path: root/lib/Target/TargetData.cpp

//===-- TargetData.cpp - Data size & alignment routines --------------------==//
//
//                     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.
//
//===----------------------------------------------------------------------===//
//
// This file defines target properties related to datatype size/offset/alignment
// information.
//
// This structure should be created once, filled in if the defaults are not
// correct and then passed around by const&.  None of the members functions
// require modification to the object.
//
//===----------------------------------------------------------------------===//

#include "llvm/Target/TargetData.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Constants.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/ADT/StringExtras.h"
#include <algorithm>
#include <cstdlib>
#include <sstream>
using namespace llvm;

// Handle the Pass registration stuff necessary to use TargetData's.
namespace {
  // Register the default SparcV9 implementation...
  RegisterPass<TargetData> X("targetdata", "Target Data Layout");
}

static inline void getTypeInfoABI(const Type *Ty, const TargetData *TD,
                                  uint64_t &Size, unsigned char &Alignment);

static inline void getTypeInfoPref(const Type *Ty, const TargetData *TD,
                                   uint64_t &Size, unsigned char &Alignment);

//===----------------------------------------------------------------------===//
// Support for StructLayout
//===----------------------------------------------------------------------===//

StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
  StructAlignment = 0;
  StructSize = 0;

  // Loop over each of the elements, placing them in memory...
  for (StructType::element_iterator TI = ST->element_begin(),
         TE = ST->element_end(); TI != TE; ++TI) {
    const Type *Ty = *TI;
    unsigned char A;
    unsigned TyAlign;
    uint64_t TySize;
    getTypeInfoABI(Ty, &TD, TySize, A);
    TyAlign = ST->isPacked() ? 1 : A;

    // Add padding if necessary to make the data element aligned properly...
    if (StructSize % TyAlign != 0)
      StructSize = (StructSize/TyAlign + 1) * TyAlign;   // Add padding...

    // Keep track of maximum alignment constraint
    StructAlignment = std::max(TyAlign, StructAlignment);

    MemberOffsets.push_back(StructSize);
    StructSize += TySize;                 // Consume space for this data item
  }

  // Empty structures have alignment of 1 byte.
  if (StructAlignment == 0) StructAlignment = 1;

  // Add padding to the end of the struct so that it could be put in an array
  // and all array elements would be aligned correctly.
  if (StructSize % StructAlignment != 0)
    StructSize = (StructSize/StructAlignment + 1) * StructAlignment;
}


/// getElementContainingOffset - Given a valid offset into the structure,
/// return the structure index that contains it.
unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
  std::vector<uint64_t>::const_iterator SI =
    std::upper_bound(MemberOffsets.begin(), MemberOffsets.end(), Offset);
  assert(SI != MemberOffsets.begin() && "Offset not in structure type!");
  --SI;
  assert(*SI <= Offset && "upper_bound didn't work");
  assert((SI == MemberOffsets.begin() || *(SI-1) < Offset) &&
         (SI+1 == MemberOffsets.end() || *(SI+1) > Offset) &&
         "Upper bound didn't work!");
  return SI-MemberOffsets.begin();
}

//===----------------------------------------------------------------------===//
//                       TargetData Class Implementation
//===----------------------------------------------------------------------===//

void TargetData::init(const std::string &TargetDescription) {
  std::string temp = TargetDescription;
  
  LittleEndian = false;
  PointerMemSize = 8;
  PointerABIAlignment   = 8;
  DoubleABIAlignment = 0;
  FloatABIAlignment = 4;
  LongABIAlignment   = 0;
  IntABIAlignment   = 4;
  ShortABIAlignment  = 2;
  ByteABIAlignment  = 1;
  BoolABIAlignment   = 1;
  BoolPrefAlignment = BoolABIAlignment;
  BytePrefAlignment = ByteABIAlignment;
  ShortPrefAlignment = ShortABIAlignment;
  IntPrefAlignment = IntABIAlignment;
  LongPrefAlignment = 8;
  FloatPrefAlignment = FloatABIAlignment;
  DoublePrefAlignment = 8;
  PointerPrefAlignment = PointerABIAlignment;
  AggMinPrefAlignment = 0;
  
  while (!temp.empty()) {
    std::string token = getToken(temp, "-");
    
    char signal = getToken(token, ":")[0];
    
    switch(signal) {
    case 'E':
      LittleEndian = false;
      break;
    case 'e':
      LittleEndian = true;
      break;
    case 'p':
      PointerMemSize = atoi(getToken(token,":").c_str()) / 8;
      PointerABIAlignment = atoi(getToken(token,":").c_str()) / 8;
      PointerPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (PointerPrefAlignment == 0)
        PointerPrefAlignment = PointerABIAlignment;
      break;
    case 'd':
      DoubleABIAlignment = atoi(getToken(token,":").c_str()) / 8;
      DoublePrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (DoublePrefAlignment == 0)
        DoublePrefAlignment = DoubleABIAlignment;
      break;
    case 'f':
      FloatABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      FloatPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (FloatPrefAlignment == 0)
        FloatPrefAlignment = FloatABIAlignment;
      break;
    case 'l':
      LongABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      LongPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (LongPrefAlignment == 0)
        LongPrefAlignment = LongABIAlignment;
      break;
    case 'i':
      IntABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      IntPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (IntPrefAlignment == 0)
        IntPrefAlignment = IntABIAlignment;
      break;
    case 's':
      ShortABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      ShortPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (ShortPrefAlignment == 0)
        ShortPrefAlignment = ShortABIAlignment;
      break;
    case 'b':
      ByteABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      BytePrefAlignment = atoi(getToken(token,":").c_str()) / 8;
      if (BytePrefAlignment == 0)
        BytePrefAlignment = ByteABIAlignment;
      break;
    case 'B':
      BoolABIAlignment = atoi(getToken(token, ":").c_str()) / 8;
      BoolPrefAlignment = atoi(getToken(token,":").c_str