lib/Target/PIC16/PIC16TargetAsmInfo.cpp

//===-- PIC16TargetAsmInfo.cpp - PIC16 asm properties ---------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source 
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of the PIC16TargetAsmInfo properties.
//
//===----------------------------------------------------------------------===//

#include "PIC16TargetAsmInfo.h"
#include "PIC16TargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/GlobalVariable.h"
#include "llvm/DerivedTypes.h"

using namespace llvm;

PIC16TargetAsmInfo::
PIC16TargetAsmInfo(const PIC16TargetMachine &TM) 
  : TargetAsmInfo(TM) {
  CommentString = ";";
  GlobalPrefix = PAN::getTagName(PAN::PREFIX_SYMBOL);
  GlobalDirective = "\tglobal\t";
  ExternDirective = "\textern\t";

  Data8bitsDirective = " db ";
  Data16bitsDirective = " dw ";
  Data32bitsDirective = " dl ";
  Data64bitsDirective = NULL;
  RomData8bitsDirective = " dw ";
  RomData16bitsDirective = " rom_di ";
  RomData32bitsDirective = " rom_dl ";
  ZeroDirective = NULL;
  AsciiDirective = " dt ";
  AscizDirective = NULL;
  BSSSection_  = getNamedSection("udata.# UDATA",
                              SectionFlags::Writeable | SectionFlags::BSS);
  ReadOnlySection = getNamedSection("romdata.# ROMDATA", SectionFlags::None);
  DataSection = getNamedSection("idata.# IDATA", SectionFlags::Writeable);
  SwitchToSectionDirective = "";
  // Need because otherwise a .text symbol is emitted by DwarfWriter
  // in BeginModule, and gpasm cribbs for that .text symbol.
  TextSection = getUnnamedSection("", SectionFlags::Code);
  PIC16Section *ROSection = new PIC16Section(getReadOnlySection());
  ROSections.push_back(ROSection);
  ExternalVarDecls = new PIC16Section(getNamedSection("ExternalVarDecls"));
  ExternalVarDefs = new PIC16Section(getNamedSection("ExternalVarDefs"));
  // Set it to false because we weed to generate c file name and not bc file
  // name.
  HasSingleParameterDotFile = false;
}

const char *PIC16TargetAsmInfo::getRomDirective(unsigned Size) const {
  switch (Size) {
  case  8: return RomData8bitsDirective;
  case 16: return RomData16bitsDirective;
  case 32: return RomData32bitsDirective;
  default: return NULL;
  }
}


const char *PIC16TargetAsmInfo::
getDataASDirective(unsigned Size, unsigned AS) const {
  if (AS == PIC16ISD::ROM_SPACE)
    return getRomDirective(Size);
  return NULL;
}

const Section *
PIC16TargetAsmInfo::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 Section *NewSection = getNamedSection (name.c_str());

    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;

  // We can't do this here because GV is const .
  // const std::string SName = FoundBSS->S_->getName();
  // GV->setSection(SName);

  return FoundBSS->S_;
} 

const Section *
PIC16TargetAsmInfo::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 Section *NewSection = getNamedSection (name.c_str());

    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;

  // We can't do this here because GV is const .
  // GV->setSection(FoundIDATA->S->getName());

  return FoundIDATA->S_;
} 

// Get the section for an automatic variable of a function.
// For PIC16 they are globals only with mangled names.
const Section *
PIC16TargetAsmInfo::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 Section *NewSection = getNamedSection (name.c_str());

    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 Section*
PIC16TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV1) 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 TargetAsmInfo::SelectSectionForGlobal(GV1);

  // Record Exteranl 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.
  const 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 TargetAsmInfo::SelectSectionForGlobal(GV);
}

PIC16TargetAsmInfo::~PIC16TargetAsmInfo() {
  
  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;
}

// Override the default implementation. Create PIC16sections for variables 
// which have a section name or address.
const Section* 
PIC16TargetAsmInfo::SectionForGlobal(const GlobalValue *GV) const {
  const Section* S;
  // If GV has a sectin name or section address create that section now.
  if (GV->hasSection()) {
    std::string SectName = GV->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());
      S = CreateSectionForGlobal(GV, SectAddr);
    }
    else {
      S = CreateSectionForGlobal(GV);
    } 
  } else {
    // Use section depending on the 'type' of variable
    S = SelectSectionForGlobal(GV);
  }
  return S;
}

// Create a new section for global variable. If Addr is given then create
// section at that address else create by name.
const Section *
PIC16TargetAsmInfo::CreateSectionForGlobal(const GlobalValue *GV1,
                                           std::string Addr) const {
  const GlobalVariable *GV = dyn_cast<GlobalVariable>(GV1);

  if (!GV)
    return TargetAsmInfo::SectionForGlobal(GV1);

  // 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 TargetAsmInfo::SectionForGlobal(GV);
}

// Create uninitialized section for a variable.
const Section *
PIC16TargetAsmInfo::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->getName() + "." + Addr + ".";
    Name = PAN::getUdataSectionName(BSSSections.size(), Prefix) + " " + Addr;
  }
  
  PIC16Section *NewBSS = FoundBSS;
  if (NewBSS == NULL) {
    const Section *NewSection = getNamedSection (Name.c_str());
    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 Section *
PIC16TargetAsmInfo::getROSectionForGlobal(const GlobalVariable *GV) const {
  ROSections[0]->Items.push_back(GV);
  return ROSections[0]->S_;
}

// Create initialized data section for a variable.
const Section *
PIC16TargetAsmInfo::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->getName() + "." + Addr + ".";
    Name = PAN::getIdataSectionName(IDATASections.size(), Prefix) + " " + Addr;
  }

  PIC16Section *NewIDATASec = FoundIDATASec;
  if (NewIDATASec == NULL) {
    const Section *NewSection = getNamedSection (Name.c_str());
    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 Section *
PIC16TargetAsmInfo::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->getName() + "." + Addr + ".";
    Name = PAN::getRomdataSectionName(ROSections.size(), Prefix) + " " + Addr;
  }

  PIC16Section *NewRomSec = FoundROSec;
  if (NewRomSec == NULL) {
    const Section *NewSection = getNamedSection (Name.c_str());
    NewRomSec = new PIC16Section(NewSection);
    ROSections.push_back(NewRomSec);
  }

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