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"
35 class TargetData : public ImmutablePass {
36 bool LittleEndian; // Defaults to false
37 unsigned char BoolAlignment; // Defaults to 1 byte
38 unsigned char ByteAlignment; // Defaults to 1 byte
39 unsigned char ShortAlignment; // Defaults to 2 bytes
40 unsigned char IntAlignment; // Defaults to 4 bytes
41 unsigned char LongAlignment; // Defaults to 8 bytes
42 unsigned char FloatAlignment; // Defaults to 4 bytes
43 unsigned char DoubleAlignment; // Defaults to 8 bytes
44 unsigned char PointerSize; // Defaults to 8 bytes
45 unsigned char PointerAlignment; // Defaults to 8 bytes
48 TargetData(const std::string &TargetName = "",
49 bool LittleEndian = false,
50 unsigned char PtrSize = 8,
51 unsigned char PtrAl = 8, unsigned char DoubleAl = 8,
52 unsigned char FloatAl = 4, unsigned char LongAl = 8,
53 unsigned char IntAl = 4, unsigned char ShortAl = 2,
54 unsigned char ByteAl = 1, unsigned char BoolAl = 1);
57 TargetData (const TargetData *TD) :
59 LittleEndian(TD->isLittleEndian()),
60 BoolAlignment(TD->getBoolAlignment()),
61 ByteAlignment(TD->getByteAlignment()),
62 ShortAlignment(TD->getShortAlignment()),
63 IntAlignment(TD->getIntAlignment()),
64 LongAlignment(TD->getLongAlignment()),
65 FloatAlignment(TD->getFloatAlignment()),
66 DoubleAlignment(TD->getDoubleAlignment()),
67 PointerSize(TD->getPointerSize()),
68 PointerAlignment(TD->getPointerAlignment()) {
71 TargetData(const std::string &ToolName, const Module *M);
72 ~TargetData(); // Not virtual, do not subclass this class
74 /// Target endianness...
75 bool isLittleEndian() const { return LittleEndian; }
76 bool isBigEndian() const { return !LittleEndian; }
78 /// Target alignment constraints
79 unsigned char getBoolAlignment() const { return BoolAlignment; }
80 unsigned char getByteAlignment() const { return ByteAlignment; }
81 unsigned char getShortAlignment() const { return ShortAlignment; }
82 unsigned char getIntAlignment() const { return IntAlignment; }
83 unsigned char getLongAlignment() const { return LongAlignment; }
84 unsigned char getFloatAlignment() const { return FloatAlignment; }
85 unsigned char getDoubleAlignment() const { return DoubleAlignment; }
86 unsigned char getPointerAlignment() const { return PointerAlignment; }
87 unsigned char getPointerSize() const { return PointerSize; }
88 unsigned char getPointerSizeInBits() const { return 8*PointerSize; }
90 /// getTypeSize - Return the number of bytes necessary to hold the specified
93 uint64_t getTypeSize(const Type *Ty) const;
95 /// getTypeAlignment - Return the minimum required alignment for the specified
98 unsigned char getTypeAlignment(const Type *Ty) const;
100 /// getTypeAlignmentShift - Return the minimum required alignment for the
101 /// specified type, returned as log2 of the value (a shift amount).
103 unsigned char getTypeAlignmentShift(const Type *Ty) const;
105 /// getIntPtrType - Return an unsigned integer type that is the same size or
106 /// greater to the host pointer size.
108 const Type *getIntPtrType() const;
110 /// getIndexOffset - return the offset from the beginning of the type for the
111 /// specified indices. This is used to implement getelementptr.
113 uint64_t getIndexedOffset(const Type *Ty,
114 const std::vector<Value*> &Indices) const;
116 /// getStructLayout - Return a StructLayout object, indicating the alignment
117 /// of the struct, its size, and the offsets of its fields. Note that this
118 /// information is lazily cached.
119 const StructLayout *getStructLayout(const StructType *Ty) const;
121 /// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
122 /// objects. If a TargetData object is alive when types are being refined and
123 /// removed, this method must be called whenever a StructType is removed to
124 /// avoid a dangling pointer in this cache.
125 void InvalidateStructLayoutInfo(const StructType *Ty) const;
128 /// StructLayout - used to lazily calculate structure layout information for a
129 /// target machine, based on the TargetData structure.
133 std::vector<uint64_t> MemberOffsets;
135 unsigned StructAlignment;
137 /// getElementContainingOffset - Given a valid offset into the structure,
138 /// return the structure index that contains it.
140 unsigned getElementContainingOffset(uint64_t Offset) const;
143 friend class TargetData; // Only TargetData can create this class
144 StructLayout(const StructType *ST, const TargetData &TD);
147 } // End llvm namespace