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
32 typedef struct LLVMOpaqueTargetData *LLVMTargetDataRef;
47 /// Enum used to categorize the alignment types stored by LayoutAlignElem
49 INVALID_ALIGN = 0, ///< An invalid alignment
50 INTEGER_ALIGN = 'i', ///< Integer type alignment
51 VECTOR_ALIGN = 'v', ///< Vector type alignment
52 FLOAT_ALIGN = 'f', ///< Floating point type alignment
53 AGGREGATE_ALIGN = 'a' ///< Aggregate alignment
56 /// \brief Layout alignment element.
58 /// Stores the alignment data associated with a given alignment type (integer,
59 /// vector, float) and type bit width.
61 /// \note The unusual order of elements in the structure attempts to reduce
62 /// padding and make the structure slightly more cache friendly.
63 struct LayoutAlignElem {
64 unsigned AlignType : 8; ///< Alignment type (AlignTypeEnum)
65 unsigned TypeBitWidth : 24; ///< Type bit width
66 unsigned ABIAlign : 16; ///< ABI alignment for this type/bitw
67 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 bool operator==(const LayoutAlignElem &rhs) const;
74 /// \brief Layout pointer alignment element.
76 /// Stores the alignment data associated with a given pointer and address space.
78 /// \note The unusual order of elements in the structure attempts to reduce
79 /// padding and make the structure slightly more cache friendly.
80 struct PointerAlignElem {
81 unsigned ABIAlign; ///< ABI alignment for this type/bitw
82 unsigned PrefAlign; ///< Pref. alignment for this type/bitw
83 uint32_t TypeByteWidth; ///< Type byte width
84 uint32_t AddressSpace; ///< Address space for the pointer type
87 static PointerAlignElem get(uint32_t AddressSpace, unsigned ABIAlign,
88 unsigned PrefAlign, uint32_t TypeByteWidth);
89 bool operator==(const PointerAlignElem &rhs) const;
92 /// \brief A parsed version of the target data layout string in and methods for
95 /// The target data layout string is specified *by the target* - a frontend
96 /// generating LLVM IR is required to generate the right target data for the
97 /// target being codegen'd to.
100 /// Defaults to false.
103 unsigned StackNaturalAlign;
112 ManglingModeT ManglingMode;
114 SmallVector<unsigned char, 8> LegalIntWidths;
116 /// \brief Primitive type alignment data.
117 SmallVector<LayoutAlignElem, 16> Alignments;
119 typedef SmallVector<PointerAlignElem, 8> PointersTy;
122 PointersTy::const_iterator
123 findPointerLowerBound(uint32_t AddressSpace) const {
124 return const_cast<DataLayout *>(this)->findPointerLowerBound(AddressSpace);
127 PointersTy::iterator findPointerLowerBound(uint32_t AddressSpace);
129 /// This member is a signal that a requested alignment type and bit width were
130 /// not found in the SmallVector.
131 static const LayoutAlignElem InvalidAlignmentElem;
133 /// This member is a signal that a requested pointer type and bit width were
134 /// not found in the DenseSet.
135 static const PointerAlignElem InvalidPointerElem;
137 // The StructType -> StructLayout map.
138 mutable void *LayoutMap;
140 void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
141 unsigned pref_align, uint32_t bit_width);
142 unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
143 bool ABIAlign, Type *Ty) const;
144 void setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
145 unsigned PrefAlign, uint32_t TypeByteWidth);
147 /// Internal helper method that returns requested alignment for type.
148 unsigned getAlignment(Type *Ty, bool abi_or_pref) const;
150 /// \brief Valid alignment predicate.
152 /// Predicate that tests a LayoutAlignElem reference returned by get() against
153 /// InvalidAlignmentElem.
154 bool validAlignment(const LayoutAlignElem &align) const {
155 return &align != &InvalidAlignmentElem;
158 /// \brief Valid pointer predicate.
160 /// Predicate that tests a PointerAlignElem reference returned by get() against
161 /// InvalidPointerElem.
162 bool validPointer(const PointerAlignElem &align) const {
163 return &align != &InvalidPointerElem;
166 /// Parses a target data specification string. Assert if the string is
168 void parseSpecifier(StringRef LayoutDescription);
170 // Free all internal data structures.
174 /// Constructs a DataLayout from a specification string. See reset().
175 explicit DataLayout(StringRef LayoutDescription) : LayoutMap(nullptr) {
176 reset(LayoutDescription);
179 /// Initialize target data from properties stored in the module.
180 explicit DataLayout(const Module *M);
182 void init(const Module *M);
184 DataLayout(const DataLayout &DL) : LayoutMap(nullptr) { *this = DL; }
186 DataLayout &operator=(const DataLayout &DL) {
188 LittleEndian = DL.isLittleEndian();
189 StackNaturalAlign = DL.StackNaturalAlign;
190 ManglingMode = DL.ManglingMode;
191 LegalIntWidths = DL.LegalIntWidths;
192 Alignments = DL.Alignments;
193 Pointers = DL.Pointers;
197 bool operator==(const DataLayout &Other) const;
198 bool operator!=(const DataLayout &Other) const { return !(*this == Other); }
200 ~DataLayout(); // Not virtual, do not subclass this class
202 /// Parse a data layout string (with fallback to default values).
203 void reset(StringRef LayoutDescription);
205 /// Layout endianness...
206 bool isLittleEndian() const { return LittleEndian; }
207 bool isBigEndian() const { return !LittleEndian; }
209 /// \brief Returns the string representation of the DataLayout.
211 /// This representation is in the same format accepted by the string
212 /// constructor above.
213 std::string getStringRepresentation() const;
215 /// \brief Returns true if the specified type is known to be a native integer
216 /// type supported by the CPU.
218 /// For example, i64 is not native on most 32-bit CPUs and i37 is not native
219 /// on any known one. This returns false if the integer width is not legal.
221 /// The width is specified in bits.
222 bool isLegalInteger(unsigned Width) const {
223 for (unsigned LegalIntWidth : LegalIntWidths)
224 if (LegalIntWidth == Width)
229 bool isIllegalInteger(unsigned Width) const {
230 return !isLegalInteger(Width);
233 /// Returns true if the given alignment exceeds the natural stack alignment.
234 bool exceedsNaturalStackAlignment(unsigned Align) const {
235 return (StackNaturalAlign != 0) && (Align > StackNaturalAlign);
238 bool hasMicrosoftFastStdCallMangling() const {
239 return ManglingMode == MM_WINCOFF;
242 bool hasLinkerPrivateGlobalPrefix() const {
243 return ManglingMode == MM_MachO;
246 const char *getLinkerPrivateGlobalPrefix() const {
247 if (ManglingMode == MM_MachO)
249 return getPrivateGlobalPrefix();
252 char getGlobalPrefix() const {
253 switch (ManglingMode) {
262 llvm_unreachable("invalid mangling mode");
265 const char *getPrivateGlobalPrefix() const {
266 switch (ManglingMode) {
277 llvm_unreachable("invalid mangling mode");
280 static const char *getManglingComponent(const Triple &T);
282 /// \brief Returns true if the specified type fits in a native integer type
283 /// supported by the CPU.
285 /// For example, if the CPU only supports i32 as a native integer type, then
286 /// i27 fits in a legal integer type but i45 does not.
287 bool fitsInLegalInteger(unsigned Width) const {
288 for (unsigned LegalIntWidth : LegalIntWidths)
289 if (Width <= LegalIntWidth)
294 /// Layout pointer alignment
295 /// FIXME: The defaults need to be removed once all of
296 /// the backends/clients are updated.
297 unsigned getPointerABIAlignment(unsigned AS = 0) const;
299 /// Return target's alignment for stack-based pointers
300 /// FIXME: The defaults need to be removed once all of
301 /// the backends/clients are updated.
302 unsigned getPointerPrefAlignment(unsigned AS = 0) const;
304 /// Layout pointer size
305 /// FIXME: The defaults need to be removed once all of
306 /// the backends/clients are updated.
307 unsigned getPointerSize(unsigned AS = 0) const;
309 /// Layout pointer size, in bits
310 /// FIXME: The defaults need to be removed once all of
311 /// the backends/clients are updated.
312 unsigned getPointerSizeInBits(unsigned AS = 0) const {
313 return getPointerSize(AS) * 8;
316 /// Layout pointer size, in bits, based on the type. If this function is
317 /// called with a pointer type, then the type size of the pointer is returned.
318 /// If this function is called with a vector of pointers, then the type size
319 /// of the pointer is returned. This should only be called with a pointer or
320 /// vector of pointers.
321 unsigned getPointerTypeSizeInBits(Type *) const;
323 unsigned getPointerTypeSize(Type *Ty) const {
324 return getPointerTypeSizeInBits(Ty) / 8;
329 /// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
330 /// ---- ---------- --------------- ---------------
339 /// X86_FP80 80 80 96
341 /// [*] The alloc size depends on the alignment, and thus on the target.
342 /// These values are for x86-32 linux.
344 /// \brief Returns the number of bits necessary to hold the specified type.
346 /// For example, returns 36 for i36 and 80 for x86_fp80. The type passed must
347 /// have a size (Type::isSized() must return true).
348 uint64_t getTypeSizeInBits(Type *Ty) const;
350 /// \brief Returns the maximum number of bytes that may be overwritten by
351 /// storing the specified type.
353 /// For example, returns 5 for i36 and 10 for x86_fp80.
354 uint64_t getTypeStoreSize(Type *Ty) const {
355 return (getTypeSizeInBits(Ty)+7)/8;
358 /// \brief Returns the maximum number of bits that may be overwritten by
359 /// storing the specified type; always a multiple of 8.
361 /// For example, returns 40 for i36 and 80 for x86_fp80.
362 uint64_t getTypeStoreSizeInBits(Type *Ty) const {
363 return 8*getTypeStoreSize(Ty);
366 /// \brief Returns the offset in bytes between successive objects of the
367 /// specified type, including alignment padding.
369 /// This is the amount that alloca reserves for this type. For example,
370 /// returns 12 or 16 for x86_fp80, depending on alignment.
371 uint64_t getTypeAllocSize(Type *Ty) const {
372 // Round up to the next alignment boundary.
373 return RoundUpToAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
376 /// \brief Returns the offset in bits between successive objects of the
377 /// specified type, including alignment padding; always a multiple of 8.
379 /// This is the amount that alloca reserves for this type. For example,
380 /// returns 96 or 128 for x86_fp80, depending on alignment.
381 uint64_t getTypeAllocSizeInBits(Type *Ty) const {
382 return 8*getTypeAllocSize(Ty);
385 /// \brief Returns the minimum ABI-required alignment for the specified type.
386 unsigned getABITypeAlignment(Type *Ty) const;
388 /// \brief Returns the minimum ABI-required alignment for an integer type of
389 /// the specified bitwidth.
390 unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
392 /// \brief Returns the preferred stack/global alignment for the specified
395 /// This is always at least as good as the ABI alignment.
396 unsigned getPrefTypeAlignment(Type *Ty) const;
398 /// \brief Returns the preferred alignment for the specified type, returned as
399 /// log2 of the value (a shift amount).
400 unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
402 /// \brief Returns an integer type with size at least as big as that of a
403 /// pointer in the given address space.
404 IntegerType *getIntPtrType(LLVMContext &C, unsigned AddressSpace = 0) const;
406 /// \brief Returns an integer (vector of integer) type with size at least as
407 /// big as that of a pointer of the given pointer (vector of pointer) type.
408 Type *getIntPtrType(Type *) const;
410 /// \brief Returns the smallest integer type with size at least as big as
412 Type *getSmallestLegalIntType(LLVMContext &C, unsigned Width = 0) const;
414 /// \brief Returns the largest legal integer type, or null if none are set.
415 Type *getLargestLegalIntType(LLVMContext &C) const {
416 unsigned LargestSize = getLargestLegalIntTypeSize();
417 return (LargestSize == 0) ? nullptr : Type::getIntNTy(C, LargestSize);
420 /// \brief Returns the size of largest legal integer type size, or 0 if none
422 unsigned getLargestLegalIntTypeSize() const;
424 /// \brief Returns the offset from the beginning of the type for the specified
427 /// This is used to implement getelementptr.
428 uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
430 /// \brief Returns a StructLayout object, indicating the alignment of the
431 /// struct, its size, and the offsets of its fields.
433 /// Note that this information is lazily cached.
434 const StructLayout *getStructLayout(StructType *Ty) const;
436 /// \brief Returns the preferred alignment of the specified global.
438 /// This includes an explicitly requested alignment (if the global has one).
439 unsigned getPreferredAlignment(const GlobalVariable *GV) const;
441 /// \brief Returns the preferred alignment of the specified global, returned
444 /// This includes an explicitly requested alignment (if the global has one).
445 unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
448 inline DataLayout *unwrap(LLVMTargetDataRef P) {
449 return reinterpret_cast<DataLayout*>(P);
452 inline LLVMTargetDataRef wrap(const DataLayout *P) {
453 return reinterpret_cast<LLVMTargetDataRef>(const_cast<DataLayout*>(P));
456 class DataLayoutPass : public ImmutablePass {
460 /// This has to exist, because this is a pass, but it should never be used.
464 const DataLayout &getDataLayout() const { return DL; }
466 static char ID; // Pass identification, replacement for typeid
468 bool doFinalization(Module &M) override;
469 bool doInitialization(Module &M) override;
472 /// Used to lazily calculate structure layout information for a target machine,
473 /// based on the DataLayout structure.
476 unsigned StructAlignment;
477 unsigned NumElements;
478 uint64_t MemberOffsets[1]; // variable sized array!
481 uint64_t getSizeInBytes() const {
485 uint64_t getSizeInBits() const {
489 unsigned getAlignment() const {
490 return StructAlignment;
493 /// \brief Given a valid byte offset into the structure, returns the structure
494 /// index that contains it.
495 unsigned getElementContainingOffset(uint64_t Offset) const;
497 uint64_t getElementOffset(unsigned Idx) const {
498 assert(Idx < NumElements && "Invalid element idx!");
499 return MemberOffsets[Idx];
502 uint64_t getElementOffsetInBits(unsigned Idx) const {
503 return getElementOffset(Idx)*8;
507 friend class DataLayout; // Only DataLayout can create this class
508 StructLayout(StructType *ST, const DataLayout &DL);
512 // The implementation of this method is provided inline as it is particularly
513 // well suited to constant folding when called on a specific Type subclass.
514 inline uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const {
515 assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
516 switch (Ty->getTypeID()) {
517 case Type::LabelTyID:
518 return getPointerSizeInBits(0);
519 case Type::PointerTyID:
520 return getPointerSizeInBits(Ty->getPointerAddressSpace());
521 case Type::ArrayTyID: {
522 ArrayType *ATy = cast<ArrayType>(Ty);
523 return ATy->getNumElements() *
524 getTypeAllocSizeInBits(ATy->getElementType());
526 case Type::StructTyID:
527 // Get the layout annotation... which is lazily created on demand.
528 return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
529 case Type::IntegerTyID:
530 return Ty->getIntegerBitWidth();
533 case Type::FloatTyID:
535 case Type::DoubleTyID:
536 case Type::X86_MMXTyID:
538 case Type::PPC_FP128TyID:
539 case Type::FP128TyID:
541 // In memory objects this is always aligned to a higher boundary, but
542 // only 80 bits contain information.
543 case Type::X86_FP80TyID:
545 case Type::VectorTyID: {
546 VectorType *VTy = cast<VectorType>(Ty);
547 return VTy->getNumElements() * getTypeSizeInBits(VTy->getElementType());
550 llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
554 } // End llvm namespace