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 //===--------------------------------------------------------------------===//
111 // Attribute Construction
112 //===--------------------------------------------------------------------===//
114 /// \brief Return a uniquified Attribute object.
115 static Attribute get(LLVMContext &Context, AttrKind Kind);
116 static Attribute get(LLVMContext &Context, AttrBuilder &B);
118 /// \brief Return a uniquified Attribute object that has the specific
120 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
121 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
123 //===--------------------------------------------------------------------===//
124 // Attribute Accessors
125 //===--------------------------------------------------------------------===//
127 /// \brief Return true if the attribute is present.
128 bool hasAttribute(AttrKind Val) const;
130 /// \brief Return true if attributes exist
131 bool hasAttributes() const;
133 /// \brief Returns the alignment field of an attribute as a byte alignment
135 unsigned getAlignment() const;
137 /// \brief Returns the stack alignment field of an attribute as a byte
139 unsigned getStackAlignment() const;
141 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
142 /// is, presumably, for writing out the mnemonics for the assembly writer.
143 std::string getAsString() const;
145 /// \brief Equality and non-equality query methods.
146 bool operator==(AttrKind K) const;
147 bool operator!=(AttrKind K) const;
149 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
150 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
152 /// \brief Less-than operator. Useful for sorting the attributes list.
153 bool operator<(Attribute A) const;
155 void Profile(FoldingSetNodeID &ID) const {
156 ID.AddPointer(pImpl);
159 // FIXME: Remove this.
160 uint64_t Raw() const;
163 //===----------------------------------------------------------------------===//
164 // AttributeSet Smart Pointer
165 //===----------------------------------------------------------------------===//
168 class AttributeSetImpl;
169 class AttributeSetNode;
171 //===----------------------------------------------------------------------===//
173 /// \brief This class manages the ref count for the opaque AttributeSetImpl
174 /// object and provides accessors for it.
182 friend class AttrBuilder;
183 friend class AttributeSetImpl;
185 /// \brief The attributes that we are managing. This can be null to represent
186 /// the empty attributes list.
187 AttributeSetImpl *pImpl;
189 /// \brief The attributes for the specified index are returned. Attributes
190 /// for the result are denoted with Idx = 0.
191 Attribute getAttributes(unsigned Idx) const;
193 /// \brief Create an AttributeSet with the specified parameters in it.
194 static AttributeSet get(LLVMContext &C,
195 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
196 static AttributeSet get(LLVMContext &C,
197 ArrayRef<std::pair<unsigned,
198 AttributeSetNode*> > Attrs);
200 static AttributeSet getImpl(LLVMContext &C,
201 ArrayRef<std::pair<unsigned,
202 AttributeSetNode*> > Attrs);
205 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
207 AttributeSet() : pImpl(0) {}
208 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
209 const AttributeSet &operator=(const AttributeSet &RHS) {
214 //===--------------------------------------------------------------------===//
215 // AttributeSet Construction and Mutation
216 //===--------------------------------------------------------------------===//
218 /// \brief Return an AttributeSet with the specified parameters in it.
219 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
220 static AttributeSet get(LLVMContext &C, unsigned Idx,
221 ArrayRef<Attribute::AttrKind> Kind);
222 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
224 /// \brief Add an attribute to the attribute set at the given index. Since
225 /// attribute sets are immutable, this returns a new set.
226 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
227 Attribute::AttrKind Attr) const;
229 /// \brief Add attributes to the attribute set at the given index. Since
230 /// attribute sets are immutable, this returns a new set.
231 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
232 AttributeSet Attrs) const;
234 /// \brief Add return attributes to this attribute set. Since attribute sets
235 /// are immutable, this returns a new set.
236 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const {
237 return addAttributes(C, ReturnIndex, Attrs);
240 /// \brief Add function attributes to this attribute set. Since attribute sets
241 /// are immutable, this returns a new set.
242 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const {
243 return addAttributes(C, FunctionIndex, Attrs);
246 /// \brief Remove the specified attribute at the specified index from this
247 /// attribute list. Since attribute lists are immutable, this returns the new
249 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
250 Attribute::AttrKind Attr) const;
252 /// \brief Remove the specified attributes at the specified index from this
253 /// attribute list. Since attribute lists are immutable, this returns the new
255 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
256 AttributeSet Attrs) const;
258 //===--------------------------------------------------------------------===//
259 // AttributeSet Accessors
260 //===--------------------------------------------------------------------===//
262 /// \brief The attributes for the specified index are returned.
263 AttributeSet getParamAttributes(unsigned Idx) const;
265 /// \brief The attributes for the ret value are returned.
266 AttributeSet getRetAttributes() const;
268 /// \brief The function attributes are returned.
269 AttributeSet getFnAttributes() const;
271 /// \brief Return true if the attribute exists at the given index.
272 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
274 /// \brief Return true if attribute exists at the given index.
275 bool hasAttributes(unsigned Index) const;
277 /// \brief Return true if the specified attribute is set for at least one
278 /// parameter or for the return value.
279 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
281 /// \brief Return the alignment for the specified function parameter.
282 unsigned getParamAlignment(unsigned Idx) const;
284 /// \brief Get the stack alignment.
285 unsigned getStackAlignment(unsigned Index) const;
287 /// \brief Return the attributes at the index as a string.
288 std::string getAsString(unsigned Index) const;
290 /// operator==/!= - Provide equality predicates.
291 bool operator==(const AttributeSet &RHS) const {
292 return pImpl == RHS.pImpl;
294 bool operator!=(const AttributeSet &RHS) const {
295 return pImpl != RHS.pImpl;
298 //===--------------------------------------------------------------------===//
299 // AttributeSet Introspection
300 //===--------------------------------------------------------------------===//
302 // FIXME: Remove this.
303 uint64_t Raw(unsigned Index) const;
305 /// \brief Return a raw pointer that uniquely identifies this attribute list.
306 void *getRawPointer() const {
310 /// \brief Return true if there are no attributes.
311 bool isEmpty() const {
315 /// \brief Return the number of slots used in this attribute list. This is
316 /// the number of arguments that have an attribute set on them (including the
317 /// function itself).
318 unsigned getNumSlots() const;
320 /// \brief Return the index for the given slot.
321 uint64_t getSlotIndex(unsigned Slot) const;
323 /// \brief Return the attributes at the given slot.
324 AttributeSet getSlotAttributes(unsigned Slot) const;
329 //===----------------------------------------------------------------------===//
331 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
333 template<> struct DenseMapInfo<Attribute::AttrKind> {
334 static inline Attribute::AttrKind getEmptyKey() {
335 return Attribute::AttrKindEmptyKey;
337 static inline Attribute::AttrKind getTombstoneKey() {
338 return Attribute::AttrKindTombstoneKey;
340 static unsigned getHashValue(const Attribute::AttrKind &Val) {
343 static bool isEqual(const Attribute::AttrKind &LHS,
344 const Attribute::AttrKind &RHS) {
349 //===----------------------------------------------------------------------===//
351 /// \brief This class is used in conjunction with the Attribute::get method to
352 /// create an Attribute object. The object itself is uniquified. The Builder's
353 /// value, however, is not. So this can be used as a quick way to test for
354 /// equality, presence of attributes, etc.
356 DenseSet<Attribute::AttrKind> Attrs;
358 uint64_t StackAlignment;
360 AttrBuilder() : Alignment(0), StackAlignment(0) {}
361 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
364 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
367 AttrBuilder(AttributeSet AS, unsigned Idx);
371 /// \brief Add an attribute to the builder.
372 AttrBuilder &addAttribute(Attribute::AttrKind Val);
374 /// \brief Remove an attribute from the builder.
375 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
377 /// \brief Add the attributes to the builder.
378 AttrBuilder &addAttributes(Attribute A);
380 /// \brief Remove the attributes from the builder.
381 AttrBuilder &removeAttributes(Attribute A);
383 /// \brief Add the attributes to the builder.
384 AttrBuilder &addAttributes(AttributeSet A);
386 /// \brief Return true if the builder has the specified attribute.
387 bool contains(Attribute::AttrKind A) const;
389 /// \brief Return true if the builder has IR-level attributes.
390 bool hasAttributes() const;
392 /// \brief Return true if the builder has any attribute that's in the
393 /// specified attribute.
394 bool hasAttributes(const Attribute &A) const;
396 /// \brief Return true if the builder has an alignment attribute.
397 bool hasAlignmentAttr() const;
399 /// \brief Retrieve the alignment attribute, if it exists.
400 uint64_t getAlignment() const { return Alignment; }
402 /// \brief Retrieve the stack alignment attribute, if it exists.
403 uint64_t getStackAlignment() const { return StackAlignment; }
405 /// \brief This turns an int alignment (which must be a power of 2) into the
406 /// form used internally in Attribute.
407 AttrBuilder &addAlignmentAttr(unsigned Align);
409 /// \brief This turns an int stack alignment (which must be a power of 2) into
410 /// the form used internally in Attribute.
411 AttrBuilder &addStackAlignmentAttr(unsigned Align);
413 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
414 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
416 iterator begin() { return Attrs.begin(); }
417 iterator end() { return Attrs.end(); }
418 const_iterator begin() const { return Attrs.begin(); }
419 const_iterator end() const { return Attrs.end(); }
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 bool operator==(const AttrBuilder &B);
447 bool operator!=(const AttrBuilder &B) {
448 return !(*this == B);
451 // FIXME: Remove these.
453 /// \brief Add the raw value to the internal representation.
455 /// N.B. This should be used ONLY for decoding LLVM bitcode!
456 AttrBuilder &addRawValue(uint64_t Val);
458 uint64_t Raw() const;
461 namespace AttributeFuncs {
463 /// \brief Which attributes cannot be applied to a type.
464 Attribute typeIncompatible(Type *Ty);
466 /// \brief This returns an integer containing an encoding of all the LLVM
467 /// attributes found in the given attribute bitset. Any change to this encoding
468 /// is a breaking change to bitcode compatibility.
469 uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index);
471 /// \brief This returns an attribute bitset containing the LLVM attributes that
472 /// have been decoded from the given integer. This function must stay in sync
473 /// with 'encodeLLVMAttributesForBitcode'.
474 Attribute decodeLLVMAttributesForBitcode(LLVMContext &C,
475 uint64_t EncodedAttrs);
477 } // end AttributeFuncs namespace
479 } // end llvm namespace