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 "Support/Annotation.h"
25 #include "Support/DataTypes.h"
35 class TargetData : public ImmutablePass {
36 bool LittleEndian; // Defaults to false
37 unsigned char ByteAlignment; // Defaults to 1 bytes
38 unsigned char ShortAlignment; // Defaults to 2 bytes
39 unsigned char IntAlignment; // Defaults to 4 bytes
40 unsigned char LongAlignment; // Defaults to 8 bytes
41 unsigned char FloatAlignment; // Defaults to 4 bytes
42 unsigned char DoubleAlignment; // Defaults to 8 bytes
43 unsigned char PointerSize; // Defaults to 8 bytes
44 unsigned char PointerAlignment; // Defaults to 8 bytes
45 AnnotationID AID; // AID for structure layout annotation
47 static Annotation *TypeAnFactory(AnnotationID, const Annotable *, void *);
49 TargetData(const std::string &TargetName = "",
50 bool LittleEndian = false,
51 unsigned char PtrSize = 8,
52 unsigned char PtrAl = 8, unsigned char DoubleAl = 8,
53 unsigned char FloatAl = 4, unsigned char LongAl = 8,
54 unsigned char IntAl = 4, unsigned char ShortAl = 2,
55 unsigned char ByteAl = 1);
56 TargetData(const std::string &ToolName, const Module *M);
57 ~TargetData(); // Not virtual, do not subclass this class
59 /// Target endianness...
60 bool isLittleEndian() const { return LittleEndian; }
61 bool isBigEndian() const { return !LittleEndian; }
63 /// Target alignment constraints
64 unsigned char getByteAlignment() const { return ByteAlignment; }
65 unsigned char getShortAlignment() const { return ShortAlignment; }
66 unsigned char getIntAlignment() const { return IntAlignment; }
67 unsigned char getLongAlignment() const { return LongAlignment; }
68 unsigned char getFloatAlignment() const { return FloatAlignment; }
69 unsigned char getDoubleAlignment() const { return DoubleAlignment; }
70 unsigned char getPointerAlignment() const { return PointerAlignment; }
71 unsigned char getPointerSize() const { return PointerSize; }
72 AnnotationID getStructLayoutAID() const { return AID; }
74 // getTypeSize - Return the number of bytes necessary to hold the specified
76 uint64_t getTypeSize (const Type *Ty) const;
78 // getTypeAlignment - Return the minimum required alignment for the specified
80 unsigned char getTypeAlignment(const Type *Ty) const;
82 // getIndexOffset - return the offset from the beginning of the type for the
83 // specified indices. This is used to implement getelementptr.
85 uint64_t getIndexedOffset(const Type *Ty,
86 const std::vector<Value*> &Indices) const;
88 inline const StructLayout *getStructLayout(const StructType *Ty) const {
89 return (const StructLayout*)
90 ((const Annotable*)Ty)->getOrCreateAnnotation(AID);
94 // This annotation (attached ONLY to StructType classes) is used to lazily
95 // calculate structure layout information for a target machine, based on the
96 // TargetData structure.
98 struct StructLayout : public Annotation {
99 std::vector<uint64_t> MemberOffsets;
101 unsigned StructAlignment;
103 friend class TargetData; // Only TargetData can create this class
104 inline StructLayout(const StructType *ST, const TargetData &TD);
107 } // End llvm namespace