1 //===-- llvm/Attributes.h - Container for ParamAttrs ---*---------- 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 parameter
11 // attributes associated with functions and their calls.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_PARAMETER_ATTRIBUTES_H
16 #define LLVM_PARAMETER_ATTRIBUTES_H
23 /// Attributes - A bitset of attributes for a parameter.
24 typedef unsigned Attributes;
28 /// Function parameters and results can have attributes to indicate how they
29 /// should be treated by optimizations and code generation. This enumeration
30 /// lists the attributes that can be associated with parameters or function
32 /// @brief Function parameter attributes.
34 const Attributes None = 0; ///< No attributes have been set
35 const Attributes ZExt = 1<<0; ///< Zero extended before/after call
36 const Attributes SExt = 1<<1; ///< Sign extended before/after call
37 const Attributes NoReturn = 1<<2; ///< Mark the function as not returning
38 const Attributes InReg = 1<<3; ///< Force argument to be passed in register
39 const Attributes StructRet = 1<<4; ///< Hidden pointer to structure to return
40 const Attributes NoUnwind = 1<<5; ///< Function doesn't unwind stack
41 const Attributes NoAlias = 1<<6; ///< Considered to not alias after call
42 const Attributes ByVal = 1<<7; ///< Pass structure by value
43 const Attributes Nest = 1<<8; ///< Nested function static chain
44 const Attributes ReadNone = 1<<9; ///< Function does not access memory
45 const Attributes ReadOnly = 1<<10; ///< Function only reads from memory
46 const Attributes Alignment = 0xffff<<16; ///< Alignment of parameter (16 bits)
47 // 0 = unknown, else in clear (not log)
49 /// @brief Attributes that only apply to function parameters.
50 const Attributes ParameterOnly = ByVal | Nest | StructRet;
52 /// @brief Attributes that only apply to function return values.
53 const Attributes ReturnOnly = NoReturn | NoUnwind | ReadNone | ReadOnly;
55 /// @brief Parameter attributes that do not apply to vararg call arguments.
56 const Attributes VarArgsIncompatible = StructRet;
58 /// @brief Attributes that are mutually incompatible.
59 const Attributes MutuallyIncompatible[3] = {
60 ByVal | InReg | Nest | StructRet,
65 /// @brief Which attributes cannot be applied to a type.
66 Attributes typeIncompatible(const Type *Ty);
68 /// This turns an int alignment (a power of 2, normally) into the
69 /// form used internally in Attributes.
70 inline Attributes constructAlignmentFromInt(unsigned i) {
74 /// The set of Attributes set in Attributes is converted to a
75 /// string of equivalent mnemonics. This is, presumably, for writing out
76 /// the mnemonics for the assembly writer.
77 /// @brief Convert parameter attribute bits to text
78 std::string getAsString(Attributes Attrs);
79 } // end namespace ParamAttr
82 /// Function notes are implemented as attributes stored at index ~0 in
83 /// parameter attribute list.
84 const Attributes None = 0;
85 const Attributes NoInline = 1<<0; // inline=never
86 const Attributes AlwaysInline = 1<<1; // inline=always
87 const Attributes OptimizeForSize = 1<<2; // opt_size
88 } // end namespace FnAttr
90 /// This is just a pair of values to associate a set of parameter attributes
91 /// with a parameter index.
92 struct FnAttributeWithIndex {
93 Attributes Attrs; ///< The attributes that are set, or'd together.
94 unsigned Index; ///< Index of the parameter for which the attributes apply.
96 static FnAttributeWithIndex get(unsigned Idx, Attributes Attrs) {
97 FnAttributeWithIndex P;
104 //===----------------------------------------------------------------------===//
105 // PAListPtr Smart Pointer
106 //===----------------------------------------------------------------------===//
108 class AttributeListImpl;
110 /// PAListPtr - This class manages the ref count for the opaque
111 /// AttributeListImpl object and provides accessors for it.
113 /// PAList - The parameter attributes that we are managing. This can be null
114 /// to represent the empty parameter attributes list.
115 AttributeListImpl *PAList;
117 PAListPtr() : PAList(0) {}
118 PAListPtr(const PAListPtr &P);
119 const PAListPtr &operator=(const PAListPtr &RHS);
122 //===--------------------------------------------------------------------===//
123 // Parameter Attribute List Construction and Mutation
124 //===--------------------------------------------------------------------===//
126 /// get - Return a ParamAttrs list with the specified parameter in it.
127 static PAListPtr get(const FnAttributeWithIndex *Attr, unsigned NumAttrs);
129 /// get - Return a ParamAttr list with the parameters specified by the
130 /// consecutive random access iterator range.
131 template <typename Iter>
132 static PAListPtr get(const Iter &I, const Iter &E) {
133 if (I == E) return PAListPtr(); // Empty list.
134 return get(&*I, static_cast<unsigned>(E-I));
137 /// addAttr - Add the specified attribute at the specified index to this
138 /// attribute list. Since parameter attribute lists are immutable, this
139 /// returns the new list.
140 PAListPtr addAttr(unsigned Idx, Attributes Attrs) const;
142 /// removeAttr - Remove the specified attribute at the specified index from
143 /// this attribute list. Since parameter attribute lists are immutable, this
144 /// returns the new list.
145 PAListPtr removeAttr(unsigned Idx, Attributes Attrs) const;
147 //===--------------------------------------------------------------------===//
148 // Parameter Attribute List Accessors
149 //===--------------------------------------------------------------------===//
151 /// getParamAttrs - The parameter attributes for the specified parameter are
152 /// returned. Parameters for the result are denoted with Idx = 0.
153 Attributes getParamAttrs(unsigned Idx) const;
155 /// paramHasAttr - Return true if the specified parameter index has the
156 /// specified attribute set.
157 bool paramHasAttr(unsigned Idx, Attributes Attr) const {
158 return getParamAttrs(Idx) & Attr;
161 /// getParamAlignment - Return the alignment for the specified function
163 unsigned getParamAlignment(unsigned Idx) const {
164 return (getParamAttrs(Idx) & ParamAttr::Alignment) >> 16;
167 /// hasAttrSomewhere - Return true if the specified attribute is set for at
168 /// least one parameter or for the return value.
169 bool hasAttrSomewhere(Attributes Attr) const;
171 /// operator==/!= - Provide equality predicates.
172 bool operator==(const PAListPtr &RHS) const { return PAList == RHS.PAList; }
173 bool operator!=(const PAListPtr &RHS) const { return PAList != RHS.PAList; }
177 //===--------------------------------------------------------------------===//
178 // Parameter Attribute List Introspection
179 //===--------------------------------------------------------------------===//
181 /// getRawPointer - Return a raw pointer that uniquely identifies this
182 /// parameter attribute list.
183 void *getRawPointer() const {
187 // Parameter attributes are stored as a dense set of slots, where there is one
188 // slot for each argument that has an attribute. This allows walking over the
189 // dense set instead of walking the sparse list of attributes.
191 /// isEmpty - Return true if no parameters have an attribute.
193 bool isEmpty() const {
197 /// getNumSlots - Return the number of slots used in this attribute list.
198 /// This is the number of arguments that have an attribute set on them
199 /// (including the function itself).
200 unsigned getNumSlots() const;
202 /// getSlot - Return the FnAttributeWithIndex at the specified slot. This
203 /// holds a parameter number plus a set of attributes.
204 const FnAttributeWithIndex &getSlot(unsigned Slot) const;
207 explicit PAListPtr(AttributeListImpl *L);
210 } // End llvm namespace