1 //===-- llvm/Target/TargetData.h - Data size & alignment info ---*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines target properties related to datatype size/offset/alignment
11 // information. It uses lazy annotations to cache information about how
12 // structure types are laid out and used.
14 // This structure should be created once, filled in if the defaults are not
15 // correct and then passed around by const&. None of the members functions
16 // require modification to the object.
18 //===----------------------------------------------------------------------===//
20 #ifndef LLVM_TARGET_TARGETDATA_H
21 #define LLVM_TARGET_TARGETDATA_H
23 #include "llvm/Pass.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/Support/DataTypes.h"
39 /// Enum used to categorize the alignment types stored by TargetAlignElem
41 INTEGER_ALIGN = 'i', ///< Integer type alignment
42 VECTOR_ALIGN = 'v', ///< Vector type alignment
43 FLOAT_ALIGN = 'f', ///< Floating point type alignment
44 AGGREGATE_ALIGN = 'a', ///< Aggregate alignment
45 STACK_ALIGN = 's' ///< Stack objects alignment
47 /// Target alignment element.
49 /// Stores the alignment data associated with a given alignment type (pointer,
50 /// integer, vector, float) and type bit width.
52 /// @note The unusual order of elements in the structure attempts to reduce
53 /// padding and make the structure slightly more cache friendly.
54 struct TargetAlignElem {
55 AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum)
56 unsigned ABIAlign; //< ABI alignment for this type/bitw
57 unsigned PrefAlign; //< Pref. alignment for this type/bitw
58 uint32_t TypeBitWidth; //< Type bit width
61 static TargetAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
62 unsigned pref_align, uint32_t bit_width);
63 /// Equality predicate
64 bool operator==(const TargetAlignElem &rhs) const;
67 class TargetData : public ImmutablePass {
69 bool LittleEndian; ///< Defaults to false
70 unsigned PointerMemSize; ///< Pointer size in bytes
71 unsigned PointerABIAlign; ///< Pointer ABI alignment
72 unsigned PointerPrefAlign; ///< Pointer preferred alignment
74 SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
76 /// Alignments- Where the primitive type alignment data is stored.
79 /// @note Could support multiple size pointer alignments, e.g., 32-bit
80 /// pointers vs. 64-bit pointers by extending TargetAlignment, but for now,
82 SmallVector<TargetAlignElem, 16> Alignments;
84 /// InvalidAlignmentElem - This member is a signal that a requested alignment
85 /// type and bit width were not found in the SmallVector.
86 static const TargetAlignElem InvalidAlignmentElem;
88 // The StructType -> StructLayout map.
89 mutable void *LayoutMap;
91 //! Set/initialize target alignments
92 void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
93 unsigned pref_align, uint32_t bit_width);
94 unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
95 bool ABIAlign, Type *Ty) const;
96 //! Internal helper method that returns requested alignment for type.
97 unsigned getAlignment(Type *Ty, bool abi_or_pref) const;
99 /// Valid alignment predicate.
101 /// Predicate that tests a TargetAlignElem reference returned by get() against
102 /// InvalidAlignmentElem.
103 bool validAlignment(const TargetAlignElem &align) const {
104 return &align != &InvalidAlignmentElem;
110 /// @note This has to exist, because this is a pass, but it should never be
114 /// Constructs a TargetData from a specification string. See init().
115 explicit TargetData(StringRef TargetDescription)
116 : ImmutablePass(ID) {
117 init(TargetDescription);
120 /// Initialize target data from properties stored in the module.
121 explicit TargetData(const Module *M);
123 TargetData(const TargetData &TD) :
125 LittleEndian(TD.isLittleEndian()),
126 PointerMemSize(TD.PointerMemSize),
127 PointerABIAlign(TD.PointerABIAlign),
128 PointerPrefAlign(TD.PointerPrefAlign),
129 LegalIntWidths(TD.LegalIntWidths),
130 Alignments(TD.Alignments),
134 ~TargetData(); // Not virtual, do not subclass this class
136 //! Parse a target data layout string and initialize TargetData alignments.
137 void init(StringRef TargetDescription);
139 /// Target endianness...
140 bool isLittleEndian() const { return LittleEndian; }
141 bool isBigEndian() const { return !LittleEndian; }
143 /// getStringRepresentation - Return the string representation of the
144 /// TargetData. This representation is in the same format accepted by the
145 /// string constructor above.
146 std::string getStringRepresentation() const;
148 /// isLegalInteger - This function returns true if the specified type is
149 /// known to be a native integer type supported by the CPU. For example,
150 /// i64 is not native on most 32-bit CPUs and i37 is not native on any known
151 /// one. This returns false if the integer width is not legal.
153 /// The width is specified in bits.
155 bool isLegalInteger(unsigned Width) const {
156 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
157 if (LegalIntWidths[i] == Width)
162 bool isIllegalInteger(unsigned Width) const {
163 return !isLegalInteger(Width);
166 /// fitsInLegalInteger - This function returns true if the specified type fits
167 /// in a native integer type supported by the CPU. For example, if the CPU
168 /// only supports i32 as a native integer type, then i27 fits in a legal
169 // integer type but i45 does not.
170 bool fitsInLegalInteger(unsigned Width) const {
171 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
172 if (Width <= LegalIntWidths[i])
177 /// Target pointer alignment
178 unsigned getPointerABIAlignment() const { return PointerABIAlign; }
179 /// Return target's alignment for stack-based pointers
180 unsigned getPointerPrefAlignment() const { return PointerPrefAlign; }
181 /// Target pointer size
182 unsigned getPointerSize() const { return PointerMemSize; }
183 /// Target pointer size, in bits
184 unsigned getPointerSizeInBits() const { return 8*PointerMemSize; }
188 /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
189 /// ---- ---------- --------------- ---------------
198 /// X86_FP80 80 80 96
200 /// [*] The alloc size depends on the alignment, and thus on the target.
201 /// These values are for x86-32 linux.
203 /// getTypeSizeInBits - Return the number of bits necessary to hold the
204 /// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
205 uint64_t getTypeSizeInBits(Type* Ty) const;
207 /// getTypeStoreSize - Return the maximum number of bytes that may be
208 /// overwritten by storing the specified type. For example, returns 5
209 /// for i36 and 10 for x86_fp80.
210 uint64_t getTypeStoreSize(Type *Ty) const {
211 return (getTypeSizeInBits(Ty)+7)/8;
214 /// getTypeStoreSizeInBits - Return the maximum number of bits that may be
215 /// overwritten by storing the specified type; always a multiple of 8. For
216 /// example, returns 40 for i36 and 80 for x86_fp80.
217 uint64_t getTypeStoreSizeInBits(Type *Ty) const {
218 return 8*getTypeStoreSize(Ty);
221 /// getTypeAllocSize - Return the offset in bytes between successive objects
222 /// of the specified type, including alignment padding. This is the amount
223 /// that alloca reserves for this type. For example, returns 12 or 16 for
224 /// x86_fp80, depending on alignment.
225 uint64_t getTypeAllocSize(Type* Ty) const {
226 // Round up to the next alignment boundary.
227 return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
230 /// getTypeAllocSizeInBits - Return the offset in bits between successive
231 /// objects of the specified type, including alignment padding; always a
232 /// multiple of 8. This is the amount that alloca reserves for this type.
233 /// For example, returns 96 or 128 for x86_fp80, depending on alignment.
234 uint64_t getTypeAllocSizeInBits(Type* Ty) const {
235 return 8*getTypeAllocSize(Ty);
238 /// getABITypeAlignment - Return the minimum ABI-required alignment for the
240 unsigned getABITypeAlignment(Type *Ty) const;
242 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
243 /// an integer type of the specified bitwidth.
244 unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
247 /// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
248 /// for the specified type when it is part of a call frame.
249 unsigned getCallFrameTypeAlignment(Type *Ty) const;
252 /// getPrefTypeAlignment - Return the preferred stack/global alignment for
253 /// the specified type. This is always at least as good as the ABI alignment.
254 unsigned getPrefTypeAlignment(Type *Ty) const;
256 /// getPreferredTypeAlignmentShift - Return the preferred alignment for the
257 /// specified type, returned as log2 of the value (a shift amount).
259 unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
261 /// getIntPtrType - Return an unsigned integer type that is the same size or
262 /// greater to the host pointer size.
264 IntegerType *getIntPtrType(LLVMContext &C) const;
266 /// getIndexedOffset - return the offset from the beginning of the type for
267 /// the specified indices. This is used to implement getelementptr.
269 uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
271 /// getStructLayout - Return a StructLayout object, indicating the alignment
272 /// of the struct, its size, and the offsets of its fields. Note that this
273 /// information is lazily cached.
274 const StructLayout *getStructLayout(StructType *Ty) const;
276 /// getPreferredAlignment - Return the preferred alignment of the specified
277 /// global. This includes an explicitly requested alignment (if the global
279 unsigned getPreferredAlignment(const GlobalVariable *GV) const;
281 /// getPreferredAlignmentLog - Return the preferred alignment of the
282 /// specified global, returned in log form. This includes an explicitly
283 /// requested alignment (if the global has one).
284 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
286 /// RoundUpAlignment - Round the specified value up to the next alignment
287 /// boundary specified by Alignment. For example, 7 rounded up to an
288 /// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
289 /// is 8 because it is already aligned.
290 template <typename UIntTy>
291 static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
292 assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
293 return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
296 static char ID; // Pass identification, replacement for typeid
299 /// StructLayout - used to lazily calculate structure layout information for a
300 /// target machine, based on the TargetData structure.
304 unsigned StructAlignment;
305 unsigned NumElements;
306 uint64_t MemberOffsets[1]; // variable sized array!
309 uint64_t getSizeInBytes() const {
313 uint64_t getSizeInBits() const {
317 unsigned getAlignment() const {
318 return StructAlignment;
321 /// getElementContainingOffset - Given a valid byte offset into the structure,
322 /// return the structure index that contains it.
324 unsigned getElementContainingOffset(uint64_t Offset) const;
326 uint64_t getElementOffset(unsigned Idx) const {
327 assert(Idx < NumElements && "Invalid element idx!");
328 return MemberOffsets[Idx];
331 uint64_t getElementOffsetInBits(unsigned Idx) const {
332 return getElementOffset(Idx)*8;
336 friend class TargetData; // Only TargetData can create this class
337 StructLayout(StructType *ST, const TargetData &TD);
340 } // End llvm namespace