llvm-6502/include/llvm/Target/TargetData.h
Dan Gohman b68f274b6d Don't use unsigned char for alignments in TargetData. There aren't
that many of these things, so the memory savings isn't significant,
and there are now situations where there can be alignments greater
than 128.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110836 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-11 18:15:01 +00:00

336 lines
13 KiB
C++

//===-- llvm/Target/TargetData.h - Data size & alignment info ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines target properties related to datatype size/offset/alignment
// information. It uses lazy annotations to cache information about how
// structure types are laid out and used.
//
// This structure should be created once, filled in if the defaults are not
// correct and then passed around by const&. None of the members functions
// require modification to the object.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETDATA_H
#define LLVM_TARGET_TARGETDATA_H
#include "llvm/Pass.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
class Value;
class Type;
class IntegerType;
class StructType;
class StructLayout;
class GlobalVariable;
class LLVMContext;
/// Enum used to categorize the alignment types stored by TargetAlignElem
enum AlignTypeEnum {
INTEGER_ALIGN = 'i', ///< Integer type alignment
VECTOR_ALIGN = 'v', ///< Vector type alignment
FLOAT_ALIGN = 'f', ///< Floating point type alignment
AGGREGATE_ALIGN = 'a', ///< Aggregate alignment
STACK_ALIGN = 's' ///< Stack objects alignment
};
/// Target alignment element.
///
/// Stores the alignment data associated with a given alignment type (pointer,
/// integer, vector, float) and type bit width.
///
/// @note The unusual order of elements in the structure attempts to reduce
/// padding and make the structure slightly more cache friendly.
struct TargetAlignElem {
AlignTypeEnum AlignType : 8; //< Alignment type (AlignTypeEnum)
unsigned ABIAlign; //< ABI alignment for this type/bitw
unsigned PrefAlign; //< Pref. alignment for this type/bitw
uint32_t TypeBitWidth; //< Type bit width
/// Initializer
static TargetAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
unsigned pref_align, uint32_t bit_width);
/// Equality predicate
bool operator==(const TargetAlignElem &rhs) const;
};
class TargetData : public ImmutablePass {
private:
bool LittleEndian; ///< Defaults to false
unsigned PointerMemSize; ///< Pointer size in bytes
unsigned PointerABIAlign; ///< Pointer ABI alignment
unsigned PointerPrefAlign; ///< Pointer preferred alignment
SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
/// Alignments- Where the primitive type alignment data is stored.
///
/// @sa init().
/// @note Could support multiple size pointer alignments, e.g., 32-bit
/// pointers vs. 64-bit pointers by extending TargetAlignment, but for now,
/// we don't.
SmallVector<TargetAlignElem, 16> Alignments;
/// InvalidAlignmentElem - This member is a signal that a requested alignment
/// type and bit width were not found in the SmallVector.
static const TargetAlignElem InvalidAlignmentElem;
// The StructType -> StructLayout map.
mutable void *LayoutMap;
//! Set/initialize target alignments
void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
unsigned pref_align, uint32_t bit_width);
unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
bool ABIAlign, const Type *Ty) const;
//! Internal helper method that returns requested alignment for type.
unsigned getAlignment(const Type *Ty, bool abi_or_pref) const;
/// Valid alignment predicate.
///
/// Predicate that tests a TargetAlignElem reference returned by get() against
/// InvalidAlignmentElem.
bool validAlignment(const TargetAlignElem &align) const {
return &align != &InvalidAlignmentElem;
}
public:
/// Default ctor.
///
/// @note This has to exist, because this is a pass, but it should never be
/// used.
TargetData();
/// Constructs a TargetData from a specification string. See init().
explicit TargetData(StringRef TargetDescription)
: ImmutablePass(ID) {
init(TargetDescription);
}
/// Initialize target data from properties stored in the module.
explicit TargetData(const Module *M);
TargetData(const TargetData &TD) :
ImmutablePass(ID),
LittleEndian(TD.isLittleEndian()),
PointerMemSize(TD.PointerMemSize),
PointerABIAlign(TD.PointerABIAlign),
PointerPrefAlign(TD.PointerPrefAlign),
LegalIntWidths(TD.LegalIntWidths),
Alignments(TD.Alignments),
LayoutMap(0)
{ }
~TargetData(); // Not virtual, do not subclass this class
//! Parse a target data layout string and initialize TargetData alignments.
void init(StringRef TargetDescription);
/// Target endianness...
bool isLittleEndian() const { return LittleEndian; }
bool isBigEndian() const { return !LittleEndian; }
/// getStringRepresentation - Return the string representation of the
/// TargetData. This representation is in the same format accepted by the
/// string constructor above.
std::string getStringRepresentation() const;
/// isLegalInteger - This function returns true if the specified type is
/// known tobe a native integer type supported by the CPU. For example,
/// i64 is not native on most 32-bit CPUs and i37 is not native on any known
/// one. This returns false if the integer width is not legal.
///
/// The width is specified in bits.
///
bool isLegalInteger(unsigned Width) const {
for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
if (LegalIntWidths[i] == Width)
return true;
return false;
}
bool isIllegalInteger(unsigned Width) const {
return !isLegalInteger(Width);
}
/// Target pointer alignment
unsigned getPointerABIAlignment() const { return PointerABIAlign; }
/// Return target's alignment for stack-based pointers
unsigned getPointerPrefAlignment() const { return PointerPrefAlign; }
/// Target pointer size
unsigned getPointerSize() const { return PointerMemSize; }
/// Target pointer size, in bits
unsigned getPointerSizeInBits() const { return 8*PointerMemSize; }
/// Size examples:
///
/// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
/// ---- ---------- --------------- ---------------
/// i1 1 8 8
/// i8 8 8 8
/// i19 19 24 32
/// i32 32 32 32
/// i100 100 104 128
/// i128 128 128 128
/// Float 32 32 32
/// Double 64 64 64
/// X86_FP80 80 80 96
///
/// [*] The alloc size depends on the alignment, and thus on the target.
/// These values are for x86-32 linux.
/// getTypeSizeInBits - Return the number of bits necessary to hold the
/// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
uint64_t getTypeSizeInBits(const Type* Ty) const;
/// getTypeStoreSize - Return the maximum number of bytes that may be
/// overwritten by storing the specified type. For example, returns 5
/// for i36 and 10 for x86_fp80.
uint64_t getTypeStoreSize(const Type *Ty) const {
return (getTypeSizeInBits(Ty)+7)/8;
}
/// getTypeStoreSizeInBits - Return the maximum number of bits that may be
/// overwritten by storing the specified type; always a multiple of 8. For
/// example, returns 40 for i36 and 80 for x86_fp80.
uint64_t getTypeStoreSizeInBits(const Type *Ty) const {
return 8*getTypeStoreSize(Ty);
}
/// getTypeAllocSize - Return the offset in bytes between successive objects
/// of the specified type, including alignment padding. This is the amount
/// that alloca reserves for this type. For example, returns 12 or 16 for
/// x86_fp80, depending on alignment.
uint64_t getTypeAllocSize(const Type* Ty) const {
// Round up to the next alignment boundary.
return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
}
/// getTypeAllocSizeInBits - Return the offset in bits between successive
/// objects of the specified type, including alignment padding; always a
/// multiple of 8. This is the amount that alloca reserves for this type.
/// For example, returns 96 or 128 for x86_fp80, depending on alignment.
uint64_t getTypeAllocSizeInBits(const Type* Ty) const {
return 8*getTypeAllocSize(Ty);
}
/// getABITypeAlignment - Return the minimum ABI-required alignment for the
/// specified type.
unsigned getABITypeAlignment(const Type *Ty) const;
/// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
/// an integer type of the specified bitwidth.
unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
/// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
/// for the specified type when it is part of a call frame.
unsigned getCallFrameTypeAlignment(const Type *Ty) const;
/// getPrefTypeAlignment - Return the preferred stack/global alignment for
/// the specified type. This is always at least as good as the ABI alignment.
unsigned getPrefTypeAlignment(const Type *Ty) const;
/// getPreferredTypeAlignmentShift - Return the preferred alignment for the
/// specified type, returned as log2 of the value (a shift amount).
///
unsigned getPreferredTypeAlignmentShift(const Type *Ty) const;
/// getIntPtrType - Return an unsigned integer type that is the same size or
/// greater to the host pointer size.
///
const IntegerType *getIntPtrType(LLVMContext &C) const;
/// getIndexedOffset - return the offset from the beginning of the type for
/// the specified indices. This is used to implement getelementptr.
///
uint64_t getIndexedOffset(const Type *Ty,
Value* const* Indices, unsigned NumIndices) const;
/// getStructLayout - Return a StructLayout object, indicating the alignment
/// of the struct, its size, and the offsets of its fields. Note that this
/// information is lazily cached.
const StructLayout *getStructLayout(const StructType *Ty) const;
/// InvalidateStructLayoutInfo - TargetData speculatively caches StructLayout
/// objects. If a TargetData object is alive when types are being refined and
/// removed, this method must be called whenever a StructType is removed to
/// avoid a dangling pointer in this cache.
void InvalidateStructLayoutInfo(const StructType *Ty) const;
/// getPreferredAlignment - Return the preferred alignment of the specified
/// global. This includes an explicitly requested alignment (if the global
/// has one).
unsigned getPreferredAlignment(const GlobalVariable *GV) const;
/// getPreferredAlignmentLog - Return the preferred alignment of the
/// specified global, returned in log form. This includes an explicitly
/// requested alignment (if the global has one).
unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
/// RoundUpAlignment - Round the specified value up to the next alignment
/// boundary specified by Alignment. For example, 7 rounded up to an
/// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
/// is 8 because it is already aligned.
template <typename UIntTy>
static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
}
static char ID; // Pass identification, replacement for typeid
};
/// StructLayout - used to lazily calculate structure layout information for a
/// target machine, based on the TargetData structure.
///
class StructLayout {
uint64_t StructSize;
unsigned StructAlignment;
unsigned NumElements;
uint64_t MemberOffsets[1]; // variable sized array!
public:
uint64_t getSizeInBytes() const {
return StructSize;
}
uint64_t getSizeInBits() const {
return 8*StructSize;
}
unsigned getAlignment() const {
return StructAlignment;
}
/// getElementContainingOffset - Given a valid byte offset into the structure,
/// return the structure index that contains it.
///
unsigned getElementContainingOffset(uint64_t Offset) const;
uint64_t getElementOffset(unsigned Idx) const {
assert(Idx < NumElements && "Invalid element idx!");
return MemberOffsets[Idx];
}
uint64_t getElementOffsetInBits(unsigned Idx) const {
return getElementOffset(Idx)*8;
}
private:
friend class TargetData; // Only TargetData can create this class
StructLayout(const StructType *ST, const TargetData &TD);
};
} // End llvm namespace
#endif