1 //===-- llvm/IR/Comdat.h - Comdat definitions -------------------*- 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 /// @file
11 /// This file contains the declaration of the Comdat class, which represents a
12 /// single COMDAT in LLVM.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_IR_COMDAT_H
17 #define LLVM_IR_COMDAT_H
18 
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/Support/Compiler.h"
21 
22 namespace llvm {
23 
24 class raw_ostream;
25 template <typename ValueTy> class StringMapEntry;
26 
27 // This is a Name X SelectionKind pair. The reason for having this be an
28 // independent object instead of just adding the name and the SelectionKind
29 // to a GlobalObject is that it is invalid to have two Comdats with the same
30 // name but different SelectionKind. This structure makes that unrepresentable.
31 class Comdat {
32 public:
33   enum SelectionKind {
34     Any,          ///< The linker may choose any COMDAT.
35     ExactMatch,   ///< The data referenced by the COMDAT must be the same.
36     Largest,      ///< The linker will choose the largest COMDAT.
37     NoDuplicates, ///< No other Module may specify this COMDAT.
38     SameSize,     ///< The data referenced by the COMDAT must be the same size.
39   };
40 
41   Comdat(Comdat &&C);
getSelectionKind()42   SelectionKind getSelectionKind() const { return SK; }
setSelectionKind(SelectionKind Val)43   void setSelectionKind(SelectionKind Val) { SK = Val; }
44   StringRef getName() const;
45   void print(raw_ostream &OS) const;
46   void dump() const;
47 
48 private:
49   friend class Module;
50   Comdat();
51   Comdat(SelectionKind SK, StringMapEntry<Comdat> *Name);
52   Comdat(const Comdat &) = delete;
53 
54   // Points to the map in Module.
55   StringMapEntry<Comdat> *Name;
56   SelectionKind SK;
57 };
58 
59 inline raw_ostream &operator<<(raw_ostream &OS, const Comdat &C) {
60   C.print(OS);
61   return OS;
62 }
63 
64 } // end llvm namespace
65 
66 #endif
67