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 InlineHint, ///< Source said inlining was desirable
77 InReg, ///< Force argument to be passed in register
78 JumpTable, ///< Build jump-instruction tables and replace refs.
79 MinSize, ///< Function must be optimized for size first
80 Naked, ///< Naked function
81 Nest, ///< Nested function static chain
82 NoAlias, ///< Considered to not alias after call
83 NoBuiltin, ///< Callee isn't recognized as a builtin
84 NoCapture, ///< Function creates no aliases of pointer
85 NoDuplicate, ///< Call cannot be duplicated
86 NoImplicitFloat, ///< Disable implicit floating point insts
87 NoInline, ///< inline=never
88 NonLazyBind, ///< Function is called early and/or
89 ///< often, so lazy binding isn't worthwhile
90 NonNull, ///< Pointer is known to be not null
91 Dereferenceable, ///< Pointer is known to be dereferenceable
92 NoRedZone, ///< Disable redzone
93 NoReturn, ///< Mark the function as not returning
94 NoUnwind, ///< Function doesn't unwind stack
95 OptimizeForSize, ///< opt_size
96 OptimizeNone, ///< Function must not be optimized.
97 ReadNone, ///< Function does not access memory
98 ReadOnly, ///< Function only reads from memory
99 Returned, ///< Return value is always equal to this argument
100 ReturnsTwice, ///< Function can return twice
101 SExt, ///< Sign extended before/after call
102 StackAlignment, ///< Alignment of stack for function (3 bits)
103 ///< stored as log2 of alignment with +1 bias 0
104 ///< means unaligned (different from
106 StackProtect, ///< Stack protection.
107 StackProtectReq, ///< Stack protection required.
108 StackProtectStrong, ///< Strong Stack protection.
109 StructRet, ///< Hidden pointer to structure to return
110 SanitizeAddress, ///< AddressSanitizer is on.
111 SanitizeThread, ///< ThreadSanitizer is on.
112 SanitizeMemory, ///< MemorySanitizer is on.
113 UWTable, ///< Function must be in a unwind table
114 ZExt, ///< Zero extended before/after call
116 EndAttrKinds ///< Sentinal value useful for loops
119 AttributeImpl *pImpl;
120 Attribute(AttributeImpl *A) : pImpl(A) {}
122 Attribute() : pImpl(nullptr) {}
124 //===--------------------------------------------------------------------===//
125 // Attribute Construction
126 //===--------------------------------------------------------------------===//
128 /// \brief Return a uniquified Attribute object.
129 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
130 static Attribute get(LLVMContext &Context, StringRef Kind,
131 StringRef Val = StringRef());
133 /// \brief Return a uniquified Attribute object that has the specific
135 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
136 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
137 static Attribute getWithDereferenceableBytes(LLVMContext &Context,
140 //===--------------------------------------------------------------------===//
141 // Attribute Accessors
142 //===--------------------------------------------------------------------===//
144 /// \brief Return true if the attribute is an Attribute::AttrKind type.
145 bool isEnumAttribute() const;
147 /// \brief Return true if the attribute is an integer attribute.
148 bool isIntAttribute() const;
150 /// \brief Return true if the attribute is a string (target-dependent)
152 bool isStringAttribute() const;
154 /// \brief Return true if the attribute is present.
155 bool hasAttribute(AttrKind Val) const;
157 /// \brief Return true if the target-dependent attribute is present.
158 bool hasAttribute(StringRef Val) const;
160 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This
161 /// requires the attribute to be an enum or alignment attribute.
162 Attribute::AttrKind getKindAsEnum() const;
164 /// \brief Return the attribute's value as an integer. This requires that the
165 /// attribute be an alignment attribute.
166 uint64_t getValueAsInt() const;
168 /// \brief Return the attribute's kind as a string. This requires the
169 /// attribute to be a string attribute.
170 StringRef getKindAsString() const;
172 /// \brief Return the attribute's value as a string. This requires the
173 /// attribute to be a string attribute.
174 StringRef getValueAsString() const;
176 /// \brief Returns the alignment field of an attribute as a byte alignment
178 unsigned getAlignment() const;
180 /// \brief Returns the stack alignment field of an attribute as a byte
182 unsigned getStackAlignment() const;
184 /// \brief Returns the number of dereferenceable bytes from the
185 /// dereferenceable attribute (or zero if unknown).
186 uint64_t getDereferenceableBytes() const;
188 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
189 /// is, presumably, for writing out the mnemonics for the assembly writer.
190 std::string getAsString(bool InAttrGrp = false) const;
192 /// \brief Equality and non-equality operators.
193 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
194 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
196 /// \brief Less-than operator. Useful for sorting the attributes list.
197 bool operator<(Attribute A) const;
199 void Profile(FoldingSetNodeID &ID) const {
200 ID.AddPointer(pImpl);
204 //===----------------------------------------------------------------------===//
206 /// \brief This class holds the attributes for a function, its return value, and
207 /// its parameters. You access the attributes for each of them via an index into
208 /// the AttributeSet object. The function attributes are at index
209 /// `AttributeSet::FunctionIndex', the return value is at index
210 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at
214 enum AttrIndex : unsigned {
219 friend class AttrBuilder;
220 friend class AttributeSetImpl;
221 template <typename Ty> friend struct DenseMapInfo;
223 /// \brief The attributes that we are managing. This can be null to represent
224 /// the empty attributes list.
225 AttributeSetImpl *pImpl;
227 /// \brief The attributes for the specified index are returned.
228 AttributeSetNode *getAttributes(unsigned Index) const;
230 /// \brief Create an AttributeSet with the specified parameters in it.
231 static AttributeSet get(LLVMContext &C,
232 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
233 static AttributeSet get(LLVMContext &C,
234 ArrayRef<std::pair<unsigned,
235 AttributeSetNode*> > Attrs);
237 static AttributeSet getImpl(LLVMContext &C,
238 ArrayRef<std::pair<unsigned,
239 AttributeSetNode*> > Attrs);
242 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
244 AttributeSet() : pImpl(nullptr) {}
246 //===--------------------------------------------------------------------===//
247 // AttributeSet Construction and Mutation
248 //===--------------------------------------------------------------------===//
250 /// \brief Return an AttributeSet with the specified parameters in it.
251 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
252 static AttributeSet get(LLVMContext &C, unsigned Index,
253 ArrayRef<Attribute::AttrKind> Kind);
254 static AttributeSet get(LLVMContext &C, unsigned Index, const AttrBuilder &B);
256 /// \brief Add an attribute to the attribute set at the given index. Since
257 /// attribute sets are immutable, this returns a new set.
258 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
259 Attribute::AttrKind Attr) const;
261 /// \brief Add an attribute to the attribute set at the given index. Since
262 /// attribute sets are immutable, this returns a new set.
263 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
264 StringRef Kind) const;
265 AttributeSet addAttribute(LLVMContext &C, unsigned Index,
266 StringRef Kind, StringRef Value) const;
268 /// \brief Add attributes to the attribute set at the given index. Since
269 /// attribute sets are immutable, this returns a new set.
270 AttributeSet addAttributes(LLVMContext &C, unsigned Index,
271 AttributeSet Attrs) const;
273 /// \brief Remove the specified attribute at the specified index from this
274 /// attribute list. Since attribute lists are immutable, this returns the new
276 AttributeSet removeAttribute(LLVMContext &C, unsigned Index,
277 Attribute::AttrKind Attr) const;
279 /// \brief Remove the specified attributes at the specified index from this
280 /// attribute list. Since attribute lists are immutable, this returns the new
282 AttributeSet removeAttributes(LLVMContext &C, unsigned Index,
283 AttributeSet Attrs) const;
285 /// \brief Add the dereferenceable attribute to the attribute set at the given
286 /// index. Since attribute sets are immutable, this returns a new set.
287 AttributeSet addDereferenceableAttr(LLVMContext &C, unsigned Index,
288 uint64_t Bytes) const;
290 //===--------------------------------------------------------------------===//
291 // AttributeSet Accessors
292 //===--------------------------------------------------------------------===//
294 /// \brief Retrieve the LLVM context.
295 LLVMContext &getContext() const;
297 /// \brief The attributes for the specified index are returned.
298 AttributeSet getParamAttributes(unsigned Index) const;
300 /// \brief The attributes for the ret value are returned.
301 AttributeSet getRetAttributes() const;
303 /// \brief The function attributes are returned.
304 AttributeSet getFnAttributes() const;
306 /// \brief Return true if the attribute exists at the given index.
307 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
309 /// \brief Return true if the attribute exists at the given index.
310 bool hasAttribute(unsigned Index, StringRef Kind) const;
312 /// \brief Return true if attribute exists at the given index.
313 bool hasAttributes(unsigned Index) const;
315 /// \brief Return true if the specified attribute is set for at least one
316 /// parameter or for the return value.
317 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
319 /// \brief Return the attribute object that exists at the given index.
320 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const;
322 /// \brief Return the attribute object that exists at the given index.
323 Attribute getAttribute(unsigned Index, StringRef Kind) const;
325 /// \brief Return the alignment for the specified function parameter.
326 unsigned getParamAlignment(unsigned Index) const;
328 /// \brief Get the stack alignment.
329 unsigned getStackAlignment(unsigned Index) const;
331 /// \brief Get the number of dereferenceable bytes (or zero if unknown).
332 uint64_t getDereferenceableBytes(unsigned Index) const;
334 /// \brief Return the attributes at the index as a string.
335 std::string getAsString(unsigned Index, bool InAttrGrp = false) const;
337 typedef ArrayRef<Attribute>::iterator iterator;
339 iterator begin(unsigned Slot) const;
340 iterator end(unsigned Slot) const;
342 /// operator==/!= - Provide equality predicates.
343 bool operator==(const AttributeSet &RHS) const {
344 return pImpl == RHS.pImpl;
346 bool operator!=(const AttributeSet &RHS) const {
347 return pImpl != RHS.pImpl;
350 //===--------------------------------------------------------------------===//
351 // AttributeSet Introspection
352 //===--------------------------------------------------------------------===//
354 // FIXME: Remove this.
355 uint64_t Raw(unsigned Index) const;
357 /// \brief Return a raw pointer that uniquely identifies this attribute list.
358 void *getRawPointer() const {
362 /// \brief Return true if there are no attributes.
363 bool isEmpty() const {
364 return getNumSlots() == 0;
367 /// \brief Return the number of slots used in this attribute list. This is
368 /// the number of arguments that have an attribute set on them (including the
369 /// function itself).
370 unsigned getNumSlots() const;
372 /// \brief Return the index for the given slot.
373 unsigned getSlotIndex(unsigned Slot) const;
375 /// \brief Return the attributes at the given slot.
376 AttributeSet getSlotAttributes(unsigned Slot) const;
381 //===----------------------------------------------------------------------===//
383 /// \brief Provide DenseMapInfo for AttributeSet.
384 template<> struct DenseMapInfo<AttributeSet> {
385 static inline AttributeSet getEmptyKey() {
386 uintptr_t Val = static_cast<uintptr_t>(-1);
387 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
388 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
390 static inline AttributeSet getTombstoneKey() {
391 uintptr_t Val = static_cast<uintptr_t>(-2);
392 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
393 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
395 static unsigned getHashValue(AttributeSet AS) {
396 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
397 (unsigned((uintptr_t)AS.pImpl) >> 9);
399 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
402 //===----------------------------------------------------------------------===//
404 /// \brief This class is used in conjunction with the Attribute::get method to
405 /// create an Attribute object. The object itself is uniquified. The Builder's
406 /// value, however, is not. So this can be used as a quick way to test for
407 /// equality, presence of attributes, etc.
409 std::bitset<Attribute::EndAttrKinds> Attrs;
410 std::map<std::string, std::string> TargetDepAttrs;
412 uint64_t StackAlignment;
415 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {}
416 explicit AttrBuilder(uint64_t Val)
417 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {
420 AttrBuilder(const Attribute &A)
421 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {
424 AttrBuilder(AttributeSet AS, unsigned Idx);
428 /// \brief Add an attribute to the builder.
429 AttrBuilder &addAttribute(Attribute::AttrKind Val);
431 /// \brief Add the Attribute object to the builder.
432 AttrBuilder &addAttribute(Attribute A);
434 /// \brief Add the target-dependent attribute to the builder.
435 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef());
437 /// \brief Remove an attribute from the builder.
438 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
440 /// \brief Remove the attributes from the builder.
441 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
443 /// \brief Remove the target-dependent attribute to the builder.
444 AttrBuilder &removeAttribute(StringRef A);
446 /// \brief Add the attributes from the builder.
447 AttrBuilder &merge(const AttrBuilder &B);
449 /// \brief Return true if the builder has the specified attribute.
450 bool contains(Attribute::AttrKind A) const {
451 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!");
455 /// \brief Return true if the builder has the specified target-dependent
457 bool contains(StringRef A) const;
459 /// \brief Return true if the builder has IR-level attributes.
460 bool hasAttributes() const;
462 /// \brief Return true if the builder has any attribute that's in the
463 /// specified attribute.
464 bool hasAttributes(AttributeSet A, uint64_t Index) const;
466 /// \brief Return true if the builder has an alignment attribute.
467 bool hasAlignmentAttr() const;
469 /// \brief Retrieve the alignment attribute, if it exists.
470 uint64_t getAlignment() const { return Alignment; }
472 /// \brief Retrieve the stack alignment attribute, if it exists.
473 uint64_t getStackAlignment() const { return StackAlignment; }
475 /// \brief Retrieve the number of dereferenceable bytes, if the dereferenceable
476 /// attribute exists (zero is returned otherwise).
477 uint64_t getDereferenceableBytes() const { return DerefBytes; }
479 /// \brief This turns an int alignment (which must be a power of 2) into the
480 /// form used internally in Attribute.
481 AttrBuilder &addAlignmentAttr(unsigned Align);
483 /// \brief This turns an int stack alignment (which must be a power of 2) into
484 /// the form used internally in Attribute.
485 AttrBuilder &addStackAlignmentAttr(unsigned Align);
487 /// \brief This turns the number of dereferenceable bytes into the form used
488 /// internally in Attribute.
489 AttrBuilder &addDereferenceableAttr(uint64_t Bytes);
491 /// \brief Return true if the builder contains no target-independent
493 bool empty() const { return Attrs.none(); }
495 // Iterators for target-dependent attributes.
496 typedef std::pair<std::string, std::string> td_type;
497 typedef std::map<std::string, std::string>::iterator td_iterator;
498 typedef std::map<std::string, std::string>::const_iterator td_const_iterator;
499 typedef llvm::iterator_range<td_iterator> td_range;
500 typedef llvm::iterator_range<td_const_iterator> td_const_range;
502 td_iterator td_begin() { return TargetDepAttrs.begin(); }
503 td_iterator td_end() { return TargetDepAttrs.end(); }
505 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
506 td_const_iterator td_end() const { return TargetDepAttrs.end(); }
508 td_range td_attrs() { return td_range(td_begin(), td_end()); }
509 td_const_range td_attrs() const {
510 return td_const_range(td_begin(), td_end());
513 bool td_empty() const { return TargetDepAttrs.empty(); }
515 bool operator==(const AttrBuilder &B);
516 bool operator!=(const AttrBuilder &B) {
517 return !(*this == B);
520 // FIXME: Remove this in 4.0.
522 /// \brief Add the raw value to the internal representation.
523 AttrBuilder &addRawValue(uint64_t Val);
526 namespace AttributeFuncs {
528 /// \brief Which attributes cannot be applied to a type.
529 AttributeSet typeIncompatible(Type *Ty, uint64_t Index);
531 } // end AttributeFuncs namespace
533 } // end llvm namespace