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/FoldingSet.h"
21 #include "llvm/Support/PointerLikeTypeTraits.h"
31 class AttributeSetImpl;
32 class AttributeSetNode;
34 template<typename T> struct DenseMapInfo;
38 //===----------------------------------------------------------------------===//
40 /// \brief Functions, function parameters, and return types can have attributes
41 /// to indicate how they should be treated by optimizations and code
42 /// generation. This class represents one of those attributes. It's light-weight
43 /// and should be passed around by-value.
46 /// This enumeration lists the attributes that can be associated with
47 /// parameters, function results, or the function itself.
49 /// Note: The `uwtable' attribute is about the ABI or the user mandating an
50 /// entry in the unwind table. The `nounwind' attribute is about an exception
51 /// passing by the function.
53 /// In a theoretical system that uses tables for profiling and SjLj for
54 /// exceptions, they would be fully independent. In a normal system that uses
55 /// tables for both, the semantics are:
57 /// nil = Needs an entry because an exception might pass by.
58 /// nounwind = No need for an entry
59 /// uwtable = Needs an entry because the ABI says so and because
60 /// an exception might pass by.
61 /// uwtable + nounwind = Needs an entry because the ABI says so.
64 // IR-Level Attributes
65 None, ///< No attributes have been set
66 AddressSafety, ///< Address safety checking is on.
67 Alignment, ///< Alignment of parameter (5 bits)
68 ///< stored as log2 of alignment with +1 bias
69 ///< 0 means unaligned (different from align(1))
70 AlwaysInline, ///< inline=always
71 ByVal, ///< Pass structure by value
72 InlineHint, ///< Source said inlining was desirable
73 InReg, ///< Force argument to be passed in register
74 MinSize, ///< Function must be optimized for size first
75 Naked, ///< Naked function
76 Nest, ///< Nested function static chain
77 NoAlias, ///< Considered to not alias after call
78 NoCapture, ///< Function creates no aliases of pointer
79 NoDuplicate, ///< Call cannot be duplicated
80 NoImplicitFloat, ///< Disable implicit floating point insts
81 NoInline, ///< inline=never
82 NonLazyBind, ///< Function is called early and/or
83 ///< often, so lazy binding isn't worthwhile
84 NoRedZone, ///< Disable redzone
85 NoReturn, ///< Mark the function as not returning
86 NoUnwind, ///< Function doesn't unwind stack
87 OptimizeForSize, ///< opt_size
88 ReadNone, ///< Function does not access memory
89 ReadOnly, ///< Function only reads from memory
90 ReturnsTwice, ///< Function can return twice
91 SExt, ///< Sign extended before/after call
92 StackAlignment, ///< Alignment of stack for function (3 bits)
93 ///< stored as log2 of alignment with +1 bias 0
94 ///< means unaligned (different from
96 StackProtect, ///< Stack protection.
97 StackProtectReq, ///< Stack protection required.
98 StackProtectStrong, ///< Strong Stack protection.
99 StructRet, ///< Hidden pointer to structure to return
100 ThreadSafety, ///< Thread safety checking is on.
101 UninitializedChecks, ///< Checking for uses of uninitialized memory is on.
102 UWTable, ///< Function must be in a unwind table
103 ZExt, ///< Zero extended before/after call
105 EndAttrKinds ///< Sentinal value useful for loops
108 AttributeImpl *pImpl;
109 Attribute(AttributeImpl *A) : pImpl(A) {}
111 Attribute() : pImpl(0) {}
113 //===--------------------------------------------------------------------===//
114 // Attribute Construction
115 //===--------------------------------------------------------------------===//
117 /// \brief Return a uniquified Attribute object.
118 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
119 static Attribute get(LLVMContext &Context, StringRef Kind,
120 StringRef Val = StringRef());
122 /// \brief Return a uniquified Attribute object that has the specific
124 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
125 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
127 //===--------------------------------------------------------------------===//
128 // Attribute Accessors
129 //===--------------------------------------------------------------------===//
131 /// \brief Return true if the attribute is an Attribute::AttrKind type.
132 bool isEnumAttribute() const;
134 /// \brief Return true if the attribute is an alignment attribute.
135 bool isAlignAttribute() const;
137 /// \brief Return true if the attribute is a string (target-dependent)
139 bool isStringAttribute() const;
141 /// \brief Return true if the attribute is present.
142 bool hasAttribute(AttrKind Val) const;
144 /// \brief Return true if the target-dependent attribute is present.
145 bool hasAttribute(StringRef Val) const;
147 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This
148 /// requires the attribute to be an enum or alignment attribute.
149 Attribute::AttrKind getKindAsEnum() const;
151 /// \brief Return the attribute's value as an integer. This requires that the
152 /// attribute be an alignment attribute.
153 uint64_t getValueAsInt() const;
155 /// \brief Return the attribute's kind as a string. This requires the
156 /// attribute to be a string attribute.
157 StringRef getKindAsString() const;
159 /// \brief Return the attribute's value as a string. This requires the
160 /// attribute to be a string attribute.
161 StringRef getValueAsString() const;
163 /// \brief Returns the alignment field of an attribute as a byte alignment
165 unsigned getAlignment() const;
167 /// \brief Returns the stack alignment field of an attribute as a byte
169 unsigned getStackAlignment() const;
171 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
172 /// is, presumably, for writing out the mnemonics for the assembly writer.
173 std::string getAsString(bool InAttrGrp = false) const;
175 /// \brief Equality and non-equality operators.
176 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
177 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
179 /// \brief Less-than operator. Useful for sorting the attributes list.
180 bool operator<(Attribute A) const;
182 void Profile(FoldingSetNodeID &ID) const {
183 ID.AddPointer(pImpl);
187 //===----------------------------------------------------------------------===//
189 /// \brief This class holds the attributes for a function, its return value, and
190 /// its parameters. You access the attributes for each of them via an index into
191 /// the AttributeSet object. The function attributes are at index
192 /// `AttributeSet::FunctionIndex', the return value is at index
193 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at
202 friend class AttrBuilder;
203 friend class AttributeSetImpl;
204 template <typename Ty> friend struct DenseMapInfo;
206 /// \brief The attributes that we are managing. This can be null to represent
207 /// the empty attributes list.
208 AttributeSetImpl *pImpl;
210 /// \brief The attributes for the specified index are returned.
211 AttributeSetNode *getAttributes(unsigned Idx) const;
213 /// \brief Create an AttributeSet with the specified parameters in it.
214 static AttributeSet get(LLVMContext &C,
215 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
216 static AttributeSet get(LLVMContext &C,
217 ArrayRef<std::pair<unsigned,
218 AttributeSetNode*> > Attrs);
220 static AttributeSet getImpl(LLVMContext &C,
221 ArrayRef<std::pair<unsigned,
222 AttributeSetNode*> > Attrs);
225 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
227 AttributeSet() : pImpl(0) {}
228 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
229 const AttributeSet &operator=(const AttributeSet &RHS) {
234 //===--------------------------------------------------------------------===//
235 // AttributeSet Construction and Mutation
236 //===--------------------------------------------------------------------===//
238 /// \brief Return an AttributeSet with the specified parameters in it.
239 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
240 static AttributeSet get(LLVMContext &C, unsigned Idx,
241 ArrayRef<Attribute::AttrKind> Kind);
242 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
244 /// \brief Add an attribute to the attribute set at the given index. Since
245 /// attribute sets are immutable, this returns a new set.
246 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
247 Attribute::AttrKind Attr) const;
249 /// \brief Add attributes to the attribute set at the given index. Since
250 /// attribute sets are immutable, this returns a new set.
251 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
252 AttributeSet Attrs) const;
254 /// \brief Remove the specified attribute at the specified index from this
255 /// attribute list. Since attribute lists are immutable, this returns the new
257 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
258 Attribute::AttrKind Attr) const;
260 /// \brief Remove the specified attributes at the specified index from this
261 /// attribute list. Since attribute lists are immutable, this returns the new
263 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
264 AttributeSet Attrs) const;
266 //===--------------------------------------------------------------------===//
267 // AttributeSet Accessors
268 //===--------------------------------------------------------------------===//
270 /// \brief Retrieve the LLVM context.
271 LLVMContext &getContext() const;
273 /// \brief The attributes for the specified index are returned.
274 AttributeSet getParamAttributes(unsigned Idx) const;
276 /// \brief The attributes for the ret value are returned.
277 AttributeSet getRetAttributes() const;
279 /// \brief The function attributes are returned.
280 AttributeSet getFnAttributes() const;
282 /// \brief Return true if the attribute exists at the given index.
283 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
285 /// \brief Return true if the attribute exists at the given index.
286 bool hasAttribute(unsigned Index, StringRef Kind) const;
288 /// \brief Return true if attribute exists at the given index.
289 bool hasAttributes(unsigned Index) const;
291 /// \brief Return true if the specified attribute is set for at least one
292 /// parameter or for the return value.
293 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
295 /// \brief Return the attribute object that exists at the given index.
296 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const;
298 /// \brief Return the attribute object that exists at the given index.
299 Attribute getAttribute(unsigned Index, StringRef Kind) const;
301 /// \brief Return the alignment for the specified function parameter.
302 unsigned getParamAlignment(unsigned Idx) const;
304 /// \brief Get the stack alignment.
305 unsigned getStackAlignment(unsigned Index) const;
307 /// \brief Return the attributes at the index as a string.
308 std::string getAsString(unsigned Index, bool InAttrGrp = false) const;
310 typedef ArrayRef<Attribute>::iterator iterator;
312 iterator begin(unsigned Idx) const;
313 iterator end(unsigned Idx) const;
315 /// operator==/!= - Provide equality predicates.
316 bool operator==(const AttributeSet &RHS) const {
317 return pImpl == RHS.pImpl;
319 bool operator!=(const AttributeSet &RHS) const {
320 return pImpl != RHS.pImpl;
323 //===--------------------------------------------------------------------===//
324 // AttributeSet Introspection
325 //===--------------------------------------------------------------------===//
327 // FIXME: Remove this.
328 uint64_t Raw(unsigned Index) const;
330 /// \brief Return a raw pointer that uniquely identifies this attribute list.
331 void *getRawPointer() const {
335 /// \brief Return true if there are no attributes.
336 bool isEmpty() const {
337 return getNumSlots() == 0;
340 /// \brief Return the number of slots used in this attribute list. This is
341 /// the number of arguments that have an attribute set on them (including the
342 /// function itself).
343 unsigned getNumSlots() const;
345 /// \brief Return the index for the given slot.
346 uint64_t getSlotIndex(unsigned Slot) const;
348 /// \brief Return the attributes at the given slot.
349 AttributeSet getSlotAttributes(unsigned Slot) const;
354 //===----------------------------------------------------------------------===//
356 /// \brief Provide DenseMapInfo for AttributeSet.
357 template<> struct DenseMapInfo<AttributeSet> {
358 static inline AttributeSet getEmptyKey() {
359 uintptr_t Val = static_cast<uintptr_t>(-1);
360 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
361 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
363 static inline AttributeSet getTombstoneKey() {
364 uintptr_t Val = static_cast<uintptr_t>(-2);
365 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
366 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
368 static unsigned getHashValue(AttributeSet AS) {
369 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
370 (unsigned((uintptr_t)AS.pImpl) >> 9);
372 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
375 //===----------------------------------------------------------------------===//
377 /// \brief This class is used in conjunction with the Attribute::get method to
378 /// create an Attribute object. The object itself is uniquified. The Builder's
379 /// value, however, is not. So this can be used as a quick way to test for
380 /// equality, presence of attributes, etc.
382 std::bitset<Attribute::EndAttrKinds> Attrs;
383 std::map<std::string, std::string> TargetDepAttrs;
385 uint64_t StackAlignment;
387 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {}
388 explicit AttrBuilder(uint64_t Val)
389 : Attrs(0), Alignment(0), StackAlignment(0) {
392 AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) {
395 AttrBuilder(AttributeSet AS, unsigned Idx);
396 AttrBuilder(const AttrBuilder &B)
398 TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()),
399 Alignment(B.Alignment), StackAlignment(B.StackAlignment) {}
403 /// \brief Add an attribute to the builder.
404 AttrBuilder &addAttribute(Attribute::AttrKind Val);
406 /// \brief Add the Attribute object to the builder.
407 AttrBuilder &addAttribute(Attribute A);
409 /// \brief Add the target-dependent attribute to the builder.
410 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef());
412 /// \brief Remove an attribute from the builder.
413 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
415 /// \brief Remove the attributes from the builder.
416 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
418 /// \brief Remove the target-dependent attribute to the builder.
419 AttrBuilder &removeAttribute(StringRef A);
421 /// \brief Add the attributes from the builder.
422 AttrBuilder &merge(const AttrBuilder &B);
424 /// \brief Return true if the builder has the specified attribute.
425 bool contains(Attribute::AttrKind A) const {
426 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!");
430 /// \brief Return true if the builder has the specified target-dependent
432 bool contains(StringRef A) const;
434 /// \brief Return true if the builder has IR-level attributes.
435 bool hasAttributes() const;
437 /// \brief Return true if the builder has any attribute that's in the
438 /// specified attribute.
439 bool hasAttributes(AttributeSet A, uint64_t Index) const;
441 /// \brief Return true if the builder has an alignment attribute.
442 bool hasAlignmentAttr() const;
444 /// \brief Retrieve the alignment attribute, if it exists.
445 uint64_t getAlignment() const { return Alignment; }
447 /// \brief Retrieve the stack alignment attribute, if it exists.
448 uint64_t getStackAlignment() const { return StackAlignment; }
450 /// \brief This turns an int alignment (which must be a power of 2) into the
451 /// form used internally in Attribute.
452 AttrBuilder &addAlignmentAttr(unsigned Align);
454 /// \brief This turns an int stack alignment (which must be a power of 2) into
455 /// the form used internally in Attribute.
456 AttrBuilder &addStackAlignmentAttr(unsigned Align);
458 /// \brief Return true if the builder contains no target-independent
460 bool empty() const { return Attrs.none(); }
462 // Iterators for target-dependent attributes.
463 typedef std::pair<std::string, std::string> td_type;
464 typedef std::map<std::string, std::string>::iterator td_iterator;
465 typedef std::map<std::string, std::string>::const_iterator td_const_iterator;
467 td_iterator td_begin() { return TargetDepAttrs.begin(); }
468 td_iterator td_end() { return TargetDepAttrs.end(); }
470 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
471 td_const_iterator td_end() const { return TargetDepAttrs.end(); }
473 bool td_empty() const { return TargetDepAttrs.empty(); }
475 /// \brief Remove attributes that are used on functions only.
476 void removeFunctionOnlyAttrs() {
477 removeAttribute(Attribute::NoReturn)
478 .removeAttribute(Attribute::NoUnwind)
479 .removeAttribute(Attribute::ReadNone)
480 .removeAttribute(Attribute::ReadOnly)
481 .removeAttribute(Attribute::NoInline)
482 .removeAttribute(Attribute::AlwaysInline)
483 .removeAttribute(Attribute::OptimizeForSize)
484 .removeAttribute(Attribute::StackProtect)
485 .removeAttribute(Attribute::StackProtectReq)
486 .removeAttribute(Attribute::StackProtectStrong)
487 .removeAttribute(Attribute::NoRedZone)
488 .removeAttribute(Attribute::NoImplicitFloat)
489 .removeAttribute(Attribute::Naked)
490 .removeAttribute(Attribute::InlineHint)
491 .removeAttribute(Attribute::StackAlignment)
492 .removeAttribute(Attribute::UWTable)
493 .removeAttribute(Attribute::NonLazyBind)
494 .removeAttribute(Attribute::ReturnsTwice)
495 .removeAttribute(Attribute::AddressSafety)
496 .removeAttribute(Attribute::ThreadSafety)
497 .removeAttribute(Attribute::UninitializedChecks)
498 .removeAttribute(Attribute::MinSize)
499 .removeAttribute(Attribute::NoDuplicate);
502 bool operator==(const AttrBuilder &B);
503 bool operator!=(const AttrBuilder &B) {
504 return !(*this == B);
507 // FIXME: Remove this in 4.0.
509 /// \brief Add the raw value to the internal representation.
510 AttrBuilder &addRawValue(uint64_t Val);
513 namespace AttributeFuncs {
515 /// \brief Which attributes cannot be applied to a type.
516 AttributeSet typeIncompatible(Type *Ty, uint64_t Index);
518 } // end AttributeFuncs namespace
520 } // end llvm namespace