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llvm-mirror/lib/Target/TargetData.cpp
Evan Cheng 8596afac45 Dead comment. 
llvm-svn: 33719
2007-01-31 21:31:25 +00:00

508 lines
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//===-- 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()) / 8;
if (BoolPrefAlignment == 0)
BoolPrefAlignment = BoolABIAlignment;
break;
case 'A':
AggMinPrefAlignment = atoi(getToken(token,":").c_str()) / 8;
break;
default:
break;
}
}
// Unless explicitly specified, the alignments for longs and doubles is
// capped by pointer size.
if (LongABIAlignment == 0)
LongABIAlignment = LongPrefAlignment = PointerMemSize;
if (DoubleABIAlignment == 0)
DoubleABIAlignment = DoublePrefAlignment = PointerMemSize;
}
TargetData::TargetData(const Module *M) {
init(M->getDataLayout());
}
/// Layouts - The lazy cache of structure layout information maintained by
/// TargetData.
///
static std::map<std::pair<const TargetData*,const StructType*>,
StructLayout> *Layouts = 0;
TargetData::~TargetData() {
if (Layouts) {
// Remove any layouts for this TD.
std::map<std::pair<const TargetData*,
const StructType*>, StructLayout>::iterator
I = Layouts->lower_bound(std::make_pair(this, (const StructType*)0));
while (I != Layouts->end() && I->first.first == this)
Layouts->erase(I++);
if (Layouts->empty()) {
delete Layouts;
Layouts = 0;
}
}
}
std::string TargetData::getStringRepresentation() const {
std::stringstream repr;
if (LittleEndian)
repr << "e";
else
repr << "E";
repr << "-p:" << (PointerMemSize * 8) << ":" << (PointerABIAlignment * 8);
repr << "-d:" << (DoubleABIAlignment * 8) << ":"
<< (DoublePrefAlignment * 8);
repr << "-f:" << (FloatABIAlignment * 8) << ":"
<< (FloatPrefAlignment * 8);
repr << "-l:" << (LongABIAlignment * 8) << ":"
<< (LongPrefAlignment * 8);
repr << "-i:" << (IntABIAlignment * 8) << ":"
<< (IntPrefAlignment * 8);
repr << "-s:" << (ShortABIAlignment * 8) << ":"
<< (ShortPrefAlignment * 8);
repr << "-b:" << (ByteABIAlignment * 8) << ":"
<< (BytePrefAlignment * 8);
repr << "-B:" << (BoolABIAlignment * 8) << ":"
<< (BoolPrefAlignment * 8);
repr << "-A:" << (AggMinPrefAlignment * 8);
return repr.str();
}
const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
if (Layouts == 0)
Layouts = new std::map<std::pair<const TargetData*,const StructType*>,
StructLayout>();
std::map<std::pair<const TargetData*,const StructType*>,
StructLayout>::iterator
I = Layouts->lower_bound(std::make_pair(this, Ty));
if (I != Layouts->end() && I->first.first == this && I->first.second == Ty)
return &I->second;
else {
return &Layouts->insert(I, std::make_pair(std::make_pair(this, Ty),
StructLayout(Ty, *this)))->second;
}
}
/// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
/// objects. If a TargetData object is alive when types are being refined and
/// removed, this method must be called whenever a StructType is removed to
/// avoid a dangling pointer in this cache.
void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
if (!Layouts) return; // No cache.
std::map<std::pair<const TargetData*,const StructType*>,
StructLayout>::iterator I = Layouts->find(std::make_pair(this, Ty));
if (I != Layouts->end())
Layouts->erase(I);
}
static inline void getTypeInfoABI(const Type *Ty, const TargetData *TD,
uint64_t &Size, unsigned char &Alignment) {
assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
switch (Ty->getTypeID()) {
case Type::IntegerTyID: {
unsigned BitWidth = cast<IntegerType>(Ty)->getBitWidth();
if (BitWidth <= 8) {
Size = 1; Alignment = TD->getByteABIAlignment();
} else if (BitWidth <= 16) {
Size = 2; Alignment = TD->getShortABIAlignment();
} else if (BitWidth <= 32) {
Size = 4; Alignment = TD->getIntABIAlignment();
} else if (BitWidth <= 64) {
Size = 8; Alignment = TD->getLongABIAlignment();
} else
assert(0 && "Integer types > 64 bits not supported.");
return;
}
case Type::VoidTyID: Size = 1; Alignment = TD->getByteABIAlignment(); return;
case Type::FloatTyID: Size = 4; Alignment = TD->getFloatABIAlignment(); return;
case Type::DoubleTyID: Size = 8; Alignment = TD->getDoubleABIAlignment(); return;
case Type::LabelTyID:
case Type::PointerTyID:
Size = TD->getPointerSize(); Alignment = TD->getPointerABIAlignment();
return;
case Type::ArrayTyID: {
const ArrayType *ATy = cast<ArrayType>(Ty);
getTypeInfoABI(ATy->getElementType(), TD, Size, Alignment);
unsigned AlignedSize = (Size + Alignment - 1)/Alignment*Alignment;
Size = AlignedSize*ATy->getNumElements();
return;
}
case Type::PackedTyID: {
const PackedType *PTy = cast<PackedType>(Ty);
getTypeInfoABI(PTy->getElementType(), TD, Size, Alignment);
unsigned AlignedSize = (Size + Alignment - 1)/Alignment*Alignment;
Size = AlignedSize*PTy->getNumElements();
// FIXME: The alignments of specific packed types are target dependent.
// For now, just set it to be equal to Size.
Alignment = Size;
return;
}
case Type::StructTyID: {
// Get the layout annotation... which is lazily created on demand.
const StructLayout *Layout = TD->getStructLayout(cast<StructType>(Ty));
Size = Layout->StructSize; Alignment = Layout->StructAlignment;
return;
}
default:
assert(0 && "Bad type for getTypeInfo!!!");
return;
}
}
static inline void getTypeInfoPref(const Type *Ty, const TargetData *TD,
uint64_t &Size, unsigned char &Alignment) {
assert(Ty->isSized() && "Cannot getTypeInfoPref() on a type that is unsized!");
switch (Ty->getTypeID()) {
case Type::IntegerTyID: {
unsigned BitWidth = cast<IntegerType>(Ty)->getBitWidth();
if (BitWidth <= 8) {
Size = 1; Alignment = TD->getBytePrefAlignment();
} else if (BitWidth <= 16) {
Size = 2; Alignment = TD->getShortPrefAlignment();
} else if (BitWidth <= 32) {
Size = 4; Alignment = TD->getIntPrefAlignment();
} else if (BitWidth <= 64) {
Size = 8; Alignment = TD->getLongPrefAlignment();
} else
assert(0 && "Integer types > 64 bits not supported.");
return;
}
case Type::VoidTyID:
Size = 1; Alignment = TD->getBytePrefAlignment();
return;
case Type::FloatTyID:
Size = 4; Alignment = TD->getFloatPrefAlignment();
return;
case Type::DoubleTyID:
Size = 8; Alignment = TD->getDoublePrefAlignment();
return;
case Type::LabelTyID:
case Type::PointerTyID:
Size = TD->getPointerSize(); Alignment = TD->getPointerPrefAlignment();
return;
case Type::ArrayTyID: {
const ArrayType *ATy = cast<ArrayType>(Ty);
getTypeInfoPref(ATy->getElementType(), TD, Size, Alignment);
unsigned AlignedSize = (Size + Alignment - 1)/Alignment*Alignment;
Size = AlignedSize*ATy->getNumElements();
return;
}
case Type::PackedTyID: {
const PackedType *PTy = cast<PackedType>(Ty);
getTypeInfoPref(PTy->getElementType(), TD, Size, Alignment);
unsigned AlignedSize = (Size + Alignment - 1)/Alignment*Alignment;
Size = AlignedSize*PTy->getNumElements();
// FIXME: The alignments of specific packed types are target dependent.
// For now, just set it to be equal to Size.
Alignment = Size;
return;
}
case Type::StructTyID: {
// Get the layout annotation... which is lazily created on demand;
// enforce minimum aggregate alignment.
const StructLayout *Layout = TD->getStructLayout(cast<StructType>(Ty));
Size = Layout->StructSize;
Alignment = std::max(Layout->StructAlignment,
(const unsigned int) TD->getAggMinPrefAlignment());
return;
}
default:
assert(0 && "Bad type for getTypeInfoPref!!!");
return;
}
}
uint64_t TargetData::getTypeSize(const Type *Ty) const {
uint64_t Size;
unsigned char Align;
getTypeInfoABI(Ty, this, Size, Align);
return Size;
}
uint64_t TargetData::getTypeSizeInBits(const Type *Ty) const {
if (Ty->isInteger())
return cast<IntegerType>(Ty)->getBitWidth();
uint64_t Size;
unsigned char Align;
getTypeInfoABI(Ty, this, Size, Align);
return Size * 8;
}
unsigned char TargetData::getTypeAlignmentABI(const Type *Ty) const {
uint64_t Size;
unsigned char Align;
getTypeInfoABI(Ty, this, Size, Align);
return Align;
}
unsigned char TargetData::getTypeAlignmentPref(const Type *Ty) const {
uint64_t Size;
unsigned char Align;
getTypeInfoPref(Ty, this, Size, Align);
return Align;
}
unsigned char TargetData::getPreferredTypeAlignmentShift(const Type *Ty) const {
unsigned Align = getTypeAlignmentPref(Ty);
assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
return Log2_32(Align);
}
/// getIntPtrType - Return an unsigned integer type that is the same size or
/// greater to the host pointer size.
const Type *TargetData::getIntPtrType() const {
switch (getPointerSize()) {
default: assert(0 && "Unknown pointer size!");
case 2: return Type::Int16Ty;
case 4: return Type::Int32Ty;
case 8: return Type::Int64Ty;
}
}
uint64_t TargetData::getIndexedOffset(const Type *ptrTy,
const std::vector<Value*> &Idx) const {
const Type *Ty = ptrTy;
assert(isa<PointerType>(Ty) && "Illegal argument for getIndexedOffset()");
uint64_t Result = 0;
generic_gep_type_iterator<std::vector<Value*>::const_iterator>
TI = gep_type_begin(ptrTy, Idx.begin(), Idx.end());
for (unsigned CurIDX = 0; CurIDX != Idx.size(); ++CurIDX, ++TI) {
if (const StructType *STy = dyn_cast<StructType>(*TI)) {
assert(Idx[CurIDX]->getType() == Type::Int32Ty && "Illegal struct idx");
unsigned FieldNo = cast<ConstantInt>(Idx[CurIDX])->getZExtValue();
// Get structure layout information...
const StructLayout *Layout = getStructLayout(STy);
// Add in the offset, as calculated by the structure layout info...
assert(FieldNo < Layout->MemberOffsets.size() &&"FieldNo out of range!");
Result += Layout->MemberOffsets[FieldNo];
// Update Ty to refer to current element
Ty = STy->getElementType(FieldNo);
} else {
// Update Ty to refer to current element
Ty = cast<SequentialType>(Ty)->getElementType();
// Get the array index and the size of each array element.
int64_t arrayIdx = cast<ConstantInt>(Idx[CurIDX])->getSExtValue();
Result += arrayIdx * (int64_t)getTypeSize(Ty);
}
}
return Result;
}
/// getPreferredAlignmentLog - Return the preferred alignment of the
/// specified global, returned in log form. This includes an explicitly
/// requested alignment (if the global has one).
unsigned TargetData::getPreferredAlignmentLog(const GlobalVariable *GV) const {
const Type *ElemType = GV->getType()->getElementType();
unsigned Alignment = getPreferredTypeAlignmentShift(ElemType);
if (GV->getAlignment() > (1U << Alignment))
Alignment = Log2_32(GV->getAlignment());
if (GV->hasInitializer()) {
if (Alignment < 4) {
// If the global is not external, see if it is large. If so, give it a
// larger alignment.
if (getTypeSize(ElemType) > 128)
Alignment = 4; // 16-byte alignment.
}
}
return Alignment;
}
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