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 {
136 ID.AddPointer(pImpl);
139 // FIXME: Remove these 'operator' methods.
140 bool operator==(const Attribute &A) const {
141 return pImpl == A.pImpl;
143 bool operator!=(const Attribute &A) const {
144 return pImpl != A.pImpl;
147 uint64_t Raw() const;
149 /// \brief Which attributes cannot be applied to a type.
150 static Attribute typeIncompatible(Type *Ty);
152 /// \brief This returns an integer containing an encoding of all the LLVM
153 /// attributes found in the given attribute bitset. Any change to this
154 /// encoding is a breaking change to bitcode compatibility.
155 static uint64_t encodeLLVMAttributesForBitcode(Attribute Attrs);
157 /// \brief This returns an attribute bitset containing the LLVM attributes
158 /// that have been decoded from the given integer. This function must stay in
159 /// sync with 'encodeLLVMAttributesForBitcode'.
160 static Attribute decodeLLVMAttributesForBitcode(LLVMContext &C,
161 uint64_t EncodedAttrs);
163 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
164 /// is, presumably, for writing out the mnemonics for the assembly writer.
165 std::string getAsString() const;
168 //===----------------------------------------------------------------------===//
170 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
172 template<> struct DenseMapInfo<Attribute::AttrKind> {
173 static inline Attribute::AttrKind getEmptyKey() {
174 return Attribute::AttrKindEmptyKey;
176 static inline Attribute::AttrKind getTombstoneKey() {
177 return Attribute::AttrKindTombstoneKey;
179 static unsigned getHashValue(const Attribute::AttrKind &Val) {
182 static bool isEqual(const Attribute::AttrKind &LHS,
183 const Attribute::AttrKind &RHS) {
188 //===----------------------------------------------------------------------===//
189 // AttributeSet Smart Pointer
190 //===----------------------------------------------------------------------===//
193 class AttributeSetImpl;
194 struct AttributeWithIndex;
196 //===----------------------------------------------------------------------===//
198 /// \brief This class manages the ref count for the opaque AttributeSetImpl
199 /// object and provides accessors for it.
207 friend class AttrBuilder;
209 /// \brief The attributes that we are managing. This can be null to represent
210 /// the empty attributes list.
211 AttributeSetImpl *AttrList;
213 /// \brief The attributes for the specified index are returned. Attributes
214 /// for the result are denoted with Idx = 0.
215 Attribute getAttributes(unsigned Idx) const;
217 /// \brief Add the specified attribute at the specified index to this
218 /// attribute list. Since attribute lists are immutable, this returns the new
220 AttributeSet addAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
222 /// \brief Remove the specified attribute at the specified index from this
223 /// attribute list. Since attribute lists are immutable, this returns the new
225 AttributeSet removeAttr(LLVMContext &C, unsigned Idx, Attribute Attrs) const;
227 explicit AttributeSet(AttributeSetImpl *LI) : AttrList(LI) {}
229 AttributeSet() : AttrList(0) {}
230 AttributeSet(const AttributeSet &P) : AttrList(P.AttrList) {}
231 const AttributeSet &operator=(const AttributeSet &RHS);
233 //===--------------------------------------------------------------------===//
234 // Attribute List Construction and Mutation
235 //===--------------------------------------------------------------------===//
237 /// \brief Return an AttributeSet with the specified parameters in it.
238 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeWithIndex> Attrs);
239 static AttributeSet get(LLVMContext &C, unsigned Idx,
240 Attribute::AttrKind Kind);
241 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
243 /// \brief Add an attribute to the attribute set at the given index. Since
244 /// attribute sets are immutable, this returns a new set.
245 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
246 Attribute::AttrKind Attr) const;
248 /// \brief Add attributes to the attribute set at the given index. Since
249 /// attribute sets are immutable, this returns a new set.
250 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
251 AttributeSet Attrs) const;
253 /// \brief Add return attributes to this attribute set. Since attribute sets
254 /// are immutable, this returns a new set.
255 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const {
256 return addAttributes(C, ReturnIndex, Attrs);
259 /// \brief Add function attributes to this attribute set. Since attribute sets
260 /// are immutable, this returns a new set.
261 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const {
262 return addAttributes(C, FunctionIndex, Attrs);
265 /// \brief Remove the specified attribute at the specified index from this
266 /// attribute list. Since attribute lists are immutable, this returns the new
268 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
269 Attribute::AttrKind Attr) const;
271 /// \brief Remove the specified attributes at the specified index from this
272 /// attribute list. Since attribute lists are immutable, this returns the new
274 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
275 AttributeSet Attrs) const;
277 //===--------------------------------------------------------------------===//
278 // Attribute List Accessors
279 //===--------------------------------------------------------------------===//
281 /// \brief The attributes for the specified index are returned.
282 AttributeSet getParamAttributes(unsigned Idx) const;
284 /// \brief The attributes for the ret value are returned.
285 AttributeSet getRetAttributes() const;
287 /// \brief The function attributes are returned.
288 AttributeSet getFnAttributes() const;
290 /// \brief Return the alignment for the specified function parameter.
291 unsigned getParamAlignment(unsigned Idx) const;
293 /// \brief Return true if the attribute exists at the given index.
294 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
296 /// \brief Return true if attribute exists at the given index.
297 bool hasAttributes(unsigned Index) const;
299 /// \brief Get the stack alignment.
300 unsigned getStackAlignment(unsigned Index) const;
302 /// \brief Return the attributes at the index as a string.
303 std::string getAsString(unsigned Index) const;
305 uint64_t Raw(unsigned Index) const;
307 /// \brief Return true if the specified attribute is set for at least one
308 /// parameter or for the return value.
309 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
311 /// operator==/!= - Provide equality predicates.
312 bool operator==(const AttributeSet &RHS) const {
313 return AttrList == RHS.AttrList;
315 bool operator!=(const AttributeSet &RHS) const {
316 return AttrList != RHS.AttrList;
319 //===--------------------------------------------------------------------===//
320 // Attribute List Introspection
321 //===--------------------------------------------------------------------===//
323 /// \brief Return a raw pointer that uniquely identifies this attribute list.
324 void *getRawPointer() const {
328 // Attributes are stored as a dense set of slots, where there is one slot for
329 // each argument that has an attribute. This allows walking over the dense
330 // set instead of walking the sparse list of attributes.
332 /// \brief Return true if there are no attributes.
333 bool isEmpty() const {
334 return AttrList == 0;
337 /// \brief Return the number of slots used in this attribute list. This is
338 /// the number of arguments that have an attribute set on them (including the
339 /// function itself).
340 unsigned getNumSlots() const;
342 /// \brief Return the index for the given slot.
343 unsigned getSlotIndex(unsigned Slot) const;
345 /// \brief Return the AttributeWithIndex at the specified slot. This holds a
346 /// index number plus a set of attributes.
347 const AttributeWithIndex &getSlot(unsigned Slot) const;
352 //===----------------------------------------------------------------------===//
354 /// \brief This is just a pair of values to associate a set of attributes with
356 struct AttributeWithIndex {
357 Attribute Attrs; ///< The attributes that are set, or'd together.
358 unsigned Index; ///< Index of the parameter for which the attributes apply.
360 // FIXME: These methods all need to be revised. The first one is temporary.
361 static AttributeWithIndex get(LLVMContext &C, unsigned Idx, AttributeSet AS);
362 static AttributeWithIndex get(LLVMContext &C, unsigned Idx,
363 ArrayRef<Attribute::AttrKind> Attrs) {
364 return get(Idx, Attribute::get(C, Attrs));
366 static AttributeWithIndex get(unsigned Idx, Attribute Attrs) {
367 AttributeWithIndex P;
374 //===----------------------------------------------------------------------===//
376 /// \brief This class is used in conjunction with the Attribute::get method to
377 /// create an Attribute object. The object itself is uniquified. The Builder's
378 /// value, however, is not. So this can be used as a quick way to test for
379 /// equality, presence of attributes, etc.
381 DenseSet<Attribute::AttrKind> Attrs;
383 uint64_t StackAlignment;
385 AttrBuilder() : Alignment(0), StackAlignment(0) {}
386 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) {
389 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
392 AttrBuilder(AttributeSet AS, unsigned Idx);
396 /// \brief Add an attribute to the builder.
397 AttrBuilder &addAttribute(Attribute::AttrKind Val);
399 /// \brief Remove an attribute from the builder.
400 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
402 /// \brief Add the attributes from A to the builder.
403 AttrBuilder &addAttributes(const Attribute &A);
405 /// \brief Remove the attributes from A from the builder.
406 AttrBuilder &removeAttributes(const Attribute &A);
408 /// \brief Return true if the builder has the specified attribute.
409 bool contains(Attribute::AttrKind A) const;
411 /// \brief Return true if the builder has IR-level attributes.
412 bool hasAttributes() const;
414 /// \brief Return true if the builder has any attribute that's in the
415 /// specified attribute.
416 bool hasAttributes(const Attribute &A) const;
418 /// \brief Return true if the builder has an alignment attribute.
419 bool hasAlignmentAttr() const;
421 /// \brief Retrieve the alignment attribute, if it exists.
422 uint64_t getAlignment() const { return Alignment; }
424 /// \brief Retrieve the stack alignment attribute, if it exists.
425 uint64_t getStackAlignment() const { return StackAlignment; }
427 /// \brief This turns an int alignment (which must be a power of 2) into the
428 /// form used internally in Attribute.
429 AttrBuilder &addAlignmentAttr(unsigned Align);
431 /// \brief This turns an int stack alignment (which must be a power of 2) into
432 /// the form used internally in Attribute.
433 AttrBuilder &addStackAlignmentAttr(unsigned Align);
435 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
436 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
438 iterator begin() { return Attrs.begin(); }
439 iterator end() { return Attrs.end(); }
441 const_iterator begin() const { return Attrs.begin(); }
442 const_iterator end() const { return Attrs.end(); }
444 /// \brief Add the raw value to the internal representation.
446 /// N.B. This should be used ONLY for decoding LLVM bitcode!
447 AttrBuilder &addRawValue(uint64_t Val);
449 /// \brief Remove attributes that are used on functions only.
450 void removeFunctionOnlyAttrs() {
451 removeAttribute(Attribute::NoReturn)
452 .removeAttribute(Attribute::NoUnwind)
453 .removeAttribute(Attribute::ReadNone)
454 .removeAttribute(Attribute::ReadOnly)
455 .removeAttribute(Attribute::NoInline)
456 .removeAttribute(Attribute::AlwaysInline)
457 .removeAttribute(Attribute::OptimizeForSize)
458 .removeAttribute(Attribute::StackProtect)
459 .removeAttribute(Attribute::StackProtectReq)
460 .removeAttribute(Attribute::StackProtectStrong)
461 .removeAttribute(Attribute::NoRedZone)
462 .removeAttribute(Attribute::NoImplicitFloat)
463 .removeAttribute(Attribute::Naked)
464 .removeAttribute(Attribute::InlineHint)
465 .removeAttribute(Attribute::StackAlignment)
466 .removeAttribute(Attribute::UWTable)
467 .removeAttribute(Attribute::NonLazyBind)
468 .removeAttribute(Attribute::ReturnsTwice)
469 .removeAttribute(Attribute::AddressSafety)
470 .removeAttribute(Attribute::MinSize)
471 .removeAttribute(Attribute::NoDuplicate);
474 uint64_t Raw() const;
476 bool operator==(const AttrBuilder &B);
477 bool operator!=(const AttrBuilder &B) {
478 return !(*this == B);
482 } // end llvm namespace