1 //===-- llvm/Attributes.h - Container for Attributes ------------*- 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 //===----------------------------------------------------------------------===//
11 /// \brief This file contains the simple types necessary to represent the
12 /// attributes associated with functions and their calls.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_IR_ATTRIBUTES_H
17 #define LLVM_IR_ATTRIBUTES_H
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/FoldingSet.h"
21 #include "llvm/Support/Compiler.h"
22 #include "llvm/Support/PointerLikeTypeTraits.h"
32 class AttributeSetImpl;
33 class AttributeSetNode;
35 template<typename T> struct DenseMapInfo;
39 //===----------------------------------------------------------------------===//
41 /// \brief Functions, function parameters, and return types can have attributes
42 /// to indicate how they should be treated by optimizations and code
43 /// generation. This class represents one of those attributes. It's light-weight
44 /// and should be passed around by-value.
47 /// This enumeration lists the attributes that can be associated with
48 /// parameters, function results, or the function itself.
50 /// Note: The `uwtable' attribute is about the ABI or the user mandating an
51 /// entry in the unwind table. The `nounwind' attribute is about an exception
52 /// passing by the function.
54 /// In a theoretical system that uses tables for profiling and SjLj for
55 /// exceptions, they would be fully independent. In a normal system that uses
56 /// tables for both, the semantics are:
58 /// nil = Needs an entry because an exception might pass by.
59 /// nounwind = No need for an entry
60 /// uwtable = Needs an entry because the ABI says so and because
61 /// an exception might pass by.
62 /// uwtable + nounwind = Needs an entry because the ABI says so.
65 // IR-Level Attributes
66 None, ///< No attributes have been set
67 Alignment, ///< Alignment of parameter (5 bits)
68 ///< stored as log2 of alignment with +1 bias
69 ///< 0 means unaligned (different from align(1))
70 AlwaysInline, ///< inline=always
71 Builtin, ///< Callee is recognized as a builtin, despite
72 ///< nobuiltin attribute on its declaration.
73 ByVal, ///< Pass structure by value
74 InAlloca, ///< Pass structure in an alloca
75 Cold, ///< Marks function as being in a cold path.
76 Convergent, ///< Can only be moved to control-equivalent blocks
77 InlineHint, ///< Source said inlining was desirable
78 InReg, ///< Force argument to be passed in register
79 JumpTable, ///< Build jump-instruction tables and replace refs.
80 MinSize, ///< Function must be optimized for size first
81 Naked, ///< Naked function
82 Nest, ///< Nested function static chain
83 NoAlias, ///< Considered to not alias after call
84 NoBuiltin, ///< Callee isn't recognized as a builtin
85 NoCapture, ///< Function creates no aliases of pointer
86 NoDuplicate, ///< Call cannot be duplicated
87 NoImplicitFloat, ///< Disable implicit floating point insts
88 NoInline, ///< inline=never
89 NonLazyBind, ///< Function is called early and/or
90 ///< often, so lazy binding isn't worthwhile
91 NonNull, ///< Pointer is known to be not null
92 Dereferenceable, ///< Pointer is known to be dereferenceable
93 DereferenceableOrNull, ///< Pointer is either null or dereferenceable
94 NoRedZone, ///< Disable redzone
95 NoReturn, ///< Mark the function as not returning
96 NoUnwind, ///< Function doesn't unwind stack
97 OptimizeForSize, ///< opt_size
98 OptimizeNone, ///< Function must not be optimized.
99 ReadNone, ///< Function does not access memory
100 ReadOnly, ///< Function only reads from memory
101 Returned, ///< Return value is always equal to this argument
102 ReturnsTwice, ///< Function can return twice
103 SExt, ///< Sign extended before/after call
104 StackAlignment, ///< Alignment of stack for function (3 bits)
105 ///< stored as log2 of alignment with +1 bias 0
106 ///< means unaligned (different from
108 StackProtect, ///< Stack protection.
109 StackProtectReq, ///< Stack protection required.
110 StackProtectStrong, ///< Strong Stack protection.
111 SafeStack, ///< Safe Stack protection.
112 StructRet, ///< Hidden pointer to structure to return
113 SanitizeAddress, ///< AddressSanitizer is on.
114 SanitizeThread, ///< ThreadSanitizer is on.
115 SanitizeMemory, ///< MemorySanitizer is on.
116 UWTable, ///< Function must be in a unwind table
117 ZExt, ///< Zero extended before/after call
119 EndAttrKinds ///< Sentinal value useful for loops
122 AttributeImpl *pImpl;
123 Attribute(AttributeImpl *A) : pImpl(A) {}
125 Attribute() : pImpl(nullptr) {}
127 //===--------------------------------------------------------------------===//
128 // Attribute Construction
129 //===--------------------------------------------------------------------===//
131 /// \brief Return a uniquified Attribute object.
132 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
133 static Attribute get(LLVMContext &Context, StringRef Kind,
134 StringRef Val = StringRef());
136 /// \brief Return a uniquified Attribute object that has the specific
138 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
139 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
140 static Attribute getWithDereferenceableBytes(LLVMContext &Context,
142 static Attribute getWithDereferenceableOrNullBytes(LLVMContext &Context,
145 //===--------------------------------------------------------------------===//
146 // Attribute Accessors
147 //===--------------------------------------------------------------------===//
149 /// \brief Return true if the attribute is an Attribute::AttrKind type.
150 bool isEnumAttribute() const;
152 /// \brief Return true if the attribute is an integer attribute.
153 bool isIntAttribute() const;
155 /// \brief Return true if the attribute is a string (target-dependent)
157 bool isStringAttribute() const;
159 /// \brief Return true if the attribute is present.
160 bool hasAttribute(AttrKind Val) const;
162 /// \brief Return true if the target-dependent attribute is present.
163 bool hasAttribute(StringRef Val) const;
165 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This
166 /// requires the attribute to be an enum or alignment attribute.
167 Attribute::AttrKind getKindAsEnum() const;
169 /// \brief Return the attribute's value as an integer. This requires that the
170 /// attribute be an alignment attribute.
171 uint64_t getValueAsInt() const;
173 /// \brief Return the attribute's kind as a string. This requires the
174 /// attribute to be a string attribute.
175 StringRef getKindAsString() const;
177 /// \brief Return the attribute's value as a string. This requires the
178 /// attribute to be a string attribute.
179 StringRef getValueAsString() const;
181 /// \brief Returns the alignment field of an attribute as a byte alignment
183 unsigned getAlignment() const;
185 /// \brief Returns the stack alignment field of an attribute as a byte
187 unsigned getStackAlignment() const;
189 /// \brief Returns the number of dereferenceable bytes from the
190 /// dereferenceable attribute (or zero if unknown).
191 uint64_t getDereferenceableBytes() const;
193 /// \brief Returns the number of dereferenceable_or_null bytes from the
194 /// dereferenceable_or_null attribute (or zero if unknown).
195 uint64_t getDereferenceableOrNullBytes() const;
197 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
198 /// is, presumably, for writing out the mnemonics for the assembly writer.
199 std::string getAsString(bool InAttrGrp = false) const;
201 /// \brief Equality and non-equality operators.
202 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
203 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
205 /// \brief Less-than operator. Useful for sorting the attributes list.
206 bool operator<(Attribute A) const;
208 void Profile(FoldingSetNodeID &ID) const {
209 ID.AddPointer(pImpl);
213 //===----------------------------------------------------------------------===//
215 /// \brief This class holds the attributes for a function, its return value, and
216 /// its parameters. You access the attributes for each of them via an index into
217 /// the AttributeSet object. The function attributes are at index
218 /// `AttributeSet::FunctionIndex', the return value is at index
219 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at
223 enum AttrIndex : unsigned {
228 friend class AttrBuilder;
229 friend class AttributeSetImpl;
230 template <typename Ty> friend struct DenseMapInfo;
232 /// \brief The attributes that we are managing. This can be null to represent
233 /// the empty attributes list.
234 AttributeSetImpl *pImpl;
236 /// \brief The attributes for the specified index are returned.
237 AttributeSetNode *getAttributes(unsigned Index) const;
239 /// \brief Create an AttributeSet with the specified parameters in it.
240 static AttributeSet get(LLVMContext &C,
241 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
242 static AttributeSet get(LLVMContext &C,
243 ArrayRef<std::pair<unsigned,
244 AttributeSetNode*> > Attrs);
246 static AttributeSet getImpl(LLVMContext &C,
247 ArrayRef<std::pair<unsigned,
248 AttributeSetNode*> > Attrs);
251 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
253 AttributeSet() : pImpl(nullptr) {}
255 //===--------------------------------------------------------------------===//
256 // AttributeSet Construction and Mutation
257 //===--------------------------------------------------------------------===//
259 /// \brief Return an AttributeSet with the specified parameters in it.
260 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
261 static AttributeSet get(LLVMContext &C, unsigned Index,
262 ArrayRef<Attribute::AttrKind> Kind);
263 static AttributeSet get(LLVMContext &C, unsigned Index, const AttrBuilder &B);
265 /// \brief Add an attribute to the attribute set at the given index. Because
266 /// attribute sets are immutable, this returns a new set.
267 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
268 Attribute::AttrKind Attr) const;
270 /// \brief Add an attribute to the attribute set at the given index. Because
271 /// attribute sets are immutable, this returns a new set.
272 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
273 StringRef Kind) const;
274 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
275 StringRef Kind, StringRef Value) const;
277 /// \brief Add attributes to the attribute set at the given index. Because
278 /// attribute sets are immutable, this returns a new set.
279 AttributeSet addAttributes(LLVMContext &C, unsigned Index,
280 AttributeSet Attrs) const;
282 /// \brief Remove the specified attribute at the specified index from this
283 /// attribute list. Because attribute lists are immutable, this returns the
285 AttributeSet removeAttribute(LLVMContext &C, unsigned Index,
286 Attribute::AttrKind Attr) const;
288 /// \brief Remove the specified attributes at the specified index from this
289 /// attribute list. Because attribute lists are immutable, this returns the
291 AttributeSet removeAttributes(LLVMContext &C, unsigned Index,
292 AttributeSet Attrs) const;
294 /// \brief Remove the specified attributes at the specified index from this
295 /// attribute list. Because attribute lists are immutable, this returns the
297 AttributeSet removeAttributes(LLVMContext &C, unsigned Index,
298 const AttrBuilder &Attrs) const;
300 /// \brief Add the dereferenceable attribute to the attribute set at the given
301 /// index. Because attribute sets are immutable, this returns a new set.
302 AttributeSet addDereferenceableAttr(LLVMContext &C, unsigned Index,
303 uint64_t Bytes) const;
305 /// \brief Add the dereferenceable_or_null attribute to the attribute set at
306 /// the given index. Because attribute sets are immutable, this returns a new
308 AttributeSet addDereferenceableOrNullAttr(LLVMContext &C, unsigned Index,
309 uint64_t Bytes) const;
311 //===--------------------------------------------------------------------===//
312 // AttributeSet Accessors
313 //===--------------------------------------------------------------------===//
315 /// \brief Retrieve the LLVM context.
316 LLVMContext &getContext() const;
318 /// \brief The attributes for the specified index are returned.
319 AttributeSet getParamAttributes(unsigned Index) const;
321 /// \brief The attributes for the ret value are returned.
322 AttributeSet getRetAttributes() const;
324 /// \brief The function attributes are returned.
325 AttributeSet getFnAttributes() const;
327 /// \brief Return true if the attribute exists at the given index.
328 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
330 /// \brief Return true if the attribute exists at the given index.
331 bool hasAttribute(unsigned Index, StringRef Kind) const;
333 /// \brief Return true if attribute exists at the given index.
334 bool hasAttributes(unsigned Index) const;
336 /// \brief Return true if the specified attribute is set for at least one
337 /// parameter or for the return value.
338 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
340 /// \brief Return the attribute object that exists at the given index.
341 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const;
343 /// \brief Return the attribute object that exists at the given index.
344 Attribute getAttribute(unsigned Index, StringRef Kind) const;
346 /// \brief Return the alignment for the specified function parameter.
347 unsigned getParamAlignment(unsigned Index) const;
349 /// \brief Get the stack alignment.
350 unsigned getStackAlignment(unsigned Index) const;
352 /// \brief Get the number of dereferenceable bytes (or zero if unknown).
353 uint64_t getDereferenceableBytes(unsigned Index) const;
355 /// \brief Get the number of dereferenceable_or_null bytes (or zero if
357 uint64_t getDereferenceableOrNullBytes(unsigned Index) const;
359 /// \brief Return the attributes at the index as a string.
360 std::string getAsString(unsigned Index, bool InAttrGrp = false) const;
362 typedef ArrayRef<Attribute>::iterator iterator;
364 iterator begin(unsigned Slot) const;
365 iterator end(unsigned Slot) const;
367 /// operator==/!= - Provide equality predicates.
368 bool operator==(const AttributeSet &RHS) const {
369 return pImpl == RHS.pImpl;
371 bool operator!=(const AttributeSet &RHS) const {
372 return pImpl != RHS.pImpl;
375 //===--------------------------------------------------------------------===//
376 // AttributeSet Introspection
377 //===--------------------------------------------------------------------===//
379 // FIXME: Remove this.
380 uint64_t Raw(unsigned Index) const;
382 /// \brief Return a raw pointer that uniquely identifies this attribute list.
383 void *getRawPointer() const {
387 /// \brief Return true if there are no attributes.
388 bool isEmpty() const {
389 return getNumSlots() == 0;
392 /// \brief Return the number of slots used in this attribute list. This is
393 /// the number of arguments that have an attribute set on them (including the
394 /// function itself).
395 unsigned getNumSlots() const;
397 /// \brief Return the index for the given slot.
398 unsigned getSlotIndex(unsigned Slot) const;
400 /// \brief Return the attributes at the given slot.
401 AttributeSet getSlotAttributes(unsigned Slot) const;
406 //===----------------------------------------------------------------------===//
408 /// \brief Provide DenseMapInfo for AttributeSet.
409 template<> struct DenseMapInfo<AttributeSet> {
410 static inline AttributeSet getEmptyKey() {
411 uintptr_t Val = static_cast<uintptr_t>(-1);
412 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
413 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
415 static inline AttributeSet getTombstoneKey() {
416 uintptr_t Val = static_cast<uintptr_t>(-2);
417 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
418 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
420 static unsigned getHashValue(AttributeSet AS) {
421 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
422 (unsigned((uintptr_t)AS.pImpl) >> 9);
424 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
427 //===----------------------------------------------------------------------===//
429 /// \brief This class is used in conjunction with the Attribute::get method to
430 /// create an Attribute object. The object itself is uniquified. The Builder's
431 /// value, however, is not. So this can be used as a quick way to test for
432 /// equality, presence of attributes, etc.
434 std::bitset<Attribute::EndAttrKinds> Attrs;
435 std::map<std::string, std::string> TargetDepAttrs;
437 uint64_t StackAlignment;
439 uint64_t DerefOrNullBytes;
442 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0),
443 DerefOrNullBytes(0) {}
444 explicit AttrBuilder(uint64_t Val)
445 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0),
446 DerefOrNullBytes(0) {
449 AttrBuilder(const Attribute &A)
450 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0),
451 DerefOrNullBytes(0) {
454 AttrBuilder(AttributeSet AS, unsigned Idx);
458 /// \brief Add an attribute to the builder.
459 AttrBuilder &addAttribute(Attribute::AttrKind Val);
461 /// \brief Add the Attribute object to the builder.
462 AttrBuilder &addAttribute(Attribute A);
464 /// \brief Add the target-dependent attribute to the builder.
465 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef());
467 /// \brief Remove an attribute from the builder.
468 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
470 /// \brief Remove the attributes from the builder.
471 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
473 /// \brief Remove the target-dependent attribute to the builder.
474 AttrBuilder &removeAttribute(StringRef A);
476 /// \brief Add the attributes from the builder.
477 AttrBuilder &merge(const AttrBuilder &B);
479 /// \brief Remove the attributes from the builder.
480 AttrBuilder &remove(const AttrBuilder &B);
482 /// \brief Return true if the builder has any attribute that's in the
483 /// specified builder.
484 bool overlaps(const AttrBuilder &B) const;
486 /// \brief Return true if the builder has the specified attribute.
487 bool contains(Attribute::AttrKind A) const {
488 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!");
492 /// \brief Return true if the builder has the specified target-dependent
494 bool contains(StringRef A) const;
496 /// \brief Return true if the builder has IR-level attributes.
497 bool hasAttributes() const;
499 /// \brief Return true if the builder has any attribute that's in the
500 /// specified attribute.
501 bool hasAttributes(AttributeSet A, uint64_t Index) const;
503 /// \brief Return true if the builder has an alignment attribute.
504 bool hasAlignmentAttr() const;
506 /// \brief Retrieve the alignment attribute, if it exists.
507 uint64_t getAlignment() const { return Alignment; }
509 /// \brief Retrieve the stack alignment attribute, if it exists.
510 uint64_t getStackAlignment() const { return StackAlignment; }
512 /// \brief Retrieve the number of dereferenceable bytes, if the dereferenceable
513 /// attribute exists (zero is returned otherwise).
514 uint64_t getDereferenceableBytes() const { return DerefBytes; }
516 /// \brief Retrieve the number of dereferenceable_or_null bytes, if the
517 /// dereferenceable_or_null attribute exists (zero is returned otherwise).
518 uint64_t getDereferenceableOrNullBytes() const { return DerefOrNullBytes; }
520 /// \brief This turns an int alignment (which must be a power of 2) into the
521 /// form used internally in Attribute.
522 AttrBuilder &addAlignmentAttr(unsigned Align);
524 /// \brief This turns an int stack alignment (which must be a power of 2) into
525 /// the form used internally in Attribute.
526 AttrBuilder &addStackAlignmentAttr(unsigned Align);
528 /// \brief This turns the number of dereferenceable bytes into the form used
529 /// internally in Attribute.
530 AttrBuilder &addDereferenceableAttr(uint64_t Bytes);
532 /// \brief This turns the number of dereferenceable_or_null bytes into the
533 /// form used internally in Attribute.
534 AttrBuilder &addDereferenceableOrNullAttr(uint64_t Bytes);
536 /// \brief Return true if the builder contains no target-independent
538 bool empty() const { return Attrs.none(); }
540 // Iterators for target-dependent attributes.
541 typedef std::pair<std::string, std::string> td_type;
542 typedef std::map<std::string, std::string>::iterator td_iterator;
543 typedef std::map<std::string, std::string>::const_iterator td_const_iterator;
544 typedef llvm::iterator_range<td_iterator> td_range;
545 typedef llvm::iterator_range<td_const_iterator> td_const_range;
547 td_iterator td_begin() { return TargetDepAttrs.begin(); }
548 td_iterator td_end() { return TargetDepAttrs.end(); }
550 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
551 td_const_iterator td_end() const { return TargetDepAttrs.end(); }
553 td_range td_attrs() { return td_range(td_begin(), td_end()); }
554 td_const_range td_attrs() const {
555 return td_const_range(td_begin(), td_end());
558 bool td_empty() const { return TargetDepAttrs.empty(); }
560 bool operator==(const AttrBuilder &B);
561 bool operator!=(const AttrBuilder &B) {
562 return !(*this == B);
565 // FIXME: Remove this in 4.0.
567 /// \brief Add the raw value to the internal representation.
568 AttrBuilder &addRawValue(uint64_t Val);
571 namespace AttributeFuncs {
573 /// \brief Which attributes cannot be applied to a type.
574 AttrBuilder typeIncompatible(const Type *Ty);
576 } // end AttributeFuncs namespace
578 } // end llvm namespace