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/DenseSet.h"
21 #include "llvm/ADT/FoldingSet.h"
22 #include "llvm/Support/MathExtras.h"
34 //===----------------------------------------------------------------------===//
36 /// \brief Functions, function parameters, and return types can have attributes
37 /// to indicate how they should be treated by optimizations and code
38 /// generation. This class represents one of those attributes. It's light-weight
39 /// and should be passed around by-value.
42 /// This enumeration lists the attributes that can be associated with
43 /// parameters, function results or the function itself.
45 /// Note: uwtable is about the ABI or the user mandating an entry in the
46 /// unwind table. The nounwind attribute is about an exception passing by the
49 /// In a theoretical system that uses tables for profiling and sjlj for
50 /// exceptions, they would be fully independent. In a normal system that uses
51 /// tables for both, the semantics are:
53 /// nil = Needs an entry because an exception might pass by.
54 /// nounwind = No need for an entry
55 /// uwtable = Needs an entry because the ABI says so and because
56 /// an exception might pass by.
57 /// uwtable + nounwind = Needs an entry because the ABI says so.
60 // IR-Level Attributes
61 None, ///< No attributes have been set
62 AddressSafety, ///< Address safety checking is on.
63 Alignment, ///< Alignment of parameter (5 bits)
64 ///< stored as log2 of alignment with +1 bias
65 ///< 0 means unaligned (different from align(1))
66 AlwaysInline, ///< inline=always
67 ByVal, ///< Pass structure by value
68 InlineHint, ///< Source said inlining was desirable
69 InReg, ///< Force argument to be passed in register
70 MinSize, ///< Function must be optimized for size first
71 Naked, ///< Naked function
72 Nest, ///< Nested function static chain
73 NoAlias, ///< Considered to not alias after call
74 NoCapture, ///< Function creates no aliases of pointer
75 NoDuplicate, ///< Call cannot be duplicated
76 NoImplicitFloat, ///< Disable implicit floating point insts
77 NoInline, ///< inline=never
78 NonLazyBind, ///< Function is called early and/or
79 ///< often, so lazy binding isn't worthwhile
80 NoRedZone, ///< Disable redzone
81 NoReturn, ///< Mark the function as not returning
82 NoUnwind, ///< Function doesn't unwind stack
83 OptimizeForSize, ///< opt_size
84 ReadNone, ///< Function does not access memory
85 ReadOnly, ///< Function only reads from memory
86 ReturnsTwice, ///< Function can return twice
87 SExt, ///< Sign extended before/after call
88 StackAlignment, ///< Alignment of stack for function (3 bits)
89 ///< stored as log2 of alignment with +1 bias 0
90 ///< means unaligned (different from
92 StackProtect, ///< Stack protection.
93 StackProtectReq, ///< Stack protection required.
94 StackProtectStrong, ///< Strong Stack protection.
95 StructRet, ///< Hidden pointer to structure to return
96 UWTable, ///< Function must be in a unwind table
97 ZExt, ///< Zero extended before/after call
99 EndAttrKinds, ///< Sentinal value useful for loops
101 AttrKindEmptyKey, ///< Empty key value for DenseMapInfo
102 AttrKindTombstoneKey ///< Tombstone key value for DenseMapInfo
105 AttributeImpl *pImpl;
106 Attribute(AttributeImpl *A) : pImpl(A) {}
108 Attribute() : pImpl(0) {}
110 /// \brief Return a uniquified Attribute object.
111 static Attribute get(LLVMContext &Context, ArrayRef<AttrKind> Kinds);
112 static Attribute get(LLVMContext &Context, AttrBuilder &B);
114 /// \brief Return a uniquified Attribute object that has the specific
116 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
117 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
119 /// \brief Return true if the attribute is present.
120 bool hasAttribute(AttrKind Val) const;
122 /// \brief Return true if attributes exist
123 bool hasAttributes() const;
125 /// \brief Returns the alignment field of an attribute as a byte alignment
127 unsigned getAlignment() const;
129 /// \brief Returns the stack alignment field of an attribute as a byte
131 unsigned getStackAlignment() const;
133 /// \brief Equality and non-equality query methods.
134 bool operator==(AttrKind K) const;
135 bool operator!=(AttrKind K) const;
137 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
138 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
140 /// \brief Less-than operator. Useful for sorting the attributes list.
141 bool operator<(Attribute A) const;
143 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
144 /// is, presumably, for writing out the mnemonics for the assembly writer.
145 std::string getAsString() const;
147 void Profile(FoldingSetNodeID &ID) const {
148 ID.AddPointer(pImpl);
151 uint64_t Raw() const;
154 //===----------------------------------------------------------------------===//
156 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
158 template<> struct DenseMapInfo<Attribute::AttrKind> {
159 static inline Attribute::AttrKind getEmptyKey() {
160 return Attribute::AttrKindEmptyKey;
162 static inline Attribute::AttrKind getTombstoneKey() {
163 return Attribute::AttrKindTombstoneKey;
165 static unsigned getHashValue(const Attribute::AttrKind &Val) {
168 static bool isEqual(const Attribute::AttrKind &LHS,
169 const Attribute::AttrKind &RHS) {
174 //===----------------------------------------------------------------------===//
175 // AttributeSet Smart Pointer
176 //===----------------------------------------------------------------------===//
179 class AttributeSetImpl;
180 class AttributeSetNode;
182 //===----------------------------------------------------------------------===//
184 /// \brief This class manages the ref count for the opaque AttributeSetImpl
185 /// object and provides accessors for it.
193 friend class AttrBuilder;
194 friend class AttributeSetImpl;
196 /// \brief The attributes that we are managing. This can be null to represent
197 /// the empty attributes list.
198 AttributeSetImpl *pImpl;
200 /// \brief The attributes for the specified index are returned. Attributes
201 /// for the result are denoted with Idx = 0.
202 Attribute getAttributes(unsigned Idx) const;
204 /// \brief Create an AttributeSet with the specified parameters in it.
205 static AttributeSet get(LLVMContext &C,
206 ArrayRef<std::pair<uint64_t, Attribute> > Attrs);
207 static AttributeSet get(LLVMContext &C,
208 ArrayRef<std::pair<uint64_t,
209 AttributeSetNode*> > Attrs);
211 static AttributeSet getImpl(LLVMContext &C,
212 ArrayRef<std::pair<uint64_t,
213 AttributeSetNode*> > Attrs);
216 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
218 AttributeSet() : pImpl(0) {}
219 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
220 const AttributeSet &operator=(const AttributeSet &RHS) {
225 //===--------------------------------------------------------------------===//
226 // Attribute List Construction and Mutation
227 //===--------------------------------------------------------------------===//
229 /// \brief Return an AttributeSet with the specified parameters in it.
230 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
231 static AttributeSet get(LLVMContext &C, unsigned Idx,
232 ArrayRef<Attribute::AttrKind> Kind);
233 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
235 /// \brief Add an attribute to the attribute set at the given index. Since
236 /// attribute sets are immutable, this returns a new set.
237 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
238 Attribute::AttrKind Attr) const;
240 /// \brief Add attributes to the attribute set at the given index. Since
241 /// attribute sets are immutable, this returns a new set.
242 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
243 AttributeSet Attrs) const;
245 /// \brief Add return attributes to this attribute set. Since attribute sets
246 /// are immutable, this returns a new set.
247 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const {
248 return addAttributes(C, ReturnIndex, Attrs);
251 /// \brief Add function attributes to this attribute set. Since attribute sets
252 /// are immutable, this returns a new set.
253 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const {
254 return addAttributes(C, FunctionIndex, Attrs);
257 /// \brief Remove the specified attribute at the specified index from this
258 /// attribute list. Since attribute lists are immutable, this returns the new
260 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
261 Attribute::AttrKind Attr) const;
263 /// \brief Remove the specified attributes at the specified index from this
264 /// attribute list. Since attribute lists are immutable, this returns the new
266 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
267 AttributeSet Attrs) const;
269 //===--------------------------------------------------------------------===//
270 // Attribute Set Accessors
271 //===--------------------------------------------------------------------===//
273 /// \brief The attributes for the specified index are returned.
274 AttributeSet getParamAttributes(unsigned Idx) const;
276 /// \brief The attributes for the ret value are returned.
277 AttributeSet getRetAttributes() const;
279 /// \brief The function attributes are returned.
280 AttributeSet getFnAttributes() const;
282 /// \brief Return true if the attribute exists at the given index.
283 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
285 /// \brief Return true if attribute exists at the given index.
286 bool hasAttributes(unsigned Index) const;
288 /// \brief Return the alignment for the specified function parameter.
289 unsigned getParamAlignment(unsigned Idx) const;
291 /// \brief Get the stack alignment.
292 unsigned getStackAlignment(unsigned Index) const;
294 /// \brief Return the attributes at the index as a string.
295 std::string getAsString(unsigned Index) const;
297 uint64_t Raw(unsigned Index) const;
299 /// \brief Return true if the specified attribute is set for at least one
300 /// parameter or for the return value.
301 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
303 /// operator==/!= - Provide equality predicates.
304 bool operator==(const AttributeSet &RHS) const {
305 return pImpl == RHS.pImpl;
307 bool operator!=(const AttributeSet &RHS) const {
308 return pImpl != RHS.pImpl;
311 //===--------------------------------------------------------------------===//
312 // Attribute List Introspection
313 //===--------------------------------------------------------------------===//
315 /// \brief Return a raw pointer that uniquely identifies this attribute list.
316 void *getRawPointer() const {
320 // Attributes are stored as a dense set of slots, where there is one slot for
321 // each argument that has an attribute. This allows walking over the dense
322 // set instead of walking the sparse list of attributes.
324 /// \brief Return true if there are no attributes.
325 bool isEmpty() const {
329 /// \brief Return the number of slots used in this attribute list. This is
330 /// the number of arguments that have an attribute set on them (including the
331 /// function itself).
332 unsigned getNumSlots() const;
334 /// \brief Return the index for the given slot.
335 uint64_t getSlotIndex(unsigned Slot) const;
337 /// \brief Return the attributes at the given slot.
338 AttributeSet getSlotAttributes(unsigned Slot) const;
343 //===----------------------------------------------------------------------===//
345 /// \brief This class is used in conjunction with the Attribute::get method to
346 /// create an Attribute object. The object itself is uniquified. The Builder's
347 /// value, however, is not. So this can be used as a quick way to test for
348 /// equality, presence of attributes, etc.
350 DenseSet<Attribute::AttrKind> Attrs;
352 uint64_t StackAlignment;
354 AttrBuilder() : Alignment(0), StackAlignment(0) {}
355 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
358 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
361 AttrBuilder(AttributeSet AS, unsigned Idx);
365 /// \brief Add an attribute to the builder.
366 AttrBuilder &addAttribute(Attribute::AttrKind Val);
368 /// \brief Remove an attribute from the builder.
369 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
371 /// \brief Add the attributes to the builder.
372 AttrBuilder &addAttributes(Attribute A);
374 /// \brief Remove the attributes from the builder.
375 AttrBuilder &removeAttributes(Attribute A);
377 /// \brief Add the attributes to the builder.
378 AttrBuilder &addAttributes(AttributeSet A);
380 /// \brief Return true if the builder has the specified attribute.
381 bool contains(Attribute::AttrKind A) const;
383 /// \brief Return true if the builder has IR-level attributes.
384 bool hasAttributes() const;
386 /// \brief Return true if the builder has any attribute that's in the
387 /// specified attribute.
388 bool hasAttributes(const Attribute &A) const;
390 /// \brief Return true if the builder has an alignment attribute.
391 bool hasAlignmentAttr() const;
393 /// \brief Retrieve the alignment attribute, if it exists.
394 uint64_t getAlignment() const { return Alignment; }
396 /// \brief Retrieve the stack alignment attribute, if it exists.
397 uint64_t getStackAlignment() const { return StackAlignment; }
399 /// \brief This turns an int alignment (which must be a power of 2) into the
400 /// form used internally in Attribute.
401 AttrBuilder &addAlignmentAttr(unsigned Align);
403 /// \brief This turns an int stack alignment (which must be a power of 2) into
404 /// the form used internally in Attribute.
405 AttrBuilder &addStackAlignmentAttr(unsigned Align);
407 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
408 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
410 iterator begin() { return Attrs.begin(); }
411 iterator end() { return Attrs.end(); }
413 const_iterator begin() const { return Attrs.begin(); }
414 const_iterator end() const { return Attrs.end(); }
416 /// \brief Add the raw value to the internal representation.
418 /// N.B. This should be used ONLY for decoding LLVM bitcode!
419 AttrBuilder &addRawValue(uint64_t Val);
421 /// \brief Remove attributes that are used on functions only.
422 void removeFunctionOnlyAttrs() {
423 removeAttribute(Attribute::NoReturn)
424 .removeAttribute(Attribute::NoUnwind)
425 .removeAttribute(Attribute::ReadNone)
426 .removeAttribute(Attribute::ReadOnly)
427 .removeAttribute(Attribute::NoInline)
428 .removeAttribute(Attribute::AlwaysInline)
429 .removeAttribute(Attribute::OptimizeForSize)
430 .removeAttribute(Attribute::StackProtect)
431 .removeAttribute(Attribute::StackProtectReq)
432 .removeAttribute(Attribute::StackProtectStrong)
433 .removeAttribute(Attribute::NoRedZone)
434 .removeAttribute(Attribute::NoImplicitFloat)
435 .removeAttribute(Attribute::Naked)
436 .removeAttribute(Attribute::InlineHint)
437 .removeAttribute(Attribute::StackAlignment)
438 .removeAttribute(Attribute::UWTable)
439 .removeAttribute(Attribute::NonLazyBind)
440 .removeAttribute(Attribute::ReturnsTwice)
441 .removeAttribute(Attribute::AddressSafety)
442 .removeAttribute(Attribute::MinSize)
443 .removeAttribute(Attribute::NoDuplicate);
446 uint64_t Raw() const;
448 bool operator==(const AttrBuilder &B);
449 bool operator!=(const AttrBuilder &B) {
450 return !(*this == B);
454 namespace AttributeFuncs {
456 /// \brief Which attributes cannot be applied to a type.
457 Attribute typeIncompatible(Type *Ty);
459 /// \brief This returns an integer containing an encoding of all the LLVM
460 /// attributes found in the given attribute bitset. Any change to this encoding
461 /// is a breaking change to bitcode compatibility.
462 uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index);
464 /// \brief This returns an attribute bitset containing the LLVM attributes that
465 /// have been decoded from the given integer. This function must stay in sync
466 /// with 'encodeLLVMAttributesForBitcode'.
467 Attribute decodeLLVMAttributesForBitcode(LLVMContext &C,
468 uint64_t EncodedAttrs);
470 } // end AttributeFuncs namespace
472 } // end llvm namespace