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 /// This class represents an incoming formal argument to a Function. A formal
25 /// argument, since it is ``formal'', does not contain an actual value but
26 /// instead represents the type, argument number, and attributes of an argument
27 /// for a specific function. When used in the body of said function, the
28 /// argument of course represents the value of the actual argument that the
29 /// function was called with.
30 class Argument final : public Value {
31   Function *Parent;
32   unsigned ArgNo;
33 
34   friend class Function;
35   void setParent(Function *parent);
36 
37 public:
38   /// Argument constructor.
39   explicit Argument(Type *Ty, const Twine &Name = "", Function *F = nullptr,
40                     unsigned ArgNo = 0);
41 
getParent()42   inline const Function *getParent() const { return Parent; }
getParent()43   inline       Function *getParent()       { return Parent; }
44 
45   /// Return the index of this formal argument in its containing function.
46   ///
47   /// For example in "void foo(int a, float b)" a is 0 and b is 1.
getArgNo()48   unsigned getArgNo() const {
49     assert(Parent && "can't get number of unparented arg");
50     return ArgNo;
51   }
52 
53   /// Return true if this argument has the nonnull attribute. Also returns true
54   /// if at least one byte is known to be dereferenceable and the pointer is in
55   /// addrspace(0).
56   bool hasNonNullAttr() const;
57 
58   /// If this argument has the dereferenceable attribute, return the number of
59   /// bytes known to be dereferenceable. Otherwise, zero is returned.
60   uint64_t getDereferenceableBytes() const;
61 
62   /// If this argument has the dereferenceable_or_null attribute, return the
63   /// number of bytes known to be dereferenceable. Otherwise, zero is returned.
64   uint64_t getDereferenceableOrNullBytes() const;
65 
66   /// Return true if this argument has the byval attribute.
67   bool hasByValAttr() const;
68 
69   /// Return true if this argument has the swiftself attribute.
70   bool hasSwiftSelfAttr() const;
71 
72   /// Return true if this argument has the swifterror attribute.
73   bool hasSwiftErrorAttr() const;
74 
75   /// Return true if this argument has the byval attribute or inalloca
76   /// attribute. These attributes represent arguments being passed by value.
77   bool hasByValOrInAllocaAttr() const;
78 
79   /// If this is a byval or inalloca argument, return its alignment.
80   unsigned getParamAlignment() const;
81 
82   /// Return true if this argument has the nest attribute.
83   bool hasNestAttr() const;
84 
85   /// Return true if this argument has the noalias attribute.
86   bool hasNoAliasAttr() const;
87 
88   /// Return true if this argument has the nocapture attribute.
89   bool hasNoCaptureAttr() const;
90 
91   /// Return true if this argument has the sret attribute.
92   bool hasStructRetAttr() const;
93 
94   /// Return true if this argument has the returned attribute.
95   bool hasReturnedAttr() const;
96 
97   /// Return true if this argument has the readonly or readnone attribute.
98   bool onlyReadsMemory() const;
99 
100   /// Return true if this argument has the inalloca attribute.
101   bool hasInAllocaAttr() const;
102 
103   /// Return true if this argument has the zext attribute.
104   bool hasZExtAttr() const;
105 
106   /// Return true if this argument has the sext attribute.
107   bool hasSExtAttr() const;
108 
109   /// Add attributes to an argument.
110   void addAttrs(AttrBuilder &B);
111 
112   void addAttr(Attribute::AttrKind Kind);
113 
114   void addAttr(Attribute Attr);
115 
116   /// Remove attributes from an argument.
117   void removeAttr(Attribute::AttrKind Kind);
118 
119   /// Check if an argument has a given attribute.
120   bool hasAttribute(Attribute::AttrKind Kind) const;
121 
122   /// Method for support type inquiry through isa, cast, and dyn_cast.
classof(const Value * V)123   static bool classof(const Value *V) {
124     return V->getValueID() == ArgumentVal;
125   }
126 };
127 
128 } // End llvm namespace
129 
130 #endif
131