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"
27 /// We use this proxy POD type to allow constructing Attributes constants
28 /// using initializer lists. Do not use this class directly.
31 AttrConst operator | (const AttrConst Attrs) const {
32 AttrConst Res = {v | Attrs.v};
35 AttrConst operator ~ () const {
40 } // namespace Attribute
43 /// Attributes - A bitset of attributes.
46 Attributes() : Bits(0) { }
47 explicit Attributes(uint64_t Val) : Bits(Val) { }
48 /*implicit*/ Attributes(Attribute::AttrConst Val) : Bits(Val.v) { }
49 Attributes(const Attributes &Attrs) : Bits(Attrs.Bits) { }
50 // This is a "safe bool() operator".
51 operator const void *() const { return Bits ? this : 0; }
52 bool isEmptyOrSingleton() const { return (Bits & (Bits - 1)) == 0; }
53 Attributes &operator = (const Attributes &Attrs) {
57 bool operator == (const Attributes &Attrs) const {
58 return Bits == Attrs.Bits;
60 bool operator != (const Attributes &Attrs) const {
61 return Bits != Attrs.Bits;
63 Attributes operator | (const Attributes &Attrs) const {
64 return Attributes(Bits | Attrs.Bits);
66 Attributes operator & (const Attributes &Attrs) const {
67 return Attributes(Bits & Attrs.Bits);
69 Attributes operator ^ (const Attributes &Attrs) const {
70 return Attributes(Bits ^ Attrs.Bits);
72 Attributes &operator |= (const Attributes &Attrs) {
76 Attributes &operator &= (const Attributes &Attrs) {
80 Attributes operator ~ () const { return Attributes(~Bits); }
81 uint64_t Raw() const { return Bits; }
83 // Currently, we need less than 64 bits.
89 /// Function parameters and results can have attributes to indicate how they
90 /// should be treated by optimizations and code generation. This enumeration
91 /// lists the attributes that can be associated with parameters, function
92 /// results or the function itself.
93 /// @brief Function attributes.
95 // We declare AttrConst objects that will be used throughout the code
96 // and also raw uint64_t objects with _i suffix to be used below for other
97 // constant declarations. This is done to avoid static CTORs and at the same
98 // time to keep type-safety of Attributes.
99 #define DECLARE_LLVM_ATTRIBUTE(name, value) \
100 const uint64_t name##_i = value; \
101 const AttrConst name = {value};
103 DECLARE_LLVM_ATTRIBUTE(None,0) ///< No attributes have been set
104 DECLARE_LLVM_ATTRIBUTE(ZExt,1<<0) ///< Zero extended before/after call
105 DECLARE_LLVM_ATTRIBUTE(SExt,1<<1) ///< Sign extended before/after call
106 DECLARE_LLVM_ATTRIBUTE(NoReturn,1<<2) ///< Mark the function as not returning
107 DECLARE_LLVM_ATTRIBUTE(InReg,1<<3) ///< Force argument to be passed in register
108 DECLARE_LLVM_ATTRIBUTE(StructRet,1<<4) ///< Hidden pointer to structure to return
109 DECLARE_LLVM_ATTRIBUTE(NoUnwind,1<<5) ///< Function doesn't unwind stack
110 DECLARE_LLVM_ATTRIBUTE(NoAlias,1<<6) ///< Considered to not alias after call
111 DECLARE_LLVM_ATTRIBUTE(ByVal,1<<7) ///< Pass structure by value
112 DECLARE_LLVM_ATTRIBUTE(Nest,1<<8) ///< Nested function static chain
113 DECLARE_LLVM_ATTRIBUTE(ReadNone,1<<9) ///< Function does not access memory
114 DECLARE_LLVM_ATTRIBUTE(ReadOnly,1<<10) ///< Function only reads from memory
115 DECLARE_LLVM_ATTRIBUTE(NoInline,1<<11) ///< inline=never
116 DECLARE_LLVM_ATTRIBUTE(AlwaysInline,1<<12) ///< inline=always
117 DECLARE_LLVM_ATTRIBUTE(OptimizeForSize,1<<13) ///< opt_size
118 DECLARE_LLVM_ATTRIBUTE(StackProtect,1<<14) ///< Stack protection.
119 DECLARE_LLVM_ATTRIBUTE(StackProtectReq,1<<15) ///< Stack protection required.
120 DECLARE_LLVM_ATTRIBUTE(Alignment,31<<16) ///< Alignment of parameter (5 bits)
121 // stored as log2 of alignment with +1 bias
122 // 0 means unaligned different from align 1
123 DECLARE_LLVM_ATTRIBUTE(NoCapture,1<<21) ///< Function creates no aliases of pointer
124 DECLARE_LLVM_ATTRIBUTE(NoRedZone,1<<22) /// disable redzone
125 DECLARE_LLVM_ATTRIBUTE(NoImplicitFloat,1<<23) /// disable implicit floating point
127 DECLARE_LLVM_ATTRIBUTE(Naked,1<<24) ///< Naked function
128 DECLARE_LLVM_ATTRIBUTE(InlineHint,1<<25) ///< source said inlining was
130 DECLARE_LLVM_ATTRIBUTE(StackAlignment,7<<26) ///< Alignment of stack for
131 ///function (3 bits) stored as log2
132 ///of alignment with +1 bias
133 ///0 means unaligned (different from
135 DECLARE_LLVM_ATTRIBUTE(ReturnsTwice,1<<29) ///< Function can return twice
136 DECLARE_LLVM_ATTRIBUTE(UWTable,1<<30) ///< Function must be in a unwind
138 DECLARE_LLVM_ATTRIBUTE(NonLazyBind,1U<<31) ///< Function is called early and/or
139 /// often, so lazy binding isn't
141 DECLARE_LLVM_ATTRIBUTE(AddressSafety,1ULL<<32) ///< Address safety checking is on.
143 #undef DECLARE_LLVM_ATTRIBUTE
145 /// Note that uwtable is about the ABI or the user mandating an entry in the
146 /// unwind table. The nounwind attribute is about an exception passing by the
148 /// In a theoretical system that uses tables for profiling and sjlj for
149 /// exceptions, they would be fully independent. In a normal system that
150 /// uses tables for both, the semantics are:
151 /// nil = Needs an entry because an exception might pass by.
152 /// nounwind = No need for an entry
153 /// uwtable = Needs an entry because the ABI says so and because
154 /// an exception might pass by.
155 /// uwtable + nounwind = Needs an entry because the ABI says so.
157 /// @brief Attributes that only apply to function parameters.
158 const AttrConst ParameterOnly = {ByVal_i | Nest_i |
159 StructRet_i | NoCapture_i};
161 /// @brief Attributes that may be applied to the function itself. These cannot
162 /// be used on return values or function parameters.
163 const AttrConst FunctionOnly = {NoReturn_i | NoUnwind_i | ReadNone_i |
164 ReadOnly_i | NoInline_i | AlwaysInline_i | OptimizeForSize_i |
165 StackProtect_i | StackProtectReq_i | NoRedZone_i | NoImplicitFloat_i |
166 Naked_i | InlineHint_i | StackAlignment_i |
167 UWTable_i | NonLazyBind_i | ReturnsTwice_i | AddressSafety_i};
169 /// @brief Parameter attributes that do not apply to vararg call arguments.
170 const AttrConst VarArgsIncompatible = {StructRet_i};
172 /// @brief Attributes that are mutually incompatible.
173 const AttrConst MutuallyIncompatible[4] = {
174 {ByVal_i | InReg_i | Nest_i | StructRet_i},
176 {ReadNone_i | ReadOnly_i},
177 {NoInline_i | AlwaysInline_i}
180 /// @brief Which attributes cannot be applied to a type.
181 Attributes typeIncompatible(Type *Ty);
183 /// This turns an int alignment (a power of 2, normally) into the
184 /// form used internally in Attributes.
185 inline Attributes constructAlignmentFromInt(unsigned i) {
186 // Default alignment, allow the target to define how to align it.
190 assert(isPowerOf2_32(i) && "Alignment must be a power of two.");
191 assert(i <= 0x40000000 && "Alignment too large.");
192 return Attributes((Log2_32(i)+1) << 16);
195 /// This returns the alignment field of an attribute as a byte alignment value.
196 inline unsigned getAlignmentFromAttrs(Attributes A) {
197 Attributes Align = A & Attribute::Alignment;
201 return 1U << ((Align.Raw() >> 16) - 1);
204 /// This turns an int stack alignment (which must be a power of 2) into
205 /// the form used internally in Attributes.
206 inline Attributes constructStackAlignmentFromInt(unsigned i) {
207 // Default alignment, allow the target to define how to align it.
211 assert(isPowerOf2_32(i) && "Alignment must be a power of two.");
212 assert(i <= 0x100 && "Alignment too large.");
213 return Attributes((Log2_32(i)+1) << 26);
216 /// This returns the stack alignment field of an attribute as a byte alignment
218 inline unsigned getStackAlignmentFromAttrs(Attributes A) {
219 Attributes StackAlign = A & Attribute::StackAlignment;
223 return 1U << ((StackAlign.Raw() >> 26) - 1);
227 /// The set of Attributes set in Attributes is converted to a
228 /// string of equivalent mnemonics. This is, presumably, for writing out
229 /// the mnemonics for the assembly writer.
230 /// @brief Convert attribute bits to text
231 std::string getAsString(Attributes Attrs);
232 } // end namespace Attribute
234 /// This is just a pair of values to associate a set of attributes
236 struct AttributeWithIndex {
237 Attributes Attrs; ///< The attributes that are set, or'd together.
238 unsigned Index; ///< Index of the parameter for which the attributes apply.
239 ///< Index 0 is used for return value attributes.
240 ///< Index ~0U is used for function attributes.
242 static AttributeWithIndex get(unsigned Idx, Attributes Attrs) {
243 AttributeWithIndex P;
250 //===----------------------------------------------------------------------===//
251 // AttrListPtr Smart Pointer
252 //===----------------------------------------------------------------------===//
254 class AttributeListImpl;
256 /// AttrListPtr - This class manages the ref count for the opaque
257 /// AttributeListImpl object and provides accessors for it.
259 /// AttrList - The attributes that we are managing. This can be null
260 /// to represent the empty attributes list.
261 AttributeListImpl *AttrList;
263 AttrListPtr() : AttrList(0) {}
264 AttrListPtr(const AttrListPtr &P);
265 const AttrListPtr &operator=(const AttrListPtr &RHS);
268 //===--------------------------------------------------------------------===//
269 // Attribute List Construction and Mutation
270 //===--------------------------------------------------------------------===//
272 /// get - Return a Attributes list with the specified parameters in it.
273 static AttrListPtr get(ArrayRef<AttributeWithIndex> Attrs);
275 /// addAttr - Add the specified attribute at the specified index to this
276 /// attribute list. Since attribute lists are immutable, this
277 /// returns the new list.
278 AttrListPtr addAttr(unsigned Idx, Attributes Attrs) const;
280 /// removeAttr - Remove the specified attribute at the specified index from
281 /// this attribute list. Since attribute lists are immutable, this
282 /// returns the new list.
283 AttrListPtr removeAttr(unsigned Idx, Attributes Attrs) const;
285 //===--------------------------------------------------------------------===//
286 // Attribute List Accessors
287 //===--------------------------------------------------------------------===//
288 /// getParamAttributes - The attributes for the specified index are
290 Attributes getParamAttributes(unsigned Idx) const {
291 assert (Idx && Idx != ~0U && "Invalid parameter index!");
292 return getAttributes(Idx);
295 /// getRetAttributes - The attributes for the ret value are
297 Attributes getRetAttributes() const {
298 return getAttributes(0);
301 /// getFnAttributes - The function attributes are returned.
302 Attributes getFnAttributes() const {
303 return getAttributes(~0U);
306 /// paramHasAttr - Return true if the specified parameter index has the
307 /// specified attribute set.
308 bool paramHasAttr(unsigned Idx, Attributes Attr) const {
309 return getAttributes(Idx) & Attr;
312 /// getParamAlignment - Return the alignment for the specified function
314 unsigned getParamAlignment(unsigned Idx) const {
315 return Attribute::getAlignmentFromAttrs(getAttributes(Idx));
318 /// hasAttrSomewhere - Return true if the specified attribute is set for at
319 /// least one parameter or for the return value.
320 bool hasAttrSomewhere(Attributes Attr) const;
322 /// operator==/!= - Provide equality predicates.
323 bool operator==(const AttrListPtr &RHS) const
324 { return AttrList == RHS.AttrList; }
325 bool operator!=(const AttrListPtr &RHS) const
326 { return AttrList != RHS.AttrList; }
330 //===--------------------------------------------------------------------===//
331 // Attribute List Introspection
332 //===--------------------------------------------------------------------===//
334 /// getRawPointer - Return a raw pointer that uniquely identifies this
336 void *getRawPointer() const {
340 // Attributes are stored as a dense set of slots, where there is one
341 // slot for each argument that has an attribute. This allows walking over the
342 // dense set instead of walking the sparse list of attributes.
344 /// isEmpty - Return true if there are no attributes.
346 bool isEmpty() const {
347 return AttrList == 0;
350 /// getNumSlots - Return the number of slots used in this attribute list.
351 /// This is the number of arguments that have an attribute set on them
352 /// (including the function itself).
353 unsigned getNumSlots() const;
355 /// getSlot - Return the AttributeWithIndex at the specified slot. This
356 /// holds a index number plus a set of attributes.
357 const AttributeWithIndex &getSlot(unsigned Slot) const;
360 explicit AttrListPtr(AttributeListImpl *L);
362 /// getAttributes - The attributes for the specified index are
363 /// returned. Attributes for the result are denoted with Idx = 0.
364 Attributes getAttributes(unsigned Idx) const;
368 } // End llvm namespace