//===-- 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. It uses lazy annotations to cache information about how
-// structure types are laid out and used.
+// 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
//===----------------------------------------------------------------------===//
#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 getTypeInfo(const Type *Ty, const TargetData *TD,
- unsigned &Size, unsigned char &Alignment);
+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 Annotation
+// Support for StructLayout
//===----------------------------------------------------------------------===//
-StructLayout::StructLayout(const StructType *ST, const TargetData &TD)
- : Annotation(TD.getStructLayoutAID()) {
+StructLayout::StructLayout(const StructType *ST, const TargetData &TD) {
StructAlignment = 0;
StructSize = 0;
// Loop over each of the elements, placing them in memory...
- for (StructType::ElementTypes::const_iterator
- TI = ST->getElementTypes().begin(),
- TE = ST->getElementTypes().end(); TI != TE; ++TI) {
+ for (StructType::element_iterator TI = ST->element_begin(),
+ TE = ST->element_end(); TI != TE; ++TI) {
const Type *Ty = *TI;
unsigned char A;
- unsigned TySize, TyAlign;
- getTypeInfo(Ty, &TD, TySize, A); TyAlign = A;
+ unsigned TyAlign;
+ uint64_t TySize;
+ getTypeInfoABI(Ty, &TD, TySize, A);
+ TyAlign = ST->isPacked() ? 1 : A;
- // Add padding if neccesary to make the data element aligned properly...
+ // Add padding if necessary to make the data element aligned properly...
if (StructSize % TyAlign != 0)
StructSize = (StructSize/TyAlign + 1) * TyAlign; // Add padding...
StructAlignment = std::max(TyAlign, StructAlignment);
MemberOffsets.push_back(StructSize);
- StructSize += TySize; // Consume space for this data item...
+ 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;
-
- if (StructSize == 0) {
- StructSize = 1; // Empty struct is 1 byte
- StructAlignment = 1;
- }
}
-Annotation *TargetData::TypeAnFactory(AnnotationID AID, const Annotable *T,
- void *D) {
- const TargetData &TD = *(const TargetData*)D;
- assert(AID == TD.AID && "Target data annotation ID mismatch!");
- const Type *Ty = cast<Type>((const Value *)T);
- assert(isa<StructType>(Ty) &&
- "Can only create StructLayout annotation on structs!");
- return new StructLayout(cast<StructType>(Ty), TD);
+
+/// 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
//===----------------------------------------------------------------------===//
-TargetData::TargetData(const std::string &TargetName, unsigned char PtrSize = 8,
- unsigned char PtrAl = 8, unsigned char DoubleAl = 8,
- unsigned char FloatAl = 4, unsigned char LongAl = 8,
- unsigned char IntAl = 4, unsigned char ShortAl = 2,
- unsigned char ByteAl = 1)
- : AID(AnnotationManager::getID("TargetData::" + TargetName)) {
- AnnotationManager::registerAnnotationFactory(AID, TypeAnFactory, this);
+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;
+}
- PointerSize = PtrSize;
- PointerAlignment = PtrAl;
- DoubleAlignment = DoubleAl;
- FloatAlignment = FloatAl;
- LongAlignment = LongAl;
- IntAlignment = IntAl;
- ShortAlignment = ShortAl;
- ByteAlignment = ByteAl;
+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() {
- AnnotationManager::registerAnnotationFactory(AID, 0); // Deregister factory
+ 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;
+ }
+ }
}
-static inline void getTypeInfo(const Type *Ty, const TargetData *TD,
- unsigned &Size, unsigned char &Alignment) {
+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->getPrimitiveID()) {
- case Type::VoidTyID:
- case Type::BoolTyID:
- case Type::UByteTyID:
- case Type::SByteTyID: Size = 1; Alignment = TD->getByteAlignment(); return;
- case Type::UShortTyID:
- case Type::ShortTyID: Size = 2; Alignment = TD->getShortAlignment(); return;
- case Type::UIntTyID:
- case Type::IntTyID: Size = 4; Alignment = TD->getIntAlignment(); return;
- case Type::ULongTyID:
- case Type::LongTyID: Size = 8; Alignment = TD->getLongAlignment(); return;
- case Type::FloatTyID: Size = 4; Alignment = TD->getFloatAlignment(); return;
- case Type::DoubleTyID: Size = 8; Alignment = TD->getDoubleAlignment(); return;
+ 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 {
+ Size = ((BitWidth + 7) / 8) & ~1;
+ Alignment = TD->getLongABIAlignment();
+ }
+ 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->getPointerAlignment();
+ Size = TD->getPointerSize(); Alignment = TD->getPointerABIAlignment();
return;
case Type::ArrayTyID: {
- const ArrayType *ATy = (const ArrayType *)Ty;
- getTypeInfo(ATy->getElementType(), TD, Size, Alignment);
- Size *= ATy->getNumElements();
+ 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((const StructType*)Ty);
+ const StructLayout *Layout = TD->getStructLayout(cast<StructType>(Ty));
Size = Layout->StructSize; Alignment = Layout->StructAlignment;
return;
}
-
- case Type::TypeTyID:
+
default:
assert(0 && "Bad type for getTypeInfo!!!");
return;
}
}
-unsigned TargetData::getTypeSize(const Type *Ty) const {
- unsigned Size; unsigned char Align;
- getTypeInfo(Ty, this, Size, Align);
+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;
}
-unsigned char TargetData::getTypeAlignment(const Type *Ty) const {
- unsigned Size; unsigned char Align;
- getTypeInfo(Ty, this, Size, Align);
+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 TargetData::getIndexedOffset(const Type *Ty,
- const std::vector<Value*> &Idx) const {
- unsigned Result = 0;
+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;
- for (unsigned CurIDX = 0, E = Idx.size(); CurIDX != E; ++CurIDX) {
- if (const StructType *STy = dyn_cast<StructType>(Ty)) {
- assert(Idx[CurIDX]->getType() == Type::UByteTy && "Illegal struct idx");
- unsigned FieldNo = cast<ConstantUInt>(Idx[CurIDX])->getValue();
+ 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!");
+ assert(FieldNo < Layout->MemberOffsets.size() &&"FieldNo out of range!");
Result += Layout->MemberOffsets[FieldNo];
-
- // Update Ty to refer to current element
- Ty = STy->getElementTypes()[FieldNo];
-
- } else if (const SequentialType *STy = dyn_cast<SequentialType>(Ty)) {
- assert(Idx[CurIDX]->getType() == Type::UIntTy &&"Illegal sequential idx");
- assert(isa<ConstantUInt>(Idx[CurIDX]) &&
- "getIndexedOffset cannot compute offset of non-constant index!");
- unsigned IndexNo = cast<ConstantUInt>(Idx[CurIDX])->getValue();
- Ty = STy->getElementType();
-
- Result += IndexNo*getTypeSize(Ty);
+ // Update Ty to refer to current element
+ Ty = STy->getElementType(FieldNo);
} else {
- assert(0 && "Indexing type that is not struct, array, or pointer?");
- return 0; // Load directly through ptr
+ // 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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