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
48 /// Target alignment element.
50 /// Stores the alignment data associated with a given alignment type (pointer,
51 /// integer, vector, float) and type bit width.
53 /// @note The unusual order of elements in the structure attempts to reduce
54 /// padding and make the structure slightly more cache friendly.
55 struct TargetAlignElem {
56 AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum)
57 unsigned ABIAlign; //< ABI alignment for this type/bitw
58 unsigned PrefAlign; //< Pref. alignment for this type/bitw
59 uint32_t TypeBitWidth; //< Type bit width
62 static TargetAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
63 unsigned pref_align, uint32_t bit_width);
64 /// Equality predicate
65 bool operator==(const TargetAlignElem &rhs) const;
68 /// TargetData - This class holds a parsed version of the target data layout
69 /// string in a module and provides methods for querying it. The target data
70 /// layout string is specified *by the target* - a frontend generating LLVM IR
71 /// is required to generate the right target data for the target being codegen'd
72 /// to. If some measure of portability is desired, an empty string may be
73 /// specified in the module.
74 class TargetData : public ImmutablePass {
76 bool LittleEndian; ///< Defaults to false
77 unsigned PointerMemSize; ///< Pointer size in bytes
78 unsigned PointerABIAlign; ///< Pointer ABI alignment
79 unsigned PointerPrefAlign; ///< Pointer preferred alignment
80 unsigned StackNaturalAlign; ///< Stack natural alignment
82 SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
84 /// Alignments- Where the primitive type alignment data is stored.
87 /// @note Could support multiple size pointer alignments, e.g., 32-bit
88 /// pointers vs. 64-bit pointers by extending TargetAlignment, but for now,
90 SmallVector<TargetAlignElem, 16> Alignments;
92 /// InvalidAlignmentElem - This member is a signal that a requested alignment
93 /// type and bit width were not found in the SmallVector.
94 static const TargetAlignElem InvalidAlignmentElem;
96 // The StructType -> StructLayout map.
97 mutable void *LayoutMap;
99 //! Set/initialize target alignments
100 void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
101 unsigned pref_align, uint32_t bit_width);
102 unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
103 bool ABIAlign, Type *Ty) const;
104 //! Internal helper method that returns requested alignment for type.
105 unsigned getAlignment(Type *Ty, bool abi_or_pref) const;
107 /// Valid alignment predicate.
109 /// Predicate that tests a TargetAlignElem reference returned by get() against
110 /// InvalidAlignmentElem.
111 bool validAlignment(const TargetAlignElem &align) const {
112 return &align != &InvalidAlignmentElem;
118 /// @note This has to exist, because this is a pass, but it should never be
122 /// Constructs a TargetData from a specification string. See init().
123 explicit TargetData(StringRef TargetDescription)
124 : ImmutablePass(ID) {
125 init(TargetDescription);
128 /// Initialize target data from properties stored in the module.
129 explicit TargetData(const Module *M);
131 TargetData(const TargetData &TD) :
133 LittleEndian(TD.isLittleEndian()),
134 PointerMemSize(TD.PointerMemSize),
135 PointerABIAlign(TD.PointerABIAlign),
136 PointerPrefAlign(TD.PointerPrefAlign),
137 LegalIntWidths(TD.LegalIntWidths),
138 Alignments(TD.Alignments),
142 ~TargetData(); // Not virtual, do not subclass this class
144 //! Parse a target data layout string and initialize TargetData alignments.
145 void init(StringRef TargetDescription);
147 /// Target endianness...
148 bool isLittleEndian() const { return LittleEndian; }
149 bool isBigEndian() const { return !LittleEndian; }
151 /// getStringRepresentation - Return the string representation of the
152 /// TargetData. This representation is in the same format accepted by the
153 /// string constructor above.
154 std::string getStringRepresentation() const;
156 /// isLegalInteger - This function returns true if the specified type is
157 /// known to be a native integer type supported by the CPU. For example,
158 /// i64 is not native on most 32-bit CPUs and i37 is not native on any known
159 /// one. This returns false if the integer width is not legal.
161 /// The width is specified in bits.
163 bool isLegalInteger(unsigned Width) const {
164 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
165 if (LegalIntWidths[i] == Width)
170 bool isIllegalInteger(unsigned Width) const {
171 return !isLegalInteger(Width);
174 /// Returns true if the given alignment exceeds the natural stack alignment.
175 bool exceedsNaturalStackAlignment(unsigned Align) const {
176 return (StackNaturalAlign != 0) && (Align > StackNaturalAlign);
179 /// fitsInLegalInteger - This function returns true if the specified type fits
180 /// in a native integer type supported by the CPU. For example, if the CPU
181 /// only supports i32 as a native integer type, then i27 fits in a legal
182 // integer type but i45 does not.
183 bool fitsInLegalInteger(unsigned Width) const {
184 for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
185 if (Width <= LegalIntWidths[i])
190 /// Target pointer alignment
191 unsigned getPointerABIAlignment() const { return PointerABIAlign; }
192 /// Return target's alignment for stack-based pointers
193 unsigned getPointerPrefAlignment() const { return PointerPrefAlign; }
194 /// Target pointer size
195 unsigned getPointerSize() const { return PointerMemSize; }
196 /// Target pointer size, in bits
197 unsigned getPointerSizeInBits() const { return 8*PointerMemSize; }
201 /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
202 /// ---- ---------- --------------- ---------------
211 /// X86_FP80 80 80 96
213 /// [*] The alloc size depends on the alignment, and thus on the target.
214 /// These values are for x86-32 linux.
216 /// getTypeSizeInBits - Return the number of bits necessary to hold the
217 /// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
218 uint64_t getTypeSizeInBits(Type* Ty) const;
220 /// getTypeStoreSize - Return the maximum number of bytes that may be
221 /// overwritten by storing the specified type. For example, returns 5
222 /// for i36 and 10 for x86_fp80.
223 uint64_t getTypeStoreSize(Type *Ty) const {
224 return (getTypeSizeInBits(Ty)+7)/8;
227 /// getTypeStoreSizeInBits - Return the maximum number of bits that may be
228 /// overwritten by storing the specified type; always a multiple of 8. For
229 /// example, returns 40 for i36 and 80 for x86_fp80.
230 uint64_t getTypeStoreSizeInBits(Type *Ty) const {
231 return 8*getTypeStoreSize(Ty);
234 /// getTypeAllocSize - Return the offset in bytes between successive objects
235 /// of the specified type, including alignment padding. This is the amount
236 /// that alloca reserves for this type. For example, returns 12 or 16 for
237 /// x86_fp80, depending on alignment.
238 uint64_t getTypeAllocSize(Type* Ty) const {
239 // Round up to the next alignment boundary.
240 return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
243 /// getTypeAllocSizeInBits - Return the offset in bits between successive
244 /// objects of the specified type, including alignment padding; always a
245 /// multiple of 8. This is the amount that alloca reserves for this type.
246 /// For example, returns 96 or 128 for x86_fp80, depending on alignment.
247 uint64_t getTypeAllocSizeInBits(Type* Ty) const {
248 return 8*getTypeAllocSize(Ty);
251 /// getABITypeAlignment - Return the minimum ABI-required alignment for the
253 unsigned getABITypeAlignment(Type *Ty) const;
255 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
256 /// an integer type of the specified bitwidth.
257 unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
260 /// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
261 /// for the specified type when it is part of a call frame.
262 unsigned getCallFrameTypeAlignment(Type *Ty) const;
265 /// getPrefTypeAlignment - Return the preferred stack/global alignment for
266 /// the specified type. This is always at least as good as the ABI alignment.
267 unsigned getPrefTypeAlignment(Type *Ty) const;
269 /// getPreferredTypeAlignmentShift - Return the preferred alignment for the
270 /// specified type, returned as log2 of the value (a shift amount).
272 unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
274 /// getIntPtrType - Return an unsigned integer type that is the same size or
275 /// greater to the host pointer size.
277 IntegerType *getIntPtrType(LLVMContext &C) const;
279 /// getIndexedOffset - return the offset from the beginning of the type for
280 /// the specified indices. This is used to implement getelementptr.
282 uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
284 /// getStructLayout - Return a StructLayout object, indicating the alignment
285 /// of the struct, its size, and the offsets of its fields. Note that this
286 /// information is lazily cached.
287 const StructLayout *getStructLayout(StructType *Ty) const;
289 /// getPreferredAlignment - Return the preferred alignment of the specified
290 /// global. This includes an explicitly requested alignment (if the global
292 unsigned getPreferredAlignment(const GlobalVariable *GV) const;
294 /// getPreferredAlignmentLog - Return the preferred alignment of the
295 /// specified global, returned in log form. This includes an explicitly
296 /// requested alignment (if the global has one).
297 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
299 /// RoundUpAlignment - Round the specified value up to the next alignment
300 /// boundary specified by Alignment. For example, 7 rounded up to an
301 /// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
302 /// is 8 because it is already aligned.
303 template <typename UIntTy>
304 static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
305 assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
306 return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
309 static char ID; // Pass identification, replacement for typeid
312 /// StructLayout - used to lazily calculate structure layout information for a
313 /// target machine, based on the TargetData structure.
317 unsigned StructAlignment;
318 unsigned NumElements;
319 uint64_t MemberOffsets[1]; // variable sized array!
322 uint64_t getSizeInBytes() const {
326 uint64_t getSizeInBits() const {
330 unsigned getAlignment() const {
331 return StructAlignment;
334 /// getElementContainingOffset - Given a valid byte offset into the structure,
335 /// return the structure index that contains it.
337 unsigned getElementContainingOffset(uint64_t Offset) const;
339 uint64_t getElementOffset(unsigned Idx) const {
340 assert(Idx < NumElements && "Invalid element idx!");
341 return MemberOffsets[Idx];
344 uint64_t getElementOffsetInBits(unsigned Idx) const {
345 return getElementOffset(Idx)*8;
349 friend class TargetData; // Only TargetData can create this class
350 StructLayout(StructType *ST, const TargetData &TD);
353 } // End llvm namespace