1 //===-- llvm/Argument.h - Definition of the Argument class ------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file declares the Argument class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_IR_ARGUMENT_H
15 #define LLVM_IR_ARGUMENT_H
16 
17 #include "llvm/ADT/Twine.h"
18 #include "llvm/ADT/ilist_node.h"
19 #include "llvm/IR/Attributes.h"
20 #include "llvm/IR/Value.h"
21 
22 namespace llvm {
23 
24 template <typename NodeTy> class SymbolTableListTraits;
25 
26 /// \brief LLVM Argument representation
27 ///
28 /// This class represents an incoming formal argument to a Function. A formal
29 /// argument, since it is ``formal'', does not contain an actual value but
30 /// instead represents the type, argument number, and attributes of an argument
31 /// for a specific function. When used in the body of said function, the
32 /// argument of course represents the value of the actual argument that the
33 /// function was called with.
34 class Argument : public Value, public ilist_node<Argument> {
35   virtual void anchor();
36   Function *Parent;
37 
38   friend class SymbolTableListTraits<Argument>;
39   void setParent(Function *parent);
40 
41 public:
42   /// \brief Constructor.
43   ///
44   /// If \p F is specified, the argument is inserted at the end of the argument
45   /// list for \p F.
46   explicit Argument(Type *Ty, const Twine &Name = "", Function *F = nullptr);
47 
48   inline const Function *getParent() const { return Parent; }
49   inline       Function *getParent()       { return Parent; }
50 
51   /// \brief Return the index of this formal argument in its containing
52   /// function.
53   ///
54   /// For example in "void foo(int a, float b)" a is 0 and b is 1.
55   unsigned getArgNo() const;
56 
57   /// \brief Return true if this argument has the nonnull attribute on it in
58   /// its containing function. Also returns true if at least one byte is known
59   /// to be dereferenceable and the pointer is in addrspace(0).
60   bool hasNonNullAttr() const;
61 
62   /// \brief If this argument has the dereferenceable attribute on it in its
63   /// containing function, return the number of bytes known to be
64   /// dereferenceable. Otherwise, zero is returned.
65   uint64_t getDereferenceableBytes() const;
66 
67   /// \brief If this argument has the dereferenceable_or_null attribute on
68   /// it in its containing function, return the number of bytes known to be
69   /// dereferenceable. Otherwise, zero is returned.
70   uint64_t getDereferenceableOrNullBytes() const;
71 
72   /// \brief Return true if this argument has the byval attribute on it in its
73   /// containing function.
74   bool hasByValAttr() const;
75 
76   /// \brief Return true if this argument has the swiftself attribute.
77   bool hasSwiftSelfAttr() const;
78 
79   /// \brief Return true if this argument has the swifterror attribute.
80   bool hasSwiftErrorAttr() const;
81 
82   /// \brief Return true if this argument has the byval attribute or inalloca
83   /// attribute on it in its containing function.  These attributes both
84   /// represent arguments being passed by value.
85   bool hasByValOrInAllocaAttr() const;
86 
87   /// \brief If this is a byval or inalloca argument, return its alignment.
88   unsigned getParamAlignment() const;
89 
90   /// \brief Return true if this argument has the nest attribute on it in its
91   /// containing function.
92   bool hasNestAttr() const;
93 
94   /// \brief Return true if this argument has the noalias attribute on it in its
95   /// containing function.
96   bool hasNoAliasAttr() const;
97 
98   /// \brief Return true if this argument has the nocapture attribute on it in
99   /// its containing function.
100   bool hasNoCaptureAttr() const;
101 
102   /// \brief Return true if this argument has the sret attribute on it in its
103   /// containing function.
104   bool hasStructRetAttr() const;
105 
106   /// \brief Return true if this argument has the returned attribute on it in
107   /// its containing function.
108   bool hasReturnedAttr() const;
109 
110   /// \brief Return true if this argument has the readonly or readnone attribute
111   /// on it in its containing function.
112   bool onlyReadsMemory() const;
113 
114   /// \brief Return true if this argument has the inalloca attribute on it in
115   /// its containing function.
116   bool hasInAllocaAttr() const;
117 
118   /// \brief Return true if this argument has the zext attribute on it in its
119   /// containing function.
120   bool hasZExtAttr() const;
121 
122   /// \brief Return true if this argument has the sext attribute on it in its
123   /// containing function.
124   bool hasSExtAttr() const;
125 
126   /// \brief Add a Attribute to an argument.
127   void addAttr(AttributeSet AS);
128 
129   void addAttr(Attribute::AttrKind Kind) {
130     addAttr(AttributeSet::get(getContext(), getArgNo() + 1, Kind));
131   }
132 
133   /// \brief Remove a Attribute from an argument.
134   void removeAttr(AttributeSet AS);
135 
136   void removeAttr(Attribute::AttrKind Kind) {
137     removeAttr(AttributeSet::get(getContext(), getArgNo() + 1, Kind));
138   }
139 
140   /// \brief Checks if an argument has a given attribute.
141   bool hasAttribute(Attribute::AttrKind Kind) const;
142 
143   /// \brief Method for support type inquiry through isa, cast, and
144   /// dyn_cast.
145   static inline bool classof(const Value *V) {
146     return V->getValueID() == ArgumentVal;
147   }
148 };
149 
150 } // End llvm namespace
151 
152 #endif
153