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"
37 /// Enum used to categorize the alignment types stored by TargetAlignElem
39 INTEGER_ALIGN = 'i', ///< Integer type alignment
40 VECTOR_ALIGN = 'v', ///< Vector type alignment
41 FLOAT_ALIGN = 'f', ///< Floating point type alignment
42 AGGREGATE_ALIGN = 'a', ///< Aggregate alignment
43 STACK_ALIGN = 's' ///< Stack objects alignment
45 /// Target alignment element.
47 /// Stores the alignment data associated with a given alignment type (pointer,
48 /// integer, vector, float) and type bit width.
50 /// @note The unusual order of elements in the structure attempts to reduce
51 /// padding and make the structure slightly more cache friendly.
52 struct TargetAlignElem {
53 AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum)
54 unsigned ABIAlign; //< ABI alignment for this type/bitw
55 unsigned PrefAlign; //< Pref. alignment for this type/bitw
56 uint32_t TypeBitWidth; //< Type bit width
59 static TargetAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
60 unsigned pref_align, uint32_t bit_width);
61 /// Equality predicate
62 bool operator==(const TargetAlignElem &rhs) const;
65 class TargetData : public ImmutablePass {
67 bool LittleEndian; ///< Defaults to false
68 unsigned PointerMemSize; ///< Pointer size in bytes
69 unsigned PointerABIAlign; ///< Pointer ABI alignment
70 unsigned PointerPrefAlign; ///< Pointer preferred alignment
72 SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
74 /// Alignments- Where the primitive type alignment data is stored.
77 /// @note Could support multiple size pointer alignments, e.g., 32-bit
78 /// pointers vs. 64-bit pointers by extending TargetAlignment, but for now,
80 SmallVector<TargetAlignElem, 16> Alignments;
82 /// InvalidAlignmentElem - This member is a signal that a requested alignment
83 /// type and bit width were not found in the SmallVector.
84 static const TargetAlignElem InvalidAlignmentElem;
86 // The StructType -> StructLayout map.
87 mutable void *LayoutMap;
89 //! Set/initialize target alignments
90 void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
91 unsigned pref_align, uint32_t bit_width);
92 unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
93 bool ABIAlign, const Type *Ty) const;
94 //! Internal helper method that returns requested alignment for type.
95 unsigned getAlignment(const Type *Ty, bool abi_or_pref) const;
97 /// Valid alignment predicate.
99 /// Predicate that tests a TargetAlignElem reference returned by get() against
100 /// InvalidAlignmentElem.
101 bool validAlignment(const TargetAlignElem &align) const {
102 return &align != &InvalidAlignmentElem;
108 /// @note This has to exist, because this is a pass, but it should never be
112 /// Constructs a TargetData from a specification string. See init().
113 explicit TargetData(StringRef TargetDescription)
114 : ImmutablePass(ID) {
115 init(TargetDescription);
118 /// Initialize target data from properties stored in the module.
119 explicit TargetData(const Module *M);
121 TargetData(const TargetData &TD) :
123 LittleEndian(TD.isLittleEndian()),
124 PointerMemSize(TD.PointerMemSize),
125 PointerABIAlign(TD.PointerABIAlign),
126 PointerPrefAlign(TD.PointerPrefAlign),
127 LegalIntWidths(TD.LegalIntWidths),
128 Alignments(TD.Alignments),
132 ~TargetData(); // Not virtual, do not subclass this class
134 //! Parse a target data layout string and initialize TargetData alignments.
135 void init(StringRef TargetDescription);
137 /// Target endianness...
138 bool isLittleEndian() const { return LittleEndian; }
139 bool isBigEndian() const { return !LittleEndian; }
141 /// getStringRepresentation - Return the string representation of the
142 /// TargetData. This representation is in the same format accepted by the
143 /// string constructor above.
144 std::string getStringRepresentation() const;
146 /// isLegalInteger - This function returns true if the specified type is
147 /// known to be a native integer type supported by the CPU. For example,
148 /// i64 is not native on most 32-bit CPUs and i37 is not native on any known
149 /// one. This returns false if the integer width is not legal.
151 /// The width is specified in bits.
153 bool isLegalInteger(unsigned Width) const {
154 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
155 if (LegalIntWidths[i] == Width)
160 bool isIllegalInteger(unsigned Width) const {
161 return !isLegalInteger(Width);
164 /// fitsInLegalInteger - This function returns true if the specified type fits
165 /// in a native integer type supported by the CPU. For example, if the CPU
166 /// only supports i32 as a native integer type, then i27 fits in a legal
167 // integer type but i45 does not.
168 bool fitsInLegalInteger(unsigned Width) const {
169 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
170 if (Width <= LegalIntWidths[i])
175 /// Target pointer alignment
176 unsigned getPointerABIAlignment() const { return PointerABIAlign; }
177 /// Return target's alignment for stack-based pointers
178 unsigned getPointerPrefAlignment() const { return PointerPrefAlign; }
179 /// Target pointer size
180 unsigned getPointerSize() const { return PointerMemSize; }
181 /// Target pointer size, in bits
182 unsigned getPointerSizeInBits() const { return 8*PointerMemSize; }
186 /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
187 /// ---- ---------- --------------- ---------------
196 /// X86_FP80 80 80 96
198 /// [*] The alloc size depends on the alignment, and thus on the target.
199 /// These values are for x86-32 linux.
201 /// getTypeSizeInBits - Return the number of bits necessary to hold the
202 /// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
203 uint64_t getTypeSizeInBits(const Type* Ty) const;
205 /// getTypeStoreSize - Return the maximum number of bytes that may be
206 /// overwritten by storing the specified type. For example, returns 5
207 /// for i36 and 10 for x86_fp80.
208 uint64_t getTypeStoreSize(const Type *Ty) const {
209 return (getTypeSizeInBits(Ty)+7)/8;
212 /// getTypeStoreSizeInBits - Return the maximum number of bits that may be
213 /// overwritten by storing the specified type; always a multiple of 8. For
214 /// example, returns 40 for i36 and 80 for x86_fp80.
215 uint64_t getTypeStoreSizeInBits(const Type *Ty) const {
216 return 8*getTypeStoreSize(Ty);
219 /// getTypeAllocSize - Return the offset in bytes between successive objects
220 /// of the specified type, including alignment padding. This is the amount
221 /// that alloca reserves for this type. For example, returns 12 or 16 for
222 /// x86_fp80, depending on alignment.
223 uint64_t getTypeAllocSize(const Type* Ty) const {
224 // Round up to the next alignment boundary.
225 return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
228 /// getTypeAllocSizeInBits - Return the offset in bits between successive
229 /// objects of the specified type, including alignment padding; always a
230 /// multiple of 8. This is the amount that alloca reserves for this type.
231 /// For example, returns 96 or 128 for x86_fp80, depending on alignment.
232 uint64_t getTypeAllocSizeInBits(const Type* Ty) const {
233 return 8*getTypeAllocSize(Ty);
236 /// getABITypeAlignment - Return the minimum ABI-required alignment for the
238 unsigned getABITypeAlignment(const Type *Ty) const;
240 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
241 /// an integer type of the specified bitwidth.
242 unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
245 /// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
246 /// for the specified type when it is part of a call frame.
247 unsigned getCallFrameTypeAlignment(const Type *Ty) const;
250 /// getPrefTypeAlignment - Return the preferred stack/global alignment for
251 /// the specified type. This is always at least as good as the ABI alignment.
252 unsigned getPrefTypeAlignment(const Type *Ty) const;
254 /// getPreferredTypeAlignmentShift - Return the preferred alignment for the
255 /// specified type, returned as log2 of the value (a shift amount).
257 unsigned getPreferredTypeAlignmentShift(const Type *Ty) const;
259 /// getIntPtrType - Return an unsigned integer type that is the same size or
260 /// greater to the host pointer size.
262 const IntegerType *getIntPtrType(LLVMContext &C) const;
264 /// getIndexedOffset - return the offset from the beginning of the type for
265 /// the specified indices. This is used to implement getelementptr.
267 uint64_t getIndexedOffset(const Type *Ty,
268 Value* const* Indices, unsigned NumIndices) const;
270 /// getStructLayout - Return a StructLayout object, indicating the alignment
271 /// of the struct, its size, and the offsets of its fields. Note that this
272 /// information is lazily cached.
273 const StructLayout *getStructLayout(const StructType *Ty) const;
275 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
276 /// objects. If a TargetData object is alive when types are being refined and
277 /// removed, this method must be called whenever a StructType is removed to
278 /// avoid a dangling pointer in this cache.
279 void InvalidateStructLayoutInfo(const StructType *Ty) const;
281 /// getPreferredAlignment - Return the preferred alignment of the specified
282 /// global. This includes an explicitly requested alignment (if the global
284 unsigned getPreferredAlignment(const GlobalVariable *GV) const;
286 /// getPreferredAlignmentLog - Return the preferred alignment of the
287 /// specified global, returned in log form. This includes an explicitly
288 /// requested alignment (if the global has one).
289 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
291 /// RoundUpAlignment - Round the specified value up to the next alignment
292 /// boundary specified by Alignment. For example, 7 rounded up to an
293 /// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
294 /// is 8 because it is already aligned.
295 template <typename UIntTy>
296 static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
297 assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
298 return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
301 static char ID; // Pass identification, replacement for typeid
304 /// StructLayout - used to lazily calculate structure layout information for a
305 /// target machine, based on the TargetData structure.
309 unsigned StructAlignment;
310 unsigned NumElements;
311 uint64_t MemberOffsets[1]; // variable sized array!
314 uint64_t getSizeInBytes() const {
318 uint64_t getSizeInBits() const {
322 unsigned getAlignment() const {
323 return StructAlignment;
326 /// getElementContainingOffset - Given a valid byte offset into the structure,
327 /// return the structure index that contains it.
329 unsigned getElementContainingOffset(uint64_t Offset) const;
331 uint64_t getElementOffset(unsigned Idx) const {
332 assert(Idx < NumElements && "Invalid element idx!");
333 return MemberOffsets[Idx];
336 uint64_t getElementOffsetInBits(unsigned Idx) const {
337 return getElementOffset(Idx)*8;
341 friend class TargetData; // Only TargetData can create this class
342 StructLayout(const StructType *ST, const TargetData &TD);
345 } // End llvm namespace