1 //===-- llvm/Target/TargetData.h - Data size & alignment info ---*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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/Support/DataTypes.h"
25 #include "llvm/ADT/SmallVector.h"
36 /// Enum used to categorize the alignment types stored by TargetAlignElem
38 INTEGER_ALIGN = 'i', ///< Integer type alignment
39 PACKED_ALIGN = 'v', ///< Vector type alignment
40 FLOAT_ALIGN = 'f', ///< Floating point type alignment
41 AGGREGATE_ALIGN = 'a' ///< Aggregate alignment
43 /// Target alignment element.
45 /// Stores the alignment data associated with a given alignment type (pointer,
46 /// integer, packed/vector, float) and type bit width.
48 /// @note The unusual order of elements in the structure attempts to reduce
49 /// padding and make the structure slightly more cache friendly.
50 struct TargetAlignElem {
51 unsigned char AlignType; //< Alignment type (AlignTypeEnum)
52 unsigned char ABIAlign; //< ABI alignment for this type/bitw
53 unsigned char PrefAlign; //< Pref. alignment for this type/bitw
54 short TypeBitWidth; //< Type bit width
57 static TargetAlignElem get(AlignTypeEnum align_type, unsigned char abi_align,
58 unsigned char pref_align, short bit_width);
59 /// Less-than predicate
60 bool operator<(const TargetAlignElem &rhs) const;
61 /// Equality predicate
62 bool operator==(const TargetAlignElem &rhs) const;
63 /// output stream operator
64 std::ostream &dump(std::ostream &os) const;
67 //! TargetAlignElem output stream inserter
69 @sa TargetAlignElem::dump()
71 std::ostream &operator<<(std::ostream &os, const TargetAlignElem &elem);
73 class TargetData : public ImmutablePass {
75 bool LittleEndian; ///< Defaults to false
76 unsigned char PointerMemSize; ///< Pointer size in bytes
77 unsigned char PointerABIAlign; ///< Pointer ABI alignment
78 unsigned char PointerPrefAlign; ///< Pointer preferred global alignment
80 //! Where the primitive type alignment data is stored.
83 @note Could support multiple size pointer alignments, e.g., 32-bit pointers
84 vs. 64-bit pointers by extending TargetAlignment, but for now, we don't.
86 SmallVector<TargetAlignElem, 16> Alignments;
87 //! Alignment iterator shorthand
88 typedef SmallVector<TargetAlignElem, 16>::iterator align_iterator;
89 //! Constant alignment iterator shorthand
90 typedef SmallVector<TargetAlignElem, 16>::const_iterator align_const_iterator;
91 //! Invalid alignment.
93 This member is a signal that a requested alignment type and bit width were
94 not found in the SmallVector.
96 static const TargetAlignElem InvalidAlignmentElem;
98 //! Set/initialize target alignments
99 void setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
100 unsigned char pref_align, short bit_width);
101 //! Get TargetAlignElem from alignment type and bit width
102 const TargetAlignElem &getAlignment(AlignTypeEnum, short) const;
103 //! Internal helper method that returns requested alignment for type.
104 unsigned char getAlignment(const Type *Ty, bool abi_or_pref) const;
106 /// Valid alignment predicate.
108 /// Predicate that tests a TargetAlignElem reference returned by get() against
109 /// InvalidAlignmentElem.
110 inline bool validAlignment(const TargetAlignElem &align) const {
111 return (&align != &InvalidAlignmentElem);
117 /// @note This has to exist, because this is a pass, but it should never be
120 assert(0 && "ERROR: Bad TargetData ctor used. "
121 "Tool did not specify a TargetData to use?");
125 /// Constructs a TargetData from a specification string. See init().
126 TargetData(const std::string &TargetDescription) {
127 init(TargetDescription);
130 /// Initialize target data from properties stored in the module.
131 TargetData(const Module *M);
133 TargetData(const TargetData &TD) :
135 LittleEndian(TD.isLittleEndian()),
136 PointerMemSize(TD.PointerMemSize),
137 PointerABIAlign(TD.PointerABIAlign),
138 PointerPrefAlign(TD.PointerPrefAlign),
139 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(const std::string &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;
155 /// Target pointer alignment
156 unsigned char getPointerABIAlignment() const { return PointerABIAlign; }
157 /// Return target's alignment for stack-based pointers
158 unsigned char getPointerPrefAlignment() const { return PointerPrefAlign; }
159 /// Target pointer size
160 unsigned char getPointerSize() const { return PointerMemSize; }
161 /// Target pointer size, in bits
162 unsigned char getPointerSizeInBits() const { return 8*PointerMemSize; }
164 /// getTypeSize - Return the number of bytes necessary to hold the specified
166 uint64_t getTypeSize(const Type *Ty) const;
168 /// getTypeSizeInBits - Return the number of bytes necessary to hold the
170 uint64_t getTypeSizeInBits(const Type* Ty) const;
172 /// getTypeAlignmentABI - Return the minimum ABI-required alignment for the
174 unsigned char getABITypeAlignment(const Type *Ty) const;
176 /// getTypeAlignmentPref - Return the preferred stack/global alignment for
177 /// the specified type.
178 unsigned char getPrefTypeAlignment(const Type *Ty) const;
180 /// getPreferredTypeAlignmentShift - Return the preferred alignment for the
181 /// specified type, returned as log2 of the value (a shift amount).
183 unsigned char getPreferredTypeAlignmentShift(const Type *Ty) const;
185 /// getIntPtrType - Return an unsigned integer type that is the same size or
186 /// greater to the host pointer size.
188 const Type *getIntPtrType() const;
190 /// getIndexOffset - return the offset from the beginning of the type for the
191 /// specified indices. This is used to implement getelementptr.
193 uint64_t getIndexedOffset(const Type *Ty,
194 Value* const* Indices, unsigned NumIndices) const;
196 /// getStructLayout - Return a StructLayout object, indicating the alignment
197 /// of the struct, its size, and the offsets of its fields. Note that this
198 /// information is lazily cached.
199 const StructLayout *getStructLayout(const StructType *Ty) const;
201 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
202 /// objects. If a TargetData object is alive when types are being refined and
203 /// removed, this method must be called whenever a StructType is removed to
204 /// avoid a dangling pointer in this cache.
205 void InvalidateStructLayoutInfo(const StructType *Ty) const;
207 /// getPreferredAlignmentLog - Return the preferred alignment of the
208 /// specified global, returned in log form. This includes an explicitly
209 /// requested alignment (if the global has one).
210 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
213 /// StructLayout - used to lazily calculate structure layout information for a
214 /// target machine, based on the TargetData structure.
218 unsigned StructAlignment;
219 unsigned NumElements;
220 uint64_t MemberOffsets[1]; // variable sized array!
223 uint64_t getSizeInBytes() const {
227 unsigned getAlignment() const {
228 return StructAlignment;
231 /// getElementContainingOffset - Given a valid offset into the structure,
232 /// return the structure index that contains it.
234 unsigned getElementContainingOffset(uint64_t Offset) const;
236 uint64_t getElementOffset(unsigned Idx) const {
237 assert(Idx < NumElements && "Invalid element idx!");
238 return MemberOffsets[Idx];
242 friend class TargetData; // Only TargetData can create this class
243 StructLayout(const StructType *ST, const TargetData &TD);
246 } // End llvm namespace