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 //===----------------------------------------------------------------------===//
10 // This file contains the simple types necessary to represent the
11 // attributes associated with functions and their calls.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ATTRIBUTES_H
16 #define LLVM_ATTRIBUTES_H
18 #include "llvm/Support/MathExtras.h"
19 #include "llvm/ADT/ArrayRef.h"
30 /// Attributes - A bitset of attributes.
33 /// Function parameters and results can have attributes to indicate how they
34 /// should be treated by optimizations and code generation. This enumeration
35 /// lists the attributes that can be associated with parameters, function
36 /// results or the function itself.
38 /// Note that uwtable is about the ABI or the user mandating an entry in the
39 /// unwind table. The nounwind attribute is about an exception passing by the
42 /// In a theoretical system that uses tables for profiling and sjlj for
43 /// exceptions, they would be fully independent. In a normal system that uses
44 /// tables for both, the semantics are:
46 /// nil = Needs an entry because an exception might pass by.
47 /// nounwind = No need for an entry
48 /// uwtable = Needs an entry because the ABI says so and because
49 /// an exception might pass by.
50 /// uwtable + nounwind = Needs an entry because the ABI says so.
53 // IR-Level Attributes
54 None = 0, ///< No attributes have been set
55 AddressSafety = 1, ///< Address safety checking is on.
56 Alignment = 2, ///< Alignment of parameter (5 bits)
57 ///< stored as log2 of alignment with +1 bias
58 ///< 0 means unaligned different from align 1
59 AlwaysInline = 3, ///< inline=always
60 ByVal = 4, ///< Pass structure by value
61 InlineHint = 5, ///< Source said inlining was desirable
62 InReg = 6, ///< Force argument to be passed in register
63 Naked = 7, ///< Naked function
64 Nest = 8, ///< Nested function static chain
65 NoAlias = 9, ///< Considered to not alias after call
66 NoCapture = 10, ///< Function creates no aliases of pointer
67 NoImplicitFloat = 11, ///< Disable implicit floating point insts
68 NoInline = 12, ///< inline=never
69 NonLazyBind = 13, ///< Function is called early and/or
70 ///< often, so lazy binding isn't worthwhile
71 NoRedZone = 14, ///< Disable redzone
72 NoReturn = 15, ///< Mark the function as not returning
73 NoUnwind = 16, ///< Function doesn't unwind stack
74 OptimizeForSize = 17, ///< opt_size
75 ReadNone = 18, ///< Function does not access memory
76 ReadOnly = 19, ///< Function only reads from memory
77 ReturnsTwice = 20, ///< Function can return twice
78 SExt = 21, ///< Sign extended before/after call
79 StackAlignment = 22, ///< Alignment of stack for function (3 bits)
80 ///< stored as log2 of alignment with +1 bias 0
81 ///< means unaligned (different from
83 StackProtect = 23, ///< Stack protection.
84 StackProtectReq = 24, ///< Stack protection required.
85 StructRet = 25, ///< Hidden pointer to structure to return
86 UWTable = 26, ///< Function must be in a unwind table
87 ZExt = 27 ///< Zero extended before/after call
90 AttributesImpl *Attrs;
91 Attributes(AttributesImpl *A);
93 Attributes() : Attrs(0) {}
94 Attributes(const Attributes &A);
95 Attributes &operator=(const Attributes &A) {
100 /// get - Return a uniquified Attributes object. This takes the uniquified
101 /// value from the Builder and wraps it in the Attributes class.
102 static Attributes get(LLVMContext &Context, ArrayRef<AttrVal> Vals);
103 static Attributes get(LLVMContext &Context, AttrBuilder &B);
105 /// @brief Return true if the attribute is present.
106 bool hasAttribute(AttrVal Val) const;
108 /// @brief Return true if attributes exist
109 bool hasAttributes() const;
111 /// @brief Return true if the attributes are a non-null intersection.
112 bool hasAttributes(const Attributes &A) const;
114 /// @brief Returns the alignment field of an attribute as a byte alignment
116 unsigned getAlignment() const;
118 /// @brief Returns the stack alignment field of an attribute as a byte
120 unsigned getStackAlignment() const;
122 /// @brief Parameter attributes that do not apply to vararg call arguments.
123 bool hasIncompatibleWithVarArgsAttrs() const {
124 return hasAttribute(Attributes::StructRet);
127 /// @brief Attributes that only apply to function parameters.
128 bool hasParameterOnlyAttrs() const {
129 return hasAttribute(Attributes::ByVal) ||
130 hasAttribute(Attributes::Nest) ||
131 hasAttribute(Attributes::StructRet) ||
132 hasAttribute(Attributes::NoCapture);
135 /// @brief Attributes that may be applied to the function itself. These cannot
136 /// be used on return values or function parameters.
137 bool hasFunctionOnlyAttrs() const {
138 return hasAttribute(Attributes::NoReturn) ||
139 hasAttribute(Attributes::NoUnwind) ||
140 hasAttribute(Attributes::ReadNone) ||
141 hasAttribute(Attributes::ReadOnly) ||
142 hasAttribute(Attributes::NoInline) ||
143 hasAttribute(Attributes::AlwaysInline) ||
144 hasAttribute(Attributes::OptimizeForSize) ||
145 hasAttribute(Attributes::StackProtect) ||
146 hasAttribute(Attributes::StackProtectReq) ||
147 hasAttribute(Attributes::NoRedZone) ||
148 hasAttribute(Attributes::NoImplicitFloat) ||
149 hasAttribute(Attributes::Naked) ||
150 hasAttribute(Attributes::InlineHint) ||
151 hasAttribute(Attributes::StackAlignment) ||
152 hasAttribute(Attributes::UWTable) ||
153 hasAttribute(Attributes::NonLazyBind) ||
154 hasAttribute(Attributes::ReturnsTwice) ||
155 hasAttribute(Attributes::AddressSafety);
158 bool operator==(const Attributes &A) const {
159 return Attrs == A.Attrs;
161 bool operator!=(const Attributes &A) const {
162 return Attrs != A.Attrs;
165 uint64_t Raw() const;
167 /// @brief Which attributes cannot be applied to a type.
168 static Attributes typeIncompatible(Type *Ty);
170 /// encodeLLVMAttributesForBitcode - This returns an integer containing an
171 /// encoding of all the LLVM attributes found in the given attribute bitset.
172 /// Any change to this encoding is a breaking change to bitcode compatibility.
173 static uint64_t encodeLLVMAttributesForBitcode(Attributes Attrs);
175 /// decodeLLVMAttributesForBitcode - This returns an attribute bitset
176 /// containing the LLVM attributes that have been decoded from the given
177 /// integer. This function must stay in sync with
178 /// 'encodeLLVMAttributesForBitcode'.
179 static Attributes decodeLLVMAttributesForBitcode(LLVMContext &C,
180 uint64_t EncodedAttrs);
182 /// getAsString - The set of Attributes set in Attributes is converted to a
183 /// string of equivalent mnemonics. This is, presumably, for writing out the
184 /// mnemonics for the assembly writer.
185 /// @brief Convert attribute bits to text
186 std::string getAsString() const;
189 //===----------------------------------------------------------------------===//
190 /// AttrBuilder - This class is used in conjunction with the Attributes::get
191 /// method to create an Attributes object. The object itself is uniquified. The
192 /// Builder's value, however, is not. So this can be used as a quick way to test
193 /// for equality, presence of attributes, etc.
195 friend class Attributes;
198 AttrBuilder() : Bits(0) {}
199 explicit AttrBuilder(uint64_t B) : Bits(B) {}
200 AttrBuilder(const Attributes &A) : Bits(A.Raw()) {}
201 AttrBuilder(const AttrBuilder &B) : Bits(B.Bits) {}
203 void clear() { Bits = 0; }
205 /// addAttribute - Add an attribute to the builder.
206 AttrBuilder &addAttribute(Attributes::AttrVal Val);
208 /// removeAttribute - Remove an attribute from the builder.
209 AttrBuilder &removeAttribute(Attributes::AttrVal Val);
211 /// addAttribute - Add the attributes from A to the builder.
212 AttrBuilder &addAttributes(const Attributes &A);
214 /// removeAttribute - Remove the attributes from A from the builder.
215 AttrBuilder &removeAttributes(const Attributes &A);
217 /// hasAttribute - Return true if the builder has the specified attribute.
218 bool hasAttribute(Attributes::AttrVal A) const;
220 /// hasAttributes - Return true if the builder has IR-level attributes.
221 bool hasAttributes() const;
223 /// hasAttributes - Return true if the builder has any attribute that's in the
224 /// specified attribute.
225 bool hasAttributes(const Attributes &A) const;
227 /// hasAlignmentAttr - Return true if the builder has an alignment attribute.
228 bool hasAlignmentAttr() const;
230 /// getAlignment - Retrieve the alignment attribute, if it exists.
231 uint64_t getAlignment() const;
233 /// getStackAlignment - Retrieve the stack alignment attribute, if it exists.
234 uint64_t getStackAlignment() const;
236 /// addAlignmentAttr - This turns an int alignment (which must be a power of
237 /// 2) into the form used internally in Attributes.
238 AttrBuilder &addAlignmentAttr(unsigned Align);
240 /// addStackAlignmentAttr - This turns an int stack alignment (which must be a
241 /// power of 2) into the form used internally in Attributes.
242 AttrBuilder &addStackAlignmentAttr(unsigned Align);
244 /// addRawValue - Add the raw value to the internal representation.
245 /// N.B. This should be used ONLY for decoding LLVM bitcode!
246 AttrBuilder &addRawValue(uint64_t Val);
248 /// @brief Remove attributes that are used on functions only.
249 void removeFunctionOnlyAttrs() {
250 removeAttribute(Attributes::NoReturn)
251 .removeAttribute(Attributes::NoUnwind)
252 .removeAttribute(Attributes::ReadNone)
253 .removeAttribute(Attributes::ReadOnly)
254 .removeAttribute(Attributes::NoInline)
255 .removeAttribute(Attributes::AlwaysInline)
256 .removeAttribute(Attributes::OptimizeForSize)
257 .removeAttribute(Attributes::StackProtect)
258 .removeAttribute(Attributes::StackProtectReq)
259 .removeAttribute(Attributes::NoRedZone)
260 .removeAttribute(Attributes::NoImplicitFloat)
261 .removeAttribute(Attributes::Naked)
262 .removeAttribute(Attributes::InlineHint)
263 .removeAttribute(Attributes::StackAlignment)
264 .removeAttribute(Attributes::UWTable)
265 .removeAttribute(Attributes::NonLazyBind)
266 .removeAttribute(Attributes::ReturnsTwice)
267 .removeAttribute(Attributes::AddressSafety);
270 bool operator==(const AttrBuilder &B) {
271 return Bits == B.Bits;
273 bool operator!=(const AttrBuilder &B) {
274 return Bits != B.Bits;
278 //===----------------------------------------------------------------------===//
279 // AttributeWithIndex
280 //===----------------------------------------------------------------------===//
282 /// AttributeWithIndex - This is just a pair of values to associate a set of
283 /// attributes with an index.
284 struct AttributeWithIndex {
285 Attributes Attrs; ///< The attributes that are set, or'd together.
286 unsigned Index; ///< Index of the parameter for which the attributes apply.
287 ///< Index 0 is used for return value attributes.
288 ///< Index ~0U is used for function attributes.
290 static AttributeWithIndex get(LLVMContext &C, unsigned Idx,
291 ArrayRef<Attributes::AttrVal> Attrs) {
294 for (ArrayRef<Attributes::AttrVal>::iterator I = Attrs.begin(),
295 E = Attrs.end(); I != E; ++I)
298 AttributeWithIndex P;
300 P.Attrs = Attributes::get(C, B);
303 static AttributeWithIndex get(unsigned Idx, Attributes Attrs) {
304 AttributeWithIndex P;
311 //===----------------------------------------------------------------------===//
312 // AttrListPtr Smart Pointer
313 //===----------------------------------------------------------------------===//
315 class AttributeListImpl;
317 /// AttrListPtr - This class manages the ref count for the opaque
318 /// AttributeListImpl object and provides accessors for it.
326 /// AttrList - The attributes that we are managing. This can be null
327 /// to represent the empty attributes list.
328 AttributeListImpl *AttrList;
330 AttrListPtr() : AttrList(0) {}
331 AttrListPtr(const AttrListPtr &P);
332 const AttrListPtr &operator=(const AttrListPtr &RHS);
335 //===--------------------------------------------------------------------===//
336 // Attribute List Construction and Mutation
337 //===--------------------------------------------------------------------===//
339 /// get - Return a Attributes list with the specified parameters in it.
340 static AttrListPtr get(ArrayRef<AttributeWithIndex> Attrs);
342 /// addAttr - Add the specified attribute at the specified index to this
343 /// attribute list. Since attribute lists are immutable, this
344 /// returns the new list.
345 AttrListPtr addAttr(LLVMContext &C, unsigned Idx, Attributes Attrs) const;
347 /// removeAttr - Remove the specified attribute at the specified index from
348 /// this attribute list. Since attribute lists are immutable, this
349 /// returns the new list.
350 AttrListPtr removeAttr(LLVMContext &C, unsigned Idx, Attributes Attrs) const;
352 //===--------------------------------------------------------------------===//
353 // Attribute List Accessors
354 //===--------------------------------------------------------------------===//
355 /// getParamAttributes - The attributes for the specified index are
357 Attributes getParamAttributes(unsigned Idx) const {
358 return getAttributes(Idx);
361 /// getRetAttributes - The attributes for the ret value are
363 Attributes getRetAttributes() const {
364 return getAttributes(ReturnIndex);
367 /// getFnAttributes - The function attributes are returned.
368 Attributes getFnAttributes() const {
369 return getAttributes(FunctionIndex);
372 /// paramHasAttr - Return true if the specified parameter index has the
373 /// specified attribute set.
374 bool paramHasAttr(unsigned Idx, Attributes Attr) const {
375 return getAttributes(Idx).hasAttributes(Attr);
378 /// getParamAlignment - Return the alignment for the specified function
380 unsigned getParamAlignment(unsigned Idx) const {
381 return getAttributes(Idx).getAlignment();
384 /// hasAttrSomewhere - Return true if the specified attribute is set for at
385 /// least one parameter or for the return value.
386 bool hasAttrSomewhere(Attributes::AttrVal Attr) const;
388 unsigned getNumAttrs() const;
389 Attributes &getAttributesAtIndex(unsigned i) const;
391 /// operator==/!= - Provide equality predicates.
392 bool operator==(const AttrListPtr &RHS) const
393 { return AttrList == RHS.AttrList; }
394 bool operator!=(const AttrListPtr &RHS) const
395 { return AttrList != RHS.AttrList; }
399 //===--------------------------------------------------------------------===//
400 // Attribute List Introspection
401 //===--------------------------------------------------------------------===//
403 /// getRawPointer - Return a raw pointer that uniquely identifies this
405 void *getRawPointer() const {
409 // Attributes are stored as a dense set of slots, where there is one
410 // slot for each argument that has an attribute. This allows walking over the
411 // dense set instead of walking the sparse list of attributes.
413 /// isEmpty - Return true if there are no attributes.
415 bool isEmpty() const {
416 return AttrList == 0;
419 /// getNumSlots - Return the number of slots used in this attribute list.
420 /// This is the number of arguments that have an attribute set on them
421 /// (including the function itself).
422 unsigned getNumSlots() const;
424 /// getSlot - Return the AttributeWithIndex at the specified slot. This
425 /// holds a index number plus a set of attributes.
426 const AttributeWithIndex &getSlot(unsigned Slot) const;
429 explicit AttrListPtr(AttributeListImpl *L);
431 /// getAttributes - The attributes for the specified index are
432 /// returned. Attributes for the result are denoted with Idx = 0.
433 Attributes getAttributes(unsigned Idx) const;
436 } // End llvm namespace