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. This takes the uniquified
111 /// value from the Builder and wraps it in the Attribute class.
112 static Attribute get(LLVMContext &Context, ArrayRef<AttrKind> Vals);
113 static Attribute get(LLVMContext &Context, AttrBuilder &B);
115 /// \brief Return true if the attribute is present.
116 bool hasAttribute(AttrKind Val) const;
118 /// \brief Return true if attributes exist
119 bool hasAttributes() const;
121 /// \brief Returns the alignment field of an attribute as a byte alignment
123 unsigned getAlignment() const;
125 /// \brief Returns the stack alignment field of an attribute as a byte
127 unsigned getStackAlignment() const;
129 /// \brief Equality and non-equality query methods.
130 bool operator==(AttrKind K) const;
131 bool operator!=(AttrKind K) const;
133 bool operator<(Attribute A) const;
135 void Profile(FoldingSetNodeID &ID) const;
137 // FIXME: Remove these 'operator' methods.
138 bool operator==(const Attribute &A) const {
139 return pImpl == A.pImpl;
141 bool operator!=(const Attribute &A) const {
142 return pImpl != A.pImpl;
145 uint64_t Raw() const;
147 /// \brief Which attributes cannot be applied to a type.
148 static Attribute typeIncompatible(Type *Ty);
150 /// \brief This returns an integer containing an encoding of all the LLVM
151 /// attributes found in the given attribute bitset. Any change to this
152 /// encoding is a breaking change to bitcode compatibility.
153 static uint64_t encodeLLVMAttributesForBitcode(Attribute Attrs);
155 /// \brief This returns an attribute bitset containing the LLVM attributes
156 /// that have been decoded from the given integer. This function must stay in
157 /// sync with 'encodeLLVMAttributesForBitcode'.
158 static Attribute decodeLLVMAttributesForBitcode(LLVMContext &C,
159 uint64_t EncodedAttrs);
161 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
162 /// is, presumably, for writing out the mnemonics for the assembly writer.
163 std::string getAsString() const;
166 //===----------------------------------------------------------------------===//
168 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
170 template<> struct DenseMapInfo<Attribute::AttrKind> {
171 static inline Attribute::AttrKind getEmptyKey() {
172 return Attribute::AttrKindEmptyKey;
174 static inline Attribute::AttrKind getTombstoneKey() {
175 return Attribute::AttrKindTombstoneKey;
177 static unsigned getHashValue(const Attribute::AttrKind &Val) {
180 static bool isEqual(const Attribute::AttrKind &LHS,
181 const Attribute::AttrKind &RHS) {
186 //===----------------------------------------------------------------------===//
187 // AttributeSet Smart Pointer
188 //===----------------------------------------------------------------------===//
191 class AttributeSetImpl;
192 struct AttributeWithIndex;
194 //===----------------------------------------------------------------------===//
196 /// \brief This class manages the ref count for the opaque AttributeSetImpl
197 /// object and provides accessors for it.
205 friend class AttrBuilder;
207 /// \brief The attributes that we are managing. This can be null to represent
208 /// the empty attributes list.
209 AttributeSetImpl *AttrList;
211 /// \brief The attributes for the specified index are returned. Attributes
212 /// for the result are denoted with Idx = 0.
213 Attribute getAttributes(unsigned Idx) const;
215 /// \brief Add the specified attribute at the specified index to this
216 /// attribute list. Since attribute lists are immutable, this returns the new
218 AttributeSet addAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
220 /// \brief Remove the specified attribute at the specified index from this
221 /// attribute list. Since attribute lists are immutable, this returns the new
223 AttributeSet removeAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
225 explicit AttributeSet(AttributeSetImpl *LI) : AttrList(LI) {}
227 AttributeSet() : AttrList(0) {}
228 AttributeSet(const AttributeSet &P) : AttrList(P.AttrList) {}
229 const AttributeSet &operator=(const AttributeSet &RHS);
231 //===--------------------------------------------------------------------===//
232 // Attribute List Construction and Mutation
233 //===--------------------------------------------------------------------===//
235 /// \brief Return an AttributeSet with the specified parameters in it.
236 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeWithIndex> Attrs);
237 static AttributeSet get(LLVMContext &C, unsigned Idx,
238 Attribute::AttrKind Kind);
239 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
241 /// \brief Add an attribute to the attribute set at the given index. Since
242 /// attribute sets are immutable, this returns a new set.
243 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
244 Attribute::AttrKind Attr) const;
246 /// \brief Add attributes to the attribute set at the given index. Since
247 /// attribute sets are immutable, this returns a new set.
248 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
249 AttributeSet Attrs) const;
251 /// \brief Add return attributes to this attribute set. Since attribute sets
252 /// are immutable, this returns a new set.
253 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const {
254 return addAttributes(C, ReturnIndex, Attrs);
257 /// \brief Add function attributes to this attribute set. Since attribute sets
258 /// are immutable, this returns a new set.
259 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const {
260 return addAttributes(C, FunctionIndex, Attrs);
263 /// \brief Remove the specified attribute at the specified index from this
264 /// attribute list. Since attribute lists are immutable, this returns the new
266 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
267 Attribute::AttrKind Attr) const;
269 /// \brief Remove the specified attributes at the specified index from this
270 /// attribute list. Since attribute lists are immutable, this returns the new
272 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
273 AttributeSet Attrs) const;
275 //===--------------------------------------------------------------------===//
276 // Attribute List Accessors
277 //===--------------------------------------------------------------------===//
279 /// \brief The attributes for the specified index are returned.
280 AttributeSet getParamAttributes(unsigned Idx) const;
282 /// \brief The attributes for the ret value are returned.
283 AttributeSet getRetAttributes() const;
285 /// \brief The function attributes are returned.
286 AttributeSet getFnAttributes() const;
288 /// \brief Return the alignment for the specified function parameter.
289 unsigned getParamAlignment(unsigned Idx) const;
291 /// \brief Return true if the attribute exists at the given index.
292 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
294 /// \brief Return true if attribute exists at the given index.
295 bool hasAttributes(unsigned Index) const;
297 /// \brief Get the stack alignment.
298 unsigned getStackAlignment(unsigned Index) const;
300 /// \brief Return the attributes at the index as a string.
301 std::string getAsString(unsigned Index) const;
303 uint64_t Raw(unsigned Index) const;
305 /// \brief Return true if the specified attribute is set for at least one
306 /// parameter or for the return value.
307 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
309 /// operator==/!= - Provide equality predicates.
310 bool operator==(const AttributeSet &RHS) const {
311 return AttrList == RHS.AttrList;
313 bool operator!=(const AttributeSet &RHS) const {
314 return AttrList != RHS.AttrList;
317 //===--------------------------------------------------------------------===//
318 // Attribute List Introspection
319 //===--------------------------------------------------------------------===//
321 /// \brief Return a raw pointer that uniquely identifies this attribute list.
322 void *getRawPointer() const {
326 // Attributes are stored as a dense set of slots, where there is one slot for
327 // each argument that has an attribute. This allows walking over the dense
328 // set instead of walking the sparse list of attributes.
330 /// \brief Return true if there are no attributes.
331 bool isEmpty() const {
332 return AttrList == 0;
335 /// \brief Return the number of slots used in this attribute list. This is
336 /// the number of arguments that have an attribute set on them (including the
337 /// function itself).
338 unsigned getNumSlots() const;
340 /// \brief Return the AttributeWithIndex at the specified slot. This holds a
341 /// index number plus a set of attributes.
342 const AttributeWithIndex &getSlot(unsigned Slot) const;
347 //===----------------------------------------------------------------------===//
349 /// \brief This is just a pair of values to associate a set of attributes with
351 struct AttributeWithIndex {
352 Attribute Attrs; ///< The attributes that are set, or'd together.
353 unsigned Index; ///< Index of the parameter for which the attributes apply.
355 // FIXME: These methods all need to be revised. The first one is temporary.
356 static AttributeWithIndex get(LLVMContext &C, unsigned Idx, AttributeSet AS);
357 static AttributeWithIndex get(LLVMContext &C, unsigned Idx,
358 ArrayRef<Attribute::AttrKind> Attrs) {
359 return get(Idx, Attribute::get(C, Attrs));
361 static AttributeWithIndex get(unsigned Idx, Attribute Attrs) {
362 AttributeWithIndex P;
369 //===----------------------------------------------------------------------===//
371 /// \brief This class is used in conjunction with the Attribute::get method to
372 /// create an Attribute object. The object itself is uniquified. The Builder's
373 /// value, however, is not. So this can be used as a quick way to test for
374 /// equality, presence of attributes, etc.
376 DenseSet<Attribute::AttrKind> Attrs;
378 uint64_t StackAlignment;
380 AttrBuilder() : Alignment(0), StackAlignment(0) {}
381 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
384 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
387 AttrBuilder(AttributeSet AS, unsigned Idx);
391 /// \brief Add an attribute to the builder.
392 AttrBuilder &addAttribute(Attribute::AttrKind Val);
394 /// \brief Remove an attribute from the builder.
395 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
397 /// \brief Add the attributes from A to the builder.
398 AttrBuilder &addAttributes(const Attribute &A);
400 /// \brief Remove the attributes from A from the builder.
401 AttrBuilder &removeAttributes(const Attribute &A);
403 /// \brief Return true if the builder has the specified attribute.
404 bool contains(Attribute::AttrKind A) const;
406 /// \brief Return true if the builder has IR-level attributes.
407 bool hasAttributes() const;
409 /// \brief Return true if the builder has any attribute that's in the
410 /// specified attribute.
411 bool hasAttributes(const Attribute &A) const;
413 /// \brief Return true if the builder has an alignment attribute.
414 bool hasAlignmentAttr() const;
416 /// \brief Retrieve the alignment attribute, if it exists.
417 uint64_t getAlignment() const { return Alignment; }
419 /// \brief Retrieve the stack alignment attribute, if it exists.
420 uint64_t getStackAlignment() const { return StackAlignment; }
422 /// \brief This turns an int alignment (which must be a power of 2) into the
423 /// form used internally in Attribute.
424 AttrBuilder &addAlignmentAttr(unsigned Align);
426 /// \brief This turns an int stack alignment (which must be a power of 2) into
427 /// the form used internally in Attribute.
428 AttrBuilder &addStackAlignmentAttr(unsigned Align);
430 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
431 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
433 iterator begin() { return Attrs.begin(); }
434 iterator end() { return Attrs.end(); }
436 const_iterator begin() const { return Attrs.begin(); }
437 const_iterator end() const { return Attrs.end(); }
439 /// \brief Add the raw value to the internal representation.
441 /// N.B. This should be used ONLY for decoding LLVM bitcode!
442 AttrBuilder &addRawValue(uint64_t Val);
444 /// \brief Remove attributes that are used on functions only.
445 void removeFunctionOnlyAttrs() {
446 removeAttribute(Attribute::NoReturn)
447 .removeAttribute(Attribute::NoUnwind)
448 .removeAttribute(Attribute::ReadNone)
449 .removeAttribute(Attribute::ReadOnly)
450 .removeAttribute(Attribute::NoInline)
451 .removeAttribute(Attribute::AlwaysInline)
452 .removeAttribute(Attribute::OptimizeForSize)
453 .removeAttribute(Attribute::StackProtect)
454 .removeAttribute(Attribute::StackProtectReq)
455 .removeAttribute(Attribute::StackProtectStrong)
456 .removeAttribute(Attribute::NoRedZone)
457 .removeAttribute(Attribute::NoImplicitFloat)
458 .removeAttribute(Attribute::Naked)
459 .removeAttribute(Attribute::InlineHint)
460 .removeAttribute(Attribute::StackAlignment)
461 .removeAttribute(Attribute::UWTable)
462 .removeAttribute(Attribute::NonLazyBind)
463 .removeAttribute(Attribute::ReturnsTwice)
464 .removeAttribute(Attribute::AddressSafety)
465 .removeAttribute(Attribute::MinSize)
466 .removeAttribute(Attribute::NoDuplicate);
469 uint64_t Raw() const;
471 bool operator==(const AttrBuilder &B);
472 bool operator!=(const AttrBuilder &B) {
473 return !(*this == B);
477 } // end llvm namespace