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"
29 class AttributeSetImpl;
30 class AttributeSetNode;
35 //===----------------------------------------------------------------------===//
37 /// \brief Functions, function parameters, and return types can have attributes
38 /// to indicate how they should be treated by optimizations and code
39 /// generation. This class represents one of those attributes. It's light-weight
40 /// and should be passed around by-value.
43 /// This enumeration lists the attributes that can be associated with
44 /// parameters, function results, or the function itself.
46 /// Note: The `uwtable' attribute is about the ABI or the user mandating an
47 /// entry in the unwind table. The `nounwind' attribute is about an exception
48 /// passing by the function.
50 /// In a theoretical system that uses tables for profiling and SjLj for
51 /// exceptions, they would be fully independent. In a normal system that uses
52 /// tables for both, the semantics are:
54 /// nil = Needs an entry because an exception might pass by.
55 /// nounwind = No need for an entry
56 /// uwtable = Needs an entry because the ABI says so and because
57 /// an exception might pass by.
58 /// uwtable + nounwind = Needs an entry because the ABI says so.
61 // IR-Level Attributes
62 None, ///< No attributes have been set
63 AddressSafety, ///< Address safety checking is on.
64 Alignment, ///< Alignment of parameter (5 bits)
65 ///< stored as log2 of alignment with +1 bias
66 ///< 0 means unaligned (different from align(1))
67 AlwaysInline, ///< inline=always
68 ByVal, ///< Pass structure by value
69 InlineHint, ///< Source said inlining was desirable
70 InReg, ///< Force argument to be passed in register
71 MinSize, ///< Function must be optimized for size first
72 Naked, ///< Naked function
73 Nest, ///< Nested function static chain
74 NoAlias, ///< Considered to not alias after call
75 NoCapture, ///< Function creates no aliases of pointer
76 NoDuplicate, ///< Call cannot be duplicated
77 NoImplicitFloat, ///< Disable implicit floating point insts
78 NoInline, ///< inline=never
79 NonLazyBind, ///< Function is called early and/or
80 ///< often, so lazy binding isn't worthwhile
81 NoRedZone, ///< Disable redzone
82 NoReturn, ///< Mark the function as not returning
83 NoUnwind, ///< Function doesn't unwind stack
84 OptimizeForSize, ///< opt_size
85 ReadNone, ///< Function does not access memory
86 ReadOnly, ///< Function only reads from memory
87 ReturnsTwice, ///< Function can return twice
88 SExt, ///< Sign extended before/after call
89 StackAlignment, ///< Alignment of stack for function (3 bits)
90 ///< stored as log2 of alignment with +1 bias 0
91 ///< means unaligned (different from
93 StackProtect, ///< Stack protection.
94 StackProtectReq, ///< Stack protection required.
95 StackProtectStrong, ///< Strong Stack protection.
96 StructRet, ///< Hidden pointer to structure to return
97 UWTable, ///< Function must be in a unwind table
98 ZExt, ///< Zero extended before/after call
100 EndAttrKinds, ///< Sentinal value useful for loops
102 AttrKindEmptyKey, ///< Empty key value for DenseMapInfo
103 AttrKindTombstoneKey ///< Tombstone key value for DenseMapInfo
106 AttributeImpl *pImpl;
107 Attribute(AttributeImpl *A) : pImpl(A) {}
109 Attribute() : pImpl(0) {}
111 //===--------------------------------------------------------------------===//
112 // Attribute Construction
113 //===--------------------------------------------------------------------===//
115 /// \brief Return a uniquified Attribute object.
116 static Attribute get(LLVMContext &Context, AttrKind Kind, Constant *Val = 0);
117 static Attribute get(LLVMContext &Context, Constant *Kind, Constant *Val = 0);
119 /// \brief Return a uniquified Attribute object that has the specific
121 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
122 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
124 //===--------------------------------------------------------------------===//
125 // Attribute Accessors
126 //===--------------------------------------------------------------------===//
128 /// \brief Return true if the attribute is present.
129 bool hasAttribute(AttrKind Val) const;
131 /// \brief Return the kind of this attribute.
132 Constant *getAttributeKind() const;
134 /// \brief Return the value (if present) of the non-target-specific attribute.
135 ArrayRef<Constant*> getAttributeValues() const;
137 /// \brief Returns the alignment field of an attribute as a byte alignment
139 unsigned getAlignment() const;
141 /// \brief Returns the stack alignment field of an attribute as a byte
143 unsigned getStackAlignment() const;
145 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
146 /// is, presumably, for writing out the mnemonics for the assembly writer.
147 std::string getAsString() const;
149 /// \brief Equality and non-equality query methods.
150 bool operator==(AttrKind K) const;
151 bool operator!=(AttrKind K) const;
153 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
154 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
156 /// \brief Less-than operator. Useful for sorting the attributes list.
157 bool operator<(Attribute A) const;
159 void Profile(FoldingSetNodeID &ID) const {
160 ID.AddPointer(pImpl);
163 // FIXME: Remove this.
164 uint64_t Raw() const;
167 //===----------------------------------------------------------------------===//
169 /// \brief This class manages the ref count for the opaque AttributeSetImpl
170 /// object and provides accessors for it.
178 friend class AttrBuilder;
179 friend class AttributeSetImpl;
181 /// \brief The attributes that we are managing. This can be null to represent
182 /// the empty attributes list.
183 AttributeSetImpl *pImpl;
185 /// \brief The attributes for the specified index are returned.
186 AttributeSetNode *getAttributes(unsigned Idx) const;
188 /// \brief Create an AttributeSet with the specified parameters in it.
189 static AttributeSet get(LLVMContext &C,
190 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
191 static AttributeSet get(LLVMContext &C,
192 ArrayRef<std::pair<unsigned,
193 AttributeSetNode*> > Attrs);
195 static AttributeSet getImpl(LLVMContext &C,
196 ArrayRef<std::pair<unsigned,
197 AttributeSetNode*> > Attrs);
200 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
202 AttributeSet() : pImpl(0) {}
203 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
204 const AttributeSet &operator=(const AttributeSet &RHS) {
209 //===--------------------------------------------------------------------===//
210 // AttributeSet Construction and Mutation
211 //===--------------------------------------------------------------------===//
213 /// \brief Return an AttributeSet with the specified parameters in it.
214 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
215 static AttributeSet get(LLVMContext &C, unsigned Idx,
216 ArrayRef<Attribute::AttrKind> Kind);
217 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
219 /// \brief Add an attribute to the attribute set at the given index. Since
220 /// attribute sets are immutable, this returns a new set.
221 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
222 Attribute::AttrKind Attr) const;
224 /// \brief Add attributes to the attribute set at the given index. Since
225 /// attribute sets are immutable, this returns a new set.
226 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
227 AttributeSet Attrs) const;
229 /// \brief Remove the specified attribute at the specified index from this
230 /// attribute list. Since attribute lists are immutable, this returns the new
232 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
233 Attribute::AttrKind Attr) const;
235 /// \brief Remove the specified attributes at the specified index from this
236 /// attribute list. Since attribute lists are immutable, this returns the new
238 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
239 AttributeSet Attrs) const;
241 //===--------------------------------------------------------------------===//
242 // AttributeSet Accessors
243 //===--------------------------------------------------------------------===//
245 /// \brief The attributes for the specified index are returned.
246 AttributeSet getParamAttributes(unsigned Idx) const;
248 /// \brief The attributes for the ret value are returned.
249 AttributeSet getRetAttributes() const;
251 /// \brief The function attributes are returned.
252 AttributeSet getFnAttributes() const;
254 /// \brief Return true if the attribute exists at the given index.
255 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
257 /// \brief Return true if attribute exists at the given index.
258 bool hasAttributes(unsigned Index) const;
260 /// \brief Return true if the specified attribute is set for at least one
261 /// parameter or for the return value.
262 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
264 /// \brief Return the alignment for the specified function parameter.
265 unsigned getParamAlignment(unsigned Idx) const;
267 /// \brief Get the stack alignment.
268 unsigned getStackAlignment(unsigned Index) const;
270 /// \brief Return the attributes at the index as a string.
271 std::string getAsString(unsigned Index) const;
273 /// operator==/!= - Provide equality predicates.
274 bool operator==(const AttributeSet &RHS) const {
275 return pImpl == RHS.pImpl;
277 bool operator!=(const AttributeSet &RHS) const {
278 return pImpl != RHS.pImpl;
281 //===--------------------------------------------------------------------===//
282 // AttributeSet Introspection
283 //===--------------------------------------------------------------------===//
285 // FIXME: Remove this.
286 uint64_t Raw(unsigned Index) const;
288 /// \brief Return a raw pointer that uniquely identifies this attribute list.
289 void *getRawPointer() const {
293 /// \brief Return true if there are no attributes.
294 bool isEmpty() const {
295 return getNumSlots() == 0;
298 /// \brief Return the number of slots used in this attribute list. This is
299 /// the number of arguments that have an attribute set on them (including the
300 /// function itself).
301 unsigned getNumSlots() const;
303 /// \brief Return the index for the given slot.
304 uint64_t getSlotIndex(unsigned Slot) const;
306 /// \brief Return the attributes at the given slot.
307 AttributeSet getSlotAttributes(unsigned Slot) const;
312 //===----------------------------------------------------------------------===//
314 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
316 template<> struct DenseMapInfo<Attribute::AttrKind> {
317 static inline Attribute::AttrKind getEmptyKey() {
318 return Attribute::AttrKindEmptyKey;
320 static inline Attribute::AttrKind getTombstoneKey() {
321 return Attribute::AttrKindTombstoneKey;
323 static unsigned getHashValue(const Attribute::AttrKind &Val) {
326 static bool isEqual(const Attribute::AttrKind &LHS,
327 const Attribute::AttrKind &RHS) {
332 //===----------------------------------------------------------------------===//
334 /// \brief This class is used in conjunction with the Attribute::get method to
335 /// create an Attribute object. The object itself is uniquified. The Builder's
336 /// value, however, is not. So this can be used as a quick way to test for
337 /// equality, presence of attributes, etc.
339 DenseSet<Attribute::AttrKind> Attrs;
341 uint64_t StackAlignment;
343 AttrBuilder() : Alignment(0), StackAlignment(0) {}
344 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
347 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
350 AttrBuilder(AttributeSet AS, unsigned Idx);
354 /// \brief Add an attribute to the builder.
355 AttrBuilder &addAttribute(Attribute::AttrKind Val);
357 /// \brief Remove an attribute from the builder.
358 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
360 /// \brief Add the attributes to the builder.
361 AttrBuilder &addAttributes(Attribute A);
363 /// \brief Remove the attributes from the builder.
364 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
366 /// \brief Return true if the builder has the specified attribute.
367 bool contains(Attribute::AttrKind A) const;
369 /// \brief Return true if the builder has IR-level attributes.
370 bool hasAttributes() const;
372 /// \brief Return true if the builder has any attribute that's in the
373 /// specified attribute.
374 bool hasAttributes(AttributeSet A, uint64_t Index) const;
376 /// \brief Return true if the builder has an alignment attribute.
377 bool hasAlignmentAttr() const;
379 /// \brief Retrieve the alignment attribute, if it exists.
380 uint64_t getAlignment() const { return Alignment; }
382 /// \brief Retrieve the stack alignment attribute, if it exists.
383 uint64_t getStackAlignment() const { return StackAlignment; }
385 /// \brief This turns an int alignment (which must be a power of 2) into the
386 /// form used internally in Attribute.
387 AttrBuilder &addAlignmentAttr(unsigned Align);
389 /// \brief This turns an int stack alignment (which must be a power of 2) into
390 /// the form used internally in Attribute.
391 AttrBuilder &addStackAlignmentAttr(unsigned Align);
393 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
394 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
396 iterator begin() { return Attrs.begin(); }
397 iterator end() { return Attrs.end(); }
399 const_iterator begin() const { return Attrs.begin(); }
400 const_iterator end() const { return Attrs.end(); }
402 /// \brief Remove attributes that are used on functions only.
403 void removeFunctionOnlyAttrs() {
404 removeAttribute(Attribute::NoReturn)
405 .removeAttribute(Attribute::NoUnwind)
406 .removeAttribute(Attribute::ReadNone)
407 .removeAttribute(Attribute::ReadOnly)
408 .removeAttribute(Attribute::NoInline)
409 .removeAttribute(Attribute::AlwaysInline)
410 .removeAttribute(Attribute::OptimizeForSize)
411 .removeAttribute(Attribute::StackProtect)
412 .removeAttribute(Attribute::StackProtectReq)
413 .removeAttribute(Attribute::StackProtectStrong)
414 .removeAttribute(Attribute::NoRedZone)
415 .removeAttribute(Attribute::NoImplicitFloat)
416 .removeAttribute(Attribute::Naked)
417 .removeAttribute(Attribute::InlineHint)
418 .removeAttribute(Attribute::StackAlignment)
419 .removeAttribute(Attribute::UWTable)
420 .removeAttribute(Attribute::NonLazyBind)
421 .removeAttribute(Attribute::ReturnsTwice)
422 .removeAttribute(Attribute::AddressSafety)
423 .removeAttribute(Attribute::MinSize)
424 .removeAttribute(Attribute::NoDuplicate);
427 bool operator==(const AttrBuilder &B);
428 bool operator!=(const AttrBuilder &B) {
429 return !(*this == B);
432 // FIXME: Remove these.
434 /// \brief Add the raw value to the internal representation.
436 /// N.B. This should be used ONLY for decoding LLVM bitcode!
437 AttrBuilder &addRawValue(uint64_t Val);
439 uint64_t Raw() const;
442 namespace AttributeFuncs {
444 /// \brief Which attributes cannot be applied to a type.
445 AttributeSet typeIncompatible(Type *Ty, uint64_t Index);
447 /// \brief This returns an integer containing an encoding of all the LLVM
448 /// attributes found in the given attribute bitset. Any change to this encoding
449 /// is a breaking change to bitcode compatibility.
450 uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index);
452 /// \brief This fills an AttrBuilder object with the LLVM attributes that have
453 /// been decoded from the given integer. This function must stay in sync with
454 /// 'encodeLLVMAttributesForBitcode'.
455 /// N.B. This should be used only by the bitcode reader!
456 void decodeLLVMAttributesForBitcode(LLVMContext &C, AttrBuilder &B,
457 uint64_t EncodedAttrs);
459 } // end AttributeFuncs namespace
461 } // end llvm namespace