections.push_back(new PIC16Section((MCSectionPIC16*)ReadOnlySection));

	// FIXME: I don't know what the classification of these sections really is.
	ExternalVarDecls = new PIC16Section(getPIC16Section("ExternalVarDecls",
	SectionKind::getMetadata()));
	ExternalVarDefs = new PIC16Section(getPIC16Section("ExternalVarDefs",
	SectionKind::getMetadata()));
	}

	const MCSection *PIC16TargetObjectFile::
	getSectionForFunction(const std::string &FnName) const {
	std::string T = PAN::getCodeSectionName(FnName);
	return getPIC16Section(T.c_str(), SectionKind::getText());
	}


	const MCSection *PIC16TargetObjectFile::
	getSectionForFunctionFrame(const std::string &FnName) const {
	std::string T = PAN::getFrameSectionName(FnName);
	return getPIC16Section(T.c_str(), SectionKind::getDataRel());
	}

	const MCSection *
	PIC16TargetObjectFile::getBSSSectionForGlobal(const GlobalVariable *GV) const {
	assert(GV->hasInitializer() && "This global doesn't need space");
	Constant *C = GV->getInitializer();
	assert(C->isNullValue() && "Unitialized globals has non-zero initializer");

	// Find how much space this global needs.
	const TargetData *TD = TM->getTargetData();
	const Type *Ty = C->getType();
	unsigned ValSize = TD->getTypeAllocSize(Ty);

	// Go through all BSS Sections and assign this variable
	// to the first available section having enough space.
	PIC16Section *FoundBSS = NULL;
	for (unsigned i = 0; i < BSSSections.size(); i++) {
	if (DataBankSize - BSSSections[i]->Size >= ValSize) {
	FoundBSS = BSSSections[i];
	break;
	}
	}

	// No BSS section spacious enough was found. Crate a new one.
	if (!FoundBSS) {
	std::string name = PAN::getUdataSectionName(BSSSections.size());
	const MCSectionPIC16 *NewSection
	= getPIC16Section(name.c_str(), /FIXME/ SectionKind::getMetadata());

	FoundBSS = new PIC16Section(NewSection);

	// Add this newly created BSS section to the list of BSSSections.
	BSSSections.push_back(FoundBSS);
	}

	// Insert the GV into this BSS.
	FoundBSS->Items.push_back(GV);
	FoundBSS->Size += ValSize;
	return FoundBSS->S_;
	}

	const MCSection *
	PIC16TargetObjectFile::getIDATASectionForGlobal(const GlobalVariable *GV) const{
	assert(GV->hasInitializer() && "This global doesn't need space");
	Constant *C = GV->getInitializer();
	assert(!C->isNullValue() && "initialized globals has zero initializer");
	assert(GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE &&
	"can split initialized RAM data only");

	// Find how much space this global needs.
	const TargetData *TD = TM->getTargetData();
	const Type *Ty = C->getType();
	unsigned ValSize = TD->getTypeAllocSize(Ty);

	// Go through all IDATA Sections and assign this variable
	// to the first available section having enough space.
	PIC16Section *FoundIDATA = NULL;
	for (unsigned i = 0; i < IDATASections.size(); i++) {
	if (DataBankSize - IDATASections[i]->Size >= ValSize) {
	FoundIDATA = IDATASections[i];
	break;
	}
	}

	// No IDATA section spacious enough was found. Crate a new one.
	if (!FoundIDATA) {
	std::string name = PAN::getIdataSectionName(IDATASections.size());
	const MCSectionPIC16 *NewSection =
	getPIC16Section(name.c_str(), /FIXME/ SectionKind::getMetadata());

	FoundIDATA = new PIC16Section(NewSection);

	// Add this newly created IDATA section to the list of IDATASections.
	IDATASections.push_back(FoundIDATA);
	}

	// Insert the GV into this IDATA.
	FoundIDATA->Items.push_back(GV);
	FoundIDATA->Size += ValSize;
	return FoundIDATA->S_;
	}

	// Get the section for an automatic variable of a function.
	// For PIC16 they are globals only with mangled names.
	const MCSection *
	PIC16TargetObjectFile::getSectionForAuto(const GlobalVariable *GV) const {

	const std::string name = PAN::getSectionNameForSym(GV->getName());

	// Go through all Auto Sections and assign this variable
	// to the appropriate section.
	PIC16Section *FoundAutoSec = NULL;
	for (unsigned i = 0; i < AutosSections.size(); i++) {
	if (AutosSections[i]->S_->getName() == name) {
	FoundAutoSec = AutosSections[i];
	break;
	}
	}

	// No Auto section was found. Crate a new one.
	if (!FoundAutoSec) {
	const MCSectionPIC16 *NewSection =
	getPIC16Section(name.c_str(), /FIXME/ SectionKind::getMetadata());

	FoundAutoSec = new PIC16Section(NewSection);

	// Add this newly created autos section to the list of AutosSections.
	AutosSections.push_back(FoundAutoSec);
	}

	// Insert the auto into this section.
	FoundAutoSec->Items.push_back(GV);

	return FoundAutoSec->S_;
	}


	// Override default implementation to put the true globals into
	// multiple data sections if required.
	const MCSection *
	PIC16TargetObjectFile::SelectSectionForGlobal(const GlobalValue *GV1,
	SectionKind Kind,
	Mangler *Mang,
	const TargetMachine &TM) const {
	// We select the section based on the initializer here, so it really
	// has to be a GlobalVariable.
	const GlobalVariable *GV = dyn_cast<GlobalVariable>(GV1);
	if (!GV)
	return TargetLoweringObjectFile::SelectSectionForGlobal(GV1, Kind, Mang,TM);

	// Record External Var Decls.
	if (GV->isDeclaration()) {
	ExternalVarDecls->Items.push_back(GV);
	return ExternalVarDecls->S_;
	}

	assert(GV->hasInitializer() && "A def without initializer?");

	// First, if this is an automatic variable for a function, get the section
	// name for it and return.
	std::string name = GV->getName();
	if (PAN::isLocalName(name))
	return getSectionForAuto(GV);

	// Record Exteranl Var Defs.
	if (GV->hasExternalLinkage() \|\| GV->hasCommonLinkage())
	ExternalVarDefs->Items.push_back(GV);

	// See if this is an uninitialized global.
	const Constant *C = GV->getInitializer();
	if (C->isNullValue())
	return getBSSSectionForGlobal(GV);

	// If this is initialized data in RAM. Put it in the correct IDATA section.
	if (GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE)
	return getIDATASectionForGlobal(GV);

	// This is initialized data in rom, put it in the readonly section.
	if (GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE)
	return getROSectionForGlobal(GV);

	// Else let the default implementation take care of it.
	return TargetLoweringObjectFile::SelectSectionForGlobal(GV, Kind, Mang,TM);
	}

	PIC16TargetObjectFile::~PIC16TargetObjectFile() {
	for (unsigned i = 0; i < BSSSections.size(); i++)
	delete BSSSections[i];
	for (unsigned i = 0; i < IDATASections.size(); i++)
	delete IDATASections[i];
	for (unsigned i = 0; i < AutosSections.size(); i++)
	delete AutosSections[i];
	for (unsigned i = 0; i < ROSections.size(); i++)
	delete ROSections[i];
	delete ExternalVarDecls;
	delete ExternalVarDefs;
	}


	/// getSpecialCasedSectionGlobals - Allow the target to completely override
	/// section assignment of a global.
	const MCSection *PIC16TargetObjectFile::
	getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
	Mangler *Mang, const TargetMachine &TM) const {
	assert(GV->hasSection());

	if (const GlobalVariable *GVar = cast<GlobalVariable>(GV)) {
	std::string SectName = GVar->getSection();
	// If address for a variable is specified, get the address and create
	// section.
	std::string AddrStr = "Address=";
	if (SectName.compare(0, AddrStr.length(), AddrStr) == 0) {
	std::string SectAddr = SectName.substr(AddrStr.length());
	return CreateSectionForGlobal(GVar, Mang, SectAddr);
	}

	// Create the section specified with section attribute.
	return CreateSectionForGlobal(GVar, Mang);
	}

	return getPIC16Section(GV->getSection().c_str(), Kind);
	}

	// Create a new section for global variable. If Addr is given then create
	// section at that address else create by name.
	const MCSection *
	PIC16TargetObjectFile::CreateSectionForGlobal(const GlobalVariable *GV,
	Mangler *Mang,
	const std::string &Addr) const {
	// See if this is an uninitialized global.
	const Constant *C = GV->getInitializer();
	if (C->isNullValue())
	return CreateBSSSectionForGlobal(GV, Addr);

	// If this is initialized data in RAM. Put it in the correct IDATA section.
	if (GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE)
	return CreateIDATASectionForGlobal(GV, Addr);

	// This is initialized data in rom, put it in the readonly section.
	if (GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE)
	return CreateROSectionForGlobal(GV, Addr);

	// Else let the default implementation take care of it.
	return TargetLoweringObjectFile::SectionForGlobal(GV, Mang, *TM);
	}

	// Create uninitialized section for a variable.
	const MCSection *
	PIC16TargetObjectFile::CreateBSSSectionForGlobal(const GlobalVariable *GV,
	std::string Addr) const {
	assert(GV->hasInitializer() && "This global doesn't need space");
	assert(GV->getInitializer()->isNullValue() &&
	"Unitialized global has non-zero initializer");
	std::string Name;
	// If address is given then create a section at that address else create a
	// section by section name specified in GV.
	PIC16Section *FoundBSS = NULL;
	if (Addr.empty()) {
	Name = GV->getSection() + " UDATA";
	for (unsigned i = 0; i < BSSSections.size(); i++) {
	if (BSSSections[i]->S_->getName() == Name) {
	FoundBSS = BSSSections[i];
	break;
	}
	}
	} else {
	std::string Prefix = GV->getNameStr() + "." + Addr + ".";
	Name = PAN::getUdataSectionName(BSSSections.size(), Prefix) + " " + Addr;
	}

	PIC16Section *NewBSS = FoundBSS;
	if (NewBSS == NULL) {
	const MCSectionPIC16 *NewSection =
	getPIC16Section(Name.c_str(), SectionKind::getBSS());
	NewBSS = new PIC16Section(NewSection);
	BSSSections.push_back(NewBSS);
	}

	// Insert the GV into this BSS.
	NewBSS->Items.push_back(GV);

	// We do not want to put any GV without explicit section into this section
	// so set its size to DatabankSize.
	NewBSS->Size = DataBankSize;
	return NewBSS->S_;
	}

	// Get rom section for a variable. Currently there can be only one rom section
	// unless a variable explicitly requests a section.
	const MCSection *
	PIC16TargetObjectFile::getROSectionForGlobal(const GlobalVariable *GV) const {
	ROSections[0]->Items.push_back(GV);
	return ROSections[0]->S_;
	}

	// Create initialized data section for a variable.
	const MCSection *
	PIC16TargetObjectFile::CreateIDATASectionForGlobal(const GlobalVariable *GV,
	std::string Addr) const {
	assert(GV->hasInitializer() && "This global doesn't need space");
	assert(!GV->getInitializer()->isNullValue() &&
	"initialized global has zero initializer");
	assert(GV->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE &&
	"can be used for initialized RAM data only");

	std::string Name;
	// If address is given then create a section at that address else create a
	// section by section name specified in GV.
	PIC16Section *FoundIDATASec = NULL;
	if (Addr.empty()) {
	Name = GV->getSection() + " IDATA";
	for (unsigned i = 0; i < IDATASections.size(); i++) {
	if (IDATASections[i]->S_->getName() == Name) {
	FoundIDATASec = IDATASections[i];
	break;
	}
	}
	} else {
	std::string Prefix = GV->getNameStr() + "." + Addr + ".";
	Name = PAN::getIdataSectionName(IDATASections.size(), Prefix) + " " + Addr;
	}

	PIC16Section *NewIDATASec = FoundIDATASec;
	if (NewIDATASec == NULL) {
	const MCSectionPIC16 *NewSection =
	getPIC16Section(Name.c_str(), /* FIXME */SectionKind::getMetadata());
	NewIDATASec = new PIC16Section(NewSection);
	IDATASections.push_back(NewIDATASec);
	}
	// Insert the GV into this IDATA Section.
	NewIDATASec->Items.push_back(GV);
	// We do not want to put any GV without explicit section into this section
	// so set its size to DatabankSize.
	NewIDATASec->Size = DataBankSize;
	return NewIDATASec->S_;
	}

	// Create a section in rom for a variable.
	const MCSection *
	PIC16TargetObjectFile::CreateROSectionForGlobal(const GlobalVariable *GV,
	std::string Addr) const {
	assert(GV->getType()->getAddressSpace() == PIC16ISD::ROM_SPACE &&
	"can be used for ROM data only");

	std::string Name;
	// If address is given then create a section at that address else create a
	// section by section name specified in GV.
	PIC16Section *FoundROSec = NULL;
	if (Addr.empty()) {
	Name = GV->getSection() + " ROMDATA";
	for (unsigned i = 1; i < ROSections.size(); i++) {
	if (ROSections[i]->S_->getName() == Name) {
	FoundROSec = ROSections[i];
	break;
	}
	}
	} else {
	std::string Prefix = GV->getNameStr() + "." + Addr + ".";
	Name = PAN::getRomdataSectionName(ROSections.size(), Prefix) + " " + Addr;
	}

	PIC16Section *NewRomSec = FoundROSec;
	if (NewRomSec == NULL) {
	const MCSectionPIC16 *NewSection =
	getPIC16Section(Name.c_str(), SectionKind::getReadOnly());
	NewRomSec = new PIC16Section(NewSection);
	ROSections.push_back(NewRomSec);
	}

	// Insert the GV into this ROM Section.
	NewRomSec->Items.push_back(GV);
	return NewRomSec->S_;
	}