1 //===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===//
2 //
3 //
4 // The LLVM Compiler Infrastructure
5 //
6 // This file is distributed under the University of Illinois Open Source
7 // License. See LICENSE.TXT for details.
8 //
9 //===----------------------------------------------------------------------===//
10 //
11 // This file declares some helpers classes to handle Linker Optimization Hint
12 // (LOH).
13 //
14 // FIXME: LOH interface supports only MachO format at the moment.
15 //===----------------------------------------------------------------------===//
16
17 #ifndef LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
18 #define LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
19
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/StringSwitch.h"
23 #include "llvm/Support/raw_ostream.h"
24
25 namespace llvm {
26
27 // Forward declarations.
28 class MCAsmLayout;
29 class MCSymbol;
30
31 /// Linker Optimization Hint Type.
32 enum MCLOHType {
33 MCLOH_AdrpAdrp = 0x1u, ///< Adrp xY, _v1@PAGE -> Adrp xY, _v2@PAGE.
34 MCLOH_AdrpLdr = 0x2u, ///< Adrp _v@PAGE -> Ldr _v@PAGEOFF.
35 MCLOH_AdrpAddLdr = 0x3u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Ldr.
36 MCLOH_AdrpLdrGotLdr = 0x4u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Ldr.
37 MCLOH_AdrpAddStr = 0x5u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Str.
38 MCLOH_AdrpLdrGotStr = 0x6u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Str.
39 MCLOH_AdrpAdd = 0x7u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF.
40 MCLOH_AdrpLdrGot = 0x8u ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF.
41 };
42
MCLOHDirectiveName()43 static inline StringRef MCLOHDirectiveName() {
44 return StringRef(".loh");
45 }
46
isValidMCLOHType(unsigned Kind)47 static inline bool isValidMCLOHType(unsigned Kind) {
48 return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
49 }
50
MCLOHNameToId(StringRef Name)51 static inline int MCLOHNameToId(StringRef Name) {
52 #define MCLOHCaseNameToId(Name) .Case(#Name, MCLOH_ ## Name)
53 return StringSwitch<int>(Name)
54 MCLOHCaseNameToId(AdrpAdrp)
55 MCLOHCaseNameToId(AdrpLdr)
56 MCLOHCaseNameToId(AdrpAddLdr)
57 MCLOHCaseNameToId(AdrpLdrGotLdr)
58 MCLOHCaseNameToId(AdrpAddStr)
59 MCLOHCaseNameToId(AdrpLdrGotStr)
60 MCLOHCaseNameToId(AdrpAdd)
61 MCLOHCaseNameToId(AdrpLdrGot)
62 .Default(-1);
63 }
64
MCLOHIdToName(MCLOHType Kind)65 static inline StringRef MCLOHIdToName(MCLOHType Kind) {
66 #define MCLOHCaseIdToName(Name) case MCLOH_ ## Name: return StringRef(#Name);
67 switch (Kind) {
68 MCLOHCaseIdToName(AdrpAdrp);
69 MCLOHCaseIdToName(AdrpLdr);
70 MCLOHCaseIdToName(AdrpAddLdr);
71 MCLOHCaseIdToName(AdrpLdrGotLdr);
72 MCLOHCaseIdToName(AdrpAddStr);
73 MCLOHCaseIdToName(AdrpLdrGotStr);
74 MCLOHCaseIdToName(AdrpAdd);
75 MCLOHCaseIdToName(AdrpLdrGot);
76 }
77 return StringRef();
78 }
79
MCLOHIdToNbArgs(MCLOHType Kind)80 static inline int MCLOHIdToNbArgs(MCLOHType Kind) {
81 switch (Kind) {
82 // LOH with two arguments
83 case MCLOH_AdrpAdrp:
84 case MCLOH_AdrpLdr:
85 case MCLOH_AdrpAdd:
86 case MCLOH_AdrpLdrGot:
87 return 2;
88 // LOH with three arguments
89 case MCLOH_AdrpAddLdr:
90 case MCLOH_AdrpLdrGotLdr:
91 case MCLOH_AdrpAddStr:
92 case MCLOH_AdrpLdrGotStr:
93 return 3;
94 }
95 return -1;
96 }
97
98 /// Store Linker Optimization Hint information (LOH).
99 class MCLOHDirective {
100 MCLOHType Kind;
101
102 /// Arguments of this directive. Order matters.
103 SmallVector<MCSymbol *, 3> Args;
104
105 public:
106 typedef SmallVectorImpl<MCSymbol *> LOHArgs;
107
MCLOHDirective(MCLOHType Kind,const LOHArgs & Args)108 MCLOHDirective(MCLOHType Kind, const LOHArgs &Args)
109 : Kind(Kind), Args(Args.begin(), Args.end()) {
110 assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
111 }
112
getKind()113 MCLOHType getKind() const { return Kind; }
114
getArgs()115 const LOHArgs &getArgs() const { return Args; }
116 };
117
118 class MCLOHContainer {
119 /// Keep track of the emit size of all the LOHs.
120 mutable uint64_t EmitSize;
121
122 /// Keep track of all LOH directives.
123 SmallVector<MCLOHDirective, 32> Directives;
124
125 public:
126 typedef SmallVectorImpl<MCLOHDirective> LOHDirectives;
127
MCLOHContainer()128 MCLOHContainer() : EmitSize(0) {}
129
130 /// Const accessor to the directives.
getDirectives()131 const LOHDirectives &getDirectives() const {
132 return Directives;
133 }
134
135 /// Add the directive of the given kind \p Kind with the given arguments
136 /// \p Args to the container.
addDirective(MCLOHType Kind,const MCLOHDirective::LOHArgs & Args)137 void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args) {
138 Directives.push_back(MCLOHDirective(Kind, Args));
139 }
140
reset()141 void reset() {
142 Directives.clear();
143 EmitSize = 0;
144 }
145 };
146
147 // Add types for specialized template using MCSymbol.
148 typedef MCLOHDirective::LOHArgs MCLOHArgs;
149 typedef MCLOHContainer::LOHDirectives MCLOHDirectives;
150
151 } // end namespace llvm
152
153 #endif
154