1 //===-- llvm/ParameterAttributes.h - Container for Param Attrs --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the types necessary to represent the parameter attributes
11 // associated with functions and their calls.
13 // The implementations of these classes live in lib/VMCore/Function.cpp.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_PARAMETER_ATTRIBUTES_H
18 #define LLVM_PARAMETER_ATTRIBUTES_H
20 #include <llvm/ADT/SmallVector.h>
24 /// Function parameters can have attributes to indicate how they should be
25 /// treated by optimizations and code generation. This enumeration lists the
26 /// attributes that can be associated with parameters or function results.
27 /// @brief Function parameter attributes.
28 enum ParameterAttributes {
29 NoAttributeSet = 0, ///< No attributes have been set
30 ZExtAttribute = 1 << 0, ///< zero extended before/after call
31 SExtAttribute = 1 << 1, ///< sign extended before/after call
32 NoReturnAttribute = 1 << 2, ///< mark the function as not returning
33 InRegAttribute = 1 << 3, ///< force argument to be passed in register
34 StructRetAttribute = 1 << 4, ///< hidden pointer to structure to return
35 NoUnwindAttribute = 1 << 5 ///< Function doesn't unwind stack
38 /// This class is used by Function and CallInst to represent the set of
39 /// parameter attributes used. It represents a list of pairs of uint16_t, one
40 /// for the parameter index, and one a set of ParameterAttributes bits.
41 /// Parameters that have no attributes are not present in the list. The list
42 /// may also be empty, but this doesn't occur in practice. The list constructs
43 /// as empty and is filled by the insert method. The list can be turned into
44 /// a string of mnemonics suitable for LLVM Assembly output. Various accessors
45 /// are provided to obtain information about the attributes.
46 /// @brief A List of ParameterAttributes.
47 class ParamAttrsList {
51 /// Returns the parameter index of a particular parameter attribute in this
52 /// list of attributes. Note that the attr_index is an index into this
53 /// class's list of attributes, not the index of the parameter. The result
54 /// is the index of the parameter.
55 /// @brief Get a parameter index
56 uint16_t getParamIndex(unsigned attr_index) const {
57 return attrs[attr_index].index;
60 /// The parameter attributes for the \p indexth parameter are returned.
61 /// The 0th parameter refers to the return type of the function. Note that
62 /// the \p param_index is an index into the function's parameters, not an
63 /// index into this class's list of attributes. The result of getParamIndex
64 /// is always suitable input to this function.
65 /// @returns The all the ParameterAttributes for the \p indexth parameter
66 /// as a uint16_t of enumeration values OR'd together.
67 /// @brief Get the attributes for a parameter
68 uint16_t getParamAttrs(uint16_t param_index) const;
70 /// This checks to see if the \p ith function parameter has the parameter
71 /// attribute given by \p attr set.
72 /// @returns true if the parameter attribute is set
73 /// @brief Determine if a ParameterAttributes is set
74 bool paramHasAttr(uint16_t i, ParameterAttributes attr) const {
75 return getParamAttrs(i) & attr;
78 /// Determines how many parameter attributes are set in this ParamAttrsList.
79 /// This says nothing about how many parameters the function has. It also
80 /// says nothing about the highest parameter index that has attributes.
81 /// @returns the number of parameter attributes in this ParamAttrsList.
82 /// @brief Return the number of parameter attributes this type has.
83 unsigned size() const { return attrs.size(); }
85 /// @returns true if this ParamAttrsList is empty.
86 /// @brief Determine emptiness of ParamAttrsList.
87 unsigned empty() const { return attrs.empty(); }
89 /// The set of ParameterAttributes set in Attributes is converted to a
90 /// string of equivalent mnemonics. This is, presumably, for writing out
91 /// the mnemonics for the assembly writer.
92 /// @brief Convert parameter attribute bits to text
93 static std::string getParamAttrsText(uint16_t Attributes);
95 /// The \p Indexth parameter attribute is converted to string.
96 /// @brief Get the text for the parmeter attributes for one parameter.
97 std::string getParamAttrsTextByIndex(uint16_t Index) const {
98 return getParamAttrsText(getParamAttrs(Index));
101 /// @brief Comparison operator for ParamAttrsList
102 bool operator < (const ParamAttrsList& that) const {
103 if (this->attrs.size() < that.attrs.size())
105 if (this->attrs.size() > that.attrs.size())
107 for (unsigned i = 0; i < attrs.size(); ++i) {
108 if (attrs[i].index < that.attrs[i].index)
110 if (attrs[i].index > that.attrs[i].index)
112 if (attrs[i].attrs < that.attrs[i].attrs)
114 if (attrs[i].attrs > that.attrs[i].attrs)
123 /// This adds a pair to the list of parameter index and attribute pairs
124 /// represented by this class. No check is made to determine whether
125 /// param_index exists already. This pair is just added to the end. It is
126 /// the user's responsibility to insert the pairs wisely.
127 /// @brief Insert ParameterAttributes for an index
128 void insert(uint16_t param_index, uint16_t attrs);
134 /// This is an internal structure used to associate the ParameterAttributes
135 /// with a parameter index.
136 /// @brief ParameterAttributes with a parameter index.
137 struct ParamAttrsWithIndex {
138 uint16_t attrs; ///< The attributes that are set, |'d together
139 uint16_t index; ///< Index of the parameter for which the attributes apply
142 SmallVector<ParamAttrsWithIndex,2> attrs; ///< The list of attributes
146 } // End llvm namespace