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 
getParent()48   inline const Function *getParent() const { return Parent; }
getParent()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 byval attribute or inalloca
77   /// attribute on it in its containing function.  These attributes both
78   /// represent arguments being passed by value.
79   bool hasByValOrInAllocaAttr() const;
80 
81   /// \brief If this is a byval or inalloca argument, return its alignment.
82   unsigned getParamAlignment() const;
83 
84   /// \brief Return true if this argument has the nest attribute on it in its
85   /// containing function.
86   bool hasNestAttr() const;
87 
88   /// \brief Return true if this argument has the noalias attribute on it in its
89   /// containing function.
90   bool hasNoAliasAttr() const;
91 
92   /// \brief Return true if this argument has the nocapture attribute on it in
93   /// its containing function.
94   bool hasNoCaptureAttr() const;
95 
96   /// \brief Return true if this argument has the sret attribute on it in its
97   /// containing function.
98   bool hasStructRetAttr() const;
99 
100   /// \brief Return true if this argument has the returned attribute on it in
101   /// its containing function.
102   bool hasReturnedAttr() const;
103 
104   /// \brief Return true if this argument has the readonly or readnone attribute
105   /// on it in its containing function.
106   bool onlyReadsMemory() const;
107 
108   /// \brief Return true if this argument has the inalloca attribute on it in
109   /// its containing function.
110   bool hasInAllocaAttr() const;
111 
112   /// \brief Return true if this argument has the zext attribute on it in its
113   /// containing function.
114   bool hasZExtAttr() const;
115 
116   /// \brief Return true if this argument has the sext attribute on it in its
117   /// containing function.
118   bool hasSExtAttr() const;
119 
120   /// \brief Add a Attribute to an argument.
121   void addAttr(AttributeSet AS);
122 
123   /// \brief Remove a Attribute from an argument.
124   void removeAttr(AttributeSet AS);
125 
126   /// \brief Method for support type inquiry through isa, cast, and
127   /// dyn_cast.
classof(const Value * V)128   static inline bool classof(const Value *V) {
129     return V->getValueID() == ArgumentVal;
130   }
131 };
132 
133 } // End llvm namespace
134 
135 #endif
136