1 //===--------- llvm/DataLayout.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 layout 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_IR_DATALAYOUT_H
21 #define LLVM_IR_DATALAYOUT_H
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/IR/DerivedTypes.h"
26 #include "llvm/IR/Type.h"
27 #include "llvm/Pass.h"
28 #include "llvm/Support/DataTypes.h"
30 // this needs to be outside of the namespace, to avoid conflict with llvm-c decl
31 typedef struct LLVMOpaqueTargetData *LLVMTargetDataRef;
46 /// Enum used to categorize the alignment types stored by LayoutAlignElem
48 INVALID_ALIGN = 0, ///< An invalid alignment
49 INTEGER_ALIGN = 'i', ///< Integer type alignment
50 VECTOR_ALIGN = 'v', ///< Vector type alignment
51 FLOAT_ALIGN = 'f', ///< Floating point type alignment
52 AGGREGATE_ALIGN = 'a' ///< Aggregate alignment
55 /// Layout alignment element.
57 /// Stores the alignment data associated with a given alignment type (integer,
58 /// vector, float) and type bit width.
60 /// @note The unusual order of elements in the structure attempts to reduce
61 /// padding and make the structure slightly more cache friendly.
62 struct LayoutAlignElem {
63 unsigned AlignType : 8; ///< Alignment type (AlignTypeEnum)
64 unsigned TypeBitWidth : 24; ///< Type bit width
65 unsigned ABIAlign : 16; ///< ABI alignment for this type/bitw
66 unsigned PrefAlign : 16; ///< Pref. alignment for this type/bitw
69 static LayoutAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
70 unsigned pref_align, uint32_t bit_width);
71 /// Equality predicate
72 bool operator==(const LayoutAlignElem &rhs) const;
75 /// Layout pointer alignment element.
77 /// Stores the alignment data associated with a given pointer and address space.
79 /// @note The unusual order of elements in the structure attempts to reduce
80 /// padding and make the structure slightly more cache friendly.
81 struct PointerAlignElem {
82 unsigned ABIAlign; ///< ABI alignment for this type/bitw
83 unsigned PrefAlign; ///< Pref. alignment for this type/bitw
84 uint32_t TypeByteWidth; ///< Type byte width
85 uint32_t AddressSpace; ///< Address space for the pointer type
88 static PointerAlignElem get(uint32_t AddressSpace, unsigned ABIAlign,
89 unsigned PrefAlign, uint32_t TypeByteWidth);
90 /// Equality predicate
91 bool operator==(const PointerAlignElem &rhs) const;
94 /// This class holds a parsed version of the target data layout string in a
95 /// module and provides methods for querying it. The target data layout string
96 /// is specified *by the target* - a frontend generating LLVM IR is required to
97 /// generate the right target data for the target being codegen'd to.
100 bool LittleEndian; ///< Defaults to false
101 unsigned StackNaturalAlign; ///< Stack natural alignment
110 ManglingModeT ManglingMode;
112 SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
114 /// Alignments - Where the primitive type alignment data is stored.
117 /// @note Could support multiple size pointer alignments, e.g., 32-bit
118 /// pointers vs. 64-bit pointers by extending LayoutAlignment, but for now,
120 SmallVector<LayoutAlignElem, 16> Alignments;
121 typedef SmallVector<PointerAlignElem, 8> PointersTy;
124 PointersTy::const_iterator
125 findPointerLowerBound(uint32_t AddressSpace) const {
126 return const_cast<DataLayout *>(this)->findPointerLowerBound(AddressSpace);
129 PointersTy::iterator findPointerLowerBound(uint32_t AddressSpace);
131 /// InvalidAlignmentElem - This member is a signal that a requested alignment
132 /// type and bit width were not found in the SmallVector.
133 static const LayoutAlignElem InvalidAlignmentElem;
135 /// InvalidPointerElem - This member is a signal that a requested pointer
136 /// type and bit width were not found in the DenseSet.
137 static const PointerAlignElem InvalidPointerElem;
139 // The StructType -> StructLayout map.
140 mutable void *LayoutMap;
142 //! Set/initialize target alignments
143 void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
144 unsigned pref_align, uint32_t bit_width);
145 unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
146 bool ABIAlign, Type *Ty) const;
148 //! Set/initialize pointer alignments
149 void setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
150 unsigned PrefAlign, uint32_t TypeByteWidth);
152 //! Internal helper method that returns requested alignment for type.
153 unsigned getAlignment(Type *Ty, bool abi_or_pref) const;
155 /// Valid alignment predicate.
157 /// Predicate that tests a LayoutAlignElem reference returned by get() against
158 /// InvalidAlignmentElem.
159 bool validAlignment(const LayoutAlignElem &align) const {
160 return &align != &InvalidAlignmentElem;
163 /// Valid pointer predicate.
165 /// Predicate that tests a PointerAlignElem reference returned by get() against
166 /// InvalidPointerElem.
167 bool validPointer(const PointerAlignElem &align) const {
168 return &align != &InvalidPointerElem;
171 /// Parses a target data specification string. Assert if the string is
173 void parseSpecifier(StringRef LayoutDescription);
175 // Free all internal data structures.
179 /// Constructs a DataLayout from a specification string. See reset().
180 explicit DataLayout(StringRef LayoutDescription) : LayoutMap(nullptr) {
181 reset(LayoutDescription);
184 /// Initialize target data from properties stored in the module.
185 explicit DataLayout(const Module *M);
187 void init(const Module *M);
189 DataLayout(const DataLayout &DL) : LayoutMap(nullptr) { *this = DL; }
191 DataLayout &operator=(const DataLayout &DL) {
193 LittleEndian = DL.isLittleEndian();
194 StackNaturalAlign = DL.StackNaturalAlign;
195 ManglingMode = DL.ManglingMode;
196 LegalIntWidths = DL.LegalIntWidths;
197 Alignments = DL.Alignments;
198 Pointers = DL.Pointers;
202 bool operator==(const DataLayout &Other) const;
203 bool operator!=(const DataLayout &Other) const { return !(*this == Other); }
205 ~DataLayout(); // Not virtual, do not subclass this class
207 /// Parse a data layout string (with fallback to default values).
208 void reset(StringRef LayoutDescription);
210 /// Layout endianness...
211 bool isLittleEndian() const { return LittleEndian; }
212 bool isBigEndian() const { return !LittleEndian; }
214 /// getStringRepresentation - Return the string representation of the
215 /// DataLayout. This representation is in the same format accepted by the
216 /// string constructor above.
217 std::string getStringRepresentation() const;
219 /// isLegalInteger - This function returns true if the specified type is
220 /// known to be a native integer type supported by the CPU. For example,
221 /// i64 is not native on most 32-bit CPUs and i37 is not native on any known
222 /// one. This returns false if the integer width is not legal.
224 /// The width is specified in bits.
226 bool isLegalInteger(unsigned Width) const {
227 for (unsigned LegalIntWidth : LegalIntWidths)
228 if (LegalIntWidth == Width)
233 bool isIllegalInteger(unsigned Width) const {
234 return !isLegalInteger(Width);
237 /// Returns true if the given alignment exceeds the natural stack alignment.
238 bool exceedsNaturalStackAlignment(unsigned Align) const {
239 return (StackNaturalAlign != 0) && (Align > StackNaturalAlign);
242 bool hasMicrosoftFastStdCallMangling() const {
243 return ManglingMode == MM_WINCOFF;
246 bool hasLinkerPrivateGlobalPrefix() const {
247 return ManglingMode == MM_MachO;
250 const char *getLinkerPrivateGlobalPrefix() const {
251 if (ManglingMode == MM_MachO)
253 return getPrivateGlobalPrefix();
256 char getGlobalPrefix() const {
257 switch (ManglingMode) {
266 llvm_unreachable("invalid mangling mode");
269 const char *getPrivateGlobalPrefix() const {
270 switch (ManglingMode) {
281 llvm_unreachable("invalid mangling mode");
284 static const char *getManglingComponent(const Triple &T);
286 /// fitsInLegalInteger - This function returns true if the specified type fits
287 /// in a native integer type supported by the CPU. For example, if the CPU
288 /// only supports i32 as a native integer type, then i27 fits in a legal
289 /// integer type but i45 does not.
290 bool fitsInLegalInteger(unsigned Width) const {
291 for (unsigned LegalIntWidth : LegalIntWidths)
292 if (Width <= LegalIntWidth)
297 /// Layout pointer alignment
298 /// FIXME: The defaults need to be removed once all of
299 /// the backends/clients are updated.
300 unsigned getPointerABIAlignment(unsigned AS = 0) const;
302 /// Return target's alignment for stack-based pointers
303 /// FIXME: The defaults need to be removed once all of
304 /// the backends/clients are updated.
305 unsigned getPointerPrefAlignment(unsigned AS = 0) const;
307 /// Layout pointer size
308 /// FIXME: The defaults need to be removed once all of
309 /// the backends/clients are updated.
310 unsigned getPointerSize(unsigned AS = 0) const;
312 /// Layout pointer size, in bits
313 /// FIXME: The defaults need to be removed once all of
314 /// the backends/clients are updated.
315 unsigned getPointerSizeInBits(unsigned AS = 0) const {
316 return getPointerSize(AS) * 8;
319 /// Layout pointer size, in bits, based on the type. If this function is
320 /// called with a pointer type, then the type size of the pointer is returned.
321 /// If this function is called with a vector of pointers, then the type size
322 /// of the pointer is returned. This should only be called with a pointer or
323 /// vector of pointers.
324 unsigned getPointerTypeSizeInBits(Type *) const;
326 unsigned getPointerTypeSize(Type *Ty) const {
327 return getPointerTypeSizeInBits(Ty) / 8;
332 /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
333 /// ---- ---------- --------------- ---------------
342 /// X86_FP80 80 80 96
344 /// [*] The alloc size depends on the alignment, and thus on the target.
345 /// These values are for x86-32 linux.
347 /// getTypeSizeInBits - Return the number of bits necessary to hold the
348 /// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
349 /// The type passed must have a size (Type::isSized() must return true).
350 uint64_t getTypeSizeInBits(Type *Ty) const;
352 /// getTypeStoreSize - Return the maximum number of bytes that may be
353 /// overwritten by storing the specified type. For example, returns 5
354 /// for i36 and 10 for x86_fp80.
355 uint64_t getTypeStoreSize(Type *Ty) const {
356 return (getTypeSizeInBits(Ty)+7)/8;
359 /// getTypeStoreSizeInBits - Return the maximum number of bits that may be
360 /// overwritten by storing the specified type; always a multiple of 8. For
361 /// example, returns 40 for i36 and 80 for x86_fp80.
362 uint64_t getTypeStoreSizeInBits(Type *Ty) const {
363 return 8*getTypeStoreSize(Ty);
366 /// getTypeAllocSize - Return the offset in bytes between successive objects
367 /// of the specified type, including alignment padding. This is the amount
368 /// that alloca reserves for this type. For example, returns 12 or 16 for
369 /// x86_fp80, depending on alignment.
370 uint64_t getTypeAllocSize(Type *Ty) const {
371 // Round up to the next alignment boundary.
372 return RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
375 /// getTypeAllocSizeInBits - Return the offset in bits between successive
376 /// objects of the specified type, including alignment padding; always a
377 /// multiple of 8. This is the amount that alloca reserves for this type.
378 /// For example, returns 96 or 128 for x86_fp80, depending on alignment.
379 uint64_t getTypeAllocSizeInBits(Type *Ty) const {
380 return 8*getTypeAllocSize(Ty);
383 /// getABITypeAlignment - Return the minimum ABI-required alignment for the
385 unsigned getABITypeAlignment(Type *Ty) const;
387 /// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
388 /// an integer type of the specified bitwidth.
389 unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
391 /// getPrefTypeAlignment - Return the preferred stack/global alignment for
392 /// the specified type. This is always at least as good as the ABI alignment.
393 unsigned getPrefTypeAlignment(Type *Ty) const;
395 /// getPreferredTypeAlignmentShift - Return the preferred alignment for the
396 /// specified type, returned as log2 of the value (a shift amount).
397 unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
399 /// getIntPtrType - Return an integer type with size at least as big as that
400 /// of a pointer in the given address space.
401 IntegerType *getIntPtrType(LLVMContext &C, unsigned AddressSpace = 0) const;
403 /// getIntPtrType - Return an integer (vector of integer) type with size at
404 /// least as big as that of a pointer of the given pointer (vector of pointer)
406 Type *getIntPtrType(Type *) const;
408 /// getSmallestLegalIntType - Return the smallest integer type with size at
409 /// least as big as Width bits.
410 Type *getSmallestLegalIntType(LLVMContext &C, unsigned Width = 0) const;
412 /// getLargestLegalIntType - Return the largest legal integer type, or null if
414 Type *getLargestLegalIntType(LLVMContext &C) const {
415 unsigned LargestSize = getLargestLegalIntTypeSize();
416 return (LargestSize == 0) ? nullptr : Type::getIntNTy(C, LargestSize);
419 /// getLargestLegalIntTypeSize - Return the size of largest legal integer
420 /// type size, or 0 if none are set.
421 unsigned getLargestLegalIntTypeSize() const;
423 /// getIndexedOffset - return the offset from the beginning of the type for
424 /// the specified indices. This is used to implement getelementptr.
425 uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
427 /// getStructLayout - Return a StructLayout object, indicating the alignment
428 /// of the struct, its size, and the offsets of its fields. Note that this
429 /// information is lazily cached.
430 const StructLayout *getStructLayout(StructType *Ty) const;
432 /// getPreferredAlignment - Return the preferred alignment of the specified
433 /// global. This includes an explicitly requested alignment (if the global
435 unsigned getPreferredAlignment(const GlobalVariable *GV) const;
437 /// getPreferredAlignmentLog - Return the preferred alignment of the
438 /// specified global, returned in log form. This includes an explicitly
439 /// requested alignment (if the global has one).
440 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
442 /// RoundUpAlignment - Round the specified value up to the next alignment
443 /// boundary specified by Alignment. For example, 7 rounded up to an
444 /// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
445 /// is 8 because it is already aligned.
446 template <typename UIntTy>
447 static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
448 assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
449 return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
453 inline DataLayout *unwrap(LLVMTargetDataRef P) {
454 return reinterpret_cast<DataLayout*>(P);
457 inline LLVMTargetDataRef wrap(const DataLayout *P) {
458 return reinterpret_cast<LLVMTargetDataRef>(const_cast<DataLayout*>(P));
461 class DataLayoutPass : public ImmutablePass {
465 /// This has to exist, because this is a pass, but it should never be used.
469 const DataLayout &getDataLayout() const { return DL; }
471 static char ID; // Pass identification, replacement for typeid
473 bool doFinalization(Module &M) override;
474 bool doInitialization(Module &M) override;
477 /// StructLayout - used to lazily calculate structure layout information for a
478 /// target machine, based on the DataLayout structure.
482 unsigned StructAlignment;
483 unsigned NumElements;
484 uint64_t MemberOffsets[1]; // variable sized array!
487 uint64_t getSizeInBytes() const {
491 uint64_t getSizeInBits() const {
495 unsigned getAlignment() const {
496 return StructAlignment;
499 /// getElementContainingOffset - Given a valid byte offset into the structure,
500 /// return the structure index that contains it.
502 unsigned getElementContainingOffset(uint64_t Offset) const;
504 uint64_t getElementOffset(unsigned Idx) const {
505 assert(Idx < NumElements && "Invalid element idx!");
506 return MemberOffsets[Idx];
509 uint64_t getElementOffsetInBits(unsigned Idx) const {
510 return getElementOffset(Idx)*8;
514 friend class DataLayout; // Only DataLayout can create this class
515 StructLayout(StructType *ST, const DataLayout &DL);
519 // The implementation of this method is provided inline as it is particularly
520 // well suited to constant folding when called on a specific Type subclass.
521 inline uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const {
522 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
523 switch (Ty->getTypeID()) {
524 case Type::LabelTyID:
525 return getPointerSizeInBits(0);
526 case Type::PointerTyID:
527 return getPointerSizeInBits(Ty->getPointerAddressSpace());
528 case Type::ArrayTyID: {
529 ArrayType *ATy = cast<ArrayType>(Ty);
530 return ATy->getNumElements() *
531 getTypeAllocSizeInBits(ATy->getElementType());
533 case Type::StructTyID:
534 // Get the layout annotation... which is lazily created on demand.
535 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
536 case Type::IntegerTyID:
537 return Ty->getIntegerBitWidth();
540 case Type::FloatTyID:
542 case Type::DoubleTyID:
543 case Type::X86_MMXTyID:
545 case Type::PPC_FP128TyID:
546 case Type::FP128TyID:
548 // In memory objects this is always aligned to a higher boundary, but
549 // only 80 bits contain information.
550 case Type::X86_FP80TyID:
552 case Type::VectorTyID: {
553 VectorType *VTy = cast<VectorType>(Ty);
554 return VTy->getNumElements() * getTypeSizeInBits(VTy->getElementType());
557 llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
561 } // End llvm namespace