1 //===-- llvm/ParameterAttributes.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 /// ParameterAttributes - A bitset of attributes for a parameter.
24 typedef unsigned ParameterAttributes;
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.
33 typedef ParameterAttributes Attributes;
35 const Attributes None = 0; ///< No attributes have been set
36 const Attributes ZExt = 1<<0; ///< Zero extended before/after call
37 const Attributes SExt = 1<<1; ///< Sign extended before/after call
38 const Attributes NoReturn = 1<<2; ///< Mark the function as not returning
39 const Attributes InReg = 1<<3; ///< Force argument to be passed in register
40 const Attributes StructRet = 1<<4; ///< Hidden pointer to structure to return
41 const Attributes NoUnwind = 1<<5; ///< Function doesn't unwind stack
42 const Attributes NoAlias = 1<<6; ///< Considered to not alias after call
43 const Attributes ByVal = 1<<7; ///< Pass structure by value
44 const Attributes Nest = 1<<8; ///< Nested function static chain
45 const Attributes ReadNone = 1<<9; ///< Function does not access memory
46 const Attributes ReadOnly = 1<<10; ///< Function only reads from memory
47 const Attributes Alignment = 0xffff<<16; ///< Alignment of parameter (16 bits)
48 // 0 = unknown, else in clear (not log)
50 /// @brief Attributes that only apply to function parameters.
51 const Attributes ParameterOnly = ByVal | InReg | Nest | StructRet;
53 /// @brief Attributes that only apply to function return values.
54 const Attributes ReturnOnly = NoReturn | NoUnwind | ReadNone | ReadOnly;
56 /// @brief Parameter attributes that do not apply to vararg call arguments.
57 const Attributes VarArgsIncompatible = StructRet;
59 /// @brief Attributes that are mutually incompatible.
60 const Attributes MutuallyIncompatible[3] = {
61 ByVal | InReg | Nest | StructRet,
66 /// @brief Which attributes cannot be applied to a type.
67 Attributes typeIncompatible(const Type *Ty);
69 /// This turns an int alignment (a power of 2, normally) into the
70 /// form used internally in ParameterAttributes.
71 ParamAttr::Attributes inline constructAlignmentFromInt(unsigned i) {
75 /// The set of ParameterAttributes set in Attributes is converted to a
76 /// string of equivalent mnemonics. This is, presumably, for writing out
77 /// the mnemonics for the assembly writer.
78 /// @brief Convert parameter attribute bits to text
79 std::string getAsString(ParameterAttributes Attrs);
80 } // end namespace ParamAttr
83 /// This is just a pair of values to associate a set of parameter attributes
84 /// with a parameter index.
85 struct ParamAttrsWithIndex {
86 ParameterAttributes Attrs; ///< The attributes that are set, or'd together.
87 unsigned Index; ///< Index of the parameter for which the attributes apply.
89 static ParamAttrsWithIndex get(unsigned Idx, ParameterAttributes Attrs) {
90 ParamAttrsWithIndex P;
97 //===----------------------------------------------------------------------===//
98 // PAListPtr Smart Pointer
99 //===----------------------------------------------------------------------===//
101 class ParamAttributeListImpl;
103 /// PAListPtr - This class manages the ref count for the opaque
104 /// ParamAttributeListImpl object and provides accessors for it.
106 /// PAList - The parameter attributes that we are managing. This can be null
107 /// to represent the empty parameter attributes list.
108 ParamAttributeListImpl *PAList;
110 PAListPtr() : PAList(0) {}
111 PAListPtr(const PAListPtr &P);
112 const PAListPtr &operator=(const PAListPtr &RHS);
115 //===--------------------------------------------------------------------===//
116 // Parameter Attribute List Construction and Mutation
117 //===--------------------------------------------------------------------===//
119 /// get - Return a ParamAttrs list with the specified parameter in it.
120 static PAListPtr get(const ParamAttrsWithIndex *Attr, unsigned NumAttrs);
122 /// get - Return a ParamAttr list with the parameters specified by the
123 /// consecutive random access iterator range.
124 template <typename Iter>
125 static PAListPtr get(const Iter &I, const Iter &E) {
126 if (I == E) return PAListPtr(); // Empty list.
127 return get(&*I, static_cast<unsigned>(E-I));
130 /// addAttr - Add the specified attribute at the specified index to this
131 /// attribute list. Since parameter attribute lists are immutable, this
132 /// returns the new list.
133 PAListPtr addAttr(unsigned Idx, ParameterAttributes Attrs) const;
135 /// removeAttr - Remove the specified attribute at the specified index from
136 /// this attribute list. Since parameter attribute lists are immutable, this
137 /// returns the new list.
138 PAListPtr removeAttr(unsigned Idx, ParameterAttributes Attrs) const;
140 //===--------------------------------------------------------------------===//
141 // Parameter Attribute List Accessors
142 //===--------------------------------------------------------------------===//
144 /// getParamAttrs - The parameter attributes for the specified parameter are
145 /// returned. Parameters for the result are denoted with Idx = 0.
146 ParameterAttributes getParamAttrs(unsigned Idx) const;
148 /// paramHasAttr - Return true if the specified parameter index has the
149 /// specified attribute set.
150 bool paramHasAttr(unsigned Idx, ParameterAttributes Attr) const {
151 return getParamAttrs(Idx) & Attr;
154 /// getParamAlignment - Return the alignment for the specified function
156 unsigned getParamAlignment(unsigned Idx) const {
157 return (getParamAttrs(Idx) & ParamAttr::Alignment) >> 16;
160 /// hasAttrSomewhere - Return true if the specified attribute is set for at
161 /// least one parameter or for the return value.
162 bool hasAttrSomewhere(ParameterAttributes Attr) const;
164 /// operator==/!= - Provide equality predicates.
165 bool operator==(const PAListPtr &RHS) const { return PAList == RHS.PAList; }
166 bool operator!=(const PAListPtr &RHS) const { return PAList != RHS.PAList; }
170 //===--------------------------------------------------------------------===//
171 // Parameter Attribute List Introspection
172 //===--------------------------------------------------------------------===//
174 /// getRawPointer - Return a raw pointer that uniquely identifies this
175 /// parameter attribute list.
176 void *getRawPointer() const {
180 // Parameter attributes are stored as a dense set of slots, where there is one
181 // slot for each argument that has an attribute. This allows walking over the
182 // dense set instead of walking the sparse list of attributes.
184 /// isEmpty - Return true if no parameters have an attribute.
186 bool isEmpty() const {
190 /// getNumSlots - Return the number of slots used in this attribute list.
191 /// This is the number of arguments that have an attribute set on them
192 /// (including the function itself).
193 unsigned getNumSlots() const;
195 /// getSlot - Return the ParamAttrsWithIndex at the specified slot. This
196 /// holds a parameter number plus a set of attributes.
197 const ParamAttrsWithIndex &getSlot(unsigned Slot) const;
200 explicit PAListPtr(ParamAttributeListImpl *L);
203 } // End llvm namespace