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;
181 //===----------------------------------------------------------------------===//
183 /// \brief This is just a pair of values to associate a set of attributes with
185 struct AttributeWithIndex {
186 Attribute Attrs; ///< The attributes that are set, or'd together.
187 unsigned Index; ///< Index of the parameter for which the attributes apply.
189 static AttributeWithIndex get(unsigned Idx, Attribute Attrs) {
190 AttributeWithIndex P;
197 //===----------------------------------------------------------------------===//
199 /// \brief This class manages the ref count for the opaque AttributeSetImpl
200 /// object and provides accessors for it.
208 friend class AttrBuilder;
209 friend class AttributeSetImpl;
211 /// \brief The attributes that we are managing. This can be null to represent
212 /// the empty attributes list.
213 AttributeSetImpl *pImpl;
215 /// \brief The attributes for the specified index are returned. Attributes
216 /// for the result are denoted with Idx = 0.
217 Attribute getAttributes(unsigned Idx) const;
219 /// \brief Create an AttributeSet from the AttributeWithIndex structures.
220 /// N.B. this is only temporary. It will be disappearing in the future.
221 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeWithIndex> Attrs);
223 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
225 AttributeSet() : pImpl(0) {}
226 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
227 const AttributeSet &operator=(const AttributeSet &RHS) {
232 //===--------------------------------------------------------------------===//
233 // Attribute List Construction and Mutation
234 //===--------------------------------------------------------------------===//
236 /// \brief Return an AttributeSet with the specified parameters in it.
237 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
238 static AttributeSet get(LLVMContext &C, unsigned Idx,
239 ArrayRef<Attribute::AttrKind> Kind);
240 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
242 /// \brief Add an attribute to the attribute set at the given index. Since
243 /// attribute sets are immutable, this returns a new set.
244 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
245 Attribute::AttrKind Attr) const;
247 /// \brief Add attributes to the attribute set at the given index. Since
248 /// attribute sets are immutable, this returns a new set.
249 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
250 AttributeSet Attrs) const;
252 /// \brief Add return attributes to this attribute set. Since attribute sets
253 /// are immutable, this returns a new set.
254 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const {
255 return addAttributes(C, ReturnIndex, Attrs);
258 /// \brief Add function attributes to this attribute set. Since attribute sets
259 /// are immutable, this returns a new set.
260 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const {
261 return addAttributes(C, FunctionIndex, Attrs);
264 /// \brief Remove the specified attribute at the specified index from this
265 /// attribute list. Since attribute lists are immutable, this returns the new
267 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
268 Attribute::AttrKind Attr) const;
270 /// \brief Remove the specified attributes at the specified index from this
271 /// attribute list. Since attribute lists are immutable, this returns the new
273 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
274 AttributeSet Attrs) const;
276 //===--------------------------------------------------------------------===//
277 // Attribute Set Accessors
278 //===--------------------------------------------------------------------===//
280 /// \brief The attributes for the specified index are returned.
281 AttributeSet getParamAttributes(unsigned Idx) const;
283 /// \brief The attributes for the ret value are returned.
284 AttributeSet getRetAttributes() const;
286 /// \brief The function attributes are returned.
287 AttributeSet getFnAttributes() const;
289 /// \brief Return true if the attribute exists at the given index.
290 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
292 /// \brief Return true if attribute exists at the given index.
293 bool hasAttributes(unsigned Index) const;
295 /// \brief Return the alignment for the specified function parameter.
296 unsigned getParamAlignment(unsigned Idx) const;
298 /// \brief Get the stack alignment.
299 unsigned getStackAlignment(unsigned Index) const;
301 /// \brief Return the attributes at the index as a string.
302 std::string getAsString(unsigned Index) const;
304 uint64_t Raw(unsigned Index) const;
306 /// \brief Return true if the specified attribute is set for at least one
307 /// parameter or for the return value.
308 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
310 /// operator==/!= - Provide equality predicates.
311 bool operator==(const AttributeSet &RHS) const {
312 return pImpl == RHS.pImpl;
314 bool operator!=(const AttributeSet &RHS) const {
315 return pImpl != RHS.pImpl;
318 //===--------------------------------------------------------------------===//
319 // Attribute List Introspection
320 //===--------------------------------------------------------------------===//
322 /// \brief Return a raw pointer that uniquely identifies this attribute list.
323 void *getRawPointer() const {
327 // Attributes are stored as a dense set of slots, where there is one slot for
328 // each argument that has an attribute. This allows walking over the dense
329 // set instead of walking the sparse list of attributes.
331 /// \brief Return true if there are no attributes.
332 bool isEmpty() const {
336 /// \brief Return the number of slots used in this attribute list. This is
337 /// the number of arguments that have an attribute set on them (including the
338 /// function itself).
339 unsigned getNumSlots() const;
341 /// \brief Return the index for the given slot.
342 uint64_t getSlotIndex(unsigned Slot) const;
344 /// \brief Return the attributes at the given slot.
345 AttributeSet getSlotAttributes(unsigned Slot) const;
350 //===----------------------------------------------------------------------===//
352 /// \brief This class is used in conjunction with the Attribute::get method to
353 /// create an Attribute object. The object itself is uniquified. The Builder's
354 /// value, however, is not. So this can be used as a quick way to test for
355 /// equality, presence of attributes, etc.
357 DenseSet<Attribute::AttrKind> Attrs;
359 uint64_t StackAlignment;
361 AttrBuilder() : Alignment(0), StackAlignment(0) {}
362 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
365 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
368 AttrBuilder(AttributeSet AS, unsigned Idx);
372 /// \brief Add an attribute to the builder.
373 AttrBuilder &addAttribute(Attribute::AttrKind Val);
375 /// \brief Remove an attribute from the builder.
376 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
378 /// \brief Add the attributes to the builder.
379 AttrBuilder &addAttributes(Attribute A);
381 /// \brief Remove the attributes from the builder.
382 AttrBuilder &removeAttributes(Attribute A);
384 /// \brief Add the attributes to the builder.
385 AttrBuilder &addAttributes(AttributeSet A);
387 /// \brief Return true if the builder has the specified attribute.
388 bool contains(Attribute::AttrKind A) const;
390 /// \brief Return true if the builder has IR-level attributes.
391 bool hasAttributes() const;
393 /// \brief Return true if the builder has any attribute that's in the
394 /// specified attribute.
395 bool hasAttributes(const Attribute &A) const;
397 /// \brief Return true if the builder has an alignment attribute.
398 bool hasAlignmentAttr() const;
400 /// \brief Retrieve the alignment attribute, if it exists.
401 uint64_t getAlignment() const { return Alignment; }
403 /// \brief Retrieve the stack alignment attribute, if it exists.
404 uint64_t getStackAlignment() const { return StackAlignment; }
406 /// \brief This turns an int alignment (which must be a power of 2) into the
407 /// form used internally in Attribute.
408 AttrBuilder &addAlignmentAttr(unsigned Align);
410 /// \brief This turns an int stack alignment (which must be a power of 2) into
411 /// the form used internally in Attribute.
412 AttrBuilder &addStackAlignmentAttr(unsigned Align);
414 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
415 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
417 iterator begin() { return Attrs.begin(); }
418 iterator end() { return Attrs.end(); }
420 const_iterator begin() const { return Attrs.begin(); }
421 const_iterator end() const { return Attrs.end(); }
423 /// \brief Add the raw value to the internal representation.
425 /// N.B. This should be used ONLY for decoding LLVM bitcode!
426 AttrBuilder &addRawValue(uint64_t Val);
428 /// \brief Remove attributes that are used on functions only.
429 void removeFunctionOnlyAttrs() {
430 removeAttribute(Attribute::NoReturn)
431 .removeAttribute(Attribute::NoUnwind)
432 .removeAttribute(Attribute::ReadNone)
433 .removeAttribute(Attribute::ReadOnly)
434 .removeAttribute(Attribute::NoInline)
435 .removeAttribute(Attribute::AlwaysInline)
436 .removeAttribute(Attribute::OptimizeForSize)
437 .removeAttribute(Attribute::StackProtect)
438 .removeAttribute(Attribute::StackProtectReq)
439 .removeAttribute(Attribute::StackProtectStrong)
440 .removeAttribute(Attribute::NoRedZone)
441 .removeAttribute(Attribute::NoImplicitFloat)
442 .removeAttribute(Attribute::Naked)
443 .removeAttribute(Attribute::InlineHint)
444 .removeAttribute(Attribute::StackAlignment)
445 .removeAttribute(Attribute::UWTable)
446 .removeAttribute(Attribute::NonLazyBind)
447 .removeAttribute(Attribute::ReturnsTwice)
448 .removeAttribute(Attribute::AddressSafety)
449 .removeAttribute(Attribute::MinSize)
450 .removeAttribute(Attribute::NoDuplicate);
453 uint64_t Raw() const;
455 bool operator==(const AttrBuilder &B);
456 bool operator!=(const AttrBuilder &B) {
457 return !(*this == B);
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