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//===-- llvm/Target/TargetData.h - Data size & alignment info ---*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file defines target properties related to datatype size/offset/alignment
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// information. It uses lazy annotations to cache information about how
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// structure types are laid out and used.
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// This structure should be created once, filled in if the defaults are not
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// correct and then passed around by const&. None of the members functions
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// require modification to the object.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TARGET_TARGETDATA_H
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#define LLVM_TARGET_TARGETDATA_H
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#include "llvm/Pass.h"
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#include "llvm/ADT/SmallVector.h"
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/// Enum used to categorize the alignment types stored by TargetAlignElem
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INTEGER_ALIGN = 'i', ///< Integer type alignment
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VECTOR_ALIGN = 'v', ///< Vector type alignment
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FLOAT_ALIGN = 'f', ///< Floating point type alignment
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AGGREGATE_ALIGN = 'a', ///< Aggregate alignment
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STACK_ALIGN = 's' ///< Stack objects alignment
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/// Target alignment element.
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/// Stores the alignment data associated with a given alignment type (pointer,
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/// integer, vector, float) and type bit width.
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/// @note The unusual order of elements in the structure attempts to reduce
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/// padding and make the structure slightly more cache friendly.
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struct TargetAlignElem {
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AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum)
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unsigned char ABIAlign; //< ABI alignment for this type/bitw
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unsigned char PrefAlign; //< Pref. alignment for this type/bitw
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uint32_t TypeBitWidth; //< Type bit width
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static TargetAlignElem get(AlignTypeEnum align_type, unsigned char abi_align,
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unsigned char pref_align, uint32_t bit_width);
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/// Equality predicate
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bool operator==(const TargetAlignElem &rhs) const;
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class TargetData : public ImmutablePass {
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bool LittleEndian; ///< Defaults to false
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unsigned char PointerMemSize; ///< Pointer size in bytes
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unsigned char PointerABIAlign; ///< Pointer ABI alignment
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unsigned char PointerPrefAlign; ///< Pointer preferred alignment
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SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
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/// Alignments- Where the primitive type alignment data is stored.
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/// @note Could support multiple size pointer alignments, e.g., 32-bit
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/// pointers vs. 64-bit pointers by extending TargetAlignment, but for now,
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SmallVector<TargetAlignElem, 16> Alignments;
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/// InvalidAlignmentElem - This member is a signal that a requested alignment
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/// type and bit width were not found in the SmallVector.
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static const TargetAlignElem InvalidAlignmentElem;
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// The StructType -> StructLayout map.
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mutable void *LayoutMap;
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//! Set/initialize target alignments
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void setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
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unsigned char pref_align, uint32_t bit_width);
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unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
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bool ABIAlign, const Type *Ty) const;
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//! Internal helper method that returns requested alignment for type.
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unsigned char getAlignment(const Type *Ty, bool abi_or_pref) const;
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/// Valid alignment predicate.
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/// Predicate that tests a TargetAlignElem reference returned by get() against
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/// InvalidAlignmentElem.
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bool validAlignment(const TargetAlignElem &align) const {
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return &align != &InvalidAlignmentElem;
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/// @note This has to exist, because this is a pass, but it should never be
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/// Constructs a TargetData from a specification string. See init().
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explicit TargetData(StringRef TargetDescription)
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: ImmutablePass(&ID) {
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init(TargetDescription);
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/// Initialize target data from properties stored in the module.
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explicit TargetData(const Module *M);
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TargetData(const TargetData &TD) :
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LittleEndian(TD.isLittleEndian()),
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PointerMemSize(TD.PointerMemSize),
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PointerABIAlign(TD.PointerABIAlign),
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PointerPrefAlign(TD.PointerPrefAlign),
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LegalIntWidths(TD.LegalIntWidths),
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Alignments(TD.Alignments),
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~TargetData(); // Not virtual, do not subclass this class
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//! Parse a target data layout string and initialize TargetData alignments.
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void init(StringRef TargetDescription);
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/// Target endianness...
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bool isLittleEndian() const { return LittleEndian; }
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bool isBigEndian() const { return !LittleEndian; }
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/// getStringRepresentation - Return the string representation of the
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/// TargetData. This representation is in the same format accepted by the
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/// string constructor above.
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std::string getStringRepresentation() const;
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/// isLegalInteger - This function returns true if the specified type is
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/// known tobe a native integer type supported by the CPU. For example,
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/// i64 is not native on most 32-bit CPUs and i37 is not native on any known
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/// one. This returns false if the integer width is not legal.
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/// The width is specified in bits.
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bool isLegalInteger(unsigned Width) const {
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for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
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if (LegalIntWidths[i] == Width)
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bool isIllegalInteger(unsigned Width) const {
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return !isLegalInteger(Width);
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/// Target pointer alignment
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unsigned char getPointerABIAlignment() const { return PointerABIAlign; }
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/// Return target's alignment for stack-based pointers
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unsigned char getPointerPrefAlignment() const { return PointerPrefAlign; }
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/// Target pointer size
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unsigned char getPointerSize() const { return PointerMemSize; }
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/// Target pointer size, in bits
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unsigned char getPointerSizeInBits() const { return 8*PointerMemSize; }
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/// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
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/// ---- ---------- --------------- ---------------
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/// X86_FP80 80 80 96
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/// [*] The alloc size depends on the alignment, and thus on the target.
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/// These values are for x86-32 linux.
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/// getTypeSizeInBits - Return the number of bits necessary to hold the
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/// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
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uint64_t getTypeSizeInBits(const Type* Ty) const;
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/// getTypeStoreSize - Return the maximum number of bytes that may be
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/// overwritten by storing the specified type. For example, returns 5
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/// for i36 and 10 for x86_fp80.
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uint64_t getTypeStoreSize(const Type *Ty) const {
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return (getTypeSizeInBits(Ty)+7)/8;
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/// getTypeStoreSizeInBits - Return the maximum number of bits that may be
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/// overwritten by storing the specified type; always a multiple of 8. For
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/// example, returns 40 for i36 and 80 for x86_fp80.
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uint64_t getTypeStoreSizeInBits(const Type *Ty) const {
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return 8*getTypeStoreSize(Ty);
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/// getTypeAllocSize - Return the offset in bytes between successive objects
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/// of the specified type, including alignment padding. This is the amount
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/// that alloca reserves for this type. For example, returns 12 or 16 for
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/// x86_fp80, depending on alignment.
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uint64_t getTypeAllocSize(const Type* Ty) const {
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// Round up to the next alignment boundary.
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return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
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/// getTypeAllocSizeInBits - Return the offset in bits between successive
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/// objects of the specified type, including alignment padding; always a
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/// multiple of 8. This is the amount that alloca reserves for this type.
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/// For example, returns 96 or 128 for x86_fp80, depending on alignment.
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uint64_t getTypeAllocSizeInBits(const Type* Ty) const {
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return 8*getTypeAllocSize(Ty);
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/// getABITypeAlignment - Return the minimum ABI-required alignment for the
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unsigned char getABITypeAlignment(const Type *Ty) const;
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/// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
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/// an integer type of the specified bitwidth.
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unsigned char getABIIntegerTypeAlignment(unsigned BitWidth) const;
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/// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
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/// for the specified type when it is part of a call frame.
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unsigned char getCallFrameTypeAlignment(const Type *Ty) const;
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/// getPrefTypeAlignment - Return the preferred stack/global alignment for
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/// the specified type. This is always at least as good as the ABI alignment.
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unsigned char getPrefTypeAlignment(const Type *Ty) const;
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/// getPreferredTypeAlignmentShift - Return the preferred alignment for the
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/// specified type, returned as log2 of the value (a shift amount).
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unsigned char getPreferredTypeAlignmentShift(const Type *Ty) const;
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/// getIntPtrType - Return an unsigned integer type that is the same size or
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/// greater to the host pointer size.
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const IntegerType *getIntPtrType(LLVMContext &C) const;
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/// getIndexedOffset - return the offset from the beginning of the type for
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/// the specified indices. This is used to implement getelementptr.
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uint64_t getIndexedOffset(const Type *Ty,
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Value* const* Indices, unsigned NumIndices) const;
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/// getStructLayout - Return a StructLayout object, indicating the alignment
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/// of the struct, its size, and the offsets of its fields. Note that this
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/// information is lazily cached.
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const StructLayout *getStructLayout(const StructType *Ty) const;
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/// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
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/// objects. If a TargetData object is alive when types are being refined and
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/// removed, this method must be called whenever a StructType is removed to
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/// avoid a dangling pointer in this cache.
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void InvalidateStructLayoutInfo(const StructType *Ty) const;
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/// getPreferredAlignment - Return the preferred alignment of the specified
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/// global. This includes an explicitly requested alignment (if the global
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unsigned getPreferredAlignment(const GlobalVariable *GV) const;
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/// getPreferredAlignmentLog - Return the preferred alignment of the
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/// specified global, returned in log form. This includes an explicitly
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/// requested alignment (if the global has one).
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unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
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/// RoundUpAlignment - Round the specified value up to the next alignment
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/// boundary specified by Alignment. For example, 7 rounded up to an
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/// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
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/// is 8 because it is already aligned.
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template <typename UIntTy>
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static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
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assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
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return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
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static char ID; // Pass identification, replacement for typeid
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/// StructLayout - used to lazily calculate structure layout information for a
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/// target machine, based on the TargetData structure.
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unsigned StructAlignment;
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unsigned NumElements;
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uint64_t MemberOffsets[1]; // variable sized array!
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uint64_t getSizeInBytes() const {
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uint64_t getSizeInBits() const {
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unsigned getAlignment() const {
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return StructAlignment;
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/// getElementContainingOffset - Given a valid byte offset into the structure,
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/// return the structure index that contains it.
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unsigned getElementContainingOffset(uint64_t Offset) const;
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uint64_t getElementOffset(unsigned Idx) const {
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assert(Idx < NumElements && "Invalid element idx!");
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return MemberOffsets[Idx];
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uint64_t getElementOffsetInBits(unsigned Idx) const {
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return getElementOffset(Idx)*8;
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friend class TargetData; // Only TargetData can create this class
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StructLayout(const StructType *ST, const TargetData &TD);
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} // End llvm namespace